New complexes of Mo(V) with Schiff bases: Crystal structure of butylammonium di-μ-oxo-μ-acetato-bis[(N-butylsalicylideniminato-N,O)oxomolybdenum(V)] benzene, acetic acid solvate

New mononuclear and binuclear oxomolybdenum(V) complexes containing NN chelator: Syntheses, DFT calculations, interaction with BSA protein and in vitro cytotoxic activity

A neutral bidentate ligand 2-(3-methyl-5-phenyl pyrazol-1-yl) benzthiazole (L) has been synthesized by refluxing equimolar proportions of 2-hydrazino benzthiazole and benzoyl acetone in ethanol. The ligand acts in a NN donor fashion and forms stable mononuclear, MoOX₃L [L = Ligand, X = Cl (1), Br (2)] and binuclear Mo₂O₄X₂L₂ [L = Ligand, X = Cl (3), Br (4)] complexes with molybdenum(V). The ligand and complexes are thoroughly characterized by elemental analyses, IR, UV-Vis spectroscopy, EPR study, magnetic susceptibility, thermogravimetry and cyclic voltammetry. Magnetic moment measurements reveal that the mononuclear complexes are paramagnetic while the binuclear complexes are diamagnetic in nature. EPR studies also confirm the presence of a mononuclear Mo(V) moiety in the complexes. Relevant Density Functional Theory (DFT) calculations have been carried out to determine the structures of the synthesized compounds. The binding mode and mechanism of interaction of the synthesized compounds with bovine serum albumin (BSA) were studied by concentration dependent absorption and fluorescence titration experiments. The ligand and complexes 1-4 are screened for their potential in vitro anticancer activities against three different human cancer cell lines, namely, cervix adenocarcinoma epithelial cells (HeLa), renal carcinoma cells (SK-RC-45) and breast adenocarcinoma cells (MCF-7). The oxomolybdenum(V) complexes are found to exhibit higher anticancer potency towards the cancer cells than the free ligand. Also, structure activity relationship (SAR) studies of this new series of oxomolybdenum(V) complexes indicate that the anticancer activity is to some extent dependent on the electronic effects of the halogen atom coordinated to the molybdenum centre.

Molybdenum complexes with a μ-O{MoO2}2 core: their synthesis, crystal structure and application as catalysts for the oxidation of bicyclic alcohols using N-based additives

Binuclear molybdenum(vi) complexes with a μ-O{MoO₂}₂ core as catalysts for the oxidation of bicyclic alcohols (fenchyl alcohol and isoborneol), using 30% H₂O₂ as the oxidant in the presence of NEt₃ as the additive, are reported.

One-step preparation of flower-like poly(styrene-co-zwitterionic ionic liquid) microspheres with hierarchical structures for supported acidic heterogeneous catalysts

Novel flower-like poly(styrene-co-zwitterionic ionic liquid) microspheres with hierarchical structures for supported acidic heterogeneous catalysts show excellent catalytic activities for the esterifications, acetalizations and transesterifications.

Synthesis and characterization of oxidomolybdenum(V) and dioxidomolybdeum(VI) complexes derived from isonicotinoyl(2-hydroxy-3-methoxybenzylidene)hydrazide

Several novel complexes of oxidomolybdenum(V) and dioxidomolybdenum(VI) were synthesized with the Schiff base, 3- methoxy salicylaldehydeisonicotinoylhydrazone (HL) derived from 3- methoxy salicylaldehyde and isonicotinoylhydrazide. The complexes were characterized by elemental analyses, molar conductance and magnetic susceptibility, as well as IR, 1H-NMR, Fmass and UV-Vis spectral studies. The complexes have the general formulae [MoO(L)XCl] and [MoO2(L)X], where X=NO3 or ClO4. The IR spectra of these complexes indicate that the ligand (HL) acts as a monoanionic tridentate chelating agent. The spectra indicate the monodentate mode of coordination for the nitrate and perchlorate groups. The X-ray diffraction studies of [MoO(L)NO3Cl] correspond to an orthorhombic crystal lattice with unit cell dimensions a = 15.49 ?, b = 12.44 ? and c = 10.11 ?. All the complexes were found to have distorted octahedral geometry. Thermal studies of the complex [MoO2(L)NO3] showed that it was stable up to 240 ?C, above which it started to decompose. The optimized geometry of ligand and one of its complexes, [MoO(L)NO3Cl], have been obtained by a molecular mechanics method. Antibacterial studies of the present complexes show that the oxidomolybdenum(V) complexes were more potent bactericides than the ligand and the dioxidomolybdenum(VI) complexes.

Molybdenum oxo and imido complexes of beta-diketiminate ligands: synthesis and structural aspects

Treatment of [MoO2(eta2-Pz)2] (Pz = 3,5-di-tert-butylpyrazolate) with the diketiminate ligand NacNacH (NacNac = CH[C(Me)NAr]2-, Ar = 2,6-Me2C6H3) at 55 degrees C leads under reduction of the metal to the formation of the dimeric molybdenum(V) compound [{MoO2(NacNac)}2] (1). The compound was characterized by spectroscopic means and by X-ray crystal structure analysis. The dimer consists of a [Mo2O4]2+ core with a short Mo-Mo bond (2.5591(5) A) and one coordinated diketiminate ligand on each metal atom. The reaction of [MoO2(eta2-Pz)2] with NacNacH in benzene at room temperature leads to a mixture of 1 and the monomeric molybdenum(VI) compound [MoO2(NacNac)(eta2-Pz)] (2). From such solutions, yellow crystals of 2 suitable for X-ray structural analysis were obtained revealing the coordination of one bidentate NacNac and one eta2-coordinate Pz ligand. This renders the two oxo groups inequivalent. Further high oxidation state molybdenum compounds containing the NacNac ligand were obtained by the reaction of [Mo(NAr)2Cl2(dme)] (Ar = 2,6-Me2C6H3) and [Mo(N-t-Bu)2Cl2(dme)] (dme = dimethoxyethane) with 1 equiv of the potassium salt NacNacK forming [Mo(NAr)2Cl(NacNac)] (3) and [Mo(N-t-Bu)2Cl(NacNac)] (4), respectively, in good yields. The X-ray structure analysis of 3 revealed a penta-coordinate compound where the geometry is best described as trigonal-bipyramidal.