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  • Articles  (5)
  • Cyclocotrimerization  (3)
  • Supramolecular chemistry  (2)
  • 1
    ISSN: 0009-2940
    Keywords: Cyclocotrimerization ; Selenophosphinites ; Alkynes, activated ; Selenophenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Selenophosphinito complexes (OC)4Mn(η2-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PR21) (2a, b) [R1 = cyc-Hex (a), tBu (b)] are formed by the reaction of BrMn(CO)5 with the phosphane selenides R21HPSe (1a, b) in the presence of the auxiliary base Et(iPr)2N. According to an X-ray structural analysis, 2a crystallizes in the space group \documentclass{article}\pagestyle{empty}\begin{document}$ P\bar 1 $\end{document} with Z = 2. The dimeric complex [(OC)4Mn(μ-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PMe2)]2 (4c) is not obtained in a straightforward way. Compound 4c is only obtained via the intermediate Br(OC)4Mn-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}P(H)Me2 (3c) by HBr elimination with nBuLi. Complex 3c is formed by replacement of carbon monoxide in BrMn(CO)5 by Me2HPSe (1c). A dissociative equilibrium between [(OC)4 Mn(μ-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PMe2)]2 (4c) and the monomeric species (OC)4Mn(\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}2-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PMe2) was not observed. The cyclocotrimerization of the 〉P\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}Se function with the activated alkynes ZC≡CZ [Z = CO2R2; R2 = Me (d), Et (e), iPr (f), cyc-Hex (g)] was successful only in the case of the cyclohexyl derivative 2a to give the selenaphosphamanganabicycloheptadienes 5d - g. An X-ray structural analysis proved that 5d crystallizes in the space group \documentclass{article}\pagestyle{empty}\begin{document}$ P\bar 1 $\end{document} with Z = 2. Under CO pressure 5d was degraded to the selenophene 6.
    Additional Material: 2 Ill.
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  • 2
    ISSN: 0009-2940
    Keywords: Cyclocotrimerization ; Furan derivatives ; η2-Thiophosphinito complexes of cobalt ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal-Containing Heterocycles: Preparation, Properties, Reaction, LXI. - The Behavior of η-Thiophosphinito Complexes of Cabalt towards Electron-Poor AlkynesIn the presence of PPh3, the (η2-thiophosphinito)cobalt complex Ph3P[cO](η-S=2)[Co] = Co(Co)2 reacts with the alkynes R′C≡CR′ (2a-d) [R′ = CO2R: R = Me (a), Et (b), iPr (c), Cy (d)] to give the thiaphosphacobaltacyclopentadienes . According to an X-ray structural analysis, 3b crystallizes in the space group P1 with Z = 2. In the planar five-membered ring cobalt has a trigonal bipyramidal geometry. The furan derivative 7a is obtained from 3a and 2a by hydrolytic decomposition of the nonisolable cyclotrimerisation product 6a. Furan 7a is formed also straightforwardly by the reaction of 1 with excess of 2a in the absence of PPh3. The reaction of 3b with the mixed substituted alkyne CH3C≡CCO2CH3 (2e) affords the isomeric furan derivatives 8 and 9.
    Notes: In Gegenwart von PPh3 setzt sich der (η2-Thiophosphinito)cobalt-Komplex Ph3P[cO](η-S=2)[Co] = Co(Co)2 mit den Alkinen R′C≡CR′ (2a-d) [R′ = CO2R: R = Me (a), Et (b), iPr (c), Cy (d)] zu den Thiaphosphacobaltacyclopentadienen Ph3 um. Nach einer Röntgenstrukturanalyse kristallisiert 3b in der Raumgruppe P1 mit Z = 2. In dem planaren Fünfring besitzt Cobalt eine trigonalbipyramidale Geometrie. Aus 3a und 2a erhält man über das nicht isolierbare Cyclotrimerisat 6a durch dessen hydrolytischen Abbau und Umlagerung das Furanderivat 7a, welches bei Abwesenheit von PPh3 auch direkt durch Reaktion von 1 mit überschüssigem 2a entsteht. Die Umsetzung von 3b mit dem gemischt substituierten Alkin CH3C≡CCO2CH3 (2e) liefert die isomeren Furanderivate 8 und 9.
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  • 3
    ISSN: 0009-2940
    Keywords: Cyclocotrimerization ; Regioselectivity ; Thiophene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal-Containing Heterocycles: Preparation, Properties, Reactions, LXXVI. - Regioselective Cyclocotrimerization of a Thiophosphinito Unit with Methyl PropynoateThe P = S function of (η2-PCy2=S)Mn(CO)4 (1) undergoes a regiospecific cyclocotrimerization with methyl propynoate to give the bicyclic compound 3. Oxidation of 3 with (NH4)2[Ce(NO3)6] results in the formation of the thiophene 4. Compound 3 was characterized on the basis of MS, IR, 31P{1H}-, 1H-, 13C{1H}-NMR spectra and with a 2D-H,C-COSY experiment.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 959-969 
    ISSN: 1434-1948
    Keywords: Bipyridyldiphosphane ligands ; Macrocycles ; Metallacyclophanes ; Platinum ; Supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 5,5′-bis(hydroxyalkyl)-2,2′-bipyridines 4a-c (Scheme 1) were prepared either in one step (4b, 4c) or in four steps (4a) starting with 5,5′-dimethyl-2,2′-bipyridine in each case. Reaction of 4a-c with mesyl chloride afforded the bis(mesylates) [-C5H3N-(CH2)n-CH2-OSO2Me]2 5a-c [n = 1 (a), 2 (b), 3 (c)], which could easily be transformed into the diphosphanes 6a-c by reaction with LiPPh2. Treatment of 6c, 6b with Cl2Pt(NCPh)2 and (RC6H4)2Pt(COD) according to the high-dilution method resulted in the formation of the tetraphosphadiplatinacyclophanes [-C5H3N-(CH2)4-PPh2PtCl2PPh2-(CH2)4-C5H3N-]2 (7c) and [-C5H3N-(CH2)3-PPh2Pt(C6H4R)2PPh2-(CH2)3-C5H3N-]2 (8b, 9b) (8b: R = H, 9b: R = tBu), respectively (Scheme 2). The molecular structures of 8b and 9b were elucidated by X-ray structural analyses. The noncoordinated bipyridine moieties in 8b were employed to encapsulate copper(I) to give the host/guest complex 10b (Scheme 3), which was investigated by FAB-MS, NMR spectroscopy, and cyclovoltammetry. 10b exhibited a quasi-reversible oxidation at E1/2 = -0.31 V and an electrodeposition-redissolution redox system at E1/2 = -0.79 V, owing to the formation of copper at the surface of the working electrode.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 679-685 
    ISSN: 1434-1948
    Keywords: Cage compounds ; Metallacyclophanes ; P ligands ; Platinum ; Supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the tris(triflate) 4 (Scheme 1) has been achieved by means of a straightforward three-step reaction sequence. After initial lithiation of mesitylene, treatment of the obtained trilithium compound C6H3(CH2Li)3 (2) with oxirane results in the formation of 1,3,5-tris(3-hydroxypropyl)benzene (3), which is then transformed to 4 by reaction with (CF3SO2)2O in the presence of pyridine. Whereas 4 reacts with Na2[Os(CO)4] in a somewhat complicated manner, similar reactions with Na[Re(CO)5] and LiPPh2 give the hydrocarbon-bridged tris(rhenium) complex C6H3[(CH2)3Re(CO)5]3 (5) and the tris(phosphane) C6H3[(CH2)3PPh2]3 (6), respectively. Employing the high-dilution method, from 6 and Cl2Pt(NCPh)2 the nanoscaled tri- and hexaplatinacyclophanes 7 and 9 are available. Owing to the optimal geometry and flexibility of the cage in 7, 1,2-dichloroethane can be reversibly encapsulated. The molecular structure of 7 · 7 1,2-Cl2C2H4 was determined by an X-ray structure analysis. The utility of the reactive metal centers in 7 has been demonstrated by replacing the chloro ligands by acetonitrile to give the cationic platinacyclophane 8, in which, according to NMR studies, the cage-like structure is preserved.
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