Metal complexes containing ‘inorganic (carbon-free) chelate rings.’ Reactivity of the [ReO]3+ core toward bis(diphenyl-phosphino)amine derivatives. Crystal structures of [ReOCl2{N(XPPh2)2}(PPh3)](X = O or S) and [ReO(OEt)-{N(SPPh2)2}2]

Abstract

The complexes [ReOCl₃(PPh₃)₂] and [ReOCl₂(OEt)(PPh₃)₂] react with an excess of NH(OPPh₂)₂ to give [ReOCl₂{N(OPPh₂)₂}(PPh₃)]1. When the donor atoms are changed by using NH(SPPh₂)₂ as the ligand the mono- and di-substituted complexes [ReOCl₂{N(SPPh₂)₂}(PPh₃)]2 and [ReOCl-{N(SPPh₂)₂}₂]3a are obtained. Complex 3a can also be prepared by using the anionic compound [ReOCl₄]^– as the starting material. When complex 3a is crystallized from CH₂Cl₂–EtOH, [ReO(OEt){N(SPPh₂)₂}₂]3b is obtained. The structures of complexes 1,2 and 3b were determined by X-ray crystallography. Compound 1 is triclinic, space group P, with a= 14.885(5), b= 13.815(5), c= 10.019(5)Å, α= 92.35(3), β= 108.46(3), γ= 99.10(3)° and Z= 2. The structure was refined to R= 0.028, based on 4204 observed reflections. Compound (2) is triclinic, space group P, with a= 16.831(5), b= 14.667(5), c= 9.918(5)Å, α= 99.48(3), β= 104.93(3), γ= 92.57(3)° and Z= 2. The structure was refined to R= 0.038, based on 5955 observed reflections. Compound 3b is trinclinic, space group P, with a= 10.214(5), b= 10.750(5), c= 13.947(4)Å, α= 111.72(3), β= 113.07(3), γ= 64.06(3)° and Z= 1. The structure was refined to R= 0.063, based on 4062 observed reflections. All three compounds show slightly distorted octahedral geometries. The chlorine atoms are trans in 1 and cis in 2. The Re–O(oxide) bonds show some triple bond character, and exert a strong trans influence.