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81.
82.
(N,N,N′,N′ -tetramethylethylendiamine) di(tert-butyl)aluminium Cations — Molecular Structure of [(Me3C)2Al(TMEDA)]⊕[(Me3C)2AlBr2]? Dimeric di(tert-butyl)aluminium halides (Me3C)2AlX (X = Cl, Br) react with N,N,N′,N′ -tetramethylethylendiamine (TMEDA) to give three compounds: the salt-like [(Me3C)2Al(TMEDA)]⊕[(Me3C)2AlX2]? 1 , characterized by crystal structure determination, and [(Me3C)2Al(TMEDA)]⊕X? 3 both with chelating amine, and the more covalent, pentane soluble (Me3C)2AlX(TMEDA) 2 with TMEDA bound by only one nitrogen atom. The reaction resembles the symmetrical and unsymmetrical cleavage of diborane(6). 3 (X = Cl) is also formed by treatment of 1 with boiling n-hexane in the presence of TMEDA over a period of 24 hours, while for X = Br the more covalent 2 is the main product under similar conditions. In solution 2 decomposes slowly yielding different products in dependency of the solvent: in benzene 3 and in n-pentane 1 are formed. 相似文献
83.
Strategic Utilization of Multifunctional Carbene for Direct Synthesis of Carboxylic–Phosphinic Mixed Anhydride from CO2
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Prof. Dr. Yoichi Hoshimoto Takahiro Asada Dr. Sunit Hazra Takuya Kinoshita Panukorn Sombut Dr. Ravindra Kumar Prof. Dr. Masato Ohashi Prof. Dr. Sensuke Ogoshi 《Angewandte Chemie (International ed. in English)》2016,55(52):16075-16079
Direct synthesis of carboxylic–phosphinic mixed anhydrides has been achieved by treating carbon dioxide with N‐phosphine oxide‐substituted imidazolylidenes (PoxIms) that contain both nucleophilic carbene and electrophilic phosphorus moieties. This novel mixed anhydride was efficiently derivatized into an ester, an amide, and an unsymmetrical ketone via transformation into its corresponding imidazolium salt followed by a dual substitution reaction. The presented work used well‐designed multifunctional carbene reagents to establish a novel utility for carbon dioxide in organic synthesis. 相似文献
84.
不对称双二茂铁脲衍生物的合成、表征及电子传递性质 总被引:2,自引:0,他引:2
以二茂铁为原料,通过多步反应,首先合成了对称的桥联双二茂铁脲(5),再将其与胱胺反应,合成了一种新的不对称桥 联双二茂铁脲衍生物MeOOC-Fc-NH-CO-NH-Fc-CO-NH-(CH2)2-S-S-(CH2)2-NH2 (7)(Fc:二茂铁)。对目标产物进行了红外、紫外、1H NMR和MS表征;由于目标化合物7含有不对称的二茂铁脲这一特殊结构,采用循环伏安(CV)方法对化合物7的电子迁移特性进行了研究。结果表明2个二茂铁之间通过脲键传递电子,从而使2个二茂铁基团可以分别被氧化,它们的氧化电位差ΔEo?为181 mV,它们之间的稳定常数Kc为1 145。相对于对称的二茂铁脲(5)(ΔEo?=140 mV,Kc=207),这种不对称结构分子中2个二茂铁之间电子间的相互作用增强。 相似文献
85.
MCM-41固载不对称席夫碱Cu(Ⅱ)配合物的制备及催化性能 总被引:2,自引:0,他引:2
用多步接枝法将不对称席夫碱Cu(Ⅱ)配合物Cu(CBP-PHEN-Sal)共价联接到介孔分子筛MCM-41的表面。对得到的材料用XRD、FTIR、DR UV-Vis、氮气吸附、元素分析和ICP进行了表征。结果表明,不对称席夫碱Cu(Ⅱ)配合物被成功地固载于MCM-41的孔道中,而且固载后MCM-41的结构特征保持不变。考察了固载催化剂在烯烃液相氧化中的催化活性。以叔丁基过氧化氢为氧化剂,在苯乙烯氧化中,固载催化剂比配合物表现出更高的催化活性。同时,研究了反应条件,例如溶剂、催化剂用量、温度和反应时间对固载催化剂催化性能的影响。 相似文献
86.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(6):666-672
A new unsymmetrical s‐tetrazine derivative, namely 4‐({2‐[6‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐1,2,4,5‐tetrazin‐3‐yl]hydrazin‐1‐ylidene}methyl)phenol (DPHM), C14H14N8O, was synthesized based on 3‐(3,5‐dimethylpyrazol‐1‐yl)‐6‐hydrazinyl‐s‐tetrazine (DPHT). The structure was characterized by elemental analysis and single‐crystal X‐ray diffraction. Crystal structure determination shows that DPHM crystallizes in the monoclinic P21/c space group with high coplanarity and a zigzag layered structure. In addition, its thermal behaviour was investigated by DSC and TG–DTG methods. The thermal safety of DPHM was evaluated by self‐accelerating decomposition temperature (TSADT), critical temperature of thermal explosion (Tb), entropy of activation (ΔS), enthalpy of activation (ΔH) and free energy of activation (ΔG). Meanwhile, the kinetic parameters and specific heat capacity of DPHM were also determined. The results show that DPHM has better stability and detonation properties than 3‐(2‐benzylidenehydrazin‐1‐yl)‐6‐(3,5‐dimethylpyrazol‐1‐yl)‐s‐tetrazine (DAHBTz), due to the introduction of a hydroxy group, which increases the number of hydrogen‐bond interactions and improves the stability and density of DPHM. This study demonstrates that the performance of an explosive can be optimized through structural modification. 相似文献
87.
Yaqian Zhong Deyu Liu Kaili Zhang Yonghai Li Mingliang Sun Liangmin Yu Feng Li Huizhou Liu Renqiang Yang 《Journal of polymer science. Part A, Polymer chemistry》2018,56(24):2762-2770
As a promising electron-deficient (acceptor) unit, fluorinated benzotriazole (TAZ) was used widely to construct wide bandgap polymers for nonfullerene polymer solar cells (NF-PSCs). However, due to the S…F noncovalent interaction, the unit show good planarity and strong aggregation, which was not beneficial for the blend with the elongated nonfullerene acceptors. Here, we tried to choose new donor polymers to match with TAZ unit, which was expected to destroy the interchain aggregation of polymer and form favorable morphology of blends. Two new wide-bandgap polymers PBDTsPhPh-T1 and PBDTsThPh-T1 based on the unsymmetrical benzodithiophene (BDT) units with a benzene ring as lever arms were synthesized. As a result, these two polymers blend well with nonfullerene acceptor (ITIC). And then, PBDTsPhPh-T1 and PBDTsThPh-T1-based devices exhibit the decent photovoltaic properties with high power conversion efficiencies of 8.85 and 9.34%, respectively. The work demonstrates that the unsymmetrical BDT units could be outstanding for building donor materials toward high-performance NF-PSCs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2762–2770 相似文献
88.
A new kind of thiazole-containing unsymmetrical ortho-diamine monomer,2-amino-5-[4-(2’- aminophenoxy)phenyl]-thiazole(o-AAPPT),was synthesized by four steps,using 4-hydroxyacetophenone as starting material.A novel thiazole-containing polyimide was prepared from the resulting diamine o-AAPPT with BTDA via a conventional one-step method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal and thermo-oxidative stability. 相似文献
89.
Introduction Manystructuralelements(pole,plate,shell)withunevenandvariablethicknessarewidely usedinallkindsofengineeringfields.Engineerscansavematerialswhentheydesignbecause theseelementshavebetteroptimizedshapeofstructuralfeature,butthisaddsdifficultytotheanalysisoftheirmechanicalcapability.Manypreviouspapers[1-4]havesolvedtheproblemof symmetricalaxis,butnobodyhassolvedtheunsymmetricalnonlineardeformationproblemof circularthinplatewithvariablethicknessandunsymmetricalaxisuptonow,afewworkonly … 相似文献
90.
Kishalay Bhar Sumitra Das Smita Satapathi Partha Mitra Joan Ribas Barindra Kumar Ghosh 《Polyhedron》2010
Two neutral nickel(II) coordination polymers [Ni(en)(dca)2]n (1) and [Ni(dmen)(dca)2]n (2) (en = ethylenediamine; dmen = N,N-dimethylethylenediamine; dca = dicyanamide) have been synthesized and X-ray crystallographically characterized. Each nickel(II) center in 1/2 adopts a distorted octahedral coordination environment with a NiN6 chromophore ligated by two amine N atoms of the bidentate amine (en/dmen) and four nitrile N atoms of μ1,5 bridged dca. The metal(II) centers are connected with each other through single μ1,5 M–NCNCN–M bridges, resulting in a 2D layer structure with a (4,4) topology in 1 and a 3D network of topology (6,6) in 2. Multiple lateral N–H···N and C–H···N hydrogen bondings promote dimensionality. The magnetic susceptibility results of 1 and 2 at very low temperature support the zero-field splitting effect of the nickel(II) ions. 相似文献