Intramolecular photoassociation and photoinduced charge transfer in bridged diaryl compounds. 1. Photoassociation in the lowest triplet state of 2,2'-dinaphthylmethane and 2,2'-dinaphthyl ether

Formation of intramolecular triplet excimers in bridged diaryls is demonstrated for 2,2'-dinaphthylmethane (2,2'-DNM) and 2,2'-dinaphthyl ether (2,2'-DNE) using time-resolved absorption and emission (fluorescence and phosphorescence) spectroscopy. Comparison of the spectra of the ground-state dimer trapped in low-temperature glassy matrices with those of the molecules in fluid solution at room temperature suggests that the conformation of the intramolecular triplet excimers is similar to that of the corresponding ground-state-formed van der Waals dimers. Triplet-triplet annihilation of the excimer leading to the formation of the intramolecular excited singlet dimer at room temperature is also reported.