X-ray and NMR studies of a diammonium (nitrilotriacetato)dioxovanadate(V) complex

摘要

A new vanadium(V) complex, diammonium (nitrilotriacetato)dioxovanadate(V) (NH4)(2) [VO(2)NTA], has been synthesized. The structure of the complex has been studied by solution and solid-state NMR spectroscopies as well as single crystal X-ray crystallography. It is confirmed from NMR studies that the octahedral geometry is retained in both solution and solid-state of the complex. The chemical exchange between glycinate rings cis to and trans to V=O bond in the complex has been observed in the solution C-13 NMR spectra at elevated temperatures. Large V-51 chemical shift anisotropy (Delta delta(aniso) = -800 ppm) and quadrupole coupling (e(2)qQ/h = 8.80 MHz) were observed in V-51 spectra of the solid complex. Distortion of octahedron also results in an increase of the electric field gradient at a V nucleus. The NMR spectra are discussed on the basis of the crystal structure. (C) 1997 Elsevier Science Ltd. [References: 28]