Intramolecular triplet energy transfer in benzophenone-{crown ether}-naphthalene system

Abstract

Bichromophoric compound benzophenone-{crown ether}-naphthalene (Bp-C-Np) was synthesized and its photophysics was examined. Steady state and time-resolved spectroscopic measurements indicate that intramolecular energy transfer from the triplet state of the benzophenone chromophore to the naphthyl group in Bp-C-Np occurs with efficiency of ca. 33% and rate constant of ca. 3.3 × 10 5 s -1 . This long-distance triplet energy transfer is proposed to proceed via a through-bond exchange mechanism.

Triplet energy management between two signaling units through cooperative rigid scaffolds

“…In flexible bridge-linked D-A systems, a rapid conformational equilibrium leads to spatial arrangements, in which the two chromophores are close enough for orbital overlap within the lifetime of the donor triplet, so that TTET happens through-space. [3][4][5][6][7][8][9][10][11] Conversely, in the case of rigid saturated hydrocarbon bridges, in which D and A distances are substantially longer than the sum of the van der Waals radii, TB mechanism is largely predominating. [12][13][14][15][16][17][18][19][20][21] In these systems, the observed TTET happening TB is facilitated by the s and s* orbitals of the bridge and, in general, is strongly dependent on the conformations.…”