Solvation Of 5-fluorouracil In Supercritical Co2

The solvation properties of 5-fluorouracil in supercritical carbon dioxide (SC-CO2) is investigated by means of molecular dynamics computer simulations using a force field that treats all atoms explicitly. Solvation shell distribution functions and solvent density maps around the solute were computed at different supercritical temperatures in the range 308-328 K and densities varying from 0.117 to 0.94 g/cm3. At the lowest density, we detect a strongly inhomogeneous local density augmentation effect manifested as the clustering of solvent molecules above and below the solute molecular plane and around its carbonyl and N-H groups. The free-energy benefit for a CO 2 molecule to be in the first solvation shell relative to the bulk is roughly twice the thermal energy at such conditions. The distribution of the relative orientation of CO2 with respect to the solute suggests that local bond multipolar solute-solvent interactions are responsible for the solvent density enhancement in these systems. © 2008 Wiley Periodicals, Inc.1081325572563(1999) Chem Rev, 99 (2). , Noyori, R, Guest editor, Special Issue(2006) J Supercrit Fluids, 38 (2). , Erkeya, C, Kiran, E, Guest editors, Special IssueHutchinson, K.W., Foster, N.R., Innovations in Supercritical Fluids Science and Technology (1995) ACS Symposium Series, 608. , American Chemical Society: WashingtonEckert, C.A., Knutson, B.L., Debenedetti, P.G., (1996) Nature, 383, p. 313McHugh, M.A., Krokonis, V.J., (1994) Supercritical Fluids Extraction: Principles and Practice, , 2 nd ed, Butterworths: Boston, MAEckert, C.A., Liotta, C.L., Bush, D., Brown, J.S., Hallett, J.P., (2004) J Phys Chem B, 108, p. 18108Tucker, S. C.Maddox, M. W. J Phys Chem B 1998, 102, 2437Stephens, M.D., Saven, J.G., Skinner, J.L., (1997) J Chem Phys, 106, p. 2129Elles, C.G., Crim, F.F., (2006) Annu Rev Phys Chem, 57, p. 273Marcus, Y., (2005) J Phys Org Chem, 18, p. 373Patel, N., Biswas, R., Maroncelli, M., (2002) J Phys Chem B, 106, p. 7096Song, W., Biswas, R., Maroncelli, M., (2000) J Phys Chem A, 104, p. 6924Rocha, S. R. P.Johnston, K. P.Westacott, R. E.Rossky, P. J. J Phys Chem B 2001, 105, 12092Rocha, S. R. P.Johnston, K. P.Rossky, P. J. J Phys Chem B 2002, 106, 13250Fávero, F.W., Skaf, M.S., (2005) J Supercrit Fluids, 34, p. 237Guney, O., Akgerman, A., (2000) J Chem Eng Data, 45, p. 1049Suleiman, D., Estevez, L.A., Pulido, J.C., Garcia, J.E., Mojica, C., (2005) J Chem Eng Data, 50, p. 1234Harris, J.G., Yung, K.H., (1995) J Phys Chem, 99, p. 12021Vorholz, J., Harismiadis, V.I., Rumpf, B., Panagiotopoulos, A.Z., Maurer, G., (2000) Fluid Phase Equil, 170, p. 203Adams, J. F.Siavosh-Haghighi, A. J Phys Chem B, 2002, 106, 7973Frisch, M. J, Trucks, G. W, Schlegel, H. B, Scuseria, G. E, Robb, M. A, Cheeseman, J. R, Zakrzewski, V. G, Montgomery, J. A, Jr, Stratmann, R. E, Burant, J. C, Dapprich, S, Millam, J. M, Daniels, A. D, Kudin, K. N, Strain, M. C, Farkas, O, Tomasi, J, Barone, V, Cossi, M, Cammi, R, Mennucci, B, Pomelli, C, Adamo, C, Clifford, S, Ochterski, J, Petersson, G. A, Ayala, P. Y, Cui, Q, Morokuma, K, Malick, D. K, Rabuck, A. D, Raghavachari, K, Foresman, J. B, Cioslowski, J, Ortiz, J. V, Stefanov, B. B, Liu, G, Liashenko, A, Piskorz, P, Komaromi, I, Gomperts, R, Martin, R. L, Fox, D. J, Keith, T, Al-Laham, M. A, Peng, C. Y, Nanayakkara, A, Gonzalez, C, Challacombe, M, Gill, P. M. W, Johnson, B, Chen, W, Wong, M. W, Andres, J. L, Gonzalez, C, Head-Gordon, M, Replogle, F. S, Pople, J. A. Gaussian 98, Revision A. 7Gaussian, Inc: Pittsburgh, PA, 1998Kaminski, G.A., Friesner, R.A., Tirado-Rives, J., Jörgensen, W.L., (2001) J Phys Chem B, 105, p. 6474Ponder, J. W. TINKER Software Tools for Molecular Design, Version 3.9, 2000Tucker, S. C. Chem Rev 1999, 99, 391Rodriguez, J., Skaf, M.S., Laria, D., (2003) J Chem Phys, 119, p. 6044Laria, D., Skaf, M.S., (2002) J Phys Chem A, 106, p. 8066Raveendran, P., Ikushima, Y., Wallen, S.L., (2005) Acc Chem Res, 38, p. 478Fávero, F.W., (2007), PhD Thesis, Institute of Chemistry, State University of Campina