Efficient mechanochemical synthesis of tris(pyrazolylborate) complexes of manganese(II), cobalt(II) and nickel(II)

A mechanochemical synthesis of Mn(II), Co(II) and Ni(II) tris(pyrazolylborates) (Tp−) was developed, which enabled preparation of metal complexes of the type TpMCl and TpMCl · Hpz type (Hpz is the substituted pyrazole generated by hydrolysis of the corresponding Tp− ligand). The X-ray structure of a new Co(II) tris(pyrazolylborate) and the electronic spectra of these coordination compounds are discussed.