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991.
以4,4’-二苯醚二甲酸和4,4’-联吡啶为配体,通过调节水热反应的条件,如三乙胺的加入量,反应时间和反应温度等因素,可控合成了尺寸从10到250 μm的Ni(Ⅱ)、Co(Ⅱ)和Zn(Ⅱ)3种配合物微晶,其尺寸、形貌和结构用扫描电镜和X射线粉末衍射进行了表征和分析。光催化性能测试表明3种配合物对有机染料罗丹明B、甲基橙和亚甲基蓝均具有杰出的降解能力,且随着配合物晶粒尺寸减小其催化能力明显提高。最引人注目的是尺寸为30 μm的Ni(Ⅱ)配合物,其光催化性降解RhB染料的能力已超越纳米TiO2。此外,X射线粉末衍射表明,在一次光降解过程后配合物结构保持稳定,可作为重复利用的光催化剂。 相似文献
992.
The EcoRI restriction endonuclease requires one divalent metal ion in each of two symmetrical and identical catalytic sites to catalyse double-strand DNA cleavage. Recently, we showed that Cu2+ binds outside the catalytic sites to a pair of new sites at H114 in each sub-unit, and inhibits Mg2+-catalysed DNA cleavage. In order to provide more detailed structural information on this new metal ion binding site, we performed W-band (~94 GHz) and X-band (~9.5 GHz) electron spin resonance spectroscopic measurements on the EcoRI–DNA–(Cu2+)2 complex. Cu2+ binding results in two distinct components with different gzz and Azz values. X-band electron spin echo envelope modulation results indicate that both components arise from a Cu2+ coordinated to histidine. This observation is further confirmed by the hyperfine sub-level correlation results. W-band electron nuclear double resonance spectra provide evidence for equatorial coordination of water molecules to the Cu2+ ions. 相似文献
993.
The metal-organic frameworks (three-dimensional porous coordination polymers) [Zn4O(Me4BPDC)3] × 9 DMF, 2 · 9 DMF and [Cu2(Me4BPDC)2] × 9 DMF, 3 · 9 DMF are representatives of the classical Zn-IRMOF series and Cu paddle-wheel complexes with H2Me4BPDC = 2,2′,6,6′-tetramethyl-4,4′-biphenyldicarboxylic acid, 1. The dicarboxylate linker of 1 is a representative of the non-planar biphenyl ligand family, known as an efficient scaffold for chiral molecules. There is a 90° twist angle between the phenyl rings in 1, dictated by the methyl groups, which leads to assembly of doubly interpenetrated pcu-a (in 2) and nbo-a (in 3) nets under low temperature solvothermal conditions in dimethylformamide (DMF). Activation by degassing (to yield 2), exchange with methanol or tetrahydrofuran and subsequent evacuation at elevated temperatures (to yield 3I) gave materials with BET surface areas of 1735 m2/g (2) and 1041 m2/g (3I). Adsorbed quantities of H2 were 1.26 wt% (2) and 1.02 wt% (3I) (77 K, 1 bar), CO2 30.8 cm3/g (2) and 50 cm3/g (3I) (273 K, 1 bar) and CH4 12.9 cm3/g (2) and 11.4 cm3/g (3I) (273 K, 1 bar). The H2 and CO2 sorption values for 2 are similar to those of MOF-5 (IRMOF-1) with its almost doubled BET surface area. An increase is found concerning the adsorbed amounts of N2, H2, and CO2 for 3I compared to related doubly interpenetrated nbo-a-type MOF-601, MOF-602, MOF-603 ([Cu2L2] with L = 2,2′-R2-4,4′-biphenyldicarboxylate, R = CN, Me, I, respectively). 相似文献
994.
以手性对称的Schiff碱为配体,合成了手性镍配合物[Ni2(salen)2(1)],其结构经X-单晶射线衍射和元素分析表征。1属单斜晶系,C2空间群,晶胞参数a=25.060(5)A,b=13.508(3),c=11.938(2),α=90(3)°,β=104.82(3)°,γ=90(3)°,V=3 906.7(14)3,Z=4,Mr=828.24,Dc=1.429 g.cm-3,F(000)=1 808,μ=1.027 mm-1,GOF=1.068,R1=0.051 0,wR2=0.128 9。在1的分子结构中,环己胺和苯环之间通过分子间CH┈π作用形成二维结构。 相似文献
995.
采用Oniom方法(B3LYP/LANL2DZ∶PM3)对脲基取代的二(9-冠-3)杯[4]芳烃衍生物(H)与离子对Na+X-(X=F-,Cl-,Br-)的包合作用进行了理论研究.在上述体系中存在2种包合方式:一是阴、阳离子在包合物中是分离的,阴离子与主体分子的上沿主要以N—H…X-氢键作用;二是阴、阳离子在包合物中存在明显的离子配对作用,阴离子主要以阳离子的配对作用存在.通过对包合物Na+X-/H的结构参数、自然键轨道(NBO)以及结合能分析可知,第1种包合方式更有利.研究表明脲基取代的二(9-冠-3)杯[4]芳烃衍生物可成为有效的离子对识别受体,研究结果进一步加深了杯芳烃类受体对离子对识别机理的认识,为实验上设计合成新型离子对受体提供了理论依据. 相似文献
996.
Space division with red cubes: Doping metal-organic frameworks with another metal component gives a further opportunity to tune their properties. Recent work successfully introduced europium into the inorganic nodes of frameworks. Although the doping element does not affect the framework topology, highly improved emissive performance was measured thanks to the intrinsic red emission of europium. 相似文献
997.
998.
AE Carpenter GW Margulieux MD Millard CE Moore N Weidemann AL Rheingold JS Figueroa 《Angewandte Chemie (International ed. in English)》2012,51(37):9412-9416
A break with tradition: The cation, [Ph(3) P?N?PPh(3) ](+) ([PPN](+) ), was found to provide a stabilizing η(2) -arene interaction to the coordinatively unsaturated, tris-isocyanide monoanion, [Co(CNAr(Mes2) )(3) ](-) (Ar(Mes2) =2,6-(2,4,6-Me(3) C(6) H(2) )C(6) H(3) ); Co=purple, N=light purple, and P=orange). The resulting zwitterion is a source of [Co(CNAr(Mes2) )(3) ](-) anions, performing nucleophilic additions, carbon-element bond activations, and multistep decarbonylations. 相似文献
999.
1000.
Dr. Delphine Crozet Dr. Aitor Gual Dr. David McKay Dr. Chiara Dinoi Dr. Cyril Godard Prof. Martine Urrutigoïty Dr. Jean‐Claude Daran Prof. Laurent Maron Prof. Carmen Claver Prof. Philippe Kalck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7128-7140
The reactivity of [Rh(CO)2{(R,R)‐Ph? BPE}]BF4 ( 2 ) toward amine, CO and/or H2 was examined by high‐pressure NMR and IR spectroscopy. The two cationic pentacoordinated species [Rh(CO)3{(R,R)‐Ph? BPE}]BF4 ( 4 ) and [Rh(CO)2(NHC5H10){(R,R)‐Ph‐BPE}]BF4 ( 8 ) were identified. The transformation of 2 into the neutral complex [RhH(CO)2{(R,R)‐Ph? BPE}] ( 3 ) under hydroaminomethylation conditions (CO/H2, amine) was investigated. The full mechanisms related to the formation of 3 , 4 and 8 starting from 2 are supported by DFT calculations. In particular, the pathway from 2 to 3 revealed the deprotonation by the amine of the dihydride species [Rh(H)2(CO)2{(R,R)‐Ph? BPE}]BF4 ( 6 ), resulting from the oxidative addition of H2 on 2 . 相似文献