Ruthenium(II) carbonyl complexes with tridentate Schiff bases and their antibacterial activity

The products obtained by reacting ruthenium (II) complexes [RuHCl(CO)(PPh₃)₂(B)] [B = PPh₃, pyridine (py) or piperidine (pip)] with tridentate Schiff base ligands derived by condensing salicylaldehyde or o-vanillin with o-aminophenol and o-aminothiophenol, have been characterised by analytical, i.r., electronic, ¹H-n.m.r. and ³¹P-n.m.r. spectral studies and formulated as [Ru(L)(CO)(PPh₃)(B)] (L = bifunctional tridentate Schiff base anion, B = PPh₃, py or pip). An octahedral structure has been tentatively proposed for the new complexes. Some have been tested for the in vitro growth inhibitory activity against bacteria Escherichia coli, Bacillus sp. and Pseudomonas sp.     

Spectroscopic characterization and electrochemical studies of ruthenium(II) carbonyl complexes containing bidentate Schiff bases and triphenylphosphine or a nitrogen heterocycle

Reactions of ruthenium(II) carbonyl complexes of the type [RuHCl(CO)(PPh₃)₂(B)] [B?=?PPh₃, pyridine (py), piperidine (pip) or morpholine (mor)] with bidentate Schiff base ligands derived from the condensation of 2-hydroxy-1-naphthaldehyde with aniline, o-, m- or p-toluidine in a 1?:?1 mol ratio in benzene resulted in the formation of complexes formulated as [RuCl(CO)(L)(PPh₃)(B)] [L?=?bidentate Schiff base anion, B?=?PPh₃, py, pip, mor]. The complexes were characterized by analyses, IR, electronic and ¹H NMR spectroscopy, and cyclic voltammetric studies. In all cases, the Schiff bases replace one molecule of phosphine and a hydride ion from the starting complexes, indicating that Ru–N bonds in the complexes containing heterocyclic nitrogenous bases are stronger than the Ru–P bond to PPh₃. Octahedral geometry is proposed for the complexes.     

Catalytic and antimicrobial activities of new ruthenium(II) unsymmetrical Schiff base complexes

Hexa-coordinated ruthenium(II) complexes of the type [Ru(CO)(PPh₃)(Z)(L)] [Z = PPh₃, pyridine (py) or piperidine (pip); L = anion of the Schiff base] have been prepared by reacting [RuHCl(CO)(PPh₃)₂(Z)] with tridentate Schiff bases derived by condensing anthranilic acid with acetylacetone, salicylaldehyde, o-vanillin and o-hydroxyacetophenone. The complexes were characterised by analytical and spectral (i.r., electronic, ¹H- and ³¹P-n.m.r.) data, and were found to be effective catalysts for oxidising primary alcohols to aldehydes in the presence of N-methylmorpholine-N-oxide (NMO) as co-oxidant. The Schiff bases and their ruthenium(II) complexes show growth inhibitory activity against pathogenic fungi Aspergillus flavus, Fusarium oxysporium and Rhizoctonia solani.     

Ruthenium(II) complexes containing triphenylphosphine/triphenylarsine and bidentate Schiff bases derived from 2-hydroxy-1-naphthaldehyde and primary amines

The synthesis and characterisation of some new hexa-coordinated Schiff base complexes of the type [RuCl(CO)(EPh₃)(B)(L)] (E = P or As; B = PPh₃ or AsPh₃ or py or pip; L = anion of the Schiff bases derived from 2-hydroxy-1-naphthaldehyde and aniline, 4-chloroaniline or 2-methylaniline) are reported. I.r., electronic, ¹H-n.m.r, ³¹P-n.m.r. spectra, catalytic activity and antibacterial activity of the complexes are discussed. An octahedral structure has been tentatively proposed for all the complexes.     

Synthesis,characterization and catalytic studies of ruthenium(II) Schiff base complexes

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 the condensation of salicyloyl hydrazide with acetone, ethyl methyl ketone and salicylaldehyde have been synthesised by the reaction of equimolar amounts of [RuHCl(CO)(EPh₃)₂(B)] and Schiff bases in benzene. The resulting complexes have been characterized by analytical and spectral (i.r., electronic, n.m.r.) data. The arrangements of Ph₃P groups around the Ru metal was determined from ³¹P-n.m.r. spectra. An octahedral structure has been assigned to all the new complexes. All the complexes exhibit catalytic activity for the oxidation of benzyl alcohol and cyclohexanol in the presence of N-methylmorpholine-N-oxide as co-oxidant.     

Ruthenium(II) complexes containing bidentate Schiff bases and triphenylphosphine or triphenylarsine

Reactions of ruthenium(II) complexes [RuHX(CO)(EPh₃)₂(B)] (X = H or Cl; B = EPh₃, pyridine (py) or piperidine (pip); E = P or As) with bidentate Schiff base ligands derived by condensingo- hydroxyacetophenone with aniline,o- orp-methylaniline have been carried out. The products were characterized by analytical, IR, electronic and¹H-NMR spectral studies and are formulated as [Ru(X)(CO) (L)(EPh₃)(B)] (L = Schiff base anion; X = H or Cl; B = EPh₃, py or pip; E = P or As). An octahedral structure has been tentatively proposed for the new complexes. The new complexes were tested for their catalytic activities in the oxidation of benzyl alcohol to benzaldehyde.     

Synthesis,characterization and biocidal studies of ruthenium(II) carbonyl complexes containing tetradentate Schiff bases

Stable ruthenium(II) complexes of Schiff bases have been prepared by reacting [RuHCl(CO)(PPh₃)₂(B)] (B = PPh₃, pyridine or piperidine) with bis(o-vanillin)ethylenediimine (valen), bis(o-vanillin)propylene-diimine (valpn), bis(o-vanillin)tetramethylenediimine (valtn), bis(o-vanillin)o-phenylenediimine (valphn), bis(salicylaldehyde)tetramethylenediimine (saltn) and bis(salicylaldehyde)o-phenylenediimine (salphn). These complexes have been characterised by elemental analyses, i.r., electronic, ¹H- and ³¹P{¹H}-n.m.r. spectral studies. In all the above reactions, the Schiff bases replace two molecules of Ph₃P, a hydride and a halide ion from the starting complexes, indicating that the Ru–N bonds present in the complexes containing heterocyclic nitrogen bases are stronger than the Ru–P bond to Ph₃P. The new complexes of the general formula [Ru(CO)(B)(L)] (B = PPh₃, py or pip; L = tetradentate Schiff bases) have been assigned an octahedral structure. Some of the Schiff bases and the new complexes have been tested against the pathogenic fungus Fusarium sp.     

Antibacterial activity of ruthenium(II) carbonyl complexes containing tetradentate Schiff bases

Several new hexa-coordinated ruthenium(II) complexes of the type [Ru(CO)(LL)(B)] (where, LL = anthacac, anthdibm, 2-amtpacac or 2-amtpdibm; B = PPh₃ or py or pip or morph) have been prepared by reacting [RuHCl(CO)(PPh₃)₃] or [RuHCl(CO)(PPh₃)₂(B)] with tetradentate Schiff bases such as bis(anthranilic acid)acetylacetimine (H₂-anthacac), bis(anthranilic acid) dibenzoylmethimine (H₂-anthdibm), bis(2-aminothiophenol) acetylacetimine (H₂-2-amptacac) or bis(2-aminothiophenol) dibenzoylmethimine (H₂-2-amtpdibm). The complexes have been characterised by elemental analyses and spectral (i.r., electronic spectra, ¹H- and ³¹P-n.m.r.) data. An octahedral structure has been tentatively proposed for the complexes, which were also tested for their antibacterial properties.     

Ruthenium(II) carbonyl complexes containing tridentate Schiff bases

New ruthenium(II) complexes, [Ru(CO)(B)(LL)(PPh₃)] (where, LL = tridentate Schiff bases; B = PPh₃, pyridine, piperidine or morpholine) have been prepared by reacting [RuHCl(CO)(PPh₃)₃] or [RuHCl(CO)(PPh₃)₂(B)] with Schiff bases containing donor groups (O, N, X) viz., salicylaldehyde thiosemicarbazone (X = S), salicylaldehyde semicarbazone (X = O), o-hydroxyacetophenone thiosemicarbazone (X = S) and o-hydroxyacetophenone semicarbazone (X = O). The new complexes were characterised by elemental analysis, spectral (i.r., ¹H- and ³¹P-n.m.r.), data.     

Mixed ligand complexes of ruthenium(II) containing α,β-unsaturated-β-ketoaminesand their antibacterial activity

Hexacoordinated Ru^II complexes of the [RuX(CO)(PPh₃)(B)(LL)] type [X = Cl; B = PPh₃, pyridine (py), piperidine (pip) or morpholine (morph); LL = ,-unsaturated--ketoaminate] have been synthesised by reacting [RuHCl(CO)(PPh₃)(B)] (B = PPh₃, py, pip or morph) with the appropriate -ketoamine in a 1:1 molar ratio. The replacement of hydride ion and the triphenylphosphine group by a bidentate chelating ligand from the starting compounds occurs. The complexes were characterised by elemental analyses and spectral (i.r., electronic, ¹H- and ³¹P-n.m.r.) data. Antibacterial activity were also tested for in these new complexes.     

Ruthenium(II) carbonyl complexes containing tetradentate Schiffbases

Ruthenium(II) carbonyl complexes of general formula [Ru(CO)(B)(L)] [where B = PPh3, pyridine (py), piperidine (pip); L = the dianionic tetradentate Schiff bases derived from the condensation of acetylacetone or benzoylacetone with ethylenediamine, propylenediamine or trimethylenediamine] have been synthesised by reacting [RuHCl(CO)(PPh3)2(B)] (B = PPh3, py or pip) with bis(acetylacetone)ethylenediimine, bis(acetylacetone)propylenediimine, bis(acetylacetone)trimethylenedi- imine, bis(benzoylacetone)ethylenediimine, bis(benzoylacetone)propylenediimine or bis(benzoylacetone)trimethylenediimine. The complexes were characterised onthe basis of elemental analyses, i.r., electronic and 1H- and 31P{1H}-n.m.r. spectral studies. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis, structural characterization and electrochemical studies of nickel(II), copper(II) and cobalt(III) complexes of some ONS donor ligands derived from thiosemicarbazide and S-alkyl/aryl dithiocarbazates

Four tridentate ONS ligands, namely 2-hydroxyacetophenonethiosemicarbazone (H₂L¹), the 2-hydroxyacetophenone Schiff base of S-methyldithiocarbazate (H₂L²), the 2-hydroxy-5-nitrobenzaldehyde Schiff base of S-methyldithiocarbazate (H₂L³), and the 2-hydroxy-5-nitrobenzaldehyde Schiff base of S-benzyldithiocarbazate (H₂L⁴), and their complexes of general formula [Ni(HL¹)₂], [ML] (M?=?Ni^II or Cu^II; L?=?L¹, L², L³ and L⁴), [Co(HL)(L); L?=?L¹, L², L³ and L⁴] and [ML(B)] (M?=?Ni^II or Cu^II; L?=?L² and L⁴; B?=?py, PPh₃) have been prepared and characterized by physico-chemical techniques. Spectroscopic evidence indicates that the Schiff bases behave as ONS tridentate chelating agents. X-ray crystallographic structure determination of [NiL²(PPh₃)] and [CuL⁴(py)] indicates that these complexes have an approximately square-planar structure with the Schiff bases acting as dinegatively charged ONS tridentate ligands coordinating via the phenoxide oxygen, azomethine nitrogen and thiolate sulfur atoms. The electrochemical properties of the complexes have been studied by cyclic voltammetry.     

Synthesis,crystal structure and catalytic activity of ruthenium(II) carbonyl complexes containing ONO and ONS donor ligands

Diamagnetic ruthenium(II) complexes of the type [Ru(L)(CO)(B)(EPh₃)] [where E = As, B = AsPh₃; E = P, B = PPh₃, py (or) pip and L = dibasic tridentate ligands dehydroacetic acid semicarbazone (abbreviated as dhasc) or dehydroacetic acid phenyl thiosemicarbazone (abbreviated as dhaptsc)] were synthesized from the reaction of [RuHCl(CO)(B)(EPh₃)₂] (where E = As, B = AsPh₃; E = P, B = PPh₃, py (or) pip) with different tridentate chelating ligands derived from dehydroacetic acid with semicarbazide or phenylthiosemicarbazide. All the complexes have been characterized by elemental analysis, FT-IR, UV–Vis and ¹H NMR spectral methods. The coordination mode of the ligands and the geometry of the complexes were confirmed by single crystal X-ray crystallography of one of the complexes [Ru(dhaptsc)(CO)(PPh₃)₂] (5). All the complexes are redox active and are monitored by cyclic voltammetric technique. Further, the catalytic efficiency of one of the ruthenium complexes (5) was determined in the case of oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide.     

Ruthenium(II) unsymmetrical N2O2 tetradentate Schiff-base complexes: synthesis,characterization, and catalytic studies

A series of six-coordinate ruthenium(II) complexes [Ru(CO)(L ^x )(B)] (B = PPh₃, AsPh₃ or Py; L ^x = unsymmetrical tetradentate Schiff base, x = 5–8; L⁵= salen-2-hyna, L⁶= Cl-salen-2-hyna, L⁷= valen-2-hyna, L⁸= o-hyac-2-hyna) have been prepared by reacting [RuHCl(CO)(EPh₃)₂(B)] (E = P or As) with unsymmetrical Schiff bases in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (infrared, electronic, ¹H, ³¹P, and ¹³C NMR) data. An octahedral structure has been assigned for all the complexes. The new complexes are efficient catalysts for the transfer hydrogenation of ketones and also exhibit catalytic activity for the carbon–carbon coupling reactions.     

Synthesis,characterization and catalytic studies of ruthenium(II) chalconate complexes

Stable ruthenium(II) carbonyl complexes of the type [RuCl(CO)(EPh₃)(B)(L)] (E = P or As; B = PPh₃, AsPh₃ or Py; L = 2′‐hydroxychalcones) were synthesized from the reaction of [RuHCl(CO)(EPh₃)₂(B)] (E = P or As; B = PPh₃, AsPh₃ or Py) with 2′‐hydroxychalcones in benzene under reflux. The new complexes were characterized by analytical and spectroscopic (IR, electronic ¹H, ³¹P and ¹³C NMR) data. They were assigned an octahedral structure. The complexes exhibited catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N‐methylmorpholine‐N‐oxide (NMO) as co‐oxidant and were also found to be efficient transfer hydrogenation catalysts. Copyright © 2008 John Wiley & Sons, Ltd.     

Novel bidentate ruthenium(III) Schiff base complexes: synthetic,spectral, electrochemical,catalytic and antimicrobial studies

Ru^III complexes of the type [RuX(L)₂(E)] (X = Cl or Br; L = novel bidentate Schiff base ligand; E = PPh₃ or AsPh₃) have been prepared by reacting [RuX₃(E)₃] or [RuBr₃(PPh₃)₂(MeOH)] with two novel bidentate Schiff base ligands derived from 4-(1-methyl-1-mesitylcyclobutane-3-yl)-2-aminothiazole, in a 1:2 molar ratio in benzene, and characterised by analytical, spectral (i.r., electronic, ¹H-, ¹³C- n.m.r., and e.p.r.) and electrochemical data. An octahedral structure has been tentatively proposed for all the new complexes. The thermal properties of the ligands and their complexes have been studied by t.g.a. The new Ru^III complexes are effective catalysts for the oxidation of alcohols to carbonyl compounds but are unable to oxidise alkenes in the presence of N-methylmorpholine-N-oxide (NMO) as co-oxidant. The antimicrobial activity of the ligands and complexes have also been tested against six microorganisms.     

Studies on ruthenium(II) Schiff base complexes as catalysts for transfer hydrogenation reactions

The reactions of [RuHCl(CO)(B)(EPh₃)₂] (B = EPh₃ or Py; E = P or As) and Schiff bases in 1:1 molar ratio led to the formation of [RuCl(CO)(EPh₃)(B)(L)] (E = P or As; B = PPh₃, AsPh₃ or Py; L = Schiff base ligand). The new complexes have been characterized by analytical and spectroscopic (IR, electronic and ¹H NMR) data. They have been assigned an octahedral structure. The new complexes were found to catalyse the transfer hydrogenation of ketones.     

Synthesis, spectral characterization and catalytic studies of new ruthenium(II) chalcone thiosemicarbazone complexes

A series of new hexa-coordinated ruthenium(II) complexes of the type [Ru(CO)(EPh₃)(B)(L)] (E = P or As; B = PPh₃, AsPh₃ or Py; L = chalcone thiosemicarbazone) have been prepared by reacting [RuHCl(CO)(EPh₃)₂(B)] (E = P or As; B = PPh₃, AsPh₃ or Py) with chalcone thiosemicarbazones in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (IR, UV-vis, ¹H, ³¹P and ¹³C NMR) methods. On the basis of data obtained, an octahedral structure was assigned for all of the complexes. The chalcone thiosemicarbazones behave as dianionic tridentate O, N, S donors and coordinate to ruthenium via the phenolic oxygen of chalcone, the imine nitrogen of thiosemicarbazone and thienol sulfur. The new complexes exhibit catalytic activity for the oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones and they were also found to be efficient catalysts for the transfer hydrogenation of carbonyl compounds.     

Ruthenium(II) complexes of hybrid 8‐hydroxyquinoline–thiosemicarbazone ligands: synthesis,characterization and catalytic applications

A series of new hexa‐coordinated ruthenium(II) hydroxyquinoline–thiosemicarbazone complexes of the type [Ru(CO)(EPh₃)(B)(L)] (E = P or As; B = PPh₃, AsPh₃ or Py; L = hydroxyquinoline–thiosemicarbazone) were synthesized by reacting ruthenium precursor complexes [RuHCl(CO)(EPh₃)₂(B)] (E = P or As; B = PPh₃, AsPh₃ or Py) with hydroxyquinoline–thiosemicarbazone ligands in ethanol. The new complexes were characterized by analytical and spectroscopic (FT‐IR, UV–visible, NMR (¹H, ¹³C and ³¹P) and fast atom bombardment (FAB)–mass spectrometric methods. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The new complexes showed good catalytic activity for the conversion of aldehydes to amides in the presence of hydroxylamine hydrochloride–sodium bicarbonate and for the oxidation of alkanes into their corresponding alcohols and ketones in the presence of m‐chloroperbenzoic acid. The complexes also catalyzed the N‐alkylation of benzylamine in the presence of KOtBu in alcohol medium. Copyright © 2013 John Wiley & Sons, Ltd.     

Dinuclear group VIB metal carbonyl complexes bridged by bis(diphenylphosphino)alkanes

Reactions of the intermediate W(CO)₅THF, generated photochemically from W(CO)₆ in THF, with Ph₂P(CH₂) _n PPh₂ [ = PP; n = 2 (dppe), 4 (dppb), 6 (dpph), 10 (dppd)] at room temperature in THF solutions gave exclusively bimetallic complexes of the (CO)₅WPPW(CO)₅ type. In addition, complexes bridged by diphosphine ligands of the (CO)₄(pip)MPPM(pip)(CO)₄ type (pip = piperidine; M = Mo, W) were prepared by stirring the (CO)₄M(pip)₂ complexes with bis(diphenylphosphino)alkanes in CH₂Cl₂ solution at ambient temperatures. These new bis(diphenylphosphino)alkane-bridged complexes were characterized by i.r., ¹H- and ³¹P-n.m.r. spectroscopies, as well as by elemental analysis.