基于多金属氧簇的手性超分子液晶

以手性诱导为切入点,采用含胆固醇基团的季铵盐表面活性剂静电包覆缺位的Keggin结构多金属氧簇K₇PW₁₁O₃₉·12H₂O,得到了手性介晶阳离子修饰的多金属氧簇杂化超分子复合物。圆二色谱对该复合物光学活性的表征说明外围的手性表面活性剂可以通过静电相互作用诱导复合物显示出手性。利用差示扫描量热曲线法、偏光显微镜观察和变温X射线衍射详细研究了该复合物的热性质和相行为,结果表明该复合物在较宽的温度范围内具有热致液晶性质,是一种典型的手性近晶A相离子液晶材料。     

基于铕取代多金属氧簇的手性发光液晶材料（英文）

将铕取代的多金属氧簇引入手性液晶体系是构筑多功能手性发光软材料的有力工具。圆二色谱表明手性两亲分子可以通过静电相互作用诱导非手性多金属氧簇显示出超分子手性。差示扫描量热法、偏光显微镜和变温X射线衍射证实这种有机无机杂化的多金属氧簇复合物具有热致液晶性质。复合物的薄膜显示出本征发光,并且我们可以通过温度调控复合物的发光性质。用手性介晶阳离子静电包覆多金属氧簇是构筑多金属氧簇基手性发光液晶材料的有效方法。     

枝杈状Bola型两亲分子包覆的层状近晶相多金属氧簇液晶

我们利用离子自组装的方法以含苯甲酸基团的两亲分子A6包覆了含铕的无机多金属氧簇Na9[EuW10O36]。利用红外光谱、热重分析、元素分析等方法对所得有机无机杂化复合物A6Eu进行了详细的结构表征。苯甲酸基团通过分子间氢键相互作用发生的二聚使有机组分形成了枝杈状的Bola型结构,这种结构导致外围的介晶基元以侧向方式连接在无机簇上。我们通过差示扫描量热法、偏光显微镜和变温X射线衍射对A6Eu的热致液晶性质进行了表征。虽然单独的两亲分子A6组装成了简单的近晶结构,但是复合物A6Eu表现出新颖的层状近晶相液晶结构。层状近晶相液晶结构中介晶基元是平行于层面的。由此可见,介晶基元的侧向连接方式对复合物的热致组装结构具有重要影响。多金属氧簇的荧光性质在液晶材料中得到了很好的保持。     

枝杈状Bola型两亲分子包覆的层状近晶相多金属氧簇液晶（英文）

我们利用离子自组装的方法以含苯甲酸基团的两亲分子A6包覆了含铕的无机多金属氧簇Na_9[EuW_(10)O_(36)]。利用红外光谱、热重分析、元素分析等方法对所得有机无机杂化复合物A6Eu进行了详细的结构表征。苯甲酸基团通过分子间氢键相互作用发生的二聚使有机组分形成了枝杈状的Bola型结构,这种结构导致外围的介晶基元以侧向方式连接在无机簇上。我们通过差示扫描量热法、偏光显微镜和变温X射线衍射对A6Eu的热致液晶性质进行了表征。虽然单独的两亲分子A6组装成了简单的近晶结构,但是复合物A6Eu表现出新颖的层状近晶相液晶结构。层状近晶相液晶结构中介晶基元是平行于层面的。由此可见,介晶基元的侧向连接方式对复合物的热致组装结构具有重要影响。多金属氧簇的荧光性质在液晶材料中得到了很好的保持。     

含磷钼酸的超分子复合材料的制备和结构研究

介绍了一类端基含羧基结构的液晶性表面活性剂CDDA通过静电相互作用与磷钼酸(HPMo)进行复合,得到表面包覆柔性烷基链和羧基端基的复合物SEP-PMo,并通过元素分析、热失重等方法确认其化学结构.该复合物表现出稳定的液晶相,DSC,PLM,SAXS和TEM等研究表明其为层状相结构.进一步将SEP-PMo复合物与P4VP混合,通过羧基与吡啶环上氮的氢键相互作用,得到稳定的PMo和聚合物的复合物,同时对比研究了HPMo与P4VP直接共混后的静电复合物结构,表明经表面活性剂修饰后的PMo可在聚合物中保持其聚集态结构.     

氧化还原对Lindqvist型多金属氧簇复合物自组装的动态调控（英文）

自组装的动态调控对材料科学的发展至关重要,它在智能材料和器件的开发中具有巨大的潜力。多金属氧簇是一类纳米尺度的无机功能簇,尤其是当它被有机组分共价修饰或者非共价修饰之后,已经发展成为超分子自组装中优异的构筑基元之一。多金属氧簇是典型的刺激响应功能团簇,光化学或电化学方法可将其还原为混合价态,即使经历了逐步的多电子氧化还原后多金属氧簇的结构仍保持不变。多金属氧簇独特的光致变色使其表现出不同的光物理性质,这激励着我们去开发基于多金属氧簇复合物的动态自组装。Lindqvist型六钼酸盐簇[Mo_6O_(19)]~(2-)是负电荷数目最少的多金属氧簇之一,是构筑新颖组装结构的理想构筑基元。本文在乙腈溶剂中用十八烷基三甲基铵替换Lindqvist型多金属氧簇复合物(TBA)_2[Mo_6O_(19)]的抗衡离子,通过简单的替换方法制备了一种单链表面活性剂包覆的多金属氧簇复合物(ODTA)_2[Mo_6O_(19)]。通过核磁共振氢谱、红外光谱、热重分析和元素分析表征了多金属氧簇复合物的结构。复合物(ODTA)_2[Mo_6O_(19)]在乙腈和异丙醇(体积比是4比1)中的溶液在经过交替的紫外光照和空气氧化后表现出了可逆的光致变色性质。复合物的溶液经紫外光照后由浅黄色快速变成蓝色。紫外可见吸收光谱在751 nm处出现的宽吸收带归属于MoV→MoVI的价间电荷转移跃迁,这表明还原态多金属氧簇的形成。经过空气氧化之后蓝色褪去。这种可逆的光致变色可以多次循环实现。扫描电镜、透射电镜和X射线衍射的测试证实了复合物在乙腈和异丙醇中形成了螺旋形貌的组装体。更有意义的是,复合物在光致变色的同时发生了从螺旋条带到球形组装体的形貌转变。光致变色过程中的形貌演变是从短螺旋条带经过海胆型聚集体变为球形组装体。最重要的是,经过空气氧化后螺旋组装体可以再次恢复,表明这是由氧化还原刺激驱动的可逆形貌转变。X射线光电子能谱和核磁共振氢谱的测试表明,氧化还原调控的可逆自组装是由无机簇与有机阳离子之间静电吸引力和无机簇之间静电排斥力的变化所驱动的。此研究结果将有助于更好地理解动态自组装的机理,并有助于推动先进智能材料的精准制备。     

SDS/CTAB/H2O体系特异性质研究

对SDS/CTAB/H2O系统的三元相行为,导电能力,粘度性质等进行了相关性研究,发现相图中存在两个规则的液晶区。当SDS/CTAB(摩尔比)接近1∶2或2∶1时,其混合水溶液中表面活性剂分子异种电荷间的静电引力作用和同种电荷间的静电斥力作用达到吻合状态,既不易形成以胶束为主的均相溶液体系,也不易形成沉淀,而是形成远程有序组合体-液晶结构。当表面活性剂总浓度一定时,具有液晶结构的SDS/CTAB混合水溶液体系,致使体系的导电能力及粘度均呈现极大值。     

多金属氧簇-聚合物复合物磁共振成像及光热-化学治疗性质

通过将阳离子型聚合物聚二烯丙基二甲基氯化铵、嵌段共聚物聚(甲基丙烯酸(聚乙二醇单甲醚)酯-b-甲基丙烯酸)和含Gd的多金属氧簇K7(Gd(H2O)3P2W17O61)以及部分还原的K_6(α-P_2W_(18)O_(62))共混,构建了纳米尺寸的聚合物包埋多金属氧簇的多组分复合物PDDA-PPBM-rPOMs.实验表明,所制备的复合物在水溶液、磷酸盐缓冲液和细胞培养基溶液中都具有较好的结构稳定性,形成均一分散的直径约为67 nm的球形组装体.磁性金属氧簇的存在和较大的粒子半径使复合物在0.5 T磁场条件下的纵向弛豫效率达到51.32 L?mmol~(-1)?s~(-1),并且在载药之后没有明显降低.复合物中部分还原的多金属氧簇中的不同价态金属离子之间存在的电荷转移使复合物在载药前后均表现出良好的光热转换能力,其中,载药后的复合物在808 nm激光(1.0 W?cm~(-2))下持续照射10 min可以产生20℃的温度增量,为其用于肿瘤光热治疗提供了可能. PDDA-PPBM-rPOMs内部静电交联结构为其负载抗肿瘤药物阿霉素提供了合适的场所,使其具有超过90%的载药率,并且pH=5.0下的累积释药量是pH=7.4下的3倍,表现出明显的pH响应性药物释放能力.细胞毒性和流式细胞凋亡实验表明载药的复合物在激光照射下可以有效地抑制肿瘤细胞生长,实现光热治疗与化学治疗的协同,这也为多金属氧簇多功能复合材料用于肿瘤诊断和治疗一体化的发展提供了可用思路.     

新型手性液晶单体、交联剂及其弹性体的合成与表征

报道了一种含薄荷基的手性单体(MLC)、液晶交联剂(CA)及胆甾弹性体(LCE),采用FT-IR与1 H-NMR等手段表征了它们的化学结构,液晶的热性能与光学织构采用DSC、TGA、POM等仪器进行测试研究。结果表明:单体MLC呈现手性近晶C相的破碎扇形织构及胆甾相的油丝织构和焦锥织构,交联剂CA在升降温过程中均呈现典型的近晶A相的扇形织构和向列相的线状织构,而弹性体LCE呈现胆甾相的Grandjean彩色织构,为互变热致液晶聚合物,此外,轻度的化学交联并没有显著影响弹性体的液晶性质,其对应的玻璃化温度和清亮点分别是10.5℃和176.2℃。TGA表明液晶弹性体具有良好的热稳定性,热分解温度为339℃。     

具有氟烷基边链和手性中心液晶化合物的合成及液晶性研究

本文设计合成了十个含氟烷基边链和手性中心的液晶化合物，并通过DSC和偏光显微镜对它们的液晶性进行了研究。其中二环系液晶化合物不显示液晶相或仅显示单边近晶A相。三环系液晶化合物中较长的氟烷基边链有利于近晶相的形成，且当液晶核另一端的烷氧基链的长度适中时，在氟烷基边链和液晶核之间具有手性中心的液晶分子显示了手性近晶C相和其它液晶相。     

Frontispiece: Controlled Self-assembly of Gold(I) Complexes by Multiple Kinetic Aggregation States with Nonlinear Optical and Waveguide Properties

Introduction of multiple kinetic aggregation states (Aggs) into the self-assembly pathway could bring complexity and flexibility to the self-assemblies, which is difficult to realize due to the delicate equilibria established among different Aggs bonded by weak noncovalent interactions. Here, we describe a series of chiral and achiral d¹⁰ Au^I bis(N-heterocyclic carbene, NHC) complexes, and the achiral complex could undergo self-assembly with multiple kinetic Aggs. Generation of multiple kinetic Aggs was realized by applying chiral or achiral seeds exhibiting large differences in elongation temperatures for their respective cooperative self-assembly processes. We further showed that the chiral Au^I self-assemblies having non-centrosymmetric packing forms exhibit nonlinear optical response of second harmonic generation (SHG), while the SHG signal is absent in the achiral analogue. The crystalline achiral Au^I self-assemblies could function as optical waveguides with strong emission polarization.     

A High‐Temperature Molecular Ferroelectric Zn/Dy Complex Exhibiting Single‐Ion‐Magnet Behavior and Lanthanide Luminescence

Multifunctional molecular ferroelectrics are exciting materials synthesized using molecular chemistry concepts, which may combine a spontaneous electrical polarization, switched upon applying an electric field, with another physical property. A high‐temperature ferroelectric material is presented that is based on a chiral Zn²⁺/Dy³⁺ complex exhibiting Dy³⁺ luminescence, optical activity, and magnetism. We investigate the correlations between the electric polarization and the crystal structure as well as between the low‐temperature magnetic slow relaxation and the optical properties.     

新型双烯丙基化手性二胺的合成

通过烯丙基溴化锌对手性亚胺的两次不对称加成, 合成了光活性的双烯丙基化的新型手性二胺. 首先经N-Boc保护和Dess-Martin氧化制得了光活性的(S)-N-Boc-3-苯基-2-氨基丙醛. (S)-N-Boc-3-苯基-2-氨基丙醛与(S)-缬氨基酸甲酯缩合生成手性亚胺, 在七水合三氯化铈(CeC1₃•7H₂O)催化以及底物的手性诱导作用下, 该手性亚胺与烯丙基溴化锌经不对称加成反应合成了高光活性的单烯丙基化手性胺. 该手性胺与2-噻吩甲醛缩合生成新的手性亚胺, 再次通过不对称烯丙基加成反应合成了含有四个手性中心的高光学纯的双烯丙基化手性二胺. 目标化合物和关键中间体的结构均被¹H NMR, ¹³C NMR及MS确证.     

Structurally Precise Silver Sulfide Nanoclusters Protected by Rhodium(III) Octahedra with Aminothiolates

A 60‐nuclear silver sulfide nanocluster with a highly positive charge ( 1 ) has been synthesized by mixing an octahedral Rh^III complex with 2‐aminoethanethiolate ligands, silver(I) nitrate, and d ‐penicillamine in water under mild conditions. The spherical surface of 1 is protected by the chiral octahedral Rh^III complex, with cleavage of the C?S bond of the d ‐penicillamine supplying the sulfide ions. Although 1 does not contain d ‐penicillamine, it is optically active because of the enantiomeric excess of the Rh^III molecules induced by chiral transfer from d ‐penicillamine. 1 can accommodate/release external Ag⁺ ions and replace inner Ag⁺ ions by Cu⁺ ions. The study demonstrates that a thiolato metal complex and sulfur‐containing amino acid can be used as cluster‐surface‐protecting and sulfide‐supplying regents, respectively, for creating chiral, water‐soluble, structurally precise silver sulfide nanoclusters, the properties of which are tunable through the addition/removal/exchange of Ag⁺ ions.     

Dipyrrin‐Bis(N‐Confused Porphyrin) Conjugate: Synthesis,Synergetic Ligation and Chirality Sensing

A fully conjugated system 4 consisting of two 2‐aza‐21‐carbaporphyrin (NCP) subunits bridged by dipyrrin was synthesized by a highly selective condensation of 3‐pyrrole‐NCP 2 with aryl aldehydes. The free base 4 as well as its silver(III) complex 5 exhibited flexibility of the bridge allowing synergetic binding of Ag^I, thus leading to a mixed‐valence tetraporphyrinic assembly consisting of eight silver atoms which was characterized both in the solid state and in solution. Binding of chiral acid by 4 and 5 was shown by observation of an induced optical activity of the adducts.     

Enantioselective synthesis of endohedral metallofullerenes

Endohedral metallofullerenes are promising materials in biomedical and material sciences. In particular, they are of interest as agents for magnetic resonance imaging (MRI), photovoltaic devices, and semimetallic components. The synthesis of chiral endofullerenes represents one step further in the potential use of these carbon allotropes; however, this step has not been addressed so far. In this regard, enantiopure endofullerenes are expected to open new avenues in fields in which chirality is a key issue. Here, the synthesis and characterization of the first chiral endohedral metallofullerenes, namely, chiral bis-adducts of La@C(72), are reported. Eight optically active isomers were obtained by enantioselective 1,3-dipolar cycloaddition of a N-metalated azomethine ylide onto a non-isolated-pentagon rule metallofullerene derivative, La@C(72)(C(6)H(3)Cl(2)), catalyzed by a copper chiral complex. The chiral bis-adducts of La@C(72), isolated by nonchiral HPLC, showed optical purities as high as 98% as revealed by the remarkable positive or negative Cotton effects observed in the circular dichroic spectra.     

Synthesis and optical activity of isosorbide chiral derivative containing fluorocarbon group as chiral dopant in liquid crystal materials

Novel isosorbide derivative containing perfluorocarbon group,bi（perfluorooctanesulfonyl）isosorbide ester as chiral dopant in liquid crystal,was synthesized.Chemical structure was characterized by elemental analysis,FT-IR,¹H NMR and ¹⁹F NMR.The optical texture of the mixture was observed by polarized optical microscopy（POM）.Novel chiral dopant containing perfluorocarbon group had excellent optical activity.Its specific rotation and molar rotation were noticeable higher than those of bi（4-chloromethylbenzenecarbonic）isosorbide ester.The fluorocarbon group improved the molar rotation of chiral compound and did not affect optical rotation direction.The texture of the mixture added isosorbide derivative with fluorocarbon group showed the oily streak texture.     

Comparison of the Electronic and Vibrational Optical Activity of a Europium(III) Complex

The geometry and the electronic structure of chiral lanthanide(III) complexes are traditionally probed by electronic methods, such as circularly polarised luminescence (CPL) and electronic circular dichroism (ECD) spectroscopy. The vibrational phenomena are much weaker. In the present study, however, significant enhancements of vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectral intensities were observed during the formation of a chiral bipyridine–Eu^III complex. The ten‐fold enhancement of the vibrational absorption and VCD intensities was explained by a charge‐transfer process and the dominant effect of the nitrate ion on the spectra. A much larger enhancement of the ROA and Raman intensities and a hundred‐fold increase of the circular intensity difference (CID) ratio were explained by the resonance of the λ=532 nm laser light with the ⁷F₀ → ⁵D₀ transitions. This phenomenon is combined with a chirality transfer, and mixing of the Raman and luminescence effects involving low‐energy ⁷F states of europium. The results thus indicate that the vibrational optical activity (VOA) may be a very sensitive tool for chirality detection and probing of the electronic structure of Eu^III and other coordination compounds.     

Optical manipulation with nanoscale chiral fields and related photochemical phenomena

Chiral light-matter interaction occurs when the system consists of the matter and the light has a chiral structure, which is generically called the chiro-optical effect. Circular dichroism and optical rotation are representative spectroscopic methods based on chiro-optical effects. Chiro-optical effects have been widely utilized to detect chiral materials in the system. The chiro-optical effect also has the potential to create chiral materials from achiral materials and chiral optical fields, and to generate chiral optical fields from chiral matter systems. To achieve that, the design and observation of chiral optical field structures are essential. In this article, we describe local chiral optical fields generated in the peripheries of nanomaterials (typically metal nanostructures) irradiated with light. We summarize basic characteristics of nanoscale local chiral optical fields, methods to observe/control the chiral optical field structures at nanomaterials. Then some chemical, optical, and mechanical effects of designed chiral optical fields are described. Chiral nanostructures were created from achiral nanomaterials combined with circularly polarized light. Nucleation of chiral crystals of achiral molecules was achieved by circularly polarized light with the aid of plasmonic materials. Circularly polarized luminescence was observed from achiral fluorescent molecules conjugated with chiral plasmonic nanostructures. On mechanical characteristics, optical forces exerted on chiral materials were found to be dependent on the handedness of incident circularly polarized light, which can be utilized to discriminate the chirality of the material. The concept can be further generalized to the spin-dependent asymmetric light-matter interactions, which will create not only the molecular- and nano-scale chiral structures but also various novel functions of materials that are correlated with the handedness degree of freedom.