Highly porous N-doped activated carbon monoliths (ACMs) are fabricated by carbonization and physical activation of mesoporous polyacrylonitrile (PAN) monoliths in the presence of CO(2). The monoliths exhibit exceptionally high CO(2) uptake; 5.14 mmol g(-1) at ambient pressure and temperature and 11.51 mmol g(-1) at ambient pressure and 273 K.
Iron containing porous organic polymers (Fe-POPs) have been synthesized by a facile one-pot bottom-up approach to porphyrin chemistry by an extended aromatic substitution reaction between pyrrole and aromatic dialdehydes in the presence of small amount of Fe(III). The Fe-POPs possess very high BET surface area, large micropores and showed excellent CO(2) capture (~19 wt%) at 273 K/1 bar.
A highly ordered 2D‐hexagonal mesoporous silica material is functionalized with 3‐aminopropyltriethoxysilane. This organically modified mesoporous material is grafted with a dialdehyde fluorescent chromophore, 4‐methyl‐2,6‐diformyl phenol. Powder X‐ray diffraction, transmission electron microscopy, N2 sorption, Fourier transform infrared spectroscopy, and UV‐visible absorption and emission have been employed to characterize the material. This material shows excellent selective Zn2+ sensing, which is due to the fluorophore moiety present at its surface. Fluorescence measurements reveal that the emission intensity of the Zn2+‐bound mesoporous material increases significantly upon addition of various concentrations of Zn2+, while the introduction of other biologically relevant (Ca2+, Mg2+, Na+, and K+) and environmentally hazardous transition‐metal ions results in either unchanged or weakened intensity. The enhancement of fluorescence is attributed to the strong covalent binding of Zn2+, evident from the large binding constant value (0.87 × 104 M−1). Thus, this functionalized mesoporous material grafted with the fluorescent chromophore could monitor or recognize Zn2+ from a mixture of ions that contains Zn2+ even in trace amounts and can be considered as a selective fluorescent probe. We have examined the application of this mesoporous zinc(II) sensor to cultured living cells (A375 human melanoma and human cervical cancer cell, HeLa) by fluorescence microscopy.
Heterodimerization of olefins is a reaction of enormous synthetic potential, since it has been demonstrated that excellent yields and selectivities can be achieved under exceptionally mild conditions in many cases. 1,2 For example, we have recently shown that using catalysts derived from [(allyl)Ni(Br)] 2 and a tertiary phosphine in combination with a silver salt, a nearly quantitative hydrovinylation of vinylarenes can be achieved (eq 1). In our initial efforts to find a broadly applicable asymmetric version of this reaction, 2 we considered the requirement of a coordination site for ethylene on the putative cationic Ni intermediates, and chose (R)-2-diphenylphosphino-2′-alkoxy-1,1′-binaphthyl (MOP), 3 in which the 2′-methoxy group would play the role of a 'hemilabile′ ligand 4 (eq 2). With the fortuitous choice of this ligand, we also realized that counterions played a key role in the success of this reaction. For example, we found that AgOTf, which gave in many cases isolated yields >95% with Ph 3 P as a ligand, gave low yields in the hydrovinylation reactions using the MOP ligands. In sharp contrast, the use of Na + B[(3,5-(CF 3 ) 2 C 6 H 3 )] 4 -(NaBARF) in conjunction with MOP fully restored the activity of the catalyst (eq 2). 5 Since this original discovery, we have sought to clarify the role of hemilabile chelation and of the effect of various counterions on the efficiency and selectivity of the Ni-and Pd-catalysts for this reaction. With this goal, variation of the 2′ substituent of the MOP ligand was studied. In addition, we synthesized a new class of "tunable" hemilabile 1-aryl-2,5-dialkylphospholanes which were found to be exceptionally good ligands for the exacting hydrovinylation reaction, if and only if the appropriate counterions are used. The results of these studies are reported in this paper.
Mesoporous polyacrylonitrile (PAN) monolith has been fabricated by a template-free approach using the unique affinity of PAN towards a water/dimethyl sulfoxide (DMSO) mixture. A newly developed Thermally Induced Phase Separation Technique (TIPS) has been used to obtain the polymer monoliths and their microstructures have been controlled by optimizing the concentration and cooling temperature.
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