Synthesis, structure and NMR of cis-dioxotungsten (VI) complexes with 2-methoxypyridine and 2,3-dihydroxynaphthalene bidentate ligands

Abstract

Two novel cis-dioxotungsten (VI) complexes, [WO 2(L a) 2](1) and [WO 2(L b) 2R 2Pr](2) [L a=2-methoxypyridine, L b=2,3-dihydroxynaphthalene, R=the six-member ring ion (C 5H 11N 2), Pr=1,3-propanediamine] have been synthesized and characterized by X-ray crystallography, 1H, 13C NMR and IR spectra. It is found that the tungsten atom is coordinated in a pseudo-octahedral fashion by two cis–oxo functions. The complex 1 is a neutral molecule, which is packed in crystal lattice via O⋯H–C hydrogen bonds and π–π interactions while there are two six-member ring cations (C 5H 11N 2) to compensate the negative charge of [W(VI)(OC 10H 6O) 2] 2− anion in complex 2. The new molecules of C 5H 11N 2 are the by-products produced by the protonated 1,3-propanediamine and ethanenitrile.