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RESEARCH PRODUCT

Structure, magnetic properties and nuclease activity of pyridine-2-carbaldehyde thiosemicarbazonecopper(II) complexes.

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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 4 N -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  = –2 JS 1 S 2 being the obtained J/k values −4.8, −4.3 and −5.1 K 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 –0.3 K, lower than that in 2 . The nuclease activity of 3 and 4 has been analyzed.