116261-58-6Relevant academic research and scientific papers
Studies and Photoreactions of Os3(CO)12 with Chlorocarbons and with Triphenylphosphine in Solution
Tyler, David R.,Altobelli, Mark,Gray, Harry B.
, p. 3022 - 3024 (1980)
Irradiation (254, 313, 366, 405 nm) of Os3(CO)12 in CCl4, CHCl3, or CH2Cl2 solution at room temperature produces Os(CO)4Cl2 in low quantum yield (0.002 in CCl4 at 313 nm).A reasonable pathway for the photoreaction involves Os3(CO)12Cl2 as an intermediate, as irradiation of the complex at 313 nm in CCl4 gives Os(CO)4Cl2 with a quantum yield of 0.31.Irradiation of Os3(CO)12 under 6 atm CO in acetonitrile solution at room temperature gives no reaction; however, in the absence of carbon monoxide, Os3(CO)12 and PPh3 photoreact to give Os3(CO)11PPh3, and Os3(CO)10(PPh3)2 and Os3(CO)9(PPh3)3 are secondary and tertiary products.Prolonged irradiation of the trisubstituted complex in the presence of PPh3 yields Os(CO)3(PPh3)2 (Φ = 0.005 at 366 nm).The fact that fragmentation of the cluster is a principal photochemical pathway for Ru3(CO)12 but not for Os3(CO)12 is probably due to differences in M-M bond strengths (Os-Os > Ru-Ru) and also to the different character of the lowest energy electronic excited states of the two complexes (? -> ?*, Ru3(CO)12; ?*' -> ?*, Os3(CO)12).
Wavelegth-Dependent Primary Photoprocesses of Os3(CO)12 in Fluid Solution and in Rigid Alkane Glasses at Low Temperature: Spectroscopic Detection, Characterization, and Reactivity of Coordinatively Unsaturated Os3(CO)11
Bentsen, James G.,Wrighton, Mark S.
, p. 4518 - 4530 (1987)
Wavelegth-dependent photochemistry is reported for Os3(CO)12 in hydrocarbon solutions at 298 and 195 K and in rigid hydrocarbon glasses at 90 K.Near-UV and vis irradiation of 0.2 mM Os3(CO)12 at 298 k in alkane solutions containing 5 mM L yields mainly Os3(CO)11L (L = PPh3, P(OMe)3) as the initial photoproduct with a wavelegth-dependent quantum yield Φ436nm 366nm =0.017 +/- 0.001, and Φ313nm = 0.050 +/- 0.003 for L = PPh3, independent of the presence of added o.1 M tetrahydrofuran.Photosubstitution of PPh3 for CO is not affected by added 1 M CCl4, and the 366 nm quantum yield does not change on increasing the PPh3 concentration to 0.1 M, consistent with photodissociative loss of CO from an upper level excited state.Electronic spectral features for Os3(CO)12 become well-resolved in an alkane glass of 90 K; low-energy excitation into the first (382 nm: 10a1' -> 16e'; 1A1' -> 1E') or second (320 nm: 15e' -> 6a2'; 1A1' -> 1E') absorbtions for Os(CO)12 yields no net photochemistry in the 90 K alkane glass.However, excitation into the third electronic absorbtion (278 sh nm: 14e' -> 6a2'; 1A1' -> 1E') of 0.1 mM Os3(CO)12 yields loss of one CO as the only FTIR detected photoreaction to yield a single product, formulated as axially vacant Os3(CO)11 on the basis of FTIR and UV-vis spectral characterization and reaction chemistry.While the photogenerated Os(CO)11 reacts with 13CO at low temperature to give an axial-13CO-Os3(CO)11(13CO), UV irradiation of axial-13CO-Os3(CO)11(13CO) in a 90 K methylcyclohexane glass yields dissociative CO loss in a ratio of 12CO/13CO of greater than 28.These results suggest photodissociative loss of equatorial CO from Os3(CO)12, followed by rearrangement of equatorially vacant Os3(CO)11 to the axially vacant form.Photogenerated Os3(CO)11 reacts with two electron donor ligands to yield Os3(CO)11L complexes (L = N2,C2H4, PPh3, 1-pentene, 2-MeTHF) and with H2 to yield H2Os3(CO)11.The H2Os3(CO)11 complex has been detected by FTIR as an intermediate in the direct photoconversion (Φ366nm = 0.02) of Os3(CO)12 to H2Os3(CO)10 in H2-saturated alkane solutions at 298 K.Near-UV irradiation of H2Os3(CO)11 cleanly yields H2Os3(CO)10 and free CO at 298 or 90 K.Selective excitation into the second absorbtion of Os3(CO)12 at 90 K yields inefficient associative photosubstitution of strong ?-acceptors (C2H4, C5H10, 13CO) but not N2 or 2-MeTHF for CO.In fluid solutions, competitive photofragmentation is correlated with long wavelegth irradiation and with strong ?-acceptor ligands (CO, C2H4, not PPh3).
KINETICS OF REACTIONS OF HYDROGEN WITH and
Hudson, Robert H. E.,Poe, Anthony J.,Sampson, Clifford N.,Siegel, Andre
, p. 2235 - 2240 (1989)
The kinetics of reactions of with H2 and CO, and of with H2, have been studied in the presence of free MeCN.The reactions involve slow dissocaation of MeCN from the clusters and subsequent competition between MeCN and H2 or CO for the vacant co-ordination site on the intermediate cluster.Rate constans for nucleophilic attack on are in the order MeCN >PPh3 ca.CO > H2 and temperature-dependence studies provide activation enthalpy and entropy differences.These, together with value of 1.34 +/- 0.03 for the deuterium kinetic isotope effect, are consistent with a simple three-centre transition state for reaction of with H2.The cluster reacts with MeCN to form and equilibrium data for this reaction have been obtained.
Control of the photochemistry of Ru3(CO)12 and Os3(CO)12 by variation of the solvent1
Leadbeater, Nicholas E.
, p. 211 - 216 (1999)
The synthetic potential of the photosubstitution of CO by two-electron donor ligands in M3(CO)12 [M=Ru, Os] has been investigated. When used as photolysis media, diethyl ether, ethyl acetate and acetonitrile act as photofragmentation quenchers allowing for the synthesis of photosubstitution products in high yield. UV photolysis of M3(CO)12 with added triphenylphosphine in these photolysis media leads to M3(CO)12-n(PPh3)n (n=1, 2 or 3). Prolonged photolysis with added tricyclohexylphosphine generates the highly sterically crowded complex M3(CO)9(PCy3)3. Photolysis with thiols, RSH (R=Et, Ph), leads to the thiolato complexes HM3(μ-SR)(CO)10, prolonged photolysis of which generates the corresponding sulphido cluster M3(μ3-S)(CO)10. Photolysis of M3(CO)12 in acetonitrile with no added ligand results in the generation of M3(CO)12-n(MeCN)n (n=1 or 2). This offers a route to these complexes without the need for the use of oxidising agents such as trimethylamine-N-oxide. Photolysis of an ethene-saturated diethyl ether or ethyl acetate solution of M3(CO)12 leads to no net photoreaction in the case of ruthenium, whereas, for osmium, the olefin complex Os(CO)4(η2-C2H4) is formed. This highlights the difference in the photosubstitution mechanism for Ru3(CO)12 and Os3(CO)12.
The reaction of triphenylphosphine selenide with triosmium clusters: a facile cluster coupling through a selenium atom
Leong, Weng Kee,Leong, Wei Lin Janet,Zhang, Junlian
, p. 1087 - 1090 (2001)
The room temperature reactions of Ph3PSe with the triosmium clusters Os3(CO)11(CH3CN), Os3(CO)10(CH3CN)2 and Os3(μ-H)2(CO)10 have been investigated. The reaction with an equimolar amount of Os3(CO)11(CH3CN) afforded the known clusters Os3(μ3-Se)2(CO)9, 1, and Os3(CO)11(PPh3), 2, and the new cluster Os3(μ3-Se)(CO)9(PPh3), 3. The analogous reaction with Os3(CO)10(CH3CN)2 gave 1 and 2; reaction with 0.5 equivalent of the cluster gave 1 quantitatively. The reaction with Os3(μ-H)2(CO)10 gave two new clusters, viz. Os3(μ3-Se)(μ-H)2(CO)8(PPh3), 4a, and Os6(μ3-Se)(H)(μ-H)3(CO)18(PPh3)2, 5a. Single crystal structures of 3, 4a and 5a have been obtained. Cluster 3 possesses bridging carbonyls; these appear to have been lost on elongation of the osmium-osmium bonds by bridging hydrides in 4a. The structure of 5a is novel and comprises a naked μ3-Se atom bridging two triosmium moieties; an Os3(μ-H0(CO)10 unit and an Os3(H)(μ-H)2(CO)8(PPh3)2 unit.
THE SYNTHESIS AND CHARACTERISATION OF NEW TRIOSMIUM AND TRIRUTHENIUM MAIN-GROUP METAL CLUSTERS M3(H)(CO)11(M'R3) AND Os3(H)(CO)10(CH3CN)(M'R3) (M=Os, Ru; M'=Ge, Sn; R, aryl, alkyl)
Burgess, K.,Guerin, C.,Johnson, B. F. G.,Lewis, J.
, p. C3 - C6 (1985)
Displacement of the (CH3CN) ligand from the compounds M3(CO)12-n-(MeCN)n (n=1 or 2) by organo-germanes and -stannanes provides a general method for the preparation of triosmium- and triruthenium-Main-Group metal clusters of the type M3(H)(CO)11(M'R3) and Os3(H)(CO)10(CH3CN)(M'R3) (M=Ru, Os; M'= Ge, Sn).
The Preparation, Characterisation, and Some Reaction of
Johnson, Brian F. G.,Lewis, Jack,Pippard, David A.
, p. 407 - 412 (1981)
The cluster has been prepared from the reaction of with NMe3O in the presence of MeCN.This cluster reacts with ligands L(L = CO, PPh3, CH3C6H4SO2CH2NC-p, C2H4 or C5H5N) to produce derivatives and with HX (X = Cl,
Efficient microwave syntheses of the compounds Os3(CO)11L, L = NCMe, py, PPh3
Jung, Jade Y.,Newton, Brittney S.,Tonkin, Michelle L.,Powell, Cynthia B.,Powell, Gregory L.
, p. 3526 - 3528 (2009)
The results of simple microwave-assisted ligand substitution reactions of Os3(CO)12 are reported. In a remarkably short period of time, the labile complex Os3(CO)11(NCMe) is prepared in high yield without the ne
Cytotoxic triosmium carbonyl clusters: A structure-activity relationship study
Lee, Hui Zhi Shirley,Leong, Weng Kee,Top, Siden,Vessieres, Anne
, p. 1453 - 1457 (2014/07/21)
A structure-activity relationship (SAR) study of the triosmium carbonyl cluster Os3(CO)10(NCCH3)2 was carried out with a series of clusters of the general formula Os 3(CO)12-nLn, cationic osmium clusters and a hemi-labile maltolato-Os cluster. The SAR results showed that good solubility in DMSO and at least one vacant site are required for cytotoxicity. In vitro evaluation of these new compounds showed that some are selectively active against estrogen receptor (ER)-independent MDA-MB-231 breast cancer cell lines relative to ER-dependent MCF-7 breast cancer cells, suggesting that the compounds have a different biological target specific to MDA-MB-231 cells. In particular, the maltolato cluster exhibits strong antiproliferative activity, with an IC50 value of 3 μM after only 24 h incubation. Additionally, biochemical assays conducted with the cationic cluster show that it induces apoptosis, although a biological target has not yet been identified. Further research to establish the molecular targets of these compounds and to develop improved organometallic clusters as potential breast cancer therapeutics is underway. The land of Os(mium): A structure-activity relationship study of a series of triosmium carbonyl clusters revealed that good solubility and a vacant site are necessary for activity. The newly synthesized compounds were more selective toward estrogen receptor (ER)-negative breast cancer cells versus ER-positive cells, indicating a different biological target than for tamoxifen.
Heterosite effects in novel heteronuclear clusters [Os 2Ru(CO)11(PPh3)] and [Os2Ru(CO) 10(2-acetylpyridine-N-isopropylimine)]
Vergeer, Frank W.,Lutz, Martin,Spek, Anthony L.,Calhorda, Maria J.,Stufkens, Derk J.,Hartl, Frantisek
, p. 2206 - 2222 (2007/10/03)
A new synthetic route towards the mixed-metal cluster [Os 2Ru(CO)12] is described together with the syntheses of its PPh3 and iPr-AcPy (iPr-AcPy = 2-acetylpyridine-N-isopropylimine) derivatives. The molecular structures of the novel clusters [Os 2Ru(CO)11(PPh3)] and [Os2Ru(CO) 10(iPr-AcPy)] were determined on the basis of crystalline solid solutions of the Os2Ru and corresponding Os3 species. The structures reveal that coordination of the Lewis bases occurs exclusively at the ruthenium site of [Os2Ru(CO)12], which is in agreement with density functional theory (DFT) calculations on several structural isomers of these compounds. According to the time-dependent DFT results, the lowest optically accessible excited state of [Os 2Ru(CO)10(iPr-AcPy)] has a prevailing σ(Ru-Os2)-π*(iPr-AcPy) character, with a partial σσ* (Ru-Os2) contribution. In weakly coordinating 2-chlorobutane, the excited state has a lifetime τ = 10.4 ± 1.2 ps and produces biradicals considerably faster than observed for [Os 3(CO)10(iPr-AcPy) (τ = 25.3 ± 0.7 ps). In coordinating acetonitrile, the excited state of [Os2Ru(CO) 10(iPr-AcPy)] decays mono-exponentially with a lifetime τ = 2.1 ± 0.2 ps. In contrast to [Os3(CO)10(iPr-AcPy)] that forms biradicals as the main primary photoproduct even in strongly coordinating solvents, zwitterion formation from the solvated lowest excited state is observed for the heterometallic cluster. This is concluded from time-resolved absorption studies in the microsecond time domain. Due to the lower tendency of the coordinatively unsaturated +Ru(CO) 2-(iPr-AcPy-/0) moiety to bind a Lewis base, the heteronuclear biradical and zwitterionic photoproducts live significantly shorter than their triosmium counterparts. The influence of the weaker Os2-Ru(iPr-AcPy) bond on the redox reactivity is clearly reflected in very reactive radical anions formed upon electrochemical reduction of [Os 2Ru(CO)10(iPr-AcPy)]. The dimer [-Os(CO) 4-Os(CO)4-Ru(CO)2(iPr-AcPy)]2 2- is the only IR-detectable intermediate reduction product. The dinuclear complex [Os2(CO)8]2- and insoluble [Ru(CO)2(iPr-AcPy)]n are the ultimate reduction products, proving fragmentation of the Os2Ru core. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
