Palladium pincer complexes featuring an unsymmetrical SCN indene-based ligand with an hemilabile pyridine sidearm

Paul Brunel (1) , Chloé Lhardy , Sonia Mallet-Ladeira (2) , Julien Monot , Blanca Martin-Vaca (1) , Didier Bourissou (1)

1 LHFA - Laboratoire Hétérochimie Fondamentale et Appliquée
2 LCC - Laboratoire de chimie de coordination

The new unsymmetrical indene-based pro-ligand featuring thiophosphinoyle and methylpyridine sidearms 2 was prepared. Coordination and cyclometalation in the presence of [PdCl2(PhCN)2] and PS-DIEA afforded three well-defined 2-indenyl SCN pincer complexes 3a-c. The lability of the pyridine moiety has been evidenced upon treatment with triphenylphosphine and 2,6-dimethylphenylisocyanide. In addition, reversible C-Pd bond cleavage has been demonstrated under Brönsted acid/base conditions. The indenediide SCN pincer complex 4 was prepared by deprotonation of 3a in the presence of triphenylphosphine. Preliminary catalytic tests on the cyloisomerization of 4-pentynoic acid have underlined the impact of the pyridine sidearm on catalytic activity.

Domaines: Chimie

Paul Brunel, Chloé Lhardy, Sonia Mallet-Ladeira, Julien Monot, Blanca Martin-Vaca, et al.. Palladium pincer complexes featuring an unsymmetrical SCN indene-based ligand with an hemilabile pyridine sidearm. Dalton Transactions, 2019, 48 (26), pp.9801-9806. ⟨10.1039/C9DT00898E⟩. ⟨hal-02398806⟩