Hydrogen Generation from Water upon CpMn(CO)₃ Irradiation in a Hexane/Water Biphasic System

Abstract

Photolysis of CpMn(CO)3 in a hexane/water biphasic system has been shown to generate hydrogen peroxide and hydrogen in 40−50% yield. Photolysis of the title compound results in loss of a CO ligand followed by coordination of a water molecule. The initially formed CpMn(CO)2(H2O) intermediate was detected using time-resolved IR spectroscopy. The cyclopentadiene (CpH) monomer is generated as the major product, formed by the transfer of an H atom from the coordinated H2O solvent to the Cp ring. A simple mechanism for H2 generation is proposed on the basis of deuteration studies which demonstrate the production of D2 and CpD upon photolysis of CpMn(CO)3 in a hexane/D2O biphasic system.

Hydrogenation of a Rhodium Peroxido Complex by Formate Derivatives: Mechanistic Studies and the Catalytic Formation of H2O2 from O2

“…[24] The molecule exhibits a distorted octahedral geometry with the two phosphines in a mutually trans orientation. [27] In conclusion, we have demonstrated a variety of hydrogenation reactions of the peroxido ligand in trans-[Rh(O 2 )(4-C 5 F 4 N)(CNtBu)(PEt 3 ) 2 ] (1 a), which can be prepared from dioxygen and 2, to yield H 2 O 2 and the rhodium(I) compound 2. The O-O distances in other cyclic peroxycarbonatocomplexes are also in a similar range, as found for 7 a.…”

“…Based on 1 a, 3.6 equiv of H 2 O 2 were formed. [27] In conclusion, we have demonstrated a variety of hydrogenation reactions of the peroxido ligand in trans-[Rh(O 2 )(4-C 5 F 4 N)(CNtBu)(PEt 3 ) 2 ] (1 a), which can be prepared from dioxygen and 2, to yield H 2 O 2 and the rhodium(I) compound 2. To the best of our knowledge, the hydrogenation of dioxygen with formic acid or ammonium formate in the homogeneous phase mediated by a transition metal complex is unprecedented.…”

N,N′-Bis[3,5-bis(2,6-diisopropylphenyl)phenyl]butane-2,3-diimine

“…For background to water splitting, see: Yang & Hall (2010); Kee et al (2011); Blakemore et al (2010). For related structures, see: Ionkin & Marshall (2004); Zou et al (2008); Lohr et al (2011).…”

“…To do their part, chemists have been looking at the steps towards organometallic mono-nuclear water splitting. (Yang & Hall, 2010;Kee et al, 2011;Blakemore et al, 2010). Our group is currently exploring the usage of platinum to mediate this reaction in an effort to understand the fundamental steps of O-H and O-O bond activation.…”

1,2-Bis{[3,5-bis(2,6-diisopropylphenyl)phenyl]imino}acenaphthene toluene monosolvate

“…For background to water splitting, see: Yang & Hall (2010); Kee et al (2011); Blakemore et al (2010). For related structures, see: El-Ayaan et al (2003, 2004; Fedushkin et al (2004); Coventry et al (2004); Lohr et al (2011).…”