REACTIVITY OF μ-H)Os_3(CO)_7(μ-2,3-η~2-C=NCH=CHNCH=CH_2)(η~1- CH=NCH=CHNCH=CH_2){μ_3-η~2-PPhCH_2PPh(C_6H_4}= AND Os_3(CO)_8 (μ-2,3-η~2-C=NCH=CH NCH=CH_2)(η~1-CH=NCH=CHNCH=CH_2)(μ_3-η~2-PPhCH_2Ph_2) WTIH P(OMe)_3

摘要

Diphosphine ligands play an important role in organometallic and coordination chemistry, owing to their ability to stabilize a great variety of metal complexes as well to their application in homogeneous catalysis. The synthesis and reactivity of the bridging dppm triosmium compound Os_3(CO)_(10)(μ-dppm) 1 and its orthometallated derivative (μ-H)Os_3(CO)_8{Ph_2PCH_2PPH(C_6H_4)} 2 have widely been studied in recent years because of their novel reactivities to give many interesting compounds. In the course of our research directed toward the reactivity of compound 1 we have recently reported that it reacts with 1-vinylimidazole at 110℃ to yield two novel triosmium compounds (μ-H)Os_3(CO)_7(μ-2,3-η~2-C = NCH = CHNCH = CH_2) (η~1-CH=NCH=CHNCH=CH_2){μ_3-η~2-PPhCH_2PPh(C_6H_4} 3 and Os_3(CO)_8(μ-2,3-η~2-C=NCH=CHNCH=CH_2)(η~1-CH=NCH=CHNCH=CH_2)(μ_3-η~2-PPhCH_2Ph_2) 4 bearing two vinylimidazole ligands in different coordination modes, one orthometallated vinylimidazole derived ligand and the other η~1-coordinated vinylimidazole ligand. The η~1-coordinated nitrogen ligands were found to be very labile and can be displaced by other two electron donor ligands such as phosphines, phosphites and isocyanides. Following this observation we have investigated the reactions of both 3 and 4 with P(OMe)_3. The objective was to examine the lability of the η~1 -coordinated vinylimidazole ligands in these complexes.