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Ao‐kai Zhang Jun Ling Kewen Li Guo‐dong Fu Tasuku Nakajima Takayuki Nonoyama Takayuki Kurokawa Jian Ping Gong 《Journal of Polymer Science.Polymer Physics》2016,54(13):1227-1236
In this study, controlled amount of dangling ends is introduced to the two series of poly(ethylene glycol)‐based hydrogel networks with three and four crosslinking functionality by using click chemistry. The structure of the gels with regulated defect percentage is confirmed by comparing the results of low‐field NMR characterization and Monte Carlo simulation. The mechanical properties of these gels were characterized by tensile stress–strain behaviors of the gels, and the results are analyzed by Gent model and Mooney–Rivlin model. The shear modulus of the swollen gels is found to be dependent on the functionality of the network, and decreases with the defect percentage. Furthermore, the value of shear modulus well obeys the Phantom model for all the gels with varied percentage of the defects. The maximum extension ratio, obtained from the fitting of Gent model, is also found to be dependent on the functionality of the network, and does not change with the defect percentage, except at very high defect percentage. The value of the maximum extension ratio is between that predicted from Phantom model and the Affine model. This indicates that at the large deformation, the fluctuation of the crosslinking points is suppressed for some extend but still exists. Polymer volume fractions at various defect percentages obtained from prediction of Flory–Rehner model are found to be in well agreement with the swelling experiment. All these results indicate that click chemistry is a powerful method to regulate the network structure and mechanical properties of the gels. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1227–1236 相似文献
3.
Prof. Dr. Tomoaki Tanase Dr. Kanako Nakamae Yume Okawa Mami Hamada Dr. Arimasa Matsumoto Prof. Dr. Takayuki Nakajima Prof. Dr. Takuya Nakashima Prof. Dr. Tsuyoshi Kawai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104060
A P-stereogenic linear tetraphosphine tetraoxide, (R,R)- or (S,S)-dpmppm(=O)4, was synthesized to prepare C2 dinuclear M(hfa)3 complexes (M=Eu, Tb, Y) as the first example of lanthanide(III) complexes with P-chiral multidentate phosphine oxides. The mononuclear M(hfa)3 complexes (M=Eu, Y) with a P-chiral diphosphine dioxide, tpdpb(=O)2, were also prepared, and comparison of their photophysical properties for the EuIII complexes revealed that significant chiral induction from the P-chiral centers arises on the achiral M(hfa)3 units through intramolecular π-π stacking constraint in the dinuclear system. 相似文献
4.
Dr. Tetsuo Tsuchiya Dr. Tomohiko Nakajima Yuko Uzawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(42):9261-9276
This review summarizes the use of photoreactions that replace conventional heating processes for growing oxide thin films from chemical solutions. In particular, this review outlines key variables in photoreactions that affect epitaxial and polycrystalline thin film growth, including precursor materials, laser wavelength, laser fluence, and carbon. In addition, the features of the photoreaction process that can be controlled at a low temperature by oxygen non-stoichiometry are examined. Likewise, functions that are neither achieved by developing a gradient structure nor controlled by a thermal equilibrium reaction are detailed. Two new concepts are presented, known as photoreaction of nanoparticles (PRNP) and photoreaction of a hybrid solutions (PRHS), in which crystal nuclei are pre-dispersed in a metal–organic compound film. This method has successfully produced flexible phosphor films used as resistor or thermistor electronic components. Finally, thin film growth using different light sources such as flash lamps and femtosecond lasers (fs) is explored. 相似文献
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Stadnyk V. Yo. Shchepanskyi P. A. Rudysh M. Ya. Kogut Z. A. 《Journal of Applied Spectroscopy》2021,88(4):831-837
Journal of Applied Spectroscopy - The temperature dependence of the refractive indices of K2SO4 with copper impurity was investigated. It was found that introduction of the copper impurity leads to... 相似文献
7.
Prof. Takayuki Nakajima Mizuki Takubo Yurika Komura Yuki Maeda Miwa Sato Maki Zouda Prof. Tomoaki Tanase 《欧洲无机化学杂志》2023,26(9):e202200648
A new series of cationic heterodinuclear complexes, [M1M2Cl2(meso-dpmppp)(RNC)2]PF6 (M1=Ni, M2=Rh, R=tBu ( 1 a ); M1=Pd, M2=Rh, R=tBu ( 2 a ), Xyl ( 2 b ); M1=Pt, M2=Rh, R=tBu ( 3 a ), Xyl ( 3 b ); M1=Pd, M2=Ir, R=tBu ( 4 a )), supported by a tetradentate phosphine ligand, meso-Ph2PCH2P(Ph)(CH2)3P(Ph)CH2PPh2 (meso-dpmppp), were synthesized by stepwise reactions of meso-dpmppp with NiCl2 ⋅ 6H2O or MCl2(cod) (M=Pd, Pt), forming mononuclear metalloligands of [M1Cl2(meso-dpmppp)], and with [M2Cl(cod)]2 (M2=Rh, Ir) and RNC (R=tBu, Xyl) in the presence of [NH4][PF6]. The related neutral PdRh complex, [PdRhCl3(meso-dpmppp)(XylNC)] ( 5 ), was also prepared. The structures of 1 – 5 were determined by X-ray analyses to contain two square planar d8 metal centers with face-to-face arrangement, where meso-dpmppp supports M1 and M2 metal ions in cis/trans-P,P coordination mode, combining cis-{M1P2Cl2} and trans-{M2P2(CNR)2} units. Complexes 1 – 4 showed an intence characteristic absorption around 422–464 nm derived from RhI→RNC MLCT transition (HOMO→LUMO+1), which are influenced by changing M1 (NiII, PdII, PtII) metal ions since HOMO composed of dσ* orbitals appreciably destabilized by changing M1 from Ni to Pd, and Pt. The electronic structures of 1 a – 4 a were investigated on the basis of DFT calculations and NBO analyses to show weak but noticeable d8–d8 metallophilic interaction as empirical dispersion energy of 0.9–1.5 kcal/mol without M1–M2 covalent bonding interaction. In addition, 1 – 5 were utilized as catalysts for hydrosilylation of styrene, and the NiRh complex 1 a was found to show higher activity and chemo- and regioselectivity compared with 2 – 5 . 相似文献
8.
Highly Segregated Lamello‐Columnar Mesophase Organizations and Fast Charge Carrier Mobility in New Discotic Donor–Acceptor Triads 下载免费PDF全文
Prof. Dr. Ke‐Qing Zhao Ling‐Ling An Xiao‐Bo Zhang Wen‐Hao Yu Prof. Ping Hu Prof. Bi‐Qin Wang Jing Xu Dr. Qing‐Dao Zeng Dr. Hirosato Monobe Dr. Yo Shimizu Dr. Benoît Heinrich Dr. Bertrand Donnio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10379-10390
Four new donor–acceptor triads (D–A–D) based on discotic and arylene mesogens have been synthesized by using Sonogashira coupling and cyclization reactions. This family of triads consists of two side‐on pending triphenylene mesogens, acting as the electron‐donating groups (D), laterally connected through short lipophilic spacers to a central perylenediimide (PI), benzo[ghi]perylenediimide (BI), or coronenediimide (CI) molecular unit, respectively, playing the role of the electron acceptor (A). All D–A–D triads self‐organize to form a lamello‐columnar oblique mesophase, with a highly segregated donor–acceptor (D–A) heterojunction organization, consequent to efficient molecular self‐sorting. The structure consists in the regular alternation of two disrupted rows of triphenylene columns and a continuous row of diimine species. High‐resolution STM images demonstrate that PI‐TP2 forms stable 2D self‐assembly nanostructures with some various degrees of regularity, whereas the other triads do not self‐organize into ordered architectures. The electron‐transport mobility of CI‐TP2, measured by time‐of‐flight at 200 °C in the mesophase, is one order of magnitude higher than the hole mobility. By means of this specific molecular designing idea, we realized and demonstrated for the first time the so‐called p–n heterojunction at the molecular level in which the electron‐rich triphenylene columns act as the hole transient pathways, and the coronenediimide stacks form the electron‐transport channels. 相似文献
9.
Ruthenium‐Immobilized Periodic Mesoporous Organosilica: Synthesis,Characterization, and Catalytic Application for Selective Oxidation of Alkanes 下载免费PDF全文
Nobuhiro Ishito Dr. Hirokazu Kobayashi Dr. Kiyotaka Nakajima Yoshifumi Maegawa Dr. Shinji Inagaki Dr. Kenji Hara Prof. Dr. Atsushi Fukuoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15564-15569
Periodic mesoporous organosilica (PMO) is a unique material that has a crystal‐like wall structure with coordination sites for metal complexes. A Ru complex, [RuCl2(CO)3]2, is successfully immobilized onto 2,2’‐bipyridine (BPy) units of PMO to form a single‐site catalyst, which has been confirmed by various physicochemical analyses. Using NaClO as an oxidant, the Ru‐immobilized PMO oxidizes the tertiary C?H bonds of adamantane to the corresponding alcohols at 57 times faster than the secondary C?H bonds, thereby exhibiting remarkably high regioselectivity. Moreover, the catalyst converts cis‐decalin to cis‐9‐decalol in a 63 % yield with complete retention of the substrate stereochemistry. The Ru catalyst can be separated by simple filtration and reused without loss of the original activity and selectivity for the oxidation reactions. 相似文献
10.
Hiroki Hirai Kiichi Nakajima Soichiro Nakatsuka Kazushi Shiren Jingping Ni Shintaro Nomura Toshiaki Ikuta Takuji Hatakeyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13785-13789
The development of a one‐step borylation of 1,3‐diaryloxybenzenes, yielding novel boron‐containing polycyclic aromatic compounds, is reported. The resulting boron‐containing compounds possess high singlet‐triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light‐emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one‐step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron‐fused benzo[6]helicene. 相似文献