Crystal structure of cis bis(4-benzoyl-3-methyl-1-phenyl pyrazol-5-one)- cis bis(methanol)-cobalt(II), C36H34CoN4O6

Abstract

C 36 H 34 CoN 4 O 6 ,monoclinic, P2 1 /n (no. 14), a =13.9021(5) Å, b =13.9557(5) Å, c =17.3379(6) Å, b =101.254(2)°, V =3299.1 Å 3 , Z =4,R gt (F) =0.0316, wR ref (F 2 ) =0.0869, T =200 K. Source of materialTo as olution of Bmpp-Ph (3-methyl-1-phenyl-4-[(phenyl)(2-phenylhydrazin-1-yl)methylidene]-1H-pyrazol-5(4H)-one, 2 mmol, 0.74 g) in hot ethanol (40 mL) was addedindrops aqueous solution of CoCl 2 ×4H 2 O(1mmol, 0.20 g) while stirring under reflux. After 4hofreflux, the pink precipitate was filtered, washed with ethanol/water (1:1), dried at room temperature and stored over fused CaCl 2 .Slow evaporation of asolution of the resultant pink solid in methanol afforded orange crystals of an unprecedented Co(Bmpp) 2 (MeOH) 2 suitable forx-raycrystallography. Experimental detailsCarbon-boundHatoms were placed in calculated positionsand were included in therefinement in the riding model approximation, with U iso (H) set to 1.2 U eq (C). The Hatoms of the methyl groups were allowed to rotate with afixed angle around the C-C bond to best fit the experimental electron density (HFIX 137 in the SHELX program suite [11]), with U iso (H) set to 1.5 U eq (C). The oxygen-bound Hatomswere located on adifference Fourier mapand refined freely. DiscussionAs an analytical reagent acylpyrazolones have been employed as good spectroscopicchelating ligand forthe determinationofmetalsintrace amounts[1],they have also been used as excellent catalysts [2]. They arebioactive di-ketone heterocycles [3]and are capable of formingSchiffbases with aminogroups [4,5].Successful coordination of acylpyrazolone diketones with transition metals have been reported to increase their catalyticp roperties [6]. We have already reported abioactive cobalt complex of acylpyrazolone [7]. In view of our interest in metal complexes of Schiff bases, presentedhereinisthe molecularand crystal structure of anew cobalt complex. The studies on the bioactive and catalytic activities of the title compound are presently ongoing. In thecrystal structurethe title complex has an octahedral coordination geometry consisting of two Bmpp ligands and two coordinating methanol molecules. Each 4-benzoyl-3-methyl-1-phenyl pyrazol-5-one (Bmpp)l igand is deprotonated with the negative charge delocalized. The Bmpp ligands occur cis to each other similarly to the cis complex reported by Wu et al. [8]which has one methanol and one ethanol ligand. In contrast the complex we reported earlier [7]with two coordinating ethanol ligands has two Bmpp ligands trans to each other. Theaverage Bmpp Co-O bond length here is 2.070(33) Åwhich is very similar to the mixed ethanol methanol complex [8] wheret he average bond length is 2.071(29) Å. In the complex with the two trans ethanols [7] the average Co-O bond length is only slightly shorter at 2.038(36) Å. The title complex is obviously non-centrosym-metrical therefore the two Bmpp ligands having different geometrical configurations. In the first ligand the dihedral angle between the least square planes through the phenyl rings is 20.76(...