New ionic liquids for exploring molecular-scale interactions

I&EC 8

Hideaki Shirota, shirota@rutchem.rutgers.edu1, Edward W. Castner Jr., castner@rutchem.rutgers.edu1, Song H. Chung, ChungS@wpunj.edu2, Steven G. Greenbaum, sgreenba@hunter.cuny.edu3, and James F. Wishart, wishart@bnl.gov4. (1) Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854-8087, (2) Department of Chemistry and Physics, William Paterson University of New Jersey, 300 Pompton Road, Wayne, NJ 07470, (3) Department of Physics, Hunter College, CUNY, 695 Park Ave, New York, NY 10021, (4) Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973
Recent work in our research collaborations has focused on the study of several new ionic liquids, selected for the purpose of understanding the interactions and dynamics on a molecular scale. Many research groups have demonstrated that cation modification and anion substitution of the ionic liquids produce dramatic changes in the macroscopic physical properties of the ionic liquids, such as melting points, shear viscosity, conductivity, and glass transition temperature. Our focus is on the interactions between the molecular ions that collectively determine the macroscopic properties. We characterize the ionic liquid interactions using nonlinear optical studies of intermolecular vibrations and collective diffusive reorientation, and via NMR experiments on both translational and rotational diffusion. Time-resolved fluorescence probe studies allow determination of the effective local solvation polarity, solvation dynamics, and local friction of the ionic liquid.

Several classes of new ionic liquids will be discussed. These liquids have been designed to profile the intermolecular interactions that control significant physical properties. For example, substitution of alkylsilane, alkylsiloxy, or alkoxy side groups for alkyl chains leads to changes in local charge distributions and bond lengths (and hence molecular volumes). We also explore the effect of the ionic nature by comparing an ionic liquid with the analogous binary liquid that has two neutral components that are isoelectronic and isostructural to either the cation or the anion.

This work was supported by the National Science Foundation and ACS-Petroleum Research Fund (Rutgers), the Research Corporation (Wm. Paterson Univ. of NJ), and by the U.S. Department of Energy (CUNY, and at BNL under contract number DE-AC02-98-CH10866).

 

Ionic Liquids: Not Just Solvents Anymore OR Ionic Liquids: Parallel Futures (Sponsored by Green Chemistry and Engineering, Separation Science and Technology and Novel Chemistry with Industrial Applications Sub-Divisions)
8:15 AM-12:25 PM, Sunday, 26 March 2006 Georgia World Congress Center -- B314, Oral

Division of Industrial and Engineering Chemistry

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006