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  • Ruthenium  (23)
  • Wiley-Blackwell  (23)
  • 2015-2019
  • 1995-1999  (23)
  • 1999  (23)
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  • 2015-2019
  • 1995-1999  (23)
Year
  • 1
    ISSN: 1434-1948
    Keywords: Ruthenium ; Coordination chemistry ; Paramagnetic complexes ; Magnetic properties ; Ion exchange ; Antitumor agents ; Colon tumors ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Indazolium trans-tetrachlorobis(indazole)ruthenate(III) exhibits excellent results against different tumor models in vitro and in vivo. To improve the water solubility necessary for the introduction of this tumor-inhibiting compound into clinical trials, we synthesized the corresponding sodium salt in a two-step ion exchange via the tetramethylammonium salt. The sodium salt shows a 35-fold higher solubility in water relative to the indazolium salt. We also synthesized the n-butylammonium, n-octylammonium, and tetraphenylphosphonium salts, all of which showed improved solubility in organic solvents. The X-ray crystal structure of the latter could be solved, proving the trans configuration of the complex anion. In spite of the paramagnetic RuIII center an assignement of the coordinated indazole protons could be made with the help of a COSY experiment.
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  • 2
    ISSN: 1434-1948
    Keywords: Ruthenium ; Triazole ; Titanium ; Electron Transfer ; Sensitizers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes [Ru(dcb)2(L)] {L = 3-(2-hydroxyphenyl)-5-(pyridin-2-yl)-1,2,4-triazole (2-ppt), 3-(4-hydroxyphenyl)-5-(pyridin-2-yl)-1,2,4-triazole (4-ppt), 3,5-bis(pyrazin-2-yl)-1,2,4-triazole (bpzt), 3-(2-hydroxyphenyl)-5-(pyrazin-2-yl)-1,2,4-triazole (2-ppzt) and dcb = 4,4′-(CO2H)2-2,2′-bipyridine} have been synthesized, spectroscopically characterized and anchored to nanocrystalline TiO2 electrodes for the conversion of light into electricity in regenerative solar cells. The different efficiencies observed have been rationalized on the basis of an analytical expression relating the incident photon-to-current conversion efficiency (IPCE) to the kinetic parameters of the relevant electron transfer processes involved in the solar cell.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1523-1529 
    ISSN: 1434-1948
    Keywords: Boron ; Iron ; Ruthenium ; Boryl Complexes ; Borylene Complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactivity of aminodihaloboranes R2NBX2 (R = Me, SiMe3; × = Cl, Br) towards transition metal complexes of the type Na[(η5-C5R′5)M(CO)2)] (M = Fe, Ru; R′ = H, Me) was investigated. In the case of Me2NBBr2 and M = Fe the borylcomplexes [(η5-C5R′5)(CO)2Fe{BBr(NMe2)}] (C5R′5 = C5H59a; C5R′5 = C5H4Me 9b; C5R′5 = C5Me510) were obtained. The compounds 9aand 9bwere formed together with the corresponding bridged borylene complexes [μ-BNMe2(μ-CO){(η5-C5R′5)Fe(CO)}2] (C5R′5 = C5H511a; C5R′5 = C5H4Me 11b) in a 1:1 ratio, the latter, however, could be isolated from these mixtures as pure materials. In addition the novel boryl and borylene ruthenium complexes [(η5-C5H5)(CO)2Ru{BX(NMe2)}] (X = Cl 12a; × = Br 12b), [(η5-C5H5)(CO)2Ru{BCl{NSiMe3{BClN(SiMe3)2}}}] (13) and [μ-BN(SiMe3)2(μ-CO){(η5-C5H5)Ru(CO)}2] (14) were obtained by similar methods. All compounds were characterized by multinuclear NMR and IR spectroscopy. The structure of 13 in the solid state was determined by a single-crystal X-ray diffraction study.
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  • 4
    ISSN: 1434-1948
    Keywords: Asymmetric catalysis ; Transfer hydrogenation ; Ruthenium ; Amino alcohol ligands ; X-ray structure ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of ruthenium-amino alcohol precursors in the catalytic cycle of asymmetric hydrogen transfer reactions was studied using two C2-symmetrical tetradentate ligands (1 and 2) that were synthesised from (nor)ephedrine. The structure of the catalyst precursor was examined through catalysis and NMR experiments. It was shown that the active catalyst contains one ligand per metal, which coordinates in a didentate N,O fashion (9). In addition, a RuIICl2 complex, in which N,N′-bis(2-hydroxy-1-methyl-2-phenylethyl)-1,2-diaminoethane (1) coordinates through two nitrogen atoms, was structurally characterised by X-ray diffraction (8). - Based on the results of this study a series of new amino alcohol ligands was synthesised from easily available starting materials. Optimisation of the amino alcohol ligand structure resulted in the most effective chiral amino alcohol ligand (5) so far that is capable of reducing acetophenone at 0 °C with up to 97% ee in the RuII-catalysed transfer hydrogenation.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1-5 
    ISSN: 1434-1948
    Keywords: Terpyridine ligands ; Ferrocenes ; Iron ; Ruthenium ; Cyclic voltammetry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,2′:6′,2′′-Terpyridines bearing a substituent × in the 4′-position [3a: × = Fc-C≡C-p-C6H4; 3b: × = Fc#-C≡C-p-C6H4; Fc = (C5H5)Fe(C5H4), Fc# = (C5Me4H)Fe(C5Me4)] were prepared by Pd0-catalysed cross-coupling reactions. 3b was characterised by X-ray structure analysis. [(3a)RuCl2(DMSO)] (4a) and [(3b)RuCl2(DMSO)] (4b) were obtained by reaction of [RuCl2(DMSO)4] with 1 equivalent of 3a and 3b, respectively, while the analogous reaction with 2 equivalents afforded [(3a)2Ru][PF6]2 (5a) and [(3b)2Ru][PF6]2 (5b), respectively, after precipitation with aqueous [NH4][PF6]. Similarly, [(3a)Ru(tpy)][PF6]2 (6) was isolated from the reaction of 4a with 2,2′:6′,2′′-terpyridine (tpy). Compounds 3 and 5 were investigated by cyclic voltammetry, which revealed that the introduction of eight methyl groups leads to the expected cathodic shift of the E0′ values of ca. 0.44 V for the ferrocenyl-centered redox processes.
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  • 6
    ISSN: 1434-1948
    Keywords: Ruthenium ; Halogens ; Carbonyl complexes ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aqueous hydrogen halides HX (X = Cl, Br, I) are shown to be excellent halogen sources for the synthesis of a series of halogen-containing ruthenium mono(2,2′-bipyridine) carbonyl complexes Ru(dmbpy)(CO)2X2 (dmbpy = 4,4′-dimethyl-2,2′-bipyridine), as well as effective reagents for the attack of the Ru-Ru bond in the dimer [Ru(dmbpy)(CO)2Cl]2. Selective syntheses were established for both cis- and trans-halogen complexes in the case of Cl- and of Br-containing derivatives, but the only stable isomer containing iodine was trans(I)-Ru(dmbpy)(CO)2I2. The failure to obtain the cis isomer was probably due to sterical effects. Furthermore, a novel S-bound trans(SCN) analogue was synthesized and structurally characterized. In all experiments, the reaction conditions selected led to complete halogen exchange; no mixed halogen or pseudohalogen complexes were detected.
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  • 7
    ISSN: 1434-1948
    Keywords: Ruthenium ; Nitrogen heterocycles ; Hydrogen bonds ; Antitumor agents ; Crystal structures ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The X-ray structure of the potential antitumour complex trans-[RuCl3(H2O)(admtp)2] · H2O (admtp = 2-amino-5,7-dimethyl[1,2,4]triazolo[1,5-a]pyrimidine) shows unique and very interesting intramolecular hydrogen-bonding properties with the non-bridgehead pyrimidinic nitrogen atom of admtp acting as hydrogen acceptor and the amino group acting as hydrogen donor.Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2005/1999/98348_s.pdf or from the author.
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  • 8
    ISSN: 1434-1948
    Keywords: Cleavage reactions ; C-S cleavage ; Ligand synthesis ; Osmium ; Ruthenium ; S ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In search of a tetradentate thioether thiolate ligand that is more stable toward reductive C-S bond cleavage than the parent ligand ′S4′-H2 [′S4′-H2 = 1,2-bis(2-mercaptophenylthio)ethane], the novel tris-phenylene ligand ′tpS4′-H2 (3) [′tpS4′-H2 = 1,2-bis(2-mercaptophenylthio)phenylene] was synthesized via the nitro and amine compounds ′tpS2(NO2)2′ (1) and ′tpS2(NH2)2′ (2). The coordination of ′tpS4′2- to ruthenium centers resulted in the formation of six-coordinate [Ru(L)(PR3)(′tpS4′)] complexes (R = Et, L = PEt34; R = Ph, L = PPh35, CO 6, DMSO 7). The X-ray structure analyses of 4 and 6 revealed that the thiolate donors occupy trans positions; consequently the ′tpS4′2- ligand coordinates in the same way as the ′S4′2- ligand. The stability of the ′tpS4′2- ligand toward reductive C-S cleavage reactions was shown by the synthesis of [Os(PEt3)2(′tpS4′)] (8). In contrast to [Os(PEt3)2(′S4′)], 8 is stable for unlimited periods of time. The X-ray structure analysis of [Ru(Cl)2(PPh3)(′tpS2(NH2)2′)] (9) demonstrates that the potentially tetradentate ligand ′tpS2(NH2)2′ coordinates in 9 through three donors leaving one NH2 donor dangling.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 341-348 
    ISSN: 1434-1948
    Keywords: N ligands ; S ligands ; Iron ; Ruthenium ; Pentadentate ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to obtain iron and ruthenium complexes which are analogous to [M(L)(′NHS4′)] and [M(L)(′N2H2S3′)] complexes [′NHS4′2- = 2,2′-bis(2-mercaptophenylthio)diethylamine(2-), ′N2H2S3′2- = 2,2′-bis(2-mercaptophenylamino)diethylsulfide(2-)] but have electron-richer metal centers, the new pentadentate amine thiolate ligand ′N3H3S2′-H2 [ = 2,2′-bis(2-mercaptophenylamino)diethylamine] (4) was synthesized. The dianion ′N3H3S2′2- reacted with FeII salts to give high-spin [Fe(′N3H3S2′)] (5) [μeff (293 K) = 3.94 μB], which yielded diamagnetic [Fe(CO)(′N3H3S2′)] (6) upon reaction with CO. Complex 6 exhibits a low-frequency ν(CO) band (1934 cm-1 in THF) indicating an electron-rich Fe center and a strong Fe-CO bond. In spite of this, 6 readily dissociated in solution to 5 and CO. The reaction of [RuCl2(PPh3)3] with ′N3H3S2′2- yielded [Ru(PPh3)(′N3H3S2′)] (7), which proved inert with respect to PPh3 substitution but could be methylated at the thiolate donors. The resulting [Ru(PPh3)(′N3H3S2′-Me2)]I2 (8) proved as inert towards substitution as 7. Complex 8 could reversibly be deprotonated to give [Ru(PPh3)(′N3H2S2′-Me2)]I (11), in the course of which the [RuPN3S2] cores rearrange from CS to C1 symmetry. Reversible protonation/deprotonation was also found with [Ru(NO)(′N3H2S2′)] (9) which formed from [RuCl3(NO)(PPh3)2] and ′N3H3S2′2- in the presence of one additional equivalent of LiOMe. Protonation of 9 with HBF4 gave [Ru(NO)(′N3H3S2′)]BF4 (10). The NMR spectra and the X-ray structure analysis of 8 proved that the [RuPN3S2] cores of 7 and 8 exhibit a CS-symmetrical meso structure. In all other complexes, however, the [MLN3S2] cores exhibit a C1-symmetrical structure. It results from the fac-mer coordination mode of the ′N3H3S2′2- ligand and favors the planarization of amide donors when NH functions are reversibly deprotonated.
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  • 10
    ISSN: 1434-1948
    Keywords: Ruthenium ; Photochemistry ; Photosubstitution ; Diimine chelates ; Sterically hindered ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mixed ruthenium(II) complexes containing 1,10-phenanthroline (or 2,2′-bipyridine) and a sterically congested bidentate ligand such as 2,9-diphenyl-1,10-phenanthroline, 6,6′-dimethyl- or 6,6′-diphenyl-2,2′-bipyridine, or 1-(2′-pyridyl)-3,5-dimethylpyrazole undergo clean and selective ligand substitution under irradiation with visible light. For instance, Ru(phen)2(dmbp)2+ in CH3CN is quantitatively converted to Ru(phen)2(CH3CN)22+ in a photochemical reaction accompanied by expulsion of the sterically hindering chelate dmbp (phen = 1,10-phenanthroline; dmbp = 6,6′-dimethyl-2,2′-bipyridine). Interestingly, 2,2′-bipyridine was found to be photochemically ejected in one case, probably as a consequence of its greater flexibility.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1707-1713 
    ISSN: 1434-1948
    Keywords: Carbene complexes ; Carbonyl complexes ; Diazoalkanes ; Hydrido complexes ; Ruthenium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The five-coordinate compound [RuHCl(CO)(PiPr2Ph)2] (1), which was prepared from RuCl3· 3 H2O and PiPr2Ph in methanol in the presence of NEt3, reacts with CO and with diazoalkanes RCHN2 (R = Ph, H) to give the six-coordinate complexes [RuHCl(CO)2(PiPr2Ph)2] (4) and [RuHCl(CO)(=CHR)(PiPr2Ph)2] (5, 6), respectively. If the reaction of 1 with CH2N2, which at -78 °C affords 6, is carried out at room temperature, the ionic compound [MePiPr2Ph][RuHCl2(CO)(PiPr2Ph)2] (7) is formed. The corresponding PPN salt was obtained from 1 and [PPN]Cl. The X-ray crystal structure analysis of 7 revealed, that the anionic species [RuHCl2(CO)(PiPr2Ph)2]- contains the chloro ligands in cis and the phosphanes in trans disposition. The Ru=CH2 bond of compound 6 is quite labile and, therefore, the CH2 unit is easily displaced by CO or pyridine. From 1 and pyridine, an isomeric mixture of [RuHCl(CO)(py)(PiPr2Ph)2] (9a, b) is formed. Treatment of 1 with HC≡CR (R = H, Ph) yields the five-coordinate vinylruthenium(II) complexes [Ru(CH=CHR)Cl(CO)(PiPr2Ph)2] (12, 13) by insertion of the alkyne into the Ru-H bond. The preparation of [RuHX(CO)-(PiPr2Ph)2] (X = CF3CO2, I) is also reported.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1919-1930 
    ISSN: 1434-1948
    Keywords: Ruthenium ; Chirality ; Cyclopentadienyl complexes ; Kinetics ; Asymmetric catalysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel, functionalized, chiral Cp-ligands with S- and P-donor atoms were designed. Together with known analogues containing ether side-chains they were complexed to ruthenium for use as chiral Lewis-acid catalysts. In the ether complexes [RuCl(η5-C5H4CH2CH2OR)(PPh3)2] {R = Me, (1S)-isobornyl, (1R)-menthyl, (1R)-fenchyl} the Cp-ligand is only η5-coordinated; all attempts to provoke a bidentate, Cp/O coordination were unsuccessful. The sulfide complex [Ru{η5:η1-C5H4CH2CH2S[(1R)-neomenthyl]}(PPh3)2][OTf] contains a bidentate Cp/S-coordinated ligand, but it is unstable. The stable phosphane complex [RuCl(η5:η1-C5H4CH2CH(Me)PPh2)(PPh3)] exists as a 77:23 mixture of diastereomers containing a strongly bidentate Cp/P ligand. The diastereomers interchange, with Ru-Cl bond cleavage as the rate-determining step.Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2005/1999/99126_s.pdf or from the author.
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1141-1149 
    ISSN: 1434-1948
    Keywords: C-C coupling ; Metallacycles ; Metallacyclobutane ; Ruthenium ; Tripodal ligands ; Vinylidene complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Selective coupling of olefins and terminal acetylenes is shown to be effected in the coordination sphere of RuII by the successive intermediacy of vinylidene and ruthenacyclobutane complexes. Subsequent deprotonation of one of the β-hydrogen atoms of the latter by NaOEt yields η3-butadienyl complexes, while in the presence of Cl- rearrangement takes place to give neutral η2-butadiene complexes by a β-hydrogen elimination/reductive elimination sequence. [Ru(tp)(COD)Cl] and [Ru(tp){η3-(P,C,C)-Ph2PCH=CHC(Ph)=CH2}Cl] were the starting materials which were treated with HC≡CR (R = Ph, C6H9, ferrocenyl, CH2Ph, nBu). The η3-butadienyl complexes are nucleophilic at the enynyl carbon atom reacting readily with the electrophiles H+ and I2 to give the corresponding η2-butadienyl complexes. X-ray structures of representative products are given.
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  • 14
    ISSN: 1434-1948
    Keywords: Ruthenium ; Thiolate ligands ; Dithiolate ligands ; Substitution reactions ; Electrophilic additions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The known dithiolate-bridged ruthenium(I) complex [Ru2(μ-bdt)(CO)6] (1) (bdt = benzene-1,2-dithiolate) has been prepared in fair yield (55%) by the sequential treatment of RuCl3·nH2O with carbon monoxide, benzene-1,2-dithiol and zinc in a one-pot reaction. Complex 1 reacts readily with monodentate phosphanes to give, stepwise, the penta- and tetracarbonyl derivatives [Ru2(μ-bdt)(CO)6-n(PR3)n] (n = 1, 2; R = Ph, Cy, iPr). However, the reaction of 1 with one equivalent of bis(diphenylphosphanyl)methane (dppm) affords a mixture of complex 1 and the disubstituted derivative [Ru2(μ-bdt)(CO)4(η1-dppm)2], in which the dppm ligands are monodentate. This mixture is subsequently transformed into a polymeric material of formula [{Ru2(μ-bdt)(CO)4}(μ-dppm)]n, which consists of binuclear {Ru2(μ-bdt)(CO)4} units linked to each other by bridging dppm ligands. The use of two equivalents of dppm leads to [Ru2(μ-bdt)(CO)4(η1-dppm)2] in quantitative yield. The X-ray diffraction structure of [Ru2(μ-bdt)(CO)4(PiPr3)2] (3c) confirms that the phosphane ligands are located in axial positions, cis to both sulfur atoms, and that the Ru-Ru distance is short [2.6753(7) Å]. A comparative study of the reactivity of complexes 1 and 3c with the electrophiles H+, [Au(PPh3)]+, and HgCl2 has allowed the isolation of the derivatives [Ru2(μ-H)(μ-bdt)(CO)6-n(PiPr3)n][BF4] (n = 0, 2), [Ru2Au(μ-bdt)(CO)6-n(PiPr3)n(PPh3)][BF4] (n = 0, 2) and [Ru2HgCl2(μ-bdt)(CO)6-n(PiPr3)n] (n = 0, 2), respectively.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 2315-2321 
    ISSN: 1434-193X
    Keywords: Asymmetric catalysis ; Transfer hydrogenations ; Ruthenium ; Coordination chemistry ; Nitrogen heterocycles ; Synthetic methods ; Hydrogenations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chiral 1,2,3,4-tetrahydroisoquinoline intermediates in the Rice and Beyerman routes to morphine, (+)-(R)-1-(3-hydroxy-4-methoxybenzyl)-6-methoxy-1,2,3,4-tetrahydroisoquinoline (6) and (+)-(R)-1-(3,5-dibenzyloxy-4-methoxybenzyl)-6-methoxy-1,2,3,4-tetrahydroisoquinoline (5), were prepared in high ee by ruthenium-catalyzed asymmetric transfer hydrogenation of the corresponding imine precursors (Noyori method). The yield of the key raw material in the Beyerman route, 3,5-dibenzyloxy-4-methoxyphenylacetic acid (1), starting from gallic acid methyl ester (7) was improved by a factor of 5 over previously described syntheses. Key steps in the new procedure are the selective formation of methyl 3,5-dihydroxy-4-methoxybenzoate (9) via the 3,5-diacetate and an improved benzylation of the hydroxyl groups in 9.
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  • 16
    ISSN: 1434-193X
    Keywords: Ruthenium ; Ring-closing metathesis ; Metathesis ; EPC synthesis ; 1,2-Diaminocyclohex-4-ene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiopure (1R,2R)-1,2-diaminocyclohex-4-ene derivatives have been synthesized by the ruthenium-catalyzed ring-closing metathesis reaction of (4R,5R)-N,N′-bis[(S)-1-phenylethyl]-4,5-diamino-1,7-octadiene dihydrochloride.
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  • 17
    ISSN: 1434-193X
    Keywords: 1β-Methylcarbapenems ; Palladium ; Ruthenium ; Catalysis ; Cyclizations ; Stereoselective hydrogenation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -An efficient diastereoselective multi-step synthesis of bicyclic 1β-methylcarbapenem antibiotic precursors has been developed, starting from the commercially available 4-acetoxyazetidin-2-one 4. Chiral ruthenium catalysts are used in the hydrogenation step to control the β-stereochemistry at the 1-position, and a π-allylpalladium ring-closure strategy is used to form the functionalized carbapenem skeleton.
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  • 18
    ISSN: 1434-1948
    Keywords: Boranes ; Ruthenium ; Sandwich Complexes ; Diboroles ; Triple-decker ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition products of lithium alkyls and the pentaalkyl-2,3-dihydro-1,3-diborole derivatives 5a-f react with [{(C5Me5)RuCl}4] and [{(C5Me4Et)RuCl}4] to form the violet sandwich compounds 2*c-f and 2∧c, f. These formally 16 VE complexes are in fact electron-poor 18 VE species, because a high-lying combination of σ(B-C) orbitals interacts with the dxz orbital of the Ru atom. Addition of tert-butyl isocyanide to 2*a, or 2*d leads to the isonitrile complexes 6*a, and 6*d, as indicated by the spectroscopic data and X-ray structure analyses. At low temperature the interaction of 2*a, c, or e with H2 yields the classic dihydride complexes 7*a, c, and e, respectively, which have been studied by NMR. Oxidative addition of H3B·THF to the ruthenium atom of 2*a or c, followed by a reductive elimination of H2 and migration of the boranediyl group gives the yellow closo-RuC3B3 ruthenacarboranes 8*a and 8*c, respectively. The reaction of [(C2H4)2RhCl]2 and 2*c generates the tetranuclear complex 9*c.
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  • 19
    ISSN: 1434-1948
    Keywords: Cluster compounds ; Ruthenium ; Iridium ; Alkynes ; Butterfly structures ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tetrahedral cluster anion [Ru3Ir(CO)13]- (1) reacts with internal alkynes RC≡CR′ to afford the alkyne derivatives [Ru3Ir(CO)11(RCCR′)]-(2: R = R′ = Ph; 3: R = R′ = Et; 4: R = Ph; R′ = Me; 5: R = R′ = Me) which have a butterfly arrangement of the Ru3Ir skeleton in which the alkyne is coordinated in a μ4-η2 fashion. Under CO pressure they undergo fragmentation to give the trinuclear cluster anions [Ru2Ir(CO)9(RCCR′)]- (6: R = R′ = Ph; 7: R = R′ = Et; 8: R = Ph; R′ = Me; 9: R = R′ = Me), in which the alkyne ligand is coordinated in a μ3-η2 parallel fashion. Protonation of these trinuclear anions leads to the formation of the corresponding neutral hydrido clusters [HRu2Ir(CO)9(RC≡CR′)] (10: R = R′ = Ph; 11: R = R′ = Et; 12: R = Ph; R′ = Me; 13: R = R′ = Me). The protonation of the butterfly anions 2 and 3, however, gives rise to the formation of the neutral tetrahedral clusters [HRu3Ir(CO)11(RCCR′)] (14: R = R′ = Ph and 15: R = R′ = Et), respectively. The analogous clusters [HRu3Ir(CO)11(PhCCCH3)] (16) and [HRu3Ir(CO)11(CH3CCCH3)] (17) are only accessible from the reaction of the neutral cluster [HRu3Ir(CO)13] with the corresponding alkynes. The complexes 2, 4, 5, 6, 10, 12 and 15 are characterised by X-ray structure analysis.
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  • 20
    ISSN: 1434-1948
    Keywords: Biaryls ; Lactones ; Nucleophilic additions ; Ruthenium ; S ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The substitution-labile thiophene complex [CpRu{(S,S)-CHIRAPHOS}(SC4H4)]BF4 (2) [(S,S)-CHIRAPHOS = (2S,3S)bis(diphenylphosphanyl)butane], prepared from [CpRu{(S,S)-CHIRAPHOS}Cl] (1), thiophene, and AgBF4, reacted with the biaryl-thionolactones 3a-f to give the corresponding S-coordinated complexes 4a-f in high yields. The structure of 4c, which crystallized as the pure (S,S,P) diastereoisomer, was determined by X-ray crystallography. Coordination of the ruthenium fragment caused an elongation of the C=S bond, a contraction of the C-O bond within the lactone ring and a flattening of that ring. Single hydride transfer with LiBEt3H converted 4a-f into the thiolactolate complexes 5a-f in good yields and diastereoselectivities. An X-ray structure determination of the major isomer of 5a revealed it to be the (S,S,S,P) diastereoisomer. Protonation with NH4PF6 converted 5a-f into the corresponding ring-opened thioaldehyde complexes 6a-f. Alkylation of 5a with methyl iodide resulted in Ru-S cleavage to give the oxothioacetal 7a and [CpRu{(S,S)-CHIRAPHOS}I] (8). Full reduction of 4a-f with LiAlH4 produced the thiolate complexes 9a-f in high yields and 6-74% de. Methylation at sulfur converted 9a-c into the corresponding thioether complexes 10a-c, which were cleaved to 8 and the free methyl thioethers 11a-c without isomerization of the biaryl axis.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2121-2126 
    ISSN: 1434-1948
    Keywords: Ruthenium ; Allenylidene complexes ; Butadiyne ; Electrochemistry ; Thio-Claisen rearrangements ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ruthenium-butatrienylidene cations trans-[Cl(L2)2Ru=C=C=C=CH2]+ are key intermediates in the synthesis of the first thioallenylidene complexes trans-[Cl(L2)2Ru=C=C=C(SR)R′]+ (L2 = dppm, R = Et, R′ = Me: 3a, L2 = dppm, R = Me, R′ = C4H7: 3b, L2 = dppe, R = C3H5, R′ = C4H7: 3c). Spectroscopic and electrochemical data for 3a-c are presented and are compared with those of their aminoallenylidene analogues. Aminoallenylidene complexes are best represented by the iminiumalkynyl resonance form, while a true cumulene description is much more appropriate for thioallenylidene complexes 3a-c. Based on a combination of spectroscopic and electrochemical data, we present evidence that the NMR shifts of the carbon atoms of the unsaturated ligand in these allenylidene complexes are correlated to the HOMO-LUMO gap. In situ EPR-, UV/Vis-, and IR-spectro-electrochemistry reveals that the one-electron oxidation occurs at the metal center, while reduction occurs at the carbon-heteroatom terminus.
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  • 22
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 917-930 
    ISSN: 1434-1948
    Keywords: Halides ; Homogeneous catalysis ; Organometallics ; Ruthenium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: While the primary motivation of fundamental studies on carbonylhalotriruthenium complexes was to understand the promoter effect of halides on certain ruthenium-based catalytic systems of industrial relevance, such complexes have gained significance in their own right due to their remarkable ability to provide low-activation energy pathways for the coordination of organic substrates. Limitations inherent to the fragility of these prototypes led to the design and development of a related family of more sophisticated derivatives where an aminopyridyl group serves as an alternate hemilabile ancillary ligand. Studies of their reactivity have revealed the possibility of achieving a number of stoichiometric or moderately catalytic “cluster-mediated” transformations of organic substrates under very mild conditions. Yet, the viability of these systems is still limited to a narrow low-energy domain. By contrast, halotriruthenium derivatives are still seen to function as catalyst precursors under the actual conditions of certain catalytic reactions where they act as sources of ruthenium(II) halide complexes that become the active components of the system. The second part of the review focuses on novel aspects of their fascinating chemistry.
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  • 23
    ISSN: 1434-1948
    Keywords: Ruthenium ; Osmium ; Phosphane-thiolate ligands ; C-P bond activation ; C-S bond activation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-(Diphenylphosphanyl)thiophenol (HSC6H4PPh2) reacts with the carbonyl clusters [Ru3(CO)12] and [Os3(CO)10(MeCN)2] to give mixtures of products, the composition of which depends upon the reaction conditions and the ratio of the reactants. The derivatives [M3(μ-H)(μ-η2-SC6H4PPh2)(CO)9] (1a: M = Ru; 1b: M = Os), [Ru3(μ3-S)(μ-η2-Ph)(μ-PPh2)(PPh3)(CO)6] (2), and [Ru2(μ-η2-SC6H4PPh2)2(CO)4] (3) have been isolated. The SC6H4PPh2 ligand of compounds 1a and 1b has the sulfur atom spanning the same M-M edge as the hydride ligand and the phosphorus atom attached to one of the bridged metal atoms. Compound 2, which contains sulfide, phenyl, diphenylphosphanyl and triphenylphosphane ligands that arise from HSC6H4PPh2, has the Ru3 triangle capped by the sulfide and two Ru-Ru edges spanned by bridging phenyl and diphenylphosphanyl ligands. In complex 3, the two SC6H4PPh2 ligands have the same coordination behavior as in 1a or 1b; this binuclear complex is more conveniently prepared by treating [Ru2(μ-η2-MeCO2)2(CO)4(MeCN)2] with HSC6H4PPh2.
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