Boric acid complexes with organic biomolecules: Mono-chelate complexes with salicylic and glucuronic acids

Two mono-chelate borate complexes, lithium mono-salicylatoborate and sodium mono-glucuronatoborate, are reported for the first time. The complexes were isolated from aqueous solutions and characterized by FTIR (Fourier Transform Infrared) and 13C MAS (Magic Angle Spinning) NMR techniques. Thermal stabilities of the complexes were examined by recording their TGA (Thermogravimetric Analysis) curves. Lithium mono-salicylatoborate, Li[B(Sal)(OH)2], was isolated in crystal form and presented as a novel hybrid metal–organic framework possessing zeolitic structure. X-ray analysis revealed an original crystal structure constructed with solvate-free lithium ions adopting two different types of coordination polyhedra, corner-sharing LiO4 (tetrahedral) and LiO5 (distorted square pyramidal), in the same framework.

Graphical abstractTwo mono-chelate borate complexes are reported. Lithium mono-salicylatoborate, Li[B(Sal)(OH)2], is presented as a novel, hybrid metal–organic framework possessing zeolitic structure constructed with corner-sharing tetrahedral LiO4 and square pyramidal LiO5 polyhedra. Characterization of sodium glucuronatoborate, Na[B(Glu)(OH)2]·2H2O, by 13C MAS NMR is also reported.Figure optionsDownload full-size imageDownload as PowerPoint slide