Matthew Hannigan
Michigan
A Surprising Ni Oxidative Addition into a C-S bond, and its Implications for Catalyst Transfer Polymerization with Complex Monomers
Conjugated polymers containing complex, multi-arene monomers are among the highest performing materials used in organic solar cells. Currently, these polymers can only be synthesized via step-growth methods which often give high dispersity and little control over molecular weight compared to alternative chain-growth methods, such as catalyst transfer polymerization (CTP). Attempts to synthesize a potentially high performing material, poly(thieno[3,2-b]thiophene), using CTP with Ni catalysts have failed, and studies have proposed this failure is because thieno[3,2-b]thiophene forms a persistent π-complex that prevents CTP from continuing. Instead, our recent computational and experimental studies on thieno[3,2-b]thiophene π-complexes show that an oxidative addition into the carbon-sulfur bond of thieno[3,2-b]thiophene is likely the reason for the inability of CTP to proceed, rather than a persistent π-complex. This poster will highlight our efforts to prevent this trapped species from forming via changes in ligand structure and metal identity. Understanding this trapped species will allow us to gauge the feasibility of using CTP for synthesizing next generation materials, and could allow for more facile synthesis of many materials used in organic solar cells.
Conjugated polymers containing complex, multi-arene monomers are among the highest performing materials used in organic solar cells. Currently, these polymers can only be synthesized via step-growth methods which often give high dispersity and little control over molecular weight compared to alternative chain-growth methods, such as catalyst transfer polymerization (CTP). Attempts to synthesize a potentially high performing material, poly(thieno[3,2-b]thiophene), using CTP with Ni catalysts have failed, and studies have proposed this failure is because thieno[3,2-b]thiophene forms a persistent π-complex that prevents CTP from continuing. Instead, our recent computational and experimental studies on thieno[3,2-b]thiophene π-complexes show that an oxidative addition into the carbon-sulfur bond of thieno[3,2-b]thiophene is likely the reason for the inability of CTP to proceed, rather than a persistent π-complex. This poster will highlight our efforts to prevent this trapped species from forming via changes in ligand structure and metal identity. Understanding this trapped species will allow us to gauge the feasibility of using CTP for synthesizing next generation materials, and could allow for more facile synthesis of many materials used in organic solar cells.