Hydrogen bonds, coordination isomerism, and catalytic dehydrogenation of alcohols with the bifunctional iridium pincer complex IrHCl

作者：Silantyev G A; Titova E M; Filippov O A; Gutsul E I; Gelman D; Belkova N V^*

来源：Russian Chemical Bulletin, 2015, 64(12): 2806-2810.

DOI：10.1007/s11172-015-1230-x

• transition metal hydrides
• hydrogen bonds
• NMR spectroscopy
• IR spectroscopy

The reaction of iridium(iii) hydride complex 1 based on the pincer dibenzobarrelene ligand with pyridine proceeds stepwise to show different reactivities of the starting fac-isomers 1A and 1B. The kinetic product of the reaction is mer-complex 2 with a trans disposition of the pyridine and hydride ligands. Isomerization into the thermodynamic product 2' containing pyridine in the cis-position with regard to hydride proceeds slowly. The estimation of activation parameters (Delta H (not equal) and Delta S (not equal)) shows that the change in the geometry of fac-complexes upon coordination of pyridine occurs through an associative transition state, while isomerization of the mer-complexes is a dissociative process. The isomers of complex 1 and its pyridine-containing derivatives 2 and 2' are shown to exhibit different reactivities in the formation of dihydrogen bond and the catalytic dehydrogenation of (PrOH)-O-i under model conditions.

• 出版日期2015-12