Job/Unit: Z12180 /KAP1 Date: 07-08-12 16:59:58 Pages: 8 ARTICLE DOI: 10.1002/zaac.201200180 Metal Derivatives of Thiosemicarbazones: Crystal and Molecular Structures of Mono- and Dinuclear Copper(II) Complexes with N 1 -Subsitituted Salicylaldehyde Thiosemicarbazones Tarlok S. Lobana,* [a] Poonam Kumari, [a] Ray J. Butcher, [b] Jerry P. Jasinski, [c] and James A. Golen [c] Keywords: Thiosemicarbazone; Copper; Bipyridine; Phenanthroline Abstract. Reactions of copper(II) acetate with N 1 -subsitituted salicyl- aldehyde thiosemicarbazones [R 1 R 2 C 2 =N 3 –N 2 H–C 1 (=S)–N 1 HR 3 ; R 1 = 2-HO–C 6 H 4 –, R 2 =H: R 3 = Me (H 2 L 1 ), Et (H 2 L 2 )] are described. Copper(II) acetate was reacted with H 2 L 1 and H 2 L 2 ligands in the pres- ence of polypyridyl co-ligands, and this led to the formation of mononuclear complexes, [Cu(κ 3 -O,N,S-L 1 )(κ 2 -N,N-bipy)] (1), [Cu(κ 3 -O,N,S-L)(κ 2 -N,N-phen)] [L = L 1 (3), L 2 (4)], [Cu(κ 3 -O,N,S- L)(κ 2 -N,N-tmphen)] [L =L 1 (5), L 2 (6)] and a dinuclear complex, [Cu 2 L 2 2 (bipy)] (2) (bipy = 2,2'-bipyridine, phen = 1,10-phenan- Introduction Thiosemicarbazones [R 1 R 2 C 2 =N 3 –N 2 H–C 1 (=S)–N 1 HR 3 ] represent an interesting class of N, S donor ligands due to their variable donor ability and structural diversity. [1–6] Salicylalde- hyde thiosemicarbazones with O, N, S donor atoms have been of considerable interest due to their remarkable structural and biological properties. [7–12] Interactions between aromatic rings of salicylaldehyde thio ligands are very important in proteins and protein-DNA systems for protein stabilization and various regulatory processes. [13–16] A number of thiosemicarbazones and their copper complexes have been found to be active in cell destruction, as well as in the inhibition of DNA synthe- sis. [17–19] The copper(II) metal ion is especially attractive for study because of its rich spectroscopic and magnetic properties that often change during the course of enzyme catalysis. There has been considerable interest in the compounds con- taining N,N donor co-ligands such as bipyridine and phenan- throline because of their versatile self-assembling properties and tendency to act as building blocks in the design of metal- ligand networks. [20,21] However, transition metal polypyridyl * Prof. Dr. T. S. Lobana E-Mail: tarlokslobana@yahoo.co.in [a] Department of Chemistry Guru Nanak Dev University Amritsar-143 005, India [b] Department of Chemistry Howard University Washington DC 20059, USA [c] Department of Chemistry Keene State College 229 Main Street Keene, NH 03435–2001, USA Z. Anorg. Allg. Chem. 0000, ,(), 0–0 © 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 throline, tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline). In dinu- clear complex 2, one ligand is O,N 3 ,S-chelating, while second is O,N 3 ,S-chelation-cum-N 2 -bridging; and in all others thio-ligands are O,N 3 ,S-chelating. The μ eff values for the complexes lie in the range of 1.79–1.83 BM. Complexes 1, 3–6 have square pyramidal arrangement, whereas complex 2 has two independent molecules in the crystal lat- tice, and each molecule has trigonal bipyramidal square planar (5:4) coordination pair. Complexes 2, 4, and 6 showed fluorescence proper- ties. base adducts containing thiosemicarbazones have not been much investigated. [1] For instance, for copper(II) there are lim- ited reports on complexes of salicylaldehyde based thiosemi- carbazonates (H 2 L) in the presence of polypyridyl N,N donors, namely, [Cu(κ 3 -O,N,S-L)(κ 2 -N,N-D)] (L = salicylaldehyde thiosemicarbazonate; D = bipy, phen), [Cu(κ 3 -O,N,S-L)(κ 2 - N,N-D)] (L = salicylaldehyde-N 1 -phenyl thiosemicarbazonate; D = bipy, phen), [Cu(κ 3 -O,N,S-L)(κ 2 -N,N-D)] (L = 3,5-di-tbu- 2-hydroxybenzaldehyde-N 1 -phenyl-thiosemicarbazonate; D = bipy, phen, dmp), and [Cu(κ 3 -O,N,S-L)(κ 2 -N,N-D)] (L = 2-hydroxy-acetophenone-N 1 -methylphenyl thiosemicarbazone; D = bipy) (bipy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline). [22] All these com- plexes have square pyramidal arrangement. Herein in this paper, copper(II) complexes with salicylalde- hyde-N 1 -methyl (or ethyl) thiosemicarbazones in the presence of N,N donor co-ligands (Scheme 1) are described and com- pared with its –N 1 HPh analogue. It was anticipated that the presence of electron releasing groups (R 3 = Me, Et) at N 1 atom in presence of polypyridyl co-ligands with π electron net works might alter chemical/optical properties such as bonding and fluorescence of the resulting complexes vis-à-vis those of the complexes having phenyl group at N 1 (–N 1 HPh) Scheme 1.