Synthesis of crystalline chalcogenide arsenates in surfactants via a low temperature route

The synthesis of novel materials drives forward the engine that is material science. The discovery of new materials is important not just from the standpoint of new applications, but is also important for the study of the fundamental forces that guide the reaction mechanism. Ever since Flanigen et. al. first reported the synthesis of zeolite like open framework in 1982, this field has grown exponentially. Nearly 25 elements of the periodic table have open framework structures attributed to them. Metal – chalcogenides have been a very important part of this Solid State chemistry. They have a wide range of applications like ion conductivity, magnetism and non – linear optical response. The larger size of chalcogen atoms allows them to have larger coordination numbers, thus increasing the number of ways they can form open frameworks. This offers a very good opportunity to study the area of open frameworks from different reactions. Solvent thermal synthesis has garnered much attention lately for its ability to produce diverse open framework topologies. By varying the reaction media and the structure directing agent, the desired properties expected of the final product can be finely tuned. Recently, using Ionic Liquids as reaction media, a number of new chalcogenide open frameworks have been reported. The high cost and limited commercial availability of Ionic Liquids has been a great obstacle to the exploitation of their properties as reaction media. Surfactants have long been used to influence the structure of open frameworks. In this investigation, surfactants are used as reaction media, in place of Ionic Liquids. The advantages of this approach is the cheaper costs of the surfactants and their vast varieties available, like acidic, basic, neutral, ionic, etc. This offers great scope for many different interactions between the reagents and the surfactants to form novel open frameworks. In this report, a series of chalcogenidoarsenates is used to demonstrate the excellent qualities of using Surfactants as reaction media. A homologous series of chalcogenidoarsenates is synthesised with dimensionalities varying from 0D clusters to 3D framework. The crystals exhibit semi conductor behaviour, with band gaps of 1.91eV to 2.46eV, which corresponds to the colour of the crystals. The crystals also exhibit magnetic properties, which are tested. Thus, this method offers new possibilities in the field of open framework syntheses of crystalline materials with diverse range of structures and properties.MASTER OF ENGINEERING (MSE

Regioisomeric donor-acceptor-donor triads based on benzodithiophene and BODIPY with distinct optical properties and mobilities

Two regioisomeric triads D-A1-D and D-A2-D composed of benzodithiophene donors and BODIPY acceptors were synthesized and exhibited spectral coverage up to 700 nm due to efficient intramolecular charge transfer. Structural differences and planarity of these triads lead to distinct photoinduced electron transfer characteristics and charge carrier mobilities of up to similar to 10(-4) cm(2) V-1 s(-1)

Growing Crystalline Chalcogenidoarsenates in Surfactants: From Zero-Dimensional Cluster to Three-Dimensional Framework

Although surfactants have been widely used to tailor the size, shape, and surface properties of nanocrystals and control the pore size and phases of mesoporous frameworks, the use of surfactants as reaction media to grow chalcogenide crystals is unprecedented. In addition, compared with ionic liquids, surfactants are much cheaper and can have multifunctional properties such as acidic, basic, neutral, cationic, anionic, or even block. These features suggest that surfactants could be promising reaction platforms for the development of novel chalcogenide crystals. In this work, we used chalcogenidoarsenates as a model system to demonstrate our strategy. By using three different surfactants as reaction media, we obtained a series of novel thioarsenates ranging from a zero-dimensional (0D) cluster to a three-dimensional (3D) framework, namely, [NH₄]₈[Mn₂As₄S₁₆] (<b>1</b>), [Mn­(NH₃)₆]­[Mn₂As₂S₈(N₂H₄)₂] (<b>2</b>), [enH]­[Cu₃As₂S₅] (<b>3</b>), and [NH₄]­[MnAs₃S₆] (<b>4).</b> The band gaps (estimated from the steep absorption edges) were found to be 2.31 eV for <b>1</b> (0D), 2.46 eV for <b>2</b> (1D), 1.91 eV for <b>3</b> (2D), and 2.08 eV for <b>4</b> (3D). The magnetic study of <b>4</b> indicated weak antiferromagnetic behavior. Our strategy of growing crystalline materials in surfactants could offer exciting opportunities for preparing novel crystalline materials with diverse structures and interesting properties