@article { ISI:000284052600021, title = {Covalently immobilized triphenylphosphine rhodium complex: synthesis, characterization, and application in catalytic olefin hydrogenation}, journal = {Chemcatchem}, volume = {2}, number = {11}, year = {2010}, month = {NOV}, pages = {1477-1482}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

A trimethoxysilane functionalized triphenylphosphine was coordinated to rhodium(I) and the resulting rhodium complex was covalently bound to a mesoporous SBA-15 support. The catalytic activity of this hybrid material was studied for the hydrogenation of 2-cyclohexen-1-one and compared with the corresponding homogeneous catalyst. According to the (31)P-MAS NMR data, the catalytically active species was stable against oxidation; no structural change could be detected after exposing it to air for more than two months. Transmission electron microscopy (TEM) measurements on the used catalyst confirmed that the rhodium species was also stable against reduction to the metal because the formation of rhodium nanoparticles during the catalysis could be excluded. The kinetic curves of the recycled system confirmed that this hybrid catalyst shows excellent activity, selectivity, stability, and reusability, and is truly heterogeneous in the hydrogenation reaction.

}, keywords = {alkenes, heterogeneous catalysis, Hydrogenation, mesoporous materials, Rhodium}, issn = {1867-3880}, doi = {10.1002/cctc.201000133}, author = {Wang, Lei and Jia, Mingjun and Shylesh, Sankaranarayanapillai and Philippi, Thomas and Seifert, Andreas and Ernst, Stefan and Singh, Anand Pal and Thiel, Werner R.} } @article { ISI:000306771600005, title = {Covalently anchored ruthenium-phosphine complex on mesoporous organosilica: catalytic applications in hydrogenation reactions}, journal = {Catalysis Communications}, volume = {25}, year = {2012}, month = {AUG}, pages = {22-27}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

New heterogeneous catalysts for alkene hydrogenation reactions were prepared by the immobilization of trimethoxysilane functionalized triphenylphosphine eta(6)-p-cymene ruthenium complex on mesoporous organosilica (PMO-Ru). Characterization techniques confirmed the structural integrity of the organosilica material and proved the successful anchoring of ruthenium complex. Catalytic activity and stability of PMO-Ru sample investigated in the hydrogenation of various olefins showed higher activity than a neat and MCM-41 supported ruthenium catalyst. High catalytic activity and stability of organosilica supported ruthenium catalyst are attributed to the hydrophobic environments and to the unique structural features imparted from the presence of organic groups in the framewall positions. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {Heterogenization, Hydrogenation, Organosilica, ruthenium, Triphenyl phosphine}, issn = {1566-7367}, doi = {10.1016/j.catcom.2012.04.002}, author = {Sisodiya, Sheetal and Lazar, Anish and Shylesh, Sankaranarayanapillai and Wang, Lei and Thiel, Werner R. and Singh, Anand Pal} } @article { ISI:000304106900015, title = {Electrostatic grafting of a triphenylphosphine sulfonate on SBA-15: application in palladium catalyzed hydrogenation}, journal = {Catalysis Science \& Technology}, volume = {2}, number = {6}, year = {2012}, month = {FEB}, pages = {1188-1195}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A novel strategy for the immobilization of a sulfonate functionalized triphenylphosphine ligand by ion-ion interactions on an imidazolium modified SBA-15 is presented. A support containing electrostatically grafted triphenylphosphine as the ligand was reacted with PdCl2( CNPh)(2) and the resulting hybrid material catalyzed olefin hydrogenation under mild conditions. The catalyst exhibits excellent activity, selectivity and stability and it can be reused for at least ten times without any loss of activity. An analogous but covalently grafted palladium system does not show any hydrogenation activity under the same conditions. TEM images of the used catalyst clearly prove the absence of palladium nanoparticles. Additionally, XPS investigations prove that palladium( 0) is formed and the phosphine is oxidized. By AAS no palladium contamination down to 0.5 X 10(-4) mmol could be detected in the products and further leaching tests verified the reaction to be truly heterogeneous. This concept of non-covalent immobilization guarantees a tight bonding of the catalytically active species to the surface in combination with a high mobility, which should be favorable for other catalyses, too.

}, issn = {2044-4753}, doi = {10.1039/c2cy00535b}, author = {Wang, Lei and Dehe, Daniel and Philippi, Thomas and Seifert, Andreas and Ernst, Stefan and Zhou, Zhou and Hartmann, Martin and Taylor, Robin N. Klupp and Singh, Anand Pal and Jia, Mingjun and Thiel, Werner R.} } @article { ISI:000315013200017, title = {Disordered mesoporous V/TiO2 system for ambient oxidation of sulfides to sulfoxides}, journal = {Applied Catalysis A-General}, volume = {452}, year = {2013}, month = {FEB}, pages = {132-138}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

High sulfide conversion and predominant sulfoxide yield has been observed with 0.1\% vanadium doped disordered mesoporous Ti1-xVxO2 material at ambient and sub ambient temperatures using environmentally green H2O2 oxidant. Ti1-xVxO2 materials were prepared by one-pot solution combustion method in less than 15 min and thoroughly characterized by X-ray diffraction, HRTEM, Raman spectra and other physicochemical techniques. Different sulfides, such as, phenylsulfide, methyl-p-tolylsulfide, ethylsulfide, thioanisole, were converted into the corresponding sulfoxide. Isolated V5+ incorporated in the TiO2 lattice is likely to be the active species for the sulfide oxidation reaction. Catalyst recycling studies indicates the robustness of the catalyst. (c) 2012 Elsevier B.V. All rights reserved.

}, keywords = {Ambient oxidation, Combustion synthesis, heterogeneous catalysis, Hydrogen peroxide, Mesoporous TiO2, Sulfoxidation, Sulfoxide}, issn = {0926-860X}, doi = {10.1016/j.apcata.2012.11.035}, author = {Negi, Sanjay Singh and Sivaranjani, Kumarsrinivasan and Singh, Anand Pal and Gopinath, Chinnakonda S.} } @article { ISI:000344998100063, title = {Green chemistry approach to styrene from ethylbenzene and air on MnxTi1-xO2 catalyst}, journal = {RSC Advances}, volume = {4}, number = {100}, year = {2014}, month = {OCT}, pages = {57087-57097}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Styrene (ST) is an industrially important commodity chemical, and design of a suitable catalyst, which provides high ethyl benzene (EB) conversion and styrene selectivity at Lower temperature with sustainable activity, is one of the major challenges in the field of heterogeneous catalysis. Manganese incorporated in titania (MnxT1-xO2) anatase Lattice, prepared via the solution combustion method, was evaluated for oxidative dehydrogenation (ODH) of EB with O-2 or air. MnxTi1-xO2 catalysts were characterized by different physiochemical methods. Up to 15\% Mn could be introduced into the TiO2 Lattice. TEM and XRD indicate disordered mesoporosity, further confirmed by adsorption isotherm analysis. MnxTi1-xO2 catalysts were evaluated for ST synthesis from EB using air or oxygen as oxidant between 440 and 570 degrees C. Reaction conditions have been varied systematically, such as catalyst composition, and EB/air/O-2 flow. MnxTi1-xO2 shows sustainable 55\% styrene yield for 45 h without deactivation under optimum conditions. A thorough analysis of spent catalysts demonstrates the conversion of initial anatase phase MnxTi1-xO2 to Mn3O4 supported on the rutile (R) phase of TiO2. The above change occurs in the first few hours of reaction and the Mn3O4 on R-TiO2 phase is the active phase of the catalyst and responsible for sustainable activity for Longer duration.

}, issn = {2046-2069}, doi = {10.1039/c4ra11814f}, author = {Negi, Sanjay Singh and Venugopalan, Aswathy Thareparambil and Raja, Thirumalaiswamy and Singh, Anand Pal and Gopinath, Chinnakonda S.} } @article { ISI:000372425600066, title = {Simple, phosphine free, reusable Pd(II)-2,2 {\textquoteleft}-dihydroxybenzophenone-SBA-15 catalyst for arylation and hydrogenation reactions of alkenes}, journal = {New Journal of Chemistry}, volume = {40}, number = {3}, year = {2016}, month = {JAN}, pages = {2423-2432}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An efficient, simple, phosphine and co-catalyst free C-C coupling reaction heterogeneous catalyst via a post grafting method is developed and reported. A covalently anchored phosphine free Pd(II) based 2,2{\textquoteright}-dihydroxybenzophenone (DHBP) complex over organofunctionalized SBA-15 has been synthesized by the reaction between aminofunctionalized SBA-15 (NH(2)SBA-15) and a 2,2{\textquoteright}-dihydroxybenzophenone (DHBP) ligand, and further complexation with Pd(II)Cl-2 to get Pd(II)-DHBP@ SBA-15. The synthesized catalysts were characterized by elemental analysis, XRD, N-2 sorption analyses, TG, DTA, FT-IR, solid state C-13 and Si-29 NMR spectra, XPS, UV-Visible, SEM, EDAX and TEM. The synthesized catalysts were screened in arylation (Heck reactions) and hydrogenation reactions of alkenes, and the results show that Pd(II)-DHBP@ SBA-15 exhibits high conversion and selectivity towards arylation and hydrogenation reactions of alkenes with high stability. The anchored solid catalysts can be recycled effectively and reused several times without major loss in activity.

}, issn = {1144-0546}, doi = {10.1039/c5nj02686e}, author = {Lazar, Anish and Vinod, Chathakudath P. and Singh, Anand Pal} }