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41.
New dicarboxylate-functionalized pillared materials with a general formula of λ-ZrPO4(OH)1-x(OOC(CH2)nCOO)x/2(dmso) (n=6, 8 and 10) have been prepared by post-synthesis modification of the inorganic layers of λ-zirconium phosphate (λ-ZrP), where the superficial Chloride monovalent anionic ligands of λ-layer are partially exchanged with the divalent anionic ligands of a series of long-chain aliphatic dicarboxylic acids, namely octanedioic acid, decanedioic acid and dodecanedioic acid. The synthesized materials are characterized by X-ray diffractometry, FT-IR spectrophotometry, elemental and thermogravimetric analyses. The X-ray diffraction patterns show that the obtained solid phases are pure. Furthermore, the interlayer distance of λ-ZrP systematically increases from 1.02 to 1.59 nm as a result of the incorporation of the mentioned acids inside the interlayer gallery. 相似文献
42.
Rajangam Vinodh Mani Ganesh Mei Mei Peng Aziz Abidov Muthiahpillai Palanichamy Wang Seog Cha Hyun-Tae Jang 《高分子科学》2015,33(2):224-235
Microporous hypercross-linked conjugated quinonoid chromophores represent a novel class of amorphous polymers, synthesized by the reaction of anthracene with dimethoxy methane in the presence of FeCl3 catalyst. Their N2 adsorption isotherms confirm their microporous nature. Diffuse reflectance UV-Visible(DRS UV-Vis) spectroscopy confirms their matrix built with the conjugated quinonoids by their broad light absorption characteristics extending from 1000 nm to 200 nm with the absorbance maximum close to 400 nm. The catalyst cross-linked anthracene with ―CH2― bridges and subsequently dehydrogenating them to form quinonoids. Their Fourier transform infrared(FTIR) spectra showed their characteristic quinonoid vibrations between 1600 and 1700 cm-1. The synthesis of polymers was carried out at 30, 40, 50, 60, 70 and 80 ℃, but the quinonoid content of the polymer obtained at 80 ℃ was higher than that of the others. Their scanning electron microscopy(SEM) images showed microspheres of 1 to 5 μm size built with tiny particles. Their surfaces were not smooth. The polymer synthesized at 80 ℃ showed 5.1 wt% CO2 sorption at 25 ℃ and 0.1 MPa, but when it was recross-linked, the CO2 sorption increased to 8 wt%. Hence, hypercross-linked conjugated quinonoid chromophores of anthracene are good for sorption of CO2. 相似文献
43.
Lorenzo Milli Dr. Nicola Zanna Andrea Merlettini Matteo Di Giosia Dr. Matteo Calvaresi Prof. Maria Letizia Focarete Prof. Claudia Tomasini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):12106-12112
We present herein the preparation of four different hydrogels based on the pseudopeptide gelator Fmoc‐l ‐Phe‐d ‐Oxd‐OH (Fmoc=fluorenylmethyloxycarbonyl), either by changing the gelator concentration or adding graphene oxide (GO) to the water solution. The hydrogels have been analysed by rheological studies that demonstrated that pure hydrogels are slightly stronger compared to GO‐loaded hydrogels. Then the hydrogels efficiency to trap the cationic methylene blue (MB) and anionic eosin Y (EY) dyes has been analyzed. MB is efficiently trapped by both the pure hydrogel and the GO‐loaded hydrogel through π–π interactions and electrostatic interactions. In contrast, the removal of the anionic EY is achieved in less satisfactory yields, due to the unfavourable electrostatic interactions between the dye, the gelator and GO. 相似文献
44.
Enhanced Catalytic Activity in Liquid‐Exfoliated FeOCl Nanosheets as a Fenton‐Like Catalyst 下载免费PDF全文
Jian Zhang Prof. Xiu‐Ling Jiao Dr. Yu‐Guo Xia Fang‐Fang Liu Ying‐Ping Pang Xin‐Fu Zhao Prof. Dai‐Rong Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9321-9329
A facile liquid‐phase exfoliation method to prepare few‐layer FeOCl nanosheets in acetonitrile by ultrasonication is reported. The detailed exfoliation mechanism and generated products were investigated by combining first‐principle calculations and experimental approaches. The similar cleavage energies of FeOCl (340 mJ m?2) and graphite (320 mJ m?2) confirm the experimental exfoliation feasibility. As a Fenton reagent, FeOCl nanosheets showed outstanding properties in the catalytic degradation of phenol in water at room temperature, under neutral pH conditions, and with sunlight irradiation. Apart from the increased surface area of the nanosheets, the surface state change of the nanosheets also plays a key role in improving the catalytic performance. The changes of charge density, density of states (DOS), and valence state of Fe atoms in the exfoliated FeOCl nanosheets versus plates illustrated that surface atomistic relationships made the few‐layer nanosheets higher activity, indicating the exfoliation process of the FeOCl nanosheets also brought about surface state changes. 相似文献
45.
Identification of radical structures on 1‐pentamethylbenzyl‐3‐ethylimidazoliumsilver(I)bromide and 1,3‐bis(pentamethylbenzyl)‐4,5‐dimethylbenzimidazoliumsilver(I)bromide exposed to gamma rays: an EPR study 下载免费PDF全文
Yusuf Ceylan Keziban Usta Ahmet Kunduracioglu Ayhan Usta Bekir Cetinkaya 《Magnetic resonance in chemistry : MRC》2016,54(11):864-869
1‐Pentamethylbenzyl‐3‐ethylimidazoliumsilver(I)bromide and 1,3‐bis(pentamethylbenzyl)‐4,5dimethylbenzimidazoliumsilver(I)bromide and their Ag+ complexes were synthesized and their polycrystal forms were produced by recrystallization in dichloromethane/Et2O solvent system. Structural determinations were carried out by 1H NMR and 13C NMR with a Varian 400 NMR system using tetramethylsilane as internal standard and CDCl3 as solvent. The disappearance of acidic N‐heterocyclic carbene proton showed the formation of Ag(I) complexes. Also, elemental analyses were carried out. Electron paramagnetic resonance (EPR) measurements were performed to determine the formed radical structure on the samples irradiated at the room temperature for 72 h by using 60Co‐source with dose rate of 0.680 kGy. The EPR measurements were carried out in the temperature range of 200 K–450 K. Identical radicals were determined on the irradiated compounds. It was observed that the shapes of the spectra of the samples were independent of the temperature but, the resonance line intensities changed linearly with the temperature. Also, it was detected that the free radical on the 1‐pentamethylbenzyl‐3‐ethylimidazoliumsilver(I)bromide is not stable compared to that on the 1,3‐bis(pentamethylbenzyl)‐4,5dimethylbenzimidazoliumsilver(I)bromide. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
46.
分析和总结了催化剂催化有机化学反应的4种基本方式,包括建立电子流动通道、改变电子流动属性、加强电子流动能力和稳定电子流动结果。本文旨在揭示有机化学反应中催化剂作用的本质,以便学生更加深刻理解并掌握有机化学反应。 相似文献
47.
In‐Depth Understanding of the Chemical Properties of Rarely Explored Carbide Cluster Metallofullerenes: A Case Study of Sc2C2@C3v(8)‐C82 that Reveals a General Rule 下载免费PDF全文
Wenting Cai Muqing Chen Lipiao Bao Dr. Yunpeng Xie Prof. Dr. Takeshi Akasaka Prof. Dr. Xing Lu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3449-3454
The chemical properties of carbide‐cluster metallofullerenes (CCMFs) remain largely unexplored, although several new members of CCMFs have been discovered recently. Herein, we report the reaction between Sc2C2@C3v(8)‐C82, which is viewed as a prototypical CCMF because of its high abundance, and 3‐triphenylmethyl‐5‐oxazolidinone ( 1 ) to afford the corresponding pyrrolidino derivative Sc2C2@C3v(8)‐C82(CH2)2NTrt ( 2 ; Trt=triphenylmethyl). Single‐crystal X‐ray crystallography studies of 2 revealed that the reaction takes place at a [6,6]‐bond junction, which is directly over the encapsulated C2 unit and is far from either of the two scandium atoms. On the basis of theoretical calculations and by considering previously reports, we have found that a hexagonal carbon ring on the cage of Sc2C2@C3v(8)‐C82 is highly reactive toward different reagents due to the overlap of high p‐orbital axis vector (POAV) angles and large LUMO coefficients. We propose that this highly concentrated area of reactivity is generated by the encapsulation of the Sc2C2 cluster because this region is absent from the empty fullerene C3v(8)‐C82. Moreover, the absorption and electrochemical results confirm that derivative 2 is more stable than pristine Sc2C2@C3v(8)‐C82, thus illuminating its potential applications. 相似文献
48.
Prediction of 195Pt NMR chemical shifts of dissolution products of H2[Pt(OH)6] in nitric acid solutions by DFT methods: how important are the counter‐ion effects? 下载免费PDF全文
Athanassios C. Tsipis Ioannis N. Karapetsas 《Magnetic resonance in chemistry : MRC》2016,54(8):656-664
195Pt NMR chemical shifts of octahedral Pt(IV) complexes with general formula [Pt(NO3)n(OH)6 ? n]2?, [Pt(NO3)n(OH2)6 ? n]4 ? n (n = 1–6), and [Pt(NO3)6 ? n ? m(OH)m(OH2)n]?2 + n ? m formed by dissolution of platinic acid, H2[Pt(OH)6], in aqueous nitric acid solutions are calculated employing density functional theory methods. Particularly, the gauge‐including atomic orbitals (GIAO)‐PBE0/segmented all‐electron relativistically contracted–zeroth‐order regular approximation (SARC–ZORA)(Pt) ∪ 6–31G(d,p)(E)/Polarizable Continuum Model computational protocol performs the best. Excellent second‐order polynomial plots of δcalcd(195Pt) versus δexptl(195Pt) chemical shifts and δcalcd(195Pt) versus the natural atomic charge QPt are obtained. Despite of neglecting relativistic and spin orbit effects the good agreement of the calculated δ 195Pt chemical shifts with experimental values is probably because of the fact that the contribution of relativistic and spin orbit effects to computed σiso 195Pt magnetic shielding of Pt(IV) coordination compounds is effectively cancelled in the computed δ 195Pt chemical shifts, because the relativistic corrections are expected to be similar in the complexes and the proper reference standard used. To probe the counter‐ion effects on the 195Pt NMR chemical shifts of the anionic [Pt(NO3)n(OH)6 ? n]2? and cationic [Pt(NO3)n(OH2)6 ? n]4 ? n (n = 0–3) complexes we calculated the 195Pt NMR chemical shifts of the neutral (PyH)2[Pt(NO3)n(OH)6 ? n] (n = 1–6; PyH = pyridinium cation, C5H5NH+) and [Pt(NO3)n(H2O)6 ? n](NO3)4 ? n (n = 0–3) complexes. Counter‐anion effects are very important for the accurate prediction of the 195Pt NMR chemical shifts of the cationic [Pt(NO3)n(OH2)6 ? n]4 ? n complexes, while counter‐cation effects are less important for the anionic [Pt(NO3)n(OH)6 ? n]2? complexes. The simple computational protocol is easily implemented even by synthetic chemists in platinum coordination chemistry that dispose limited software availability, or locally existing routines and knowhow. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
49.
Molecular Size and Electronic Structure Combined Effects on the Electrogenerated Chemiluminescence of Sulfurated Pyrene‐Cored Dendrimers 下载免费PDF全文
Dr. Giovanni Valenti Dr. Andrea Fiorani Dr. Simone Di Motta Dr. Giacomo Bergamini Prof. Marc Gingras Prof. Paola Ceroni Prof. Fabrizia Negri Prof. Francesco Paolucci Prof. Massimo Marcaccio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2936-2947
The electrochemistry, photophysics, and electrochemically generated chemiluminescence (ECL) of a family of polysulfurated dendrimers with a pyrene core have been thoroughly investigated and complemented by theoretical calculations. The redox and luminescence properties of dendrimers are dependent on the generation number. From low to higher generation it is both easier to reduce and oxidize them and the emission efficiency increases along the family, with respect to the polysulfurated pyrene core. The analysis of such data evidences that the formation of the singlet excited state by cation–anion annihilation is an energy‐deficient process and, thus, the ECL has been justified through the triplet–triplet annihilation pathway. The study of the dynamics of the ECL emission was achieved both experimentally and theoretically by molecular mechanics and quantum chemical calculations. It has allowed rationalization of a possible mechanism and the experimental dependence of the transient ECL on the dendrimer generation. The theoretically calculated Marcus electron‐transfer rate constant compares very well with that obtained by the finite element simulation of the whole ECL mechanism. This highlights the role played by the thioether dendrons in modulating the redox and photophysical properties, responsible for the occurrence and dynamics of the electron transfer involved in the ECL. Thus, the combination of experimental and computational results allows understanding of the dendrimer size dependence of the ECL transient signal as a result of factors affecting the annihilation electron transfer. 相似文献
50.
Normal halogen dependence of 13C NMR chemical shifts of halogenomethanes revisited at the four‐component relativistic level 下载免费PDF全文
Dmitry O. Samultsev Yury Yu. Rusakov Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2016,54(10):787-792
The ‘Normal Halogen Dependence’ of 13C NMR chemical shifts in the series of halogenomethanes is revisited at the four‐component relativistic level. Calculations of 13C NMR chemical shifts of 70 halogenomethanes have been carried out at the density functional theory (DFT) and MP2 levels with taking into account relativistic effects using the four‐component relativistic theory of Dirac‐Coulomb within the different computational methods (4RPA, 4OPW91) and hybrid computational schemes (MP2 + 4RPA, MP2 + 4OPW91). The most efficient computational protocols are derived for practical purposes. Relativistic shielding effect reaches as much as several hundreds of ppm for heavy halogenomethanes, and to account for this effect in comparison with experiment at the qualitative level, relativistic Dyall's basis sets of triple‐zeta quality or higher are to be used within the framework of the four‐component relativistic theory taking into account solvent effects. Relativistic geometrical optimization (as compared with the non‐relativistic level) is essential for the molecules containing at least two iodines at one carbon atom. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献