Crystal Engineering of Isostructural Compounds Applicatons in Solid State 2 plus 2 Cycloaddition Reactions and Beyond

Abstract

This thesis focuses on the application of crystal engineering to achieve isostructurality in newlinemolecular salts and coordination compounds for various applications. Specifically, Zn(II) and newlineCd(II) based metal complexes are systematically explored to understand their isostructural newlinenature and their affinity for solid-state [2+2] cycloaddition reactions. newlineChapter 1 introduces the principles of crystal engineering, emphasizing its application newlineto achieve isostructurality in molecular salts and coordination compounds. It provides an newlineoverview of key concepts and a comprehensive literature review to identify research gaps. The newlinechapter concludes by defining the scope of the thesis, outlining specific objectives, newlinemethodologies, and expected contributions to the field. newlineChapter 2 investigates isostructurality in molecular salts. The crystal structures of salts newlineincorporating 2,6-naphthalene dicarboxylic acid (ndc) and 4-carboxy cinnamic acid (cca) with newline4-aminopyridine (4apy-H) and 2-aminobenzimidazole (2abi-H) reveal isostructurality, newlineattributed to centrosymmetric disorder in cca. Additionally, solid solutions characterized by newlinePXRD demonstrate that fluorescence intensity can be controlled by adjusting the ndc and cca newlineratio without altering the crystal structure or solid-state phase. newlineChapter 3 examines the photochemical reactivity of three binuclear Cd(II) complexes newlineusing p-toluate (p-tol), 4-fluorobenzoate, and 3-fluorobenzoate as carboxylate linkers, with 4 newlinestyrylpyridine (4spy) as the photoreactive linker. These complexes exhibit isostructurality, with newline4spy linkers aligning in head-to-head (HH) and head-to-tail (HT) configurations, adhering to newlineSchmidt s criteria. During photoirradiation, only HH photoreactions were observed, which was newlinevalidated both quantitatively and via single-crystal XRD analysis. This was further validated newlinethrough the recrystallization of the photoproduct, distinguishing the observed 0D to 0D photo newlinetransformation from typical photo-polymerization in metal complexes. newline(Full uploaded)