A new phosphorescent heteroleptic cuprous complex with a neutral 2‐methylquinolin‐8‐ol ligand: synthesis,structure characterization,properties and TD–DFT calculations

Luminescent Cu^I complexes have emerged as promising substitutes for phosphorescent emitters based on Ir, Pt and Os due to their abundance and low cost. The title heteroleptic cuprous complex, [9,9‐dimethyl‐4,5‐bis(diphenylphosphanyl)‐9H‐xanthene‐κ²P ,P ](2‐methylquinolin‐8‐ol‐κ²N ,O )copper(I) hexafluorophosphate, [Cu(C₁₀H₉NO)(C₃₉H₃₂OP₂)]PF₆, conventionally abbreviated as [Cu(Xantphos)(8‐HOXQ)]PF₆, where Xantphos is the chelating diphosphine ligand 9,9‐dimethyl‐4,5‐bis(diphenylphosphanyl)‐9H‐xanthene and 8‐HOXQ is the N ,O‐chelating ligand 2‐methylquinolin‐8‐ol that remains protonated at the hydroxy O atom, is described. In this complex, the asymmetric unit consists of a hexafluorophosphate anion and a whole mononuclear cation, where the Cu^I atom is coordinated by two P atoms from the Xantphos ligand and by the N and O atoms from the 8‐HOXQ ligand, giving rise to a tetrahedral CuP₂NO coordination geometry. The electronic absorption and photoluminescence properties of this complex have been studied on as‐synthesized samples, whose purity had been determined by powder X‐ray diffraction. In the detailed TD–DFT (time‐dependent density functional theory) studies, the yellow emission appears to be derived from the inter‐ligand charge transfer and metal‐to‐ligand charge transfer (M +L ′)→LCT excited state (LCT is ligand charge transfer).     

Structural,spectroscopic, luminescence sensing and TD–DFT theoretical studies of a CuP2N-type complex

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title heteroleptic cuprous complex, [2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl-κ²P,P′](2-phenylpyridine-κN)copper(I) hexafluoridophosphate, rac-[Cu(C₄₄H₃₂P₂)(C₁₁H₉N)]PF₆, conventionally abbreviated rac-[Cu(BINAP)(2-PhPy)]PF₆ ( I ), where BINAP and 2-PhPy represent 2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl and 2-phenylpyridine, respectively, is described. In this complex, the asymmetric unit consists of a hexafluoridophosphate anion and a heteroleptic cuprous complex cation, in which the cuprous centre in a CuP₂N coordination triangle is coordinated by two P atoms from the BINAP ligand and by one N atom from the 2-PhPy ligand. Time-dependent density functional theory (TD–DFT) calculations show that the UV–Vis absorption of I should be attributed to ligand-to-ligand charge transfer (LLCT) characteristic excited states. It was also found that the paper-based film of this complex exhibited obvious luminescence light-up sensing for pyridine.     

Silver(I), nickel(II) N-heterocyclic carbene complexes based on bidentate bis-imidazolium salt with a quinoxaline linker: syntheses,structures, and characterization

Quinoxaline-bridged bidentate bis-imidazolium dicarbene ligand 1,1′-(quinoxaline-2,3-diyl)bis(3-methyl-1H-imidazol-3-ium) hexafluorophosphate salt H₂L·2PF₆ (3) was prepared by a two-step reaction based on 2,3-bis(imidazol-1-yl)quinoxaline (1). First, the 2,3-bis(imidazol-1-yl)quinoxaline reacted with CH₃I resulting in the 1,1′-(quinoxaline-2,3-diyl)bis(3-methyl-1H-imidazol-3-ium) iodide salt H₂L·2I (2), then through anion exchange reactions with NH₄PF₆ in water produced the desired bis-imidazolium bidentate ligand H₂L·2PF₆ (3). Reaction of the bidentate bis-imidazolium ligands H₂L·2PF₆ (3) with Ag₂O in acetonitrile gave the macrocyclic binuclear silver(I) carbene complex [Ag₂(L)₂]·2PF₆·CH₃CN (4). Nickel carbene complex [Ni(L)PPh₃Cl]·PF₆·2DMSO (5) was obtained via transmetalation of 4 with Ni(PPh₃)₂Cl₂ in DMSO. The bidentate carbene ligand is a chelating ligand in 5, while bridging in 4. The imidazolium ligand H₂L·2PF₆ (3) and transition metal carbene complexes 4 and 5 have been fully characterized by elemental analysis, NMR, ESI-MS spectroscopy, and X-ray diffraction analyses. Furthermore, the UV and luminescent properties of 3–5 were also studied.     

Four-coordinate N-heterocyclic carbene (NHC) copper(I) complexes with brightly luminescence properties

Three four-coordinate N-heterocyclic carbene (NHC) copper(I) complexes, [Cu(Py-Im)(POP)](PF₆) (P1), [Cu(Py-BenIm)(POP)](PF₆) (P2), and [Cu(Py-c-BenIm)(POP)](PF₆) (P3) (Py-Im = 3-methyl-1-(pyridin-2-yl)-1H-imidazolylidene, Py-BenIm = 3-methyl-1-(pyridin-2-yl)-1H-benzo[d]imidazolylidene, Py-c-BenIm = 3-methyl-1-(pyridin-2-ylmethyl)-1H-benzo[d]imidazolylidene, POP = bis([2-diphenylphosphino]-phenyl)ether), have been synthesized without transmetalation of the NHC–Ag(I) complex for the first time. The photophysical properties of the resultant NHC–Cu(I) complexes have been systematically investigated via spectroscopic methods. All complexes exhibit good photoluminescence properties with long excited-state lifetimes and moderate quantum yields. Density functional theory and time dependent density functional theory calculations were employed to rationalize the photophysical properties of the NHC–Cu(I) complexes.     

A new heteroleptic phosphorescent cuprous complex supported by a BINAP ligand: synthesis,structure, luminescence properties and theoretical analyses

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The heteroleptic cuprous complex solvate rac‐(acetonitrile‐κN)(3‐aminopyridine‐κN)[2,2′‐bis(diphenylphosphanyl)‐1,1′‐binaphthyl‐κ²P,P′]copper(I) hexafluoridophosphate dichloromethane monosolvate, [Cu(C₅H₆N₂)(C₂H₃N)(C₄₄H₃₂P₂)]PF₆·CH₂Cl₂, conventionally abbreviated as [Cu(3‐PyNH₂)(CH₃CN)(BINAP)]PF₆·CH₂Cl₂, ( I ), where BINAP and 3‐PyNH₂ represent 2,2′‐bis(diphenylphosphanyl)‐1,1′‐binaphthyl and 3‐aminopyridine, respectively, is described. In this complex solvate, the asymmetric unit consists of a cocrystallized dichloromethane molecule, a hexafluoridophosphate anion and a complete racemic heteroleptic cuprous complex cation in which the cuprous centre, in a tetrahedral CuP₂N₂ coordination, is coordinated by two P atoms from the BINAP ligand, one N atom from the 3‐PyNH₂ ligand and another N atom from a coordinated acetonitrile molecule. The UV–Vis absorption and photoluminescence properties of this heteroleptic cuprous complex have been studied on polycrystalline powder samples, which had been verified by powder X‐ray diffraction before recording the spectra. Time‐dependent density functional theory (TD‐DFT) calculations and a wavefunction analysis reveal that the orange–yellow phosphorescence emission should originate from intra‐ligand (BINAP) charge transfer mixed with a little of the metal‐to‐ligand charge transfer ³(IL+ML)CT excited state.     

Photoinitiated Charge Transfer in a Triangular Silver(I) Hydride Complex and Its Oxophilicity

The photoexcitation of a triangular silver(I) hydride complex, [Ag₃(μ₃-H)(μ₂-dcpm)₃](PF₆)₂ ([ P ](PF₆)₂, dcpm=bis(dicyclohexylphosphino)methane), designed with “UV-silent” bis-phosphine ligands, provokes hydride-to-Ag₃ single and double electron transfer. The nature of the electronic transitions has been authenticated by absorption and photodissociation spectroscopy in parallel with high-level quantum-chemical computations utilizing the GW method and Bethe–Salpeter equation (GW-BSE). Specific photofragments of mass-selected [ P ]²⁺ ions testify to charge transfer and competing pathways resulting from the unique [Ag₃(μ₃-H)]²⁺ scaffold. This structural motif of [ P ](PF₆)₂ has been unequivocally verified by ¹H NMR spectroscopy in concert with DFT and X-ray diffraction structural analysis, which revealed short equilateral Ag–Ag distances (d_AgAg=3.08 Å) within the range of argentophilic interactions. The reduced radical cation [ P ] ^{. +} exhibits strong oxophilicity, forming [ P +O₂] ^.+ ,which is a model intermediate for silver oxidation catalysis.     

Efficient synthesis of a new ditopic bipyridine–terpyridine bridging ligand

Abstract

The novel bipyridine–terpyridine–phenazine ligand 6-pyrid-(tetrapyrido[2,3-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine (I) was prepared by condensation reaction of 5,6-diamino-l,10-phenanthroline (4) and 2-(pyrid-2′-yl)-1,10-phenanthroline-5,6-dione (6) and characterized using conventional methods. Poor solubility of the ligand led us to the preparation of its Ru(II) complexes to investigate the change in its solubility for further characterizing the ligand on the metal ion. [Ru(ttp)(I)](PF₆)₂ complex was prepared using the reaction of the ligand (I) and [Ru(ttp)Cl₃] complex, where ttp is 4′-(4-Methylphenyl)-2,2′:6′,2′′-terpyridine. A different route for the preparation of [Ru(ttp)(I)](PF₆)₂ was introduced. Synthesis of the ligand (I) on the complex by a condensation reaction of [Ru(ttp)(6)](PF₆)₂, where ligand (6) is 2-(pyrid-2′-yl)-1,10-phenanthroline-5,6-dione, with 5,6-diamino-l,10-phenanthroline (4) was conducted. The spectroscopic measurements of both products which have been obtained through the two different routes were compared. We observed that the NMR, LC-MS, and UV spectra of the both products were identical.     

A Stable Homoleptic Organometallic Iron(IV) Complex

A homoleptic organometallic Fe^IV complex that is stable in both solution and in the solid state at ambient conditions has been synthesized and isolated as [Fe(phtmeimb)₂](PF₆)₂ (phtmeimb=[phenyl(tris(3-methylimidazolin-2-ylidene))borate]⁻). This Fe^IV N-heterocyclic carbene (NHC) complex was characterized by ¹H NMR, HR-MS, elemental analysis, scXRD analysis, electrochemistry, Mößbauer spectroscopy, and magnetic susceptibility. The two latter techniques unequivocally demonstrate that [Fe(phtmeimb)₂](PF₆)₂ is a triplet Fe^IV low-spin S=1 complex in the ground state, in agreement with quantum chemical calculations. The electronic absorption spectrum of [Fe(phtmeimb)₂](PF₆)₂ in acetonitrile shows an intense absorption band in the red and near IR, due to LMCT (ligand-to-metal charge transfer) excitation. For the first time the excited state dynamics of a Fe^IV complex was studied and revealed a ≈0.8 ps lifetime of the ³LMCT excited state of [Fe(phtmeimb)₂](PF₆)₂ in acetonitrile.     

联吡啶[3,2-a：2’,3-c]-7-氮杂-吩嗪铜(I)配合物的合成、表征及其与DNA的相互作用

合成了邻菲罗啉衍生物联吡啶[3,2-a:2',3'-c]-7-氮杂-吩嗪(dpapz)及其铜(I)配合物[Cu(dpapz)₂]PF₆, 利用核磁共振氢谱(¹H NMR), 傅里叶变换红外(FTIR)光谱, 高分辨质谱(HR ESI-MS)等对合成的化合物进行了表征.采用紫外-可见吸收光谱,荧光光谱, DNA熔解温度实验和循环伏安方法研究了dpapz和[Cu(dpapz)₂]PF₆与小牛胸腺DNA(CT DNA)的相互作用. 配体dpapz与小牛胸腺DNA(CT DNA)作用时未观察到吸收峰红移并且减色效应较小(<30%), 且DNA熔解温度也上升较小(ΔT_m=7.8 ℃), 说明dpapz以沟槽结合的方式与CT DNA相互作用. 而[Cu(dpapz)₂]PF₆与CT DNA作用时, 可观测到较小的吸收峰红移(2-3 nm)和较大的减色效应(>50%), 同时DNA熔解温度上升较大(ΔT_m=11.1 ℃), 表明[Cu(dpapz)₂]PF₆以静电相互作用和部分扦插的方式与DNA结合. 溴乙锭(EB)荧光竞争实验和循环伏安实验进一步证实了这一结论. 配体dpapz和[Cu(dpapz)₂]PF₆与DNA的结合常数分别为2.88×10⁵和5.32×10⁵ mol·L^-1. 光照条件下, [Cu(dpapz)₂]PF₆产生单重态氧的能力与dpapz相当, 但产生超氧负离子自由基的能力要弱于dpapz. 活性氧猝灭实验表明, 超氧负离子自由基、单重态氧和羟基自由基均参与了dpapz和[Cu(dpapz)₂]PF₆对DNA的光损伤作用. [Cu(dpapz)₂]PF₆对DNA的亲和性要高于对dpapz的, 使得[Cu(dpapz)₂]PF₆对质粒DNA的光损伤效率明显强于dpapz.     

A new heteroleptic cuprous complex with strong yellow photoluminescence

In the title heteroleptic cuprous complex, (acetonitrile‐κN)({2‐[2‐(diphenylphosphanyl)phenoxy]phenyl}diphenylphosphane‐κ²P,P′)[2‐(pyridin‐4‐yl‐κN)‐1,3‐benzoxazole]copper(I) hexafluoridophosphate, [Cu(C₃₆H₂₈OP₂)(CH₃CN)(C₁₂H₈N₂O)]PF₆, conventionally abbreviated [Cu(POP)(CH₃CN)(4‐PBO)]PF₆, where POP is the diphosphane ligand {2‐[2‐(diphenylphosphanyl)phenoxy]phenyl}diphenylphosphane and 4‐PBO is the N‐containing ligand 2‐(pyridin‐4‐yl)‐1,3‐benzoxazole, the asymmetric unit consists of a hexafluoridophosphate anion and a whole mononuclear cation, where the Cu^I centre is coordinated by two P atoms from the POP ligand, by one N atom from the 4‐PBO ligand and by the N atom of the coordinated acetonitrile molecule, giving rise to a CuP₂N₂ distorted tetrahedral coordination geometry. The electronic absorption, photoluminescence and thermal stability properties of this complex have been studied on as‐synthesized samples, which had previously been examined by powder X‐ray diffraction. A yellow emission signal is attributed to an excited state arising from metal‐to‐ligand charge transfer (MLCT).     

Heteroleptic [Cu(NN)P2]+-type cuprous complexes and their structural modulation on phosphorescent color: Synthesis,structural characterization,properties, and theoretical calculations

Four new heteroleptic [Cu(NN)P₂]⁺-type cuprous complexes— 1 -TPP, 2 -POP, 3 -Xantphos, and 4 -DPPF—were designed and synthesized using a diimine ligand 2-(2′-pyridyl)benzoxazole (2-PBO) and different phosphine ligands (TPP, triphenylphosphine; POP, bis[2-(diphenylphosphino)phenyl]ether; Xantphos, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; DPPF, 1,1′-bis(diphenylphosphino)-ferrocene). All complexes were characterized using single-crystal X-ray diffraction, spectroscopic analysis (infrared, UV–Vis.), elemental analysis, and photoluminescence (PL). Single-crystal X-ray diffraction revealed complexes 1 – 4 as isolated cation complex structures with a tetrahedral CuN₂P₂ coordination geometry and diverse P–Cu–P angles. Their UV–Vis. absorption spectra exhibited a blue-shift sequence in wavelength with an enlarged P–Cu–P angle from 4 to 2 then to 3 and then to 1 . The PL emission peaks of 1 – 3 also exhibited a similar blue-shift sequence ( 2 → 3 → 1 ). Their PL lifetime in microseconds (~7.5, 5.1, and 4.7 μs for 1 , 2 , and 3 , respectively) indicated that their PL behavior represents phosphorescence. Time-dependent density functional theory (TD-DFT) calculation and wavefunction analysis revealed that S₁ and T₁ states of 1 – 3 should be assigned as metal–ligand and ligand–ligand charge-transfer (ML + L'L)CT states. Their UV–Vis. absorption and phosphorescence should be attributed to the charge transfer from the P–Cu–P segment to the 2-PBO ligand. Therefore, as the P–Cu–P angle increased (lower HOMO), the energy of S₁ and T₁ states also increased, following the change of PL color.     

Ruthenium complexes of hexakis(cyanophenyl)[3]radialenes and their di(cyanophenyl)methane precursors: synthesis,photophysical, and electrochemical properties

The coordination chemistry of cross-conjugated ligands and the effect of cross-conjugation on the nature of metal–metal and metal–ligand interactions have received limited attention. To explore the effects of cross-conjugation eight ruthenium complexes were synthesized, mononuclear complexes of two isomeric cross-conjugated [3]radialenes [RuCp(PPh₃)₂(L)]PF₆ and [{RuCp*(dppe)}(L)]PF₆ (L?=?hexakis(4-cyanophenyl)[3]radialene, 2; hexakis(3-cyanophenyl)[3]radialene, 3), and dinuclear complexes [{RuCp(PPh₃)₂}₂(L)](PF₆)₂ and [{RuCp*(dppe)}₂(L)](PF₆)₂ of the diarylmethane precursors (L?=?4,4′-dicyanodiphenylmethane, 4; 3,3′-dicyanodiphenylmethane, 5) to the [3]radialenes. Considerable synthetic challenges allowed only clean isolation of mononuclear complexes of the multidentate radialenes 2 and 3. As expected, coordinating a positively charged metal induces a red shift for the π–π* transition in complexes of ligand 2, but unexpectedly a blue shift for the same transition in complexes of 3 was observed. This points to conformational differences for the [3]radialene in the ruthenium complexes of the para- (2) versus meta- (3) substituted hexaaryl[3]radialenes. Cyclic voltammetry indicates that the methylene spacer in 4 and 5 does not enable any interaction between metal centers and the absorption behavior is essentially as observed for [Ru(NCPh)(PPh₃)₂Cp]PF₆ and [Ru(NCPh)(dppe)Cp*]PF₆ but generally with a slight red shift in absorbance maxima.     

AN N-BONDED Cu(I) THIOCYANATE COMPLEX: ISOTHIOCYANATO-(1,1,1,-TRIS(DIPHENYL-PHOSPHINOMETHYL)ETHANE) COPPER(I)

Abstract

The complex [Cu(((C₆ H₅)₂ PCH₂)₃ CCH₃) (NCS)] has been prepared and characterized by infrared, PMR, and X-ray photoelectron spectroscopy. It has been formulated as a mixture of N- and S-bonded isomers in the solid state, the ratio of the isomers depending on the conditions of isolation of the complex as well as the sampling technique used for the infrared spectral measurements (i.e., mull vs. KBr pellet). In CHCl₃ solution the complex exists exclusively as the N-bonded isomer, although PMR spectroscopy indicates that a rapid exchange of the phosphorus sites of the ligand occurs at room temperature.

The complex [Cu(P(C₆ H₅)₃)₂ SCN]₂, in contrast, is formulated as a dimeric species in the solid state with two bridging thiocyanates. In CHCl₃ solution, however, the bridges cleave to give exclusively the N-bonded monomeric three-coordinate complex.     

含氟菲咯啉的设计合成及其杂配铜配合物的光解水性能

设计合成新型含氟菲咯啉二齿配体,与六氟磷酸四乙腈合铜及磷配体Xantphos进行配位,得到相应的铜基配合物（CP1~CP4）,再以此配合物作为光敏剂用于光催化水解制氢,发现其在均相光解水体系中表现出较好的光敏活性,制氢总转换数（TON）可达896。结合对所选的配合物进行吸收光谱和荧光发射光谱的测试结果可知,此配合物在溶液中也具有很好的稳定性,不会发生配体的重组现象。荧光淬灭实验表明,氧化淬灭为光解水过程中主要的淬灭途径。此外,对这类配合物作为光敏剂的构效关系及其内在机理进行了初步的解释与探讨。     

Photophysical behavior of Ru(II) and Os(II) terpyridyl phenylene vinylene complexes: perturbation of MLCT state by intra-ligand charge-transfer state

The photophysical behavior of novel bimetallic Ru(II) and Os(II) complexes having a bridging ligand consisting of two terpyridyl moieties covalently linked in the 4′ position through a distyrylbenzene bridge (tp vp vpt) is reported. The Ru(II) complex has a unique red emission with an excited state lifetime nearly 2000-times longer than the parent complex, [Ru(mpt)₂](PF6)₂ (mpt=4′-(methylphenyl)-2,2′,6′,2″-terpyridine). Combined spectral data suggest the presence of an emissive intra-ligand charge-transfer (ILCT) state lower in energy than the metal-to-ligand charge transfer (MLCT) state. The Os(II) complex exhibits red emission that is similar to that of the parent complex [Os(mpt)₂](PF₆)₂. However, the excited state absorption spectrum reveals a unique transient absorption in the far red that suggests perturbation of the MLCT state by the ILCT state.     

The synthesis,spectroscopic properties and electrochemistry of (8-quinolinolato)-bis-{1-alkyl-2- (arylazoimidazole)}ruthenium(ii) hexafluorophosphate: single crystal X-ray structure of [ru(q)(meaaime)2](PF6)·CH2Cl2 [Q = 8-quinolinolate,meaaime = 1-methyl-2-( p-tolylazoimidazole)]

The reaction of [Ru(OH₂)₂(RaaiR′)₂]²⁺ [RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R–C₆H₄–N=N–C₃H₂–NN(1)–R′, R=H (1), Me (2), Cl (3); R′ = Me (a), Et (b), CH₂Ph (c)] with 8-quinolinol (HQ) in acetone solution followed by the addition of NH₄PF₆ afforded violet, mixed ligand complexes of composition [Ru(Q)(RaaiR′)₂](PF₆). The structure of [Ru(Q)(MeaaiMe)₂](PF₆) (2a) has been confirmed by X-ray diffraction studies. Solution electronic spectra exhibit a strong MLCT band at 560–580?nm in MeCN. Cyclic voltammogrames show a Ru(III)/Ru(II) couple at 1.0–1.1?V versus SCE along with three successive ligand reductions. The electronic properties are correlated with EHMO results.     

A novel luminescent ionic trinuclear Cu3I2 cluster cuprous complex supported by a P^N ligand: synthesis,structure characterization,properties and TD–DFT calculations

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title ionic trinuclear Cu₃I₂ complex, tris[μ₂‐diphenyl(pyridin‐2‐yl)phosphane‐κ²P:N]di‐μ₃‐iodido‐tricopper(I)(3 Cu—Cu) hexafluoridophosphate, [Cu₃I₂(C₃₉H₃₂NP)₃]PF₆, conventionally abbreviated as [Cu₃I₂(Ph₂PPy)₃]PF₆, is described. Each Cu^I atom is coordinated by two μ₃‐iodide ligands and by a P and an N atom from two Ph₂PPy ligands, giving rise to a CuI₂PN tetrahedral coordination geometry about each Cu^I centre. The electronic absorption and photoluminescence properties of this trinuclear cluster have been studied on as‐synthesized samples, which had been examined previously by powder X‐ray diffraction. A detailed time‐dependent density functional theory (TD–DFT) study was carried out and showed a green emission derived from a halide‐to‐ligand charge transfer and metal‐to‐ligand charge transfer ³(X+M)LCT excited state.     

Hetero‐ and homo‐leptic Ru(II) catalyzed synthesis of cyclic carbonates from CO2; Synthesis,spectroscopic characterization and electrochemical properties

Based on the a ligand BDPPZ [(9a,13a‐dihydro‐4,5,9,14‐tetraaza‐benzo[b]triphenylene‐11‐yl)‐phenyl‐methanone] (1) and its polypyridyl hetero‐ and homoleptic Ru(II) metal complexes, [Ru(bpy)₂L](PF₆)₂ (2), [Ru(phen)₂L](PF₆)₂ (3), [Ru(dafo)₂L](PF₆)₂ (4), [Ru(dcbpy)₂L](PF₆)₂ (5) and [RuL₃](PF₆)₂ (6) (where, L = ligand, bpy = 2,2′‐bipyridine, phen = 1,10‐phenantroline, dafo = 4,5‐diazafluoren‐9‐one and dcbpy = 3,3′‐dicarboxy‐2,2′‐bipyridine), have been synthesized and characterized by elemental analysis, UV–vis, FT‐IR, ¹H and ¹³C‐NMR spectra (for ligand), molar conductivity measurements and X‐ray powder techniques. The electrochemical parameters of the substituted ligand and its polypyridyl hetero‐ and homoleptic Ru(II) metal complexes are reported by cyclic voltammetry. UV–vis spectroscopy is used to compare the differences between the conjugated π systems in this ligand and its Ru(II) metal complexes. The polypyridyl hetero‐ and homoleptic Ru(II) metal complexes also tested as catalysts for the formation of cyclic organic carbonates from carbon dioxide and liquid epoxides which served as both reactant and solvent. The results showed that the [Ru(L)₃](PF₆)₂ (6) complex is more efficient than the other Ru(II) complexes for the formation of cyclic organic carbonates from carbon dioxide. Copyright © 2010 John Wiley & Sons, Ltd.     

Chemical Swarming: Depending on Concentration,an Amphiphilic Ruthenium Polypyridyl Complex Induces Cell Death via Two Different Mechanisms

The crystal structure and in vitro cytotoxicity of the amphiphilic ruthenium complex [ 3 ](PF₆)₂ are reported. Complex [ 3 ](PF₆)₂ contains a Ru?S bond that is stable in the dark in cell‐growing medium, but is photosensitive. Upon blue‐light irradiation, complex [ 3 ](PF₆)₂ releases the cholesterol–thioether ligand 2 and an aqua ruthenium complex [ 1 ](PF₆)₂. Although ligand 2 and complex [ 1 ](PF₆)₂ are by themselves not cytotoxic, complex [ 3 ](PF₆)₂ was unexpectedly found to be as cytotoxic as cisplatin in the dark, that is, with micromolar effective concentrations (EC₅₀), against six human cancer cell lines (A375, A431, A549, MCF‐7, MDA‐MB‐231, and U87MG). Blue‐light irradiation (λ=450 nm, 6.3 J cm^?2) had little influence on the cytotoxicity of [ 3 ](PF₆)₂ after 6 h of incubation time, but it increased the cytotoxicity of the complex by a factor 2 after longer (24 h) incubation. Exploring the unexpected biological activity of [ 3 ](PF₆)₂ in the dark elucidated an as‐yet unknown bifaceted mode of action that depended on concentration, and thus, on the aggregation state of the compound. At low concentration, it acts as a monomer, inserts into the membrane, and can deliver [ 1 ]²⁺ inside the cell upon blue‐light activation. At higher concentrations (>3–5 μm ), complex [ 3 ](PF₆)₂ forms supramolecular aggregates that induce non‐apoptotic cell death by permeabilizing cell membranes and extracting lipids and membrane proteins.