Synthesis and characterization of d(2) imido complexes of molybdenum. Crystal structure of [MoCl2{N(mes)}(PhC CPh)-(PMe3)(2)]center dot O.5PhC equivalent to CPh (mes = 2,4,6-trimethylphenyl)

摘要

The compound [MoCl2{N(mes)}(PMe3)(3)]1 (mes = 2,4,6-trimethylphenyl) has been prepared by the reaction of [MoCl3{N(mes)} (dme)] (dme = 1,2-dimethoxyethane) with 2 equivalents of PMe3 and subsequent sodium amalgam reduction, in the presence of 1 additional equivalent of PMe3. Metathesis reactions of 1 with KX gave [MoX2{N(mes)} (PMe3)(3)] (X = Br 2 or NCS 3), whereas the anionic bidentate (PrOCS2-)-O-i ligand produced the monophosphine compound [Mo {N(mes)} (S2COPri)(2)(PMe3)] 4. Substitution of two of the PMe3 ligands to give [MoCl2{N(mes)}(PMe3)(depe)] 5 (depe = Et2PCH2CH2PEt2) is also feasible, whilst phosphites and other accepters provided the corresponding [MoCl2{N(mes)} L(PMe3)(2)] compounds [L = P(OMe)(3) 6, P(OCH2)(3)CCH2CH3 7, C2H4 8, H2C=CHCO2Me 9, CO 10, CNBut 11, CNMe 12, PhC=CH 13 or PhC=CPh 14] by substitution of the unique PMe3 group of 1. Some of these arylimido complexes exhibit dynamic behaviour in solution, due to restricted rotation of the aryl group around the C-N bond. The molecular structure of 14 (as its PhC=CPh hemisolvate, ie. 14.0.5PhC=CPh) has been determined by an X-ray study. [References: 53]