Titanocene(III) complexes with 2-phosphinoaryloxide ligands for the catalytic dehydrogenation of dimethylamine borane

Marcus Klahn; Dirk Hollmann; Anke Spannenberg; Angelika Brückner; Torsten Beweries

doi:10.1039/c5dt00275c

Titanocene(III) complexes with 2-phosphinoaryloxide ligands for the catalytic dehydrogenation of dimethylamine borane

Dalton Trans. 2015 Jul 21;44(27):12103-11. doi: 10.1039/c5dt00275c.

Authors

Marcus Klahn¹, Dirk Hollmann, Anke Spannenberg, Angelika Brückner, Torsten Beweries

Affiliation

¹ Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Str. 29a, 18059 Rostock, Germany. torsten.beweries@catalysis.de.

PMID: 25826024
DOI: 10.1039/c5dt00275c

Abstract

A study of the dehydrogenation of dimethylamine borane using different titanocene(III) complexes with 2-phosphinoaryloxide ligands is presented. Complexes Cp2Ti(κ(2)-O, P-O-C6H4-PR2) (3a: R = i-Pr, 3b: R = Ph) (Cp = η(5)-cyclopentadienyl) and Cp*2Ti(κ(1)-O-O-C6H4-PR2) (5a: R = i-Pr, 5b: R = Ph) (Cp* = η(5)-pentamethylcyclopentadienyl) were prepared by reactions of the 2-phosphinophenol ligand with different titanocene sources and fully characterised. Their catalytic activity depends on the steric influence of the cyclopentadienyl ligand, the coordination mode of the 2-phosphinoaryloxide ligand and on the used solvent. Complex 3a showed a turnover number of 43.2 in the neat substrate after 24 hours. EPR investigations were used to elucidate the fate of the Ti(III) catalyst.