Saadia A. Ali

Chromium, Molybdenum and Ruthenium Complexes of 2-Hydroxyacetophenone Schiff Bases

Interaction of the Schiff base 2-hydroxyacetophenonepropylimine (happramH) with M(CO)6, M=Cr or Mo under reduced pressure gave the dicarbonyl complex M(CO)2(happramH)2. The complex MoO(happram)2 was isolated from the reaction of Mo(CO)6 and happramH in air. Ru3(CO)12 and RuCl3 reacted with the Schiff base bis-(2-hydroxyacetophenone)ethylenediimine (hapenH2) to give Ru(CO)2(hapenH2) and [RuCl2(hapenH2)]Cl. Elemental, spectroscopic and magnetic studies of the reported complexes revealed the proposed structures. The thermal properties of the complexes were investigated by thermogravimetric techniques. Cyclic voltammetry of the complexes showed tautomeric redox processes due to ligand-based reduction and metal-based oxidation.

Chromium, molybdenum and ruthenium complexes of chloranilic acid

Chloranilic acid (H2CA) reacts with Cr(CO)6 and CrCl3 to give the tris derivatives Cr(H2CA)3 and Cr(HCA)3. Spectroscopic measurements on the two complexes reveal that the ligand–metal bond is of the semiquinone type. Susceptibility determinations showed effective magnetic moments of 1.82 and 1.07 μB. Examination of Cr(H2CA)3 by cyclic voltammetry revealed two redox reactions due to tautomeric interconversion through electron transfer. Boiling Mo(CO)6 with H2CA in air gave MoO3(HCA) in which the molybdenum atom is in the + 5 oxidation state. The i.r. spectrum of the MoO3(HCA) displayed bands due to terminal M=O bonds. The cluster compound Ru3(CO)12 reacted with H2CA to give Ru3(CO)10(μ-H)(HCA), the i.r. spectrum of which revealed that the ligand is bound to the metal as a catechol moiety. The spectroscopic and magnetic studies of the molybdenum and ruthenium complexes confirmed the proposed structures.

Thermal studies of chromium, molybdenum and ruthenium complexes of chloranilic acid

Abstract Chromium, molybdenum and ruthenium complexes of chloranilic acid (H 2 CA) were investigated by the thermogravimetric (TG) technique. The TG plot of Cr(H 2 CA) 3 showed three decompositions in the temperature range 336–802°K. On the other hand, the TG plot of MoO 3 (HCA) complex displayed successive weight losses in four steps covering the temperature range 350–1278°K. The thermal decomposition of the cluster compound Ru 3 (CO) 10 (μ-H)(HCA) occurred in three steps within the decomposition temperature range 302–764°K. Calculation of the reaction order of decompositions of the three complexes revealed that they follow first-order kinetics. The thermodynamic parameters for the different decomposition steps of the complexes were also determined from their DTG plots.

Synthesis, characterization and biological activities of some new chromium molybdenum and tungsten complexes with 2,6-diaminopyridine

The reactions of [M(CO)6], M=Cr, Mo, W with 2,6-diaminopyridine (dap) in ethanol was carried out under sun light and microwave irradiation routes of synthesis and compared with the traditional thermal reflux method. All routes resulted in the formation of the binuclear oxo complexes with the general formulas [M2(O)4(dap)2]. The prepared complexes were characterized using elemental analysis, IR, 1HNMR, mass spectrometry and magnetic measurement. The biological activity of dap and its complexes as antibacterial and antifungal reagents have been screened.

Novel chromium and molybdenum complexes of a dimerized isonicotinic acid hydrazide

Sunlight irradiation of [M(CO)6], M = Cr and Mo with isonicotinic acid hydrazide (inh) was investigated. The photochemical process resulted in dimerization of inh with elimination of a hydrazine molecule to give N′-isonicotinoylisonicotino hydrazide (ininh). Two complexes with molecular formulas [MO2(ininh)] were isolated and characterized by elemental analysis, infrared, mass and 1H NMR spectroscopy. The UV-vis spectra of the complexes in DMSO showed visible bands due to ligand-to-metal charge transfer. Thermal properties of the complexes were investigated by TG thermogravimetry.

Synthesis and characterization of new chromium, molybdenum and tungsten complexes of 2-[2-(methylaminoethyl)] pyridine.

A green chemistry route of synthesis using direct sunlight irradiation for the reactions of [M(CO)(6)] M=Cr, Mo or W with 2-[2-(methylaminoethyl)] pyridine (maepy) in THF. The reactions resulted in the formation of the oxo complex [Cr(2)(O)(4)(maepy)(2)] (1) and the tetracarbonyl complexes [Mo(CO)(4)(maepy)] (2) and [W(CO)(4)(maepy)] (3). The prepared complexes were characterized by elemental analysis, IR, NMR, mass spectrometry and magnetic measurement. The complexes (1-3) were further investigated by thermogravimetric technique (TG). The biological activity of maepy and complexes as antibacterial and antifungal reagents have been investigated.

Structural studies of new group 6 complexes of salicylidene-2-aminopyridine

Interaction of salicylidene-2-aminopyridine (Hsap) with [M(CO)6], M = Cr, Mo and W, in THF under sunlight resulted in formation of dinuclear complexes [Cr2O4(sap)], 1, [Mo2O4(sap)], 2, and [W2O5(sap)2], 3. Elemental analysis, spectroscopic and magnetic studies of the reported complexes revealed the proposed structures. Magnetic studies of 1 and 2 suggested that the two metal centers have +3 and +6 formal oxidation states, while the tungsten complex 3 has +6 formal oxidation state with d0 electron configuration. The thermal properties of the complexes were investigated by thermogravimetry.

Reactions of group 6 metal carbonyls with salicylaldehyde isonicotinic acid hydrazone

Sunlight irradiation of the reactions of [M(CO)6], M = Cr, Mo and W with salicylaldehyde isonicotinic acid hydrazone (H2salnah) in THF were investigated. Interaction of [Cr(CO)6] with H2salnah resulted in formation [Cr2O2(H2salnah)2]. The corresponding reactions of molybdenum and tungsten carbonyls yielded dinuclear oxo complexes [M2O6(H2salnah)]. All complexes were characterized by elemental analysis, IR, mass spectrometry and 1H NMR spectroscopy. The IR spectra of complexes exhibited bands due to either terminal or bridged metal oxygen bonds. Magnetic measurement of [Cr2O2(H2salnah)2] showed it has paramagnetic characteristics with high spin d4 configuration and μeff of 1.27 BM. Electronic spectra of the complexes in DMF displayed visible bands due to ligand-to-metal charge transfer. Thermal properties of the complexes were investigated by thermogravimetry technique.

SYNTHESIS, SPECTRAL, MAGNETIC, AND THERMAL STUDIES OF SOME COMPLEXES OF TRANS-1, 2-DIAMINOCYCLOHEXANE-N, N, N′, N′-TETRAACETIC ACID

Solid complexes of trans-1, 2-diaminocyclohexane-N, N, N′, N′-tetraacetic acid with Cr(III), Co(II), Ni(II) and Cu(II) ions were synthesized. The complexes were characterized by elemental analyses, magnetic measurements, IR, UV-Vis and mass spectroscopy. A detailed study of their thermal analysis was carried out.