Synthesis and investigation of the configurational stability of some dimethylammonium borate salts

Abstract

Two borate salts, dimethylammonium bis[3-isopropylbenzene-1,2-diolato(2−)-O,O′]borate and dimethylammonium 3,3′′-ethylenebis(3′-methylbiphenyl-2,2′-diolato(2−)-O,O′)borate, were synthesised from the corresponding catechol and tetraphenol respectively. The configurational stability of these salts was determined by variable temperature 1H NMR spectroscopy; the activation energies for the racemisation process were determined to be 85 and 79 kJ mol−1 respectively. Mechanisms are proposed to explain the configurational instability observed.