Synthesis and characterization of palladium (II) complex of Schiff base ligand: C-S bond cleavage and catalytic activity

Reaction of ligand, L-CH2Ph with Pd(CH3CN)(2)Cl-2 in acetonitrile in presence of PPh3 and subsequent addition of NaClO4 yielded Pd(II) complex, [Pd(L)(PPh3)](ClO4) 1 due to the S-C (CH2Ph) bond cleavage during complexation. Complex 1 was characterized by spectral analysis and the structure was authenticated by single crystal X-ray diffraction. The diffraction analysis revealed that the monoanionic ligand binds with palladium (II) in (N, N, S) fashion in a distorted square planar geometry where the fourth position is occupied by one tri phenyl phosphine group. One ClO4- ion satisfies the charge of the former aggregate, [Pd(L)(PPh3)](+). The complex [Pd(L)(PPh3)](ClO4), 1 exhibits a very good catalytic activity towards C-C bond formation. (C) 2015 Elsevier B.V. All rights reserved

Synthesis, crystal structure, spectral properties and catalytic activity of binuclear copper(II), mononuclear nickel(II) and cobalt(III) complexes containing Schiff base ligand

Newly designed tridentate ligand, HL 1 derived from 2-(benzylthio) aniline and 2-hydroxy-1-naphthaldehyde, upon reaction with Cu(II), Ni(II) and Co(III) nitrate separately in methanol yielded binuclear Cu(II) complex, [Cu-2(L)(2)(NO3)(2)](2), and mononuclear [Ni(L)(2)] 3 and [Co(L)(2)](NO3) 4 which were characterized by spectral data and authenticated by single crystal X-ray diffraction of 2 and 3. The diffraction analysis revealed that the ligand binds to metals in (O, N, S) fashion. Single crystal X-ray diffraction studies confirmed that the [Cu-2(L)(2)(NO3)(2)] complex consist of centrosymmetric binuclear entities containing square-pyramidal copper(II) ions bridged through the phenoxo oxygen atoms. The emission and redox properties of both the ligand and corresponding complexes were examined. The redox property of the complexes has been qualitatively explained by single point DFT calculations. The catalytic activities of Cu(II) complex [Cu-2(L)(2)(NO3)(2)] towards oxidation of benzyl alcohol derivatives to carbonyl compounds was tested using H2O2 as the oxidant. (C) 2014 Elsevier B. V. All rights reserved

Design, synthesis and properties of orthopalladated complexes: proheterogeneous catalyst

The reaction of multidentate ligand, 3 ((E) (2 ((E) 4 aryldiazenyl)phenylimino)methyl)benzene 1,2 diol, H2L (H2L1, 1a; H2L2, 1b and H2L3, 1c) and (E) 2 ((2 (aryldiazenyl)phenylamino)methyl)phenol, HA (HA1, 3a; HA2, 3b and HA3, 3c) [where H represents the dissociable protons upon complexation, and aryl groups of H2L and HA are phenyl for H2L1 and HA1, p methylphenyl for H2L2 and HA2, and p chlorophenyl for H2L3 and HA3], with Na2PdCl4 separately afforded orthometallated complexes [(L)Pd], (2a, 2b and 2c) and [(A)PdCl] (4a, 4b and 4c) respectively. In the case of [(L)Pd], the deprotonated L2 ligands bind pal ladium (II) in a tetradentate (C,N,N,O) fashion whereas in the case of [(A)PdCl], the deprotonated A ligands bind Pd(II) in tridentate (C,N,N) manner. X ray structures of [(L1)Pd], (2a) and [(A1)PdCl] (4a) were determined to confirm the molecular structures. Both the complexes 4a and 5a exhibited catalytic activ ity toward Suzuki and Heck reactions. Conversion of [(A)PdCl] to its oxidized form upon ligand oxidation is reported

Synthesis, crystal structure, spectral properties and catalytic activity of a binuclear copper(II) complex containing a Schiff base ligand

The newly designed multidentate ligand HL, derived from 2-(benzylthio)aniline and 2-hydroxy-5-methylbenzene-1,3-dialdehyde, upon reaction with Cu(II) perchlorate in methanol yielded the binuclear Cu(II) complex [Cu-2(L)(mu-OH)](ClO4)(2) (1), which was authenticated by single crystal X-ray diffraction. The diffraction analysis revealed that the ligand binds each of the two Cu(II) centers in an (O, N, S) fashion in a distorted square pyramidal geometry where the two copper centers are bridged by mu-phenoxo and mu-hydroxo oxygen atoms. The apical position of one copper center is coordinated by one perchlorate ion and the other center by a water molecule. The packing of the molecule is stabilized through OH2 center dot center dot center dot O hydrogen bonds, mediated through solvent water and perchlorate anions. The emission and redox properties of both the ligand and the complex were examined. The electronic spectra and redox properties of the complex have been explained with DFT computations. The complex [Cu-2(L)(mu-OH)](ClO4)(2) shows very good catalytic activities towards the oxidation of benzyl alcohol to benzaldehyde and organic thioethers to the corresponding sulfoxide and sulfones using H2O2 as the oxidant. (C) 2013 Elsevier Ltd. All rights reserved

Synthesis, characterization, structure and properties of copper and palladium complexes incorporating azo-amide ligands

The reaction of the multidentate ligand N-(2-(aryldiazenyl)phenyl)picolinamide, HL (3a, 3b and 3c) [HL is ArN = NC6H4NHC(O)Py, where Ar is C6H5 for HL1 (3a), p-MeC6H4 for HL2 (3b) or p-ClC6H4 for HL3 (3c), and Py stands for pyridyl], with Cu(CH3COO)(2)center dot H2O and Na2PdCl4 separately afforded the complexes [(L)(2)Cu] (4a, 4b and 4c) and [(L)PdCl] (5a, 5b and 5c) respectively, where the deprotonated ligand L- binds copper(II) and palladium(II) in a tridentate (N,N,N) fashion. X-ray structures of [(L-3)(2)Cu] (4c) and [(L-1)PdCl] (5a) were determined to confirm the molecular structures. The newly synthesized complex 4a exhibits catalytic activity toward the oxidation of alcohols to the corresponding carbonyl compounds and oxidation of organic thioethers to sulfoxide and sulfone, whereas the complex 5a is an active catalyst for Suzuki and Heck reactions. (C) 2014 Elsevier Ltd. All rights reserved

Synthesis, characterizations and structure of orthometallated Pt(II) and Pt(IV) complexes: Oxidative addition to C,N,N,O coordinated Pt(II) complexes

Reactions of 2-(arylazo)-1-N-salicylidene phenylamine, H2L, 1, [H represents the dissociable protons upon complexation], with K2PtCl4 afforded orthometallated complexes of composition [Pt(L)], 2 where the Pt(II) is coordinated by the tetradentate (C,N,N,O) ligand, L2-. Reaction of the precursor complex [Pt(L)] with I-2 afforded octahedral complexes of composition [PtI2(L)], 3. All the complexes were characterized unequivocally. X-ray crystal structure of [Pt(L-1)] and [Pt I-2(L-1)] have been determined. (C) 2014 Published by Elsevier Ltd

Synthesis, crystal structures, spectral studies and reactivity of square planar copper(II) complexes containing Schiff base ligand

The reactions of HL1 [2-((2-(benzylthio)phenylimino)methyl)phenol] and HL2 [3-((2-(benzylthio)phenylimino)methyl)-2-hydroxy-5-methylbenzaldehyde] separately with Cu(OAc)2 center dot H2O afforded new Cu(II) complexes [Cu(L1)(OAc)] (1) and [Cu(L2)2] (2), respectively. These are characterized by microanalytical data and spectroscopic studies. UVvis spectra of the complexes show intense low-energy transitions approximate to 420nm which are ligand to metal charge transfer (LMCT) transitions. The single-crystal X-ray structures were determined for 1 and 2. Reactions of [Cu(L1)(OAc)] (1) with , SCN and show the replacement of weakly coordinated acetate yielding [Cu(L1)(N3)], [Cu(L1)(SCN)] and [Cu(L1)(NO2)], respectively. Unequivocal characterization of the substituted products has been done by single-crystal X-ray study of [Cu(L1)(N3)]. HL2 and its Cu(II) complex exhibited low-intensity emission bands at approximate to 575nm upon excitation at 375nm and at 420nm, respectively. Redox properties of the complexes were determined electrochemically. Density functional theory (DFT) computations have been carried out to explain the spectroscopic and redox properties of the complexes