Rhodium and platinum complexes as catalysts for the polymerization of phenylacetylene

In polymerization reactions of phenylacetylene three different types of polyphenylacetylene (PPA) were prepared by using Rh and Pt complexes as catalysts in different reaction conditions. Type I PPA is obtained with [Rh (COD) Chel] PF₆ complexes (COD = cis,cis-cycloocta 1,5-diene; chel = 2,2′-bipyridine, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline) in bulk, benzene methanol, while type II PPA is obtained with the same catalysts in p-dioxane and type III PPA in the presence of [Pt (? C?CPh)₂(PPh₃)₂] in bulk. Type I, II, and III PPA exhibit different IR and ¹H-NMR spectra, which have been compared with literature data. Correlations proposed by different Authors between spectral properties of PPA and chain structures are also discussed.     

Synthesis,characterization, DNA binding studies and in vitro cytotoxicity of platinum(II)-dihalogenido complexes containing bidentate chelating N-donor ligands

Platinum(II) complexes, [Pt(L_x)X₂] (1–6), where X = Br or I and L_x = 2,2′-bipyridine or 1,10-phenanthroline derivatives (5,5′-dimethyl-2,2′-bipyridine (5-Mebpy), 4,4′-dimethyl-2,2′-bipyridine (4-Mebpy), and 5-amino-1,10-phenanthroline (5-NH₂phen)) were prepared. The complexes were characterized by the elemental analysis, mass spectrometry, infrared, and multinuclear (¹H, ¹³C and ¹⁹⁵Pt) 1-D and 2-D NMR spectroscopies, and by single-crystal X-ray analysis of [Pt(4-Mebpy)I₂] (4). All the platinum(II) complexes (1–6) were evaluated for in vitro cytotoxicity against human cancer cell lines A2780 and A2780R, and against non-malignant MRC5 cell line. All the complexes were nontoxic up to the 50 μM concentration, although they were found to readily bind to calf-thymus DNA (CT-DNA), as determined by spectrophotometric titration (K_b ≈ 10⁷ M^?1) and ethidium bromide displacement assay.     

Synthesis,characterization, and DNA binding of ruthenium(II) complexes with 2-benzo[b] furan-2-yl-1H-imidazo[4,5f][1,10]phenanthroline as an intercalative ligand

DNA-binding properties of a number of ruthenium complexes with different polypyridine ligands are reported. The new polypyridine ligand BFIP (=2-benzo[b] furan-2-yl-1H-imidazo[4,5-f][1,10]phenanthroline) and its ruthenium complexes [Ru(bpy)₂BFIP]²⁺ (bpy = 2,2′-bipyridine), [Ru(dmb)₂BFIP]²⁺ (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Ru(phen)₂BFIP]²⁺ (phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, mass spectra, IR, UV-Vis, ¹H- and ¹³C-NMR, and cyclic voltammetry. The DNA binding of these complexes to calf-thymus DNA (CT-DNA) was investigated by spectrophotometric, fluorescence, and viscosity measurements. The results suggest that ruthenium(II) complexes bind to CT-DNA through intercalation. Photocleavage of pBR 322 DNA by these complexes was also studied, and [Ru(phen)₂BFIP]²⁺ was found to be a much better photocleavage agent than the other two complexes.     

Ruthenium(II) Complexes with Three Different Diimine Ligands

The synthesis of tri-heteroleptic complex of Ru(II) with diimine ligands is describe. Ten compounds [Ru(R₂bpy) (biq) (L)][PF₆]₂ (R = H, CH₃); L = 2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (Me₂bpy), 2,2′-bipyrimidine (bpm), 2,2′-biisoquinoline (biiq), 1,10-phenanthroline (phen), dipyrido[3,2-c:2′,3′-e]pyridazine (taphen), 2,2′-biquinoline (biq), 6,7-dihydrodipyrido[2,3-b:3,2-j][1,10]-phenanthroline (dinapy), 2-(2[pyridyl)quinoline (pq), 1-(2-pyrimidyl)pyrazole] (pzpm), 2,2′-biimidazole (H₂biim) are characterized by elemental analysis, electronic and ¹H-NMR spectroscopy. The relative photosustitution rates of biq in MeCN are given at three temperatures.     

Effect of the ancillary ligands on the binding of ruthenium(II) complexes [Ru(dmp)2(MCMIP)]2+ and [Ru(dmb)2(MCMIP)]2+ with DNA

Two polypyridine ruthenium(II) complexes, [Ru(dmp)₂(MCMIP)]²⁺ (1) (MCMIP = 2-(6-methyl-3-chromonyl)imidazo[4,5-f][1,10]-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline) and [Ru(dmb)₂(MCMIP)]²⁺ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), have been synthesized and characterized by elemental analysis, ES-MS and ¹H NMR. The DNA-binding behaviors of these complexes were investigated by electronic absorption titration, fluorescence spectroscopy, viscosity measurements and thermal denaturation. The results show that 1 and 2 effectively bind to CT-DNA; the DNA-binding affinities are closely related to the ancillary ligand.     

Chelate polypyridine ligand rearrangement in Au(III) complexes

The reaction of gold(III) neutral complexes AuBr(CN)₂(N–N) {N–N = 2,2′-bipyridine (bpy), 5,5′-dimethyl-2,2′-bipyridine (^Me2bpy), 1,10-phenanthroline (phen)} with a stoichiometric amount of K[AuCl₄] · 2H₂O in nitromethane at room temperature led to the formation of 1:1 electrolytes which were characterized by NMR and IR spectroscopy, conductivity measurements, elemental analyses and X-ray diffraction. Both the anions and the cations of these salts are singly charged square-planar Au(III) complexes and the cations have general formula [AuCl₂(N–N)]⁺. A hypothesis on the possible reaction mechanisms is presented to give an explanation for the formation of the reaction products.     

Synthesis,characterization, photocleavage,antimicrobial activity and DNA binding of [Co(bpy)2MHPIP]3+, [Co(dmb)2MHPIP]3+, and [Co(phen)2MHPIP]3+ complexes

4-Methyl-2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline) (MHPIP) and its complexes [Co(bpy)₂MHPIP]³⁺ (1) (bpy = 2,2′-bipyridine), [Co(dmb)₂MHPIP]³⁺ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)₂MHPIP]³⁺ (3) (phen = 1,10-phenanthroline) have been synthesized and characterized by UV/VIS, IR, EA, ¹H, ¹³C-NMR, and mass spectra. The binding of the three complexes with calf-thymus-DNA (CT-DNA) has been investigated by absorption and emission spectroscopy, DNA-melting techniques, viscosity measurements, and DNA cleavage assay. The spectroscopic data and viscosity results indicate that these complexes bind to CT-DNA via an intercalative mode. The complexes also promote photocleavage of plasmid pBR322 DNA and were screened for antimicrobial activity.     

Synthesis and magnetic studies of phthalato-bridged oxovanadium(IV) binuclear complexes

Six new μ-phthalato binuclear oxovanadium(IV) complexes, namely [(VO)₂(PHTH)-(L)₂]SO₄ (L denotes 2,2′-bipyridine (bpy); 1,10-phenanthroline (phen); 4,4′-dimethyl-2,2′-bipyridine (Me₂ bpy); 5-nitro-1,10-phenanthroline (NO₂-phen); 5-chloro-1,10-phenanthroline (Cl-phen) and 5-methyl-1,10-phenanthroline (CH₃-phen), where PHTH is the phthalate dianion), have been synthesized and characterized by elemental analyses, IR, electronic spectra, magnetic moments at room temperature and molar conductivity measurements. The temperature dependence of the magnetic susceptibility of complexes [(VO)₂(PHTH)(phen)₂]SO₄ (1) and [(VO)₂(PHTH)(CH₃-phen)₂]SO₄ (2) was measured in 4—300 K range and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, ?=?2J?₁·?₂, giving the exchange integrals J=?12.8 cm^?1 for 1 and J=?7.9 cm^?l for 2. This indicates an antiferromagnetic spin-exchange interaction between the metal ions within each molecule.     

2+1 Rhenium Tricarbonyl Complexes with N,N′-Bidentate Ligands and Ethyl Isocyanoacetate: Synthesis,Structure, and Properties

Russian Journal of General Chemistry - 2+1 tricarbonyl complexes [Re(CO)3(N^N)CNCH2COOEt]X, where N^N = 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) and X = Cl– or ClO4–,...     

Conversion of Light into Electricity with Trinuclear Ruthenium Complexes Adsorbed on Textured TiO2 Films

A series of CN-bridged trinuclear Ru complexes of the general structure [RuL₂(μ-(CN)Ru(CN)L₂′)₂] where L is 2,2′-bipyridine-4,4′-dicarboxylic acid and L′ is 2,2′-bipyridine ( 1 )2,2′-bipyridine-4,4′-dicarboxylic acid ( 2 ), 4,4′-dimethyl-2,2′-bipyridine ( 3 ), 4,4′-diphenyl-2,2′-bipyridine ( 4 ), 1,10-phenanthroline ( 5 ), and bathophenanthrolinedisulfonic acid ( 6 ) have been synthesized, and their spectral and electrochemical properties investigated. The two carboxylic functions on the 2,2′-bipyridine ligand L serve as interlocking groups through which the dye is attached at the surface of TiO₂ films having a specific surface texture. The role of these interlocking groups is to provide strong electronic coupling between the π* orbital of the 2,2′-bipyridine and the 3d-wave-function manifold of the conduction band of the TiO₂, allowing the charge injection to proceed at quantum yields close to 100 %. The charge injection and recombination dynamics have been studied with colloidal TiO₂, using laser photolysis technique in conjunction with time-resolved optical spectroscopy. Photocurrent action spectra obtained from photo-electrochemical experiments with these trinuclear complexes cover a very broad range in the visible, making them attractive candidates for solar light harvesting. Monochromatic incident photon-to-current conversion efficiencies are strikingly high exceeding 80% in some cases. Performance characteristics of regenerative cells operating with these trinuclear complexes and ethanolic triiodide/iodide redox electrolyte have been investigated. Optimal results were obtained with complex 1 which gave a fill factor of 75 % and a power conversion efficiency of 11.3% at 520 nm.     

Preparations and properties of vanadium(III) complexes of bidentate and terdentate nitrogen-donor ligands

Summary Vanadium(III) chloride reacts with 1,10-phenanthroline and 2,2-bipyridyl, and with substituted derivatives of each ligand (B), in ethanol or in acetonitrile as solvent (L), to yield two different series of complexes. These are (a) the neutral species VCl₃BL, where B = 1,10-phenanthroline, 5-chloro-1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 2,2-bipyridyl, 4,4-dimethyl-2,2-bipyridyl, L = ethanol. The complexes in which B = 1,10-phenanthroline or 2,2-bipyridyl were also obtained with L = acetonitrile, (b) [VCl₂B₂]⁺[VCl₄B]^– where B is the same series of ligands listed above. Vanadium(III) chloride yields VCl₃ (terpy) with 2,2,2 -terpyridyl. All the complexes have been characterised by elemental analyses, conductance measurements, electronic- and i.r. spectral measurements, and by their temperature-range (297–77 K) magnetic moments; ring substituents have little influence on any chemical or physical properties of these complexes.     

Kinetics of the aquation of cis-chlorocyanobis(2,2′-bipyridine)cobalt(III) and cis-chlorocyanobis(1,10-phenanthroline)cobalt(III) cations

We have studied the kinetics of aquation of cis-chlorocyanobis(2,2′-bipyridine)Co(III), and cis-chlorocyanobis(1,10-phenanthroline)Co(III) cations, and determined activation parameters, in order to compare the labilities of these cations with the lability of the analogous compounds containing ethylenediamine and other non-participating ligands such as Cl^? and NO₂^?.     

Crystal structures and antibacterial properties of Cu(II) complexes containing an unsymmetrical N2O Schiff base ligand and bidentate N-donor heterocyclic co-ligands

Abstract

Three new Cu(II) Schiff base complexes with bidentate N-donor heterocyclic co-ligands, 2,2'-bipyridine (1), 1,10-phenanthroline (2), and 2,9-dimethyl-1,10-phenanthroline (3), were synthesized and characterized by FT-IR and UV-vis spectroscopy. Molecular structures of [C₂₀H₂₁CuN₄O](ClO₄) (1) and [C₂₄H₂₅CuN₄O](ClO₄) (3) were characterized by single-crystal X-ray crystallography. The Schiff base ligand is an N₂O-type ligand, which is the mono-condensed form of the reaction between 1,3-propanediamine and salicylaldehyde. The antibacterial activities of these complexes were investigated against one gram positive and four gram negative bacteria. Considerable antibacterial activity was obtained against both gram type bacteria. Complexes 2 and 3 with 1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline, respectively, showed better antibacterial activity compared to 1 which has the 2,2'-bipyridine co-ligand.     

Substitution reactions of trans-[PdXPh(SbPh3)2J (X=Cl or Br) with nitrogen,phosphines and arsenic donor ligands. Crystal structures of trans-[PdClPh(PPh3)2], [PdClPh(bipy)], [PdClPh(dppm)]2, and [PdBrPh(dppm)]2

Exchange reactions of trans-[PdXPh(SbPh₃)₂] (1) (X=Cl or Br) with ligands L in refluxing dichloromethane give the palladium phenyl complexes [PdXPhL₂] (X=Cl, L=PPh₃, AsPh₃, L₂=2,2′-bipyridine (bipy), 4,4′-dimethyl-2,2′-bipyridine (dmbipy), 1,10-phenanthroline (phen); X=Br, L=PPh₃, L₂=bipy). Treatment of the complexes with bis(diphenylphosphino)methane (dppm) in refluxing dichloromethane gives [PdXPh(dppm]₂. These complexes have been characterised by microanalysis, IR and ¹H NMR spectroscopic data together with single crystal X-ray determinations of the phenyl palladium complexes, trans-[PdClPh(PPh₃)₂], [PdClPh(bipy)], [PdClPh(dppm)]₂, and [PdBrPh(dppm)]₂.     

DNA interactions of ruthenium(II) complexes with a polypyridyl ligand: 2-(2, 5-dimethoxyphenyl)-1<Emphasis Type="Italic">H</Emphasis>-imidazo[4,5-<Emphasis Type="Italic">f</Emphasis>]1,10-phenanthroline

This article describes the synthesis of a polypyridyl ligand, namely 2-(2, 5-dimethoxyphenyl)-1H-imidazo[4,5-f]1,10-phenanthroline (DMPIP) and its Ru(II) complexes, namely [Ru(bipy)₂DMPIP]²⁺ (1), [Ru(dmb)₂DMPIP]²⁺ (2) and [Ru(phen)₂DMPIP]²⁺ (3) ((bipy = 2,2′-bipyridine, dmb = 4,4′-dimethyl-2,2′-bipyridine, phen = 1,10-phenanthroline). The complexes were characterized by elemental analysis, plus IR, ¹H-NMR and ¹³C [¹H]-NMR spectra. The interactions of the complexes with calf thymus DNA were investigated. The results indicate that the three complexes can intercalate into DNA. Under irradiation at 365 nm, all three complexes promote the photocleavage of plasmid pBR 322 DNA. Inhibitor studies suggest that singlet oxygen plays a significant role in the cleavage mechanism for the complexes.     

&“RuNO&”6 and &“RhNO&”6 compexes with 2,2′-bipyridine and 1,10-phenanthroline

The reactions of nitrosyl halides NOX (X = Cl, Br or Br₃) and N₂O₃ with RuCl₃(H₂O)₃ and RhCl₃(H₂O)₃ in the presence of 2,2′-bipyridine and 1,10-phenanthroline results in the formation of neutral nitrosyl complexes of types Ru(NO)X₃(L-L) and Rh(NO)X₂(L-L) (L-L = 2,2′-bipyridine or 1,10-phenanthroline).     

Synthesis and spectral studies on mixed ligand complexes of Cd(II) dithiocarbamates with nitrogen donors: single crystal X-ray structure of bis (4-methylpiperidinecarbodithioato-S,S′)(1,10-phenanthroline)cadmium(II)

The current article describes the synthesis and characterization of the following adducts: [Cd(2-mpipdtc)₂(1,10-phen)], [Cd(2-mpipdtc)₂(bipy)], [Cd(4-mpipdtc)₂(1,10-phen)], [Cd(4-mpipdtc)₂(bipy)] (where 2-mpipdtc^? = 2-methylpiperidinecarbodithioate anion, 4-mpipdtc^? = 4-methylpiperidinecarbodithioate anion, 1,10-phen = 1,10-phenanthroline and bipy = 2,2′-bipyridine). A single crystal X-ray structural analysis was carried out for [Cd(4-mpipdtc)₂(1,10-phen)]. IR spectra of the complexes show the contribution of the thioureide form to the structures. Reduction in ν_C–N(thioureide) for the mixed ligand complexes is attributed to the change in coordination number from four to six and the steric effect exerted by 1,10-phenanthroline or 2,2′-bipyridine. Deshielding of the protons adjacent to nitrogen in the ¹H NMR spectra is attributed to drift of electrons from the nitrogen of NR₂, forcing electron density towards sulfur via the thioureide π-system. Single crystal X-ray structural analysis of [Cd(4-mpipdtc)₂(1,10-phen)] showed that the cadmium is in a distorted octahedral environment with a CdS₄N₂ chromophore. The presence of 1,10-phenanthroline in the coordination sphere of Cd(dtc)₂ increases the Cd–S distances and decreases the S–Cd–S angles. VBS analysis supports the determined structure.     

Allyl rhodium(III) complexes containing heterocyclic nitrogen ligands

Summary A series of hexacoordinated Rh^III complexes of general formula trans-[RhCl₂(allyl)(N-N)] (allyl = C₃H₅ or C₄H₇; N- = 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,2-bipyridine or 4,4-dimethyl-2,2-bipyridine) have been synthesized and characterized by spectroscopic methods. The complexes have an octahedral geometry with the Cl ligands coordinated in the trans positions. The catalytic activity of [RhCl₂(C₄H₇)(phen)] with respect to hydrogenation of alkenes has been investigated.     

Mixed-ligand complexes of copper(I) with diimines and phosphines: Effective catalysts for the coupling of phenylacetylene with halobenzene

New copper(I) mixed-ligand complexes 1–4 of the formula Cu(N–N)PR₃X, where N–N = 1,10-phenanthroline (phen), 2,2′-bipyridine (bpy), 5,5′-dimethyl-2,2′-bipyridine (5,5′dimbpy) and PR₃ = tricyclohexylphosphine, tris(2-cyanoethyl)phosphine and isopropyldiphenylphosphine, have been synthesized. The complexes were characterized by EA, IR, NMR and single crystal X-ray diffraction. The solution fluorescence emission spectra were measured. The single crystal X-ray analysis showed that the copper(I) ion is four-coordinate with a distorted tetrahedral geometry. The complexes catalyze the formation of diphenylacetylene from the coupling of halobenzene with phenylacetylene. The complex Cu(5,5′-dimethylbpy)P{(cyhexyl)₃}I showed the highest catalytic activity. At room temperature all four complexes exhibit, in dichloromethane, emission maxima in the 329–344 nm range, corresponding to intra-ligand excited states.     

Studies on reactions of some ruthenium sulfoxide bipyridyl complexes with 1,4-bis(salicylidene)phenylenediamine ligand used as spacer

A dinucleating spacer 1,4-bis(salicylidene)phenylenediamine (SALPHEN) derived from 1,4-phenylenediamine and salicylaldehyde has been synthesized and characterized. The ruthenium(II) sulfoxide derivative of 2,2′-bipyridine or 1,10-phenanthroline on reaction with this ligand resulted in the formation of eight dinuclear complexes, which were characterized by elemental analyses, conductivity measurements, magnetic susceptibility, FT-IR, fast atom bombardment-mass spectra, electronic spectroscopy, ¹H-NMR, ¹³C{¹H}-NMR, and ²D-NMR spectra (HETCOR). The prepared complexes have two different formulations, [{trans-RuCl₂(so)(N–N′)}₂(μ-SALPHEN)] and [{cis-RuCl₂(so)(N–N′)}₂(μ-SALPHEN)], where so?=?dimethyl sulfoxide (DMSO)/tetramethylene sulfoxide (TMSO), N–N′?=?2,2′-bipyridine/1,10-phenanthroline, and SALPHEN?=?1,4-bis(salicylidene)phenylenediamine. Two moles of ruthenium sulfoxide bipyridine precursor were coordinated to the bidentate SALPHEN through nitrogen. All the complexes possess antibacterial activity against Escherichia coli in comparison to Chloramphenicol.