Our research makes use of synthetic, mechanistic, and analytical chemistry to understand basic scientific principles underlying photochemical phenomena in organized molecular architectures. Because photosynthesis is paradigmatic our chief focus concerns the fundamental chemistry of tetrapyrrole macrocycles.
We have been working to develop molecular building blocks of naturally occurring tetrapyrrole macrocycles. Such macrocycles (heme, chlorophylls, bacteriochlorophylls, vitamin B12, F430) are Nature’s most important cofactors and perform unique photochemical, redox, and catalytic functions. We have developed versatile routes for the synthesis of porphyrins and chlorins; our chief focus now concerns bacteriochlorins, which absorb near-infrared light and are of interest for applications in the life sciences, photomedicine, and materials science. New synthetic routes to this fascinating class of compounds are under intense development.
Artificial photosynthesis embodies the longstanding “green” challenge to harvest sunlight for mankind’s uses. To study photosynthetic-like processes, we have been incorporating tetrapyrrole building blocks (of porphyrins, chlorins, and bacteriochlorins) in diverse molecular architectures including synthetic arrays, designer proteins, films and liposomes. We also continue to develop databases for incorporation into PhotochemCAD™. The spectroscopic and physical studies of the artificial photosynthetic constructs are carried out by our longtime collaborators David F. Bocian and Dewey Holten.
Origins of life
How life originated remains one of the great, unsolved problems of modern science. We are investigating simple, spontaneous chemical routes that create prebiotic molecules. A key challenge is to understand the molecular requirements for the origin of the essential pigments (e.g., proto-chlorophylls) central to the emergence of an early (Hadean- or Achaean-era) proto-photosynthesis. In this regard, we recently discovered a new non-enzymic pathway to uroporphyrinogens, of which isomer III is the last common (and universal) modern precursor to all of Nature’s tetrapyrroles.
General questions of interest include: How did specific biomolecules form and how were they selected from the vastness of chemical space? Do such molecules self-organize in lipid assemblies to give functional protocells? Was photochemistry the critical driving force for the origin of life on Earth? This project encompasses a broad range of experimental skills including organic, inorganic, bioanalytical, and biophysical chemistry.