Pyrroles, (aza)Dipyrrins and their Complexes: Synthesis and Properties

Modern synthetic chemistry involves the design and preparation of molecular constructs with properties that match, or are predicted to match, desired functions such as catalytic activity, bioactivity, optical properties, electrochemical performance, solubility and reactivity. Trainees contributing to the Thompson Discovery Grant research program at Dalhousie University will devise synthetic methodologies for (oligo)pyrrole preparation and functionalization, generating frameworks with rich (photo)physical properties. This research involves harnessing the five-membered nitrogen-containing aromatic pyrrolic unit, a motif used to spectacular effect by nature (e.g. in heme and chlorophyll) yet extremely challenging for chemists to manipulate courtesy of its electron-rich core and notoriously high reactivity. This research provides training in synthetic chemistry, plus the determination and application of properties exhibited by chemical species. Trainees will develop competencies in synthetic sequence design, anhydrous reaction techniques, purification strategies and a broad range of compound characterization methods. These competencies are key to the growing bio-sector and energy-related industries in Canada. The ability to predict and apply structure-function relationships is critical to the invention and development of materials and matter used in devices, agriculture and the pharmaceutical industry. In addition to technical competences, the training environment provides opportunities to enhance skills such as effective communication and collaboration to enhance readiness for the career workplace. The goals of this research program are embraced through four objectives, interconnected through the necessity to develop routes by which to synthesize and functionalize pyrroles in a controlled and desired manner: 1.The design and development of routes to first-in-class tellurium-substituted BODIPYs (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes) will enable these molecular constructs to be evaluated as (complementary) photosensitizers and mass cytometry labels for use in biosensing. This research will involve the development of new and robust methodology for the synthesis and cross-coupling of tellurophenes, an achievement that will have impact far beyond pyrrole-based chemistry. 2.Synthetic methods towards aza-BODIPYs, stable dipyrrolic constructs that absorb/emit into the (far) red, will be investigated so that chiral motifs can be reliably incorporated: these molecular constructs have promise in dual-channel sensing. 3.Novel (bis)pyrrolic and bis(ruthenium)-pyrrolide triad frameworks featuring p-expansive (pi-expansive) linkers will be explored for their materials and photosensitizing properties. 4.Synthetic methods towards dipyrrolic azo-compounds will be determined, thereby providing a tunable new chemical class for use in photochemical switching and sensing.