Synthesis, chemistry and structures of complexes of the dioxovanadium(V) halides VO2F and VO2Cl

VO2F(L-L)] (L-L = 2,2'-bipyridyl, 1,10-phenanthroline, Me2N(CH2)2NMe2) and VO2F(py)2] (py = pyridine) have been prepared from the corresponding VOF3(L-L)] or VOF3(py)2] and O(SiMe3)2 in MeCN solution. VO2F (itself made from VOF3 and O(SiMe3)2 in MeCN) forms Me4N]VO2F2] with Me4N]F, but does not react with neutral N- or O-donor ligands. VO2Cl, prepared from VOCl3 and ozone, reacts with 2,2'-bipyridyl or 1,10-phenanthroline to form VO2Cl(L-L)], with pyridine or pyridine-N-oxide (L) to produce VO2Cl(L)2], and with OPPh3 or OAsPh3 (L') gives VO2Cl(L')]. A second product from the OPPh3 system is the ionic VO2(OPPh3)3]VO2Cl2] containing a trigonal bipyramidal cation. Neither VO2F nor VO2Cl form isolable complexes with MeCN, thf or MeO(CH2)2OMe, and both are reduced by P-, As-, S- or Se-donor ligands. Ph4As]VO2X2] (X = F or Cl) react with 2,2'-bipyridyl to form VO2X(2,2'-bipyridyl)], but similar reactions with weaker O-donor ligands fail. The complexes have been characterised by IR, multinuclear NMR (1H, 19F, 51V or 31P) and UV-visible spectroscopy. X-ray crystal structures are reported for VO2F(py)2], VO2Cl(L)2] (L = py or pyNO) and VO2(OPPh3)3]VO2Cl2].