A New Homogeneous Catalyst for the Dehydrogenation of Dimethylamine Borane Starting with Ruthenium(III) Acetylacetonate

Barin, Ebru Unel
Masjedi, Mehdi
Özkar, Saim
The catalytic activity of ruthenium(III) acetylacetonate was investigated for the first time in the dehydrogenation of dimethylamine borane. During catalytic reaction, a new ruthenium(II) species is formed in situ from the reduction of ruthenium(III) and characterized using UV-Visible, Fourier transform infrared (FTIR), H-1 NMR, and mass spectroscopy. The most likely structure suggested for the ruthenium(II) species is mer-[Ru(N2Me4)(3)(acac)H]. Mercury poisoning experiment indicates that the catalytic dehydrogenation of dimethylamine-borane is homogeneous catalysis. The kinetics of the catalytic dehydrogenation of dimethylamine borane starting with Ru(acac)(3) were studied depending on the catalyst concentration, substrate concentration and temperature. The hydrogen generation was found to be first-order with respect to catalyst concentration and zero-order regarding the substrate concentration. Evaluation of the kinetic data provides the activation parameters for the dehydrogenation reaction: the activation energy E-a = 85 +/- 2 kJmol(-1), the enthalpy of activation H-# = 82 +/- 2 kJmol(-1) and the entropy of activation; S-# = -85 +/- 5 Jmol(-1)K(-1). The ruthenium(II) catalyst formed from the reduction of ruthenium(III) acetylacetonate provides 1700 turnovers over 100 hours in hydrogen generation from the dehydrogenation of dimethylamine borane before deactivation at 60 degrees C.


Highly active and long lived homogeneous catalyst for the dehydrogenation of dimethylamine borane starting with ruthenium(III) acetylacetonate and oleylamine precatalyst
DUMAN, SİBEL; Masjedi, Mehdi; Özkar, Saim (2016-01-01)
Herein, we report the results of our study on the homogeneous catalytic dehydrogenation of dimethylamine borane in the presence of Ru(acac)(3) and oleylamine (OAm) in toluene solution. The precatalyst system comprising Ru(acac)(3) and 3 equivalent OAm shows the high catalytic activity in hydrogen generation from dimethylamine borane solution. Monitoring the hydrogen evolution shows the presence of an induction period during which the homogeneous catalyst is formed, and then the hydrogen evolution continues ...
Hydroxyapatite-supported palladium(0) nanoclusters as effective and reusable catalyst for hydrogen generation from the hydrolysis of ammonia-borane
Rakap, Murat; Özkar, Saim (2011-06-01)
Herein we report the preparation, characterization and catalytic use of hydroxyapatite-supported palladium(0) nanoclusters in the hydrolysis of ammonia-borane. Palladium(0) nanoclusters were formed in situ from the reduction of palladium(II) ion exchanged hydroxyapatite during the hydrolysis of ammonia-borane and supported on hydroxyapatite. The hydroxyapatite-supported palladium(0) nanoclusters are stable enough to be isolated as solid materials and characterized by using a combination of advanced analytic...
Hydrodechlorination of trichloroethylene over Pd supported on swellable organically-modified silica (SOMS)
Sohn, Hyuntae; Çelik, Gökhan; Gunduz, Seval; Dean, Stacey L.; Painting, Eric; Edmiston, Paul L.; Ozkan, Umit S. (2017-04-01)
The catalytic activity and resistance to poisoning of Pd catalysts supported on swellable organically modified silica (SOMS) were investigated for hydrodechlorination (HDC) of trichloroethylene (TCE). The promising catalytic activity of 1% Pd/SOMS sample was attributed to the high affinity of SOMS for organics and its high hydrophobicity. While latter characteristic repels water, the adsorptive capacity for organics allows TCE dissolved in aqueous media to concentrate inside the pores, in the vicinity of th...
Addition of trifluoromethyltrimethylsilane to acyl phosphonates: Synthesis of TMS-Protected 1-alkyl-1-trifluoromethyl-1-hydroxyphosphonates and 1-aryldifluoroethenyl phosphates
Demir, Ayhan Sıtkı; Eymur, Serkan (American Chemical Society (ACS), 2007-10-26)
Addition reactions of nucleophilic CF3TMS to acyl phosphonates were investigated. Various acyl phosphonates reacted readily with CF3TMS in the presence of K2CO3 in DMF at rt to give 1-alkyl-2,2,2-trifluoro-1-trimethylsilyloxyethylphosphonate in 70−90% yields. When benzoyl phosphonates were used as starting material, after addition of CF3, the formed alcoholate undergoes phosphonate−phosphate rearrangement to form the acyl anion, followed by elimination of F- to give 1-aryldifluoroethenyl phosphates in 87−97...
Hydrogen generation from the hydrolysis of ammonia-borane using intrazeolite cobalt(0) nanoclusters catalyst
Rakap, Murat; Özkar, Saim (2010-04-01)
Previously being used as highly active catalyst in the hydrolysis of sodium borohydride, intrazeolite cobalt(0) nanoclusters were also employed as catalyst in the hydrolysis of ammonia-borane (H(3)NBH(3)). Intrazeolite cobalt(0) nanoclusters were found to be active catalyst in this hydrolysis reaction of ammonia-borane providing 5450 total turnovers at room temperature before deactivation. The results of the kinetic study shows that the catalytic hydrolysis of AB is first order with respect to the catalyst ...
Citation Formats
E. U. Barin, M. Masjedi, and S. Özkar, “A New Homogeneous Catalyst for the Dehydrogenation of Dimethylamine Borane Starting with Ruthenium(III) Acetylacetonate,” MATERIALS, pp. 3155–3167, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48662.