NICKEL(II) COMPLEXES OF TETRAAZA MACROCYCLIC LIGANDS BEARING PENDANT DONOR GROUPS .2. STRUCTURAL CRYSTALLOGRAPHIC STUDIES OF NOVEL CONFORMATIONS OF NI[14]N-4-4,11-DIENE

Crystal and molecular structures of octahedral 2,9-trans-(4b) and 4,8, 11-tetraazacyclotelradeca-4,11-dienenickel(II) (4d) complexes as well as of the protonated square-planar form of the latter (3d) are describ ed. The conformations of chelate rings, as the fragments of macrocycli c cations, are defined from their calculated puckering parameters. The novel conformations of coordinated [14]N-4-4,11,-diene: a planar one with two inverted N-C-C-N segments of the macrocycle in cation 3d and a folded one with all four N-C-C-N and N=C-C-C-N inverted segments of the macrocycle in 4d are identified and compared with model macrocycle s to indicate the structural differences. A new notation of structures of macrocyclic cations is proposed.