Oxonitrates VO(NO3)3 and MoO2(NO3)2 and nitronium and nitrosonium nitratometallates as nitrating agents

Abstract

Dissolution of vanadium in anhydrous HNO3 followed by exposure of the solution in a dessicator over P2O5 gave liquid vanadyl trinitrate (I). The X-ray diffraction analysis of I was carried out for a single crystal grown on cooling the liquid in a sealed capillary. The structure is composed of VO(NO)3 molecules in which the V atom has an unusually high C.N. 7; it coordinates the terminal O atom and three bidentate nitrate groups to form a distorted pentagonal bipyramid as the coordination polyhedron with the terminal O atom occupying one axial vertex. Using the GAMESS program package, ab initio calculation of the structure of VO (NO3)3 in the liquid phase was carried out. It was shown that in all three physical states, vanadyl trinitrate retains its molecular structure almost invariable. Toluene and naphthalene nitration using I and (NO2)[Fe(NO3)4], NO[Cu(NO3)3], (NO)3/4(NO2)1/4[Zr(NO3)5], and MoO2(NO3)2 proceeds at high rates at low temperatures to give an unusually high para-nitrotoluene percentage in the products as compared with the ortho-isomer. The activity of the studied compounds in the nitration of naphthalene decreases in the series VO(NO3)3 > (NO)3/4(NO2)1/4[Zr(NO3)5] > MoO2(NO3)2.