Phosphine induced migratory CO insertion into the Fe-CH_2 bond of the organometallic polymer -[(η~5-C_5H _4)Fe(CO)_2CH_2SiMe_2]_n- and characterization of model iron complexes

摘要

Thermal and photochemical treatment of 1-sila-3-ferracyclobutane, (η~5-C_5H_4)Fe(CO)_2CH _2SiMe_2 (1) results in ring-opening polymerization (ROP). Phosphine-induced migratory CO insertion into the Fe-CH_2 bond of the preformed polymer, -[(η~5-C_5H_4)Fe(CO) _2CH_2SiMe_2]_n- (2) results in either linear polymers, -[(η~5-C_5H_4)Fe(CO)(PR _3)C(O)CH_2SiMe_2]_n- [R_3 = Me_2Ph (3), Ph_3 (4)] or diphosphine bridged polymers, -{[(η~5-C_5H_4)Fe(CO)C(O)CH _2SiMe_2]_2(P-P)}_n- [P-P = dppe (5), dppp (6), dppb (7), trans-dppen (8), dmpe (9); dppe = 1,2-bis(diphenylphosphino) ethane, dppp = 1,2-bis(diphenylphosphino)propane, dppb = 1,2- bis(diphenylphosphino)butane, cis-dppen = cis-1,2-bis(diphenylphosphino) ethylene, dmpe = 1,2-bis(dimethylphosphino)ethane]. The analogous model complexes, {[(η~5-C_5H_5)Fe(CO)C(O)CH _3]_2P-P} [P-P = dppp (10), dppb (11), trans-dppen (12), dmpe (13)] were synthesized and characterized as models of the acylated polymers. The X-ray crystal structure of 11 and 13 were determined to establish the bridging nature of the diphosphines in the model complexes and to get insight of the crystal packing.