Topic
MCM-41
About: MCM-41 is a research topic. Over the lifetime, 2355 publications have been published within this topic receiving 91416 citations.
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TL;DR: In this article, a luminescent platinum(II) complex platinum 5,10,15,20-tetra{4-[(N-carbazyl)butyloxyphenyl]}porphyrin (PtTCBPyP) has been synthesized and characterized by H-1 NMR, elemental analysis, IR and UV-vis.
Abstract: A novel luminescent platinum(II) complex platinum 5,10,15,20-tetra{4-[(N-carbazyl)butyloxyphenyl]}porphyrin (PtTCBPyP) has been synthesized and characterized by H-1 NMR, elemental analysis, IR and UV-vis. The platinum porphyrin is assembled with mesoporous silica SBA-15 and MCM-41 resulting in the assembly materials PtTCBPyP/SBA-15 and PtTCBPyP/MCM-41. The luminescence of platinum porphyrin complex/silicate assemble materials can be quenched by molecular oxygen with very high response (I-0/I-100 > 8700 for PtTCBPyP/SBA-15(20 mg/g) and I-0/I-100 > 3800 for PtTCBPyP/MCM-41(20 mg/g)), indicating that platinum porphyrin complex/silicate systems can be employed to develop high performance oxygen sensors. Among this assembly system, PtTCBPyP/SBA-15(20 mg/g) exhibits the highest response of platinum porphyrin complex/silica. (C) 2013 Elsevier B.V. All rights reserved.
41 citations
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TL;DR: A combination of mesoporous structure with acidic properties makes the MCM-41 functionalized with phosphate groups promising for use as solid acid catalysts.
Abstract: Mesoporous molecular sieves Si-MCM-41 (purely siliceous) and Ti-MCM-41 (partly covered with a surface layer of TiO2) were functionalized with phosphate groups by treatment with POCl3 (denoted -MCM-41(P) and Ti-MCM-41(P), respectively). With the use of TEM, X-ray diffraction, and N2 adsorption, it was shown that the initial hexagonal structure, the high specific surface area, and porosity are retained in the functionalized materials but are not as good as in the starting materials. 1H MAS NMR and 31P MAS NMR revealed that the surface of Si-MCM-41(P) consists of silicon phosphate and pyrophosphate species. That of Ti-MCM-41(P) additionally contains titanium dihydro-, hydro-, and pyrophosphate species, the latter being predominant. TPD of adsorbed ammonia for Si-MCM-41(P) and Ti-MCM-41(P) showed that functionalization leads to the creation of moderate and strong acid sites. A combination of mesoporous structure with acidic properties makes the MCM-41 functionalized with phosphate groups promising for use as ...
41 citations
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TL;DR: In this article , mesoporous silica nanoparticles (MSNs) composed of MCM-41 were synthesized and modified with amine groups (i.e., NH2) to form NH2/MCM- 41, which was loaded with curcumin (CUR) to create an efficient carriers in drug delivery systems (DDSs).
40 citations
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TL;DR: In this paper, a new heterogeneous catalysts for alkene metathesis were prepared by immobilization of molybdenum dioxide bis(acetylacetonate), bis(glycolate), and bis( glycolate) on mesoporous molecular sieve SBA-15.
Abstract: New heterogeneous catalysts for alkene metathesis were prepared by immobilization of molybdenum dioxide bis(acetylacetonate) and molybdenum dioxide bis(glycolate) on mesoporous molecular sieve SBA-15. Thermal spreading (TS) method and wet impregnation (WI) followed by calcinations were employed as synthesis approaches. These new catalysts represent inexpensive, easy-to-prepare and highly active and selective heterogeneous catalysts for metathesis of higher linear 1-alkenes applicable under mild reaction conditions without the necessity of solvent or co-catalyst in the reaction mixture. In metathesis of 1-octene, these catalysts showed up to four times higher activity compared with MoO 3 supported on conventional silica as well as on SBA-15. This is probably due to the better dispersion of the molybdenum oxide phase on the mesoporous support surface. In metathesis of 1-dodecene and 1-tetradecene these catalysts based on SBA-15 exhibited a significantly higher activity than corresponding catalysts on MCM-41, probably due to the larger pores.
40 citations
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TL;DR: In this paper, Tungstophosphoric acid (TPA) over zirconia dispersed uniformly in mesoporous silica (MS) channels of MCM41 and MCM-48 were synthesized and tested for their catalytic activity in veratrole acetylation.
Abstract: Tungstophosphoric acid (TPA) over zirconia dispersed uniformly in mesoporous silica (MS) channels of MCM-41 and MCM-48 were synthesized and tested for their catalytic activity in veratrole acetylation. Catalysts with different TPA loadings (5–50 wt.%) on 22.4 wt.%ZrO2/MCM-41 and 15 wt.%TPA on different zirconia loadings (10–70 wt.%)/MCM-41 were prepared and calcined at 1123 K. The physico-chemical characterization of the supported catalysts was done by powder X-ray diffraction (XRD), surface area measurement (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed-infrared (FT-IR) spectroscopy, UV–vis diffuse reflectance spectra, Temperature programmed desorption (TPD) of ammonia, FT-IR pyridine adsorption and 31P cross polarization-magic angle spinning (CP-MAS) NMR spectroscopy. The mesoporous silica supports play an important role in stabilizing catalytically active TPA along with tetragonal phase of zirconia. Among the catalysts, 15 wt.%TPA/22.4 wt.%ZrO2/MCM-41 calcined at 1123 K was found to have highest acidity and at least four times more active than neat 15 wt.%TPA/ZrO2 in veratrole acetylation to acetoveratrone by acetic anhydride. Reaction conditions were evaluated with 15 wt.%TPA/22.4 wt.%ZrO2/MCM-41 calcined at 1123 K to get higher conversion of acetic anhydride to acetoveratrone. The reaction was found to be heterogeneously catalyzed and no contribution from homogeneous (leached) TPA into the medium under the reaction conditions.
40 citations