- Novel mesoporous materials with a uniform distribution of organic groups and inorganic oxide in their frameworks
-
Novel organic-inorganic hybrid mesoporous materials have been synthesized, in which organic and inorganic oxide moieties are distributed homogeneously at the molecular level in the framework, forming a covalently bonded network. They are highly ordered at the mesoscale, with two-and three-dimensional hexagonal symmetries and well-defined external morphologies. Nitrogen adsorption measurements show a uniform pore-size distribution with pore diameters of 31 and 27 A, and high surface areas of 750 and 1170 m2/g. The synthetic procedure to polymerize the organosilane monomer containing two trialkoxysilyl groups in the presence of surfactant can be applied to the synthesis of a variety of highly ordered organic-inorganic hybrid mesoporous materials.
- Inagaki, Shinji,Guan, Shiyou,Fukushima, Yoshiaki,Ohsuna, Tetsu,Terasaki, Osamu
-
-
Read Online
- High Production of Hydrogen on Demand from Silanes Catalyzed by Iridium Complexes as a Versatile Hydrogen Storage System
-
The catalytic dehydrogenative coupling of silanes and alcohols represents a convenient process to produce hydrogen on demand. The catalyst, an iridium complex of the formula [IrCp?(Cl)2(NHC)] containing an N-heterocyclic carbene (NHC) ligand functionalized with a pyrene tag, catalyzes efficiently the reaction at room temperature producing H2 quantitatively within a few minutes. As a result, the dehydrogenative coupling of 1,4-disilabutane and methanol enables an effective hydrogen storage capacity of 4.3 wt % that is as high as the hydrogen contained in the dehydrogenation of formic acid, positioning the silane/alcohol pair as a potential liquid organic hydrogen carrier for energy storage. In addition, the heterogenization of the iridium complex on graphene presents a recyclable catalyst that retains its activity for at least 10 additional runs. The homogeneous distribution of catalytic active sites on the basal plane of graphene prevents diffusion problems, and the reaction kinetics are maintained after immobilization.
- Ventura-Espinosa, David,Sabater, Sara,Carretero-Cerdán, Alba,Baya, Miguel,Mata, Jose A.
-
p. 2558 - 2566
(2018/03/13)
-
- Phosphiranes as ligands for platinum catalysed hydrosilylations
-
The stability of phosphiranes can be enhanced by inclusion of the PC2 ring into a polycyclic framework. BABAR-Phos type phosphiranes are easily prepared in high yield, they are thermally stable and allow the synthesis of various platinum(0) complexes. In contrast to other platinum(0) phosphine complexes, these are active hydrosilylation catalyst precursors. The reversible insertion of an electron rich metal centre into one P-C bond of the phosphirane ring was demonstrated for the first time.
- Liedtke, Jürgen,Loss, Sandra,Widauer, Christoph,Grützmacher, Hansj?rg
-
p. 143 - 156
(2007/10/03)
-
- RHODIUM(I)-MONO- UND -DIAZADIENEKOMPLEXE, SYNTHESE, SPEKTROSKOPISCHE CHARAKTERISIERUNG, OXIDATIVE ADDITIONSREAKTIONEN UND EINSATZ IN DER HOMOGENEN KATALYSE ZUR HYDROSILYLIERUNG
-
The reaction of(Rh(CO)2Cl)2 with di- and monoazadienes gives planar, four-coordinated rhodium(I) complexes Rh(CO)Cl(DAD) (III) and Rh(CO)Cl(MAD)2 (V), respectively, which catalyse the hydrosilylation of alkenes and alkynes.In a stereoselektive cis-addition symmetric internal alkynes give the corresponding silyl alkenes, while the catalytic addition of silane to terminal alkynes leads to the 2-silyl and cis-and trans-1-silyl-alkenes; their ratio depends on the controlling ligand and on the reaction conditions.With a stoichiometric amount of the silane the complexes III react under oxidative addition to give the rhodium(III) complexes Rh(H)(SiR3)(DAD)Cl (VI), which also catalyse the hydrosilylation.
- Brockmann, Monika,Dieck, Heindirk tom,Klaus, Juergen
-
p. 209 - 226
(2007/10/02)
-
- CATALYSIS OF HYDROSILYLATION. PART II. ADDITION OF TRIALKOXYSILANES TO VINYLTRIALKOXYSILANES CATALYZED BY TRANSITION METAL COMPLEXES
-
Hydrosilylation of vinyltrialkoxysilanes by trialkoxysilanes catalyzed by various transition metal complexes: H2PtCl6, (PPh3)3RhCl, (PPh3)3RuCl2, Ru(acac)3, Ni(acac)2 was found to proceed giving mostly 1,2-bis(trialkoxysilyl)ethane (β-adduct) as the main product.In presence of ruthenium complexes, besides β-adduct, unsaturated product of dehydrogenative double hydrosilylation (RO)3SiCH=CHSi(OR)3 (where R=C2H5, iso-C3H7) was obtained as a by-product, except for trimethoxysilyl derivatives, where α-adduct was found.Addition of trialkoxysilane to vinyltrialkoxysilanecontaining different substituents at two silicon atoms proceeds via RO/R'O exchange of the successive substituents, followed by hydrosilylation of all vinylsilanes by all trisubstituted silanes.
- Marciniec, Bogdan,Gulinski, Jacek,Urbaniak, Wlodzimierz
-
p. 287 - 296
(2007/10/02)
-