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