Metal-Based Multihelicenic Architectures

The preparation of multihelicenic systems by conventional organic synthesis is a challenging task and under continuous development. In parallel, using complexing units grafted to or incorporated within the helicene core and taking advantage of coordination/organometallic chemistry constitutes a powerful strategy to obtain multihelicenic structures. This Minireview focuses on the state-of-the-art preparation of metal-based multihelicenic architectures such as coordination-driven supramolecular assemblies and organometallic architectures. Their properties and their applications are presented.     

Recent developments in the supramolecular chemistry of terpyridine-metal complexes

This critical review describes recent developments in the field of supramolecular chemistry of terpyridine-metal complexes. The synthesis and characteristics of single as well as multiple homo- and heterometallic complexes is discussed. Furthermore, complexes containing fullerenes, biological building blocks, extended aggregates of different architectures as well as rings are presented. A special emphasis is placed upon the properties (e.g. redox properties, luminescence etc.) of functional systems. Potential applications in optical nano-devices, molecular storage units, molecular switches and solar cells are discussed.     

Synthesis and morphogenesis of organic polymer materials with hierarchical structures in biominerals

Synthesis and morphogenesis of polypyrrole (PPy) with hierarchical structures from nanoscopic to macroscopic scales have been achieved by using hierarchically organized architectures of biominerals. We adopted biominerals, such as a sea urchin spine and nacreous layer, having hierarchical architectures based on mesocrystals as model materials used for synthesis of an organic polymer. A sea urchin spine led to the formation of PPy macroscopic sponge structures consisting of nanosheets less than 100 nm in thickness with the mosaic interior of the nanoparticles. The morphologies of the resultant PPy hierarchical architectures can be tuned by the structural modification of the original biomineral with chemical and thermal treatments. In another case, a nacreous layer provided PPy porous nanosheets consisting of the nanoparticles. Conductive pathways were formed in these PPy hierarchical architectures. The nanoscale interspaces in the mesocrystal structures of biominerals are used for introduction and polymerization of the monomers, leading to the formation of hierarchically organized polymer architectures. These results show that functional organic materials with complex and nanoscale morphologies can be synthesized by using hierarchically organized architectures as observed in biominerals.     

From nonfunctional lamellae to functional nanotubes

[structure: see text] Long chain alkyl-alkyl interactions appears to be the main driving force in hydrogen bond isomerism induced transformation of lamellar architectures to nanotubular constructs in alkylammonium dicarboxylate salts; the syntheses of the nanotubes require no skill for typical organic synthesis, and they are functional materials displaying intriguing gelling properties.     

Recent progress in controlled radical polymerization of N-vinyl monomers

This review summarizes recent advances in the controlled radical polymerization of N-vinyl monomers, such as N-vinylcarbazole, N-vinylindole derivatives, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylformamide, N-vinylacetoamide derivatives, N-vinyl(na)phthalimides, N-vinylimidazolium salts, and N-vinyltriazoles. Recent significant progress of controlled radical polymerization of these N-vinyl monomers has allowed for the synthesis of well-defined functional polymers having various architectures, including block copolymers, branched polymers (stars, star block copolymers, miktoarm star copolymers, and graft copolymers), and hybrids. Characteristic properties, assembled structures, and three-dimensional architectures of these functional polymers derived from N-vinyl monomers are briefly introduced.     

A Preorganized Hydrogen-Bonding Motif for the Molecular Recognition of Carbohydrates

The choice between adaptive and preorganized architectures, or of the most effective hydrogen bonding groups to be selected, are dilemmas that supramolecular chemists must address in designing synthetic receptors for such a challenging guest as carbohydrates. In this paper, structurally related architectures featuring two alternative hydrogen bonding motifs were compared to ascertain the structural and functional origin of their binding differences and the advantages that can be expected in monosaccharide recognition. A set of structurally related macrocyclic receptors were prepared, and their binding properties were measured by NMR and ITC techniques in chloroform vs a common saccharidic target, namely, the β-octyl glycoside of D-glucose. Results showed that the diaminocarbazolic motif, recently reported as the constituting unit of highly effective receptors for saccharides in water, is a superior hydrogen bonding motif compared to the previously described diaminopyrrolic motif, which was successfully employed in molecular recognition of carbohydrates in polar organic solvents, due to intrinsic structural and functional factors, rather than to hydrophobic contributions. In addition, the occurrence of a rare example of a thermodynamic template effect exerted by the beta-glucoside has been ascertained, enhancing the synthesis outcome of the otherwise low yielding preparation of the described macrocyclic receptors.     

Tailor–made Covalent Organic‐Inorganic Polyoxometalate Hybrids: Versatile Platforms for the Elaboration of Functional Molecular Architectures

Post‐functionalization of organically modified polyoxometalates (POMs) is a powerful synthetic tool to devise functional building blocks for the rational elaboration of POM‐based molecular materials. In this personal account we focus on iodoaryl‐terminated POM platforms, describe reliable routes to the synthesis of covalent organic‐inorganic POM‐based hybrids and their integration into advanced molecular architectures or multi‐scale assemblies as well as their immobilization onto surfaces. Valorisation of the remarkable redox properties of POMs in the fields of artificial synthesis and molecular electronic is especially considered.     

Fabrication of copper hydroxyphosphate with complex architectures

Copper hydroxyphosphate [Cu(2)(OH)PO(4)] with complex architectures has been synthesized through a simple and mild hydrothermal route in the absence of any external inorganic additives or organic structure-directing templates. Powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectrometry are used to characterize various properties of the obtained samples. Single-crystals, twinned-crystals, and various novel architectures of copper hydroxyphosphate can be constructed through a careful control of synthetic parameters, such as the molar ratio of initial reagents, reagent concentration, reaction time, and temperature. On the basis of structure and chemical bond analysis, copper hydroxyphosphate crystals tend to grow along the c-axis and have a rotation twinned-crystal growth habit, which is essential for the formation of various complex architectures. The current approach provides a facile strategy to synthesize copper hydroxyphosphate crystals with unique morphologies and complex architectures, which may be applicable to the synthesis of other inorganic materials.     

From linear side-chain functionalized poly(vinyl ether)s to functional macrocycles

This paper deals with the synthesis of functional polymers of controlled chain dimensions and architecture from poly(chloroalky1 vinyl ether)s. The living polymerization of chloroalkyl vinyl ethers initiated by HX/ZnX₂ systems, and the chemical substitution of the pendant chlorines by various organic functions and groups, in order to generate specific polymer properties are first discussed. Also based on the living character of the polymerizations, the preparation of poly(chloroethyl vinyl ether) with monomacrocyclic and plurimacrocyclic architectures as well as their characterization are then reported. Some evidence for specific host–guest interactions between large organic molecules and polymacrocycles is also presented.     

Soluble Hetero-Polyoxovanadates and Their Solution Chemistry Analyzed by Electrospray Ionization Mass Spectrometry

Polyoxometalates (POMs) are an intriguing class of compounds due to their tremendous structural variety and the wide spectrum of resulting properties, which make them interesting for applications in fields such as catalysis, material science or nanotechnology. Their ability to form large supramolecular architectures by self-assembly offers an entry to complex, functional systems. After an introduction into the structure and synthesis of POMs of the early transition metals, recently discovered water-soluble antimonato polyoxovanadates (Sb-POVs) and the investigation of their chemical reactivity are discussed. Electrospray ionization mass spectrometry (ESI-MS) is presented as an analytical technique suitable to investigate the structure of complex POM assemblies in solution and to probe the underlying reactivity and formation mechanisms. This Minireview highlights the first studies on the soluble Sb-POVs and how the knowledge of their reactivity obtained by ESI-MS has fostered the syntheses of numerous novel Sb-POV compounds.     

含吡啶基金属-超分子聚合物研究进展

金属-超分子聚合物是由金属离子与配体之间的相互作用形成的,是一类具有多样化几何构造和拓扑结构的新型功能高分子,它包括线型、接枝、交联、树枝等多种骨架结构.金属-超分子聚合物具有光、电、磁等特性,因此潜在的应用前景非常广阔,不仅可以在生物医用、分子器件、纳米材料,还可以在催化化学反应及吸附储氢等领域获得应用.由于吡啶基团为常用配体,且近年含吡啶基团的金属-超分子聚合物研究最为广泛,最为代表性,因此,本文以聚合物结构分类对近几年含吡啶基团的金属-超分子聚合物的研究进展作了简要综述.     

Assembly of one dimensional inorganic nanostructures into functional 2D and 3D architectures. Synthesis, arrangement and functionality

This review will focus on the synthesis, arrangement, structural assembly, for current and future applications, of 1D nanomaterials (tubes, wires, rods) in 2D and 3D ordered arrangements. The ability to synthesize and arrange one dimensional nanomaterials into ordered 2D or 3D micro or macro sized structures is of utmost importance in developing new devices and applications of these materials. Micro and macro sized architectures based on such 1D nanomaterials (e.g. tubes, wires, rods) provide a platform to integrate nanostructures at a larger and thus manageable scale into high performance electronic devices like field effect transistors, as chemo- and biosensors, catalysts, or in energy material applications. Carbon based, metal oxide and metal based 1D arranged materials as well as hybrid or composite 1D materials of the latter provide a broad materials platform, offering a perspective for new entries into fascinating structures and future applications of such assembled architectures. These architectures allow bridging the gap between 1D nanostructures and the micro and macro world and are the basis for an assembly of 1D materials into higher hierarchy domains. This critical review is intended to provide an interesting starting point to view the current state of the art and show perspectives for future developments in this field. The emphasis is on selected nanomaterials and the possibilities for building three dimensional arrays starting from one dimensional building blocks. Carbon nanotubes, metal oxide nanotubes and nanowires (e.g. ZnO, TiO(2), V(2)O(5), Cu(2)O, NiO, Fe(2)O(3)), silicon and germanium nanowires, and group III-V or II-VI based 1D semiconductor nanostructures like GaS and GaN, pure metals as well as 1D hybrid materials and their higher organized architectures (foremost in 3D) will be focussed. These materials have been the most intensively studied within the last 5-10 years with respect to nano-micro integration aspects and their functional and application oriented properties. The critical review should be interesting for a broader scientific community (chemists, physicists, material scientists) interested in synthetic and functional material aspects of 1D materials as well as their integration into next higher organized architectures.     

Multi-functional,Low Symmetry Pd2L4 Nanocage Libraries**

Although many impressive metallo-supramolecular architectures have been reported, they tend towards high symmetry structures and avoid extraneous functionality to ensure high fidelity in the self-assembly process. This minimalist approach, however, limits the range of accessible structures and thus their potential applications. Herein is described the synthesis of a family of ditopic ligands wherein the ligand scaffolds are both low symmetry and incorporate exohedral functional moieties. Key to this design is the use of Cu^I-catalysed azide-alkyne cycloaddition (CuAAC) chemistry, as the triazole is capable of acting as both a coordinating heterocycle and a tether between the ligand framework and functional unit simultaneously. A common precursor was used to generate ligands with various functionalities, allowing control of electronic properties whilst maintaining the core structure of the resultant cis-Pd₂L₄ nanocage assemblies. The isostructural nature of the scaffold frameworks enabled formation of combinatorial libraries from the self-assembly of ligand mixtures, generating a statistical mixture of multi-functional, low symmetry architectures.     

Two-dimensional electronic conjugation: statics and dynamics at structural domains beyond molecular wires

Chemical architectures supporting a high degree of electronic conjugation serve as important functional components in devices and materials for advanced electronic and photonic applications. Increasing the spatial dimensionality of such constructs can fundamentally modify their optoelectronic properties and significantly alter intra- and intermolecular interactions that are crucial for understanding and controlling charge/energy-transfer processes. In this article, emerging design principles in the construction of well-defined conjugated platforms beyond molecular wires are highlighted. Both covalent and noncovalent approaches can be strategically employed to position one-dimensional (1D) substructures in a spatially well-defined manner in order to enhance both structural and functional complexity in a two-dimensional (2D) setting. A predictable and controllable switching mechanism can be designed and implemented with mobile 2D electronic conjugation that operates by correlated motions of inherently rigid 1D subunits. This emerging "dynamic" approach complements and challenges the prevailing "static" paradigm of conjugated chemical architectures.     

Synthesis and Characterization of a Pentiptycene‐Derived Dual Oligoparaphenylene Nanohoop

Structural designs combining oligoparaphenylene‐derived nanohoops with other functional organic building blocks should lead to novel molecular architectures with intriguing properties. Herein, we describe the synthesis of a pentiptycene‐derived chiral dual nanohoop molecule with key steps including ring expansion through dianthracene cycloreversion and transannular [4+2] cycloaddition across a 64‐membered macrocycle. The crystal structure of the nanohoop molecule displays an ordered packing pattern with long‐range channels in the solid state. Furthermore, nonracemizable enantiomers of the nanohoop were obtained through resolution and exhibited promising chiroptical properties.     

New-generation biomedical materials:Peptide dendrimers and their application in biomedicine

Peptide dendrimers are attractive synthetic polymers and have been widely used as a new generation of biomaterials in recent years.Peptide dendrimers,as well as general dendrimers,may be synthesized to reach nano sizes,and display well-defined architectures,highly-branched structures,high density of functional terminal groups,and controllable molecular weights.On the other hand,peptide dendrimers have properties similar to proteins and some special characteristics,such as good biocompatibility,water solubil...     

新型生物医用材料: 肽类树枝状大分子及其生物医学应用

肽类树枝状大分子是近年来发展起来的一类新型生物医用高分子材料, 它在具有普通树枝状大分子的特征如规整性、高度支化、表面呈现高密度功能团、尺度为纳米级、通过可控制备可得到单一分子量等之外, 同时还具有类似蛋白一样的球状结构、好的生物相容性、水溶性、耐蛋白酶水解、生物降解等独特的性能. 肽类树枝状大分子的上述特点, 使其在生物医学应用中显示出诱人的前景. 本综述从肽类树枝状大分子的制备出发、详尽介绍了肽类树枝状大分子的功能化及其在疾病诊断和治疗中的应用等方面的研究进展, 籍此推动肽类树枝状大分子在生物医学领域的研究与开发.     

金属纳米材料中的晶格应变及其在催化中的应用

纳米结构中的晶格应变作为基础研究课题的势头日益增强.可以设计纳米颗粒的表面晶格以产生应变或者其他结构变化,使其原子位置偏离正常的晶格点,进而影响纳米颗粒的电子结构和催化性能.本文首先介绍了金属纳米粒子的不同应变源,重点介绍了不同应变基本结构的合成.讨论了晶格应变的表征手段及其在催化领域应用的研究进展.最后介绍了应变金属...     

Mechanochemical Synthesis of Stimuli Responsive Microgels

Mechanochemical approaches are widely used for the efficient, solvent-free synthesis of organic molecules, however their applicability to the synthesis of functional polymers has remained underexplored. Herein, we demonstrate for the first time that mechanochemically triggered free-radical polymerization allows solvent- and initiator-free syntheses of structurally and morphologically well-defined complex functional macromolecular architectures, namely stimuliresponsive microgels. The developed mechanochemical polymerization approach is applicable to a variety of monomers and allows synthesizing microgels with tunable chemical structure, variable size, controlled number of crosslinks and reactive functional end-groups.     

Controlled synthesis, growth mechanism and highly efficient solar photocatalysis of nitrogen-doped bismuth subcarbonate hierarchical nanosheets architectures

The synthesis and self-assembly of hierarchical architectures from nanoscale building blocks with unique morphology, orientation and dimension have opened up new opportunities to enhance their functional performances and remain a great challenge. This work represents tunable synthesis of various types of 3D monodisperse in situ N-doped (BiO)(2)CO(3) hierarchical architectures composed of 2D single-crystal nanosheets with dominant (001) facets by a one-pot template-free hydrothermal method from bismuth citrate and ammonia solution. Depending on the concentration of ammonia solution, the morphology of N-doped (BiO)(2)CO(3), including dandelion-like, hydrangea-like and peony flower-like microspheres, can be selectively constructed due to different self-assembly patterns of nanosheets. It was revealed that the ammonia played dual roles in the formation of N-doped (BiO)(2)CO(3) architectures. One is to hydrolyze bismuth citrate, and the other is to behave as a nitrogen doping source. The in situ doped nitrogen substituted for oxygen in (BiO)(2)CO(3) and subsequently narrowed the band gap, making N-doped (BiO)(2)CO(3) visible light active. Due to the special nanosheets architectures, the prepared various N-doped (BiO)(2)CO(3) materials exhibited especially efficient photocatalytic activity and high durability for the removal of NO in air under both visible and UV light irradiation. Based on the direct observation of the growth process with respect to phase structure, chemical composition and morphological structure, a novel growth mechanism is revealed, which involves a unique multistep pathway, including reaction-nucleation, aggregation, crystallization, dissolution-recrystallization, and Ostwald ripening. The facile synthesis approach and the proposed growth mechanism could provide new insights into the design and controlled synthesis of inorganic hierarchical materials with new or enhanced properties.