Zinc and cadmium complexes of an 18-membered N4O2 oxaaza-Schiff base macrocycle and the corresponding reduced form

The metal templated (Cd and Zn) cyclocondensation of 2,6-pyridinedicarbalde hyde and 1,5-bis(2-aminophenoxy)-3-azapentane is reported together with the crystal structures of two mononuclear cadmium macrocyclic Schiff base comp lexes, [CdL1(NO3)(2)] 1 and [CdL1(H2O)(2)][ClO4](2) 2 and a dinuclear, mu-h ydroxy-bridged zinc macrocyclic Schiff base complex [Zn2L21(OH)][ClO4](3). CH3CN 3 . CH3CN. The corresponding reduced macrocycle, L-2, has been synthe sised by using the Mn-II-templated cyclocondensation of 2,6-pyridinedicarba ldehyde and 1,5-bis(2-aminophenoxy)-3-azapentane in methanol followed by an in situ reductive demetallation of the Schiff base macrocyclic manganese(I I) complex using excess sodium borohydride. The crystal structures of the f ree macrocycle L-2, [CdL2(NO3)(2)] 4 and [CdL2(CH3CN)(2)][ClO4](2) 5 are re ported.