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

Resumo

The reaction products of [Cd(piv)₂] (piv is–O₂CBu^t) 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.