Chiral‐at‐Molybdenum – A Computational Study on N‐Substituted cis‐MoO 2 (nacnac) 2

• Published in: European Journal of Inorganic Chemistry
• Main Authors: Dhimba, George, Muller, Alfred, Lammertsma, Koop
• Other Authors: National Research Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: DML
• Online Access: http://dx.doi.org/10.1002/ejic.202300256

Abstract Cis‐MoO 2 (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.