INFLUENCE OF LACTAM RING SIZE ON METALLAMACROCYCLE RING TYPE - SYNTHESIS AND CRYSTAL-STRUCTURE OF THE HETEROMETALLIC COMPLEX [HG2ER(C8H14NO)4(NO3)3]N

Reaction of 2-azacyclononanone (= LH) with mercury(II) acetate and erbium (III) nitrate in methanol yields the compound [Hg2ErL4(NO3)3]n (1), which has been characterized by X-ray diffraction. Each erbium atom is eight-coordinate and has two bidentate nitrates and two chelating HgL2 units bonded to it. The remaining nitrate ion serves to link molecules of 1 to produce polymeric chains. The formation of the eight-membered mercury/erbium-containing rings results in a structure which is radically different from those previously found for the mercury/lanthanide complexes formed by the smaller ring lactams, 2-azacyclobutanone and 2-azacyclopentanone.