Intermolecular distance (dm).
The intermolecular distance, orientation and number of porphyrins were easily controlled by arranging the desired sequence.
And its amplitude exhibited a nonlinear dependence on the averaged intermolecular distance.
Meanwhile, molecules of sulfonamide 5, as well as sulfonamide 6, were joined as a head-to-head type chain motif, with intermolecular distance equal to 6.91 Å.
They suggested the excellent FRET design enabling the amplification of fluorescence signal through the fine tuning of the intermolecular distance by the electrostatic interaction between optical platforms.
Thus, due to steric and geometrical complementarities, parallel molecules of 6 form chains of the head-to-head type, with an intermolecular distance equal to 6.82 Å.
It means that intermolecular distance in film state was closed, and intermolecular π-π* interaction was increased because of no bulky side group.
Thus, the changes in the fluorescence spectra by FRET can be expected, if intermolecular distance between dyes is sufficiently close for FRET.
The results show that the introduction of long alkyl chains would lead to a more compact packing, and increase electronic coupling, but reduce intermolecular distance.
An X-ray crystallographic analysis revealed a π-stacked column with a short intermolecular distance in the crystals of the 2,6-isomer.
Such an observation implies that the intermolecular coupling (IMC) which is modulated by changing the intermolecular distance is able to significantly affect the intensity of fission process.
