Electronic
absorption spectra were recorded using a Jasco V-630 spectrophotometer.
Emission spectra were measured on a Jasco FP 6600
spectrofluorometer. Mass spectral studies were carried out on a
Hewlett-Packard 5989B MS. 1D and 2D NMR experiments were
performed on a Bruker Avance III spectrometer at 400 MHz.