A High Molar Extinction Coefficient Bisterpyridyl Homoleptic Ru(II) Complex with trans-2-Methyl-2-butenoic Acid Functionality: Potential Dye for Dye-Sensitized Solar Cells

In our continued efforts in the synthesis of ruthenium(II) polypyridine complexes as potential dyes for use in varied applications, such as the dye-sensitized solar cells (DSSCs), this work particularly describes the synthesis, absorption spectrum, redox behavior and luminescence properties of a new homoleptic ruthenium(II) complex bearing a simple trans-2-methyl-2-butenoic acid functionality as the anchoring ligand on terpyridine moiety. The functionalized terpyridine ligand: 4'-(trans-2-methyl-2-butenoic acid)-terpyridyl (L1) was synthesized by aryl bromide substitution on terpyridine in a basic reaction condition under palladium carbide catalysis. In particular, the photophysical and redox properties of the complex formulated as: bis-4'-(trans-2-methyl-2-butenoic acid)-terpyridyl ruthenium(II) bis-hexafluorophosphate [Ru(L1)(2)(PF(6))(2)] are significantly better compared to those of [Ru(tpy)(2)](2+) and compare well with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical and redox properties of the complex may be attributed partly to the presence of a substituted α,β-unsaturated carboxylic acid moiety leading to increase in the length of π-conjugation bond thereby enhancing the MLCT-MC (Metal-to-ligand-charge transfer-metal centred) energy gap, and to the reduced difference between the minima of the excited and ground states potential energy surfaces.     

Insights into the mode of action of the anti-Candida activity of 1,10-phenanthroline and its metal chelates

Metal complexes of malonie acid (metal = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I)) were prepared and only the Ag(I) complex inhibited the growth of Candida albicans. Malonate complexes incorporating the chelating 1,10-phenanthroline (1,10-phen) ligand showed a range of activities: good (Mn(II), Cu(II), Ag(I)); moderate (Zn(II)); poor (Co(II), Ni(II)). Metal-free 1,10-phen and Ag(CH(3)CO(2)) were also highly active. The metal-free non-chelating ligands 1,7- phenanthroline and 4,7-phenanthroline were inactive and the Cu(II), Mn(II) and Zn(II) complexs of 1,7-phen displayed only marginal activity. Whereas the Cu(II) malonate/1,10-phen complex induces significant cellular oxidative stress the Zn(II) analogue does not.     

Os(dppe)(dppe monoxide)(CO)Cl2 as an active intermediate in the synthesis of strongly luminescent divalent osmium complexes

Reaction of K₂OsCl₆ with 1,2-bis(diphenylphosphino)ethane (dppe) in 1:2 ratio afforded the osmium(II) Os(dppe)(dppeO)(CO)Cl₂ complex (where dppeO = 1,2-bis(diphenylphosphino)ethane monoxide) with the molecular structure confirmed by X-ray investigations. The Os(dppe)(dppeO)(CO)Cl₂ intermediate can be simply converted to species in reaction with N ∩ N chelating diimines like 1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline or 3,4,7,8-tetramethyl-1,10-phenanthroline. The obtained mixed complexes feature strong (with _em up to 0.57) long lived (with τ_em up to 25.2 μs) MLCT emission.     

含柔性插入配体的钌（Ⅱ）配合物的合成及其与DNA作用研究

设计合成一个柔性插入配体dcpip（dcpip=2-（2,3-环己烯基眯唑并[4,5-f]邻菲咯啉）及其钌（Ⅱ）多吡啶配合物[Ru（bpy）2（dcpip）]（ClO4）2（bpy=2,2＇-联吡啶）和[Ru（phen）2（dcpip）]（ClO4）2（phen=1,10-邻菲咯啉）。采用元素分析和质谱对其进行表征。用电子吸收光谱、荧光光谱和粘度测试研究配合物与DNA作用。研究结果表明,配合物与DNA之间通过插入作用结合。     

三齿吡啶基钌配合物的对位取代基对氢转移催化活性的影响

Three stable 4-substituted pyridine-based ruthenium(II)complexes[RuCl2(PPh3)L](L=4-R-2,6-bis (diethylaminomethylene)pyridine,R=Br,H or allyloxy)were synthesized.The catalytic activities of the complexes toward transfer hydrogenation from alcohols to ketones were investigated.The electronic effects of the para-substituent in the pyridyl ring were probed and we found that the electron-donating group increased the catalytic activity.The result suggests that an electron-donating group is probably preferential for linking the catalytic ruthenium complex and the chemically inert supporting molecules such as a carbosilane dendrimer.     

Fabrication of thin film nanocrystalline TiO2 solar cells using ruthenium complexes with carboxyl and sulfonyl groups

Two ruthenium complexes with carboxyl and sulfonyl groups have been synthesized, [Ru^II(L1)₂(NCS)₂] Ru^IIbis(4,7-diphenyl-1,10-phenanthroline-disulfonic acid disodium salt)-di(thiocyanate) [K313], [Ru^II(L1)₂(dcbpy)] Ru^II bis(4,7-diphenyl-1,10-phenanthroline-disulfonic acid disodium salt)(4,4′-dicarboxy-2,2′-bipyridyl) [K314] as photosensitizers. UV–vis, fluorescence emission, AFM and CV measurements are also supplied for ruthenium complexes. Photovoltaic properties of dye sensitized nanocrystalline semiconductor solar cells based on Ruthenium complexes which bear carboxyl and sunfonyl groups have been tested under standard AM 1.5 sunlight. Under the standard global AM 1.5 solar conditions, K314 and K313-sensitized solar cells demonstrate short circuit photocurrent densities of 14.92 mA/cm² and 11.23 mA/cm² and overall conversion efficiencies of 5.09% and 4.02%, respectively.     

Properties of Binuclear Rhodium(II) Complexes and Their Antibacterial Activity

Binuclear rhodium(II) complexes [Rh(2)Cl(2)(mu-OOCR)(2)(N-N)(2)], [Rh(2)(mu-OOCR)(2)(N-N)(2)(H(2)O)(2)](RCOO)(2) and [Rh(2)Cl(2)(mu-OOCCH(3))(terpy)(2)](H(3)O)Cl(2).9H(2)O (R = H, Me, Bu(n), ph, PhCHOH; N-N = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (dmp) and 6,7-dimethyl-2,3- di(2-pyridyl)quinoxaline (dmpq); terpy 2,2':6',2'-terpyridine) have been synthesized and their structure and properties have been studied by electronic, IR and (1)H NMR spectroscopy. Antibacterial activity of these complexes against Staphylococcus aureus and Escherichia coli has been investigated. The most active antibacterial agents against S. aureus were [Rh(2)(OOCPh)(2)(phen)(2)(H(2)O)(2)](2+), [Rh(2)(OOCPh)(2)(dmpq)(2)(H(2)O)(2)](2+), [Rh(2)(OOCBu)(2)(phen)(2)(H(2)O)(2)](2+) and [Rh(2)-(OOCBu)(2)(bpy)(2)(H(2)O)(2)](2+) which were considerably more active than the appropriate nitrogen ligands. The complexes show rather low activity against E. coli.     

Mixed-ligand platinum and palladium complexes based on dinitrogen chelating ligands and a pyridine bearing the nitronylnitroxide radical

Novel cationic mixed-ligand palladium and platinum complexes based on the chelating ligands 4,7-dimethyl-1,10-phenanthroline and 2,2′-bipyridine with a pyridine bearing the nitronylnitroxide radical are reported. The synthesis, X-ray crystal structures and magnetic properties of the two complexes [Pd(4,7-dimethyl-1,10-phenanthroline)(NIT-pPy)₂](PF₆)₂. DMF and [Pt(2,2′-bipyridine-N,N′)(NIT-pPy)₂](PF₆)₂ · 0.25H₂O, (where NIT-pPy = 2-(p-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) are described. The two metal complexes show a strained square planar geometry. Short intermolecular contacts take place through the nitroxide groups and weak intermolecular antiferromagnetic interactions are dominant at low temperature.     

Synthesis and Biological Activity of Manganese (II) Complexes of Phthalic and Isophthalic Acid: X-Ray Crystal Structures of [Mn(ph)(Phen)(2)(H(2)O)]. 4H(2)O, [Mn(Phen)(2)(H(2)O)(2)](2)(Isoph)(2)(Phen). 12H(2)O and {[Mn(Isoph)(bipy)](4). 2.75biby}(n)(phH(2) = Phthalic Acid; isoph = Isophthalic Acid; phen = 1,10-Phenanthroline; bipy = 2,2-Bipyridine)

Manganese(II) acetate reacts with phthalic acid (phH(2)) to give [Mn(ph)].0.5H(2)O (1). Reaction of 1 with 1,10-phenanthroline produces [Mn(ph)(phen)].2H(2)O (2) and [Mn(ph)(phen)(2)(H(2)O)].4H(2)O (3). Reaction of isophthalic acid (isophH(2)) with manganese(II) acetate results in the formation of [Mn(isoph)].2H(2)O (4). The addition of the N,N-donor ligands 1,10-phenanthroline or 2,2'-bipyridine to 4 leads to the formation of [Mn(2) (isoph)(2)(phen)(3))].4H(2)O (5), [(Mn(phen)(2)(H(2)O)(2)](2)(isoph)(2)(phen).12H(2)O (6) and {[Mn(isoph)(bipy)](4).2.75 biby}(n) (7), respectively. Molecular structures of 3, 6 and 7 were determined crystallographically. In 3 the phthalate ligand is bound to the manganese via just one of its carboxylate groups in a monodentate mode with the remaining coordination sites filled by four phenanthroline nitrogen and one water oxygen atoms. In 6 the isophthalates are uncoordinated with the octahedral manganese center ligated by two phenanthrolines and two waters. In 7 the Isophthalate ligands act as bridges resulting in a polymeric structure. One of the carboxylate groups is chelating a single manganese with the other binding two metal centres in a bridging bidentate mode. The phthalate and isophthalate complexes, the metal free ligands and a number of simple manganes salts were each tested for their ability, to inhibit the growth of Candida albicans. Only the "metal free" 1,10-phenanthroline and its manganese complexes were found to be active.     

Redox behavior of copper(II)/(I) couples with quadridentate ligand: evidence of novel dual gated electron transfer reactions

The reduction reaction of Cu(II)L by decamethylferrocene, where L is quadridentate 1,2-bis(9-methyl-1,10-phenanthrolin-2-yl)ethane, was examined in acetonitrile. We observed parallel gated electron transfer pathways: (1) regulated by the unimolecular deformation within Cu(II)L, and (2) regulated by the bimolecular dimerization to form Cu(II)₂L₂, prior to the electron transfer process with decamethylferrocene.     

Redox chemistry of gold(i) phosphine thiolates: sulfur-based oxidation

The redox chemistry of mononuclear and dinuclear gold(I) phosphine arylthiolate complexes was recently investigated by using electrochemical, chemical, and photochemical techniques. We now report the redox chemistry of dinuclear gold(I) phosphine complexes containing aliphatic dithiolate ligands. These molecules differ from previously studied gold(I) phosphine thiolate complexes in that they are cyclic and contain aliphatic thiolates. Cyclic voltammetry experiments of Au(2) (LL)(pdt) [pdt = propanedithiol; LL = 1,2-bis(diphenylphosphino)-ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,5-bis(diphenylphosphino)pentane (dpppn)] in 0.1 M TBAH/CH(3)CN or CH(2)Cl(2) solutions at 50 to 500 mV/sec using glassy carbon or platinum electrodes, show two irreversible anodic processes at ca. +0.6 and +1.1 V (vs. SCE). Bulk electrolyses at +0.9 V and +1.4 V result in n values of 0.95 and 3.7, respectively. Chemical oxidation of Au(2)(dppp)(pdt) using one equivalent of Br(2) (2 oxidizing equivalents) yields 1,2-dithiolane and Au(2)(dppp)Br(2). The reactivity seen upon mild oxidation /= +1.3 V) is consistent with oxidation of gold(I) to gold(III). Structural and electrochemical differences between gold(I) aromatic and aliphatic thiolate oxidation processes are discussed.     

Synthesis of phenanthroline derivative by Suzuki coupling reaction and the use of its ruthenium complex as an optical pH sensor

A phenanthroline derivative, which has an aniline group, was synthesized by palladium catalyzed Suzuki cross coupling reactions. The aryl phosphine ligand, PPh_3, showed higher activity than the alkyl phosphines, P(^tBu)₃ and PCy_3, in the Suzuki couplings and provided the coupled product, 4-phenyl-7-(4′-amino-biphenyl-4-yl)-[1,10]phenanthroline (5), with 73% yield. Its ruthenium complex, bis(4,7-diphenyl-[1,10]phenanthroline){4-phenyl-7-(4′-amino-biphenyl-4-yl)-[1,10]phenanthroline} ruthenium(II) bis(hexafluorophosphate) (8), was synthesized under mild conditions. This complex showed a linear fluorescence intensity response between pH 3.5 and pH 8.5.     

Copper(II) Complexes Containing Natural Flavonoid Pomiferin Show Considerable In Vitro Cytotoxicity and Anti-inflammatory Effects

A series of new heteroleptic copper(II) complexes of the composition [Cu(L)(bpy)]NO₃·2MeOH (1), [Cu(L)(dimebpy)]NO₃·2H₂O (2), [Cu(L)(phen)]NO₃·2MeOH (3), [Cu(L)(bphen)]NO₃·MeOH (4), [Cu(L)(dppz)]NO₃·MeOH (5) was prepared, where HL = 3-(3,4-dihydroxyphenyl)-5-hydroxy-8,8-dimethyl-6-(3-methylbut-2-ene-1-yl)-4H,8H-benzo[1,2-b:3,4-b′]dipyran-4-one, (pomiferin) and bpy = 2,2′-bipyridine, dimebpy = 4,4′-dimethyl-2,2′-bipyridine, phen = 1,10-phenanthroline, bphen = 4,7-diphenyl-1,10-phenanthroline, and dppz = dipyrido[3,2-a:2′,3′-c]phenazine. The complexes were characterized using elemental analysis, infrared and UV/Vis spectroscopies, mass spectrometry, thermal analysis and conductivity measurements. The in vitro cytotoxicity, screened against eight human cancer cell lines (breast adenocarcinoma (MCF-7), osteosarcoma (HOS), lung adenocarcinoma (A549), prostate adenocarcinoma (PC-3), ovarian carcinoma (A2780), cisplatin-resistant ovarian carcinoma (A2780R), colorectal adenocarcinoma (Caco-2) and monocytic leukemia (THP-1), revealed the complexes as effective antiproliferative agents, with the IC₅₀ values of 2.2–13.0 μM for the best performing complexes 3 and 5. All the complexes 1–5 showed the best activity against the A2780R cells (IC₅₀ = 2.2–6.6 μM), and moreover, the complexes demonstrated relatively low toxicity on healthy human hepatocytes, with IC₅₀ > 100 μM. The complexes were evaluated by the Annexin V/propidium iodide apoptosis assay, induction of cell cycle modifications in A2780 cells, production of reactive oxygen species (ROS), perturbation of mitochondrial membrane potential, inhibition of apoptosis and inflammation-related signaling pathways (NF-κB/AP-1 activity, NF-κB translocation, TNF-α secretion), and tested for nuclease mimicking activity. The obtained results revealed the corresponding complexes to be effective antiproliferative and anti-inflammatory agents.     

Interlocked aromatic species: Crystal structure and Hirshfeld surface analysis of the uranyl ion complex of 3-(pyrimidin-2-yl)benzoate with Ni(phen)32 + counter-ions

The reaction of uranyl nitrate with 3-(pyrimidin-2-yl)benzoic acid (LH) in the presence of nickel(II) nitrate and 1,10-phenanthroline (phen) yields the complex [Ni(phen)₃][UO₂(L)₃]₂·2.5H₂O (1), in which the uranium atom is chelated by three carboxylate groups. Analysis of short intermolecular contacts shows that those associated with π⋯π interactions do not show up prominently, notwithstanding the number of aromatic rings present, and the packing mode appears to be primarily a result of Coulombic interactions and best shape fitting.     

Household LED irradiation under air: cationic polymerization using iridium or ruthenium complex photocatalysts

Household LED bulbs are used to promote the ring-opening photopolymerization of epoxides in the presence of a photocatalyst (here tris(2-phenylpyridine)iridium [Ir(ppy)₃] or tris(1,10-phenanthroline)ruthenium(II) [Ru(phen)₃²⁺] complex) and a silyl radical source. Remarkably, even under this very soft irradiation (light intensity lower than 10 mW/cm2), excellent polymerization profiles are obtained i.e., this is the first reported use of such very convenient irradiation devices for photopolymerization processes. The role of the silane and other hydrogen donors is outlined.     

The effect of pH on the emission and absorption spectra of a ruthenium complex

A ruthenium complex, Ru(Phen)₂(Phen-OH-CO₂Et)²⁺(PF₆)₂, where Phen=1,10-phenanthroline and Phen-OH-CO₂Et=3-carbethoxy,4-hydroxy-1,10-phenanthroline ligands has been synthesized. The emission intensity of this complex changes in the pH range of 3–11, which makes it useful in the design of chemosensors.     

Redox and catalytic properties of new polypyrrole modified electrodes functionalized by [Ru(bpea)(bpy)H2O] complexes; bpea=N,N′-bis(2-pyridylmethyl)ethylamine, bpy=2,2′-bipyridine

New ruthenium(II) complexes containing one or two pyrrole-functionalized polypyridylic ligands have been prepared in order to study their electrochemical behaviour in heterogeneous phase, after anodic polymerization from CH₂Cl₂ solution on an electrode surface. Complexes containing one pyrrole unit have general formula [Ru(bpea-pyr)(bpy)(L)]²⁺ (bpea-pyr=N-[3-bis(2-pyridylmethyl)aminopropyl]pyrrole, bpy=2,2′-bipyridine, L=Cl, complex 3, or L=H₂O, complex 1), whereas compounds having two pyrrole units correspond to [Ru(bpea-pyr)(bpy-pyr)(L)]²⁺ (bpy-pyr=4-methyl-4′-pyrrolylbutyl-2,2′-bipyridine, L=Cl, complex 4, or L=H₂O, complex 2). Upon oxidative polymerization, all complexes form highly stable polypyrrolic films on a graphite disk electrode surface. An electrode modified with complex 2 polypyrrole coating film, C/poly-2, has been tested as heterogeneous catalyst for the oxidation of benzyl alcohol, showing a remarkably high efficiency and notably improving the results obtained with analogous complexes in homogeneous phase.     

Transition metal-complexed catenanes and rotaxanes in motion: Towards molecular machines

In the course of the last decade, many dynamic molecular systems, for which the movements are controlled from the outside, have been elaborated. These compounds are generally referred to as “molecular machines”. Transition metal-containing catenanes and rotaxanes are ideally suited to build such systems. In the present review article, we will discuss a few examples of molecular machines elaborated and studied in Strasbourg. In the first section we will discuss an electrochemically driven system, consisting of a fast-moving pirouetting rotaxane. The second paragraph will be devoted to a linear rotaxane dimer whose behaviour is reminiscent of muscles, in the sense that it can be stretched or contracted, and in the rest of this review article, we will mostly focus on light-driven machines, consisting of ruthenium(II)-complexed rotaxanes or catenanes. For these latter systems, the synthetic approach is based on the template effect of an octahedral ruthenium(II) centre. Two 1,10-phenanthroline ligands are incorporated in an axis or in a ring, affording the precursor to the rotaxane or the catenane, respectively. complexes display the universally used ³MLCT (metal-to-ligand charge transfer) excited state and another interesting excited state, the ³LF (ligand field) state, which is strongly dissociative. By taking advantage of this latter state, it has been possible to propose a new family of molecular machines, which are set in motion by populating the dissociative ³LF state, thus leading to ligand exchange in the coordination sphere of the ruthenium(II) centre. Finally, the potential of the Ru(terpy)(phen) core in the frame of light-driven molecular machines will be briefly discussed.     

Synthesis and applications of 3,6-carbazole-based conjugated side-chain copolymers containing complexes of 1,10-phenanthroline with Zn(II), Cd(II) and Ni(II) for dye-sensitized solar cells

Three novel donor-acceptor polymeric metal complexes based on polycarbazole containing complexes of 1,10-phenanthroline with Zn(II), Cd(II) and Ni(II) have been synthesized by the Ullmann reaction and characterized by gel permeation chromatography, FT-IR, UV-visible absorption and photoluminescence spectroscopy, cyclic voltammetry and elemental analysis. The application of these organometallic polymers in fabricated dye-sensitized solar cells has been studied. The solar cells exhibited good device performance with a power conversion efficiency of up to 0.44%, under simulated air mass 1.5 G solar irradiation.     

Synthesis,structure, and properties of two novel copper(II) complexes, [Cu(phen)(L)2]·6H2O and [Cu(phen)3]·(ClO4)2

Two novel copper(II) complexes, namely [Cu(phen)(L)₂]·6H₂O (1) and [Cu(phen)₃]·(ClO₄)₂ (2) have been synthesized under mild condition (HL = 5-methyl-1H-pyrazole-3-carboxylic acid, phen = 1,10-phenanthroline). We report the structural evidence of discrete water decamer conformation in the solid state. These units are found to act as supramolecular glue in the aggregation of mononuclear copper(II) complex to give a three-dimensional network through hydrogen-bonding. The preliminary investigation on the thermal behavior and the anion exchange property of the complexes are presented.