Flux Synthesis of New Bis(Salicylato)borates

Chemistry, HKUST
â—‹Alex S-F Au-Yeung Mingmei Wu Gavin K-C Wan Herman H-Y Sung Ian D Williams

Molten boric acid 'flux' synthesis has been used for the preparation of borate-rich clusters [1] and porous frameworks[2]. We recently found the use of boric acid flux conditions can lead to new bis(salicylato)borate compounds by this HT method, through direct reaction of boric and salicylic acids and either inorganic or organic bases. For example use of Li(OH) results in Li[(BSal2)(H2O)]n a new material with a double-chain structure and with potential applicability for Li batteries. Organic molecular salts can also be prepared such as [pipz-H2][BSal2]2 (see fig) by reaction of piperazine, salicylic and boric acid. The importance of the flux condition is emphasized since use of hydrothermal conditions through water addition leads to reduced yields and in the organic case the simple salt [pipz-H2][Sal-H]2 is formed with no boron incorporation. [Sal = (C7H4O3)2-]

1. I. D. Williams, M. Wu, H. H-Y. Sung, X. X. Zhang and J. Yu, Chem. Commun., 1998, 2463.
2. J. L. Rowsell, N. J. Taylor, L. F. Nazar, J. Amer. Chem. Soc., 2002, 124, 6522
The RGC is thanked for financial support of this work (grant 6043-05)