title: Trinuclear, tetranuclear, and polymeric Cu(II) complexes from the first use of 2-pyridylcyanoxime in transition metal chemistry: synthetic, structural, and magnetic studies.
abstract: The first use of 2-pyridylcyanoxime, (py)C(CN)NOH, in transition metal chemistry is described. Depending on the nature of the metal starting material and the reaction conditions employed, the Cu(II)/(py)C(CN)NOH system has provided access to complexes [Cu(3)O{(py)C(CN)NO}(3)(NO(3))(H(2)O)(2)(MeOH)] (1), [Cu(4)O{(py)C(CN)NO}(4)(O(2)CMe)(2)] (2), [Cu(4)(OH)(2){(py)C(CN)NO}(2)(O(2)CPh)(4)](2n)·n[Cu(4)(OH)(2){(py)C(CN)NO}(2)(O(2)CPh)(4)] (3), and [Cu{(py)C(CN)NO}(2)](n) (4). The molecule of 1 consists of three Cu(II) atoms in a strictly equilateral arrangement bridged by a central μ(3)-oxide group. The molecule of 2 consists of a tetrahedron of Cu(II) atoms held together by a central μ(4)-oxide ion, four η(1):η(1):η(1):μ-(py)C(CN)NO(-) ligands and two η(1):η(1):μ-MeCO(2)(-) groups. The crystal structure of 3 consists of [Cu(4)(OH)(2){(py)C(CN)NO}(2)(O(2)CPh)(4)](2n) double chains and discrete cluster [Cu(4)(OH)(2){(py)C(CN)NO}(2)(O(2)CPh)(4)] molecules. The crystal structure of 4 consists of neutral polymeric chains based on centrosymmetric mononuclear [Cu{(py)C(CN)NO}(2)] units. The Cu(II) atoms are doubly bridged by the oximate groups of two η(1):η(1):η(1):μ-(py)C(CN)NO(-) ligands. Variable-temperature, solid-state direct current (dc) magnetic susceptibility studies were carried out for 1-4. The data indicate very strong antiferromagnetic exchange interactions for 1-3. The obtained J values are discussed in depth on the basis of the structural parameters of the complexes, literature reports, and existing magnetostructural correlations.
authors.affiliation: Departament de Química Inorgànica and Institut de Nanociència i Nanotecnologia, Universitat de Barcelona (IN2UB), Martí I Franqués 1-11, 08028-Barcelona, Spain. albert.escuer@ub.edu
authors.forename: Albert
authors.initials: A
authors.lastname: Escuer
authors.forename: Gina
authors.initials: G
authors.lastname: Vlahopoulou
authors.forename: Spyros P
authors.initials: SP
authors.lastname: Perlepes
authors.forename: Franz A
authors.initials: FA
authors.lastname: Mautner
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008280:Magnetics; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010091:Oximes / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*
chemical_list: C558939:2-pyridylcyanoxime; D009942:Organometallic Compounds; D010091:Oximes; D011108:Polymers; D011725:Pyridines; D003300:Copper