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Dr. Donald Linn
Department of Chemistry
Indiana University – Purdue University Fort Wayne
Research on the hydrogenation of olefins and arenes using catalysis is dominant in Europe, because of the limited availability of petroleum. Finding an efficient, inexpensive and available hydrogen-storage catalyst would permit alternative methods for catalysis and energy storing processes. Most hydrogenation research conducted currently uses precious metal catalysts. Here this research focuses on a more earth-abundant metal, cobalt. The novel binuclear cobalt hydride complex, [Co2H9][MgBr(THF)]5, was used to catalyze the hydrogenation of a series of substrates at room temperature.* The substances chosen comprise an arene, a diene and a sterically hindered olefin: naphthalene, trans, trans-1,4-diphenyl-1,3-butadiene, and 1-methylcyclohexene. The reactions were analyzed using hydrogen uptake, gas chromatography with flame ionization detection (GC-FID), hydrogen nuclear magnetic resonance (1H NMR) and carbon nuclear magnetic resonance (13C NMR). All reactions showed 100% conversion and gave up to 200 catalytic turnovers (TO = mol product/mol cobalt dimer) to take anywhere from 1 to 50 hours. The reactions with naphthalene entail a long induction period, that signals an autocatalytic pathway.** The naphthalene conversion to tetralin was observed to show a 20 hour induction period. There was no induction period for the rapid hydrogenation of trans, trans-1,4-diphenyl-1,3-butadiene to 1,4-diphenylbutane. Further, the substrate 1-methylcyclohexene also showed complete conversion within hours. ________________
*Linn, Donald, Kieser, Jerod, Shearer, Jason. The novel hydrogen-rich binuclear cobalt complex anion, [(CoH3)2H3]5-. Dalton Trans. 2014, 43, 3412-3415.
** Finney, E. E.; Finke, R. G. Nanocluster nucleation and growth kinetic and mechanistic studies: A review emphasizing transition-metal nanoclusters. J. of Colloid and Interface Sci. 2008, 317 (2), 351-374.
Chemistry | Physical Sciences and Mathematics
Griffith, Cameron A., "Room Temperature Catalytic Hydrogenation of Olefins and Arenes Using [Co2H9][MgBr(THF)]5" (2014). 2014 IPFW Student Research and Creative Endeavor Symposium. 48.