Spin Control in Ladderlike Hexanuclear Copper(II)Complexes with Metallacyclophane Cores

摘要

Two new hexanuclear oxamatocopper(II)complexes 3 and 4 have been synthesized from the binuclear copper(II)complexes of the meta- and para-phenylenebis(oxamate)ligands,respectively.Complexes 3 and 4 possess an overall ladderlike structure made up of two oxamate-bridged linear trinuclear units("rails")connected through two phenylenediamidate bridges("rungs")between the central copper atoms to give metallacyclic cores of the meta- and para-cyclophane type,respectively.They show different ground spin states,S=1(3)or S=0(4),depending on the substitution pattern in the aromatic spacers.The triplet state molecule 3 containing two spin doublet Cu~II _3 units connected by two m-phenylenediamidate bridges represents a successful extension of the concept of "ferromagnetic coupling units" to metal complexes,which is a well-known approach toward high spin organic radicals.