Supramolecular and metallosupramolecular coordination compounds of nickel(II) with the half units of vicinal oxime-imine ligands; mixed ligand complexes of the metal ion

The [1 + 1] condensation of isonitrosoacetylacetone (Hisoacac) with o-phenylenediamine produces the diazepine (HLBD) (1), which reacts with Ni(OAc)(2) . 4H(2)O (1:1 molar ratio) to produce the mixed ligand complex (LBDN)Ni(OAc) (2), where LBDN is the anion of the half unit obtained by hydrolysis of one HLBD imine linkage. The reaction of (2) (1 mol) with mono-, bi- and trichloroethanoic acid (1 mol) or picric acid (1 mol) led to the exchange of the acetate in (2) with the anion of the added acid [(3)-(6), respectively]. The supramolecular structure of (2)-(6) is achieved through the dimerization of these complexes via intermolecular hydrogen bonding of the LBDN -NH2 group of one molecule and the monodentate acetate group of another molecule. The template reaction of o-phen with Hisoacac in the presence of Ni(OAc)(2) . 4H(2)O (1:2:2 and 1:2:1 molar ratios, respectively) led to the formation of (LBDN)Ni(OAc)(2)Ni(isoacac) (7) and (isophen)Ni (8), respectively; H(2)isophen is a symmetrical Schiff base ligand formed by the (2:1) in situ condensation of Hisoacac with o-phen. The (1:1) condensation of Hisoacac with p-phen produced the half unit Hisopphen (9), whose 1:1 molar ratio reaction with Ni(OAc)(2) . 4H(2)O led to the formation of (isopphen)Ni(OAc) . 2H(2)O (10). The amino group of the isopphen ligand is available for further coordination with the nickel(II) ion to produce the metallosupramolecular complexes {[two molecules of complex (10)] [Ni(OAc)(2)]} and {[complex (10)] [Ni(OAc)(2) . H2O]} from the 2:1 and 1:1 molar ratio reactions, respectively, of (10) with Ni(OAc)(2) . 4H(2)O. The 1:1 molar ratio reaction of (10) with Hisoacac led to replacement of OAc by isoacac. The suggested structures of the ligands and their coordination compounds are based on analytical, chemical, spectral data and magnetic moments.