REV. CHIM. (Bucureºti) ♦ 59 ♦ Nr.5 ♦ 2008 505 Coordination Compounds of Several Transition Metals with Phenyl-2-pyridyl-ketone ANGELA KRIZA 1 *, MARIANA TATUCU 2 , NICOLAE STANICA 3 , PAUL GABRIEL ANOAICA 2 1 University of Bucharest, Faculty of Chemistry, 23 Dumbrava Roºie Str., 70254, Bucharest, Romania 2 University of Medicine and Farmacy of Craiova, Faculty of Farmacy, 66 1 Mai Str., 200638, Craiova, Romania 3 Romanian Academy, Physical-Chemistry Institute,202 Spl. Independenþei, 77208, Bucharest, Romania Cobalt (II), nickel (II), copper (II), cadmium (II), and mercury(II) complexes with phenyl-2-pyridyl-ketone as ligand were synthesized at room temperature in ethanolic solution. The donor atoms and the possible geometry of the complexes were determined by means of elemental analysis, molar conductivities, IR, electronic, and EPR spectroscopies, magnetic measurements, and thermogravimmetric analysis. Keywords: Co(II), Ni(II), Cu(II), Cd(II), Hg(II) complexes, phenyl-2-pyridyl-ketone Recently, the research in the field of coordination chemistry has been focused on the preparation of complex combinations containing ketone ligands with aromatic rings or heterocyclic structure. This type of complexes can be further used for the synthesis of polymers with interesting magnetic properties. Some of these ligands show specific characteristics, like the formation of clusters [1,2]. Complex combinations containing di-2-pyridyl- ketone (dpk) as a ligand have already been prepared, structurally characterized and their magnetic properties determined. They showed either dimmer structure with thiocyanate bridges or an extended polymer structure [3]. Also, the compounds showed antiferromagnetic properties. Our research interest has been lately focused on the synthesis and characterization of coordination compounds of transition metal ions with ketone ligands [4]. The present work describes the synthesis and characterization of seven new combinations formed by several transition metals with the phenyl-2-pyridyl-ketone (ppk) (fig. 1). * Tel.: 0727845515 Synthesis Seven new complexes of the phenyl-2-pyridyl-ketone ligand with Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) were obtained through synthesis at room temperature and under no agitation. Their molecular formula depends on the nature of the metal ion and the nature of the anion present in the solution. The synthetic procedure was similar for all seven metallic complexes: the etanolic solutions of the metallic salts (or aqueous solution in the case of CdCl 2 . 5/2H 2 O and Cu(CH 3 COO) 2 . H 2 O) dissolved as 1 mmol salt in 15 mL ethanol, were added to the ethanolic solution of the phenyl-2-pyridyl-ketone dissolved as 2mmol in 15mL ethanol. Crystals of various colors were formed after the slow evaporation of the solvent (amorphous precipitates resulted in the case of metal complexes synthetized from CuCl 2 . 2H 2 O and Cu(CH 3 COO) 2 . H 2 O). The resulted crystals were filtrated, washed with ethanol, and dried within a desiccator for 24 h. Methods The metal complexes were characterized by elemental analysis, measurements of conductance and magnetization, IR, UV-Vis and EPR spectroscopy and thermogravimmetric analysis. The metal content was determined by gravimmetry (Co, Cd as pyrophosphates, Ni using dimethylglyoxime, Cu using salicylaldoxime), Hg was determined volumetrically in the presence of erio T, the chloride ion was determined gravimmetrically as AgCl, while carbon, hydrogen, nitrogen and sulphur were determined by combustion, using an Carlo-Erba 1104 apparatus. The melting points were determined by using a Stuart Scientific apparatus. The conductometric measurements were performed at room temperature, with Consort C-533 conductometer using methanolic solutions (10 -3 M). The magnetic measurements were performed also at room temperature, using the Faraday method. The IR spectra (4000 - 400 cm -1 ) were recorded in KBr pellets on a Bio- Rad FTS 135 spectrometer, while the UV-Vis spectra were recorded on a VSU-2P (Carl-Zeiss Jena) in reflection- diffusion mode, using MgO as a standard. The EPR spectrum of [Cu 2 (L) 2 (Ac) 4 ] . H 2 O was recorded on an ART-5 IFIN Bucharest apparatus, at the X frequency band of 9060 MHz, under a modulated magnetic field of high frequency (100 kHz). The measurements were Fig. 1. Phenyl-2-pyridyl-ketone (ppk) Compared to di-2-pyridyl-ketone, which suffers the solvolysis reaction in the presence of metal ions, in methanolic solution, in the same conditions, the phenyl-2- pyridyl-ketone conserves its ketone structure acting as a bidentate (or monodentate) ligand. Experimental section Chemicals Cobalt chloride hexahydrate (CoCl 2 . 6H 2 O, 99.99%), nickel chloride hexahydrate (NiCl 2 . 6H 2 O, 99.99%), copper chloride dihydrate (CuCl 2 . 2H 2 O, 99.99%), copper sulfate pentahydrate (CuSO 4 . 5 H 2 O, 99.99%), copper acetate monohydrate (Cu(CH 3 COO) 2 . H 2 O, 99.99%), cadmium chloride dihydrate (CdCl 2 . 21/2H 2 O, 99.99%), mercury chloride (HgCl 2 ) and phenyl-2-pyridyl-ketone (98%) were purchased from Merck and used as received.