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  • 1
    ISSN: 0009-2940
    Keywords: Phosphametallacyclopropanes ; Isolobal building blocks ; Lewis basic behavior ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal-Containing Heterocycles: Preparation, Properties, Reactions, LXXVII. - Synthesis, Structure and Reactivity of Phosphametallacyclopropanes with Isolobal ER (E = N,P,As,Sb) and Fe(CO)4 Building BlocksThe phosphidometallates \documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ Li_2 \left\{ {\left[ M \right]\dddot - PPh_2 } \right\} $\end{document} {[M] = (η5-C5H5)M-(CO)2}, resulting from the metal hydride complexes H[M]PPh2H [M = Cr (1), Mo (2), W (3)] by reduction with nBuLi, react with the geminal dihalides RECl2 to give the three-membered phosphametallacyclopropanes [ER = NC6F5 (M = Cr (1a), Mo (2a), W (3a)), PPh (M = Cr (1b), Mo (2b), W (3b)), PC6H11 (M = Cr (1c), Mo (2c), W (3c)), P-tBu (M = Cr (1d), Mo (2d), W (3d)), P(2,4,6-(tBu)3C6H2) (M = Cr (1e), Mo (2e), W (3e)), As(2,4,6-(tBu)3C6H2) (M = Cr (1f), Mo (2f), W (3f)), Sb-tBu (M = Cr (1g), Mo (2g))]. Reaction of Br2Fe(CO)4 with the corresponding dilithium compounds \documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ Li_2 \left\{ {\left[ M \right]\dddot - PPh_2 } \right\} $\end{document} affords the phosphido-bridged heterodimetallic complexes . According to X-ray structural analyses in 2a and 2f the P - E bond distances are shortened while the Mo - E bonds are significantly elongated compared to a single bond. (OC)5CrTHF is added to the Lewis basic E atom in 2b, 2d, and 2g with loss of THF to give P-tBu (4d), Sb-tBu (4g)]. By this reaction the antimony-containing ring 2g is kinetically stabilized. Because of the low basicity of the N atom in 2a no addition was observed. The ring skeleton of 4b and 4g, undergoes no change by Cr(CO)5 coordination as shown by X-ray structural analyses.
    Additional Material: 2 Ill.
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  • 2
    ISSN: 0009-2940
    Keywords: Phosphamolybdacyclopropanes ; Isolobal building blocks ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal-Containing Heterocycles: Preparation, Properties, Reactions, LXIII. - Phosphamolybdacyclopropanes with Carbene and Phosphinidene Building BlocksThe phosphidomolybdate (1) {[Mo] = (η5-C5H5)Mo(CO)2} reacts with the geminal dihalides RCHCl2 (2a-c) [R = H (a), Me (b), Ph (c)] and the organophosphorus chlorides RPCl2 (4b-d) [R = 2,4,6-(tBu)3C6H2 (d)] to give the three-membered phosphamolybdacyclopropanes (3a-c) and (5b-d), respectively. The activation parameters ΔG≠ for the rotation of the P-C unit are independent of the substituent R, based on temperature-dependent 1H-NMR spectra of 3a-c. According to an X-ray structural analysis 5c crystallizes in the triclinic space group P1 with Z = 4. Compared to a single bond the P—P distance (211 pm) in 5c is shorter. the complexes (OC)5MTHF are added to the Lewis basic phosphinidene phosphorus in 5c with loss of THF giving (6c-8c) [M = Cr (6), Mo (7), W (8)].
    Notes: Das Phosphidomolybdat (1) {[Mo] = (η5-C5H5)Mo(CO)2} reagiert mit den geminalen Dihalogeniden RCHCl2 (2a-c) [R = H (a), Me (b), Ph (c)] und Organophosphorchloriden RPCl2 (4b-d) [R = 2,4,6-(tBu)3C6H2 (d)] zu den dreigliedrigen Phosphamolybdacyclopropanen (3A-c) bzw. (5b-d). Aus temperaturabhängigen 1H-NMR-Spektren von 3a-c ergeben sich die Aktivierungsparameter ΔG≠ für die Rotation der P—C-Einheit, die unabhängig vom Substituenten R sind. 5c kristallisiert laut Röntgenstruktur-analyse in der triklinen Raumgruppe P1 mit Z = 4. Der P—P-Abstand in 5c ist mit 211 pm gegenüber einer Einfachbindung verkürzt. An den Lewis-basischen Phosphiniden-Phosphor in 5c addieren sich unter THF-Verlust die Komplexe (OC)5MTHF unter Bildung von (6c-8c) [M = Cr (6), Mo (7), W (8)].
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