title: Crystal structure and magnetic interactions in nickel(II) dibridged complexes formed by two azide groups or by both phenolate oxygen-azide, -thiocyanate, -carboxylate, or -cyanate groups.
abstract: Tridentate/tetradentate Schiff base ligands L(1) and L(2), derived from the condensation of o-vanillin or pyridine-2-aldehyde with N,N-dimethylethylenediammine, react with nickel acetate or perchlorate salt and azide, cyanate, or thiocyanate to give rise to a series of dinuclear complexes of formulas [Ni(L(1))(micro(1,1)-N(3))Ni(L(1))(N(3))(OH(2))].H(2)O (1), [[Ni(L(1))(micro(1,1)-NCS)Ni(L(1))(NCS)(OH(2))][Ni(L(1))(micro-CH(3)COO)Ni(L(1))( NCS) (OH(2))]] (2) [[2A][2B]], [Ni(L(1))(micro(1,1)-NCO)Ni(L(1))(NCO)(OH(2))].H(2)O (3), and [Ni(L(2)-OMe)(micro(1,1)-N(3))(N(3))](2) (4), where L(1) = Me(2)N(CH(2))(2)NCHC(6)H(3)(O(-))(OCH(3)) and L(2) = Me(2)N(CH(2))(2)NCHC(6)H(3)N. We have characterized these complexes by analytical, spectroscopic, and variable-temperature magnetic susceptibility measurements. The coordination geometry around all of the Ni(II) centers is a distorted octahedron with bridging azide, thiocyanate/acetate, or cyanate in a micro(1,1) mode and micro(2)-phenolate oxygen ion for 1-3, respectively, or with a double-bridging azide for 4. The magnetic properties of the complexes were studied by magnetic susceptibility (chi(M)) versus temperature measurements. The chi(M) nus T plot reveals that compounds 1 and 4 are strongly ferromagnetically coupled, 3 shows a weak ferromagnetic behavior, and 2 is very weakly antiferromagnetically coupled.
authors.affiliation: Department of Chemistry, Jadavpur University, Kolkata-700 032, India.
authors.forename: Subrata Kumar
authors.initials: SK
authors.lastname: Dey
authors.forename: Nijhuma
authors.initials: N
authors.lastname: Mondal
authors.forename: M Salah
authors.initials: MS
authors.lastname: El Fallah
authors.forename: Ramon
authors.initials: R
authors.lastname: Vicente
authors.forename: Albert
authors.initials: A
authors.lastname: Escuer
authors.forename: Xavier
authors.initials: X
authors.lastname: Solans
authors.forename: M
authors.initials: M
authors.lastname: Font-Bardía
authors.forename: T
authors.initials: T
authors.lastname: Matsushita
authors.forename: V
authors.initials: V
authors.lastname: Gramlich
authors.forename: Samiran
authors.initials: S
authors.lastname: Mitra