Nonstoichiometric Stille Coupling Polycondensation for Synthesizing Naphthalene-Diimide-Based π-Conjugated Polymers

Abstract

A nonstoichiometric Stille coupling polycondensation was first succeeded between 2,5-bis-(trimethylstannyl)thiophene (1) and 4,9-dibromo-2,7-bis(2decyltetradecyl)benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (2) with ratios ranging from 1:1 to 1:10. The model reaction using 2-(tributylstannyl)thiophene (3) and 4,9dibromo-2,7-bis(2-hexyl)benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (4) at a 1:1 molar ratio in the presence of catalytic Pd 2 (dba) 3 /P(o-tolyl) 3 indicated that the rate constant of the second substitution reaction (k 2 ) is 15 times higher than that of the first one (k 1 ). It was found that the selective intramolecular catalyst transfer was promoted by the naphthalene-diimide (NDI) skeleton. The results also provided a new one-pot symmetrical end-functionalization method to synthesize an NDI-based n-type polymer with NDI groups at both α,ω-chain ends.

Alternating Intramolecular and Intermolecular Catalyst‐Transfer Suzuki–Miyaura Condensation Polymerization: Synthesis of Boronate‐Terminated π‐Conjugated Polymers Using Excess Dibromo Monomers

“…The M w / M n value in unstoichiometric polymerization was somewhat narrower than that in stoichiometric polymerization in Tables and except for Entry 6 in Table . A similar tendency was also observed in unstoichiometric Stille polycondensation . However, Nomura observed the opposite tendency.…”

“…In polymerization of the reverse combination of monomers (Ar 1 is acceptor, and Ar 2 is donor in Scheme ), however, the Pd catalyst would be prone to move back to donor Ar 2 after reductive elimination, and intermolecular oxidative addition of 1 to the Pd catalyst on Ar 2 would take place, resulting in conventional condensation polymerization with excess dibromo monomer to afford low‐molecular‐weight polymer. In the reported unstoichiometric Stille condensation polymerization, excess of acceptor dibromonaphthalenediimide was polymerized with donor distannylthiophene, which is the reverse combination of monomers compared to our case. The expanded conjugated system of naphthalenediimide might be account for the stronger affinity for the Pd catalyst, compared to that of donor thiophene.…”

Effects of PNDIT2 end groups on aggregation, thin film structure, alignment and electron transport in field-effect transistors

“…This behaviour is initially unexpected given precisely controlled stoichiometries, but it can be explained by a ring walking behaviour of the Pd catalyst on the NDI unit, which first leads to PNDIT2 prepolymers that are mainly terminated by T2-H at either side. 32 Nevertheless, despite their partial occurrence, NDI-OH and NDI-tolyl chain termini for PNDIT2 made in MeTHF and tol, respectively, represent the only measurable difference in molecular structure. Fig.…”

Additive-controlled Switching from Abnormal to Normal Unstoichiometric Suzuki–Miyaura Polycondensation for Poly(biphenylenevinylene)

“…7 In these polycondensations, the occurrence of either normal or abnormal unstoichiometric polycondensation is dependent on the nature of the monomers and catalysts, and therefore the possibility that both normal and abnormal unstoichiometric polycondensations of the same monomers might be achieved simply by changing the polymerization conditions is an intriguing one. Such switching of the polymerization mode would allow us to control the molecular weight and the chain end groups of polymers obtained by polycondensation of AA and BB monomers.…”