Nickel(II) complexes containing tetradentate ligands formed by the condensation of ketones with benzil monohydrazone in the presence of nickel(II) ions

Synthesis and characterization of mono- and heterodinuclear complexes with dicompartmental macrocyclic ligand containing hexa- and pentadentate coordination sites

“…Formation of the five-membered ring in the diethylenetriamine link is as a result of the nucleophilic attack of aminic nitrogen N(5) on the C(34)@N(7) double bond, which is facilitated by presence of a Lewis acid such as Ni(II). This type of reaction closely parallels to that reported by Kerwin and Melson [24] The Zn-Ni intermetallic separation bridged by two phenolic oxygen atoms is 3.104 Å . The Ni-O and Ni-N bond distances are from 1.833(4) Å to 1.916(4) Å .…”

Template condensations: metal-ion-directed syntheses of macrocyclic complexes from 2,3-butanedione dihydrazone and aldehydes or ketones

“…This approach is a natural extension of earlier work on metal carbonyl fragments10 and MCp2 fragments. 11 We begin with a development of the valence orbitals of Fe2(CO)6, Fe being chosen as a typical transition metal, followed by a brief look at other related fragments, and then a discussion of bonding patterns with various ligands.…”

Structure de (diméthyl-5,5 diphényl-1,9 tétraaza-3,4,6,7 nonatétraène-1,3,6,8 diolato-1,9-O,O',N,N')nickel(II), [Ni(C19H18N4O2)]

“…La r6action template entre des monohydrazones et des c&ones en presence d'ions Ni 2+ conduit ~. la formation de complexes polydent6s polyaza (Kerwin & Melson, 1972). Les auteurs ont tent6 d'61ucider les m6canismes r6actionnels qui conduisent ~ la formation d'un tel ligand polydentate dans la sph6re de coordination du nickel(II) (Bonfoey & Melson, 1975).…”