The potential of the molecular-building-block (MBB) approach for the assembly and development of functional solid-state porous materials has already been recognized. [1] This approach offers a prospective avenue toward the design and construction of novel materials; that is, desired properties can be incorporated at the design stage. These properties are required to address the myriad technological challenges that face us, including hydrogen storage for fuel applications. In metal-ligand directed assembly, the MBB approach has been adopted for the synthesis of functional metal-organic assemblies (MOAs), which range from discrete (metal-organic polyhedra) to 3D (metal-organic frameworks (MOFs)). Accordingly, various applications, including nonlinear optics (NLO), magnetism, catalysis, and gas storage, were revealed for MOFs. [2,3] These MOFs have proven exceptional owing to their facile tunability (alteration in pore size and functionality), a feature dependent on the rigidity, modularity, and control of the MBBs. Therefore, prior to the assembly process, it is essential that the MBBs possess certain attributes for the construction of targeted structures: each must be rigid, impart the desired directionality, and possess the necessary shape and geometry for that structure.Organic chemistry would seem to offer a vast repertoire to be employed as MBBs, because organic molecules can be designed to contain these features. Nevertheless, organicmolecule-based MBBs with high connectivity are not common, and their assembly into crystalline porous organic frameworks remains a challenge.[4] As such, alternative routes have been pursued combining organic MBBs and inorganic MBBs derived from metal-ligand coordination. Unlike organic MBBs, which are selected already possessing the desired features, typically inorganic MBBs are formed in situ. As a result, reaction conditions to generate a specific inorganic MBB consistently in situ are vital; once established, desired MOAs can be designed and (potentially) assembled by judicious choice of organic ligands. It is clear that continuous development and isolation of novel MBBs will eventually facilitate the rational construction of targeted functional MOAs, an example of design versus serendipity.Strategies based on the MBB approach have already shown promise toward the design and construction of MOAs, and, accordingly, some basic guidelines have been derived: [1] 1) It is essential that the desired inorganic building blocks can be targeted. 2) The organic linker must have specific functionalities that give rise to the desired shape, geometry, and rigidity upon coordination. 3) Reaction conditions must introduce the ability to generate crystalline materials, a result that is vital for structural analysis and correlations between structure and building units. 4) It is accepted that the assembly of simple building blocks, in the absence of any altering agent such as a template or structure directing agent (SDA), will lead to the construction of the default structure relative to...

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It has now been almost thirty years since Wells catalogued network structures in crystals [1] in a manner that has facilitated the crystal engineering [2] of a wide range of infinite 2D and 3D nets. That crystal engineered nets invoke geometric design principles means that a chemically diverse range of molecular building blocks (MBBs) are available for study as exemplified by coordination polymers (i.e. metalorganic networks), [3] polymers sustained by organometallic linkages [4] and hydrogen-bonded organic networks.[5] Coordination polymers are particularly attractive targets for study: metal coordination and cluster geometries are diverse but they are controllable in a manner that facilitates the design of nets with predictable topology and dimensions; metal moieties can be pre-selected so as to impart functional properties, such as magnetism, [6] luminescence [7] or, in the case of openframework nets, permanent porosity; [3c,e, 8] multifunctional organic ligands can also be selected for their geometric attributes. Coordination polymers can be rationalized and designed using the "node-and-spacer" approach, [3a,b] which simplifies molecular building blocks into topological points and lines. Aesthetically pleasing and potentially functional coordination polymers that have been isolated

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We present the synthesis and characterization of p-tert-butylcalix[4]arene-crown ethers (compounds 2 ± 4) with different length of the polyethylenoxy bridge between the distal phenolic OH groups. The studied compounds show selectivity for sodium, potassium or cesium ions. The correlation was made between the stereochemical structure of the ligands and potentiometrically determined ion-selectivity and complex formation constants. The crystal and molecular structure of the p-tert-butylcalix[4]arene-crown-5 complex with potassium iodide have been determined by single crystal X-ray diffraction study.

Background: The development of organic/inorganic metal halide perovskites has seen unprecedent growth since their first recognition for applications in optoelectronic devices. However, their thermodynamic stability and toxicity remains a challenge considering wide-scale deployment in the future. This spurred an interest in search of perovskite-inspired materials which are expected to retain the advantageous material characteristics of halide perovskites, but with high thermodynamic stability and composed of earth-abundant and low toxicity elements. ABX3 chalcogenides (A, B=metals, X=Se, S) have been identified as potential class of materials meeting the aforementioned criteria. Methods: In this work, we focus on studying tin zirconium selenide (SnZrSe3) relevant physical properties with an aim to evaluate its prospects for application in optoelectronics. SnZrSe3 powder and monocrystals were synthesized via solid state reaction in 600 – 750 °C temperature range. Crystalline structure was determined using single crystal and powder X-ray diffraction methods. The bandgap was estimated from diffused reflectance measurements on powder samples and electrical properties of crystals were analysed from temperature dependent I-V measurements. Results: We found that SnZrSe3 crystals have a needle-like structure (space group – Pnma) with following unit cell parameters: a=9.5862(4) Å, b=3.84427(10) Å, c=14.3959(5) Å. The origin of the low symmetry crystalline structure was associated with stereochemical active electron lone pair of Sn cation. Estimated bandgap was around 1.15 eV which was higher than measured previously and predicted theoretically. Additionally, it was found that resistivity and conductivity type depended on the compound chemical composition. Conclusions: Absorption edge in the infrared region and bipolar dopability makes SnZrSe3 an interesting material candidate for application in earth-abundant and non-toxic single/multi-junction solar cells or other infrared based optoelectronic devices.

Eight Cu(II) coordination compounds with cyclic triimidazole, triimidazo[1,2-a:1’,2’-c:1”,2”-e][1,3,5]-triazine (L1), its positional isomer, triimidazo[1,2-a:1’,2’-c:1”,5”-e][1,3,5]-triazine (L2), and two pyridine derivatives of L1, 3-(pyridin-2-yl)triimidazo[1,2-a:1',2'-c:1'',2''-e][1,3,5]triazine (L3) and 3-(pyridin-4-yl)triimidazo[1,2-a:1',2'-c:1'',2''-e][1,3,5]triazine (L4) are reported. All compounds represent...