Caution Notice:
It has come to our notice that certain fraudulent individuals or entities are misusing our Company’s name and TCI’s registered trademarks by promoting and offering for sale regulated and hazardous chemical substances, including Potassium Cyanide, through online platforms like YouTube. We hereby categorically clarify that TCI has no association or connection whatsoever with the products being displayed or sold in these or similar videos. These products have been falsely represented as being associated with TCI, and the unauthorized use of our trademark and brand name is both illegal and misleading. TCI Chemicals is a responsible global organization committed to adhering to all applicable international and domestic regulatory frameworks. We do not manufacture, distribute, or engage in the sale of regulated chemical substances in India or in any other jurisdiction unless specifically authorized by the relevant laws and regulatory agencies. All our operations and offerings are governed by stringent safety, quality, and compliance protocols in accordance with applicable laws. Further, TCI Chemicals markets and sells its products exclusively through its official website and authorized distributors. We do not sell, endorse, or supply our products through any third-party platforms, unauthorized agents, or resellers. Any individual or organization purchasing products outside these official channels does so at their own risk, and TCI disclaims all responsibility and liability for any consequences arising therefrom. Members of the public, customers, and partners are strongly advised to exercise caution and conduct due diligence before engaging in any transactions involving products claiming association with TCI Chemicals. The official list of our authorized distributors is publicly available and may be accessed at: https://www.tcichemicals.com/IN/en/distributor/index. We are currently pursuing appropriate legal remedies against those misusing our brand, and we reserve all rights available to us under applicable intellectual property and criminal laws. If you become aware of any such fraudulent activity or require clarification, you may reach out to us at: Sales-IN@TCIchemicals.com. Your vigilance and cooperation are essential in safeguarding the public interest and protecting the integrity of the TCI brand.
Maximum quantity allowed is 999
Photochromic Dyes
Chromism is a phenomenon that reversibly changes optical properties (eg. photo absorption and emission) by an external stimulus. A molecular structure changes in many cases while chromism occurs, and then refractive index, dielectricity, redox potentials, and melting point also change. Photochromism is a photo-induced chromism. Photochromic materials are further developed for a light-modulating materials, optical recording media, optical switches, and functional inks.
A structural isomerization during photochromism involves photo-induced geometrical isomerizations (eg. cis-trans isomerization) and photo-induced ring-opening and -closure reactions. Fischer et al. first reported the photochromic behavior of spiropyrans.1) UV irradiation to a spiropyran undertakes a ring-opening of the spiro carbon. The structural change leads to a blue shift of photo absorption up to the visible region. Irie et al. first observed photochromism of diarylethenes.2) The diarylethene also shows photo-induced ring-opening and -closure reactions. UV irradiation to the diarylethene undertakes a ring-closure (with coloration) whereas a spiropyran does a ring-opening (with coloration) by UV irradiation. The ring-opened spiropyran thermally closes the ring (T-type). On the other hand, the ring-closed diarylethene is thermally stable but opens to form the original compound by visible light irradiation (P-type). It is well known that diarylethene is a photochromic compound with high photo sensitivity and repetition durability.3) A fulgide is also a P-type photochromic compound exhibiting a ring-closure by a photo irradiation.4)
Hayashi and Maeda observed photochromism of an imidazole dimer, hexaarylbiimidazole (HABI).5) A light irradiation to HABI undertakes dissociation of the dimer. The photochromic mechanism is different from those of the others doing photo isomerizations. A triphenylimidazolyl radical formed by the dissociation thermally recombines to reform the original HABI, thus this is a T-type photochromism. The triphenylimidazolyl radical is also useful as a photopolymerization initiator.6)
References
- 1) E. Fischer, Y. Hirshberg, J. Chem. Soc. 1952, 4522.
- 2) Review: M. Irie, Chem. Rev. 2000, 100, 1685.
- 3) K. Matsuda, M. Irie, TCIMAIL 2003, number 120, 2. [PDF]
- 4) J. Harada, R. Nakajima, K. Ogawa, J. Am. Chem. Soc. 2008, 130, 7085.
- 5) K. Maeda, T. Hayashi, Bull. Chem. Soc. Jpn. 1969, 42, 3509.
- 6) Review: B. M. Monroe, G. C. Weed, Chem. Rev. 1993, 93, 435.
