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161.
Lianjun Shi Keri A. Boduch‐Lee John T. Henssler Eric J. Beckman Toby M. Chapman 《Journal of polymer science. Part A, Polymer chemistry》2004,42(19):4994-5004
N‐alkyl‐N‐vinylformamide monomers (alkyl: n‐butyl, hexyl, decyl, and dodecyl) are synthesized in two steps: first, preparation of N‐vinylformamide potassium salt by the reaction of N‐vinylformamide (NVF) with potassium t‐butoxide, then reaction with alkyl bromide. All four monomers are liquid and are characterized by IR, 1H NMR, 13C NMR, and mass spectra. They exist as rotomers in solution and a 2D NOE experiment on the N‐hexyl containing polymer shows the E isomer to be favored. The polymerizability of the four monomers is from good to fair, depending upon the length of alkyl chain on the N‐atom‐‐the longer the chain length, the lower lower the polymerizability of monomer. The hydrolysis of poly(N‐hexyl‐N‐vinylformamide) and poly(N‐dodecyl‐N‐vinylformamide) under acidic and basic conditions was examined. Studies show that hydrolytic cleavage of formyl groups of poly (N‐alkylated‐N‐vinylformamide) depends on the hydrophobicity of the alkyl substituent on the N‐atom under acidic conditions; both polymers were hydrolyzed to only a minor extent under alkaline conditions. The N‐alkylated monomers can copolymerize with NVF and demonstrate amphiphilic properties. The copolymers demonstrate a critical aggregation concentration above which they can solubilize a water insoluble dye; the N‐hexyl containing copolymer stabilizes a castor oil‐in‐water emulsion. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4994–5004, 2004 相似文献
162.
Computational and cyclic voltammetry studies have been used to explore electrochemical reductions of three helically chiral homologues, 22+, 32+, and 42+, of methyl viologen. Thermochemical-electrochemical cycles are used as frameworks to describe the reversible redox properties of these helically chiral viologens as novel reversible four-sided ECEC (Electron-transfer Chemical-reaction Electron-transfer Chemical-reaction) processes. 相似文献
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Sang Kyu Park Hong Sun Hyunjoong Chung Bijal B. Patel Fengjiao Zhang Daniel W. Davies Toby J. Woods Kejie Zhao Ying Diao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):13104-13112
Like silicon, single crystals of organic semiconductors are pursued to attain intrinsic charge transport properties. However, they are intolerant to mechanical deformation, impeding their application in flexible electronic devices. Such contradictory properties, namely exceptional molecular ordering and mechanical flexibility, are unified in this work. We found that bis(triisopropylsilylethynyl)pentacene (TIPS-P) crystals can undergo mechanically induced structural transitions to exhibit superelasticity and ferroelasticity. These properties arise from cooperative and correlated molecular displacements and rotations in response to mechanical stress. By utilizing a bending-induced ferroelastic transition of TIPS-P, flexible single-crystal electronic devices were obtained that can tolerate strains (ϵ) of more than 13 % while maintaining the charge carrier mobility of unstrained crystals (μ>0.7 μ0). Our work will pave the way for high-performance ultraflexible single-crystal organic electronics for sensors, memories, and robotic applications. 相似文献
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The rate law ? d[O3]/ dt = k1[A][O3] + k3[A][O3]2/ (k4 + k5[O2]) has been found to obtain for the reaction of ozone with allene and with 1,2-butadiene. We now find that this rate law also applies to the reaction of ozone with ethylene and presumably with all lower alkenes. This generalizes the inhibiting effect of oxygen and accounts for the simplifed rate law found in the presence of excess oxygen. Oxygen itself is a product of the ozone–ethylene reaction, and we find that as [O3]0 increases, the (O2 formed)/(O3 used) ratio approaches 1.5. Values of k1, k3/k5 for ethylene are compared with those for allene, 1,3-butadiene, and propene. A generalized mechanism is postulated for the reaction of ozone with alkenes involving a chain sequence that produces oxygen and which accounts for the observed rate law. A specific mechanism is postulated for the reaction of O3 with ethylene, and the thermochemistry of the chain sequence is examined in detail. 相似文献
170.
Manson JL Woods TJ Lapidus SH Stephens PW Southerland HI Zapf VS Singleton J Goddard PA Lancaster T Steele AJ Blundell SJ 《Inorganic chemistry》2012,51(4):1989-1991
Square-planar S = 1/2 Ag(II) ions in polymeric Ag(nic)(2) are linked by bridging nic monoanions to yield 2D corrugated sheets. Long-range magnetic order occurs below T(N) = 11.8(2) K due to interlayer couplings that are estimated to be about 30 times weaker than the intralayer exchange interaction. 相似文献