CRYSTAL STRUCTURES OF new ISOSTRUCTURAL OXOVANADIUM(V) COMPLEXES WITH HYDRAZONE LIGANDS
Two new isostructural methoxide-bridged dimeric oxovanadium(V) complexes [VO(L1)(OMe)]2 (1) and [VO(L2)(OMe)]2 (2), where L1 and L2 are the deprotonated forms of 3-bromo-N?-[1-(2-hydroxyphenyl)ethylidene]benzohydrazide (H2L1) and 3-chloro-N?-[1-(2-hydroxyphenyl)ethylidene]benzohydrazide (H2L2) respectively, are synthesized and characterized by elemental analyses, IR spectra, and single crystal X-ray determination. Both crystals crystallize in the triclinic space group P-1. For 1, a = 7.5237(15) ?, b = 10.846(3) ?, c = 11.195(3) ?, a = 84.143(3)°, b = 72.244(3)°, g = 77.869(3)°, V = 849.9(4) ?3, Z = 1, R1 = 0.0634, wR2 = 0.1373. For 2, a = 7.493(2) ?, b = 10.740(3) ?, c = 11.109(3) ?, a = 84.569(2)°, b = 71.783(2)°, g = 79.822(2)°, V = 835.0(4) ?3, Z = 1, R1 = 0.0511, wR2 = 0.1076. Each V atom in the complexes is octahedrally coordinated.
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Each V atom in the complexes is octahedrally coordinated. <...> INTRODUCTION Oxovanadium complexes with multi-dentate ligands have been extensively investigated in recent years with respect to their remarkable efficiency as insulin mimetic compounds [ 1—3 ]. <...> As an extension work on the construction of new oxovanadium complexes with potential insulin mimetic properties, two isostructural oxovanadium(V) complexes derived from the similar hydrazone ligands 3-bromo-N-[1-(2-hydroxyphenyl)ethylidene]benzohydrazide (H2L1; Scheme 1) and 3-chloro-N-[1-(2-hydroxyphenyl)ethylidene]benzohydrazide (H2L2; Scheme 1) were synthesized and characterized. -. 528 – 532 Scheme 1. <...> A mixture of 3-bromobenzaldehyde (0.215 g, 1 mmol) and 1-(2-hydroxyphenyl)ethanone (0.136 g, 1 mmol) in 50 ml of methanol was stirred at room temperature for 1 h. 80 % of the solvent was evaporated by distillation, and the mixture was cooled to room temperature, giving colorless microcrystals. <...> The product was filtered out and washed with methanol. <...> Evaporation of the solution at room temperature yielded deep brown block-shaped single crystals after a few days. <...> The hydrogen atoms were included in the final refinement on the calculated positions riding on their parent atoms. <...> The two oxovanadium(V) complexes were readily synthesized by the reaction of VO(acac)2 with hydrazone ligands in methanol. <...> The deep brown single crystals were obtained by recrystallization of the complexes in methanol. <...> The two structures are isostructural methoxide-bridged centrosymmetric dimeric oxovanadium(V) complexes with the VᄷV distances of 3.400(1) Е for 1 and 3.369(1) Е for 2. <...> The tridentate hydrazone ligands coordinate to the V atoms through the phenolate O, imino N, and enolic O atoms. <...> The coordinate bond lengths and angles in the complexes are comparable to each other and are also comparable 530 J. YU Table 1 Crystallographic and experimental data for the complexes 1 2 Chemical formula Fw 858.3 Crystal shape / colour Crystal size, mm Crystal system Space group a, b, c, Е h, i, t, deg. <...> CONCLUSIONS In summary, the present paper reports the synthesis and characterization of two new isostructural centrosymmetric dimeric oxovanadium(V) complexes with similar hydrazone compounds. <...> Single crystal X-ray diffraction <...>
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