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A series of norephedrine-based Schiff bases (1a-6a and 1b-6b) were synthesized by reacting substituted salicylaldehydes with d-norephedrine or l-norephedrine. The structure of these compounds was confirmed by elemental analyses and spectroscopic techniques. The molecular structures of 5a and 6a have been determined by X-ray crystallography, which revealed that the compounds are in the oxoamino form, with bent intramolecular N-H···O (N···O ≈ 2.58 Å) hydrogen bonds and that they are associated in dimers bridged by linear intermolecular O-H···O (O···O ≈ 2.69 Å) hydrogen bonds. The density functional theory calculations on 5a confirmed that the oxoamino form is more stable than the phenolimino form by 12.2 kcal/mol. All the compounds were evaluated for their antibacterial activity using resazurin dye as indicator by twofold dilution method against four bacteria namely, Bacillus subtilis (NCIM2718), Staphylococcus aureus (NCIM5021), Escherichia coli (NCIM2931), and Proteus vulgaris (NCIM2813)., (© 2011 John Wiley & Sons A/S.)

A series of new hexa-coordinated ruthenium(III) complexes of the type [Ru(X)(2-atmp-ba)(EPh3)] (where H2-2-atmp-ba=N,N'-bis(2-aminothiophenol)benzoylacetone; X=Cl or Br; E=P or As) have been prepared by reacting [RuX3(EPh3)3] (where X=Cl or Br; E=P or As) with tetradentate Schiff base ligand (H2-2-atmp-ba) in 1:1 molar ratio. The complexes have been characterized by elemental analyses, Infra red, electronic, electron paramagnetic resonance spectroscopy and cyclic voltammetry. In order to confirm the coordination and structure of the complexes extended X-ray absorption fine structure spectroscopy (EXAFS) studies have been carried out. Based on the above data, an octahedral structure has been confirmed for the complexes. The new complexes were also screened for their antibacterial properties.

A Co(III) Schiff base complex with the formula [Co(L)]Cl · HO ( I) (L = monoanionic tridentate Schiff base ligand derived from salicylaldehyde and ethylene diamine) has been synthesized and characterized by elemental analysis and spectroscopic techniques. The structure of I was confirmed by single crystal X-ray diffraction studies (CIF file CCDC no. 1009967), which showed the presence of two Schiff base molecules in an octahedral fashion. The complex has been screened for its in vitro antibacterial and anticancer activities. Complex I was found to be more active in anti-microbial and anti-cancer activity than the ligand. [ABSTRACT FROM AUTHOR]

Abstract: Air stable Ni(II) and Pd(II) complexes viz. [Ni(LS)(P(OEt)3)] (1), [Ni(LN)(P(OEt)3)] (2), [Pd(LS)(P(OEt)3)] (3) and [Pd(LN)(P(OEt)3)] (4) [where LS and LN are dianions of N–(2–mercaptophenyl)salicylideneimine and N–(2–mercaptophenyl)naphthylideneimine respectively] have been synthesized and characterized by analytical and spectral (electronic, FT–IR, 1H, 13C and 31P NMR) methods. The 1H–31P HMBC spectrum established the coupling of phosphorus with the azomethine proton of the Schiff base and the aliphatic protons of triethylphosphite. Novel Ni(II) and Pd(II) complexes exhibited good catalytic activity in Kumada–Tamao–Corriu and Suzuki–Miyaura coupling reactions respectively. [Copyright &y& Elsevier]

Abstract: Complexes of the type [Ru(CO)(EPh3)(B)(L)] (E=P or As; B=PPh3, AsPh3, py or pip; L=dianion of the Schiff bases derived from thiosemicarbazone with acetoacetanilide, acetoacet-o-toluidide and o-chloro acetoacetanilide) have been synthesized from the reactions of equimolar amounts of [RuHCl(CO)(EPh3)2(B)] and Schiff bases in benzene. The new complexes have been characterized by analytical and spectral (IR, electronic, NMR) data. The arrangement of PPh3 groups around ruthenium metal was determined from 31P NMR spectra. An octahedral structure has been assigned for all the new complexes. All the complexes exhibited catalytic activity for the oxidation of benzyl alcohol and cyclohexanol in presence of N-methylmorpholine-N-oxide as co-oxidant. The complexes also exhibited antibacterial activity against E. coli, Aeromonas hydrophilla and Salmonella typhi. The activity was compared with standard streptomycin. [Copyright &y& Elsevier]

Abstract: A series of new mixed ligand hexacoordinated ruthenium(III) Schiff base complexes of the type [RuX2(EPh3)2(LL′)] (X=Cl, E=P; X=Cl or Br, E=As and LL′=anion of the Schiff bases derived from the condensation of 2-hydroxy-1-naphthaldehyde with aniline, 4-chloroaniline, 2-methyl aniline and 4-methoxy aniline) are reported. All the complexes have been characterized by analytical and spectral (IR, electronic and EPR) data. The redox behavior of the complexes has also been studied. The complexes exhibit catalytic activity in the oxidation of benzyl alcohol to benzaldehyde in the presence of N-methyl morpholine-N-oxide (NMO). An octahedral structure has been proposed for all of the complexes. [Copyright &y& Elsevier]

The synthesis and characterization of several hexa‐coordinated ruthenium(III) complexes of the type [RuX 2 (EPh 3 )(L)] (E=P or As; X=Cl or Br; L=monobasic tridentate ligand derived by the condensation of o ‐phenylene diamine or ethylene diamine with salicylaldehyde or o ‐hydroxyacetophenone) are reported. Elemental analyses, IR, electronic, EPR, and cyclic voltammetric data of the complexes are discussed. An octahedral geometry has been tentatively proposed for all the complexes. The new complexes were found to be effective catalysts for the oxidation of benzyl alcohol and cyclohexanol to benzaldehyde and cyclohexanone, respectively, using N‐methylmorpholine‐N‐oxide as a co‐oxidant. [ABSTRACT FROM AUTHOR]

Novel Schiff bases derived from the treatment of mercapto-diamino pyrimidine with two different aldehydes are characterized using elemental analysis, single crystal X-ray diffraction and 1 H NMR spectroscopy. The pharmacological action of the synthesized compounds viz ., antimicrobial, anticancer and antitubercular activities is studied. The Schiff bases show a very good activity against various test pathogens. DNA and β-CD binding interactions of the compounds are studied using UV–Visible absorption and fluorescence spectral measurements. The binding constants of the compounds towards β-CD are in the order of 10 3 to 10 4 . Molecular docking is done using MOE program on the 3D structure of the enzymes, viz ., human thymidylate synthase complexed with dump and raltitrex, candida albicans N-myristoyltransferasepeptidic inhibitor, catalytic domain of protein kinase pKnb from mycobacterium tuberculosis in complex with mitoxantrone, pare, topoisomerase atpase inhibitor, E. coli and lactobacillus casdihydrofolatereductase. The MIC/IC 50 values of the Schiff bases are compared with the glide scores from the molecular docking studies. The number of hydrogen bonding interactions between the Schiff bases and amino acid residues are also reported. [ABSTRACT FROM AUTHOR]

Abstract: Reactions of H2L with [RuHCl(CO)(PPh3)3] in toluene gives [Ru(L)(CO)(PPh3)2] (L = binegative tridentate ONS donor ligand derived from salicylaldehyde/4-substituted salicylaldehyde/2-hydroxy-1-naphthaldehyde and o-aminothiophenol) at room temperature. All the complexes were characterized by elemental analyses and UV–Visible, FT-IR, 1H, 1 3C and 31P NMR spectroscopic methods. 1H–1H COSY and 1H–31P HMBC spectra of [Ru(L4)(CO)(PPh3)2] have been studied. 1H–31P HMBC spectrum established the coupling of phosphorus atoms with azomethine proton. The single crystal X-ray analysis of [Ru(L5)(CO)(PPh3)2] revealed that Schiff base ligand is coordinated to the metal center, via dissociation of the two acidic protons, as a dianionic tridentate ONS donor and that ruthenium(II) ion adopts octahedral coordination with the phosphorus atoms in trans-disposition. Ruthenium complexes have been used in conjunction with N-methylmorpholine-N-oxide (NMO) for the catalytic oxidation of various alcohols at room temperature. Benzylic primary and secondary alcohols are oxidized in good to excellent yields, and aliphatic and cyclic alcohols give carbonyl compounds in moderate yields. [Copyright &y& Elsevier]

Abstract: Five mononuclear nickel(II) complexes, viz. [Ni(L1)(PPh3)] (1), [Ni(L2)(PPh3)] (2), [Ni(L3)(PPh3)] (3), [Ni(L4)(PPh3)] (4) and [Ni(L5)(PPh3)] (5) (where L1, L2, L3, L4 and L5 are dianions of N-(2-mercaptophenyl)salicylideneimine, 5-methyl-N-(2-mercaptophenyl)salicylideneimine, 5-chloro-N-(2-mercaptophenyl)salicylideneimine, 5-bromo-N-(2-mercaptophenyl)salicylideneimine and N-(2-mercaptophenyl)naphthylideneimine, respectively), have been synthesized and characterized by means of elemental analysis, electronic, IR, 1H, 13C and 31P NMR spectroscopy. Single crystal X-ray analysis of two of the complexes (1 and 5) has revealed the presence of a square planar coordination geometry (ONSP) about nickel. The crystal structures of the complexes are stabilized by intermolecular π–π stacking between the ligands (L) and by various C–H···π interactions. [Copyright &y& Elsevier]