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Chiral NHC-Complexes with Dioxolane Backbone Heterogenized on MCM-41. Catalytic Activity

Authors

  • Gonzalo Villaverde,

    1. Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid (Spain), Fax: (+34) 913720623
    2. Instituto de Química Orgánica, CSIC, C/Juan de la Cierva 3, 28006 Madrid (Spain), Fax: (+34) 915644853
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  • Prof. Avelino Corma,

    Corresponding author
    1. Instituto de Tecnología Química, CSIC, Avda los Naranjos, s/n, 46022 Valencia (Spain), Fax: (+34) 963877809
    • Avelino Corma, Instituto de Tecnología Química, CSIC, Avda los Naranjos, s/n, 46022 Valencia (Spain), Fax: (+34) 963877809

      Marta Iglesias, Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid (Spain), Fax: (+34) 913720623

      Félix Sánchez, Instituto de Química Orgánica, CSIC, C/Juan de la Cierva 3, 28006 Madrid (Spain), Fax: (+34) 915644853

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  • Prof. Marta Iglesias,

    Corresponding author
    1. Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid (Spain), Fax: (+34) 913720623
    • Avelino Corma, Instituto de Tecnología Química, CSIC, Avda los Naranjos, s/n, 46022 Valencia (Spain), Fax: (+34) 963877809

      Marta Iglesias, Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid (Spain), Fax: (+34) 913720623

      Félix Sánchez, Instituto de Química Orgánica, CSIC, C/Juan de la Cierva 3, 28006 Madrid (Spain), Fax: (+34) 915644853

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  • Prof. Félix Sánchez

    Corresponding author
    1. Instituto de Química Orgánica, CSIC, C/Juan de la Cierva 3, 28006 Madrid (Spain), Fax: (+34) 915644853
    • Avelino Corma, Instituto de Tecnología Química, CSIC, Avda los Naranjos, s/n, 46022 Valencia (Spain), Fax: (+34) 963877809

      Marta Iglesias, Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid (Spain), Fax: (+34) 913720623

      Félix Sánchez, Instituto de Química Orgánica, CSIC, C/Juan de la Cierva 3, 28006 Madrid (Spain), Fax: (+34) 915644853

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Abstract

Rhodium, palladium, and gold complexes of chiral (NHC)–dioxolane–amino ligands were prepared. Herein, new methods for the heterogenization of NHC-chiral complexes on porous silica supports are demonstrated for the facile recovery and recycling of these expensive catalysts. Activity, selectivity, and recyclability were investigated and compared to that of the analogous homogeneous catalysts for asymmetric hydrogenation reactions. The compounds were characterized by using a variety of methods, including solid state cross-polarization magic-angle spinning (CP MAS) 13C NMR, FT-IR spectroscopy, and elemental analysis. Heterogenized rhodium(I) and palladium(II) catalysts could be used at least four times without loss of activity or enantioselectivity. (NHC)–gold(I) complexes were easily immobilized and recycled by a treatment with benzonitrile during the washing steps between cycles. This washing maintained the activity and enantioselectivity.

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