Photo-release of acetonitrile in ruthenium(II) complexes with various substituted terpyridine ligands.

The photo-release of acetonitrile is investigated in a series of ruthenium(II) complexes of the general formula [Ru(R-phtpy)(acac)(MeCN)](PF) (phtpy stands for 4'-phenyl-2,2':6',2''-terpyridine, and R = EtN, MeN, MeO, Me, H, NO). The experimental quantum yields of photo-release ( = MeCN released/photons absorbed) increases with the donating capability of R, with values ranging from = 0 (NO) to = 0.05 (EtN).

Ruthenium nitrosyl complexes with NO release capability: the use of fluorene as an antenna.

A ruthenium nitrosyl complex of formula [Ru(fluorene(C6)CHO-terpy)(bipy)(NO)] (AC) in which fluorene(C6) is the 9,9-dihexylfluorene, terpy the 2,2';6',2''-terpyridine, and bipy the 2,2'-bipyridine is presented with its related [Ru(MeO-terpy)(bipy)(NO)] (C) and 9,9-dihexylfluorene 2-hydroxymethylfluorene (A) building blocks. The reference complex C undergoes NO release capabilities under irradiation at = 365 nm. The effect of the introduction of the fluorescent A antenna within the resulting AC complex is discussed both experimentally and theoretically.

Photorelease of Nitric Oxide (NO) in Mono- and Bimetallic Ruthenium Nitrosyl Complexes: A Photokinetic Investigation with a Two-Step Model.

Two monometallic and three bimetallic ruthenium acetonitrile (RuMeCN) complexes are presented and fully characterized. All of them are built from the same skeleton [FTRu(bpy)(MeCN)], in which FT is a fluorenyl-substituted terpyridine ligand and bpy is the 2,2'-bipyridine. The crystal structure of [FTRu(bpy)(MeCN)](PF) is presented.

A Trojan horse approach for enhancing the cellular uptake of a ruthenium nitrosyl complex.

Ruthenium nitrosyl (RuNO) complexes continue to attract significant research interest due to several appealing features that make these photoactivatable nitric oxide (NO˙) donors attractive for applications in photoactivated chemotherapy. Interesting examples of molecular candidates capable of delivering cytotoxic concentrations of NO˙ in aqueous media have been discussed. Nevertheless, the question of whether most of these highly polar and relatively large molecules are efficiently incorporated by cells remains largely unanswered.

Acetylacetonate Ruthenium Nitrosyls: A Gateway to Nitric Oxide Release in Water under Near-Infrared Excitation by Two-Photon Absorption.

A fundamental challenge for phototriggered therapies is to obtain robust molecular frameworks that can withstand biological media. Photoactivatable nitric oxide (NO) releasing molecules (photoNORMs) based on ruthenium nitrosyl (RuNO) complexes are among the most studied systems due to several appealing features that make them attractive for therapeutic applications. Nevertheless, the propensity of the NO ligand to be attacked by nucleophiles frequently manifests as significant instability in water for this class of photoNORMs.

Two-photon absorption-based delivery of nitric oxide from ruthenium nitrosyl complexes.

Since the discovery of the numerous physiological roles exhibited by nitric oxide (NO), ruthenium nitrosyl (RuNO) complexes have been regarded as one of the most promising NO donors, stable, well tolerated by the body and capable of releasing NO locally and quantitatively, under light irradiation. This release can be achieved by two-photon absorption (TPA) processes, which allow the irradiation to be performed in the near infrared domain, where light has its maximum depth of penetration in biological tissues. This review provides a short introduction on the biological properties of NO, on RuNO complexes with photo-releasing capabilities, and on the origin of TPA properties in molecules.

Crystal structure of 1,1'-(pyridine-2,6-di-yl)bis-[-(pyridin-2-ylmeth-yl)methanaminium] dichloride dihydrate.

In the title compound, CHN ·2Cl·2HO, the two pyridine side arms are not coplanar, with the terminal pyridine rings subtending a dihedral angle of 26.45 (6)°. In the crystal, hydrogen bonds, inter-molecular C-H⋯Cl contacts and a weak C-H⋯O inter-action connect the mol-ecule with neighbouring chloride counter-anions and lattice water mol-ecules.

Two-Photon-Triggered NO Release via a Ruthenium-Nitrosyl Complex with a Star-Shaped Architecture.

We report herein a molecular engineering strategy based on the design of a multipolar ruthenium-nitrosyl (Ru-NO) complex with a three-branched architecture. The three Ru-NO units are introduced at the periphery of a highly π-delocalized truxene core bearing three terpyridine ligands. The two-photon absorption capabilities of the complex were investigated by the Z-scan technique.

Multistep Photochemical Reactions of Polypyridine-Based Ruthenium Nitrosyl Complexes in Dimethylsulfoxide.

The photorelease of nitric oxide (NO·) has been investigated in dimethylsulfoxide (DMSO) on two compounds of formula [Ru(R-tpy)(bpy)(NO)](PF), in which bpy stands for 2,2'-bipyridine and R-tpy for the 4'--2,2':6',2″-terpyridine with R = H and MeOPh. It is observed that both complexes are extremely sensitive to traces of water, leading to an equilibrium between [Ru(NO)] and [Ru(NO)]. The photoproducts of formula [Ru(R-tpy)(bpy)(DMSO)](PF) are further subjected to a photoreaction leading to a reversible linkage isomerization between the stable Ru-DMSO (sulfur linked) and the metastable Ru-DMSO (oxygen linked) species.

Chemical and photochemical behavior of ruthenium nitrosyl complexes with terpyridine ligands in aqueous media.

The synthesis and behavior in water of a set of various cis(Cl,Cl)-[R-tpyRuCl(NO)](PF) and trans(Cl,Cl)-[R-tpyRuCl(NO)](PF) (R = fluorenyl, phenyl, thiophenyl; tpy = 2,2':6',2''-terpyridine) complexes are presented. In any case, one chlorido ligand is substituted by a hydroxo ligand and the final species arises as a single trans(NO,OH) isomer, whatever the nature of the starting cis/trans(Cl,Cl) complexes. Six X-ray crystal structures are presented for cis(Cl,Cl)-[thiophenyl-tpyRuCl(NO)](PF) (cis-3a), trans(Cl,Cl)-[thiophenyl-tpyRuCl(NO)](PF) (trans-3a), trans(NO,OH)-[phenyl-tpyRu(Cl)(OH)(NO)](PF) (4a), trans(NO,OH)-[thiophenyl-tpyRu(Cl)(OH)(NO)](PF) (4b), trans(NO,OEt)-[phenyl-tpyRu(Cl)(OEt)(NO)](PF) (5a), and trans(NO,OH)-[phenyl-tpyRu(Cl)(OEt)(NO)](PF) (5b) compounds.

Author Correction: Effect of trans(NO, OH)-[RuFT(Cl)(OH)NO](PF) ruthenium nitrosyl complex on methicillin-resistant Staphylococcus epidermidis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Effect of trans(NO, OH)-[RuFT(Cl)(OH)NO](PF) ruthenium nitrosyl complex on methicillin-resistant Staphylococcus epidermidis.

Antibiotic resistance is becoming a global scourge with 700,000 deaths each year and could cause up to 10 million deaths by 2050. As an example, Staphylococcus epidermidis has emerged as a causative agent of infections often associated with implanted medical devices. S.

trans- and cis-(Cl,Cl)-[Ru(FT)Cl(NO)](PF): promising candidates for NO release in the NIR region.

cis- and trans-(Cl,Cl)-[Ru(FT)Cl(NO)](PF) complexes show efficient NO photodelivery upon two-photon excitation in the NIR region. Moreover, cytotoxicity and phototoxicity studies provide evidence that these complexes are promising candidates as photoactivatable molecular tools for resection of malignancies.

Two-Step Photon Absorption Driving the Chemical Reaction in the Model Ruthenium Nitrosyl System [Ru(py)4Cl(NO)](PF6)2·(1)/2H2O.

Various systems containing the [ML5NO] molecule, where M = Fe, Ru, ...

Establishing the Two-Photon Linkage Isomerization Mechanism in the Nitrosyl Complex trans-[RuCl(NO)(py)4](2+) by DFT and TDDFT.

The density functional theory calculations presented in this work allow the first rationalization of the full linkage photoisomerization mechanism of trans-[RuCl(NO)(py)4](2+), in both the forward and reverse directions. These mechanisms are consistent with the experimental data establishing that blue-light irradiation triggers the forward process, while red or IR photons trigger the reverse process. Characterization of the singlet and lowest triplet potential energy surfaces shows that, despite the unfavorable thermodynamic character of the forward process, the topologies of the surfaces and particularly some crucial surface crossings enable the isomerization.

Comparative photo-release of nitric oxide from isomers of substituted terpyridinenitrosylruthenium(II) complexes: experimental and computational investigations.

The 4'-(2-fluorenyl)-2,2':6',2''-terpyridine (FT) ligand and its cis(Cl,Cl)- and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) complexes have been synthesized. Both isomers were separated by HPLC and fully characterized by (1)H and (13)C NMR. The X-ray diffraction crystal structures were solved for FT (Pna21 space group, a = 34.

Structural influence on the photochromic response of a series of ruthenium mononitrosyl complexes.

In mononitrosyl complexes of transition metals two long-lived metastable states corresponding to linkage isomers of the nitrosyl ligand can be induced by irradiation with appropriate wavelengths. Upon irradiation, the N-bound nitrosyl ligand (ground state, GS) turns into two different conformations: isonitrosyl O bound for the metastable state 1 (MS1) and a side-on nitrosyl conformation for the metastable state 2 (MS2). Structural and spectroscopic investigations on [RuCl(NO)py(4)](PF(6))(2)·1/2H(2)O (py = pyridine) reveal a nearly 100% conversion from GS to MS1.

The three-dimensional intermolecular network formed via water molecules in trans-bis(nitrito-κN)tetrakis(pyridine-κN)ruthenium(II) dihydrate.

The molecular geometry of the tetragonal crystal structure of the title compound, [Ru(NO(2))(2)(C(5)H(5)N)(4)]·2H(2)O, differs from that previously determined by powder diffraction [Schaniel et al. (2010). Phys.

A facile route for the preparation of nanoparticles of the spin-crossover complex [Fe(Htrz)2(trz)](BF4) in xerogel transparent composite films.

Films and monoliths containing the spin crossover complex [Fe(Htrz)(2)(trz)](BF(4)) (trz = 1,2,4-triazole) as nanoparticles have been obtained. The dispersion and consecutive inclusion of the Fe complex in a silica matrix prepared from tetramethoxysilane or tetraethoxysilane afford monoliths or films with a violet colour at room temperature, which turns white above 380 K. This change of colour is reversible.

[Ru(py)4Cl(NO)](PF6)2.0.5H2O: a model system for structural determination and ab initio calculations of photo-induced linkage NO isomers.

Structure analysis of ground state (GS) and two light-induced (SI and SII) metastable linkage NO isomers of [Ru(py)4Cl(NO)](PF6)2.0.5H2O is presented.

Electrical conductivity and spin crossover: a new achievement with a metal bis dithiolene complex.

Three new compounds based on the cationic complex [Fe(III)(3-R-salEen)(2)]+ (salEen stands for N-(2-ethylamino)ethyl)-salicylaldimine, R = H, CH(3)O) with the electroactive Ni(dmit)(2) species as a counterion (dmit stands for 1,3-dithia-2-thione-4,5-dithiolato) have been synthesized and structurally and magnetically characterized. Compound 1 ([Ni(dmit)(2)][Fe(3-OMe-salEen)(2)]. CH(3)OH) shows an apparent hysteresis loop, due to an irreversible desolvatation process.

Photogeneration of two metastable NO linkage isomers with high populations of up to 76% in trans-[RuCl(py)4(NO)][PF6]2.1/2H2O.

Two light-induced metastable NO linkage isomers with oxygen-bound (SI) and side-on configuration (SII) of NO are generated in trans-[RuCl(py)(4)(NO)][PF(6)](2).(1/2)H(2)O. Irradiation by light in the blue-green spectral range (450-530 nm) leads to the population of SI.

Metallic polycrystalline thin films of the single-component neutral molecular solid Ni(tmdt)2.

Metallic thin films of the single-component, neutral, molecular solid Ni(tmdt)2 have been prepared by electrocrystallization on passivated silicon substrates. Metallicity is achieved down to 6 K despite the polycrystalline morphology.

(BETS)2[Fe(tdas)2]2: a new metal in the molecular conductor family.

The structure of bis[4,5-ethylenedithio-2-(4,5-ethylenedithio-1,3-diselenacyclopent-4-en-2-ylidene)-1,3-diselenacyclopent-4-enium] bis(mu-1,2,5-thiadiazole-3,4-dithiolato-kappa3S4,S5:S4)bis[(1,2,5-thiadiazole-3,4-dithiolato-kappa2S4,S5)iron(III)], (BETS)(2)[Fe(tdas)(2)](2) [BETS is alternatively called bis(ethylenedithio)tetraselenafulvalenium] or (C(10)H(8)S(4)Se(4))(2)[(Fe(C(2)N(2)S(3))(2))(2)], consists of segregated columns of dimers of BETS and columns of dimers of [Fe(tdas)(2)]. Each dimer displays inversion symmetry. Numerous chalcogen-chalcogen contacts are observed within and between the columns, producing a network of interactions responsible for the metal-like behaviour of the compound.