EPR spectroscopic study of a dinuclear copper(II) complex of tolfenamic acid

Synthesis, crystal structures and characterizations of three new copper(II) complexes including anti-inflammatory diclofenac

Three new diclofenac-based copper(II) complexes, namely tetrakis{μ-2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O:O′}bis(methanol-κO)copper(II), [Cu2(μ-dicl)4(CH3OH)2] (1), bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O,O′}bis(1-vinyl-1H-imidazole-κN 3)copper(II), [Cu(dicl)2(vim)2] (2), and bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O,O′}bis(1H-imidazole-κN 3)copper(II), [Cu(dicl)2(im)2] (3) [dicl is diclofenac (C14H10Cl2NO2), vim is 1-vinylimidazole (C5H6N2) and im is imidazole (C3H4N2)], have been synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. X-ray diffraction analysis shows that complex 1 consists of dimeric units in which the dicl ligand exhibits a bidentate syn,syn-μ2 coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)2 L 2] (L is vim or im) in which the CuII ions are octahedrally coordinated by two L and two dicl chelating ligands. The L and dicl ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of dicl in the title complexes were revealed by Fourier transform IR (FT–IR) spectroscopy. The spin matching between the copper(II) centres in the dimeric [Cu2(μ-dicl)4(CH3OH)2] units was also confirmed by magnetic data to be lower than the spin-only value and electron paramagnetic resonance (EPR) spectra. The thermal properties of the complexes were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) techniques.

Synthesis, crystal structure and EPR spectroscopic analysis of novel copper complexes formed from N-pyridyl-4-nitro-1,8-naphthalimide ligands

The synthesis of two new monodentate pyridyl based 4-nitro-1,8-naphthalimide ligands and their corresponding Cu-complexes (using various salts) is described. Of these, complexes 1–3 and 5, all gave rise to structures that were characterised by X-ray crystallography and EPR.

Synthesis, Spectroscopy, and Magnetic Characterization of Copper(II) and Cobalt(II) Complexes with 2-Amino-5-bromopyridine as Ligand

The synthesis, spectroscopic, and magnetic characterization of two new copper(II) and cobalt(II) complexes are described. Both two compounds have the general formula [M(L)2(Cl)2], in which L= 2-amino-5-bromopyridine. These complexes were prepared in one-step synthesis and characterized by elemental analysis, FTIR, UV-Vis, and EPR spectroscopy. Moreover, the single crystal structure of complex (1) was studied by the X-ray diffraction method. This compound consists of mononuclear units consisting of two ligands linked to metal via the nitrogen of pyridine ring. The UV-Vis spectra of copper(II) and cobalt(II) complexes show three and five absorption bands, respectively, attributed to the d-d transition of the metal ion, ligand → metal charge transfer, and π→π∗ or n→π∗ transitions of the ligand. The FTIR spectra show MN2Cl2 vibrations at 500–300 cm−1. The complexes show room temperature magnetic moments of 1.78 BM and 4.12 BM for Cu(II) and Co(II), respectively. The X-band electron spin resonance (ESR) spectra of Cu(II) complex in DMF or DMSO frozen at liquid nitrogen temperature show the typical ΔMS=±1 transition.

Unusual coordinating behavior by three non-steroidal anti-inflammatory drugs from the oxicam family towards copper(II). Synthesis, X-ray structure for copper(II)-isoxicam, -meloxicam and -cinnoxicam-derivative complexes, and cytotoxic activity for a copper(II)-piroxicam complex

Cytotoxic tests recently performed at National Cancer Institute, NCI (USA), on [Cu(HPIR)(2)(DMF)(2)], 1, (H(2)PIR=piroxicam, 4-hydroxy-2-methyl-N-pyridin-2-yl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) a widely used non-steroidal anti-inflammatory drug, NSAID [see R. Cini, G. Giorgi, A. Cinquantini, C. Rossi, M. Sabat, Inorg. Chem. 29 (1990) 5197-5200, for synthesis and structural characterization, DMF=dimethylformamide] (NSC #624662) by using a panel of ca. 50 human cancer cells, showed growth inhibition factor GI(50) values as low as 20microM against several cancer lines, with an average value 54.4microM. The activity of 1 is larger against ovarian cancer cells, non-small lung cancer cells, melanoma cancer cells, and central nervous system cancer cells. The widely used anticancer drug carboplatin (cis-diammine(1,1-cyclobutanedicarboxylato)platinum(II)) (NSC #241240) has average GI(50) value of 102microM. The reactions of copper(II)-acetate with other NSAIDs from the oxicam family were tested and crystalline complexes were obtained and characterized. Isoxicam (H(2)ISO=4-hydroxy-2-methyl-N-(5-methylisoxazol-3-yl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) produced [Cu(HISO)(2)].0.5DMF, 2.0.5DMF (DMF=dimethylfomamide). The coordination arrangement is square-planar and the HISO(-) anions behave as ambi-dentate chelators via O(amide),N(isoxazole) and O(enolate),O(amide) donors. Meloxicam (H(2)MEL=4-hydroxy-2-methyl-N-(5-methyl-1,3-thiazol-2-yl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) produced [Cu(HMEL)(2)(DMF)].0.25H(2)O, 3.0.25H(2)O. The coordination arrangement is square-pyramidal, the equatorial donors being O(amide),N(thiazole) from two HMEL(-) anions and the apical donor being O(DMF). Unexpectedly, cinnoxicam (HCIN=2-methyl-1,1-dioxido-3-[(pyridin-2-ylamino)carbonyl]-2H-1,2-benzothiazin-4-yl-(3-phenylacrylate)) produced [Cu(MBT)(2)(PPA)(2)] (MBT=3-(methoxycarbonyl)-2-methyl-2H-1,2-benzothiazin-4-olate 1,1-dioxide, PPA=3-phenyl-N-pyridin-2-ylacrylamide).