Terminal Phosphido Ligand Complexes

Structure and Bonding of Terminal Phosphido Ligand Complexes... 

Trialkoxy complexes of tungsten with terminal phosphido ligands could not yet be isolated. They were postulated to be very reactive intermediates in different transformation reactions, e.g., during the metathesis reaction of [W2(0R)6] with phosphaalkynes [6, 14]. However, we were able to characterize the complex [(t-BuO)3W=P] (3c) by P-NMR spectroscopy by monitoring the metathesis reaction of [W2(Ot-Bu)6] with MesC=P in the tempera-... 

Metathesis routes have been used to prepare terminal amido, phosphide, and thiolato complexes (equations 8 10) from Cp 2AnCl2 starting materials. For the bulky bis(trimethylsilyl)phosphido ligand, only mono substitution occurs. 

Large numbers of derivatives are formed by displacement of CO by other ligands (see equations 23.25-23.28 and discussion). Whereas substitution by tertiary phosphine ligands gives terminal ligands, the introduction of a secondary or primary phosphine into a multinuclear carbonyl complex creates the possibility of oxidative addition of a P—H bond to a second metal centre and the formation of a bridging phosphido ligand (reaction 23.54). 

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