Ligand–Metal Cooperation in PCP Pincer Complexes: Rational Design and Catalytic Activity in Acceptorless Dehydrogenation of Alcohols

Abstract

A helping hand: The dibenzobarrelene‐based PC sp 3P pincer complex 1 was designed as a bifunctional catalyst for the acceptorless dehydrogenation of alcohols. The mechanism of the H2 release involves interaction between the hydride ligand and the acidic sidearm in the intermediate 2 (red O, yellow Cl, green P, blue Ir). The feasibility of the complete catalytic cycle was studied using a stoichiometric model and the reaction was subsequently realized in a catalytic fashion.

New PC(sp3)P pincer complexes of platinum and palladium

“…Moreover, they proved themself as highly active catalysts for the transfer hydrogenation of ketones [12], as well as transfer [16] and acceptorless dehydrogenation of alcohols [17].…”

Optimum bifunctionality in a 2-(2-pyridyl-2-ol)-1,10-phenanthroline based ruthenium complex for transfer hydrogenation of ketones and nitriles: impact of the number of 2-hydroxypyridine fragments

“…9,10 Due to metal-ligand cooperativity, these complexes enhance the rate of the reaction significantly and were extensively pursued for numerous chemical transformations. [26][27][28][29][30][31][32] 2-Hydroxypyridine (2-HP) based ligands have emerged as an exciting class of bifunctional ligands as they can exist in both tautomeric forms depending on the reaction conditions (Scheme 1). [26][27][28][29][30][31][32] 2-Hydroxypyridine (2-HP) based ligands have emerged as an exciting class of bifunctional ligands as they can exist in both tautomeric forms depending on the reaction conditions (Scheme 1).…”

Oxidation and Reduction

“…The feasibility of the complete catalytic cycle was studied using a stoichiometric model. 287 The reagent (138), for photolabile carbonyl group protection, oxidized carbonyl compounds R 1 COR (alcohols, ethers, and esters) under mild acidic or neutral conditions to the photosensitive acetals (139). The oxidation was presumably via hydride abstraction by the tritylium ion generated from (138) under acidic conditions.…”