Synthesis and characterization of new complexes derived from 4-thienyl substituted pyrimidines

The behavior of 4-thienyl substituted pyrimidine ligands (L1–3) has been studied for the series of their reactions with various salts of 3d metals (Co, Zn, Ni, Cu) and platinoids (Pt, Pd). In particular, mononuclear Co(OTf)2(L1–3)2(H2O)2(MeCN)2 (1), binuclear Co2(Piv)2(L1–3)4 (2a,b), Cu2(Piv)2(L1–3)2 (5a,b), heterometallic polynuclear Li2Co2(Piv)6(L1–3)2 (4) and chelate [(L1)Pd(OAc)]2 (6) complexes have been obtained. The structures of all complexes have been established by X-ray diffraction. Also magnetic properties of coordination compounds 1, 2, 4 and 5 have been studied in details. In particular, mononuclear Co(II) complexes 1 and 4 proved to exhibit paramagnetism with large positive zero-field splitting parameters. Dinuclear Co(II) complexes 2a,b show weak antiferromagnetic interactions. Dinuclear Cu(II) complexes 5a,b demonstrate strong antiferromagnetic superexchange interactions via four carboxylate bridges. The systems 2a,b and 5a,b are isolated as exchange coupled dimers.