In Silico Design of Heteroaromatic Half-Sandwich RhI Catalysts for Acetylene [2+2+2] Cyclotrimerization: Evidence of a Reverse Indenyl Effect

Authors

  • Dr. Laura Orian,

    Corresponding author
    1. Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35129 Padova (Italy)
    • Laura Orian, Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35129 Padova (Italy)

      F. Matthias Bickelhaupt, Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam (The Netherlands)

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  • Lando P. Wolters,

    1. Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam (The Netherlands)
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  • Prof. Dr. F. Matthias Bickelhaupt

    Corresponding author
    1. Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam (The Netherlands)
    2. Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen (The Netherlands)
    • Laura Orian, Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35129 Padova (Italy)

      F. Matthias Bickelhaupt, Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam (The Netherlands)

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Abstract

A mechanistic density functional theory study of acetylene [2+2+2] cyclotrimerization to benzene catalyzed by RhI half metallocenes is presented. The catalyst fragment contains a heteroaromatic ligand, that is, the 1,2-azaborolyl (Ab) or the 3a,7a-azaborindenyl (Abi) anions, which are isostructural and isoelectronic to the hydrocarbon cyclopentadienyl (Cp) and indenyl (Ind) anions, respectively, but differ from the last ones on having two adjacent carbon atoms replaced with a boron and a nitrogen atom. The better performance of either the classic hydrocarbon or the heteroaromatic catalysts is found to depend on the different mechanistic paths that can be envisioned for the process. The present analyses uncover and explain general structure–reactivity relationships that may serve as rational design principles. In particular, we provide evidence of a reverse indenyl effect.

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