Coordination chemistry of nitrile and amino pendant arm derivatives of [9]aneN₂S and [9]aneN_S2 with Pd^II and Cu^II

Palladium(II) and copper(II) complexes [Pd(L¹)Cl₂], [Pd(L³)-Cl₂], [Cu(L¹)Cl₂], [Cu(L³)Cl₂], [Pd(L²)][BF₄]₂, [Pd(L⁴)Cl]-BF₄, [Cu(L²)][NO₃]₂ and [Cu(L⁴)Cl]PF₆ of the nitrile (L¹ and L³) and amino (L² and L⁴) pendant arm derivatives of 1-thia-4,7-diazacyclononane ([9]aneN₂S) and 7-aza-1,4-dithiacyclononane ([9]aneNS₂) have been prepared and fully characterised. In each case, a square-pyramidal coordination sphere is observed at both metal ions with either one or two Cl^- anions completing the donor set. The tridentate nine-membered macrocyclic moiety adopts a [333] conformation in all the complexes obtained. The five-membered chelate rings involving the donor atoms of the basal plane adopt a gauche configuration with very similar degrees of puckering. The "innocent" nitrile pendant arms in L¹ and L³ do not bind to the metal ions, but still appear to influence the binding of the tridentate macrocyclic frameworks via the tertiary amine sites.