Abstract
Ni(cod)(dq) (COD: 1,5-cyclooctadiene; DQ: duroquinone) with an appropriate bipyridine ligand is available for the dehalogenative polycondensation of dihaloarenes to afford -conjugated polymers. The reaction of 2,7-dibromo-9,9-di(n-hexylfluorene) with nickel complex composed of Ni(cod)(dq) and 4,4'-di-tert-butyl-2,2'-bipyridine in DMF/toluene (1:4) proceeded at 120 °C for 72 h. Polyfluorene was obtained in 81% yield with Mn = 13000 (Mw/Mn = 2.0). Ni(cod)(dq) was found to be stored under an ambient atmosphere at room temperature and the use of which after several month vs. a freshly opened nickel complex resulted to afford the corresponding polymer in a comparable yield and molecular weight. Other dihal-oarenes such as fluorene with different alkyl chain structures, 1,4- and 1,3-dihalobenzenes, 5,5'-dibromo-2,2'-bithiophene, and 2,6-dibromo-cyclopentadithiophen also underwent the dehalogenative polymerization to afford the corresponding conjugated polymers in excellent yields with an appropriate degree of polymerization.
