Small molecule activation by iridium complexes supported by a monoanionic NNN-pincer ligand

The synthesis of iridium 1,5-cyclooctadiene and cyclooctene complexes supported by a monoanionic NNN-pincer ligand is described. The 1,5-cyclooctadiene complexes, ArLIr(COD) (L = 2,5-(iPr2P=NAr)2C4H2N, Ar = Pipp, Dipp, Mes, COD = 1,5-cyclooctadiene) did not react with dihydrogen or silanes, precluding further work into catalytic processes, such as alkane dehydrogenation and hydrosilylation. As such, a more reactive species was sought. PippLIr(COE) (COE = cyclooctene) reacted with dihydrogen and silanes, allowing the synthesis of PippLIr(H)2 and PippLIr(H)(SiR3) (R3 = Et3, HPh2, H2Ph). These complexes were characterized by multinuclear (1H, 13C{1H}, 29Si, 31P{1H}) and 2-dimensional NMR spectroscopy, X-ray crystallography, and elemental analysis. Alternatives to PippLIr(COE), including PippLIr(CO), PippLIr(PPh3), and others were investigated. This was undertaken to avoid competing reactivity with free COE in solution. The efficacy of PippLIr(H)2 and PippLIr(H)(SiR3) (R3 = Et3, HPh2, H2Ph) as catalysts for alkene hydrogenation and alkane dehydrogenation, and hydrosilylation, respectively, was explored.

Authors

• Drescher, Sam L.
• University of Lethbridge. Faculty of Arts and Science

• iridium
• NNN-pincer ligand
• organometallic chemistry

Identifier

hdl:10133/6616

OAI identifier oai:identifier

oai:opus.uleth.ca:10133/6616