Mono- and dinuclear rhenium(I) compounds with bidentate benzimidazole chelators

A mononuclear rhenium(I) complex, fac-[Re(CO)₃(bzch)Cl] (1), where bzch = 2-benzimidazole-4H-chromen-4-one, was isolated from the equimolar reaction between the Schiff base ligand 2-(2-aminophenyliminomethyl)-4H-chromen-4-one (H₂pch) and [Re(CO)₅Cl]. The 1:2 molar ratio reactions between [Re(CO)₅Cl] and N-(2-hydroxybenzylidene)-benzimidazole (Hbzp) afforded a dinuclear rhenium(I) compound, (μ-bzp)₂[Re(CO)₃]₂ (2). These new rhenium(I) compounds were characterized by NMR, UV–vis, IR, and emission spectroscopy, as well as conductance measurements and single crystal X-ray diffraction. The emission spectra for 1 in dichloromethane were well-resolved and could be deconvoluted into three main bands. The emission spectra for 2 were red-shifted by > 140 nm and markedly broadened relative to those of 1.     

Sensing of insulin fibrillation using alkoxy-bridged binuclear rhenium(I) complexes

For the first time we report the simple, cost-effective, sensitive detection of human insulin fibrils using an alkoxy-bridged binuclear rhenium(I) complexes by the enhancement in luminescence intensity, emission lifetime and the formation of fibrils. The Re(I) complexes are weakly emissive, when it is dissolved with native insulin in an incubation buffer, but it becomes highly luminescent after the formation of insulin fibrils. This binding of human insulin fibrils is attributed to the hydrophobic as well as π − π stacking interaction of naphthalene moiety present in rhenium(I) complexes.     

A new cyclometalated rhenium(I) complex

Reaction of Re(CO)₅Cl with 2-phenylbenzothiazole (HΦBT) afforded the cyclometalated Re(CO)₄(ΦBT) complex with the molecular structure of the obtained product confirmed by X-ray investigations. Re(CO)₄(ΦBT) shows intense, hardly dependent on environment, luminescence originating from the π–π* ΦBT intraligand electronic transition. The investigated Re(CO)₄(ΦBT) complex can be considered as a potentially applicable “triplet emitter” for OLED devices.     

Absorption of NO x in packed column (I)

A mathematical model for an absorption of nitrogen oxides into water in packed column was developed based on the mass-transfer coefficient in packed column and the chemical reaction accompanying NO _x absorption produces HNO₃ and HNO₂ in the liquid phase. The subsequent dissociation of HNO₂ in the liquid-phase results in the formation of HNO₃ and NO gas, and then this NO gas follows to be oxidized by O₂ in air. The important factors influenced on the absorption of NO _x are the oxidation state of NO gas and the partial pressure of nitrogen oxides in the gas. The efficiency of NO _x absorption increases with the increase of the partial pressure of NO _x . The most critical value for using the model is the constant of .The selection of 11×10⁻⁴kg·mol/atm·m²·sec for resonable for this model.     

Photochromic behavior of a bisthienylethene bearing Cu(I)-1,10-phenanthroline complexes

A novel diarylethene having a 1,10-phenanthroline unit at each end of the molecule has been synthesized. Among the metal ions, it formed a stable complex with Cu(I) ions in acetonitrile. Rational structures of the Cu(I) complexes of the colorless and the photo-generated blue form have been given by PM3 semiempirical molecular orbital calculations to be 2:2 cyclic complexes for both isomers, with the complex of the open form belonging to the C₂ symmetry group while the complex of the closed form belongs to the D₂ symmetry group. Although the ring-closing quantum yield for free diarylethene in acetonitrile was 0.75, that for the complex was 0.026, due to the long distance of the bond-forming carbon atoms in the rigid (open form)₂-Cu(I)₂ complex.     

Photoluminescence of 8-quinolinolato(trioxo)rhenium(VII)

The complex Re^VIIO₃(oxinate) (oxine=8-quinolinol or 8-hydroxyquinoline) shows a green fluorescence at λ_max=511 nm with φ=0.012 and a very weak red phosphorescence at λ_max=645 nm. Both emissions originate from the lowest-energy ππ* intraligand state of the oxinate ligand. Owing to the d⁰ electron configuration and the high oxidation state of rhenium the heavy atom effect transmitted to the π-electron system of the oxinate ligand is very weak.     

A series of new emissive mononuclear copper(I) bipyridyl complexes bearing the methoxycarbonyl groups

A new series of mononuclear copper(I) complexes 1–3 possessing functionalized 6-methoxycarbonyl-2,2′-bipyridine and phosphine mixed ligands have been synthesized and characterized. Each Cu(I) atom gives an N₂P₂ distorted tetrahedral configuration, in which the dihedral angles between two pyridyl rings follow a ranking of 1 (4.640°) < 2 (av. 9.065°) < 3 (15.648°), while a reverse order lies in the dihedral angles between the methoxycarbonyl and its conjoined pyridyl ring (1 (15.224°) > 2 (av. 8.983°) > 3 (2.786°)). Complexes 1–3 show a weak low-energy absorption band at 330–500 nm in CH₂Cl₂ solution, ascribed to charge-transfer transitions with appreciable ¹MLCT character, as supported by TD-DFT calculations. The solid-state luminescence is observed in 1–3 at room temperature, which is affected by the phosphine, the substituents on the 2,2′-bipyridyl, and the above-mentioned dihedral angles.     

Structural and photophysical characterization of gold(I) complexes bearing naphthyl chromophores

We prepared two chlorido-gold(I) complexes of the type L–Au–Cl bearing a naphthyl moiety: Complex 1 with L = tris-1-naphthyl-phosphine shows standard linear coordination without further aggregation in the solid state. Complex 2 with L = 2-naphthyl-isonitrile is engaged in a complex network of aurophilic and π–π interactions. The two complexes show similar luminescence behaviour in solution at room temperature with both intraligand fluorescence and phosphorescence. At 77 K the emission spectra are dominated by intraligand phosphorescence, which is typical of gold complexes with extended π-chromophores.     

Amorphization of pharmaceutical compound by co-precipitation using supercritical anti-solvent (SAS) process (Part I)

The aim of this work is to investigate the feasibility of using supercritical anti-solvent (SAS) co-precipitation process to influence the crystallinity or amorphous character of a crystalline non-steroidal anti-inflammatory drug (NSAID), indomethacin (IDMC) for solubility enhancement. Co-precipitations of IDMC and the water-soluble polymer excipient poly(vinylpyrrolidone) (PVP) have been prepared by SAS. The SAS co-precipitates with drug to polymer ratios of 85:15, 50:50 and 20:80 were generated using supercritical carbon dioxide as anti-solvent. The untreated and SAS powders (before and after storage) were characterised using scanning electron microscopy (SEM, morphology), powder X-ray diffractometry (PXRD, crystallinity), USP dissolution tester and thermogravimetric analysis. In addition, stability stress tests on SAS co-precipitates on open pans were carried out at 75% RH and room temperature or 40 °C in order to evaluate their physical stability. SAS co-precipitates with PVP contents more than 50 wt.% were X-ray amorphous and remained stable after 7 months storage at 75% RH and room temperature or 40 °C. It was demonstrated that the drug to polymer ratio influenced amorphous content of the SAS co-precipitates. By using different polymer ratios, the morphologies of a drug–polymer composite can be varied. TGA analyses revealed that the composition of SAS co-precipitates were consistent with the experimentally designed composition. Amorphous form of IDMC produced by SAS has improved dissolution properties as compared to the crystalline form. This form is also stable under stress test conditions compared as with spray-dried amorphous indomethacin. It is suggested that PVP excipient could be a suitable “amorphous inducing and stabilizing” agent for SAS process.     

Bonding of rhenium(V) to diethylenetriaminepentaacetate functional groups of a polymethacrylate support

The bonding of rhenium to diethylenetriaminepentaacetic acid functional groups of a polymeric methacrylate matrix was studied. Diamagnetic complexes were formed of Re(V) with the heterogeneous coordination sphere containing atoms of chlorine and multiply bonded oxygen in addition to carboxylic groups, which are the only groups of the polymeric support functioning as ligands in the bonding to the metal. The rhenium complexes were examined by IR and UV-VIS spectroscopy and by magnetic moment measurements.     

Synthesis and properties of novel electrophosphorescent conjugated polyfluorenes based on aminoalkyl-fluorene and bipyridine with rhenium(I) complexes

Novel bipyridine-based aminoalkyl-polyfluorene and their corresponding rhenium complex-contained copolymers with different rhenium complex contents in polymer backbone were synthesized by Suzuki polymerization and post-polymerization, respectively. The aminoalkyl-polyfluorenes have good solubility in organic solvents and also are able to dissolve in methanol by adding a few drops of acetic acid. The solubility in polar solvents such as alcohol provides a great advantage in fabrication of multi-layer PLEDs. However, the rhenium complex-based copolymers become insoluble in common organic solvents; instead have a good solubility in polar solvents, such as methanol and DMF. The optoelectronic and electroluminescent properties of these copolymers (bipyridine- and rhenium-based copolymers) were investigated. The electroluminescent properties of these copolymers were found to have similar device performances by using high work function metal (Al) and low work function metal (Ba) as cathodes. We also found that these rhenium copolymers can be used as the electron transport layer in PLED. After inserting a thin rhenium copolymer layer between emission layer (P-PPV or PFO-DBT15) and cathode, a great improvement in EL performance could be achieved.     

Decarboxylation of 5-amino-orotic acid and a Schiff base derivative by rhenium(V)

The reaction of 5-amino-orotic acid (H₂aor) with trans-[ReOBr₃(PPh₃)₂] in 2-propanol produced the complex [Re^V(apd)Br(aor)(PPh₃)₂] (1, apd^2 − = 5-imidopyrimidine-2,4-dione). The ligand apd^2 − was formed by the decarboxylation of H₂aor, and it is coordinated via the dinegative imido nitrogen only. The Schiff base derivative of H₂aor, salicylimine-orotic acid {5-(2-hydroxy-benzylideneamino)-1,2,3,6-tetrahydro-2,6-dioxopyrimidine-4-carboxylic acid; H₂sor}, was also decarboxylated in the reaction with trans-[ReOI₂(OEt)(PPh₃)₂] in ethanol to form [Re^III(cor)I(PPh₃)₂]I (2, Hcor = 5-(2-hydroxybenzylideneamino)-pyrimidine-2,4(1H,3H)-dione). Decarboxylation of H₂sor was not observed in its reaction with trans-[ReOCl₃(PPh₃)₂], which led to the isolation of [ReOCl(sor)(PPh₃)] (3), in which sor^2 − is coordinated as a tridentate ligand as expected. Spectroscopic results and the X-ray crystal structures of compounds 1–3 are also presented.     

N,O-羧甲基壳聚糖与镨配合物的制备

用羧甲基壳聚糖与硝酸镨反应,制备了羧甲基壳聚糖-镨稀土配合物。用红外光谱、X-射线光电子能谱(XPS)和扫描电镜等分析测试手段对配合物进行表征。讨论了时间和溶液的酸度对配合物形成的影响。对羧甲基壳聚糖-镨配合物配位机理进行了初步的研究,羧甲基壳聚糖-镨配合物中羧甲基壳聚糖中不仅羧基参与了配位,氨基上的氮原子和羟基氧原子也参与了配位。羧甲基壳聚糖-镨配合物和羧甲基壳聚糖相比,表面结构疏松。     

A novel terpyridyl rhenium(II) complex – Synthesis,spectroscopic characterization and X-ray structure

The reaction of the [ReOBr₃(PPh₃)₂] complex with 2,2′:6′,2″-terpyridine (terpy) in the presence of tripenylphosphine has been examined and novel [ReBr(terpy)(PPh₃)₂]ReO₄ · H₂O · CH₃OH complex – has been obtained. It has been studied by IR, UV–vis spectroscopy and X-ray crystallography.     

Crosslinking of poly(vinyl chloride) with bismaleic compound. I. Crosslinking mechanism

Crosslinked poly(vinyl chloride) (PVC) was obtained by using bismaleic compound (BMC). Styrene, as auxiliary crosslinker, can markedly promote the crosslinking course. After having carefully studied the gelling behavior of PVC in crosslinking, and the reactivity of styrene and BMC with PVC, the crosslink mechanism was suggested. The main crosslink reaction is the bridging of bismaleic compound between PVC macroradicals, which were created by thermal degradation of PVC and disproportionation of PVC with initiator radicals and styrene radicals. The first step of crosslink reaction was the BMC grafting on PVC macroradicals. Then styrene copolymerizes with active center bearing on bismaleic compound to propagate graft chain, which make bridging reaction easier to take place. At last, PVC^* reacted with another double bond possessed by grafted BMC to form network structure     

Pyrazolyl-diamine ligands that bear anthracenyl moieties and their rhenium(I) tricarbonyl complexes: synthesis, characterisation and DNA-binding properties

Two novel families of pyrazolyl-diamine ligands that bear an anthracen-9-yl group as a DNA-binding fragment, pz*(CH2)2NH(CH2)2NHCH2-9-anthryl (pz*=pz (L(1)), 3,5-Me2pz (L2)) and pz*(CH2)2NH(CH2)2NH(2 (pz*=4-(9-anthrylmethyl)pz (L3), 3,5-Me2-4-(9-anthrylmethyl)pz (L4)), have been prepared and fully characterised. In the case of L2-L4, the evaluation of their coordination capability towards the fac-[Re(CO)3]+ core led to the synthesis of the organometallic complexes fac-[Re(CO)(3){3,5-Me(2)pz(CH2)2NH(CH2)2NHCH2-9-anthryl}]Br (7) and fac-[Re(CO)3{4-(9-anthrylmethyl)pz*(CH2)2NH(CH2)2NH2}]Br (pz*=pz (8), 3,5-Me2pz 9). The interaction of the novel pyrazole-diamine ligands and the rhenium(I) complexes with calf thymus (CT) DNA has been investigated with a variety of spectroscopic techniques (UV-visible, fluorescence, circular dichroism (CD) and linear dichroism (LD)). All of the evaluated compounds have a moderate affinity to CT DNA (3.46x10(3)相似文献   

Ag(I)(Et(2)PCH(2)CH(2)PPh(2))(2)]NO(3): An Antimitochondrial Silver Complex

The silver(I) complex [Ag(eppe)(2)]NO(3) (eppe = Et(2)PCH(2)CH(2)PPh(2)) is shown by X-ray crystallography to be tetrahedral with Ag - PEt(2) and Ag - P Ph(2) bond lengths of 2.482 and 2.518 A, respectively. The complex is selectively antimitochondrial and inhibits the growth of a number of yeast strains in non-fermentable media at concentrations as low as 2.5 muMu and induces the mitochondrial mutation petite The effect is largely reversed by the presence of aspirin. The complex is shown to be stable in the cell culture media and in the presence of glutathione, but readily reacts with disulfides of oxidized glutathione and serum albumin. Surprisingly, neither [Au(eppe)(2)]Cl nor [Au(eppe)(2)]Cl (dppe = Ph(2)PCH(2)CH(2)PPh(2)) showed any mitochondrial selectivity in the same screening protocol.     

Bis(imido) rhenium complexes bearing C- or N-capped ‘tripodal’ ligands: Bi- versus tri-dentate ligation

The differing geometrical constraints of the tripodal ligands tris(hydroxyphenyl)amine (N-cappedH₃) and tris(3,5-di-t-Bu-2-hydroxyphenyl)methane (C-cappedH₃) led, on reaction with [Re(t-BuN)₃(OSiMe₃)], to the isolation of the complexes [Re(t-BuN)₂(N-capped)] (1) and [Re(OSiMe₃)(t-BuN)₂(C-cappedH)] (2), respectively. Both 1 · 1/2MeCN and 2 have been structurally characterized using X-ray synchrotron radiation.     

D318阴离子交换树脂对铼（VII）的吸附

The adsorption and mechanism of Re(VII) on resin D318 were studied using chemical methods and IR spectrometry. At pH 5.2, the static and dynamic saturation adsorption capacities were 351.4 and 366.5 mg&;#8226;g&;#61485;1, respectively. The adsorption behavior obeyed the Freundlich empirical equation and the adsorption rate constant k298 was 6.37×10&;#61485;4 s&;#61485;1. The desorption percentage was up to 99.7% when 2.0 mol&;#8226;L&;#61485;1 KSCN was used for dynamic desorption.     

Dicopper(I) and disilver(I) complexes of a thiophene-derived Schiff base macrocycle

Dicopper(I) and disilver(I) complexes of a tetraimine Schiff base macrocycle derived from the cyclocondensation of thiophene-2,5-dicarbaldehyde with 1,4,7-triazaheptane (1) have been synthesised and characterised. The structure of Cu₂(1)(BF₄)₂·2CH₃CN is given.