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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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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