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

The behavior of 4-thienyl substituted pyrimidine ligands (L 1–3 ) 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 (L 1–3 ) 2 (H 2 O) 2 (MeCN) 2 ( 1 ), binuclear Co 2 (Piv) 2 (L 1–3 ) 4 ( 2a , b ), Cu 2 (Piv) 2 (L 1–3 ) 2 ( 5a , b ), heterometallic polynuclear Li 2 Co 2 (Piv) 6 (L 1–3 ) 2 ( 4 ) and chelate [(L 1 )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. [ABSTRACT FROM AUTHOR]