Structure, chemical and photochemical reactivity and biological activity of some ruthenium amine nitrosyl complexes
TL;DR: In this article, the site of the reduction [Ru(NO)]3++e−→[Ru( NO)]2+ was assigned to the NO ligand based on molecular orbital (MO) analysis and on reduction product analysis.
About: This article is published in Coordination Chemistry Reviews.The article was published on 2003-01-01. It has received 275 citations till now. The article focuses on the topics: Linkage isomerism & Trans effect.
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657 citations
TL;DR: Although some ruthenium nitrosyls are stable under physiological conditions and are capable to NO delivery to proteins such as myoglobin and cytochrome c oxidase, so far success has been limited in using these nitroSyls as light-activated NO donors in cellular and tissue models.
284 citations
TL;DR: The research has shown that alteration of the ligands, in terms of donor atoms, extent of conjugation, and substituents on the ligand frames, sensitizes the final ruthenium nitrosyls toward visible light in a predictable fashion, and TDDFT calculations provide insight into the mechanisms of sensitization by this technique.
Abstract: Nitric oxide (NO) can induce apoptosis (programmed cell death) at micromolar or higher doses. Although cell death via NO-induced apoptosis has been studied quite extensively, the targeted delivery of such doses of NO to infected or malignant tissues has not been achieved. The primary obstacle is indiscriminate NO release from typical systemic donors such as glycerin trinitrate: once administered, the drug travels throughout the body, and NO is released through a variety of enzymatic, redox, and pH-dependent pathways.Photosensitive NO donors have the ability to surmount this difficulty through the use of light as a localized stimulus for NO delivery. The potential of the method has prompted synthetic research efforts toward new NO donors for use as photopharmaceuticals in the treatment of infections and malignancies. Over the past few years, we have designed and synthesized several metal nitrosyls (NO complexes of metals) that rapidly release NO when exposed to low-power (milliwatt or greater) light of var...
277 citations
TL;DR: This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide).
Abstract: Photoactivatable (alternatively, photoremovable, photoreleasable, or photocleavable) protecting groups (PPGs), also known as caged or photocaged compounds, are used to enable non-invasive spatiotemporal photochemical control over the release of species of interest. Recent years have seen the development of PPGs activatable by biologically and chemically benign visible and near-infrared (NIR) light. These long-wavelength-absorbing moieties expand the applicability of this powerful method and its accessibility to non-specialist users. This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide). The text also covers visible- and NIR-light-induced photosensitized release using molecular sensitizers, quantum dots, and upconversion and second-harmonic nanoparticles, as well as release via photodynamic (photooxygenation by singlet oxygen) and photothermal effects. Release from photoactivatable polymers, micelles, vesicles, and photoswitches, along with the related emerging field of photopharmacology, is discussed at the end of the review.
219 citations
TL;DR: In this article, the adsorption properties of a variety of atoms (H, O, N, S, and C), molecules (N2, HCN, CO, NO, and NH3) and molecular fragments (CN, NH2, NH, CH3, CH2, CH, HNO, NOH, and OH) are calculated on the (0001) facet of ruthenium using periodic, selfconsistent, density functional theory calculations (DFT-GGA) at 1/4 ML coverage.
169 citations
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TL;DR: The vascular effects of EDRF released from perfused bovine intrapulmonary artery and vein were compared with the effects of NO delivered by superfusion over endothelium-denuded arterial and venous strips arranged in a cascade to determine whether nitric oxide (NO) is responsible for the vascular smooth muscle relaxation elicited by endothelia-derived relaxing factor (EDRF).
Abstract: The objective of this study was to determine whether nitric oxide (NO) is responsible for the vascular smooth muscle relaxation elicited by endothelium-derived relaxing factor (EDRF). EDRF is an unstable humoral substance released from artery and vein that mediates the action of endothelium-dependent vasodilators. NO is an unstable endothelium-independent vasodilator that is released from vasodilator drugs such as nitroprusside and glyceryl trinitrate. We have repeatedly observed that the actions of NO on vascular smooth muscle closely resemble those of EDRF. In the present study the vascular effects of EDRF released from perfused bovine intrapulmonary artery and vein were compared with the effects of NO delivered by superfusion over endothelium-denuded arterial and venous strips arranged in a cascade. EDRF was indistinguishable from NO in that both were labile (t1/2 = 3-5 sec), inactivated by pyrogallol or superoxide anion, stabilized by superoxide dismutase, and inhibited by oxyhemoglobin or potassium. Both EDRF and NO produced comparable increases in cyclic GMP accumulation in artery and vein, and this cyclic GMP accumulation was inhibited by pyrogallol, oxyhemoglobin, potassium, and methylene blue. EDRF was identified chemically as NO, or a labile nitroso species, by two procedures. First, like NO, EDRF released from freshly isolated aortic endothelial cells reacted with hemoglobin to yield nitrosylhemoglobin. Second, EDRF and NO each similarly promoted the diazotization of sulfanilic acid and yielded the same reaction product after coupling with N-(1-naphthyl)-ethylenediamine. Thus, EDRF released from artery and vein possesses identical biological and chemical properties as NO.
4,997 citations
01 Jan 1988
TL;DR: L-Arginine is required for the activation of macrophages to the bactericidal/tumoricidal state and suggests that nitric oxide is serving as an intracellular signal for this activation process in a manner similar to that very recently observed in endothelial cells, where nitrics oxide leads to vascular smooth muscle relaxation.
Abstract: Previous studies have shown that murine macrophages immunostimulated with interferon gamma and Escherichia coli lipopolysaccharide synthesize NO2-, NO3-, and citrulline from L-arginine by oxidation of one of the two chemically equivalent guanido nitrogens. The enzymatic activity for this very unusual reaction was found in the 100,000g supernatant isolated from activated RAW 264.7 cells and was totally absent in unstimulated cells. This activity requires NADPH and L-arginine and is enhanced by Mg2+. When the subcellular fraction containing the enzyme activity was incubated with L-arginine, NADPH, and Mg2+, the formation of nitric oxide was observed. Nitric oxide formation was dependent on the presence of L-arginine and NADPH and was inhibited by the NO2-/NO3- synthesis inhibitor NG-monomethyl-L-arginine. Furthermore, when incubated with L-[guanido-15N2]arginine, the nitric oxide was 15N-labeled. The results show that nitric oxide is an intermediate in the L-arginine to NO2-, NO3-, and citrulline pathway. L-Arginine is required for the activation of macrophages to the bactericidal/tumoricidal state and suggests that nitric oxide is serving as an intracellular signal for this activation process in a manner similar to that very recently observed in endothelial cells, where nitric oxide leads to vascular smooth muscle relaxation [Palmer, R. M. J., Ashton, D. S., & Moncada, S. (1988) Nature (London) 333, 664-666].
1,496 citations
TL;DR: Palmer et al. as mentioned in this paper showed that macrophages immunostimulated with interferon gamma and Escherichia coli lipopolysaccharide synthesize NO2-, NO3-, and citrulline from L-arginine by oxidation of one of the two chemically equivalent guanido nitrogens.
Abstract: Previous studies have shown that murine macrophages immunostimulated with interferon gamma and Escherichia coli lipopolysaccharide synthesize NO2-, NO3-, and citrulline from L-arginine by oxidation of one of the two chemically equivalent guanido nitrogens. The enzymatic activity for this very unusual reaction was found in the 100,000g supernatant isolated from activated RAW 264.7 cells and was totally absent in unstimulated cells. This activity requires NADPH and L-arginine and is enhanced by Mg2+. When the subcellular fraction containing the enzyme activity was incubated with L-arginine, NADPH, and Mg2+, the formation of nitric oxide was observed. Nitric oxide formation was dependent on the presence of L-arginine and NADPH and was inhibited by the NO2-/NO3- synthesis inhibitor NG-monomethyl-L-arginine. Furthermore, when incubated with L-[guanido-15N2]arginine, the nitric oxide was 15N-labeled. The results show that nitric oxide is an intermediate in the L-arginine to NO2-, NO3-, and citrulline pathway. L-Arginine is required for the activation of macrophages to the bactericidal/tumoricidal state and suggests that nitric oxide is serving as an intracellular signal for this activation process in a manner similar to that very recently observed in endothelial cells, where nitric oxide leads to vascular smooth muscle relaxation [Palmer, R. M. J., Ashton, D. S., & Moncada, S. (1988) Nature (London) 333, 664-666].
1,494 citations
Journal Article•
868 citations
TL;DR: In this article, a ligand electrochemical parameter, El (L), is described to generate a series which may be used to predict M(n)/M(n-1) redox potentials by assuming that all ligand contributions are additive.
Abstract: : A ligand electrochemical parameter, El (L), is described to generate a series which may be used to predict M(n)/M(n-1( redox potentials by assuming that all ligand contributions are additive. In this fashion it performs a similar purpose to the Dq parameter in electronic spectroscopy. The parameter is defined as 1/6 that of the Ru(III)/Ru(II) potential for species RuL6 in acetontrile. The El(L) values for over 200 ligands are presented and the model is tested over a wide range of coordination complexes and organometallic species. The redox potential of a M(n)/M(n-1) couple is defined to be equal to:- E(calc) = f Sigma EL (L) + c. The values of f and C, which are tabulated, depend upon the metal and redox couple, and upon spin state and stereochemistry, but, in organic solvents, are generally insensitive to the net charge of the species. Consideration is given to synergism, the potentials of isomeric species, and the situations where the ligand additivity model is expected to fail. In this initial study, the redox couples are restricted almost exclusively to those involving the loss or addition of an electron to the tzg (in Oh) sub-level.
832 citations