The synthesis of [HB]3,5-(Butph)2pz]3]− (Butph = p-C6H4But), a new tris(pyrazolyl)hydroborato ligand: the crystal and molecular structure of Tl{η3-HB[3,5-(Butph)2pz]3}

The synthesis of a new sterically demanding tris(pyrazolyl)hydroborato ligand, [HB[3,5-(Butph)2pz]3]− (Butph = para-C6H4But), is reported. The potassium derivative is prepared by the direct reaction of KBH4 with 3,5-bis(para-tert-butylphenyl)pyrazole. Metathesis with TlNO3 converts the potassium derivative to the thallium complex Tl{η3-HB[3,5-(Butph)2pz]3}. The crystal and molecular structures of the pyrazole derivative [3,5-(Butph)2pz]2ZnI2 and the thallium derivative Tl{η3-HB[3,5-(Butph)2pz]3} have been determined.