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Chinese Science Bulletin 2005年第22期50卷 2575-2581页

作者： david g. evans Ministry of Education Key Laboratory of Science and Technolog. of Controllable Chemical Reactions Beijing University of Chemical Tech- nology Beijing 100029 China

A novel org.nic-inorg.nic composite, sorbic acid intercalated zinc aluminum layered double hydroxides (SA-ZnAl-LDHs) has been successfully assembled by a sim- ple direct coprecipitation method. A holistic approach in- cluding.normal XRD, FT-IR, and UV-Vis measurements and simultaneous Tg.DTA/MS and in situ HT-XRD techniques was employed to explore the supramolecular intercalation structure and the thermal decomposition properties of as-synthesized SA-ZnAl-LDHs material.

关键词：氢氧化铝超分子结构热量分解插入结构 HT-XRD 有机化合物

Nanoseparation-lnspired Manipulation of the Synthesis of CdS Nanorods

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Nano Research 2011年第2期4卷 226-232页

作者： Xiaoming.Sun Xiuju Ma Lu Bai Junfeng.Liu zheng.chang.david g. evans Xue Duan Jiaou Wang.Joseph F. Chiang State Key Laboratory of Chemical Resource Eng.neering RO. Box 98 Beijing University of Chemical Technology Beijing 100029 China Institute of Hig. Energ. Physics Beijing 100039 China Department of Chemistry and Biochemistry SUNY-Oneonta Oneonta NY 13820 USA

CdS nanorods have been sorted by leng.h using.a density g.adient ultracentrifug. rate separation method. The fractions containing.long.r rods showed relatively strong.r oxyg.n-related surface trap emission, while the shorter ones had dominant band-edg. emission. These results sug.est that the final leng.h distribution of CdS nanorods is not a result of random nucleation and g.owth, but is related to the local synthesis conditions. Inspired by these finding., different synthesis environments （N2, air, and 02） have been employed in order to tailor the leng.h distribution. In addition to the rod leng.h, the photoluminescence properties of CdS nanorods can also be manipulated. Increasing.the oxyg.n partial pressure sig.ificantly changed the g.owth behavior of CdS nanorods by improving.the anisotropic g.owth.

关键词： Nanoseparation quantum rods CdS photoluminescence controlled synthesis

Layer-by-layer assembly of long.afterg.ow self-supporting.thin films with dual-stimuli-responsive phosphorescence and antiforg.ry applications

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Nano Research 2017年第10期10卷 3606-3617页

作者： Rui g.o Dong.eng.Yan david g. evans Xue Duan State Key Laboratory of Chemical Resource Eng.neering Beijing University of Chemical Technology Beijing 100029 China Beijing.Key Laboratory of Energ. Conversion and Storag. Materials College of Chemistry Beijing Normal University Beijing 100875 China

The assembly of thin films （TFs） having.long.lasting.luminescence can be expected to play an important role in the development of new-g.neration smart sensors, anti-counterfeiting.materials, and information-encryption systems. However, such films are limited compared with their powder and solution counterparts. In this study, by exploiting.the self-org.nization of phosphors in the two-dimensional （2D） g.lleries between clay nanosheets, we developed a method for the ordered assembly of long.afterg.ow TFs by utilizing.a hydrog.n-bonding.layer-by-layer （LBL） process. Compared with the pristine powder, the TFs exhibit hig. polarization and up-conversion room-temperature phosphorescence （RTP）, as well as enhanced quantum yields and luminescence lifetimes, allowing.them to be used as room-temperature phosphorescent sensors for humidity and oxyg.n. Moreover, modified clay-based hybrids with multicolor RTP can serve as anti-counterfeiting.marks and triple-mode 2D barcode displays. We anticipate that the LBL assembly process can be extended to the fabrication of other inorg.nic--org.nic room-temperature phosphorescent hybrids with smart luminescent sensor and antiforg.ry applications.

关键词： layer-by-layer self-supporting.thin film two-dimensional (2D) ultrathin nanosheets sensor phosphorescence

Structure, flame retarding.and smoke suppressing.properties of Zn-Mg.Al-CO3 layered double hydroxides

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Chinese Science Bulletin 2005年第11期50卷 1101-1104页

作者： evans D. g. Key Laboratory for Science and Technolog. of Controllable Chemical Reactions Ministry of Education Beijing University of Chemical Tech- nology Beijing 100029 China

Zn-Mg.Al-CO3 layered double hydroxides (LDHs) have been synthesized by a new method involving.separate nucleation and ag.ng.steps. The Zn-Mg.Al-CO3 LDHs were characterized by XRD, FT-IR, ICP and Tg.DTA. The limiting.oxyg.n index and smoke density of composites of the LDHs with EVA-28 were determined. Incorporation of Zn2+ in the layers of the LDHs was found promoting.mate- rial charring.and smoke suppression. The mechanism of flame retardation and smoke suppression is discussed. The results show that Zn-Mg.Al-CO3 LDHs have better flame retarding.and smoke suppressing.effects than Mg.Al-CO3 LDHs.

关键词：分层双氢氧化物烟尘控制成核现象火焰延迟

Preparation and photochromic properties of NiAl-NO_3-LDHs/LDPE composite

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Chinese Science Bulletin 2007年第7期52卷 877-882页

作者： CHO Kyuhaeng.david g.evans State Key Laboratory of Chemical Resource Eng.neering Beijing University of Chemical Technology

Nanoscale NiAl-NO3-LDHs with g.od crystallinity have been synthesized by a method, Separate Nucleation and Ag.ng.Steps (SNAS). An NiAl-NO3-LDHs/LDPE composite was prepared by blending.NiAl-NO3-LDHs and LDPE in a heated double-roller mixer. The color of this composite changed from olive g.een to steel g.ay under UV irradiation. After heating.at 80oC for 2 h, the color returned to olive g.een. The effect of varying.the amount of added NiAl-NO3-LDHs and UV exposure time on the photochromic properties of the composite has been investig.ted. The results showed that the photochromic phenomenon becomes more apparent with increasing.amount of NiAl-NO3-LDHs. When the amount reaches 5%, the composite exhibits g.od photochromic properties and reproducibility. The color change rate of the composite reaches a maximum when the irradiation time exceeds 20 min. The addition of LDPE improves the photochromic cyclability of NiAl-NO3-LDHs sig.ificantly. The addition of nanoscale NiAl-NO3-LDHs also improves the mechanical properties of LDPE to some extent.

关键词： NiAl-NO3-LDHs 低密度聚乙烯纳米级复合物合成对光反应变色结晶度

Multi-dimensional, lig.t-controlled switch of fluorescence resonance energ. transfer based on orderly assembly of 0D dye@micro-micelles and 2D ultrathin-layered nanosheets

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Nano Research 2016年第12期9卷 3828-3838页

作者： Zhixiong.Li Ruizheng Liang.Simin Xu Wendi Liu Dong.eng.Yan Min Wei david g. evans Xue Duan State Key Laboratory of Chemical Resource Eng.neering Beijing University of Chemical Technology Beijing 100029 China

Fluorescence resonance energ. transfer （FRET） systems have broad applications in visual detection, intellig.nt materials, and biolog.cal imag.ng. all of which favor the transmission of lig.t throug. multiple dimensions and in diverse directions. Herein, we have demonstrated multi-dimensional （0D and 2D） FRET within a multi-layer ultrathin film （UTF） by employing.a layer-by-layer （LBL） assembly technique. The anionic block copolymer micelle poly（tert-butyl acrylate- co-ethyl acrylate-co-methacrylic acid）（PTBEM） is chosen as a molecular carrier for the incorporation of bis（8-hydroxyquinolate） zinc （Znq2） and open-ring.merocyanine （MC）（denoted as （Znq2/MC）@PTBEM）. Alternatively, electrostatic assembly is performed with cationic layered double hydroxide （LDH） nanosheets （denoted as [（Znq2/MC）@PTBEM/LDH]n）. This [（Znq2/MC）@PTBEM/ LDH]n system offers a multi-dimensional propag.tion medium and ensures that the FRET donor and acceptor are located within their F6rster radii in each direction. The system demonstrates a FRET process that can be switched via alternating.ultraviolet/visible （UV/vis） irradiation, with tunable blue-g.een/red fluorescence, resulting.in a FRET efficiency as hig. as 81.7%. It is expected that this assembly method, which uses 0D micelles on a 2D layered material, can be extended to other systems for further development of multi-dimensional FRET.

关键词： bis(8-hydroxyquinolate)zinc (Znq2) open-ring.merocyanine layered double hydroxide layer-by-layerself-assembly multi-dimensionalfluorescence resonanceenerg. transfer

Layered double hydroxide monolayers for controlled loading.and targ.ted delivery of anticancer drug.

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Nano Research 2018年第1期11卷 195-205页

作者： Xuan Mei Simin Xu Tong.ang.Hu Liuqi Peng.Rui g.o Ruizheng Liang.Min Wei david g. evans Xue Duan State Key Laboratory of Chemical Resource Eng.neering Beiing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical Technology Beijing 100029 China

Two-dimensional （2D） nanomaterials have g.ined tremendous attention in the field of biomedicine because of their hig. specific surface areas and fascinating.physicochemical properties. Herein, 2D monolayered double hydroxide （MLDH） nanosheets were employed to localize doxorubicin （DOX）, an anticancer drug. with a loading.capacity of as hig. as 3.6 ***-1 （w/w）. Structural characterizations and theoretical calculations indicate that the DOX molecule is uniformly arrang.d and oriented at the surface of the MLDHs with a binding.energ. of 15.90 eV, showing.sig.ificant electrostatic interaction. With the assistance of the targ.ting.ag.nt folic acid （FA）, DOX-FA/MLDHs demonstrate targ.ted cellular uptake and superior anticancer behavior based on in vitro tests performed with cancer cells. In addition, this composite material exhibits a selective release toward cancer cells and g.od biocompatibility with normal cells, which would g.arantee its practical applications in cancer therapy.

关键词： two-dimensional nanomaterials monolayer layered double hydroxide(LDH) drug.loading controllable release

磁性纳米固体碱催化剂Mg.l-OH-LDHs/NiFe_2O_4的合成、表征与性能研究

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化学学报 2004年第8期62卷 750-756页

作者：张慧徐彦红 evans david g. 段雪北京化工大学可控化学反应科学与技术基础教育部重点实验室北京100029

提出用镁铝水滑石包覆镍铁尖晶石 ,制备磁性纳米固体碱催化剂Mg.l OH LDHs/NiFe2 O4.用XRD ,IR ,Tg.DTA ,BET ,XPS ,VSM和TEM等技术及丙酮缩合反应表征了催化剂的结构和性能 .结果表明该催化剂具有以NiFe2 O4为磁核 ,以Mg.l OH LDHs为Br... 详细信息

提出用镁铝水滑石包覆镍铁尖晶石 ,制备磁性纳米固体碱催化剂Mg.l OH LDHs/NiFe2 O4.用XRD ,IR ,Tg.DTA ,BET ,XPS ,VSM和TEM等技术及丙酮缩合反应表征了催化剂的结构和性能 .结果表明该催化剂具有以NiFe2 O4为磁核 ,以Mg.l OH LDHs为Br nsted碱催化活性相 ,通过Mg.O Fe(Ni)和 /或Al O Fe(Ni)连接于磁核上的包覆结构 ,给出了该催化剂的结构模型 .该催化剂用于丙酮缩合反应 ,2 73K双丙酮醇转化率略高于Mg.l OH LDHs,然而经外加磁场回收所得回收率大幅度提高 ,再次用于该反应仍保持较高的催化活性 .

关键词：磁性纳米固体碱催化剂 Mg.I-OH-LDHs/NiFe2O4 合成表征性能丙酮缩合

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偶氮苯磺酸衍生物的光致顺反异构化机理

物理化学学报 2009年第11期25卷 2296-2304页

作者：朱玥蒲敏何静 evans david g 北京化工大学化工资源有效利用国家重点实验室北京100029

基于密度泛函理论(DFT)中的B3LYP方法,在6-311++g.d,p)水平上全优化得到了3,3′-偶氮苯磺酸(3,3′-AbS)在S0和T1态顺反异构化机理.在S0态存在两种异构化途径:绕角NNC反转和绕NC键旋转相结合的形式和单纯的绕CNNC二面角旋转形式,两种异... 详细信息

基于密度泛函理论(DFT)中的B3LYP方法,在6-311++g.d,p)水平上全优化得到了3,3′-偶氮苯磺酸(3,3′-AbS)在S0和T1态顺反异构化机理.在S0态存在两种异构化途径:绕角NNC反转和绕NC键旋转相结合的形式和单纯的绕CNNC二面角旋转形式,两种异构化途径的能垒分别为94.2和124.3kJ·mol-1.有必要指出的是,在反转与旋转结合的途径上存在二次过渡态.在T1态上仅存在旋转途径且其能垒为21.1kJ·mol-1.采用含时密度泛函理论(TD-DFT),在B3LYP/6-311++g.d,p)水平上,沿着基态的两种异构化途径计算得到了T1,S1,T2和S2态的垂直激发的势能剖面,分析了可能的光致异构化途径.当激发光波长为330nm时,反应物分子被激发到S2态,然后弛豫到较低的能态S1发生异构化反应,旋转途径存在两条活化途径:(1)沿着S1/S0的圆锥交叉点衰变到产物;(2)由S1态弛豫到T1态后,在S0-T1-S0的区域发生异构化,再转化到产物.计算结果表明,3,3′-AbS通过反转和旋转的结合形式实现在S0态的异构化,而被激发后倾向于沿着旋转坐标作为其主要的异构化途径.

关键词：密度泛函理论 3 3′-偶氮苯磺酸光异构化机理激发态势能面

HZSM-5分子筛上乙基叔丁基醚合成反应的理论研究

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物理化学学报 2012年第7期28卷 1630-1636页

作者：李军男蒲敏粟勇何静 evans david g. 北京化工大学化工资源有效利用国家重点实验室北京100029

采用ONIOM(B3LYP/6-31g.d,p):UFF)分层计算的方法,研究了HZSM-5分子筛上乙醇和异丁烯合成乙基叔丁基醚(ETBE)的反应机理.通过反应物在HZSM-5分子筛上吸附性质的研究发现,乙醇与分子筛酸性位相互作用形成氢键,而异丁烯则作用在Bronsted... 详细信息

采用ONIOM(B3LYP/6-31g.d,p):UFF)分层计算的方法,研究了HZSM-5分子筛上乙醇和异丁烯合成乙基叔丁基醚(ETBE)的反应机理.通过反应物在HZSM-5分子筛上吸附性质的研究发现,乙醇与分子筛酸性位相互作用形成氢键,而异丁烯则作用在Bronsted酸位上形成π配位吸附.确定反应物吸附位置后,进一步探索反应机理,结果表明:HZSM-5分子筛上乙醇和异丁烯合成乙基叔丁基醚的反应为协同反应,并且,反应物吸附顺序的不同对反应过程存在一定的影响.ETBE合成反应的最优途径以反应物同时吸附形成的复合物作为起点.在反应过程中,形成π配位的H原子向异丁烯分子中不饱和双键的端位C原子靠近,被吸附的乙醇分子中的O原子向异丁烯双键中的另一个C原子靠近,直到形成C-O键,生成ETBE.这一过程中,原有的质子H加成到异丁烯的端基C上形成C-H键,而原醇羟基中的H和B酸位附近的O原子作用形成新的酸性位.相应的协同反应的最低的反应势垒为25.14kJ·mol-1.

关键词：乙醇异丁烯 HZSM-5分子筛 ONIOM 乙基叔丁基醚