The Iminophosphorane Ph3PNSiMe3 as a Synthon for M−Caryl σ Bonds (M = In, Fe, Ge) Implementing Imino Sidearm Donation

Lithiation of triphenyl((trimethylsilyl)imino)phosphorane, Ph 3 P NSiMe 3 ( 1 ), with MeLi gives the ortho-metalated species [Li( o -C 6 H 4 PPh 2 NSiMe 3 )] 2 ·Et 2 O ( 2 ). It has all the requirements of an organometallic ligand capable of sidearm donation: the deprotonated ortho phenyl carbon atom leads to metal−carbon σ bonds in reactions with metal halides, and the Ph 2 P NSiMe 3 moiety donates an electron pair to that metal via the imine nitrogen atom. In reactions with InCl 3 the In(III) organometallic complex [In( o -C 6 H 4 PPh 2 NSiMe 3 ) 3 ] ( 3 ) was obtained, while with FeCl 2 a new example of the rare iron(II) 14-VE complexes [Fe( o -C 6 H 4 PPh 2 NSiMe 3 ) 2 ] ( 4 ) was obtained. Reaction of 2 with Ph 3 GeCl gave [Ph 3 Ge( o -C 6 H 4 PPh 2 NSiMe 3 )] ( 5 ). While in 4 both imino sidearms coordinate to the metal, because of steric crowding only two of the three present coordinate in 3 . Because of the low Lewis acidity of the tetraorganogermanium moiety the imino sidearm does not donate to the central germanium atom in 5 .