Experimental and Computational Study of BODIPY Dye-Labeled Cavitand Dynamics

Understanding
the distance distribution and dynamics between moieties attached to
the walls of a resorcin[4]­arene cavitand, which is switchable between
an expanded kite and a contracted vase form, might enable the use
of this molecular system for the study of fundamental distance-dependent
interactions. Toward this goal, a combined experimental and molecular
dynamics (MD) simulation study on donor/acceptor borondipyrromethene
(BODIPY) dye-labeled cavitands present in the vase and kite forms
was performed. Direct comparison between anisotropy decays calculated
from MD simulations with experimental fluorescence anisotropy data
showed excellent agreement, indicating that the simulations provide
an accurate representation of the dynamics of the system. Distance
distributions between the BODIPY dyes were established by comparing
time-resolved Förster resonance energy transfer experiments
and MD simulations. Fluorescence intensity decay curves emulated on
the basis of the MD trajectories showed good agreement with the experimental
data, suggesting that the simulations present an accurate picture
of the distance distributions and dynamics in this molecular system
and provide an important tool for understanding the behavior of extended
molecular systems and designing future applications.