Solvent-free one-pot synthesis of thallium complexes of Tp [BH(Pz)3]− (Pz = pyrazolate) and its derivatives

Heating a 0.5:1:3 mixture of Tl2SO4, KBH4, and HPz or 3-, 4-, and/or 5-substituted derivatives without the use of any solvent afforded the corresponding thallium complexes of hydrotris(1-pyrazolyl)borate (Tp), and its various substituted forms in high yields. This simple and efficient method should enhance the utility of TlTp-related complexes, which are widely used as mild Tp ligand transfer reagents in the preparation of a variety of transition metal Tp complexes.