A new Schiff base ligand (E)-2,6-dimethoxy-4-((quinolin-3-ylimino)methyl)phenol (HL) and its Cu(II), Co(II), Ni(II) and Zn(11) metal complexes have been synthesized and characterized by various spectroscopic (UV-visible, IR, NMR and mass), SEM and magnetic susceptibility measurement. The ligand (HL) have been synthesized by condensation of 4-hydroxy-3,5-dimethoxybenzaldehyde and 3-aminoquinoline. Based on electronic spectral data and magnetic susceptibility measurement the tetrahedral geometry is proposed for all the complexes. The ligand and metal complexes are screened for their antimicrobial activities against bacteria (Staphylococcus aureus, Escherichia coli) and antifungal activity against the fungi (Candida albicans). Further, the ligand and its Cu(II) complex are also screened for anticancer activity on human breast (MCF7) cancer cell lines by the MTT assay method. Interestingly, Cu(II) complex shows better anticancer activity than the free Schiff base ligand. The in vitro anti-inflammatory and anti-diabetic activities of the ligand and Cu(II) complex are studied. The Cu(II) complex show higher inhibition activity than that of the free ligand.
Four new mononuclear manganese(III) complexes namely 1, 2, 3 and 4 of salen-type ligands H2L 1-H2L 4 (ligands were obtained in situ via Schiff-base condensation of 2-formyl-6-hydroxymethyl-4-methylphenol and amines cyclohexane-1,2diamine, 2-methylpropane-1,2-diamine, propane-1,2-diamine and ethane-1,2-diamine, respectively) have been synthesised and characterised by routine physicochemical techniques. 1 is further characterised by X-ray single crystal structure analysis. Catalytic efficiencies of the complexes as epoxidation catalysts (substrates: styrene and (E)-stilbene; terminal oxidants: PhIO/NaOCl; solvent: MeCN /dicholorometane) and as catalysts for oxidation of catachol (substrates: 3,5-di-tertbutylcatechol (3,5-DTBC); solvent: methanol) have been evaluated. In both cases the catalytic efficiency increases on going from 4-1 although the actual mechanisms in those two catalytic reactions are completely different. However, the observations have been rationalized on the basis of steric and electronic factors exerted by the alkyl substituents present on the imine back-bone of the salen-type ligands. This study also verifies that there is at least another active epoxidizing species, [Cl–O–Mn(III)(salen)X] in addition to the discrete Mn(V)=O(salen) species in epoxidation of olefins depending upon the terminal oxidants employed.
Nickel-Iron bimetallic oxide nanoparticles have been synthesized in ethylene glycol using microwave irradiation technique. The microwave assisted synthesized Nickel and iron oxide nanoparticles are combined together in 1:1 molar ratio and treated under microwave irradiation followed by calcination to get Ni-Fe bimetallic oxide. The structure and composition of nanoparticles are characterized by UV-visible spectroscopy, FT-IR, X-ray diffraction (XRD), energy dispersion spectroscopy (EDS) and transmission electron microscopy (TEM) techniques. The empirical formula of the nanoparticle is found as Ni1Fe1.6O2.9 at 500 degrees C, Ni1Fe1.5O2.6 at 700 degrees C and Ni1Fe2O2.7 at 900 degrees C by varied reaction conditions. A maximum absorbance of 357.67 nm is observed in UV-visible spectrum. The average size of particles in all cases is found to be similar to 30 nm as confirmed from TEM images. Antibacterial and antifungal studies have not shown any appreciable results.
Reactions of bis(acetylacetonato)aluminum(III)-di-(mu-isopropoxo)-di-isopropoxoaluminum(III) (A) with a variety of alkylenedithiophosphoric acids in different molar ratio yield products of the type [(CH3COCHCOCH3)(2) Al(mu-OPri)(2) Al{S(S)P(O-G-O)(n) (OPri)(2-n)] (1-9) {where G= C(CH3)(2)C(CH3)(2) , n=1[1], n=2[2]; -CH2CH(C2H5), n=1[3], n=2[4]; CH2CH(CH3), n=1[5] , n=2 [6] ; C(CH3)(2)CH2CH(CH3), n=1[7]; CH(CH3)CH(CH3) n=1[8], n=2 [9]} . Progress of the reaction is monitored by estimating liberated 2-propanol in benzene-2-propanol azeotrope by oxidimetric method. All pale coloured viscous products were soluble in common organic solvents and are characterized by elemental analyses, FT-IR and NMR (H-1 and C-13{H-1} NMR) spectral studies. Molecular weight measurements in refluxing anhydrous benzene indicated binuclear nature of the complexes. Al-27 NMR spectra of two of the derivatives, (1) and (2), suggested the presence of aluminium(III) atoms in different coordination states. P-31 NMR spectra of the representative derivatives (1) and (2) exhibited only a single peak at 95.71 and 90.59 ppm, respectively, suggesting tetra-coordination around phosphorus atom and a bidentate mode of chelation of the dithio ligand. Sol-gel transformation of Al(OPri)(3) and [(CH3COCHCOCH3)(2) Al(mu-OPri)(2)Al(OPri)(2)] (A) followed by sintering at similar to 850 degrees C yield alumina (a) and (b), respectively. The powder X-ray diffraction patterns, SEM images and FT-IR spectral studies of (a) and (b) has indicated formation of nano-crystallites of theta -Al2O3 [PDF # 110517] in both the cases. The energy band gaps of 4.78 eV and 5.01 eV for (a) and (b), respectively are obtained from the absorption spectra.
Pd based bimetallic catalysts, Pd-M, (M=Cu, Ag, and Au) supported on TiO2 P-25, have been prepared by chemical reduction with glucose and characterized by XRD, TEM, XPS, DRS, TPR and H2TPD. Activity for the conversion of cirmamaldehyde (CAL) and selectivity to hydro-cinnamaldehyde (HCAL), cirmamyl alcohol (COL) and hydrocinnamyl alcohol (HCOL) have been evaluated in the temperature range of 120-140 degrees C for 1 h and 10 bar hydrogen pressure. For comparison, monometallic Cu, Ag and Au (1% w/w in each case) catalysts supported on TiO2 P-25 have been prepared and evaluated. DRS and XPS studies reveal nanoscale alloy formation and re-distribution of charges in bimetallic catalysts. Bimetallic Pd-Cu displays higher CAL conversion compared to Pd-Ag and Pd-Au. Besides the favourable electronic and ensemble effects, availability of reactive hydrogen on Pd-Cu, as revealed by the lowest hydrogen desorption temperature, is an additional factor that contributes towards the higher activity of Pd-Cu. Bimetallic catalysts are stable up to five reaction cycles, without any loss of Pd or structural integrity.
