Synthesis and characterization of ruthenium complexes immobilized on poly(4-vinylpyridine)

The [Ru(NH₃)₅(H₂O)]²⁺ andtrans-[Ru(NH₃)₄SO₂(H₂O)]²⁺ complexes ions were immobilized on poly(4-vinylpyridine) (4-PVP) through reactions in aqueous solutions. The stability of the imobilized complexes was checked in aqueous solution in the pH 2.0–8.0 range. The number of pyridinic nitrogens in the polymer 4-PVP is 2.80±0.05 mmol/g according to nitrogen elemental analysis. Potentiometric titration experiments showed that the accessible nitrogen, in aqueous medium, was 0.94±0.02 mmol/g with a pK _a value of 7.4±0.2. In addition, ruthenium and sulfate analysis has demonstrated that about 15% of the accessible nitrogen sites are able to coordinate to the metal centers. The characterization of the immobilized complexes was made through diffuse electronic and infrared spectroscopies and differential pulse and cyclic voltammetries.     

Synthesis,X-ray structure,density functional theory (DFT) study on electronic and optical properties of a novel 2D-polyoxovanadate anionic compound

A novel two-dimensional (2D) polyoxovanadate compound KV₃O₈ (1) has been synthesized and characterized crystallographically. The 2D anionic frameworks are built up from distorted VO₆ octahedrons and VO₅ square pyramids which are linked to one another via μ₁-oxo, μ₂-oxo and μ₃-oxo atoms. The energy band structure, density of states (DOS), dielectric constant, refractive index and chemical bonds have been investigated by DFT method. The calculated results indicate that 1 is a semi-conductor (band gap 2.1 eV). The character of the VO interactions is mainly covalent, while that of the K–O interactions is mainly ionic. The top of valence bands and the bottom of conduction bands are mostly built upon O 2p states mixed with V 3d states, and V 3d states mixed with O 2p states, respectively, via covalent P–O interactions. The nature of electronic absorption peak is assigned to be O(2p) → V(3d) charge transfer transition.     

Synthesis, characterization and crystal structure of a novel thiocyanate–ruthenium(II) complex

The cis-[Ru(dppb)(Me-bipy)(NCS)₂], dppb = 1,4-bis (diphenylphosphino)butane, Me-bipy = 4,4′-dimethyl-2,2′-bipyridine, and NCS = thiocyanate, was synthesized and characterized by spectroscopic and electrochemical techniques and its structure was determined by crystal X-ray analysis. The crystal structure reveals that the coordination geometry around the Ru(II) center is distorted octahedron where two molecules of thiocyanate are bonded to the ruthenium through nitrogen atom in cis orientation. The half-wave formal potential value E_1/2 = 0.8 V (versus Ag/AgCl) observed is considerable higher than that for the cis-[RuCl₂(dppb)(Me-bipy)] complex, E_1/2 = 0.6 V (versus Ag/AgCl), well illustrating the strong π-acceptor effect the NCS ligand toward the backbonding interaction with the Ru(II) metal center. The MLCT absorption bands of the thiocyanate complex present a higher molar absorptivity (about 12%) compared with the cis-[RuCl₂(dppb)(Me-bipy)] complex, in the same experimental conditions. These properties make the complex potentially promising for the photosensitization process.     

Synthesis,characterization and molecular structure of Re(III) complexes containing 2-benzoylpyridine

The paper presents a combined experimental and computational study of Re(III) complexes containing 2-benzoylpyridine (bopy). Two novel complexes [ReX₃(bopy)(PPh₃)] (X = Cl, Br) have been obtained in the reactions of [ReX₃(MeCN)(PPh₃)₂] with 2-benzoylpyridine in dichloromethane and have been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structure of [ReCl₃(bopy)(PPh₃)] has been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of [ReCl₃(bopy)(PPh₃)] have been calculated with the time-dependent DFT method and the UV–Vis spectrum has been discussed on this basis.     

Electropolymerization and characterization of terpyridinyl iron (II) and ruthenium (II) complexes

Electroactive 2,2′: 6,2″-terpyridinyl ligands ( 3, 5, 6 ) and their iron(II) ( 7a–9a ) and ruthenium(II) complexes ( 7b–9b ) were synthesized. Bis[3-(aminophenyl)-2,2′ :6,2″-terpyridinyl]metal(II) complexes ( 7a, 7b ) and bis[2-(hydroxyphenyl)-2,2′ :6,2″-terpyridinyl]metal(II) complexes ( 8a, 8b ) were electropolymerized on to the surface of Pt or In-SnO₂ (ITO) electrodes in acetonitrile containing Bu₄NCIO₄ by scanning the potential between O and + 1.6V (for 7a and 7b ), and ?0.8 and +1.6V (for 8a and 8b ) versus saturated calomel electrode. The electrodes obtained by electropolymerization exhibited reversible electrochromism based on Fe(II)/Fe(III) or Ru(II)/Ru(III) redox couple. Photoresponses to visible light were found in the modified electrode obtained by electropolymerization of ruthenium complex 7b in an aqueous LiClO₄ solution containing methylviologen (cation MV²⁺) under an O₂ atmosphere. The mechanism for the photoresponded cathodic current was explained in terms of an excitation of bis(terpyridinyl)ruthenium(II) complex [Ru(terpy)²₂⁺] by visible light, an electron transfer from the excited state [Ru(terpy)^2+*₂] to MV²⁺, reduction of Ru(terpy)³⁺₂ at an electrode, and oxidation of MV^+* with O₂.     

Synthesis, characterization and DFT investigation of aluminum complexes of aryl- substituted-8-hydroxyquinoline

New aryl substituted 8-hydroxyquinoline derivatives have been synthesized. The compounds were characterized by ¹H, ¹³C-NMR spectroscopy and mass spectrometry. The aluminum complexes of these derivatives show strong green emission in the range 530-535 nm with high quantum yield compared to the parent tris (8-hydroxyquinolinato)aluminum(III) complex. The structure of the aryl-substituted 8-hydroxyquinoline aluminum complexes in the ground state have been optimized at the B3LYP/6-31G* level of theory. The parent 8-hydroxyquinoline has also been examined using this method with the same basis set. A clear correlation between the shortening of the Al-N bond and red shift in the fluorescence emission band was observed. We have also found that substitution at the 5 and 7 position of the 8-hydroxyquinoline ligand cause simultaneous energy lowering of both highest occupied molecular orbital and the lowest unoccupied molecular orbital with the 5, 7-aryl substituted derivatives exhibiting the greatest effect.     

Synthesis,structure and electrochemical properties of tris (2-(2-pyridyl)-4-methylcarbonylquinoline) ruthenium(II) hexafluorophosphate

A novel ruthenium complex with 2-(2-pyridyl)-4-methylcarbonylquinoline ligand has been prepared and characterized: the first crystal structure of such complex along with its physical and chemical properties are also described.     

Synthesis,characterization, and catalytic behavior of mono- and bimetallic ruthenium(II) and iridium(III) complexes supported by pyridine-functionalized N-heterocyclic carbene ligands

We have prepared and characterized five unreported ruthenium(II) and iridium(III) complexes supported by pyridine-functionalized N-heterocyclic carbene ligands including a bimetallic iridium(III) complex. When activated, all complexes are active catalysts for the transfer hydrogenation of acetophenone.     

DFT study of electronic structure and properties of N,Si and Pd-doped carbon nanotubes

The electronic structure and properties of N, Si and Pd-doped (10,0) SWCNTs were studied by DFT method. N, Si and Pd dopings induced great structural modifications of the carbon nanotube walls. The type of SWCNT changes from semiconductor to metal conductor after N doping. The semiconducting property is well maintained for Si- and Pd-doped CNTs, however, the band gaps of Si- and Pd-doped CNTs decrease because of the interaction between doping atoms and nanotubes. The band gap of Pd-doped CNT (0.35?eV) is smaller than that of Si-doped one (0.39?eV). The impurity levels appear along with 2p orbitals of carbon atom, and DOS curves with different dopings change substantially. For N-doped CNT, carbons lose electrons, and nitrogen gains electrons, while carbons gain electrons, silicon and palladium lose electrons for Si- and Pd-doped CNTs. The different electronic structures caused by different dopings result in different properties of CNTs.     

Synthesis,structural characterization,opto-electrical properties of Ir(III) complexes with imidazolium-based carbene ligands

A series of Ir(III) complexes with N–heterocyclic carbenes (NHC) ligands (1–3) were synthesized and characterized. The opto-electrical properties of these complexes were investigated spectroscopically, electrochemically and theoretically. All complexes exhibit ligand-based ¹π,π* transitions in the UV region, ¹MLCT absorption in the UV region, and weak low energy ³π, π* transition in visible region. These complexes all exhibit blue phosphorescence at both room temperature and 77 K, which is dominated by ³π,π* character. DFT calculation results indicate their lowest unoccupied molecular orbitals (LUMO) from − 0.47 to − 0.33 eV and the highest occupied molecular orbitals (HOMO) from − 4.97 to − 5.33 eV. The opto-electrical properties can be influenced drastically by NHC ligands, which would be useful for rational design of optical functional materials.     

新型SalenCoX配合物的合成与表征

以(R,R)-N,N'-[2,2'-双(次氨基次甲基)]双[4-(亚甲基-N-吗啉基)-6-叔丁基)苯酚]-1,2-二苯基乙二胺为配体合成了6种SalenCoX配合物,其轴向离子分别为氯、溴、硝酸根、叠氮根、三氟醋酸根及四氟化硼根.利用1HNMR、13CNMR、FT-IR、UV-Vis、循环伏安法、ESI-MS和元素分析对配体及配合物进行了表征,证明了所得产物与目标化合物一致.     

Synthesis and electronic properties of double pincer-type cyclometalated iridium complexes

Double pincer-type cyclometalated iridium complexes were prepared based upon a few assumptions and their photophysical properties were examined.     

Synthesis, crystal structure, optical properties, DNA-binding and cell imaging of an organic chromophore

An organic chromophore (4-[N, N- bis(2′-chloroethyl)anilino] ethenyl N-methyl pyridinium-N- methyl iodide) L was synthesized and fully characterized by elemental analysis, IR, ¹HNMR spectra and single crystal X-ray diffraction analysis. One and two-photon fluorescence spectra for it were studied. Interestingly, L exhibited obvious two-photon absorption in the range from 700-850 nm in DMSO solution. The interactions between the chromophore and calf thymus DNA were investigated by absorption, fluorescence spectra and viscosity experiments. The results showed that the chromophore could interact with DNA in the mode of intercalation and be effectively used as fluorescent staining dye for cell imaging applications. Furthermore, the cell viability data for MCF-7 (Human breast carcinoma) cells indicated that the low-micromolar concentrations of the L are essentially non-toxic and can be applied in brighter two-photon fluorescent (TPF) bioimaging.     

Novel bioactive copper and nickel polymeric complexes: Synthesis,characterization, antimicrobial activity,and DFT calculations

Polymeric complexes, especially metal-containing polymers, possess aggregated medical applications, especially as antibacterial and antifungal agents. This work describes a facile procedure for producing a series of novel copper and nickel complexes of poly(2-hydroxyphenyl methacrylamide) and poly(2-carboxyphenyl methacrylamide). The polymeric ligands were synthesized through a multistep procedure. Firstly, 4-formylphenyl methacrylate was constructed by acylating 4-hydroxybenzaldehyde with methacryloyl chloride. Then, polymerization of the as-prepared monomer to obtain poly(4-formylphenyl methacrylate) using benzoyl peroxide as an initiator. Thirdly, the polymeric ligands PL1 and PL2 were achieved via exchange reactions between poly(4-formylphenyl methacrylate) and o-aminophenol and anthranilic acid, respectively. Consequently, the two ligands were reacted with copper and nickel acetates to afford four target complexes (Cu-PL1, Ni-PL1, Cu-PL2, and Ni-PL2). By FT-IR, ¹HNMR, UV-visible, and TGA analyses, the structures of PL1, PL2, and their complexes were investigated. Furthermore, the geometries of PL1, PL2, and their complexes were reported through a molecular modeling to investigate some interesting parameters such as the bond length, bond angle, charge on the atoms, the HOMO and LUMO using the Material Studio program. The calculation results illustrated that octahedral geometries are proposed for the synthesized metal complexes. The reported antimicrobial efficiency showed a strong potency for most synthesized compounds against the selected microbes, especially compounds Cu-PL1 and Cu-PL2 which are more effective than the standard against Candida albicans.     

Synthesis,characterization and catalytic activities of ruthenium complexes containing triphenylphosphine/triphenylarsine and tetradentate Schiff bases

Ruthenium(II) complexes of the type [Ru(CO)(B)(L)] (B=AsPh₃, pyridine, piperidine or morpholine; L=dianion of tetradentate Schiff bases) have been synthesized and characterized by physico-chemical methods. These complexes are found to be effective catalysts in the oxidation of primary and secondary alcohols using N-methylmorpholine-N-oxide as oxidant. The catalytic activity of these triphenylarsine complexes have been compared with that of triphenylphosphine complexes and with similar ruthenium(III) complexes. The formation of high valent Ruⁿ⁺²O species as catalytic intermediate is proposed for the catalytic processes.     

Four new cyclometalated phenylisoquinoline-based Ir(III) complexes: Syntheses,structures, properties and DFT calculations

Four new cyclometalated phenylisoquinoline-based iridium(III) complexes [Ir(C^∧N)₂(bipy)]PF₆ (5a–5d) (bipy = 2,2′-bipyridine) have been synthesized and fully characterized, where the C^∧N ligands are 1-(4-(trifluoromethyl)phenyl)isoquinoline, 4-(isoquinolin-1-yl)benzaldehyde, 4-(isoquinolin-1-yl)benzonitrile and 1-(3-fluoro-4-methylphenyl)isoquinoline, respectively. The crystal structures of 5a and 5c have been determined. The photophysical and electrochemical properties of these new complexes 5a–5d have been studied. All Ir(III) complexes exhibit orange phosphorescence in dichloromethane solution at room temperature with a maximum at 593–618 nm, quantum yield of 0.046–0.16. The frontier molecular orbital diagrams and the lowest-energy electronic transitions of 5a–5d have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT).     

Synthesis, characterization, and thermal properties of poly(siloxane-carborane)s

Three exactly alternating carborane-siloxane polymers P1, P2, and P3, have been synthesized by the polycondensation of 1,7-bis(dimethylhydroxylsilyl)-m-carborane and cyclotrisilazanes in the presence of (NH₄)₂SO₄. The reaction shows a new and convenient synthesis of poly(carborane-siloxane)s, and the first example of stoichiometric polycondensation of cyclosilazanes with diols. The new polymers P2 and P3 could be converted into thermosets at elevated temperature through the cross-linking of pendant vinyl groups. The structures of the polymers were fully characterized. Thermogravimetric analysis (TGA) showed the superior thermal stability of the polymers and thermosets, with their char yields of over 83% both in air (800 °C) and nitrogen (1000 °C). The microstructure of the chars was studied by scanning electron microscopy (SEM). It was found that the cross-linking of vinyl groups helped in enhancing the thermal stabilities of the polymers and keeping the integrity of the chars. The results suggest their potential utility under severe thermal and/or thermo-oxidative conditions.     

Synthesis, structure and catalytic activities for the hydrogen transfer reactions of the ruthenium(II) carbonyl chloride complexes with pyridine-2,6-diimine

Two Ru(II) carbonyl chloride complexes with pyridine-2,6-diimine, (L)Ru(CO)Cl₂ (L = 2,6-diacetylpyridinebis(2,4,6-trimethylanil), 1; L = 2,6-diacetylpyridinebis(2,6-diisopropylanil), 2) have been synthesized and characterized. The structure of compound 1 has been determined by X-ray crystallography, which show the distorted octahedral geometry around Ru(II). Complexes 1 and 2 have been proved to be active in the transfer hydrogenation of acetophenone by propan-2-ol.     

Synthesis, characterization and properties of tetramethyl stilbene-based epoxy resins for electronic encapsulation

Two novel tetramethyl stilbene-based novolac (II and IV) were synthesized from 2,6-dimethyl phenol and chloroacetaldehyde dimethylacetal or chloroacetone, and then the resulted novolacs were epoxidized to tetramethyl stilbene-based epoxy resins (III and V). The proposed structures were confirmed by FTIR, elemental analysis, mass spectra, NMR spectra and epoxy equivalent weight titration. The synthesized tetramethyl stilbene-based epoxy resins were cured with 4,4-diaminodiphenyl methane (DDM) and 4,4-diaminodiphenyl sulfone (DDS). Thermal properties of cured epoxy resins were studied using dynamic mechanical analyzer, differential scanning calorimeter, thermal expansion analyzer and thermal gravimetric analyzer (TGA). These data were compared with that of the commercial tetramethyl biphenol (TMBP) epoxy system. According to the experimental data, the order of T_g for cured epoxy system is III>TMBP>V. The order of moisture absorption for cured epoxy system is V<III<TMBP. According to TGA, the 5% degradation temperatures in nitrogen atmosphere were in the range 370-377 and 397-412 °C for DDM and DDS curing systems, respectively. In air atmosphere, the 5% degradation temperatures were in the range 372-385 and 410-411 °C for DDM and DDS curing systems, respectively. The CTE is in inverse order with T_g, therefore, III/DDS<TMBP/DDS<V/DDS.     

水杨醛-甘氨酸Schiff碱镧配合物的合成及表征

以甘氨酸和水杨醛为基本构造元件，合成了水杨醛-甘氨酸Schiff碱，并所得配体与硝酸镧（Ⅲ0）反应生成了镧配合物，通过元素分析、红外光谱和紫外光谱对配体和配合物进行了表征。