synthesis and characterization of schiff base metal complex

Prepared by Tesfaye Tebeka 1

APPLIED SCIENCE FACULTY APPLIED CHEMISTRY DEPARTMENT

STUDENT PROJECT ON:-

SYNTHESIS AND CHARACTERIZATION OF SCHIFF BASE META L

COMPLEX DERIVED FROM AMINO ACID AND NINHYDRIN

ADVISOR: ATO BELETE YILMA(M.Sc)

BY TESFAYE TEBEKA in Partial Fulfillment of the Requirements for the of Bachelor of Degree in applied chemistry. JUNE, 2009


TABLE OF CONTENT CONTENT PAGE Abbreviation i Acknowledgement ii Abstract iii CHAPTER ONE ............................................................................................................... 8 1 INTRODUCTION .......................................................................................................... 8

1.1 Synthesis of Schiff base metal complexes.............................................................. 8 CHAPTER TWO ............................................................................................................ 11 Literature review ............................................................................................................ 11 2. Schiff bases components under investigation........................................................... 11

2.1. Amino acids.......................................................................................................... 11 2.2 NINHYDRIN ......................................................................................................... 14

2.2 1 REACTIVITY ................................................................................................ 15 2.2.2 The ninhydrin reaction with amino acids and their mechanism............... 15 2.2.3 Mechanism reaction of ninhydrin and amino acids ................................... 17

2.3 Schiff Bases............................................................................................................ 18 2.3.1 Biological Important Of Schiff Base............................................................ 19 2.3.2 Catalytic applications of Schiff bases........................................................... 20

2.4 The chemistry of metal ions................................................................................. 21 2. 4.1 Cobalt II) complexes..................................................................................... 22 2.4.2 Nickel (11) complexes.................................................................................... 23

2.5 Objectives and the scope of the present studies................................................. 24 2.5.1General objective............................................................................................ 24 2.5.2 Specific objectives.......................................................................................... 24

CHAPTER THREE .......................................................................................................... 25 3 Materials and methodology....................................................................................... 25

3.1 Apparatus and instruments............................................................................... 25 3.2 General procedures............................................................................................... 25

3.2.1 Synthesis of Schiff base derived from cystein with Ninhydrin ............... 25 3.2.2 Synthesis of Ruhmann’s purple.................................................................... 25 3.2.3 Synthesis of Schiff base metal complex........................................................ 26 3.2.4 Synthesis of Ruhmann’spurple metal complexes...................................... 26 3.2.5 Ruhmann’s purple metal complex of lysine and ninhydrin ....................... 26

3.3 Characterization of complexes........................................................................... 27 3.3.1 Thin layer chromatography.......................................................................... 27 3.3.2 Solubility......................................................................................................... 27 3.3.3 Melting (decomposition points).................................................................... 27 3.3.4 Conductivity measurements.......................................................................... 27


3.3.5 Electronic absorption spectra....................................................................... 27 3.3.6 Flame atomic absorption spectroscopy........................................................ 27

CHAPTER FOUR......................................................................................................... 28 4 RESULTS..................................................................................................................... 28

4.2 DISCUSSION........................................................................................................ 32 4.2.1 Molar conductance studies............................................................................ 32 4.2.2 UV-Visible spectroscopic analysis................................................................ 32 4.2.3 Atomic absorption spectroscopy................................................................... 33

5 Conclusions................................................................................................................... 35 6 Recommendations........................................................................................................ 37 7 REFERENCES........................................................................................................... 38 8 Appendixes.................................................................................................................... 39


List of tables Pages Table-1 Physical characteristics………………………………… 21

Table- 2 soluble test of complex indifferent solvent…………… 21

Table -3 – molar conductance values Ruhmann’s purple metal complex. 22

Table-4 Spectral data of metal complexes of Ruhmann’s purple….. 23

Table - 5 A for Ni complex……………………………………… 23

Table - 5 B for Ni complex………………………………………… 23

Table- 5 C for Co-complex……………………………………… 24

.


ABBREVIATION Abs. = absorbance

UV. Vis = ultra violet visible spectroscopy

Sch. = Schiff base

Ruhm’s = Ruhmann’s purple

Λm = molar conductivity

Ω-1 = Ohm inverse

Ns = Nano semin

Ml = Milliliter

Mmol = mili mol

Cm~1 = centimeter inverse

Co = degree cent grade

gm = gram

Co = Cobalt

Ni = Nickel

ε = Molar absorbtivity

AAS = Atomic absorption spectroscope

TLC = Thin layer chromatography Fig = figure

i


Acknowledgement

I would like to express our sincere gratitude and indebted ness to our advisor Mr. Belete

Yilma (M.Sc) for giving reference Material and making himself available for advice at

time I need. The untiring guidance during the project work and available for advice at

time I need. The untiring guidance during the project work and valuable comments on

how to write the final project report were unforgettable I have really enjoyed working

under his supervision.

I extend special thank to Wondimegn, Solomon, Behailu to share their knowledge and

experiences during the experiments was done in their individual laboratory.

A specific acknowledgement and grateful application goes to librarians and Wondimegn

for their generous cooperation in providing me the necessary books and equipment when

required. I also really appreciate Mrs.AlexT.Kuvarega who supported us in instrumental

operation.

Above all, thanks to the Almighty God, nothing can make us forget his loving care during

our stay in Arbaminch University. Finally, I never forget the generous help of our

department and all other who have helped me giving us morals and material during three

years stay in AMU.

ii


Abstracts Complexes of Co(II) and Ni(II) with Ruhmann’s Purple derived from three amino acids

namely, Iso-Leucine, Glutamine and lysine with ninhydrin and metal complexes of

Schiff base derived from cystein with ninhydrin was synthesized. The complexes were

distinctly colored and stable to atmospheric conditions. The complexes were

characterized by molar conductance and electronic studies (U V-vis and Atomic

absorption spectroroscopy)

The ligands were shown to behave as a monodentate, bidentate (ON or OO) and

tridentate (ONO) donor and the ketimine (the Schiff base) being to relatively greater

potential, because it can act as tridentate and forming two stable five membered ring on

complexation with metal ions.

After using all the characterization parameter, the Schiff base and Ruhmann’s purple

complexes of CO (II) and Ni (II) were proposed to an octahedral, geometry and 1: 2

metals to ligands ratio was suggested, in addition to this the molar conductance value is

in the range between 17.6-120 Ω-1 cm2mol-1 ,indicates that the synthesized Schiff base

and ruhmanns purple metal complexes were non electrolytic nature .

iii


CHAPTER ONE

1 INTRODUCTION 1.1 Synthesis of Schiff base metal complexes

The term complex in chemistry is usually used to describe molecules formed by the

combination of liquid and metal ions. Originally a complex implied a reversible

association of molecule, atoms, or ions thorough weak chemical bond [1].

As applied to coordination chemistry this meaning has evolved some metal complexes

are formed virtually irreversibly and many are bind together by bonds that are quite

strong [1].

Metal complex also known as coordination compounds, coordination complex were

known although not understood in any sense. Since the beginning of chemistry, example

Prussian blue and copper vitrid. The key break through occurs when Alfred Werner

proposed; among other things that Co (III) bears six ligands in an octahedral geometry.

The theory allows one to understand the different between coordinated many ionic

chloride in the cobalt ammine chloride and to explain many of the previously in

applicable isomerism.

Schiff base is any derivative of the condensation of aldehydes or ketones with primary

amines. It is colorless, crystal and weakly basic, hydrolyzed by water and strong acids to

form carbonyl compounds and amine. It will be used as chemical intermediates and

perfume bases in dyes and rubber accelerator and liquid crystal for electronics.

Schiff base is a functional group that contains a C-N double bond (C=N) with the

nitrogen atoms connected to an aryl or alkyl group but not hydrogen.

They usually formed by condensation of primary amine with a carbonyl compound

according to the following scheme:

R- NH2 + CR'

O

R R- N = CH-R+H2 where R’ =H or CH3


Where R may be aliphatic or aromatic group .Schiff bases of aliphatic aldehydes are

reality unstable and are readily polymerizable while those of aromatic aldehydes, having

an effective conjugation system, are more stable [2].

Schiff base and its complexes have a variety of application including biological, chemical

and analytical. Earlier work has shown that some drugs showed increase activity when

administrated as metal chalets rather than as organic compounds. But, recently a

particular attention has given to the synthesis and study of diamino tetra dentate Schiff

base and their complexes. This is due to a variety of reasons, not the least of which in

their crucial role in some biological process such as the biological function of

bacterohodospin. These complexes are used in some chemical processes as catalyst and

as biological models in understanding the structure of bimolecular and biological process

in addition to this, transition metal complexes with Schiff base having a varied theoretical

and practical applications: some of them are capable of reversibly binding molecular

oxygen , oxidative catalyst and sensor designs .

A wide variety of ligands may be obtained via the Schiff base condensation reaction

which varies in identity ,flexibility ,nature of donor atoms and electronic properties .the

azomethine ( > C=N ) stretching frequencies of the ligands occur in the region between

1680 and 1603 cm -1 depending up on the nature of subsistent present either on nitrogen

or on carbon .alkyladimines absorb in the 1675 – 1665 cm -1 region and this falls by 10 –

20 cm -1 for any substitution at either end of the double bond. less data are available on

ketimine, but derivatives of biphenyl ketimine absorb near 1620 cm -1 in polar solvent the

monomer forms give rise to absorption in the 1630 – 1620 cm-1 region, but in non polar

solvent s such as hexane the band is at 1590 cm -1 or less due the dimmer .up on

coordination to the meat ions through both oxygen and nitrogen a decrease of > C=N

frequency is generally observed [3]. One of the most components that used to synthesize

Schiff base metal complexes is amino acid.

Proteins are one of the major macromelules in living system. The function of a protein is

primarily determine by its structure, which in turn is determined by the sequence of

aminoacides making up the protein .the amino acid sequence is genetically determined

and is responsible for the slope, physical characterized ,and biological activity of the

protein .


The qualitative and quantitative determined of amino acids, peptides and protein is major

and growing importance in many a reas of biochemical investigations. The most sensitive

reaction is that between amino acids and Ninhydrin, which produces a characteristic

purple closed compound, called Ruhmann’s purple or diketohydrinedylene amine.

The reaction however, is not selective enough because all amine acids except protein (an

amino acid) give the same color .the investigation on the metal complex ( divalent Co,Ni

and Zn ) of glycine Schiff base indicates that in the presence of the meta ion, Ruhmann’s

purple is not formed ,rather a product with specific color could be isolated .


CHAPTER TWO

Literature review

2. Schiff bases components under investigation

2.1. Amino acids

Proteins are polymers of amino acids, with each acid residence joined to its neighbor by a

specific type of covalent bond. Protein can be broken down, hydrolyzed to their

constituent aminoacides by a variety of methods, and the earliest studies of proteins

naturally focused on the free amines acids derived from them. Twenty different amino

acids are commonly found in proteins, all the amino acids have trivial or common names,

in some cases derived from the source which they were first isolated. Asparagines were

first found in asparagus, and glutamate in wheat gluten; tyrosine was first isolated from

cheese and glysine was so named because of its sweet taste.

Amino acid share common structural features.

All the 20 amino acids are α– amino acids .They have a carboxyl group bonded to the

same carbon atom [the x carbon]. They differ from each other in their side chains, or R

groups, which vary in structure, size, and electric change, and which influence the

solubility of the amino acids in water.

The common amino acids of proteins have been assigned three letter abbreviations and

one letter .the general structure of amino acid:

+N3H C

R

COO-

H

Where R =hydrocarbon chain and sulphur containing carbon

Amino acids can be classified R group.

The amino acids can be group into five main classes based on the properties of their R

group, in particularly, their polarity or tendency to interact with water at biological PH

value, near PH 7.0. The polarity of the R groups varies widely, from non polar and

hydrophobic, water hating to highly polar and hydrophilic; water loving.


.

Free amino acids at near PH 7.0.where the species NH2-CHR-COO-

is predominant , are good ligand and from stable five member chelate rings .under other

PH condition s this may not be the case .an amino acid molecules has three donor groups

The amine group of the N- terminus

The carboxyl group of the C- terminus and

The functional group of the side chain are some times potential candidates.

The non-protein associated amino acids perform specialized function. Several of the

amino acid found in proteins also lese functions distinct from the formation of peptides

and proteins, example, tyrosine in the formation of thyroid hormones or glutamate acting

as a never transmitted.

The amino acid under the present investigation being Iso Lucien glutamine, cystein in

and lysine. Same of their general characteristics are presented here.

Glutamine-or-/S/-2-amino-4-carbamoye botanic acid is a polar amino acid and soluble in

water (hydrophilic). Glutamine (C5H10ON2O3) has boiling point of 653 k and melting

point 507.66k.The empirical formula of C5H10ON2O3 with the composition of the

constituent elements carbon 41.09% hydrogen 6.8%, nitrogen 19.178%, and oxygen

32.87%. This amino acid has a molecular mass of 146g/mol. The structure and

designation of the stereoisomer is the following:

COOH

CH2N H

CH2

CH2

C O

NH2

2-amino-4-carbamoylbutanoic acidL-

COOH

C NH2

CH2

CH2

C O

NH2

H

2-amino-4-carbamoylbutanoic acidD-


Iso-leucine –(2S, 3S)-2- amino -3- matched pentatonic acid (C6H,3NO2) it has melting

point of 370.74k and boiling point is 554.04k.

This amino acid has an empirical formula of C6H, 3NO2 with the constituent elements:

carbon 54.941., hydrogen 9.99%, nitrogen 10.68% and oxygen 24.39%. This amino acid

has molecules mass of 131.18 gm/mol it has the following structure and designation:

COOH

C HH2N

CH

CH3H2C

H3C

2-amino-3-methylpentanoic acidL-

COOH

C NH2H

CH

CH3H2C

H3C

2-amino-3-methylpentanoic acidD-

Cystein-/S/-2-amino-3-mercapto propanioc acid has an empirical formula of C3H7NO2S

with the constituent elements; carbon 29.752%, hydrogen 5.78%, nitrogen 11.570%,

oxygen 26.44% and sophism 26.44%. it has melting point of 683,4k and boiling point

909.64k. The structure and designation of the stereo isomer is the following.

COOH

C HH2N

CH2

SH

2-amino-3-mercaptopropanoic acidL-

COOH

C NH2H

CH2

SH

2-amino-3-mercaptopropanoic acidD-


Lysine-2-6-di -aminohexanoic acids.

COOH

C HH2N

CH2

CH2

CH2

CH2

NH2

2,6-diaminohexanoic acidL-

COOH

C NH2H

CH2

CH2

CH2

CH2

NH2

2,6-diaminohexanoic acidD-

C6H14N2O2Mol. Wt.: 146.188

m/e: 146.106 (100.0%), 147.109 (6.5%)C, 49.30; H, 9.65; N, 19.16; O, 21.89

2.2 NINHYDRIN

Ninhydrin (2-2-Dihydroxylindane -1-3-dione) is a chemical used to detect ammonia or

primary and secondary amines. When reacting with these free amines, a deep blue or

purple color known as Ruhmann’s purple is evolved. Ninhydrin is most commonly used

to detect finger prints, as amines left over from peptides and proteins terminal amines or

lysine residues/ sloughed off in finger prints react with ninhydrin [4].

Ninhydrin is also used in amino acid analysis of proteins. Most of the amino acid are

hydrolyzed and reacted with Ninhydrin except proline; also certain amino acid chains

degraded. There fore separate analysis required for identifying such amino acids that

either react differently or don’t react at all with Ninhydrin. The rest of amino acids are

then quantified calorimetrically after separation by chromatography.


2.2 1 REACTIVITY

O

O

Oninhydrin

Properties

Molecular formula-C9H4O3 density=1.482g/cm3

Molar mass-160.1263g/mog boiling point =338.4oc

Appreance-white powder

The carbon atom of a carbonyl bears a partial positive charge of the central carbon of a 1,

2, and 3;-tri carbonyl is less stable and more electrophilic than simple ketones. In most

compounds a carbonyl is more stable than the dihydroxy /hydrate / form. How ever nine

hydrogen is stable hydrate of the central carbon because this from does not have the

destabilizing effect of adjacent carbonyl partial- positive centers. Indane 1, 2, 3, trione

reacts readily with nucleophiles.

Note that in order to generate the Ninhydrin chromophore, the amine is condensed with a

molecule of Ninhydrin to give as Schiff base. Thus only ammonia and primary amines

can proceed past this step .at this step, there must also be an alpha proton for Schiff base

transfer, so an amine adjustment to tertiary carbon cannot be detected by the ninhydrin

test .the reaction of ninhydrin with secondary amines gives an iminum salt, which is also

colored, and this is generally yellow –orange in color.

2.2.2 The ninhydrin reaction with amino acids and their mechanism

The most important reaction of amino acids is the reactions that are utilized in the

formation of peptides and proteins. Proteins analysis requires determination of the

identity and quantity of each constituted amino acid is the major or step include:

- Hydrolyzing with acids

- Separation with chromatography

- Identification and quantification of the individual amino acids


Ninhydrin which is easily dissolved in ethanol with yellow color solutions reacts with

free alpha amino groups of primary amines and gives blue purple product. The blue

Compound was found to form metal complexes, the blue usually being converted to red.

A 1:2 metal to ligand ratio was suggested [5].

The Ninhydrin reaction is a major method in amino acid analysis. However, the reaction

is not selective. All amino acids, except proline and other amine group containing

compounds also produce the same product. The final product being the same feral the

amino acids, this test does not merit for distinguishing one acid from the other.

There are four important steps is the reactions sequence of Ninhydrin with amino acids:

1. Condensation 3. Hydrolysis

2. Decarboxylation 4. Condensation

From the reactions of 2:1 ratio of ninhydrin to amino acids results in the Ruhmann’s

purple product (look at page 10).


2.2.3 Mechanism reaction of ninhydrin and amino acids

The ketimine (the Schiff base) being of relatively greater potential because it can act ass a

tridentate ligand forming two stable five membered rings on complexation with metal

ions [6, 7]

The stability of these complexes deceases with

- increase in ring size

- increase in the length of the side chain


- Increase in distance between the amino and carboxyl group it also showed that

the complexes are distinctly colored, which is important in identifying and

quantifying amino acids, in addition to the above the length of the amino acid

side chain has an influence on the complexing properties of the amino acid to

wards the common transitional metal ions. [7]

This is the basis for studying the reaction between ninhydrin and a variety of amino acids

in the presence of metal ions, particularly transition metal ions.

The metal complexes are distinctly colored. A specific correlation of metal ion amino

acid colors can thus be developed on the result which can from a basis for amino acid

identification and determination

2.3 Schiff Bases

They are compounds containing an amino or azomethine group (R-C=N-) and are usually

formed by the condensation of a primary amine with an active carbonyl compound. The

reaction to prepare Schiff base is reversible, progressing through a carbine amine

intermediate and requires the removal of water.

Schiff bases which are effective as coordinating ligands have a functional group OHNH2,

SH etc, sufficiently, near the site of condensation so as to form five or six membered

chelating ring on reaction with metal ions

-

CR

R

O + R' NH 2 C NH2+

-O

R

R R'

C

R

R

HO

NH2

+R

C N

R

R

R+H2O

Where R is H and R’ alky aryl OH, NHR and OR group Reaction mechanism for the

formation of Schiff base. Schiff bases have played an important role in the development


of coordination chemistry as they form stable complexes with most of the transition

metals.

In the area of bio-inorganic chemistry, interest on Schiff base metal complexes has been

due to the role such complexes play in providing synthetic models for metal containing

sites in metalloproteinase and enzymes.

A wide variety of ligands may be obtained via the Schiff base condensation reactions

which vary in dent city, flexibility, and nature donor atoms, and in electronic properties.

Metal complexes of Schiff bases have varied geometries and magnetic properties.

Multidentate ligand having oxygen and nitrogen donor system reveal a number of ‘ONN’

and ‘ONO’ donor sequence which have resulted in the formation of multinuclear metal

cheated.

As the chelating function is found in different environment, they are likely to provide a

verity of donor system, like ONN, OO and ONO for efficient metal binding reactions.

2.3.1 Biological Important Of Schiff Base

Schiff base appear to be important intermediates in a number of enzymatic reactions

interaction of enzymes with an amino or a carbonyl group of the sub state .one of the

most prevalent types of catalytic mechanisms in an enzyme to form an imines, or Schiff

base [12]

Stereo chemical investigation carried out with the aid of molecular models showed that

schiff base formed between methylglyoxal and the amino groups of the lysine side chains

of proteins can bend back in such away towards the nitrogen atoms of peptide groups that

a charge transfer can occur between these groups and oxygen atoms of the schiff bases .

In this respect, pyridoxal Schiff bases derived from amino acids have been prepared and

studied. Schiff bases derived from pyridoxal and amino acids are considered very

important ligand from the biological point of view .transition metal complexes of such

ligand is important enzyme models. The rapid development of these ligand are important

and resulted in an enhanced research activity in the filed of coordination chemistry

leading to very interesting, conclusions[8].

Certain polymeric Schiff bases have been reported which possess anti tumor activity .the

schiff bases have the highest degree of hydrolysis at PH= 5 and the solubility in water it is


also high at this PH. The astictumors activity of the bases towards astictumors increases

considerable with slight increase in water solubility .Another important role of Schiff

bases structure is in transmination. Tranaminases are found in mitochondria and cytosal

of eukaryotic cells .All the Tranaminases appear to have the same prosthetic group, i.e.

pyridoxal phosphate, which is non- covalently linked to the enzyme protein.

The biosynthesis of porphyrin,for which glysine is a precursor and another important

pathway ,which involves the intermediate formation of schiff base between keto- group

of one molecules of α-amino acid and α – amino group of lysine residence of an enzyme .

2.3.2 Catalytic applications of Schiff bases

Schiff bases are condensation products of primary amines with carbonyl compounds and

they first reported by Schiff in 1864. The common structural features of these compounds

is the azomethine group with a general formula RHC = N- R’ where R and R ‘ are alkyl

,aryl, cycloalkyl or heterocyclic groups which may be various substituted .these

compounds are also known as imines or azomethine Several studies showered that the

presence of alone pair of electrons in an sp2hybridized orbital of biological importance

.Because of the relative easiness of preparation ,synthetic flexibility ,and the special

property of C=N group, Schiff base are generally excellent chelating agents especially

when a functional group like - OH or –SH is present close to the azomethine group so as

to form a five or six member ring with the metal ion. Versatility of schiff base their

complex makes further investigations in this area highly desirable.

Recent studies showed that transition metal complex of Schiff bases have emerged as

highly efficient in various fields of synthesis and other useful reactions. Synthetic

chemists some times seek imitate the efficiency and elegance of he biosynthetic

machinery by designing biomimetic reactions on path ways. Probably the most

astonishing biometric reactions are processes, which combine several transformations in

sequence and produce complicated structure from comparably simple stating materials, in

a simple laboratory operation.

The role of schiff base catalysts in the synthesis of quality polymers is also equally

important. A serious Schiff base ruthenium complexes which acted as catalysts in the

filed of atom transfer radical polymerization were reported to be synthesized transfer

radical polymerization were reported to be synthesized.


When activated with trimethylsilyl azomethine polymerization of Norborene and

cyclooctene. The activities for both types of reaction were reported to be depending up

on the satiric ,bulk and electron donating ability the Schiff base ligand and optimal

equilibrium in atom transfer radical polymerization could be established adjusting the

steric and electron properties of the a schiff base ligand.

2.4 The chemistry of metal ions

Cobalt always occurs in nature association with nickel. the oxidation of cobalt increased

stability of II to state the III state is the relatively unstable simple , compounds but the

low spin complex are exceedingly numerous and stable , especially where donor atoms (

usually nitrogen)make strong contribution to the ligand field .Cobalt ( II ) forms

numerous complex mostly either octahedral or tetrahedral but five -coordinate square

spices are also known .the tetrahedral complex of Cobalt ( II) are more .This is due to the

fact that for a d7 ion,ligand field stabilization energies disfavor the tetrahedral

configuration relative to the octahedral one to smallest extent that for any other dn

(1<n<9) configuration[9].

The maximum coordination number of nickel (II) is six. nickel ( II) forms a large number

of complex with coordination number three to fix , a considerable number neutral ligands

,especially amines displace some or all of the water molecules in the octahedral Ni(H20)+2

form complexes such as trans Ni(H20)2 (NH3)4)(No3) 2, [NiNH3)6] (Clo4)2 and [Ni(en)3

]SO4 . These complexes are characteristically blue or purple in contrast to the bright green

of the hexa aqua nickel ion. This is because of shift in the observation band when water

ligands are replaced by other ring towards the stronger and of the spectrochemical series

.on the other hand softer ligands, such as phosphors and sulphur ligands, generally have

four coordinate species, with a strong preference for square planar. Nickel does, how

ever, have a tendency to add a further ligand to give five coordinate compounds. Most cu

(II) salts dissolve readily in water and give the aqua ion,

Addition of ligands to such aqua ions solution leads to the formation of complex by

successive displacement of water molecules with NH3, for example the spices [CU (NH3)

(H2O)6] 2+ --- [ cu (NH3)4(H2O )2 ]

2+ are formed in the normal way. Addition of the fifth

NH3 can occur in aqueous solution, but the sixth occur only in liquid ammonia .the

reason for this unusual behavior is connected with the John- Teller effect.


Because of Cu (II) ion does not bind the fifth and sixth ligands strongly (even the H2O)

when this intrinsic weak binding of the fifth and sixth is added to the normally, expected

decreases in the step wise formation constants. Many amine complex of Cu (II are

known ,and all are much more intensely blue than the aqua ion .This is because amines

produces a strong ligand filed ,which case the absorption band for example ,in he aqua

ion the absorption maximum is at -800nm where as in [ CU (NH3) (H2O)2] 2] it is at

~600nm .the reversal of the shifts with increasing take up of NH3 for the fifth ammonia

is to be noted ,indicting again the weaker boding of the fifth ammonia molecule

Zinc forms stable complex with ligands containing N,S,O halides and CN -1 .compounds

of zinc (II ) ions are characteristically diamagnetic ad are color less .the d10 configuration

affords no crystal filed stabilization .stereochemistry of the a particular and satiric

requirements of the ligands .Thus zinc (II ) favors four stage of zinc is 2+ because of its

complete d shell and two additional S electrons .There is no evidence that it is oxidized

or reduced or reduced in biological reactions. It forms planar complexes but many

octahedral complexes are also known the stereochemistry of the zinc (II ) complexes

largely determined by the ligands size ,electrostatic and the type of bonding .Due to

similarity of size ,charge electronic configuration zinc (II ) tends to act as a metabolic

antagonists to zinc (II )[10].

The coordination chemistry of transition metal ions considered in the investigation:

cobalt (II) and nickel (II) will be presented in terms of dn configuration.

2. 4.1 Cobalt II) complexes

Cobalt with a d7 configuration is known four coordinate ( tetrahedral ) and six coordinate

( octahedral ) stereochemistry .the electronic spectra of tetrahedral cobalt ( II) complexes

are intense than those of the octahedral ones[11].

In octahedral cobalt (II) complexes 4T1g and 2A1g are the spin free and spin paired

ground state respectively. For high octahedral geometry, a band near 8000-1000 Cm-1 can

be assigned to 4T1g 4T2g transition A multiple band observe around 2000 cm -1 is

attributed . 4T1g 4T2g transition

The 4T1g 2Eg transition is interesting in that it represents configurationally t2g5

eg2 t2g6eg1 and should be brood and it maximum should shift to lower frequencies


with decreasing temperature, since its energy curve plotted against of has a larger

negative slope than the curve for the ground tern [12]

Some other transitions of CO (II) are 4T1g (F) 4T1g 4T2g, 4T1g 2Eg, 4T1g 4A2g (F) and 4T1g 4T1g (P) which are observed at 8000-9000cm-1 11 000cm-1,1600-

18000cm -1 And 2000 -21000cm-1 respectively.

Tetrahedral complexes of Co (II) with 4A2 ground state are expected to have three

transitions. 4A2 4T2,

4T2 4T1 (F) and 4A2

4T2 (P) low spin square planar

complexes exhibit a narrow band near 8500cm-1 and a stronger bounder band near

20000cm -1.

2.4.2 Nickel (11) complexes

Octahedral Ni (II) complexes with 3A2g ground state are expected to have three spin

allowed transitions. 3A2g 3T1g (F) (7000-13000cm-1) 3A2g

3T1g (F) (1000-

2000cm) and 3A2g 3T1g

(P) (19000-27000cm).

The octahedral usually consist of a bend in the 1R at 8600cm -1 with ~ 2.5, a close pair

of bands in thread (¬14000cm with 1.8) followed by a weaker band (<1) at 18500cm and

a some what stronger (~4 transition in the blue at 25500cm-1 .

In addition, two spin forbidden transitions 3A2g 1E1g And 3A2g

1T2g Are also

observed, the fist near the second spin allowed truncation and the other band between

second and third spin allowed transitions that is approximations around 15400cm -1 and

18500cm-1 respectively.

Tetrahedral Ni (II) complexes with 3T1g ground state, generally exhibit four transitions.

They are 3T1 3A2,

3T1 1E, 3T1

3T1 (P) and 3T2 1T1 (P) the band 3T1

1T1 (P) is a strong the band of high intensity when compared with others.

Square planar Ni (11) complexes have three spin allowed –d bands corresponding to 1A1g 1A2g,

1A1g 1B1g and

1A1g 1 Eg transitions are expected. The square planar Ni (II)

complexes do not have any absorption band below clearly distinguished from octahedral

and tetrahedral complexes [12].


2.5 Objectives and the scope of the present studies

Schiff base and its complexes have a variety of application including biological, chemical

and analytical. Earlier work has shown that some drugs showed increase activity when

administrated as metal chalets rather than as organic compounds. But, recently a

particular attention has given to the synthesis and study of diamino tetra dentate Schiff

and their complexes in addition to this ninhydrin is most commonly used to detect finger

print. Thus synthesizing and characterizing Schiff base and Ruhmann’s purple that are

derived from different amino acid(Glutamine Iso-leucine ,Cystein Lysine) with ninhydrin

will be studied however recent studies were synthesized and characterized.

2.5.1General objective

• To synthesis and characterize schiff base and Ruhmann’s purple

transition metal complexes derived from ninhydrin and amino acids.

2.5.2 Specific objectives

• To identify the synthesized ligand is unidentate or bidentate

ligands.

• To run the UV-visible of the synthesized metal complexes

• To measure the molar conductance of synthesized metal

complexes


CHAPTER THREE

3 Materials and methodology

All chemicals used in this work Ninhydrin, Amino acids likes;isolucine, lysine, cystein

and glutamine, metals salt Co(NO3)2, Ni (NO3)2, Ethanol, chloroform, methanol, distilled

water, Acetone cobalt standard, Nickel standard, perchloric acid .All the chemical used

are analytical graded(BDH)

3.1 Apparatus and instruments

The apparatus we used in these projects are melting point apparatus condenser, mantle

heater, round bottom flask, rotator evaporator beakers, measuring cylinder, ice bath,

desiccators, sunction pump, funnel, filter paper and stirrer

3.2 General procedures

3.2.1 Synthesis of Schiff base derived from cystein with Ninhydrin

0.007 mole of cystein (1gm) was dissolved in 15 ml of absolute ethanol (99.6%) on

heating 0.007 mol of Ninhydrin (1gm) was dissolved in 15ml of ethanol and the above

two solution mixed together.

The ethanolic solution was refluxed for about 3 hours at 60-70 Co The volume of the

solution were reduced to one third by rotatory evaporator. The violet blue solution was

cooled at ice bath (0oC) until it forms a solid crystal. Then the crystal was filtered on

Suction filtration and washed with ethanol and dried over desiccators for further use in

metal complex.

3.2.2 Synthesis of Ruhmann’s purple

Synthesis of Ruhmann’s purple derived from Iso-leucine and Ninhydrin

0.006 mol (7.6 mmol) of Iso- leucin (1gm) was dissolved in 15ml absolute ethanol 0.012

mole of ninhydrin (2gm) was dissolved in 15ml absolute ethanol.

The ethanol solution was mixed and refluxed for 3 hours at 60-70 0Co the volume of the

solution was reduced to one third of the total solution by rotatory evaporator. The purple

color product was filtered on sunction filtration for further use in Ruhmann’s purple

metal complex

Synthesis of ruhmann’s purple derived from lysine and glutamine with ninhydrin


The same procedure were used for the synthesis of Ruhmann’s purple derived from

lysine and glutamine with ninhydrin as that of Iso-leucine and ninhydrin

3.2.3 Synthesis of Schiff base metal complex

3.2 mmol of Schiff base (0.5gm) previously synthesized was dissolved in 15ml of ethanol

and 3mmol metal nitrate salt of Ni (II) and Co (II) of 0.5gm was dissolved in 15ml of

ethanol. The two solutions was mixed and refluxed for2-3hrs 50_60. oc After refluxing

the volume of the solution was reduced to one third and cooled at 0oc the solid crystal

complex was filtered, washed with ethanol and dried in desiccators

3.2.4 Synthesis of Ruhmann’spurple metal complexes

Ruhmann’s metal complexes of Iso leucine and ninhydrin (0.82 mmol) of Ruhmann's

purple (R1) derived from isolation (0.58gm) was measured and dissolved in 15ml ethanol.

4.37 mmol of metal nitrate salt Ni (NO3)2 (0.8gm) was dissolved in 15ml of absolute

ethanol. The solution was mixed and refluxed for 2.5 hours at 65 oc.filtered and stored the

crystal in desiccators .the same ruhmann’s purple (1.6 mmol =lgm) was dissolved in

ethanol and 8.37 mmol of CoNO3)2

1.6 gm was dissolved and the resulting ethanolic solution was mixed and refluxed for

about 2.5 hours at 65 oc .then filtered and stored in desiccators.

Ruhmann’s purple metal complex of glutamine and ninhydrin (0.82mmol) of Ruhmann’s

purple (R2) derived from glutamine and Ninhydrin, 0.5mg was dissolved in 15ml of

absolute ethanol. 4.37 mmol of metal nitrate salt Ni (NO3)2=0.8gm was dissolved in 15ml

absolute ethanol ad the resulting ethanolic solution was mixed another the same

ruhmann’s purple (1.6mmol =1gm was dissolved in ethanol and 8.37 mmol of Co (NO3)2

was mixed and refluxed for 2.5 hrs at 65 oc and reduce the volume by rotary evaporator,

cooled and filtered and washed the crystal with cold ethanol and stored in desiccators

3.2.5 Ruhmann’s purple metal complex of lysine and ninhydrin

1.32 mmol of Ruhmann’s purple derived from lysine and ninhydrin (R3 ) was dissolved

in ethanol and mixed 2.2mmol of Co(NO3)2 =0.4gm ) was dissolved in ethanol and mixed

well .Another the same Ruhmann’s purple( 1.2mmol = 0.7gm ) was dissolved in ethanol

and 2mmol of Ni(NO3)2 was dissolved in the same solvent .The resulting ethanolic

solution was refluxed separately for 2:30 hrs at 65 oc and reduce the volume by rotatory


evaporator. After the volume was reduced it was cooled, filtered and washed the crystal

with cold ethanol and stored in desiccators.

3.3 Characterization of complexes

The complex were Characterized by the following parameters; solubility, melting

decomposition points, conductivity measurement, electronic absorption spectra

(UV_Vis), TLC and AAS

3.3.1 Thin layer chromatography

The completeness of the reaction was tested using thin layer chromatography precoated

with silica gel plates were used for stationary phase and ethanol was used as a mobile

phase. The completeness of the reaction was determined by the appearance of single spot

(blue or violet –blue color that of the reaction between amino acid and ninhydrin.)

3.3.2 Solubility

The Solubility of the complexes was cheeked by various organic solvents: Diethyl ether,

acetone, and methanol, chloroform (CHCl3) Benzene, ethanol by stirring a small amount

of the complex a test tubes

3.3.3 Melting (decomposition points)

The melting point (decomposition points) was determined by placing a finely powdered

sample in a capillary tube and heating by melting point apparatus.

3.3.4 Conductivity measurements

The conductivity measurements were performed using conductometres in acetone, aprotic

solvent having 10-3 M at room temperature (Philip Harris Conductometres)

3.3.5 Electronic absorption spectra

Electronic absorption spectra in the UV- Visible range were recorded in 200-1100nm

using acetone as solvent (SPECTRONIC GENESEYC 2PC)

3.3.6 Flame atomic absorption spectroscopy

Metal complex was pre pared by heating the complex in 5ml of HNO3 and 10ml of

perchloric acid. For sample analysis four series of working standard metal solution were

prepared by dilution of the metal stocks solution with water and reading the absorbance

(Buck Scientific)


CHAPTER FOUR

4 RESULTS

The composition of the complexes are indicated in each case by metal and (R1, R2, R3) or

s or a combination in which R1= Ruhmann’s purple derived from Iso-leucine and

ninhydrin, S = Schiff base of cystein and ninhydrin

R2 = Ruhmann’s purple of ninhydrin and glutamine, R3 = Ruhmann’s purple of Ninhydrin

and lysine .The compositions are judged from the analytical and spectral data which will

be presented and discussed in the following sections

Table-1 melting point of complexes

Complex Color Appearance Yield (%) Mp (dec.t )0c

CoS Shiny white crystalline 50.13 330

NiS Shiny white crystalline 20.9 330

CoR1 red powder 63.4 236

NiR1 Brick read powder 72.4 220

CoR2 red powder 45.5 229

NniR2 Brick read powder 54.3 241

CoR3 Grey powder 79.24 235-244

NiR3 Grey powder 77.6 238-243

Where S is Schiff base

R1=Ruhmann’s purple derived from Iso-leucine and ninhydrin

R2= Ruhmann’s purple of glutamine and ninhydrin

R3=Ruhmann’s purple of lysine and ninhydrin

Solubility test of metal complex Solubility of complexes was checked in acetone, chloroform, ethanol solvents by shaking small amount of the complex in test tube.


Table- 2 Soluble test of complex indifferent solvent Complex Acetone CHCL3 CH3OH COS X X X NIS X X X CoR1 X R2Ni COR2 X NiR2 X COR3 X NiR3 X Where s- Schiff derived form cystein ninhydrin

R1= Ruhmann’s purple of Iso-leucine and ninhydrin


R3=Ruhmann’s purple lysine and Ninhydrin

- Soluble

X – Insoluble

Table -3 – molar conductance values Ruhmann’s purple metal complex.

Complex

Temperature(C0) PH Conductance In acetone Λm Ω

-1 cm2mol - Blank ( acetone ) 27 0.008 - CoR1 27 5.177 0.0075 120 Ni R1 27.3 5.69 0.007 56 COR2 27 5.62 0.0065 34.66 NiR2 27 5.63 0.006 24 COR3 27 5.63 0.0055 17.6 NiR3 27 5.393 0.0055 17.6 R1= Ruhmann’s purple of Iso-leucine and ninhydrin


R3= Ruhmann’s purple lysine and ninhydrin


Table-4 Spectral data of metal complexes of Ruhmann’s purple

Complex Band position (cm-1) ε Assignments CoR1 18518.,20618.6 2130,2200 Bands of the coordinated

azomethine group NiR1 20833.34 1808 d-d transition

CoR2 24691.34,17391.3 2622,2189 Bands of uncoordinated Azomethine group

NiR2 17391.5 1916 The aromatic group CoR3 17543,38,20408.16 2250,2320 d-d transition NiR3 17857.14,20202.02 2240,2320 d-d transition

Atomic absorption spectroscopic studies result

Table - 5 A for Ni complex

No Standard Absorbance

1 0.5ppm 0.03

2 1ppm 0.06

3 2ppm 0.11

4 4mpp 0.22

Table - 5 B for Ni complex

Sample Absorbance Concentration

results

R1Ni 0.041 0.74sppm

R2Ni 0.055 11ppm

R3Ni 0.072 1.3ppm

SNi 0.085 1.54ppm


Table- 5 C for Co-complex Standard Absorbance Concentration 0.5ppm 0.05 - 1ppm 0.09 - 2ppm 0.184 - 4ppm 0.350 0.5ppm Sample = R1Co 0.006 1ppm R2Co 0.092 - R3Co 098 10.8ppm Sco 0.12 1.44ppm


4.2 DISCUSSION

The metal complexes isolation from different amino acids namely: Iso-leucine,lysine

,cystein and glutamine are all distinctly colored , stable to atmospheric condition and are

soluble in organic solvent like methanol and ethanol but only partially soluble in solvents

like chloroform and insoluble in petroleum ether

From table 1 the Schiff base metal complexes of Ni (II) Co (II) that is derived from

cystein and ninhydrin neither melt nor decompose up to 330 oc, while the ruhmann’s

purple metal complexes of Ni (II) and Co (II) that are derived from lysine and Ninhydrin

start melting at a temperature around 236 degree centigrade and also complex of Ni (II)

derived from iso-lecine and ninhydrin which melts at lower temperature around 220 oc

Generally the two ligands prepared are Schiff base ligand which is synthesized from

cystein and ninhydrin and Ruhmann’s purple ligands those synthesized from ninhydrin

and iso-lecine sine and glutamine amino acids .

4.2.1 Molar conductance studies

The molar conductance values were calculated from conductivity measurements in

acetone( aprotic non-polar solvent ).The molar conductance values of the products

obtained from all complexes are very small in the range of 17.6 – 120 Ω-1 cm2mol -1

this shows that they are non_electrolyte nature.

From the above table 3 the conductivity of the metal complexes of ruhmann’s purple is

very low indicates that, these complexes are non- electrolyte and this support,

their neutral nature of the complex and the obtained value suggests that in the

coordination sphere their is no anions present outside

4.2.2 UV-Visible spectroscopic analysis The spectra of transition metal complexes depends on the transition of unpaired electrons

from the ground state to an excited state most of the transition metal complexes are

colored ,a color is observed due to d-d transition in the visible region

The ninhydrin and the amino acid ( Iso-leucin, glutamine , lysine ) from a deep blue

purple colored compound which maximally absorbs at 2469.36 and 17543.36cm-1

The compounds formed via four steps condensation, decarboxylation, hydrolysis and

further condensation.


The electronic specter data of the metal complexes are given in table 4. For CoR3 and

NiR3 complex, the spectral data displays two bands at 17543.38, 20408.16 and 1785.14,

20202.02cm-1. The first band is due to charge transfer.

Avery strong at 2000cm-1Is assigned of π to π* is due to a molecule π bonds with C= O

group and n to π* transition is due to a compound containing an azomethine group (-

CH=N-) which absorbs between 17391.5 -24691.34cm-1

The band between 24691.34 17391.5cm-1Is also associated with the transition of n to π*

this is due to d-d transition of the complex in the region

The literature data reveals that the band around 32000cm-1 and are assigned to the n to π *

transition of the carbonyl group

The electronic spectrum of the metal complexes of Co (II) and Ni (II) complexes show

common bands at 18518.5cm-1 And 20833.34cm-1 which are the characteristics band of

exocyclic azomethine chromophore in the coordination, which in the free state absorbs at

24691.36cm-1 In Ruhmann’s.

The complex prefers a low spin configuration, which is exhibited due to the presence

strong field ligands; such as the azomethine and carbon groups. The Ni (II) complex

exhibited an octahedral geometry with two unpaired electrons.

The valve of magnetic moment obtained corresponds to the literature valve, indicating

the coordination of the metal in an octahedral geometry and the complexes of Co (II) of

the metal in an octahedral geometry with a low spin configuration.

In octahedral cobalt (II) complexes 4T1g and 2A1g are the spin free and spin paired

ground state respectively. For high octahedral geometry, a band near 8000-1000 Cm-1 can

be assigned to 4T1g 4T2g transition A multiple band observe around 2000 cm -1 is

attributed . 4T1g 4T2g transition

4.2.3 Atomic absorption spectroscopy

The determination of Ni (II) and CO (II) concentration.

0.04gram of metal complex of CO (II) and Ni (O) were digesting in 5ml nitric acid and

10ml of perchloricacid. Four serious of Working standard having 0.5,1,2 and 4 ppm were

prepared by appropriate dilution of metal stock solution with distilled water. The

calibration graph (concentration Vs absorbance) was drown in the appendix part.


From this calibration curve, the concentration of the metal ions in the complex are

determined having 93.12% Ni (II) and 90.36% Co (II) were found by composition


5 Conclusions

Metal complexes such as Co(II) and N (II) were synthesized by using the Schiff base and

Ruhmann’s purple formed from by the condensation of ninhydrin with cystein and

ninhydrin with three amino acids like; Iso-Leucine, Glutamine and lysine respectively.

Even if there is an absence of spectrometer instruments such as; IR, NMR,MS that can

provide substantial evidence for determination of structure of the complexes which is

formed from Ninhydrin - amino acids reactions with transition metals such as Co(II)

Ni(II) will be proposed. The following structure will be drawn based on the central view

of the nature of the ligand_metal complex

I) The proposed structure of Ruhmann’s purple with Ni(II) and Co(II)


II The proposed structure for Schiff base with Ni (II) and Co(II).

The complexes formed with Co (II) and Ni (II) is powders in nature and obtained in good

yield. As can be seen from the result data the complexes are distinctly colored; they have

different percentage yields and appearances. The elemental analysis data of the

complexes are given in tables. The analytical data matches with 1:2 metals to Ruhmann’s

purple and1:1schiff base complexes in an octahedral geometry for the complexes of Ni

(II) and Co (II). The molar conductance (Λ m) values were calculated from conductivity measurements of

the solvent (Acetone) and a metal complex in acetone. The molar conductance values of

the products obtained from all the complexes are very small, in the range of 17.6-120Ω-1

cm-2 mol-1. These show their non-electrolyte nature.

Ninhydrin and Iso-Leucine, glutamine or lysine form a deep blue purple colored

compound known as the Ruhmann’s purple, which maximally absorbs at 20833.34 cm-1

The compound is formed via four steps; condensation, decarboxylation, hydrolysis and

further condensation. The electronic spectral data of the metal complexes are given in

table 4. The bands observed at 2000cm-1 and 21691.34 cm-1 in the complexes are

assigned to the π→π * transition of the benzene moiety. The electronic spectrum of the Co (II) & Ni (II) complexes show common bands around 18518.5cm-1 and 20833.34cm-1

which are characteristics bands of the exocyclic azomethine chromopher.


6 Recommendations Our project work concerned with preparation, structural determination & characterization

of Schiff base & Ruhmann’s purple which are the condensed from the reaction of

ninhydrin & amino acids and then complexing this residue with transition metals such

as cobalt & nickel complexes. While we doing our experimental analysis we had been

faced the problem such as lack of IR, H-NMR and C-NMR to know the complete

structure of ligands and complexes. And we were also faced lack of chemicals like

DMSO & DMF to dissolve our complexes. So the structure of the complexes & ligands

was proposed using only UV-VIS spectroscopy & from the theoretical back ground. By

taking into consideration these mentioned and other related problems the concerned

body shall give and provide solution.


7 REFERENCES 1 FAlbert cotton Advanced Inorganic chemistry, 6th edition. 2. Belete Yilma June 2004 , synthesize and characterization of metal complexes, Office

Research and graduate programs, Addis Ababa University.

3. Skoog Holler BIEMAN, principles of instrumental Analysis, 5th edition.

4 Namsun Wang1996, Amino acid Assay by Ninhydrin colorimetric method,

Department of chemical Engineering universities.

5. Ruhmann, 1911, S.J chem. Soc 99, 792.

6 Jolly, W.L preparative inorganic Reactions, Vol.I.

7. Marry, R, KHarpers1996, Biochemisteary, 24th edition; John wiler New York. 8. J. Lewis and R.G Wilk, 1967, Modern coordination chemistry, principles and methods,

New York.

9 J. Lewis and R.G Wilk, 1967, Modern coordination chemistry, principles and methods,

New York.

10. J. Chemsol Dalton, 2001 Trans, 2850-2857.

11 .Bodie Douglas, Darla mc Daniel, John Alexander, 1995 concept and models of

inorganic chemistry, 3rd edition, USA.

12. J.E. Huheer, EA keiter and R.L Keiter, inorganic chemistry, principle of structure

and Reactivity, 4th edition Harper Collins college publisher USA.


8 Appendixes Calculation of the Results Results obtained from Ruhmann’s purple (R1) and ninhydrin with cobalt (II) taken for simplicity 1.Determination of molar conductivity having 10-3M preparation of 10-3M

mole = mass ⁄molecular weight = 193.666

033.0−glmo

=4.95*10-5mol

Conc. = mol ⁄Vol. of soln , where Volume of Solvent (acetone) =50ml

C=λ3

5

10*50

10*95.4−

−

= 0.99*10-3Mol≈*10-3 mollit

M(Ω-1cm2mol-1)=C

k1000

Where M -Molar conductivity K -specific conductance C - Concentration

K= bRR acetone

− 11

where b -call constant=∆λ

R- Resistance

K= 534.8008.0*0075.0

0075.0008.0

008.0

1

0075.0

1 ∩=−=−

M (Ω-1Cm2Mol-1) = 1000*imol

s

λΙ

/10

34.83− ,

=1000*333

9

/10*/10

10*34.8−−−

−

cmititmol λλ where S-Siemens ands=

Ω1

= 10*33

9

/10*

10*34.8

CmlitMol −

−

= CmMol

CmSS 333 10*10*34.8 −

M( )12 01−−Ω ηCm =8.34SCm2η01-1 Determination of concentration of standard sample from Absorbance Measurements 2. Determination concentration of Ruhmann’s (R1) Ni Complex First From the calibration curve the equation must be calculated Y= mx+ b m=Slope x=conc. b- Intercept y =Absorbance of sample


Slope (m) 24

11.022.0

−−=

∆∆

x

Y =0.055

The equation of calibration curve become Y=0.055x (The graph pass through origin) Then from the equation, the concentration of R1 Ni calculated as: 0.041=0.055x

X=055.0

041.0

x=0.745ppm, Determination of concentration of Ruhmann’s (R1) Co (II) complex First From the calibration the equation obtained is Y=Mx+b

Slope =24

184.035.0

−−=

∆∆

x

Y=0.083

The equation of calibration curve become, Y=0.083x (pass through the origin) is the equation calibration curve of R1 Co complex calculated as follow. Y=0.083x, where Y-is the absorbance of R1 Co complex 0.086= 0.083x

X=083.0

060.0=0.722ppm Concentration of R1Co

3. Determine the percentage of the metals in the complexes. From the calibration graph (concentration versus absorbance), the percentage of metals calculated as follow.

M (II) % =Absorbance (A1ppm)* 1000

100*

sampleoftheMass

toedVolumedist

Known Data Concentration of Ni Ri= 0.745ppm Volume diluted to =50ml Mass of the sample (R1Ni) =0.049m

Ni (II) %= 0.745ppm*1000

100*

04.0

50

gm

mλ

Ni (II) % =93.125% • Similarly the percentage of Co(II) in Ruhmann’s (R1) Co Complex Was

calculated as

Co (II) % = Absorbance (∆ppm) *1000

100*

sampletheofmass

todillutedVolume


Known data : Concentration of R1 Co Calculated from absorbance = 0.722ppm Volume diluted to=50ml Mass of the sample (R1Co) = 0.04 gm

Co (II) %= 0.722ppm=1000

100*

04.0

50

gm

ml

Co (II) %=90.36% 4. Percentage yield on of the complexes. The percentage yield of the complexes are determined as

% yield =yieldltheoretica

yieldCtual∆*100

For example the percentage of Ni Ruhmann’s purple complex A Y of complex=0.49M


T.Y of R1Ni can obtained from the limiting Reaction

C

O

O

N

O

O-

+M(II)

O

O-

O-

O

-O

N

2

M

O-

O

N

-O

O

0.5g

0.8g

From this reaction 2:1moleratio of Ruhmann's purple metal complexthe following result was obtained


From this rxn 2:1 mol ration

Ruhmann’s purple with the metal

gm

m

η60

59.0

//71.182

88.0

mog

0.82mmol 4.3mmol The limiting reactant is the Ruhmann’s purple

mol

X

mol

m

/719.6666059

59.0 =

X= m559.0604

)73.666(5.0 =

%Yield= %72100*559.0

49.0100*

/

. ==m

m

YT

YA


Graph of calibration curve

Calibration curve of Ni

y = 0.0553x

R2 = 0.9986

0

0.05

0.1

0.15

0.2

0.25

0 2 4 6

Concentration

Abs

orba

nce

Where; concentration in ppm Absorbance in nm Fig 1; calibration curve of Ni


Calibration curve of Co

y = 0.0553x

R2 = 0.9986

0

0.05

0.1

0.15

0.2

0.25

0 2 4 6

Concentration

Abs

orba

nce

Where ; Concentration in ppm and Absorbance in nm Fig 2; calibration curve of Co

synthesis and characterization of schiff base metal complex

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