4-Bromo-,'-di-phenyl-benzimidamide '-oxide.

The title compound, CHBrNO, crystallizes with two similar mol-ecules in the asymmetric unit. The extended structure features dimers linked by pairs of N-H⋯O and C-H⋯O hydrogen bonds. The HNCNO moiety of the title compound shows delocalization over the N-C-N part, as evidenced by the similar C-N bond distances.

Spectro-electrochemical study of iron and ruthenium bis-terpyridine complexes with methyl viologen-like subunits as models for supramolecular polymers.

Metallo-supramolecular polyelectrolytes (MEPE) have a variety of attractive properties concerning electrochromism, spin-crossover, rheology, and cell differentiation. Previous studies suggest that these polynuclear structures can be regarded as an assembly of individual subunits and mononuclear complexes can act as models. In this study, we synthesize a monotopic and a ditopic terpyridine ligand with pyridinium units as well as the corresponding iron and ruthenium MEPEs and their mononuclear counterparts.

Pt(II)-bis(quinolinyl) complexes for photocatalytic hydrogen production.

Three Pt(II)-bis(quinolinyl) complexes with varying electron densities were synthesized, structurally characterized and used for photocatalytic hydrogen production under different conditions. All the complexes were found to be active for hydrogen production giving a maximum turnover number (TON) of 1230 surpassing the conventionally used Pt-terpyridyl complexes.

Red Absorbing Cyclometalated Ir(III) Diimine Photosensitizers Competent for Hydrogen Photocatalysis.

Two new cyclometalated Ir(III) diimine complexes were used as photosensitizers for homogeneous hydrogen evolution reaction (HER). These complexes were characterized by electrochemistry, ultraviolet-visible absorption, time-resolved and steady-state photoluminescence spectroscopy as well as by theoretical methods. The metal-ligand-to-ligand charge transfer character of their lowest excited state was shown to be competent for efficient H photoproduction in the presence of [Co(dmgH)(py)Cl] as the hydrogen evolution catalyst, triethanolamine as the sacrificial electron donor, and HBF as the proton source.

Active repair of a dinuclear photocatalyst for visible-light-driven hydrogen production.

The molecular apparatus behind biological photosynthesis retains its long-term functionality through enzymatic repair. However, bioinspired molecular devices designed for artificial photosynthesis, consisting of a photocentre, a bridging ligand and a catalytic centre, can become unstable and break down when their individual modules are structurally compromised, halting their overall functionality and operation. Here we report the active repair of such an artificial photosynthetic molecular device, leading to complete recovery of catalytic activity.

Dinuclear 2,4-di(pyridin-2-yl)-pyrimidine based ruthenium photosensitizers for hydrogen photo-evolution under red light.

In this study, we report two dinuclear Ru(II) complexes C1 and C2 and compare them to their mononuclear analogues Ref1 and Ref2. The dinuclear species exhibit a much stronger absorption, longer excited-state lifetimes and higher luminescence quantum yields than the mononuclear complexes. In addition, C1 and C2 are easier to reduce.

Two Ru Linkage Isomers with Distinctly Different Charge Transfer Photophysics.

The ligand PHEHAT (PHEHAT = 1,10-phenanthrolino[5,6-]1,4,5,8,9,12-hexaazatriphenylene) presents a structural asymmetry that has a dramatic influence on the photophysical properties depending on the chelation site of the metal ion in the linkage isomers. While [Ru(phen)HATPHE] behaves classically, like [Ru(bpy)], [Ru(phen)PHEHAT] exhibits an unusual behavior. It appears that this complex has two MLCT bright states, the lower one being weakly emissive or nonemissive depending on the solvent and temperature.

,'-Bis[2,6-bis-(1-methyl-eth-yl)phen-yl]pyridine-4-carboximidamide toluene hemisolvate.

The title compound, CHN·0.5CH, is a symmetrically ,'-disubstituted aryl-amidine containing a 4-pyridyl substituent on the carbon atom of the N-C-N linkage and bulky 2,6-diiso-propyl-phenyl groups on the nitro-gen atoms. It crystallizes in the configuration and its amidine C-N bonds present amine [1.

Preoperative imaging of deep endometriosis: pitfalls of a diagnostic test before surgery.

The usefulness of a test is determined by the clinical interpretation of its sensitivity and specificity. The pitfalls of a test with a surgical endpoint are described in this article, taking the diagnosis of deep endometriosis by imaging as an example, without discussing the management of deep endometriosis. Laparoscopy is not a 100% accurate "gold standard".

In-Depth Study of the Electronic Properties of NIR-Emissive κN Terpyridine Rhenium(I) Dicarbonyl Complexes.

The structure-properties relationship in a series of carbonyl rhenium(I) complexes based on substituted terpyridine ligands of general formula [Re(κN-Rtpy)(CO)L] is explored by both experimental and theoretical methods. In these compounds, the terpyridine ligands adopt both bidentate (κN) and terdentate (κN) coordination modes associated with three or two carbonyls, respectively. Conversion from the κN to the κN coordination mode leads to large changes in the absorption spectra and oxidation potentials due to destabilization of the HOMO level of each complex.

Substituted 2,4-Di(pyridin-2-yl)pyrimidine-Based Ruthenium Photosensitizers for Hydrogen Photoevolution under Red Light.

The photocatalytic reduction of water to form hydrogen gas (H) is a promising approach to collect, convert, and store solar energy. Typically, ruthenium tris(bipyridine) and its many derivatives are used as photosensitizers (PSs) in a variety of photocatalytic conditions. The bis(terpyridine) analogues, however, have only recently gained attention for this application because of their poor photophysical properties.

Controlling photocatalytic reduction of CO in Ru(II)/Re(I) dyads linker oxidation state.

Electronic communication between the linked metal centers in Ru(ii)-Re(i) dyads is tuned using the oxidation state (S and SO2) of sulfur-bridged ligands. Higher catalytic activity is seen for the SO2-bridged dyad in the photocatalytic reduction of CO2.

Heteroleptic ruthenium bis-terpyridine complexes bearing a 4-(dimethylamino)phenyl donor and free coordination sites for hydrogen photo-evolution.

Motivated by the recent report of a heteroleptic ruthenium bis-terpyridine complex [Ru(toltpy)(bipytpy)](PF6)2 (toltpy: 4'-(tolyl)-2,2':6',2''-terpyridine; bipytpy: 4'-(4-bromophenyl)-4,4''':4'',4''''-di-pyridinyl-2,2':6',2''-terpyridine) capable of driving the photo-evolution of hydrogen with a constant rate of activity for 12 days [M. Rupp et al., Inorg.

Mimicking 2,2':6',2'':6'',2'''-quaterpyridine complexes for the light-driven hydrogen evolution reaction: synthesis, structural, thermal and physicochemical characterizations.

The synthetic difficulties associated with quaterpyridine (qtpy) complexes have limited their use in the formation of various metallosupramolecular architectures in spite of their diverse structural and physicochemical properties. Providing a new facile synthetic route to the synthesis of functionalised qtpy mimics, we herein report the synthesis of three novel -NH functionalized qtpy-like complexes 12-14 with the general formula M(CHN)(NO) (M = Co(ii), Ni(ii) and Cu(ii)) in high yield and purity. Characterization of these complexes has been done by single crystal X-ray diffraction (SCXRD), thermogravimetric analysis, UV-Vis, infrared, mass spectrometry and cyclic voltammetry.

Design and photophysical studies of iridium(iii)-cobalt(iii) dyads and their application for dihydrogen photo-evolution.

We report several new dyads constituted of cationic iridium(iii) photosensitizers and cobalt(iii) catalyst connected via free pendant pyridine on the photosensitizers. These dyads were studied by X-ray crystallography, electrochemistry, absorption and emission spectroscopy as well as theoretical calculations and were shown to efficiently produce H2 under visible light irradiation. In every case, the dyad outperformed the equivalent system without a pendant pyridine.

Photocatalytic Hydrogen Evolution Driven by a Heteroleptic Ruthenium(II) Bis(terpyridine) Complex.

Since the initial report by Lehn et al. in 1979, ruthenium tris(bipyridine) ([Ru(bpy)]) and its numerous derivatives were applied as photosensitizers (PSs) in a large panel of photocatalytic conditions while the bis(terpyridine) analogues were disregarded because of their low quantum yields and short excited-state lifetimes. In this study, we prepared a new terpyridine ligand, 4'-(4-bromophenyl)-4,4‴:4″,4‴'-dipyridinyl- 2,2':6',2″-terpyridine (Bipytpy) and used it to prepare the heteroleptic complex [Ru(Tolyltpy)(Bipytpy)](PF) (; Tolyltpy = 4'-tolyl-2,2':6',2'-terpyridine).

A nano-junction of self-assembled mixed-metal-centre molecular wires on transparent conductive oxides.

The fabrication of stable, highly conductive molecular nano-junctions is one of the main research goals in the field of molecular electronics. In this paper we report on the self-assembly and functional characterisation of highly conductive molecular wires, based on mixed-metal polynuclear complexes, at the surface of a transparent conductive oxide. The adopted synthetic approach involves metal-coordination reactions on oxide surfaces, pre-functionalised with a monolayer of terpyridine moieties that are used as anchoring sites for the integration of ditopic, redox-active ruthenium-bisterpyridine molecules through iron(ii) centres.

Ultrafast charge transfer excited state dynamics in trifluoromethyl-substituted iridium(iii) complexes.

Time-resolved spectroscopy was exploited to gain new insights into the nature and dynamics of charge transfer excited states of bis-cyclometalated Ir(iii) complexes. We showed that its dynamics is strongly influenced by the nature of the diimine ligand due to the existence of a ligand-ligand charge transfer process in the picosecond timescale. All the results are supported by DFT/TD-DFT calculations and spectroelectrochemistry.

Alkyl chain length effects on double-deck assembly at a liquid/solid interface.

Controlled double-deck packing is an appealing means to expand upon conventional 2D self-assembly which is critical in crystal engineering, yet it is rare and poorly understood. Herein, we report the first systematic study of double-deck assembly in a series of alkylated aminoquinone derivatives at the liquid-solid interface. The competition between the fraction of alkyl chains adsorbed on the surface and the optimal conformation of the alkyl chains near the head group leads to a stepwise structural transformation ranging from complete double-deck packing to complete monolayer packing.

Probing the effect of β-triketonates in visible and NIR emitting lanthanoid complexes.

An isomorphous series of lanthanoid complexes containing tribenzoylmethanide (tbm) and 1,10-phenanthroline (phen) ligands has been synthesised and structurally characterised. These complexes, formulated as [Ln(phen)(tbm)3] (Ln = Eu3+, Er3+ and Yb3+), were compared with analogous dibenzoylmethanide (dbm) [Ln(phen)(dbm)3] complexes to investigate the effect of changing β-diketonate to β-triketonate ligands on the photophysical properties of the complex. The photophysical properties for the Eu3+ complexes were similar for both systems, whereas a modest enhancement was observed for Yb3+ and Er3+ moving from the dbm to the tbm complexes.

Modular Cavities: Induced Fit of Polar and Apolar Guests into Halogen-Based Receptors.

Neutral triangular macrocyclic compounds, [PdX(4,7-phen)]·(DMF)·EtO (X = Cl, Br; 4,7-phen = 4,7-phenanthroline; DMF = N, N'-dimethylformamide; EtO = diethyl ether), were synthesized, and their molecular structures were characterized. Solution-state H NMR results suggested the formation of metal-ligand bonds, and single-crystal X-ray crystallography revealed clear triangular structures. A detailed examination of the structures indicated the formation of two kinds of cavities in the solid state, where a triangular unit works as a halogen-based receptor for polar and apolar solvents through weak hydrogen-bonding and dipole-dipole interaction.

Blue-Emissive Cobalt(III) Complexes and Their Use in the Photocatalytic Trifluoromethylation of Polycyclic Aromatic Hydrocarbons.

Room-temperature luminescent Co complexes (1 and 2) are presented that exhibit intense ligand-to-metal and ligand-to-ligand charge transfer absorption in the low-energy UV region (λ ≈360-400 nm) and low-negative quasi-reversible reduction events (E =-0.58 V and -0.39 V vs.

A Smorgasbord of 17 Cobalt Complexes Active for Photocatalytic Hydrogen Evolution.

Seventeen cobalt complexes-eleven dinuclear cobalt(II) complexes and three tetranuclear cobalt complexes (two mixed valent) of ditopic ligands, with varying N-donor aromatic bridging moieties and pendant pyridine side arms, as well as three mononuclear cobalt(II) complexes of Schiff base macrocyclic ligands-have been screened for photocatalytic hydrogen evolution reaction (HER) activity. All 17 complexes are active catalysts for the HER, in both DMF and aqueous solution, in tandem with the [Ru(bpy) ] (bpy=2,2'-bipyridine) photosensitiser. All are benchmarked to the literature standard [Co (dmgH) (py)Cl] (dmg=dimethylglyoxime, py=pyridine) under identical conditions.

Unusual Photooxidation of S-Bonded Mercaptopyridine in a Mixed Ligand Ruthenium(II) Complex with Terpyridine and Bipyridine Ligands.

An unusual photooxidation of a coordinated 4-mercaptopyridine ( SpyH) ligand in the [Ru(Hmctpy)(dmbpy)(κ S-SpyH)]complex (Hmctpy = 4'-carboxy-2,2';6',2″-terpyridine, dmbpy = 4,4'-dimethyl-2,2'-bipyridine) takes place under visible and UV irradiation, in aerated acetonitrile. The [Ru(mctpy)(dmbpy)(κ S-SOpy)] sulfinato product has been characterized by a variety of methods, including X-ray diffraction which supports the presence of the Ru-κ S-SpyH isomer in the starting complex. The photooxidation of the 4-mercaptopyridine ligand enhances the back-bonding interactions in the complex by means of the strongly acceptor 4-pyridinesulfinato-SOpy species, increasing the redox potential of the Ru(III)/Ru(II) couple significantly from 1.

Converging Energy Transfer in Polynuclear Ru(II) Multiterpyridine Complexes: Significant Enhancement of Luminescent Properties.

Ruthenium-based complexes are widely used as photocatalysts, as photosensitizers, or as building blocks for supramolecular assemblies. In the field of solar energy conversion, building light harvesting antenna is of prime interest. Nevertheless, collecting light is mandatory but not sufficient; once collected and transferred, the exciton has to be long-lived enough to be transferred to a catalytic site.