Synthesis, Characterization, and Properties of Some Copper( II ) Complexes of 2‐Pyridineformamide Thiosemicarbazone (HAm4DH)

Reactions between different copper( II ) salts and 2‐pyridineformamide thiosemicarbazone (HAm4DH) in neutral ethanolic media led to the formation of complexes with the formulae [Cu(HAm4DH)X 2 ] (X = Cl or Br) ( 1 , 2 ) and [Cu(HAm4DH) 2 ]X 2 (X = NO 3 or ClO 4 ) ( 3 , 4 ). The same reactions carried out in the presence of triethylamine gave rise to new complexes with the general formulae [Cu(Am4DH)X] (X = Cl, Br, AcO, or NO 3 ) ( 5 – 8 ), [Cu(H 2 O)(Am4DH)](ClO 4 ) ( 9 ), and [Cu(Am4DH) 2 ] ( 10 ), many of which were isolated with different molecules of crystallization and contain a deprotonated thiosemicarbazone (Am4DH). These complexes were characterized by elemental analysis, and different spectroscopic and magnetic techniques. The thermal and redox behavior of the complexes was also evaluated. Complexes 1 , 2 , 5 , and 6 show better nuclease activity than [Cu(phen) 2 ] 2+ . Inaddition, crystals were isolated in the cases of [Cu(HAm4DH)Cl 2 ] 2 ( 5a ), 1 ∞ [Cu(Am4DH)Cl] ( 5b ), 1 ∞ [Cu(Am4DH)Br] ( 6a ), and [Cu(HAm4DH)(H 2 O)(ClO 4 ) 2 ] · MeOH · H 2 O ( 9a ) and these structures were analyzed by X‐ray diffraction. Compound 5a has a dimeric structure with chlorine bridges and shows weak antiferromagnetism ( J = –12.2 cm –1 ). Complexes 5b and 6a are one‐dimensional polymers formed through halogen bridges and the deprotonated thiosemicarbazone in the thiolate form. In compound 9a the copper( II ) is in a distorted octahedral environment with two ClO 4 units coordinated to the metal center. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)