Co~Ⅱ(salen~*)存在下的氯丁二烯自由基聚合

研究了N,N'-双(3,5-二叔丁基水杨醛)-1,2-环己二胺钴(Ⅱ)[Co~Ⅱ(salen~*)]存在下氯丁二烯(CP)的自由基聚合,考察了不同溶剂、引发剂用量及配体对聚合反应的影响.结果表明,随着引发剂用量的增加,聚合反应的诱导期缩短,以[ABVN]0/[Co~Ⅱ(salen~*)]0=3/1配比投料,聚合反应表现出较好的可控聚合特征.在苯、甲苯、四氢呋喃(THF)和乙酸乙酯(EA)4种溶剂中按照[CP]_0/[Co~Ⅱ(salen~*)]0/[ABVN]0=400/1/3的配比投料,在苯中的可控聚合程度最好:在低转化率(40%以下)实测聚合物分子量(Mn,GPC)与理论值(Mn,th)吻合,且分子量随转化率增加呈线性增长.研究了THF、三乙胺(NEt3)、吡啶(Py)及水等不同配体对聚合反应的影响,发现在添加THF时,低转化率(40%以下)下Mn,GPC与Mn,th相符,分子量分布(PDI)相对较窄.     

Molecular Design Tactics for Highly Efficient Thermally Activated Delayed Fluorescence Emitters for Organic Light Emitting Diodes

Recently, pure organic thermally activated delayed fluorescence (TADF) emitters have attracted considerable interest from the scientific community in the field of organic light emitting diodes (OLEDs) as they can theoretically realize 100 % of the internal quantum efficiency by exploiting both the singlet and triplet excitons via the reverse intersystem crossing enabled by small singlet‐triplet energy splitting. Currently, the external quantum efficiency of the TADF emitters is reaching the level of phosphorescent emitters. Therefore, the TADF approach is considered as a potential alternative to the low efficiency conventional fluorescent and expensive phosphorescent emitters. In this account, we summarized our recent development of blue and green TADF molecular designs to improve the device performances of the TADF devices.     

Efficient and highly diastereoselective preparation of a myrtenal derived bis-sulfoxide and its preliminary evaluation as chiral acyl donor

Treatment of disulfide 7 with NaIO₄ in EtOH at rt gave monosulfoxide 8 (95%), while at 50 °C it gave trans-bis-sulfoxide 6a (84%, >99% de). In contrast, treatment of 7 with MCPBA gave bis-sulfone 9 (95%). The anion of 6a reacted with benzaldehyde affording carbinol 10 (76%, >99% de). The absolute configuration of 8, 6a, and 10 was established by single crystal X-ray diffraction analyses.     

献血员血清中20种元素的ICP-MS测定

用电感耦合等离子体质谱（ＩＣＰ－ ＭＳ） 测定献血员血清中２０ 种元素, 采用多元素内标法校正基体效应引起的系统误差, 加入内标元素Ｓｃ 、Ｉｎ 和Ｔｌ 分别校正质量数＜ １００ 、１００ ～１８０ 和＞ １８０ 的元素测定, 用牛血清标样ＧＢＷ ０９１３１ 为质控标准物质, 检验方法的可靠性。 测定了献血组和健康对照组血清中微量元素含量, 进行数理统计, 检验其差异性。     

Kinetics and mechanisms in carbocationic polymerization: The quest for true rate constants

This article is a critical analysis of kinetic dataavailable on carbocationic polymerizations. A survey of published propagation rate constant (k_p) data revealed several orders of magnitude differences. In this article, an explanation of this apparent discrepancy is offered with a case study involving the carbocationic polymerization of 2,4,6‐trimethylstyrene (TMS). With the polymerization mechanism originally proposed for this system, k_p = 1.35 × 10⁴ L mol^?1 s^?1 was extracted from experimental data with the Predici polyreaction package. The alternative mechanism yielded k_p = 1.01 × 10⁷ L mol^?1 s^?1, close to that predicted by Mayr's Linear Free Energy Relationship (LFER). We propose that true rate constants can only be obtained from direct competition experiments or from kinetic interpretation based on independently proven mechanisms. The second part of this review discusses critical analysis of the temperature and concentration dependence of various living IB systems. Comparison of the temperature dependence in systems initiated with 2‐ chloro‐2,4, 4‐ trimethylpentane (TMPCl)/TiCl₄ from various laboratories yielded of ΔH ～?25 and ?34.5 kJ/mol for high and low TMPCl/TiCl₄ ratios, respectively. Aromatic (cumyl‐type) initiators show ΔH ～ ?40 kJ/mol, whereas H₂O/TiCl₄ in the presence of the strong electron‐ pair donor dimethylacetamide gave ΔH = ?12 kJ/mol. The significant differences indicate different underlying mechanisms with complex elementary reactions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5394–5413, 2005     

Nitrogen Donor Protection for Atomically Precise Metal Nanoclusters

Surface organic ligands are critical in dictating the structures and properties of atomically precise metal nanoclusters. In contrast to the conventionally used thiolate, phosphine and alkynyl ligands, nitrogen donor ligands have not been used in the protection for well-defined metal nanoclusters until recently. This review focuses on recent developments in atomically precise metal nanoclusters stabilized by different types of nitrogen donor ligands, in which the synthesis, total structure determination and various properties are covered. We hope that this review will provide insights into the rational design of N donor-protected metal nanoclusters in terms of structural and functional modulation.     

Helicate tris(aryl)carbinolates bearing pendant NR2 donors – a new family of supporting ligands for the synthesis of Sc3+ alkyl complexes

The reactions of aryllithium reagents o-LiC₆H₄CH₂NR₂ with (MeO)₂CO afford two new tris(aryl)carbinols bearing pendant-NR₂ donor groups in the side chain [o-R NCH C H ] COH [R = Me, R + R = (CH) ]. These alcohols feature helical chirality due to differently inclined aromatic fragments and are presented in a crystalline cell as two M and P enantiomers. Carbinol (R = Me) readily reacts with (Me3SiCH2)3Sc(THF)2 to give a scandium bis(alkyl) complex [(o-C₆H₄CH₂NMe₂)₃CO]Sc(CH₂SiMe₃)₂ featuring rigid binding of the alkoxy anion through a κ¹-O, κ²-N chelating coordination mode     

紫色石蕊溶液配制方法的探究

石蕊溶液在碱性溶液中变色不明显,这个问题虽小,但它一直困扰着我们的实验教学活动。利用手机软件颜色识别器、数字传感器等几种软硬件技术手段,对石蕊试剂的选择、配制方法的优化、溶液pH的调节等方面进行探究,试图配制出在酸碱性溶液中显色明显的石蕊溶液。     

Synthesis,Structures, and Fluorescent Properties of Three Cobalt‐Based Coordination Polymers with a Rigid Tripodal Carboxylate Ligand

Three cobalt(II) coordination polymers, [Co₂(tatb)₂(2,2′‐bipy)₂ (H₂O)₂ · DMA · 2H₂O] ( 1 ), [Co₂(tatb)₂(1,10‐phen)₂(H₂O)₂ · 2H₂O] ( 2 ) and [Co(tatb)(1,3‐dpp) · H₂O] ( 3 ) (H₃tatb = 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoic acid; 2,2′‐bipy = 2,2′‐bipyridyl; 1,10‐phen = 1,10‐phenanthroline; 1,3‐dpp = 1,3‐bis(pyridin‐4‐yl)propane), were synthesized solvothermally and characterized by single‐crystal and powder X‐ray diffraction (PXRD), as well as IR spectroscopy. Complexes 1 and 2 exhibit 1D double‐chain structures, which further connect into interesting 3D networks by hydrogen bond and strong π–π interactions. Complex 3 possesses 2D 4⁴‐sql topology, which is packed parallel in an AA fashion. Moreover, thermal stability properties and photoluminescence properties of 1 , 2 and 3 were also investigated.