DIVISION OF ENVIRONMENTAL CHEMISTRY

235th ACS National Meeting

New Orleans, LA

April 6-10, 2008

WEDNESDAY EVENING

Sensors for Detection and Quantification of Contaminants in Drinking Water and the Environment

Session 3

Cosponsored by WaterCAMPWS, ACS Division of Environmental Chemistry, and AIChE Environmental Division (Group 9) and ANYL
E. Morgenroth and P. W. Bohn, Organizers

6:00 - 8:00

291. Molecular association of benzene with a new cyclophane receptor. T. Buthelezi, C. Davies

ABSTRACTS

ENVR 291

Molecular association of benzene with a new cyclophane receptor

Thandi Buthelezi and Christopher Davies, Department of Chemistry, Western Kentucky University, 1906 College Heights Blvd #11079, Bowling Green, KY 42101-1048, Fax: 270-745-5361, thandi.buthelezi@wku.edu

Host/guest interactions in the cyclophane-2/benzene system have been investigated by absorption and fluorescence spectroscopy in dichloromethane. The cyclophane serves as a host and the benzene as a guest. Absorption and fluorescence titration experiments are carried out by keeping either the amount of the host or guest constant while varying the concentration of the other component. When the concentration of benzene is kept constant, an isostilbic point is observed in the fluorescence spectral data at 288 nm, suggesting that only two absorbing species are present in equilibrium. However, keeping the concentration of cyclophane-2 constant while increasing the concentration of benzene, results in a hyposchromic shift of the emission peaks in the range 275 to 360 nm. The shift is possibly due to the interaction of the cyclophane with benzene. The average association constant of cyclophane-2 with benzene, Ka = 425 ± 54 M-1, was obtained from fitting the absorption and the fluorescence spectral data to the Bourson equation using non-linear regression analysis.