Electrochemical synthesis of gold nanocrystals and their 1D and 2D organization

Size-controlled gold nanocrystals were conveniently synthesized through direct electroreduction of bulk AuCl(4)(-) ions in the presence of poly(N-vinylpyrrolidone) (PVP). PVP greatly enhanced the gold particle formation process and also significantly retarded the gold electrodeposition process, allowing the electrochemical synthesis of gold nanocrystals to be carried out in the form of simple electroreduction. This novel electrochemical method may be extended to synthesis of other noble metal nanoparticles with controllable size on a large scale. The PVPK90-protected gold nanocrystals spontaneously self-assembled into nearly ordered 2D close-packed arrays and interesting 1D nanostructures. The aggregation of unstable PVPK17-protected gold nanocrystals resulted in the formation of ultrathin single-crystalline films. PVP plays multifunctional roles in controlling the size and shape of gold nanocrystals and in inducing individual gold nanocrystals to construct 1D nanostructures. The nanoparticle self-assembling technique based on PVP offers a simple, but effective, path to organize individual gold nanoparticles into various 1D and 2D nanostructured materials.     

Organic Nonlinear Optical Materials: The Mechanism of Intermolecular Covalent Bonding Interactions of Kekulé Hydrocarbons with Significant Singlet Biradical Character

The ground‐ and excited‐state properties of benzene‐linked bisphenalenyl (B‐LBP), naphthaline‐linked bisphenalenyl (N‐LBP), and anthracene‐linked bisphenalenyl (A‐LBP) Kekulé molecules and their respective one‐dimensional (1D) stacks are investigated using time‐dependent density functional theory (TD‐DFT) and a range of extensive multidimensional visualization techniques. The results reveal a covalent π–π bonding interaction between overlapping phenalenyl radicals whose bond length is shorter than the van der Waals distance between carbon atoms. Increasing the linker length and/or number of molecules involved in the 1D stack decreases the HOMO–LUMO energy gap and increases the wavelength of the systems. The charge‐transfer mechanism and electron coherence both differ with changes in the linker length and/or number of molecules involved in the 1D stack.     

Construction of Supramolecular Self‐Assembled Microfibers with Fluorescent Properties through a Modified Ionic Self‐Assembly (ISA) Strategy

Highly ordered supramolecular microfibers were constructed through a simple ionic self‐assembly strategy from complexes of the N‐tetradecyl‐N‐methylpyrrolidinium bromide (C₁₄MPB) surface‐active ionic liquid and the small methyl orange (MO) dye molecule, with the aid of patent blue VF sodium salt. By using scanning electron microscopy and polarized optical microscopy, the width of these self‐assembled microfibers is observed to be about 1 to 5 μm and their length is from tens of micrometers to almost a millimeter. The ¹H NMR spectra of the microfibers indicates that the supramolecular complexes are composed of C₁₄MPB and MO in equal molar ratio. The electrostatic, hydrophobic, and π–π stacking interactions are regarded as the main driving forces for the formation of microfibers. Furthermore, through characterization by using confocal fluorescence microscopy, the microfibers were observed to show strong fluorescent properties and may find potential applications in many fields.     

Morphological and mechanical properties of nascent polyethylene fibers produced via ethylene extrusion polymerization with a metallocene catalyst supported on MCM‐41 particles

Polyethylene (PE) fibers were prepared by ethylene extrusion polymerization with an MCM‐41‐supported titanocene catalyst. The morphological and mechanical properties of these nascent PE fibers were investigated. Three levels of fibrous morphologies were identified in the fiber samples through an extensive scanning electron microscopy study. Extended‐chain PE nanofibrils with diameters of about 60 nm were the major morphological units present in the fiber structure. The nanofibrils were parallel‐packed into individual microfibers with diameters of about 1–30 μm. The microfibers were further aggregated irregularly into fiber aggregates and bundles. In comparison with commercial PE fibers and data reported in the literature, the individual microfibers produced in situ via ethylene extrusion polymerization without posttreatment exhibited a high tensile strength (0.3–1.0 GPa), a low tensile modulus (3.0–7.0 GPa), and a high elongation at break (8.5–20%) at 35 °C. The defects in the alignment of the nanofibrils were believed to be the major reason for the low modulus values. It was also found that a slight tensile drawing could increase the microfiber strength and modulus. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2433–2443, 2003     

孔道三维相互连通锐钛矿TiO2-SiO2纳米复合介孔材料的制备及其高光催化活性

本文报道一种孔道三维相互连通锐钛矿TiO2-SiO2纳米复合介孔材料的制备.该介孔材料是以两维六方有序结构、直孔道、锐钛矿70TiO2-30SiO2-950纳米复合介孔材料(于950oC晶化2 h)为前驱体, NaOH为SiO2的刻蚀剂,通过“在孔壁内造孔”的方法获得.我们的策略是采用温和的造孔条件,如稀NaOH溶液,合适的温度与固/液比等.采用X射线衍射(XRD),透射电镜(TEM)和低温N2吸附等技术对样品的介孔结构进行了系统表征.结果表明,墙内孔的密度非常高,孔径均一(平均尺寸3.6 nm),且在三维网络高度连通原孔道,但介孔结构仍保持其完整性.锐钛矿纳米晶粒的结晶度和大小在墙内造孔前后基本保持不变.该材料光催化降解罗丹明B(0.303 min–1)与亚甲基蓝(0.757 min–1)的活性相当高,此活性分别是其母体材料的5.1和5.3倍,甚至是Degussa P25光催化剂的16.5和24.1倍.这充分表明三维连通孔道结构对活性的大幅提高起了关键作用.孔道三维连通式锐钛矿TiO2-SiO2纳米复合介孔材料对上述污染物展现出意想不到的高降解活性,显著高于迄今已报道的金属氧化物基介孔材料对上述污染物的降解活性.更重要的是,该光催化剂具有相当高的稳定性和重复使用性.相信,本方法将为具有超高性能的孔道三维相互连通其它金属氧化物基介孔材料的制备铺平了道路.
　　小角XRD结果表明,母体材料的孔道是两维六方有序结构,在孔壁内造孔之后,样品原有的介孔结构仍保持其规整性.宽角XRD结果显示,二氧化钛的晶相是锐钛矿,晶粒尺寸为10.8 nm.造新孔之后,锐钛矿纳米晶粒的结晶度和大小与母体样品的相比变化不大. TEM结果显示,母体样品的孔壁内没有孔.孔道是两维六方有序排列的直孔道,孔径大小均一(平均尺寸4.1 nm).高分辨透射电镜(TEM)观察揭示,锐钛矿纳米晶粒(平均大小11.3 nm)在孔壁内随机排列,并与无定形SiO2纳米颗粒相互连接,相间共存,形成类似“砖块?水泥砂浆”砌成的孔壁,这种独特的复合骨架结构赋予其很高的稳定性.当一些SiO2纳米颗粒被去除之后, TEM观察显示,孔壁内有密集分布的孔,这些孔取向随机,并在三维方向连通原孔道,但介孔骨架结构仍保持其完整性.墙内孔的大小范围很窄(3.1?4.3 nm),平均大小为3.6 nm.高分辨TEM观察显示,锐钛矿晶粒大小与母体材料内的相比基本未变.上述结果与XRD结果一致.低温N2吸附表征结果显示,母体样品内只有一种孔道,孔径为4.0 nm.去除部分SiO2后的样品内有两种孔道,孔径分别是3.4和4.1 nm.这些结果与TEM的观察吻合.罗丹明B与亚甲基蓝在造孔前后样品内扩散速率评价结果显示,其在三维连通孔道内的扩散速率很高,大约是其母体材料内的5倍以上.这表明相互连通的孔道网络结构非常有利于客体分子在其内扩散.光催化降解性能评价结果显示,罗丹明B与亚甲基蓝在相互连通孔道内降解的速率相当高,分别是其在不连通孔道内的5.1和5.3倍.这充分证明孔道三维相互连通对活性的大幅提高起了关键作用.我们对材料的稳定性和重复使用性作了评价,经过10次循环使用孔道三维相互连通锐钛矿TiO2-SiO2纳米复合介孔材料,其吸附与光催化降解罗丹明B的性能变化不大.这充分证明本文制备的孔道连通复合介孔材料的性能是相当稳定的和可重复使用的.该方法可用于制备具有超高性能的孔道三维相互连通其它金属氧化物基介孔材料,如Nb2O5, Ta2O5等.     

通过稀土离子和羧酸配体组装成的两种新型的二维配位聚合物的合成、晶体结构及荧光性质

利用水热法合成了两种新型的二维（2D）稀土配位聚合物[Ln(PDC)(OH)(H2O)2]n (Ln = Eu (1) and Tb (2), H2PDC = 3,4-吡啶二羧酸),通过元素分析、红外光谱、热分析和X射线单晶衍射等技术对其进行了表征。单晶结构分析表明这两种配合物都显示出包含有一维Ln-O-Ln链的二维层状结构,层间又进一步通过 π-π 堆积和氢键作用扩展成三维超分子网络结构。此外,这两种配合物的固体在室温下都有强的荧光发射。     

Hydrothermal Synthesis and Characterization of Quasi‐1‐D Tungsten Disulfide Nanocrystal

Quasi‐1‐D (one‐dimensional) tungsten disulfide (WS₂) nanocrystal was synthesized through a two‐step hydrothermal process. Energy dispersive spectroscopy (EDS) identified that the chemical composition of the final product was WS₂. The produced nanocrystal was further characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results have shown that most of the products are quasi‐1‐D nanocrystals with the width around 140 nanometers and thickness about 30 nanometers. However, the length of the majority of nanocrystals could reach 1 micron. The selected area electron diffraction (SAED) pattern indicates that the nanocrystal is of a single crystal. N₂ adsorption measurement revealed that the BET specific surface area of this sample is 97 m²g^?1, which indicates that the as‐prepared product has better catalyzing and friction performance.     

Simple Fabrication of Multicomponent Heterogeneous Fibers for Cell Co‐Culture via Microfluidic Spinning

Microfluidic spinning, as a combination of wet spinning and microfluidic technology, has been used to develop microfibers with special structures to facilitate cell 3D culture/co‐culture and microtissue formation in vitro. In this study, a simple microchip‐based microfluidic spinning strategy is presented for the fabrication of multicomponent heterogeneous calcium alginate microfibers. The use of two kinds of microchip enables the one‐step preparation of multicomponent heterogeneous microfibers with various arrangement patterns, including the preparation of one‐, two‐, and three‐component microfibers by a two‐layer microchip and preparation of four component microfibers with different arrangement by a membrane‐sandwiched three‐layer microchip. The obtained microfibers could be used to encapsulate various kinds of cells, such as the human non‐small cell lung cancer cell NCI‐H1650, the human fetal lung fibroblast HFL1, the normal pulmonary bronchial epithelial cell 16HBE, and human umbilical vein endothelial cells. By adding chitosan to the medium to keep the fibers stable, 3D long‐term in vitro cell co‐culture has been carried out up to 21 days. This method is very simple and easy to operate, continuously produces spatially well‐defined heterogeneous microfibers, has important applications for composite functional biomaterials, and shows great potential in organs‐on‐a‐chip and biomimetic systems.     

Supramolecular Structures with the 2‐Propyl‐4,5‐dicarboxy‐1H‐imidazole Ligand: Hydrothermal Synthesis,Structures, and Photoluminescence

Self‐assembly of the rigid organic ligand 2‐propyl‐4,5‐dicarboxy‐1H‐imidazole ( L ) with different metal ions (Zn²⁺, Ni²⁺, Cu²⁺, Cd²⁺) led to four new complexes, namely, [M( L )(phen)] [M = Zn ( 1 ); Ni ( 2 ); Cd ( 3 )] and [Cu( L )( 4 )] (phen = 1,10‐phenanthroline). Their structures were determined by single‐crystal X‐ray diffraction analyses, and they were further characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. Whereas compounds 1 , 2 , and 3 are discrete units, hydrogen‐bonding interactions play a vital role in these complexes. Compounds 1 and 2 form one‐dimensional (1D) and two‐dimensional (2D) structures through hydrogen‐bondinginteractions with helical character. In 1 , the hydrogen bonds (O–H ··· O) alternately bridge the M^II cations of the discrete units to form a one‐dimensional (1D) infinite helical chain. Complex 2 forms a 2D helical layer through parallel hydrogen bonds (N/O–H ··· O/N) between two adjacent helical chains. In 3 , the hydrogen bonds (N–H ··· O) connect adjacent discrete units into a ten‐membered ring with extension into a one‐dimensional double‐chain supramolecular structure. Complex 4 is a two‐dimensional gridlike (4,4) topological layer which is extended to a 3D network by hydrogen bonding. The solid‐state fluorescence spectrum of complex 3 was determined.     

Encapsulation of ZnS:Mn2+ nanocrystals with diblock copolymers

The encapsulation of the nanocrystalline manganese‐doped zinc sulfide (ZnS:Mn) in poly(styrene‐b‐2vinylpyridine) (PS‐PVP) diblock copolymers is reported. Below the critical micelle concentration in the absence of nanocrystals (NCs), inverse micelles of PS‐PVP were induced by adding ZnS:Mn NCs, the presence of which was confirmed by scanning force microscope and dynamic light scattering. In toluene, a PS‐selective solvent, the less‐soluble PVP blocks preferentially surround the ligand‐coated ZnS:Mn NCs. For PS‐PVP encapsulated ZnS:Mn NCs, the ratio of blue emission to orange emission of ZnS:Mn NCs is dependent on both the concentration of PS‐PVP and the solvent quality. The pyridine of PVP blocks form complexes with the Zn atoms via the nitrogen lone pair and thus the sulfur vacancies are passivated. As a result, the defect‐related blue emission is selectively quenched even when the micelles are not formed. As the concentration of PS‐PVP encapsulating the ZnS:Mn NCs increases, the intensity of blue emission decreases. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3227–3233, 2006     

Cooperative Supramolecular Polymerization of Fluorescent Platinum Acetylides for Optical Waveguide Applications

One‐dimensional organic structures with well‐oriented π‐aggregation, strong emission, and ease of processability are desirable for optoelectronic waveguiding devices. Herein, a strategy is developed to attain this objective by self‐assembling platinum(II) acetylides into fluorescent supramolecular polymers via cooperative mechanism. The resulting high‐molecular‐weight supramolecular polymers are capable of forming electrospun microfibers with uniform geometry and smooth surface, which enable light propagation with extremely low scattering loss (0.008 dB μm⁻¹). With the elaborate combination of bottom‐up supramolecular polymerization and top‐down electrospinning techniques, this work offers a novel and versatile avenue toward high‐performance optical waveguiding materials.     

Shape‐controlled synthesis of Pt nanocrystals: an evolution of the tetrahedral shape

Platinum nanocrystals with sizes smaller than 10 nm are obtained by H₂‐reduction of aqueous K₂PtCl₆ in the presence of different concentrations of poly (N‐vinyl‐2‐pyrrolidone; PVP:M_w ≈ 360 000) at pH = 2.5–7.0. Tetrahedral Pt nanocrystals (3–10 nm) are produced with high selectivity (73–83% by number) at moderate PVP:K₂PtCl₆ ratios. The co‐existing round/spheroidal crystallites are found to be smaller than the tetrahedrally shaped ones in the systems of varying K₂PtCl₆:PVP ratios. Careful examinations of the particle size and shape evolution of the crystallites at different stages of the crystal growth with transmission electron microscopy (TEM) and ultraviolet–visible absorption spectroscopy (UV–vis) suggest that the tetradedrally shaped Pt crystallites share the same type of nuclei with the round ones at the early stage of the crystal formation. Evolution of the tetrahedral shape happens in the later slow crystal growth. Copyright © 2006 John Wiley & Sons, Ltd.     

One‐Pot Synthesis of Pomegranate‐Structured Fe3O4/Carbon Nanospheres‐Doped Graphene Aerogel for High‐Rate Lithium Ion Batteries

A unique hierarchically nanostructured composite of iron oxide/carbon (Fe₃O₄/C) nanospheres‐doped three‐dimensional (3D) graphene aerogel has been fabricated by a one‐pot hydrothermal strategy. In this novel nanostructured composite aerogel, uniform Fe₃O₄ nanocrystals (5–10 nm) are individually embedded in carbon nanospheres (ca. 50 nm) forming a pomegranate‐like structure. The carbon matrix suppresses the aggregation of Fe₃O₄ nanocrystals, avoids direct exposure of the encapsulated Fe₃O₄ to the electrolyte, and buffers the volume expansion. Meanwhile, the interconnected 3D graphene aerogel further serves to reinforce the structure of the Fe₃O₄/C nanospheres and enhances the electrical conductivity of the overall electrode. Therefore, the carbon matrix and the interconnected graphene network entrap the Fe₃O₄ nanocrystals such that their electrochemical function is retained even after fracture. This novel hierarchical aerogel structure delivers a long‐term stability of 634 mA h g^?1 over 1000 cycles at a high current density of 6 A g^?1 (7 C), and an excellent rate capability of 413 mA h g^?1 at 10 A g^?1 (11 C), thus exhibiting great potential as an anode composite structure for durable high‐rate lithium‐ion batteries.     

Two‐Dimensional Infrared Spectroscopy Reveals the Structure of an Evans Auxiliary Derivative and Its SnCl4 Lewis Acid Complex

Determining the structure of reactive intermediates is the key to understanding reaction mechanisms. To access these structures, a method combining structural sensitivity and high time resolution is required. Here ultrafast polarization‐dependent two‐dimensional infrared (P2D‐IR) spectroscopy is shown to be an excellent complement to commonly used methods such as one‐dimensional IR and multidimensional NMR spectroscopy for investigating intermediates. P2D‐IR spectroscopy allows structure determination by measuring the angles between vibrational transition dipole moments. The high time resolution makes P2D‐IR spectroscopy an attractive method for structure determination in the presence of fast exchange and for short‐lived intermediates. The ubiquity of vibrations in molecules ensures broad applicability of the method, particularly in cases in which NMR spectroscopy is challenging due to a low density of active nuclei. Here we illustrate the strengths of P2D‐IR by determining the conformation of a Diels–Alder dienophile that carries the Evans auxiliary and its conformational change induced by the complexation with the Lewis acid SnCl₄, which is a catalyst for stereoselective Diels–Alder reactions. We show that P2D‐IR in combination with DFT computations can discriminate between the various conformers of the free dienophile N‐crotonyloxazolidinone that have been debated before, proving antiperiplanar orientation of the carbonyl groups and s‐cis conformation of the crotonyl moiety. P2D‐IR unequivocally identifies the coordination and conformation in the catalyst–substrate complex with SnCl₄, even in the presence of exchange that is fast on the NMR time scale. It resolves a chelate with the carbonyl orientation flipped to synperiplanar and s‐cis crotonyl configuration as the main species. This work sets the stage for future studies of other catalyst–substrate complexes and intermediates using a combination of P2D‐IR spectroscopy and DFT computations.     

Self-organized monolayer of nanosized ceria colloids stabilized by poly(vinylpyrrolidone)

Four nanometer colloidal ceria nanocrystals in a fluorite cubic structure have been synthesized via an alcohothermal treatment at 180 degrees C for 24 h from Ce(NO(3))(3)*6H(2)O in ethanol, using various alkylamines including triethylamine, butylamine, and hexadecylamine as the bases and poly(vinylpyrrolidone) (PVP) as the stabilizer. They were characterized by multiple measurements of X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), ultraviolet visible (UV-vis) spectroscopy, dynamic light scattering (DLS), and infrared spectroscopy (IR). The introduction of PVP could effectively stabilize the cerium nuclei against self-aggregation and finally lead to the formation of the CeO(2) colloids. As compared with that of their precipitated counterparts, the UV-vis spectra showed a blue-shifted absorption edge for the as-obtained colloidal nanocrystals, revealing that their surfaces were well-passivated by PVP. Four types of self-organized monolayer patterns (i.e., isolated particles, short chainlike (pseudo-1-D aggregated), pearl necklace-like (1-D aggregated), and dendritic (pseudo-2-D aggregated) alignments) appeared for the as-obtained colloidal particles on the copper TEM grids, due to the delicate balance of the attractive and repulsive forces between the PVP-passivated CeO(2) nanocrystals during the irreversible evaporation of the solvent from various colloidal solutions under ambient conditions. The type of alkylamine and the concentration of PVP were confirmed to be the crucial factors determining the oriented-aggregation dimensionality of the CeO(2) colloids. Possible interparticle interaction modes have been suggested to explain such complex self-organization patterns exhibited by the as-obtained CeO(2) nanocrystals.     

Growth kinetics of platinum nanocrystals prepared by two different methods: role of the surface

In order to examine the applicability of the diffusion-limited Ostwald ripening model to the growth kinetics of nanocrystals, platinum nanocrystals prepared by two different methods have been investigated by a combined use of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). One of the methods of synthesis involved the reduction of chloroplatinic acid by sodium citrate while in the other method reduction was carried out in the presence of polyvinylpyrrolidone (PVP) as a capping agent. The growth of platinum nanocrystals prepared by citrate reduction in the absence of any capping agent follows a Ostwald ripening growth with a D(3) dependence. In the presence of PVP, the growth of platinum nanocrystals does not completely follow the Ostwald ripening model, making it necessary to include a surface reaction term in the growth equation. Thus, the growth of platinum nanocrystals in the presence of PVP has contributions both from diffusion and surface reaction, exhibiting a D(3)+D(2) type behavior.     

Size Fractionation of Two‐Dimensional Sub‐Nanometer Thin Manganese Dioxide Crystals towards Superior Urea Electrocatalytic Conversion

A universal technique has been proposed to sort two‐dimensional (2D) sub‐nanometer thin crystals (manganese dioxide MnO₂ and molybdenum disulfide MoS₂) according to their lateral dimensions. This technique is based on tuning the zeta potential of their aqueous dispersions which induces the selective sedimentation of large‐sized 2D crystals and leaves the small‐sized counterparts in suspension. The electrocatalytic properties of as‐obtained 2D ultrathin crystals are strongly dependent on their lateral size. As a proof‐of‐concept study, the small‐sized MnO₂ nanocrystals were tested as the electrocatalysts for the urea‐oxidation reaction (UOR), which showed outstanding performance in both half reaction and full electrolytic cell. A mechanism study reveals the enhanced performance is associated with the remarkable structural properties of MnO₂ including ultrathin (ca. 0.95 nm), laterally small‐sized (50–200 nm), and highly exposed active centers.     

Surfactant‐Free Self‐Assembly of Nanocrystals into Ellipsoidal Architectures

A simple approach to control the self‐assembly of ZnS nanocrystals into well‐defined, uniform, three‐dimensional, micrometer‐scale, solid ellipsoidal structures with rattle‐type, multishelled, and hollow architectures is presented. There is no surfactant or small molecule to assist the self‐assembly of the nanocrystals. A possible mechanism of the controlled self‐assembly is proposed. The growth process can be divided into two stages: 1) the formation of ellipsoidal architectures via oriented aggregation, the growth kinetics of which is primarily attributed to the charge–charge, charge–dipole, and dipole–dipole interactions of preformed ZnS nanocrystals; and 2) Ostwald ripening, which results in multishelled, rattle‐type, and hollow structures. This self‐assembly concept is also applicable to other metal sulfides.     

Cadmium(II) Complexes with a Bulky Anthracene‐based Carboxylate Ligand: Syntheses,Crystal Structures,and Luminescent Properties

To explore the coordination possibilities of anthracene‐based ligands, three cadmium(ιι) complexes with anthracene‐9‐carboxylate ( L ) and relevant auxiliary chelating or bridging ligands were synthesized and characterized: Cd₂( L )₄(2bpy)₂(μ‐H₂O) ( 1 ), Cd₂( L )₄(phen)₂(μ‐H₂O) ( 2 ), and {[Cd₃( L )₆(4bpy)]}_∞ ( 3 ) (2bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, and 4bpy = 4,4′‐bipyridine). Structural analyses show that complexes 1 and 2 both take dinuclear structures by incorporating the chelating 2bpy or phen ligand, which are further interlinked by intermolecular hydrogen‐bonding, π ··· π stacking, and/or C–H ··· π supramolecular interactions to generate higher‐dimensional supramolecular frameworks. Complex 3 has a one‐dimensional (1D) ribbon‐like structure, which is further assembled into a two‐dimensional (2D) layer, and a three‐dimensional (3D) framework by the co‐effects of interchain C–H ··· O hydrogen‐bonding and C–H ··· π supramolecular interactions. Moreover, the luminescent properties of these complexes were further investigated in detail.     

Direct Self‐Assembly of a 2D and 3D Star of David

Two‐ and three‐dimensional metallosupramolecules shaped like a Star of David were synthesized by the self‐assembly of a tetratopic pyridyl ligand with a 180° diplatinum(II) motif and Pd^II ions, respectively. In contrast to other strategies, such as template‐directed synthesis and stepwise self‐assembly, this design enables the formation of 2D and 3D structures in one step and high yield. The structures were characterized by both one‐dimensional (¹H, ¹³C, ³¹P) and two‐dimensional (COSY, NOESY, DOSY) NMR spectroscopy, ESI‐MS, ion‐mobility mass spectrometry (IM–MS), AFM, and TEM. The stabilities of the 2D and 3D structures were measured and compared by gradient tandem mass spectrometry (gMS²). The high stability of the 3D Star of David was correlated to its high density of coordination sites (DOCS).