Pyridine-Based Catalytically Active PNNH-Ru Pincer Complexes with Potential Dual Modes of Metal Ligand Cooperation

JAI ANAND GARG, Organic chemistry, Weizmann Institute of Science, Rehovot, Israel

Organometallic complexes that show metal ligand cooperation (MLC) with incoming substrates play an important role in catalysis [1-3]. A novel class of phosphino-pyridyl ruthenium pincer complexes having sec-amine coordination is presented here. A potential MLC can be expected by both amine-amide and aromatization-dearomatization ligand transformations. These complexes were found to be effective pre-catalysts for acceptorless dehydrogenative coupling of alcohols to esters and hydrogenation of esters at unprecedented mild conditions [4]. 

A structurally characterized monoanionic enamido Ru(II) complex which was obtained by treating the sec-amine complex with base is thought to be the active catalyst.   

REFERENCES

[1]   Ikariya T. and Shibasaki M.,“Bifunctional Molecular Catalysis”, 1st edition, vol. 37, Springer, Berlin, Heidelberg, (2011).

[2]   Gunanathan C and Milstein D., “Applications of Acceptorless Dehydrogenation and Related Transformations in Chemical Synthesis” Science 2013, 341.

[3]   Gunanathan C and Milstein D., “Metal-ligand cooperation by aromatization-dearomatization: a new paradigm in bond activation and "green" catalysis” Acc. Chem. Res. 2011, 44, 588.

[4]   Fogler E., Garg, J. A., Hu P., Leitus G., Shimon L. J. W and Milstein D., “System with Potential Dual Modes of Metal Ligand Cooperation: Highly Catalytically Active Pyridine-Based PNNH-Ru Pincer Complexes” Chem Eur. J. 2014, 20, 15727.