On the Biexponential Decay of the Photoluminescence of the Two Crystallographically-Independent Molecules in Crystals of [Cu(I)(phen)(PPh3)2][BF4].
[Cu(I)(phen)(PPh3)2][BF4] crystallizes with two nonsymmetry-related molecules in the asymmetric unit. Synchrotron time-resolved X-ray diffraction experiments have shown that the two independent molecules distort differently on MLCT excitation. The luminescence decay of the crystals is biexponential with two different Stokes-shifts, the more rapid decay corresponding to the shorter wavelength emission. Its amplitude diminishes rapidly with an increase in temperature, indicating that this emission is not due to a thermal activation to a higher state. The double emission is attributed to the presence of two independent molecules with drastically different packing environments. It is concluded that the solid-state environment must be analyzed whenever photochemical properties of molecular solids are reported.
Chemistry Department, University at Buffalo, Buffalo, New York 14221, United States.
Philip
P
Coppens
Chemistry Department, University at Buffalo, Buffalo, New York 14221, United States.
Jesse
J
Sokolow
Chemistry Department, University at Buffalo, Buffalo, New York 14221, United States.
Elzbieta
E
Trzop
Chemistry Department, University at Buffalo, Buffalo, New York 14221, United States.
Anna
A
Makal
Chemistry Department, University at Buffalo, Buffalo, New York 14221, United States.
Yang
Y
Chen
effect of molecular environment; emission spectra; energy gap theory; excited state lifetimes; photocrystallography; time-resolved diffraction