| dc.description.abstract | The crystalline materials obtain their fundamental physical properties from the molecular arrangement within the solids, and altering the placement and/or interactions between these molecules can usually have a direct impact on the properties of a particular solid. The crystal form diversity drive unique physicochemical properties. Solid form discovery and design depends on the nature of the molecule of interest and the type of physical property challenges faced in its development.
Crystal engineering has evolved in such a manner that it invokes self-assembly of existing molecules to generate a wide range of new solid forms without the need to break or form covalent bonds. The structural features can be regarded as the result of a series of molecular recognition events via specific interactions. Co-crystals have excited the interest of many researchers in the crystal engineering field as a way to tailor-make material properties.
Despite of a large number of literatures about co-crystals, most paper focused mainly on active pharmaceutical ingredients (APIs). The aim of this thesis is to take the full advantage of those current advancements in APIs to creat exotic supramolecular architectures and to concoct a convenient, systematic, efficient, and close-to-scale-up-conditions method for screening, manufacturing, and characterization of co-crystal. Cytosine has been chosen for this study mainly as a co-crystal component with a series of dicarboxylic acids of increasing aliphatic chain length, HOOC(CH2)nCOOH (n= 0 to 2) were selected as co-crystal co-formers. The solvent-drop grinding method was selected to be the co-crystal screening method and solution crystallization was used for co-crystal manufacturing. The molecular recognition among cytosines and the supramolecular heterosynthons of our fabricated co-crystals might be used for the investigation of theoretical sites of cytosine specific to molecular imprint and DNA-binding proteins. Common laboratory analytical tools such as PXRD, DSC, TGA, FT-IR, OM, EA, and SXD were used to understand the supramolecular architectures and to ensure the quality of co-crystals. 4:1 co-crystal of cytosine-oxalic acid dihydrate, 2:1 co-crystal of cytosine-malonic acid, and 2:1 co-crystal of cytosine-succinic acid were manufactured.
Formerly, most of those who study the physical and chemical properties of the co-crystal compound were from the pharmaceutical industry, and thus there was no literature mentioning the optical properties of co-crystals. Therefore, we hope to fabricate co-crystal compounds for optical devices in which the photoluminescence (PL) intensity of the co-crystal compounds having optoelectronic properties could be tuned by varying the kinds of co-crystal co-formers. It could widely be applied in the manufacturing process of organic light-emitting diodes (OLED), or even biologic light-emitting diodes (BioLED).
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