TY - JOUR
T1 - Origins of the differences in solvation by alkanes and perfluoroalkanes. Evidence from the S2-S0 spectra of jet-cooled van der Waals complexes of xanthione and azulene
AU - Sinha, H. K.
AU - Abou-Zied, O. K.
AU - Ludwiczak, M.
AU - Maciejewski, A.
AU - Steer, R. P.
N1 - Funding Information:
The authors gratefully acknowledget he financial support of the Natural Sciencesa nd Engineering Re-searchC ouncil of Canada and the Centres of Excellence in Molecular and Interfacial Dynamics.
PY - 1994/12/9
Y1 - 1994/12/9
N2 - The S2-S0 fluorescence excitation spectra ofxanthione (XT) and azulene (AZ) complexed with 1 or 2 molecules of the C1 to C10 n-alkanes and the C1 to C6 perfluoro-n-alkanes have been measured. The 1:1 complexes exhibit microscopic solvent shifts, Δ \ ̄gn, which are larger for the alkanes than the corresponding perfluoroalkanes, despite the larger molecular polarizability of the latter. The values of Δ \ ̄gn increase monotonically with carbon number of the adduct to C10 in 1:1 n-alkane complexes with XT and to C5 in 1:1 n-alkane complexes with AZ. However, Δ \ ̄gn exhibits no further increase beyond C2 in 1:1 perfluoro-n-alkane complexes with XT and beyond C3 in 1:1 perfluoro-n-alkane complexes with AZ. The results are interpreted in terms of a model in which the n-alkanes stretch out along the long axis of the chromophore and 'wet' its surface whereas the perfluoro-n-alkanes with carbon numbers ≥ 3 away from the surface of the chromophore and are 'non-wetting'.
AB - The S2-S0 fluorescence excitation spectra ofxanthione (XT) and azulene (AZ) complexed with 1 or 2 molecules of the C1 to C10 n-alkanes and the C1 to C6 perfluoro-n-alkanes have been measured. The 1:1 complexes exhibit microscopic solvent shifts, Δ \ ̄gn, which are larger for the alkanes than the corresponding perfluoroalkanes, despite the larger molecular polarizability of the latter. The values of Δ \ ̄gn increase monotonically with carbon number of the adduct to C10 in 1:1 n-alkane complexes with XT and to C5 in 1:1 n-alkane complexes with AZ. However, Δ \ ̄gn exhibits no further increase beyond C2 in 1:1 perfluoro-n-alkane complexes with XT and beyond C3 in 1:1 perfluoro-n-alkane complexes with AZ. The results are interpreted in terms of a model in which the n-alkanes stretch out along the long axis of the chromophore and 'wet' its surface whereas the perfluoro-n-alkanes with carbon numbers ≥ 3 away from the surface of the chromophore and are 'non-wetting'.
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U2 - 10.1016/0009-2614(94)01187-7
DO - 10.1016/0009-2614(94)01187-7
M3 - Article
AN - SCOPUS:0000906165
SN - 0009-2614
VL - 230
SP - 547
EP - 554
JO - Chemical Physics Letters
JF - Chemical Physics Letters
IS - 6
ER -