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Nucleophilic Nickel and Palladium Pincer Hydroxides: A Study of Their Reactions with Dimethyl Carbonate and Other Non‐Alkylating Organic Electrophiles
Author(s) -
MartínezPrieto Luis M.,
Río Diego,
Álvarez Eleuterio,
Palma Pilar,
Cámpora Juan
Publication year - 2021
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202100400
Subject(s) - chemistry , electrophile , dimethyl carbonate , nucleophile , pincer movement , hydroxide , palladium , substituent , medicinal chemistry , methanol , benzaldehyde , adduct , reductive elimination , organic chemistry , catalysis
The reactions of the pincer hydroxide complexes [( iPr PCP)M(OH)] (M=Ni, Pd) with dimethyl carbonate (DMC), and a set of organic electrophiles including benzaldehyde have been investigated in the context of our ongoing investigation on the synthesis of alkyl carbonates from CO 2 and alcohols. The final outcome of such reactions is diverse, but for PhCHO and DMC the first step is a mechanistically similar addition of the [M]−OH linkage across the carbonyl functionality, that leads to unstable adducts. DMC is cleaved irreversibly by both Ni and Pd hydroxides, affording the corresponding methylcarbonates [( iPr PCP)MOCO 2 Me] and methanol, whereas PhCHO affords benzoate complexes [[( iPr PCP)MOCO 2 Ph]. The main kinetic and thermodynamic features of these reactions were reproduced satisfactorily by computational DFT models. The calculations throw light on the true causes of irreversibility of DMC cleavage by nucleophilic hydroxide complexes, which is the primary cause that prevents methanol carboxylation from being catalysed by the Ni or Pd pincers.