Fluorescence Behavior Associated with a Possible Intercolumnar Charge-transfer Interaction in the Crystalline State of a Dyad Consisting of Mesitylene and 1,4-Dicyano-2-methylnaphthalene Subunits

Abstract

ABSTRACT : Fluorescence (FL) properties of a novel donor–acceptor dyad, comprised of mesitylene and 1,4-dicyano-2-methylnaphthalene (DCMN) subunits connected by FL,Can ether linkage, were elucidated. The dyad in cyclohexane exhibits FL arising from an intramolecular exciplex. In the crystalline state, the dyad does not emit light from intra- and inter-molecular exciplexes but rather displays FL that is nearly equivalent to that of 2-methoxymethyl-substituted DCMN. However, the emission spectrum of the crystalline dyad contains a 361shoulder in the 0.39long wavelength region, suggesting that weak intercolumnar charge-transfer interactions take place between columns consisting of the mesitylene and DCMN subunits. An exciplex is an electronically-excited state complex comprised of two different molecules. 1 Mechanisms for inter- 2 and intra-molecular 3 formations and the photo-physical 4 and -chemical properties 5 of a number of exciplexes in solution have been studied. On the other hand, exciplexes in the crystalline states have gained much less attention. In a previous effort, we studied the fluorescence (FL) behavior of dyads containing a 1,4-dicyano-2-methylnaphthalene (DCMN) electron acceptor tethered to 4-methyl-, 4-methoxy-,