Discovery-based dye chemistry: synthesis and properties of new functional molecules, ligands, and coordination complexes

点击翻译按钮获取中文摘要

Organic dyes and pigments have been used to colour our world (textiles, paints, coatings, etc) for millennia, originally using naturally occurring dyes but now mostly using dyes made synthetically. Coloured molecules can also possess other capabilities such as redox activity, emission, photochemical activity, or the ability to bind to metals. These properties make them useful in a huge range of applications including catalysis solar energy conversion, and health & medicine. A focus of many research groups is to optimize a particular known type of dye for a particular application. This optimization process involves the synthesis of several related derivatives of the dye/complex (typically by changing substituents) and developing structure-property relationships. My group's approach is more fundamental in nature. We aim to design, make, study, and develop new kinds of dyes and metal complexes thereof. We want to make new molecules have properties (e.g. photophysical, redox) that are interesting/innovative/useful. Our long term goals are to broaden the molecular toolkit for other researchers in the application-oriented areas mentioned above. We are particularly interested in molecules that are intense light absorbers at the low end of the visible spectrum and the near-infrared. This spectral region is critical for several fields of research but it is challenging to make new chromophores absorb light here. Part of this proposal focuses on our recent success in converting the famous textile pigment indigo into more soluble diimine analogues. Current/future target areas in this proposal will include (1) further exploration of the redox/optical properties of Nindigo complexes, through the synthesis and characterization of new Nindigo ligand derivatives as well as new metals; (2) reactivity studies of Nindigo complexes as electron and proton reservoirs; and (3) synthetic exploratory work targeting new Nindigo structure types, with a view to uncovering new ways to make near-infrared absorbing molecules and complexes. A second thrust of this proposal identifies new types of dye ligand structures that will bind to metals and possess extremely unusual optical properties, namely absorption of very energy (near infrared) light.  This application proposes several tridentate, pi expanded variants that are constructed from heterocyclic building blocks such as pyrroles, indoles, and carbazoles; the proposed ligand pi systems are designed to lead to exceptionally low energy (near IR) absorption (both as free molecules and bound to metals) while using substituents to maintain stability. The sub-projects in this area will involve organic/heterocyclic synthesis, as well as synthetic coordination chemistry along with the characterization methods listed above.