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Maria Ngu-Schwemlein

James Davis
Professor of Chemistry
(251) 460-6181

It is probably safe to say that five years ago most chemists had never heard of ionic liquids, a class of materials which is the principal focus of our work. But, in that short period of time interest in these unorthodox materials has grown at a phenomenal rate. The scope of demonstrated or proposed applications of ILs is extraordinary, ranging from their use as non-volatile, non-flammable solvents to catalysts, materials for aiding separations, advanced heat transfer fluids, lubricants and anti-statics. Surpassing in magnitude the number of potential uses is the number of possible IL compositions, estimated by Seddon (Queen's University, Belfast ) to be in the billions.

In the absence of predictive computational methods to direct their design, the discovery-based development of new IL will remain vital to the field. It is this effort – the design, synthesis, and evaluation of new ionic liquids – that is the principal focus of our work (supported largely by Chevron).

Our efforts to create new ionic liquids fall into three overarching categories. The first is in the area of “task-specific” ionic liquids (TSILs), a subgroup of ionic liquids first described by us in 1999 and first referred to as TSILs in 2000. TSIL – type ionic liquids may be distinguished from more “conventional” ionic liquids in that the anion, cation or both of the salt contains within its structure a “functional group” which (by design) imbues the salt with a specific chemical attribute. One such family of ionic liquids that has been prepared by our group contains appended amine groups, which allow the ionic liquids to act as scavengers for CO 2 , a process of considerable commercial importance. An ORTEP of one such amine cation (here as its BPh 4 - salt) is shown below [X-ray structure courtesy of Professor Robin Rogers, University of Alabama ].

The second general area of ionic liquids development by our group concerns the identification of recognizably non-toxic ions for evaluation in the formulation of ionic liquids. While the overwhelming focus of most IL research worldwide has to date centered on their eventual use as inductrial solvents, we believe that appropriately non-toxic ionic liquids are tremendously promising materials for use in consumer products. By in large, our energies in this effort have been focussed on the identification of anions which might be suitable for IL formulation but which do not contain fluorine, a common component of most IL-anions. So far, we have established that the “docusate” anion (a common drug and cosmetic ingredient on the FDA GRAS list) is quite compatible with the formation of ionic liquids, as are the active (anionic) ingredients in saccharine and acesulfame based artificial sweeteners.

Most recently our attention has turned to examining the use of a long-neglected boron-centered cation type – the “boronium ion” –in creating new ionic liquids. Our first success in this regard was recently reported in Chemical Communications (2005) and the development of new boronium based materials is an area of growing interest on our part. Boronium ions are both isosteric and isoelectronic to classical ammonium ions, but differ substantially in the distribution of charge within their structures compared to their classical ammonium analogs. In the boronium ions, the positive charge is more extensively delocalized than in the conventional counterpart. This is readily seen in the computed electron distributions of an imidazolium-boronium ion and its conventional counterpart (1 and 1C respectively in the Figure below).

Finally, it bears noting that our department – as well as the Davis group – is solely undergraduate in nature (no graduate students, no postdoctoral fellows); The high tempo of research activity in our group and the department overall is a testimony to the talents and work ethic of our students!

We invite you to learn more about Davis group research activities by exploring the links on this page.

Recent Journal Publications

Four of these publications (preceded by an asterisk) were recently determined by Thomson/ISI Web of Science to be in the top 1% of the most frequently cited papers in ionic liquids chemistry. USA undergraduate co-authors are underlined.

Monograph Chapters

The chapter cited in reference 8 (below) was the first to introduce the term “task-specific” ionic liquids (TSILs), a concept proposed by our group in a 1999 Tetrahedron Letters paper

Patents & Commercial Licenses

Davis Group in the News


University of South Alabama - Mobile, AL, 36688-0002, (251) 460-6181
Date Last Changed: September 19, 2007 1:40 PM

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