Thermodynamics for complex formation of boric acid and borate with hydroxy acids and diols

•1:1 complex is enthalpically formed in both hydroxy acid and polyol systems.•Despite different dehydration numbers, ΔH° values of two systems are comparable.•Intramolecular hydrogen bond of ligand leads to the entropic gain of 1:2 complex.•The longer the ligand alkyl chain, the higher the formation constant.