title: Structure, magnetic properties and nuclease activity of pyridine-2-carbaldehyde thiosemicarbazonecopper(II) complexes.
abstract: New complexes of formulae [Cu(HL(2))(H(2)O)(NO(3))](NO(3)) (1), [{Cu(L(1))(tfa)}(2)] (2), [{Cu(L(1))}(2)(pz)](ClO(4))(2) (3) and {[{Cu(L(1))}(2)(dca)](ClO(4))}(n) (4), where HL(1)=pyridine-2-carbaldehyde thiosemicarbazone, HL(2)=pyridine-2-carbaldehyde 4N-methylthiosemicarbazone, Htfa=trifluoroacetic acid (CF(3)COOH), pz=pyrazine (C(4)H(4)N(2)) and dca=dicyanamide [N(CN)(2)](-), have been synthesized and characterized. The crystal structures of these compounds are built up of monomers (1), dinuclear entities with the metal centers bridged through the non-thiosemicarbazone coligand (2 and 3) and 1D chains of dimers (4). In all the cases, square-pyramidal copper(II) ions are present, except for the square-planar ones in 3. Magnetic measurements show antiferromagnetic couplings in 2, 3 and 4. The susceptibility data were fitted by the Bleaney-Bowers' equation for copper(II) dimers derived from H=-2JS(1)S(2) being the obtained J/k values -4.8, -4.3 and -5.1K for compounds 2-4, respectively. The magnetic susceptibility of the already known [{Cu(HL(1))(tfa)}(2)](tfa)(2) compound has been also measured for the first time. The J/k value is -0.3K, lower than that in 2. The nuclease activity of 3 and 4 has been analyzed.
authors.affiliation: Departamento de Química, Universidad de Burgos, Misael Bañuelos s/n, 09001 Burgos, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Gómez-Saiz
authors.forename: Rubén
authors.initials: R
authors.lastname: Gil-García
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Maestro
authors.forename: José Luis
authors.initials: JL
authors.lastname: Pizarro
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Arriortua
authors.forename: Luis
authors.initials: L
authors.lastname: Lezama
authors.forename: Teófilo
authors.initials: T
authors.lastname: Rojo
authors.forename: Marta
authors.initials: M
authors.lastname: González-Alvarez
authors.forename: Joaquín
authors.initials: J
authors.lastname: Borrás
authors.forename: Javier
authors.initials: J
authors.lastname: García-Tojal
mesh_terms: D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D008280:Magnetics; D009942:Organometallic Compounds / Q000737:chemistry / Q000378:metabolism*; D011725:Pyridines / Q000737:chemistry* / Q000378:metabolism; D013882:Thiosemicarbazones / Q000737:chemistry* / Q000378:metabolism
chemical_list: D009942:Organometallic Compounds; D011725:Pyridines; D013882:Thiosemicarbazones; C432864:pyridine-2-carbaldehyde; D003300:Copper; D004247:DNA