J-aggregates are of significant interest for organic materials conceived by supramolecular approaches. Their discovery in the 1930s represents one of the most important milestones in dye chemistry as well as the germination of supramolecular chemistry. The intriguing optical properties of J-aggregates (in particular, very narrow red-shifted absorption bands with respect to those of the monomer and their ability to delocalize and migrate excitons) as well as their prospect for applications have motivated scientists to become involved in this field, and numerous contributions have been published. This Review provides an overview on the J-aggregates of a broad variety of dyes (including cyanines, porphyrins, phthalocyanines, and perylene bisimides) created by using supramolecular construction principles, and discusses their optical and photophysical properties as well as their potential applications. Thus, this Review is intended to be of interest to the supramolecular, photochemistry, and materials science communities.

J-aggregates: from serendipitous discovery to supramolecular engineering of functional dye materials.

Cyanines during the 1990s: A Review

Über Pyridinium-N-phenol-betaine und ihre Verwendung zur Charakterisierung der Polarität von Lösungsmitteln

A two-state, four-orbital, independent electron analysis of the first optical molecular hyperpolarizability, β, leads to the prediction that |β| maximizes at a combination of donor and acceptor strengths for a given conjugated bridge. Molecular design strategies that focus on the energetic manipulations of the bridge states are proposed for the optimization of β. The limitations of molecular classes based on common bridge structures are highlighted and more promising candidates are described. Experimental results supporting the validity of this approach are presented.

https://science.sciencemag.org/content/sci/252/5002/103.full.pdf

Approaches for Optimizing the First Electronic Hyperpolarizability of Conjugated Organic Molecules

The purpose of this study was to find a 488-nm excitable fluorescent dye for reticulocyte analysis by the use of fluorescence activated cell cytometry. The chemical structure of thioflavin T, a dye used for reticulocyte analysis with 457-nm excitation, was used as a model. Several dyes were synthesized and evaluated by quantum yield determination, fluorescence microscopy, and flow cytometry. The best results were obtained with a dye we have named “thiazole orange”; analysis of several blood samples with thiazole orange gave a correlation coefficient of 0.97 as compared to a manual determination of reticulocyte percentage.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/cyto.990070603

Thiazole orange: a new dye for reticulocyte analysis.

Color and Constitution. X.1 Absorption of the Merocyanines2

Studies in the Cyanine Dye Series. XI.1 The Merocyanines

Color and Constitution. VII.1 Interpretation of Absorptions of Dyes Containing Heterocyclic Nuclei of Different Basicities

Photographic sensitizers may be classified according to the freedom of relative motion of the parts of the molecule as “loose,” “compact,” or “crowded.” The first two of these categories comprise planar and the third non-planar molecules. Compactness is especially favourable for dye aggregation. Sheppard's correlation between planarity and strong sensitization is confirmed, and amplified to stress the marked loss of sensitization which can accompany slight distortion from planarity.

Grafton H Keyes

Papers

Color and Constitution. X.1 Absorption of the Merocyanines2

Studies in the Cyanine Dye Series. XI.1 The Merocyanines

Color and Constitution. VII.1 Interpretation of Absorptions of Dyes Containing Heterocyclic Nuclei of Different Basicities

Spatial Configuration, Light Absorption, and Sensitizing Effects of Cyanine Dyes*†

Color and Constitution. II.1 Absorptions of Some Related Vinylene-Homologous Series*