Potassium and Well-Defined Neutral and Cationic Calcium Fluoroalkoxide Complexes: Structural Features and Reactivity
| Autor: | Jean-François Carpentier, Sorin-Claudiu Roşca, Thierry Roisnel, Yann Sarazin, Vincent Dorcet |
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| Přispěvatelé: | Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2014 |
| Předmět: |
Diphenylphosphine
Stereochemistry Ligand Organic Chemistry Cationic polymerization Nuclear magnetic resonance spectroscopy Inorganic Chemistry chemistry.chemical_compound Crystallography chemistry Intramolecular force Alkoxide Saturation (graph theory) [CHIM]Chemical Sciences Reactivity (chemistry) Physical and Theoretical Chemistry |
| Zdroj: | Organometallics Organometallics, American Chemical Society, 2014, 33 (20), pp.5630-5642. ⟨10.1021/om500343w⟩ Organometallics, 2014, 33 (20), pp.5630-5642. ⟨10.1021/om500343w⟩ |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/om500343w |
| Popis: | International audience; The fluorinated aminoether alcohols (1-aza-12-crown-4)CH2C(CF3)2OH ({RO1F}H), (MeOCH2CH2)2NCH2C(CF3)2OH ({RO2F}H), and (MeOCH2CH2)(Me)NCH2C(CF3)2OH ({RO3F}H) have been synthesized and used to prepare the heteroleptic calcium amido complexes {ROxF}Ca(N(SiMe2R)2) (4–7; x = 2, 3, R = H, Me). The ability to form stable complexes varies with the chelating and electron-donating ability of the aminoether alkoxide ligand, as exemplified by our failure to isolate cleanly the elusive {RO1F}Ca(N(SiMe2R)2). X-ray diffraction studies show that, in the solid state, intramolecular Ca···F interactions help reach coordinative saturation in the dimeric [{RO2F}Ca(N(SiMe3)2)]2 ([4]2), [{RO2F}Ca(N(SiMe2H)2)]2 ([5]2), [{RO3F}Ca(N(SiMe3)2)]2 ([6]2), and [{RO3F}Ca(N(SiMe2H)2)]2 ([7]2), which crystallized free of solvent coligands. Similar stabilizing K···F patterns were found in the polymetallic potassium fluoroalkoxides [{RO1F}K]2 ([1]2), [{RO2F}K]4 ([2]4), and [{RO3F}K]4 ([3]4); [2]4 and [3]4 form heterocubanes in the solid state. Examination of the XRD data for [1]2–[7]2 shows that metal···F interactions can be favored over binding of Oether atoms for calcium and potassium. Pulse-gradient spin–echo NMR spectroscopy shows that the complexes remain aggregated in aromatic solvents. The solvent-free salts [{ROxF}Ca+]·[H2N{B(C6F5)3}2–] (x = 1 (8), 2 (9), 3 (10)) are obtained by treating 4–7 with [H(OEt2)2+]·[H2N{B(C6F5)3}2–] or by reacting Ca(N(SiMe3)2)2 with [{ROxF}HH+]·[H2N{B(C6F5)3}2–]; the solid-state structures of [8·H2O]2 and [9·H2O]2 again showed the presence of Ca···F contacts. Complexes 5–7 are promising catalysts for the regiospecific anti-Markovnikov hydrophosphination of styrene with diphenylphosphine, affording TOF values as high as 52 molsubst molCa–1 h–1 with up to 400 equiv of substrates within 1–2 h at 60 °C. |
| Databáze: | OpenAIRE |
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