Electrophilic Si−H Activation by Acetonitrilo Benzo[h]quinoline Iridacycles: Influence of Electronic Effects in Catalysis.

Autor: Behzadi, Masoumeh, Gajendramurthy, Chunchesh Malangi, Boucher, Mélanie, Deraedt, Christophe, Cornaton, Yann, Karmazin, Lydia, Gruber, Nathalie, Bertani, Philippe, Djukic, Jean‐Pierre
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Zdroj: Chemistry - A European Journal; Aug2023, Vol. 29 Issue 43, p1-17, 17p
Abstrakt: The performance of six newly synthesized benzo[h]quinoline‐derived acetonitrilo pentamethylcyclopentadienyl iridium(III) tetrakis(3,5‐bis‐trifluoromethylphenyl)borate salts bearing different substituents −X (−OMe, −H, −Cl, −Br, −NO2 and −(NO2)2) on the heterochelating ligand were evaluated in the dehydro‐O‐silylation of benzyl alcohol and the monohydrosilylation of 4‐methoxybenzonitrile by Et3SiH, two reactions involving the electrophilic activation of the Si−H bond. The benchmark shows a direct dependence of the catalytic efficiency with the electronic effect of −X, which is confirmed by theoretical assessment of the intrinsic silylicities Π of hydridoiridium(III)‐silylium adducts and by the theoretical evaluation of the propensity of hydridospecies to transfer the hydrido ligand to the activated substrate. The revisited analysis of the Ir−Si−H interactions shows that the most cohesive bond in hydridoiridium(III)‐silylium adducts is the Ir−H one, while the Ir−Si is a weak donor‐acceptor dative bond. The Si...H interaction in all the cases is noncovalent in nature and dominated by electrostatics confirming the heterolytic cleavage of the hydrosilane's Si−H bond in this key catalytically relevant species. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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