Research Interests
Solid State Synthesis

Green chemistry seeks to reduce or eliminate use or generation of hazardous substances in the design and application of chemical products. In such a context, a main goal of green chemistry is the development of alternative reaction media for chemical syntheses. When planning a synthesis, a fundamental question that arises is the nature of the medium within which to perform a reaction. Traditionally, this question has focused upon choice of solvent since most organic and inorganic reactions are conducted in the liquid phase. Many such solvents (e.g. methylene chloride, benzene), however, have been classified, under the United States' Clean Air Act, as volatile organics (VOCs), compounds to avoid owing to their volatility and deteriorating effects on organic matter, as well as the ozone layer. This means that synthetic processes that utilize alternative solvents, or, more generally, alternative reaction media, which avoid use of VOCs are highly desirable. Moreover, the successful design of a medium that replaces VOCs in synthetic chemistry has a potential to affect broad classes of compounds since ideas embodied within green chemistry are applied to all chemical processes that occur within the medium.

Our group is currently developing the solvent-free environment of the solid-state as a medium for conducting organic synthetic chemistry. To this end, we are utilizing molecules that function as linear templates, in a similar way to the structure of DNA, to direct organic reactions in solids by way of hydrogen bonds. Specifically, we have demonstrated the ability of resorcinol, and derivatives, to induce alignment of C=C double bonds in the solid-state (Fig. 1) such that the two reactive sites undergo a photoinduced [2+2] addition reaction, forming two C-C single bonds, the very foundation of organic chemistry. This method has enabled us to conduct molecular synthesis by design (e.g. synthesis of cyclophanes), a concept central to the development of liquid phase organic synthesis (e.g. natural product synthesis), and we are currently applying this approach to: 1) traditional problems of organic synthesis and 2) a prospect of constructing molecules unavailable in the liquid phase. Once solid-state reaction is complete, we are able to recycle the template for additional synthesis.

Figure 1. Crystal structure of (a) 2(resorcinol)·2(1,2-trans-bis(4-pyridyl)ethylene and (b) 2(resorcinol)·(rctt-tetrakis(4-pyridyl)cyclobutane).