Ultrathin 2D Coordination Polymer Nanosheets by Surfactant-Mediated Synthesis

Graphene related magnetic materials: micromechanical exfoliation of 2D layered magnets based on bimetallic anilate complexes with inserted [FeIII(acac2-trien)]+ and [FeIII(sal2-trien)]+ molecules

The syntheses, structures and magnetic properties of the coordination compounds of formula [FeIII(acac2-trien)][MnIICrIII(Cl2 An)3]·(CH3CN)2 (1), [FeIII(acac2-trien)][MnIICrIII(Br2An)3]·(CH3CN)2 (2) and [GaIII(acac2-trien)][MnIICrIII(Br2An)3]·(CH3CN)2 (3) are reported. They exhibit a 2D anionic network formed by Mn(ii) and Cr(iii) ions linked through anilate ligands, while the [FeIII(acac2-trien)]+ or [GaIII(acac2-trien)]+ charge-compensating cations are placed inside the hexagonal channels of the 2D network, instead of being inserted in the interlamellar spacing. Thus, these crystals are formed by hybrid layers assembled through van der Waals interactions. The magnetic properties indicate that these compounds behave as magnets exhibiting a long-range ferrimagnetic ordering at ca. 11 K, while the inserted Fe(iii) cations remain in the high-spin state. As for graphene, these layered materials can be exfoliated in atomically-thin layers with heights down to 2 nm by using the well-known Scotch tape method. Hence, this micromechanical procedure provides a suitable way to isolate ultrathin layers of this kind of graphene related magnetic materials. Interestingly, this method can also be successfully used to exfoliate the 2D anilate-based compound [FeIII(sal2-trien)][MnIICrIII(Cl2An)3]·solv (4), which exhibits the typical alternated cation/anion layered structure. This result shows that the micromechanical exfoliation method, which has been extensively used for exfoliating van der Waals layered solids, can also be useful for exfoliating layered coordination compounds, even when they are formed by ionic components.

Structuring of metal-organic frameworks at the mesoscopic/macroscopic scale

The assembly of metal ions with organic ligands through the formation of coordination bonds gives crystalline framework materials, known as metal-organic frameworks (MOFs), which recently emerged as a new class of porous materials. Besides the structural designability of MOFs at the molecular length scale, the researchers in this field very recently made important advances in creating more complex architectures at the mesoscopic/macroscopic scale, in which MOF nanocrystals are used as building units to construct higher-order superstructures. The structuring of MOFs in such a hierarchical order certainly opens a new opportunity to improve the material performance via design of the physical form rather than altering the chemical component. This review highlights these superstructures and their applications by categorizing them into four dimensionalities, zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) superstructures. Because the key issue for structuring of MOFs is to spatially control the nucleation process in desired locations, this review conceptually categorizes the available synthetic methodologies from the viewpoint of the reaction system.

Two-dimensional soft nanomaterials: a fascinating world of materials

The discovery of graphene has triggered great interest in two-dimensional (2D) nanomaterials for scientists in chemistry, physics, materials science, and related areas. In the family of newly developed 2D nanostructured materials, 2D soft nanomaterials, including graphene, Bx Cy Nz nanosheets, 2D polymers, covalent organic frameworks (COFs), and 2D supramolecular organic nanostructures, possess great advantages in light-weight, structural control and flexibility, diversity of fabrication approaches, and so on. These merits offer 2D soft nanomaterials a wide range of potential applications, such as in optoelectronics, membranes, energy storage and conversion, catalysis, sensing, biotechnology, etc. This review article provides an overview of the development of 2D soft nanomaterials, with special highlights on the basic concepts, molecular design principles, and primary synthesis approaches in the context.

Surfactant-directed syntheses of mesostructured zinc imidazolates: formation mechanism and structural insights

A detailed study on the formation mechanism, local and long-range structures of surfactant-directed lamellar zinc imidazolates is presented.

A single precursor approach for ZIF synthesis: transformation of a new 1D [Zn(Im)(HIm)2(OAc)] structure to 3D Zn(Im)2 frameworks

We successfully use a 1-dimensional (1D) chain structure with the formula [Zn(Im)(HIm)₂(OAc)] (Im = imidazolate, HIm = imidazole, OAc = carboxylate) as a single precursor/source of a metal and ligand to directly prepare 3-dimensional (3D) [Zn(Im)₂] frameworks.

Solvent-starved conditions in confinement cause chemical oscillations excited by passage of a cathodic delamination front

In situand operando Raman spectroscopy shows oscillations in pH during delamination of a polymer coating.

Solvent induced rapid modulation of micro/nano structures of metal carboxylates coordination polymers: mechanism and morphology dependent magnetism

Rational modulation of morphology is very important for functional coordination polymers (CPs) micro/nanostructures, and new strategies are still desired to achieve this challenging target. Herein, organic solvents have been established as the capping agents for rapid modulating the growth of metal-carboxylates CPs in organic solvent/water mixtures at ambient conditions. Co-3,5-pyridinedicarboxylate (pydc) CPs was studied here as the example. During the reaction, the organic solvents exhibited three types of modulation effect: anisotropic growth, anisotropic growth/formation of new crystalline phase and the formation of new crystalline phase solely, which was due to the variation of their binding ability with metal cations. The following study revealed that the binding ability was critically affected by their functional groups and molecular size. Moreover, their modulation effect could be finely tuned by changing volume ratios of solvent mixtures. Furthermore, they could be applied for modulating other metal-carboxylates CPs: Co-1,3,5-benzenetricarboxylic (BTC), Zn-pydc and Eu-pydc etc. Additionally, the as-prepared Co-pydc CPs showed a fascinating morphology-dependent antiferromagnetic behavior.

Supramolecular templating of hierarchically porous metal–organic frameworks

This tutorial review summarises recent advances in the soft templating of metal–organic frameworks with hierarchical porosity across the micro- and mesoporous regimes.

Hybrid surfactant systems with inorganic constituents

Surfactants are molecules of enormous scientific and technological importance, which are widely used as detergents, emulsifiers, and for the preparation of diverse nanostructures. Their fascinating ability to form self-organized structures, such as micelles or liquid crystals, originate from their amphiphilic architecture-a polar head group linked to a hydrophobic chain. While almost all known surfactants are organic, a new family of surfactants is now emerging, which combines amphiphilic properties with the advanced functionality of transition-metal building blocks, for example, redox or catalytic activity and magnetism. These hybrid surfactants exhibit novel self-organization features because of the unique size and electronic properties of the metal-containing entities.