Determination of the Molecular Arrangement Inside Cyanine Dye Aggregates by Magnetic Orientation

Abstract

We present a novel method for the determination of the internal structure of macromolecular aggregates in solution based on polarized absorption measurements on magnetically aligned aggregates. Different types of aggregates of three cyanine dyes were investigated in order to test the method. The obtained stacking geometries agree with those found by X-ray diffraction experiments on single crystals grown from the studied dyes, providing evidence that our method is a valuable tool for structural analysis of molecular assemblies.

Investigation of structure–spectroscopy–function relationship of two-dimensional J-aggregates of tetrachlorobenzimidazolocarbocyanine preferentially oriented in poly-vinyl-alcohol thin films

“…Nevertheless, the general suggestions on the structure, excited states and relaxation dynamics discussed above are expected to hold for other cyanine aggregates which show the same generic features [32][33][34]. Table 1 The structural parameters and the leading interaction strengths for the simulations.…”

Absorption spectrum of monomeric pseudoisocyanine: A new perspective and its implications for formation and spectral response of J-aggregates in solution and in thin films

“…The 525 nm peak is associated with the 0-0 transition while the 490 and 460 nm transitions are attributed to vibrational bands. We, however, note that this spectral shape does not share the seemingly universal fingerprint of cyanines which consists of a 0-0 transition and a ''single'' (0-1) vibrational shoulder [3][4][5]. Consequently, we have questioned this assignment which is widely accepted as a fact, while it is only a proposition which relies on the assumption that the PIC is monomeric under the conditions stated above.…”

“…Despite extensive investigation, the spectral changes following self-aggregation and the kinetics of aggregate formation in solution/thin films are still debated [3][4][5][6][7][8].…”

“…The Frenkel exciton picture [9] is well agreed as the basis for understanding their optical response [3][4][5][6][7][8]10]. The prerequisite to reveal the aggregate optical response within the Frenkel picture is a well-defined monomeric absorption spectrum.…”

Cyanines Bearing Quaternary Azaaromatic Moieties

“…It should be pointed out that in this field the dyes quaternized at the nitrogen atom of a six-membered 86 or five-membered 87,88 ring are investigated.…”