Effect of phenyl ring substitution on J-aggregate formation ability of novel bisazomethine dyes in vapour-deposited films

Abstract

Bisazomethine dyes, which are synthesized using diaminomaleonitrile and aminobenzaldehydes, exhibit red fluorescence in solution and in the solid state. Several bisazomethine dyes are known to form Jaggregates in vapour-deposited films. In this work, novel bisazomethine dyes were synthesized and the effect of phenyl ring substitution on the J-aggregate formation in vapour-deposited films was examined. The optical properties of the dyes were examined in solution and in the solid state through molecular orbital calculations. Four derivatives were found to form J-aggregates in vapour-deposited films as determined from the shape of the spectrum and the absorption edge.

Spectroscopic Indicators of Diaminomaleonitrile Bisubstitution: A Review

“…According to UV-Vis, all ligands displayed high molar extinction coefficients (εmax>100,000) around 550 nm, which belong to symmetric ligands with strong ICT processes according to Matsuoka [9] and Kim [35]. IR spectroscopy indicated that the 14 ligands had a single nitrile band in the 2208-2201 cm -1 interval.…”

“…Matsumoto and col. [9] realized the synthesis of 14 symmetric ligands with different alkoxy-derived substituents. The synthesis process was according to Figure using DAMN as the precursor.…”

“…DAMN has been used in the synthesis of purines, 4,5-dicyanoimidazoles, 5,6-dicyanopyrazines, and amides [1]. Additionally, is a precursor of Schiff base ligands and complexes with applications in: organic solar cells [6] [7], catalysis [8], optoelectronics [9] [10], optical materials [5] [11] [12] [13], fluorescent materials [14] [15] [16], antimicrobial agents [17], heterocyclic synthesis [18], and conjugated polymers [19]. It´s known in the literature that DAMN tends to condense monosubstituted ligands even in excess of the precursor aldehyde [20] [21].…”

The effect of terminal dimethyl and diethyl substituents on the J-aggregate-like molecular arrangement of bisazomethine dye molecules

“…Bathochromic absorption shifts in vapour deposited films of 1a-1f have been reported. 28 The single crystal X-ray structures of 1a-1f indicate that the J-aggregate-like 2-D molecular stacking layers formed in 1b-1f, but 1a did not form these 2-D layers. A dislocation of the π-π stacked molecules along the short molecular axes was found in the 2-D layers of 1b-1f, this is similar to that of the DEA derivatives with decyloxy substituents.…”

“…The DEA derivatives show J-aggregate-like bathochromic absorption shifts between the solution state and solid state, for example, in vapour deposited films. 28 Crystal structures of the dye molecules show that they form J-aggregate-like two-dimensional (2-D) stacked layers. 30,35 The features of the crystal structures of the nine reported DEA derivatives are schematically summarised in Figure 1.…”