CRYSTAL-STRUCTURE AND ESR STUDY OF A BIMETALLIC COPPER IRON CROWN-ETHER INCLUSION COMPLEX

Bimetallic inclusion complexes have been synthesized by a secondary coordination interaction between the guest complex [Fe(eta-5-C5H5)(CO)2(NH3)][PF6] and copper(II) complex 1a or nickel(II) complex 1b containing crown-ether hosts. The X-ray crystal-structure analysis established that the Cu, Fe inclusion complex 2 crystallizes as a centrosymmetric dimer with a Cu-Cu separation of 3.73 angstrom and a novel out-of-plane Cu-N interaction. The magnetic parameters for 2 were obtained by ESR and ENDOR spectroscopy. ESR susceptibility measurements down to 6 K exclude the presence of any antiferromagnetic coupling interaction between the Cu(II) centers of the dimer.