Tunable Linear and Nonlinear Optical Properties from Room Temperature Phosphorescent Cyclic Triimidazole-Pyrene Bio-Probe

Organic materials with multiple emissions tunable by external stimuli represent a great challenge. TTPyr, crystallizing in different polymorphs, shows a very rich photophyisics comprising excitation-dependent fluorescence and phosphorescence at ambient conditions, and mechanochromic and thermochromic behavior. Transformation among the different species has been followed by thermal and X-ray diffraction analyses and the emissive features interpreted through structural results and DFT/TDDFT calculations. Particularly intriguing is the polymorph TTPyr(HT), serendipitously obtained at high temperature but stable also at room temperature, whose non-centrosymmetric structure guarantees an SHG efficiency 10 times higher than that of standard urea. Its crystal packing, where only the TT units are strongly rigidified by π-π stacking interactions while the Pyr moieties possess partial conformational freedom, is responsible for the observed dual fluorescence. The potentialities of TTPyr for bioimaging have been successfully established.     

基于非靶向代谢组学的茄梨和红茄梨成熟期果皮代谢产物的差异分析

为了探究西洋梨品种茄梨及其红色芽变红茄梨成熟期果皮代谢产物差异,采用超高效液相色谱-质谱联用技术,对茄梨和红茄梨成熟期果皮进行非靶向代谢组学研究。通过主成分分析和正交偏最小二乘判别分析,构建了多变量统计分析模型,结合模型和变量重要性投影与最大差异倍数值,基于精确质量数、二级碎片以及同位素分布,使用PMDB(Plant Metabolome Database)数据库进行定性,筛选并鉴定出茄梨和红茄梨果皮中显著性变化(P<0.05, VIP(variable importance in project)≥1)的差异代谢物有83种,主要包括酚酸类、黄酮类和氨基酸类物质,涉及类黄酮代谢、氨基酸代谢、苯丙烷类代谢等代谢途径,其中53种物质含量上调,30种物质表达下调。通过KEGG(Kyoto Encyclopedia of Genes and Genomes)数据库进一步对差异代谢物质进行通路富集分析,差异代谢物主要分布在20条代谢途径中,P<0.05的代谢途径有6条,分别是类黄酮生物合成、黄酮和黄酮醇生物合成、苯丙烷生物合成、丁酸酯代谢、苯丙氨酸代谢、酪氨酸代谢。这些差异代谢物的变化可能是导致茄梨和红茄梨果皮色泽不同的原因。该研究从植物代谢组学角度初步揭示了茄梨和红茄梨成熟期果皮的代谢产物差异性。     

KIT-6负载CeO2催化CO2和甲醇合成碳酸二甲酯

采用不同老化温度(80、100、120和150℃)合成了一系列KIT-6载体,并通过浸渍法制备了相应的CeO_2/KIT-6催化剂。结合X射线衍射、N_2物理吸附、NH_3程序升温脱附、CO_2程序升温脱附、透射电子显微镜、傅里叶变换红外光谱和X射线光电子能谱等表征结果,详细考察了老化温度对KIT-6结构以及CeO_2/KIT-6催化剂直接催化CO_2和甲醇合成碳酸二甲酯(DMC)反应活性的影响。结果表明,不同老化温度下制备的KIT-6均保持其独特的三维孔道结构。随着老化温度升高,KIT-6比表面积先增大后减小,当老化温度为100℃时,KIT-6比表面积达到最大(683 m~2·g~(-1))。KIT-6较高的比表面积有利于提高CeO_2分散度,进而提高暴露的活性位点数量,催化活性随催化剂表面中等碱/酸性吸附位数量和Ce~(3+)含量的增加而逐渐提高。其中,CeO_2/100-KIT-6催化剂中CeO_2颗粒尺寸最小(5.9 nm),暴露的活性位数量最高,催化活性最佳。随后,考察了反应温度和压力对CeO_2/100-KIT-6催化活性的影响。随着反应温度提高,催化活性先升高后降低,当反应温度为140℃时,催化活性最高;且催化活性随反应压力的提高而逐渐增加。在反应温度为140℃、压力为6.8 MPa条件下,催化剂经6次循环后,DMC收率由15 mmol·g_(CeO_2)~(-1)逐渐降低至2.8 mmol·g_(CeO_2)~(-1),原因归结为反应过程中CeO_2纳米颗粒发生团聚,使暴露出的活性位数量减少。     

ZrCdOx/SAPO-18双功能催化剂催化CO2加氢合成低碳烯烃性能

采用并流共沉淀法制备了不同Zr/Cd原子比(n_Zr/n_Cd)的ZrCdO_x金属氧化物,并与水热法制备的不同硅铝比(n_{SiO_(2})/n_{Al_(2}O₃))的片状SAPO-18分子筛物理混合制得ZrCdO_x/SAPO-18双功能催化剂,研究了其催化CO₂加氢直接合成低碳烯烃性能。采用透射电子显微镜(TEM)、X射线衍射(XRD)、N2吸附-脱附、CO₂程序升温脱附(CO₂-TPD)、NH3程序升温脱附(NH3-TPD)和X射线光电子能谱(XPS)对催化剂进行了分析。与单一ZrO2相比,引入CdO使得ZrCdO_x比表面积下降,当n_Zr/n_Cd=8时制备的Zr8Cd1氧化物呈现出无定形小颗粒状,Zr与Cd之间较强的协同作用使得Zr Cd Ox氧化物产生了更多的氧空位,有利于CO₂的吸附活化。通过对Zr8Cd1金属氧化物与SAPO-18(硅铝比0.1)的质量比、工艺反应温度、压力和空速对催化性能影响的考察,获得了最佳反应条件。研究还发现,当SAPO-18的硅铝比从0.1降为0.01时,Br?nsted酸含量降低,产物中烯烃/烷烃物质的量之比从18.6提高至37.2,但副产物CO含量迅速增加,低碳烯烃时空收率明显下降。     

1，1'-二羟基-5，5'-联四唑的镧系金属配合物的合成、表征及热行为

以1,1′-二羟基-5,5′-联四唑(H_2BTO)为配体,镧系金属离子作为金属中心,采用溶剂热法制备了5种金属配合物:[La_2(BTO)_3(H_2O)_8]·2H_2O (1)、[Ce_2(BTO)_3(H_2O)_8]·2H_2O (2)、[Pr_2(BTO)_3(H_2O)_8]·2H_2O (3)、[Sm_2(BTO)_3(H_2O)_8]·2H_2O (4)和[Nd_2(BTO)_3(DMF)_4]·6H_2O (5)。通过单晶X射线衍射和元素分析对5种配合物的结构进行了表征。结果表明,5种配合物均属于单斜晶系,P2_1/n空间群。利用差示扫描量热法研究了配合物1～4的热稳定性,采用Kissinger法和Ozawa法分别计算了其热分解动力学参数。     

Catalytic Asymmetric Mannich‐Type Reaction Enabled by Efficient Dienolization of α,β‐Unsaturated Pyrazoleamides†

(E)‐α,β‐Unsaturated pyrazoleamides undergo facile dienolization to furnish copper(I)‐(1Z,3Z)‐dienolates as the major in the presence of a copper(I)‐(R)‐DTBM‐SEGPHOS catalyst and Et₃N, which react with aldimines to afford syn‐vinylogous products as the major diastereoisomers in high regio‐ and enantioselectivities. In some cases, the diastereoselectivity is low, possibly due to the low ratio of copper(I)‐(1Z,3Z)‐dienolates to copper(I)‐(1Z,3E)‐dienolates. (Z)‐Allylcopper(I) species is proposed as effective intermediates, which may form an equilibrium with copper(I)‐(1Z,3Z)‐dienolates. Interestingly, the present methodology is a nice complement to our previous report, in which (E)‐β,γ‐unsaturated pyrazoleamides were employed as the prenucleophiles in the copper(I)‐catalyzed asymmetric vinylogous Mannich‐Type reaction and anti‐vinylogous products were obtained. In the previous reaction, copper(I)‐ (1Z,3E)‐dienolates were generated through α‐deprotonation, which might form an equilibrium with (E)‐allylcopper(I) species. Therefore, it is realized in the presence of a copper(I) catalyst that (E)‐α,β‐unsaturated pyrazoleamides lead to syn‐products and (E)‐β,γ‐unsaturated pyrazoleamides lead to anti‐products. Finally, by use of (E)‐β,γ‐unsaturated pyrazoleamide, (E)‐α,β‐unsaturated pyrazoleamide, (R)‐DTBM‐SEGPHOS, and (S)‐DTBM‐SEGPHOS, the stereodivergent synthesis of all four stereoisomers is successfully carried out. Then by following a three‐step reaction sequence, all four stereoisomers of N‐Boc‐2‐Ph‐3‐Me‐piperidine are synthesized in good yields, which potentially serve as common structure units in pharmaceutically active compounds.     

基于氧化还原体系纸芯片法对血清尿酸含量的快速检测

建立了以纸芯片为分析平台的尿酸含量快速检测方法.基于尿酸的还原性,以FeCl3为氧化剂组成氧化还原体系,以邻二氮菲为显色剂对反应产物Fe2+进行显色,根据显色强度对尿酸含量进行测定.结果 表明,当FeCl3与尿酸比例为1.6∶1,反应10 min,显色剂pH 7.4时显色最佳.显色强度(RGB值)与尿酸浓度在1.19～5.95 mmol/L范围内呈良好线性关系,相关系数为0.9998.方法 的检测限为0.342 mol/L,日内和日间相对标准偏差分别为0.42％和0.47％.15种共存物质在允许误差范围内均无干扰.测得牛血清中尿酸含量为0.238 mmol/L,平均回收率为96.4％.该方法可用于血清中尿酸含量检测.     

SnO2表面卤化提高钙钛矿太阳能电池光伏性能

钙钛矿太阳能电池(PSCs)成为近几年来迅速发展的新型太阳能电池,其中将SnO₂纳米粒子层用作电子传输层(ETL)的钙钛矿太阳能电池器件得到了广泛的关注。SnO₂有着更低的制备温度,使其具备应用于柔性器件的潜力,但与钙钛矿层能级不匹配等问题限制着其发展。而在界面处加入钝化层,尤其是表面卤化的方法或可解决这一问题。本文综合研究了SnO₂表面卤化对钙钛矿太阳能电池光伏性能的影响,选用四丁基氯化铵(TBAC)、四丁基溴化铵(TBAB)和四丁基碘化铵(TBAI)三种钝化材料对SnO₂表面进行钝化处理,并对钝化材料溶液进行了浓度梯度研究。通过材料形貌、结构和光学性能表征以及电池器件性能测试分析等方法,证明了SnO₂表面卤化可提高钙钛矿层的质量和PSCs光伏性能,并从器件内部电荷传输动力学等角度解释了器件性能改善的原因。为进一步说明其性能改善的机理,采用基于密度泛函理论(DFT)的第一性原理计算方法对材料表面性质进行了深入研究,从能量、结构、电荷密度、态密度、功函数等角度解释了表面卤化提高SnO₂/钙钛矿界面处电子传输特性的原因。实验和理论计算均表明TBAC对于SnO₂具有较好的钝化效果,并随着溶液浓度的提升钝化作用越明显。SnO₂表面卤化作用的深入研究不仅对提高电池器件性能具有实际意义,还能够帮助理解太阳能电池界面现象,为界面改性提供新的研究思路。     

An interlocked coordination cage based on aromatic amide ligands

An interlocked M_4 L_8 coordination cage was synthesized by coordination-driven self-assembly of palladium(Ⅱ) ions with aromatic amide bidentate ligands.The reaction of the ligand and the metal at 2:1 ratio led to the monomeric M_2 L_4 cage as the kinetic product,while the thermodynamic product M_4 L_8 cage was obtained by prolongating the reaction.This conve rsion and the interlocked structure was clearly revealed by using ~1 H NMR,mass spectrometry and X-ray crystallography.The driving force of interlocking was mainly attributed to the interactions(hydrogen bonding,aromatic stacking and electrostatic interaction) arising from the aptitude of flexibility of the amide ligand.     

A purely organic D-π-A-π-D emitter with thermally activated delayed fluorescence and room temperature phosphorescence for near-white OLED

A purely organic D-π-A-π-D type emitter showing thermally activated delayed fluorescence(TADF) and room temperature phosphorescence(RTP) was designed and synthesized by utilizing the benzophenone as an acceptor and the N-phenyl-2-napthylamine as a donor moiety.It exhibits considerable TADF character in doped PMMA film and room temperature phosphorescence with a long lifetime of 74 ms at466 nm in solid state.The devices with the configuration of ITO/Mo_2 O_3(4 nm)/mCP(30 nm)/mCP:x wt%NP2 BP/TmTyPB(60 nm)/LiF(1.5 nm)/AI(100 nm) were prepared by vacuum evaporation to explore their electroluminescent performance.Intere stingly,the non-doped device has obtained near-white emission with a fluorescence emission peak at 475 nm and a phosphore scence emission peak at 563 nm having the CIE coordinate of(0.23,0.32) and the maximum external quantum efficiency of 1.09%.