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  • 1
    ISSN: 0009-2940
    Keywords: CH Acidity ; Rhenium complexes ; Allylidene ; Butatriene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-CH Acidity of Allylidene Complexes: Organorhenium Derivatives of 1,2,3-Butatriene by Dehydrochlorination of Rhena(V) Allylidenes. Synthesis and StructureThe rhena(V) allylidene complex (η5-C5Me5)ReCl2 [η1:η3-(CH3)-CC(Cl)CH2] (2) is quantitatively converted into the novel organorhenium 1,2,3-butatriene derivative (η5-C5Me5)ReCl2[η3-H2CC(C5H5N)CCH2] (3) by lithium hydroxide in the presence of excess pyridine. This result shows so far not investigated CH acidity of methyl groups, that are substituting π-bonded allylidene frameworks at the α-position. According to an X-ray structure analysis, the coordination geometry of the 1,2,3-butatriene ligand is very similar to related allyl complexes of the (η5-C5Me5)ReCl2 fragment.
    Notes: Der Rhena(V)-allyliden-Komplex (η5-C5Me5)ReCl2 [η1:η3-(CH3)-CC(Cl)CH2] (2) wird durch Lithiumhydroxid in Gegenwart von überschüssigem Pyridin quantitativ zu dem neuartigen rhenium-organischen 1,2,3-Butatrien-Derivat (η5-C5Me5)ReCl2[η3-H2CC(C5H5N)CCH2] (3) dehydrohalogeniert. Dieses Ergebnis weist auf die bisher nicht beachtete CH-Acidität von Methylgruppen hin, die ein π-gebundenes Allyliden-Gerüst α-ständig substituieren. Einer Röntgenstrukturanalyse zufolge ist der von 1,2,3-Butatrien abgeleitete Ligand allylartig an das (η5-C5Me5)ReCl2-Fragment gebunden.
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1795-1799 
    ISSN: 0009-2940
    Keywords: Carbonyl complexes ; Rhenium complexes ; Alkoxy carbene, structure of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Carbonyl Syntheses, XXI. - Straightforward Synthesis of a Synthetically Useful Alkoxy(carbonyl)metallateAnionic methoxy complexes are formed upon carbonylation of ammonium perrhenate in methanol at 230-240°C. Thus, the dinuclear ionic complex [N(CH3)4][Re2(CO)6(μ-OCH3)3] (2) results in 80% yield at CO pressures of ca. 100 bar, while the trinuclear derivative [N(CH3)4][Re3(CO)9(μ3-OCH3)3(μ3-OCH3)] (3) is due to lower pressure conditions (ca. 50 bar); 2 yields the bis(carbene) complex 4 of formula fac-Re(CO)3L2I upon treatment with a bis(imidazolium) iodide, thus demonstrating that carbonylrhenium chemistry not necessarily depends on the availability of Re2(CO)10.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1971-1974 
    ISSN: 0009-2940
    Keywords: Alkylidyne ligands ; Rhenium complexes ; Metal-metal multiple bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiple Bonds Between Main-Group Elements and Transition Metals, LXXXII.  -  Dinuclear p-Benzylidyne Complexes Having a Double Bond between Rhenium AtomsThe dialkylrhenium(V) complex (η5-C5Me5)Re(=O)(CH2Ph)2 (3) reacts with the organotitanium reagents (η5-C5H5)TiX3 (X = Cl, Br) to yield the dinuclear rhenium(IV) complexes (η5C5Me5)2 Re2X3(CC6H5) (4a, b). According to a single-crystal X-ray diffraction analysis, 4a′ (C5Me4Et in place of C5Me5) represents one of the few known examples of μ-alkylidyne complexes that have metal-to-metal multiple bonds. The molecule of C2 symmetry has a planar four-membered Re,Cl,Re′,C-ring geometry and two trans-oriented sets of ligands. Very small angles at the bridging chloro ligand and alkylidyne carbon atom result from the short metal-metal distance (double bond).
    Additional Material: 1 Ill.
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  • 4
    ISSN: 0044-2313
    Keywords: Rhenium complexes ; carbonyl complexes ; nitrosyl complexes ; heptamethylindene ; crystal structures ; σ/η-bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Metal Carbonyls. 23. Crystal Structure and Reactivity of Heptamethylindenyl Carbonyl Metal ComplexesReaction of heptamethylindene (C9(CH3)7, 1) with Re2(CO)10 yields [η5-C9(CH3)7]Re(CO)3 (2), which reacts with NO+BF4- to form the cationic complex [{η5-C9(CH3)7}Re(CO)2NO]+BF4- (3). Irradiation of 2 with UV light in the presence of triethyl phosphite leads to formation of [η5-C9(CH3)7]Re(CO)2[P(OC2H5)3] (4). Alkylation of (CH3)3SnCl with Ind*Li gives [η1-C9(CH3)7]Sn(CH3)3 (5). All compounds were characterized by spectroscopic methods. The molecular structures of 3 and 5 were determined by single crystal X-ray diffraction (3: P21/n (14), a = 1497.7(4) pm, b = 879.0(2) pm, c = 1609.0(4) pm and β = 110.99(2)°, R1 = 0.038, wR2 = 0.080; 5: P21/n (14), a = 726.1(1) pm, b = 2930.7(3) pm, c = 930.0(1) pm and β = 112.834(5)°, R1 = 0.044, Rw = 0.048). Complexes 2-4 exhibit a piano stool configuration with a η5-coordinated permethylindenyl ligand (Ind*). Compound 5 displays a η1 -coordination of the Ind* ligand. Temperature enhancement causes a hapticity change, as observed by NMR spectroscopy.
    Notes: Heptamethylinden (C9(CH3)7H, 1) reagiert mit Re2(CO)10 zu [η5-C9(CH3)7]Re(CO)3 (2), das durch Umsetzung mit NO+BF4- die kationische Verbindung[{η5-C9(CH3)7}Re (CO)2NO]+BF4- (3) und unter Bestrahlung mit UV-Licht in Anwesenheit von Triethylphosphit [η5-C9(CH3)7]Re(CO)2[P(OC2H5)3] (4) ergibt. Durch Alkylierung von (CH3)3SnCl wird [η1-C9(CH3)7]Sn(CH3)3 (5) erhalten. Alle Verbindungen wurden mit spektroskopischen Methoden vollständig charakterisiert. Von 3 und 5 wurden die Kristallstrukturen röntgenstrukturanalytisch bestimmt (3: P21/n (14), a = 1497.7(4) pm, b = 879.0(2) pm, c = 1609.0(4) pm und β = 110.99(2)°, R1 = 0.038, wR2 = 0.080; 5: P21/n (14), a = 726.1(1) pm, b = 2930.7(3) pm, c = 930.0(1) pm und β = 112.834(5)°, R1 = 0.044, Rw = 0.048). Während bei den Komplexen 2-4 der Heptamethylindenligand (Ind*) einen Halbsandwich-Komplex bildet (η5-Bindung zum Metall), so liegt in Derivat 5 erwartungsgemäß eine σ-Bindung zwischen einem C-Atom des Ind*-Liganden und dem Metallzentrum vor. Bei Temperaturerhöhung tritt eine Änderung der Haptizitätsverhältnisse ein (NMR-Evidenz).
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