spectroscopy: uv spectra miniquiz conclusion unknown 2/ introduction unknown 3: nitro compounds....

Spectroscopy:

UV spectra

MiniQuiz

Conclusion Unknown 2/ Introduction Unknown 3:

Nitro compounds. Inert Compounds.

Today:

Nitro Compounds Typical properties?

Classification test:

Always do with a known compound to compare!

Derivatives (if no other functional group available):

Reduce to amine and then prepare amine derivatives

• Preliminary tests?

• Solubility

• Classification tests

• Derivatives

• Spectra

Iron (II) Hydroxide Test for Nitro GroupsNitro Compounds                                                                                                                                                                               

Carboxylic Acids

IR:

H-NMR:

• Preliminary tests?

• Solubility

• Classification tests

• Derivatives

• Spectra

OH in gas phase(non-H-bonded)

AminesIR

H-NMR

Voodoo Lily

Amorphophallus

Amides

H-NMR:

• Preliminary tests?

• Solubility

• Classification tests

• Derivatives

• SpectraIR?

Unknown 3can be “anything”:

Any of the functional groups of unknowns 1 and 2;also

“Inert compounds”

“Inert Compounds”

Alkanes

Aromatic Hydrocarbons

Alkyl halides. Aryl halides.

Chemical tests and derivatives depend on compound.

• Beilstein test (p.626) for Cl, Br Compare with known compound!

See Chapter in your Lecture text (conjugated systems)

to* HOMO to LUMO

A = x C x l

A = absorbance; = molar absorptivity

C = concentration in mol/L; l = sample pathlength in cm

UV/Visible Spectrophotometry

• Range of UV in nm?

• Which compounds generally absorb in the UV? CH4? CH3(CH2)10CH3? Ethanol? Benzene?

Naphtalene? -Carotene? FeCl3?

• Which compounds absorb in the visible range?CH4? CH3(CH2)10CH3? Ethanol? Benzene?

Naphtalene? -Carotene? FeCl3?

UV/Visible Spectrophotometry

max

Next time:

• Infrared spectrophotometry (IR)

• MiniQuiz on today’s class