Interaction of hydantoins with transition metal ions: synthesis, structural, spectroscopic, thermal and magnetic properties of [M(H2O)4(phenytoinate)2] M = Ni(II), Co(II)

Complexes of Ni(II) and Co(II) of the formulae [Ni(H2O)(4)(pht)(2)] (1) and [Co(H2O)(4)(pht)(2)]center dot 1,5NH(3)center dot H2O (2) (where pht = phenotoinate anion) were obtained and characterized physicochemically. [Ni(H2O)(4)(pht)(2)] (1) crystallizes in a monoclinic space group P2(1)/c; a = 11.7358(8), b = 11,1250(8), 11.4182(7) ; beta = 97.076(5)A degrees; V = 1479.41 (3); Z = 2. The environment around the nickel and cobalt ions can be described as a distorted octahedron. The metal ion was found to bind to four water molecules and two nitrogen atoms derived from two anions of the monodentate phenytoinate. Four intramolecular hydrogen bonds designated as S(6) graph set are found in one [Ni(H2O)(4)(pht)(2)] (1) molecule. Two chain HB patterns, constructed by the [Ni(H2O)(4)(pht)(2)] molecules extending along the c and b axes, respectively, have been observed. The cobalt complex precipitates with the additional solvent molecules: one and a half of ammonia and one water. The results document the preferential binding of hydantoins to the metal ions through N(3) atom.