Syntheses and characterization of amino and amido-imido technetium(V) and rhenium(V) complexes with (o-aminophenyl)diphenylphosphine-N,P. Crystal structures of [TcNCl{PPh2(C6H4NH2-2)} 2]Cl·MeCN and [Re{PPh2(C6H4N-2)}Cl2{PPh 2(C6H4NH-2}]

Reactions of [NBu4][MOCl4] (M = Tc or Re) or [ReOX2(OEt)(PPh3)2] (X = Cl, Br or I) with the bidentate ligand (o-aminophenyl)diphenylphosphine (H2L) under controlled reaction conditions gave neutral imido-metal(V) complexes of the type [M(L)Cl2(HL)]; in particular, the neutral [Re(L)Cl2(HL)] complex 3, the crystal structure of which has been determined contains HL- and L2- ligands 'twisted' relative to each other by 101.3°, with the imido group bonded trans to a Cl atom, while the other chloro is equatorial. Important molecular parameters are: Re-N(2) 1.780(7), Re-N(1) 1.973(7), Re-Cl(1) 2.404(2), Re-Cl(2) 2.384(2), Re-P(1) 2.438(2) and Re-P(2) 2.492(2) Å. The bent configuration of the imido core [Re-N(2)-C(12) 137.1(5)°] enforced by the intrinsic ligand geometry, along with the v(Re=N-) stretch at 971 cm-1, indicates the peculiarity of this nitrene core. The severe distortion from octahedral geometry is also represented by the Cl(2)-Re-N(2) angle of 157.0(2)° and by the 'bite' angles of 79.5(2) and 75.2(2)° for the HL- and L2- ligand, respectively. Substitution reactions on [NBu4][TcNCl4] and [MNCl2(PPh3)2] (M = Re or Tc) with H2L give cationic nitrido-metal(V) complexes of the type [MNCl(H2L)2]Cl, in which the co-ordination of two bidentate H2L chelates occurs with a mutual cis-P configuration and with the amino-N on the equatorial plane of a distorted octahedron; the site trans to the M?N unit is occupied by a Cl ligand. The crystal structure of [TcNCl(H2L)2]Cl·MeCN 2 has also been determined. Relevant molecular parameters are: Tc-N(3) 1.627(3), Tc-N(1) 2.178(3), Tc-N(2) 2.205(4), Tc-Cl(1) 2.593(2), Tc-P(1) 2.427(2), Tc-P(2) 2.439(1) Å, N(3)-Tc-Cl(1) 179.5(1)°.