Synthesis and Optical Properties of Near-Infrared (NIR) Absorbing Azo Dyes

Abstract

In this work, we have developed an efficient and simple protocol for the synthesis of novel A-π-D-π-A NIR azo dyes. The near infrared absorbing azo dyes were synthesized by using 2-hydroxy-1, 4 naphthoquinone (Lawsone) and different substituted aromatic primary amines. Furthermore, author developed push-pull chromophores of A-π-D-π-A type containing an electron-withdrawing azo core, phenazine moieties, and a hydroxyl group as electron donor. The benzo [a] quinoxalino [2,3-i] phenazin-5-ol moiety was introduced to make the system planer as well as to increase the π-conjugation. The optical properties of these dyes were studied in N, N-dimethylformamide (DMF).

2‐Hydroxy‐1,4‐naphthoquinone [Lawsone] integrated rare‐earth hybrid materials as biocompatible UV/IR filter agents

“…The stretching vibration of aliphatic and aromatic C–H group of the Lawsone molecules caused absorption in the range 2900–2840 cm −1 . The band at 1700–1600 cm −1 are related to the C ═ O of the organic moiety and the stretching vibrations due to C ═ C were resulted in the band range 1400–1300 cm −1 25–27 . Further, the existence of metal‐oxygen bonding in the hybrid systems was confirmed from the respective bands in the ranges 660–550 cm −1 and 1050–990 cm −1 , respectively 19 .…”

“…The band at 1700-1600 cm −1 are related to the C ═ O of the organic moiety and the stretching vibrations due to C ═ C were resulted in the band range 1400-1300 cm −1 . [25][26][27] Further, the existence of metaloxygen bonding in the hybrid systems was confirmed from the respective bands in the ranges 660-550 cm −1 and 1050-990 cm −1 , respectively. 19 The aforementioned facts confirmed the existence of organic-inorganic hybrid structure in the systems synthesized.…”

Photochemical Stability of a Cotton Fabric Surface Dyed with a Reactive Triphenodioxazine Dye

“…The NIR-CI method provides useful insights on sample components spatial distribution by a chemical image, enabling a sample chemical and/or physical heterogeneity degree evaluation. [34][35][36][37]. The obtained chemical images are visualized in the forms of threedimensional blocks of data, further implied in partial least squares-dynamic analysis (PLS-DA) with the Evince software.…”