Chiral-at-Molybdenum – A Computational Study on N-Substituted cis-MoO2(nacnac)2

George Dhimba; Alfred Muller; Koop Lammertsma

doi:10.1002/ejic.202300256

Chiral-at-Molybdenum – A Computational Study on N-Substituted cis-MoO₂(nacnac)₂

George Dhimba, Alfred Muller, Koop Lammertsma

Chemical Sciences

Research output: Contribution to journal › Article › peer-review

Abstract

Cis-MoO₂(nacnac)₂ (nacnac=β-diketiminate) can be a viable chiral-at-metal catalyst when its two β-diketiminate (nacnac) ligands are N-substituted to prevent Λ⇌Δ racemization. Even simple methyl groups raise the barriers for racemization significantly for the Bailar, Rây-Dutt, Conte-Hippler, and Dhimba-Muller-Lammertsma (DML) twists to a respectable 28.5, 37.8, 30.5, and 25.1 kcal/mol, respectively, at ωB97X-D/6-311+G(2d,p) (LANL2DZ for Mo) including acetonitrile solvation. The lowest energy DML barrier increases to ΔG^o=27.4 kcal/mol with N-substituted t-butyl groups. The nacnac ligands’ electronic and steric components to the racemization barriers are discussed.

Original language	English
Article number	e202300256
Journal	European Journal of Inorganic Chemistry
Volume	26
Issue number	25
DOIs	https://doi.org/10.1002/ejic.202300256
Publication status	Published - 1 Sept 2023

Keywords

N,N-ligands
coordination modes
density functional calculations
homogeneous catalysis
molybdenum

ASJC Scopus subject areas

Inorganic Chemistry

Access to Document

10.1002/ejic.202300256

Cite this

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title = "Chiral-at-Molybdenum – A Computational Study on N-Substituted cis-MoO2(nacnac)2",

abstract = "Cis-MoO2(nacnac)2 (nacnac=β-diketiminate) can be a viable chiral-at-metal catalyst when its two β-diketiminate (nacnac) ligands are N-substituted to prevent Λ⇌Δ racemization. Even simple methyl groups raise the barriers for racemization significantly for the Bailar, R{\^a}y-Dutt, Conte-Hippler, and Dhimba-Muller-Lammertsma (DML) twists to a respectable 28.5, 37.8, 30.5, and 25.1 kcal/mol, respectively, at ωB97X-D/6-311+G(2d,p) (LANL2DZ for Mo) including acetonitrile solvation. The lowest energy DML barrier increases to ΔGo=27.4 kcal/mol with N-substituted t-butyl groups. The nacnac ligands{\textquoteright} electronic and steric components to the racemization barriers are discussed.",

keywords = "N,N-ligands, coordination modes, density functional calculations, homogeneous catalysis, molybdenum",

author = "George Dhimba and Alfred Muller and Koop Lammertsma",

note = "Publisher Copyright: {\textcopyright} 2023 The Authors. European Journal of Inorganic Chemistry published by Wiley-VCH GmbH.",

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N2 - Cis-MoO2(nacnac)2 (nacnac=β-diketiminate) can be a viable chiral-at-metal catalyst when its two β-diketiminate (nacnac) ligands are N-substituted to prevent Λ⇌Δ racemization. Even simple methyl groups raise the barriers for racemization significantly for the Bailar, Rây-Dutt, Conte-Hippler, and Dhimba-Muller-Lammertsma (DML) twists to a respectable 28.5, 37.8, 30.5, and 25.1 kcal/mol, respectively, at ωB97X-D/6-311+G(2d,p) (LANL2DZ for Mo) including acetonitrile solvation. The lowest energy DML barrier increases to ΔGo=27.4 kcal/mol with N-substituted t-butyl groups. The nacnac ligands’ electronic and steric components to the racemization barriers are discussed.

AB - Cis-MoO2(nacnac)2 (nacnac=β-diketiminate) can be a viable chiral-at-metal catalyst when its two β-diketiminate (nacnac) ligands are N-substituted to prevent Λ⇌Δ racemization. Even simple methyl groups raise the barriers for racemization significantly for the Bailar, Rây-Dutt, Conte-Hippler, and Dhimba-Muller-Lammertsma (DML) twists to a respectable 28.5, 37.8, 30.5, and 25.1 kcal/mol, respectively, at ωB97X-D/6-311+G(2d,p) (LANL2DZ for Mo) including acetonitrile solvation. The lowest energy DML barrier increases to ΔGo=27.4 kcal/mol with N-substituted t-butyl groups. The nacnac ligands’ electronic and steric components to the racemization barriers are discussed.

KW - N,N-ligands

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