A Sodium Supported Borate Ester: Synthesis, Spectral Characterization and Crystal Structure of dimeric Sodium Organoborate Complex [Na(py)][B(hyncaH−2)2

Abstract

A dimeric sodium supported borate complex, [Na(py)][B(hyncaH−2)2]2 (1) (py = pyridine, hynca = 1-hydroxynaphthalene-2-carboxylic acid), has been synthesised by the reaction of NaBH4 with two equivalents of hynca in anhydrous THF and following crystallization from py/H2O solution afforded borate ester derivative. The complex has been fully characterized by FT-IR in the solid state and by NMR (1H and 13C) spectroscopy and electrospray ionization mass spectrometry in solution. The molecular structure of the title compound was determined by single crystal X-ray diffraction. Structure analysis of complex 1 confirmed the presence of an anionic complex [B(hyncaH−2)2]− in which boron atom is coordinated simultaneously by two hynca ligands utilising both alkoxide and carboxylate groups for bonding. The Na atom is six- coordinate to five O atoms of hydroxy carboxylic acid and one pyridine N atom. Crystal data: crystal system, monoclinic, a = 10.971(3) A, b = 6.839(3) A, c = 30.545(5) A, β = 92.20(2)°, space group P21/c (#14), V = 2,290(1) A3, Z = 4. There are limited examples of alkali metal supported borate ester complexes.