Tuning the Spin Ground State in Heterononanuclear Nickel(II)−Copper(II) Cylinders with a Triangular Metallacyclophane Core

Two new heterometallic NiIInCuII(9−n) complexes [n = 1 (2) and 2 (3)] have been synthesized following a multicomponent self-assembly process from a n:(3 − n):2:6 stoichiometric mixture of Ni2+, Cu2+, L6−, and [CuL′]2+, where L and L′ are the bridging and blocking ligands 1,3,5-benzenetris(oxamate) and N,N,N′,N′′,N′′-pentamethyldiethylenetriamine, respectively. Complexes 2 and 3 possess a unique cyclindrical architecture formed by three oxamato-bridged trinuclear linear units connected through two 1,3,5-substituted benzenetris(amidate) bridges, giving a triangular metallacyclophane core. They behave as a ferromagnetically coupled trimer of two (2)/one (3) S = 1/2 CuII3 plus one (2)/two (3) S = 0 NiIICuII2 linear units with overall S = 1 NiIICuII8 (2) and S = 1/2 NiII2CuII7 (3) ground states.