No abstract

Methyl-substituted derivatives of 1,3,5-tris(diphenylamino)benzene (TDAB) are found to show unique solid-state morphology, as characterized by differential scanning calorimetry and X-ray diffraction. These compounds readily form stable amorphous glasses having glass-transition temperatures of ca. 50 °C. p-Methyl-substituted TDAB exhibits polymorphism.

The resonance-enhanced two-photon ionization (RE2PI) and laser-induced fluorescence excitation spectra were recorded for the S(1)-S(0)(pipi( *)) region of the 7-azaindole(ethanol)(n) (n=1-3) [7AI(EtOH)(n) (n=1-3)] clusters in the gas phase to investigate the geometrical structures and the multiple-proton/hydrogen atom transfer reaction dynamics. Four and two structural isomers were identified for 7AI(EtOH)(2) and 7AI(EtOH)(3), respectively. Density functional theory calculations at the B3LYP/6-31++G( * *)/6-31G( *) level predicted four different conformations of the ethyl group for 7AI(EtOH)(2), in good agreement with the observation of the four structural isomers in the RE2PI spectra. Visible fluorescence from the tautomeric forms was observed in the S(1) states for all isomers of 7AI(EtOH)(2), but no sign of double-proton/hydrogen atom transfer and quadruple-proton/hydrogen atom transfer has been obtained in the electronic spectra of 7AI(EtOH)(1) and 7AI(EtOH)(3), respectively. These results suggest that the multiple-proton transfer reaction is cluster-size selective, and the triple-proton/hydrogen atom transfer potential is dominated by the cyclic hydrogen-bonded network in 7AI(EtOH)(2). The excitation of the in-phase intermolecular stretching vibration prominently enhances the excited-state triple-proton/hydrogen atom transfer reaction.

With the aim of developing photo-and electro-active amorphous molecular materials, a novel starburst molecule, 1,3,5-tris[N-(4-diphenylaminophenyl)phenylamino] benzene, has been synthesized, and its molecular and solid-state properties investigated. It readily forms a stable amorphous glass with a glass-transition temperature (T,) of 108 "C when cooled from the melt, as characterized by differential scanning calorimetry and X-ray diffraction. The compound provides an example of a stable photo-and electro-active amorphous molecular material, with a relatively high T,, that hardly undergoes crystallization even on heating above T,.

A new class of n-electron starburst molecules, 1,3,5-tris(4halogenophenylphenylamino) benzenes, are synthesized for use as amorphous molecular materials. It was found that they readily form amorphous glasses, whereas the parent compound 1,3,5-tris(diphenylamino) benzene instantly crystallizes and that the ease of glass formation, glasstransition temperature, and stability of the glassy state are greatly affected by the type of halogen substituent.