nickel-catalyzed polymerizations: mechanistic studies & new reaction development anne j. mcneil

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Nickel-Catalyzed Polymerizations: Mechanistic Studies & New Reaction Development Anne J. McNeil Department of Chemistry and Macromolecular Science and Engineering Program University of Michigan, Ann Arbor, MI 48109-1055 Conjugated polymers (CPs) are the active components of numerous emerging technologies, including photovoltaics, PLEDs, and sensors. C 6 H 13 O OC 6 H 13 C 8 H 17 C 8 H 17 S C 6 H 13 N C 6 H 13 Traditionally CPs are synthesized via step-growth methods. Chain-growth methods for preparing CPs were discovered simultaneously by Yokozawa and McCullough in 2004. However the scope is limited. We are using a combination of rate and spectroscopic studies to elucidate the mechanism of polymerization so it can be generalized to a wider variety of substrates and applied to the synthesis of new polymer microstructures. Br Br R R Ni P P Br Br R R Ph Ph Ph Ph Ni P P Ph Ph Ph Ph Ni P P Ph Ph Ph Ph Ni P P Ph Ph Ph Ph S S Br Br R R S S R R Br R ate Determining S tep Br Ni Br P P Br R Ph Ph Ph Ph Fast R ate Determining S tep Ni Br P P Ph Ph Ph Ph S Br R Fast Observed by 31 P NMR Spectroscopy Observed by 31 P NMR Spectroscopy Key Results from First Year of Funding Initial Rate [Monomer] C 6 H 13 O OC 6 H 13 Br M gC l S C 6 H 13 Br ClM g 31 P NMR spectrum of Ni(II)-biaryl 31 P NMR spectrum of Ni(II)aryl(halide) Rate studies showing the reaction is zero order in monomer Conjugated Polymers 2004 - McCullough and Yokozawa 2006 - Yokozawa S C 6 H 13 Br ClM g N i(dppp)C l 2 S C 6 H 13 C 6 H 13 O OC 6 H 13 OC 6 H 13 C 6 H 13 O M gCl*LiCl Br N i(dppe)C l 2

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Initial Rate. [Monomer]. Nickel-Catalyzed Polymerizations: Mechanistic Studies & New Reaction Development Anne J. McNeil Department of Chemistry and Macromolecular Science and Engineering Program University of Michigan, Ann Arbor, MI 48109-1055. - PowerPoint PPT Presentation

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Page 1: Nickel-Catalyzed Polymerizations: Mechanistic Studies & New Reaction Development Anne J. McNeil

Nickel-Catalyzed Polymerizations: Mechanistic Studies & New Reaction DevelopmentAnne J. McNeil

Department of Chemistry and Macromolecular Science and Engineering ProgramUniversity of Michigan, Ann Arbor, MI 48109-1055

Conjugated polymers (CPs) are the active components of numerous emerging technologies, including photovoltaics, PLEDs, and sensors.

C6H13O

OC6H13

C8H17C8H17

S

C6H13

N

C6H13

Traditionally CPs are synthesized via step-growth methods. Chain-growth methods for preparing CPs were discovered simultaneously by Yokozawa and McCullough in 2004. However the scope is limited.

We are using a combination of rate and spectroscopic studies to elucidate the mechanism of polymerization so it can be generalized to a wider variety of substrates and applied to the synthesis of new polymer microstructures.

Br

Br

R

R

NiP

P

Br

BrR

R

Ph Ph

Ph Ph

NiP

P

Ph Ph

Ph Ph

NiP

P

Ph Ph

Ph Ph

NiP

P

Ph Ph

Ph Ph

S

S

Br

BrR

R

S

S

R

R Br

Rate Determining

Step

Br

NiBrP

P

BrR

Ph Ph

Ph Ph

Fast

Rate Determining

StepNi

BrP

P

Ph Ph

Ph Ph

S

BrR

Fast

Observed by 31P NMR Spectroscopy

Observed by 31P NMR Spectroscopy

Key Results from First Year of Funding

Init

ial

Rat

e

[Monomer]

C6H13O

OC6H13Br

MgCl

S

C6H13

BrClMg

31P NMR spectrum of Ni(II)-biaryl

31P NMR spectrum of Ni(II)aryl(halide)

Rate studies showing the reaction is zero order in monomer

Conjugated Polymers

2004 - McCullough and Yokozawa

2006 - Yokozawa

S

C6H13

BrClMg Ni(dppp)Cl2 S

C6H13

C6H13O

OC6H13OC6H13

C6H13O

MgCl*LiClBrNi(dppe)Cl2