Influence of geometric and electronic features of pyridine derivatives and triethylamine on the formation of a metal carboxylate core in reactions producing cadmium(ii) pivalate complexes

Abstract

The reaction products of [Cd(piv)2] (piv is–O2CBut) with isoquinoline (iqn), 2,4-lutidine (lut), phenanthridine (phend), 2,3-cyclododecenopyridine (cpy), and triethylamine (Et3N) were synthesized and their structures were determined. The steric factors were found to play a more important role in cadmium(ii) pivalate complexes compared to 3d metal carboxylates in the +2 oxidation state. The reaction of [Cd(piv)2] with isoquinoline produces only the mononuclear complex [Cd(piv)2(iqn)3] (1). The reaction of [Cd(piv)2] with pyridine derivatives bearing a bulky substituent at the α position is accompanied by the formation of symmetrical dinuclear complexes of the composition [Cd2(piv)4(L)2]. In the complexes with L = lut (2) or phend (3), the cadmium(ii) atoms are linked by two chelating-bridging carboxylate groups; in the complex with L = cpy (4), by four bidentate-bridging groups. The reaction of [Cd(piv)2] with Et3N in a solution of MeCN gives the centrosymmetric linear trinuclear complex [Cd3(piv)6(Et3N)2] (6); in a mixture of benzene and hexane, the ionic compound (HEt3N)[Cd2(piv)5(H2O)] (7). The crystal structures of all synthesized compounds were determined by X-ray diffraction.