Metal-ligand multiple bonds. Oxo, imido and nitrido complexes of ruthenium and osmium

Ru=O complexes have been demonstrated to be competent oxidants for oxidation of saturated hydrocarbons and epoxidation of alkenes . Photoexcitation of transdioxoosmium( V1) gives rise to super-oxidizing complexes having EO >2.2 V vs. n.h.e.. Some cationic RuZN and OsZN complexes are good model system for study of the mechanism of metalcatalysed oxidation of ammonia to nitrite and activation of diiiitrogen molecule. With 2,3-diamino-2,3-dimethylbutane as ligand, reversible Os(1V)-amide/Os(III)-amine and Ru(V)- imido/Ru(II)-amine redox couplexes are observed.published_or_final_versio

Ruthenium nanoparticles supported on hydroxyapatite as an efficient and recyclable catalyst for cis-dihydroxylation and oxidative cleavage of alkenes

Impregnation of hydroxyapatite with colloidal ruthenium results in the formation of a catalyst that effects cis-dihydroxylation and oxidative cleavage of alkenes to their respective cis-1,2-diols and carbonyl products in good to excellent yields (see scheme). The supported ruthenium catalyst can be easily recycled and reused for consecutive reaction runs without significant deterioration of the catalytic activities. R1, R2 = H, alkyl, aryl.postprin

Ruthenium-oxo and -tosylimido porphyrin complexes for epoxidation and aziridination of alkenes

Dioxoruthenium(VI) porphyrins including those containing chiral porphyrinato ligands can be readily prepared by oxidation of [Ru 11(Por)(CO)(MeOH)] with PhIO or metachloroperoxybenzoic acid. Similar reactions with PhINTs gave [Ru VI(Por)(NTs) 2] isolated as air stable solids at room temperature. The [Ru VI(Por)O 2] complexes are competent oxidants for epoxidation of alkenes with high selectivities. Enantioselective epoxidation of alkenes giving the corresponding organic epoxides with moderate to good enantioselectivites have also been achieved using chiral [Ru VI(D 4-Por)O 2] [D 4-H 2Por= 5,10,15,20-tetrakis-(IS,4R,5R,8S-1,2,3,4,5,6,7,8-octahydro-1,4:5,8- dimethanoanthracen-9-yl)porphyrin] and [Ru VI(D 2-Por)O 2] complexes. The mechanism of alkene epoxidation by [Ru VI(Por)O 2] has been examined. Procedures for catalytic epoxidation of alkenes using ruthenium porphyrin catalysts has also been developed. [Ru VI(Por)(NTs) 2] was found to undergo aziridination of alkenes and amidation of alkanes in organic solvents at room temperature. ©1999 IUPAC.published_or_final_versio

Sodium trans-Dicyano[N,N'-1,2-phenylenebis(2-pyridinecarboxamido)]cobaltate(III)

The Co atom in the [ColII(CN)2(CI8HI2N402)] - complex anion is hexacoordinate with a distorted octahedral geometry. The four N atoms in the amide ligand occupy equatorial positions and are coplanar to within 0.007A. The two CN groups are coordinated to Co in a trans configuration. The Na cation interacts with four complex anions through their cyanide-N and amide-O atoms, thereby adopting a distorted tetrahedral coordination.published_or_final_versio

Self-assembled functional molecular materials for optoelectronic applications

There has been a growing interest to develop functional organic and organometallic materials in nano-scale by self assembly reactions as these materials could have unique electronic properties and applications. We have found that functionalized organometallic nano-wires which the formations are directed by weak Pt⋯Pt interactions along the dimension of the aggregates can be readily obtained by self-assembly reactions. These platinum(II) nano-wires exhibit interesting photophysical properties, vapochromic behavior, and could be used in the fabrication of organic (light-emitting) field-effect transistors.1,2 We have also found that thermally stable coordination polymers (with decomposition temperature up to 490°C), employing Zn 2+ as template metal ion and Schiff base or terpyridine as repeating chelating units, could be easily synthesized by self-assembly reactions. 3,4 These zinc (II) coordination polymers exhibit intense blue to green photoluminescence, and their thin-film samples have PL quantum yields up to 0.55. Polymer light-emitting devices (PLEDs) employing these coordination polymers as emitters give blue and green EL with turn-on voltage as low as 5 V and maximum efficiency up to 2.0 cd A-1. © 2009 Materials Research Society.published_or_final_versionThe 2008 Fall Meeting of the Materials Research Society, Boston, MA., 1-5 December, 2008. In Materials Research Society Symposium Proceedings, 2008, v. 1149, p. 1-1

Phosphorescent Plalladium Complexes with Long-Lived Excited State

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Proteomic characterization of the cytotoxic mechanism of gold (III) porphyrin 1a, a potential anticancer drug

There has been increasing interest in the potential applications of gold (III) complexes as anticancer drugs with higher cytotoxicity and fewer side effects than existing metal anticancer drugs. Our previous findings demonstrated that gold (III) porphyrin la preferentially induced apoptosis in a cancer cell line (SUNE1). In this study, we identified differentially expressed proteins related to the drug's cytotoxic action by comparing the protein alterations induced by gold (III) porphyrin la and cisplatin treatments. Several clusters of altered proteins were identified, including cellular structure and stress-related chaperone proteins, proteins involved in reactive oxygen species and enzyme proteins, translation factors, proteins that mediate cell proliferation or differentiation, and proteins participating in the internal degradation systems. Our results indicated that multiple factors leading to apoptosis were involved in drug cytotoxicity in SUNE1 cells. The balance between pro-apoptotic and anti-apoptotic signals determined the final fate of cancer cells. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.postprin

Effects of fluorine plasma and ammonia annealing on pentacene thin -film transistor with ZrLaOx as gate dielectric

Pentacene organic thin-film transistor (OTFT) based on ZrLaOx gate dielectric is proposed and has been fabricated. The effects of fluorine plasma and ammonia annealing on the properties of the OTFT have been studied. It reveals that the plasma treatment can greatly improve carrier mobility and shift the threshold voltage in the positive direction. With a threshold voltage less than 0.5 V, the OTFT can work at very low supply voltage. On the other hand, the ensuing ammonia annealing counteracts the plasma treatment and shifts the threshold voltage in the opposite direction. © 2012 IEEE.published_or_final_versio

Theoretical studies on the photophysical properties of luminescent pincer gold(III) arylacetylide complexes: the role of π-conjugation at the C-deprotonated [C^N^C] ligand

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Effect of laser intensity on the determination of intermolecular electron transfer rate constants - Observation of Marcus inverted region in photoinduced back electron transfer reactions

The light intensity and concentration dependence of the photoproduct yield are investigated in a monophotonic process. The relationship of the photoproduct yield with the laser intensity and the complex concentration for a monophotonic process is derived under laser flash photolysis. The relationship is confirmed experimentally in a monophotonic process, i.e., triplet-triplet transition for a Cu(I) complex Cu6(DMNSN′)6 (DMNSN′=4,6-dimethylpyrimidine-2-thiolate). At low light intensity, the relationship can be approximated by a linear inverse square root dependence on the light intensity. Based on this equation, a method is proposed to determine the intrinsic back electron transfer rate constant kET b in photoinduced intermolecular electron transfer reactions, precluding the effect from the diffusional encounter pairs. The Marcus "inverted region" is observed by using the method in photoinduced back electron transfer reactions of [Au2(dppm)2](ClO4)2 (dppm=bis(diphenylphosphino)methane) with a series of substituted pyridinium acceptors. © 1998 American Institute of Physics.published_or_final_versio