Synthesis, characterization, and reactivity of a novel thallium arylspiroboronate ester

Abstract

Addition of 3,5-di-tert-butylcatechol (butcat) to solutions of H3B·SMe2 gave the novel diboron species B2(butcat)3 (2) in moderate to high yields. Compound 2 reacts with Tl(acac) to give butcatB(acac) (4) and Tl(Bbutcat2) (5). Attempts to abstract the chlorides from [(dppb)Rh(µ-Cl)]2 (where dppb = 1,4-bis(diphenylphosphino)buthane) using 5 led to the unusual dimer [(dppb)Rh(µ-Cl)2(µ-Tl)Rh(dppb)][Bbutcat2] (6), which contains an unsymmetrical Rh–Tl–Rh bridge.Key words: arylspiroboronate ester, non-coordinating anion, rhodium, thallium.