SYNTHESIS, STRUCTURE, AND FLUORESCENCE PROPERTIES OF 17-DISTYRYL-25,26,27,28-TETRAPROPOXYCALIX[4]ARENES IN THE CONE CONFORMATION

The HWE (Horner-Wadsworth-Emmons) reaction performed on the easily obt ainable 5,17-diformylcalix[4]arenes (cone) with arylmethyl phosphorus ylides yielded 5,17-distyryl-25,26,27, 28-tetrapropoxycalix[4]arenes ( cone) in high yield and purely in the E/E configuration. Compounds 2-5 were prepared this way containing bromine. Subsequent bromine-lithium exchange and reaction with trimethoxyborane yielded the dihydroxybory l-substituted 5,17-distyrylcalix[4] arenes 6-7a. The structures of 3, 5, and 7a were determined by X-ray diffraction. The photophysical prop erties of 2 were established by absorption and fluorescence spectrosco py and compared to the monomeric fluorophore, 3,5-dimethyl-4-propoxy-( E)-stilbene (10).