Functional and Modular As=C and P=C Group Motifs

Sammanfattning: This work focuses on the design, synthesis, characterization, and application projections of low-coordinated heavy pnictogen-containing (described by the generic letter E, hence E=C) phosphaalkenes (P=C) and arsaalkenes (As=C), with emphasis on the E=C group motifs. The work aims to understand their functional and modular character, reactivity, and potential applications by stabilizing, isolating, and characterizing these species in low-coordination environments. The thesis defines a set of elementary principles that allowed the author to better understand the materials from the perspective of "functional materials", with a subset of the compounds categorized as "smart materials" after exploring and elucidating their fascinating responses in a series of experiments using electrochemical and spectroscopic techniques. The thesis successfully explains the role of the As=C and P=C units and their innate role as "directors" of the molecular electronic structure of the compounds based on their relevant actions and interactions, which led to their naming as "group motifs". By focusing on fluorene-based and DBU-based phosphaalkene systems, the research projects extend these two families of compounds. It characterizes their responses to different functional groups, environmental conditions, and constraints as settings. The work illustrates the ability of hydrogen bonding to regulate or stabilize the reactivity of the P=C sites, showing the synthesis of hydrogen-bonded adducts that are more stabilized while maintaining the intrinsic compound identity with the P=C moieties. In addition, a fascinating copper(I)-phosphaalkene complex exhibiting photoluminescence and ambipolar properties is studied. The excited state lifetimes of the compound were measured to be in the nanosecond range, which is of interest for applications. Overall, this work represents a comprehensive study of the chemistry of heavy p-block elements and their potential as materials. This work sheds light on their modularity, reactivity, and potential use as "functional materials" and "smart materials" for a variety of future applications ranging from organic electronics and catalysis to artificial intelligence