Acid form of Trofimenko’s scorpionates, H(Tp^R,R′); comments on synthesis and solid-state structure of H(Tp^tBu,Me)

Abstract

We report a re-examination of Trofimenko’s original protocol for the preparation of the acid form of his hydrotris(pyrazolyl)borates, H(Tp^R,R′), by the treatment of M(Tp^R,R′)with glacial acetic acid. It is concluded that the protocol is effective as long as the 3-substituent of the pyrazolyl moiety is sufficiently bulky to provide steric protection to the acidic N–H proton. The solid-state structure of H(Tp^tBu,Me), the acid form of the popular Tp^tBu,Me ligand is also presented.