5-COORDINATE BETA-KETOIMINATE DERIVATIVES OF THE (N-3-MACROCYCLE)NICKEL(II) FRAGMENT CYCLE=2,4,4-TRIMETHYL-1,5,9-TRIAZACYCLODODEC-1-ENE ANDITS 9-METHYL DERIVATIVE)

The hydroxo complexes [{Ni(N-3-macrocycle)(mu-OH)}(2)](ClO4)(2) (N-3-m acrocycle = 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene (N-3-mc) and 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene (9-Me-N-3-mc)) react with the appropriate beta-ketoimine to give five-coordinate nickel(II) complexes of the type [Ni(N-3-macrocycle) (C6H5COCHC(NR)CH3)](ClO4). The complexes have been studied by spectroscopic (IR, UV-vis, H-1 NMR and NOE) and thermal methods. An X-ray diffraction study carried out w ith the complex [Ni(9-Me-N-3-mc) {C6H5COCHC(NC6H5)CH3}](ClO4) has esta blished that the Ni atom presents a square pyramidal coordination and is displaced 0.325(1) Angstrom out of the basal plane towards the apic al N1 atom. (C) 1997 Elsevier Science Ltd.