名称:
Complexes of MoO2Cl2 and WO2Cl2 with the ligands N,N,N′,N′-tetramethylethylenediamine, N,N′-di-t-butyl-1,4-diaza-1,3-butadiene and N,N′-dimethylpiperazine. cis,trans,cis vs all cis coordination in bidentate N-donor complexes of WO2Cl2 and MoO2Cl2. Crystal structures of MoO2Cl2(N,N,N′,N′-tetramethylethylenediamine) and MoO2Cl2(N,N′-DI-t-butyl-1,4-diaza-1,3-butadiene)
摘要:
The complexes [MoO2Cl2(But-dab)], [WO2Cl2(But-dab)] (But-dab = N,N'-di-t-butyl-1,4-diaza-1,3-butadiene), [MoO2Cl2(dmp)] and [WO2Cl(dmp)] (dmp = N,N'-dimethylpiperazine) have been prepared and characterized by IR, Raman, H-1 and C-13 NMR spectroscopy. [MO2Cl2(dmp)] (M = Mo, W) has cis-dichloroligands and [MoO2Cl2(dmp)] shows fluxional behaviour of the coordinated ligand in CH2Cl2 solution, as monitored by H-1 NMR spectroscopy. The structures of [MoO2Cl2(tmen)] (tmen= N,N,N',N'-tetramethylethylenediamine) and [MoO2Cl2(But-dab)] are reported. Both compounds are built up of discrete molecules with distorted octahedral geometry and cis-dioxoligands, the former having the unusual cis-dichloro and the latter the common trans-dichloro arrangement. MoO2Cl2(tmen) has Mo=O distances of 1.681(4) and 1.697(4) angstrom with an O-Mo-O angle of 103.1(2)-degrees. The trans influence of the oxo-ligands is shown by two different Mo-Cl distances [2.449(2) angstrom trans to O and 2.338(2) angstrom trans to N] and two different Mo-N distances [2.464(4) angstrom trans to O and 2.278(4) angstrom trans to Cl]. MoO2Cl2(But-dab) has an Mo=O distance of 1.688(3) and an O-Mo-O angle of 104.5(2)degrees. The trans-dichloro ligands have equal distances to molybdenum, d(Mo-Cl) = 2.356(1) angstrom. The Mo-N distances of the nitrogen atoms trans to the oxo groups are 2.399(2) and 2.388(2) angstrom.
DOI:
10.1016/s0277-5387(00)81728-3