Dinitrosylvanadiumkomplexe: [VL₄(NO)₂]Br (L = N, P, As, Sb, O und S-Donor/Akzeptor) und [VX(CNR)₃(NO)₂] (X = Cl, Br, I) / Dinitrosylvanadium Complexes: [VL₄(NO)₂]Br (L = N, P, As, Sb, O and S Donor/Acceptor) and [VX(CNR)₃(NO)₂] (X = Cl, Br, I)

Abstract

The reaction between [V(THF) 4 (NO) 2 ]Br and various ligands {L} with a N , P. As, Sb, O and S donor/acceptor function leads to the complexes [V(THF) 4-n {L} n (NO)i]Br, where n = 4 [P(OMe) 3 , Me 2 P(CH 2 ) 2 PMe 2 , {N }, {O }, {S}], n = 2 and 3 [{P}, AsEt 3 , SbEt 3 ], and n = 1 [P(OMe) 3, AsEt 3 , SbEt 3 , Ph 2 P (CH 2 ) 3 PPh 2, Ph 2 As(CH 2 ) 2 PPh 2 ]. The constitution of the compounds is established on the basis of 51 V NMR characteristics [(δ( 51 V) and 1 J( 51 V - 31 P)]. The two NO groups occupy cis positions (IR evidence). With isonitriles, [V(THF) 4 (NO) 2 ]X yields the neutral complexes [VX(CNR) 3 (NO) 2 ] as the main products, which exhibit a normal halogen dependence (X = Cl < Br < I) of 51 V shielding. δ( 51 V ) values span a range from +296 (L = THF) to -1100 ppm [½ L = Me 2 P(CH 2 ) 2 PMe 2 ] relative to VOCl 3 . Shielding of the 51 V nucleus decreases in the order PR 3 ≈ CNR > {N } > {S} > {O }; en > dipy. phen > diazadiene > NCR > py > NH 2 Ph; OPR 3 > OSMe 2 > OCR 2 > THF; and PMe 3 > SbEt 3 ≈ AsEt 3 ≈ -PPh 2 > - AsPh 2 . This ordering reflects (counteracting) trends in the polarizability and the π acceptor ability of the ligands. An effect caused by the chelate ring size (5-ring > 6-ring > 4-ring) is also observed and reflects torsional and ring strains.