Polysilsesquioxane (POSS)-linked Imidazole-based Carbene and Phosphine Ligands for Transition Metal Catalysts

摘要

Polyhedral oligomeric silsesquioxanes (POSS) linked ligand of the general formula (I)         L [(R^1a)_n-1(SiO_1,5)_n R^2a ]_k [(R^1b)_n-1SiO_1,5)_n R^2b ]_l [(R^1c)_n-1SiO_1,5)_n R^2c ]_m     (I)in which (R^1a,b,c)_n-1(SiO_1,5)_n is a polyhedral oligomeric silsesquioxanes (POSS) with n = 4, 6, 8,10, 12, 14, 16 or 18 andR^1a, R^1b,R^1c is each independently selected from the group consisting of same or different branched or linear C₁-C₂₀ alkyl chains, cyclo alkyl, C₁-C₂₀ alkoxy, aryl, aryloxy, heteroaryl and arylalkyl groups,k, I, m is 0 or 1 provided that k+l+m ≥ 1,R^2a, R^2b, R^2c is a spacer that binds the polyhedral oligomeric silsesquioxane (POSS) to the ligand L and ligand L is an uncharged electron donor.