The Synthesis and Dichroic Properties of the Squarylium Chromophores

Soo-Youl Park; Griffiths John

Journal of Industrial and Engineering Chemistry, Vol.8, No.1, 77-81, January, 2002

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The Synthesis and Dichroic Properties of the Squarylium Chromophores

Soo-Youl Park^†, and Griffiths John¹

Department of Applied Chemistry, Korea Research Institute of Chemical Technology, Taejon 305-600, Korea
¹Department of Colour Chemistry, University of Leeds, Taejon 305-600, UK

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Over the last few decades, liquid crystals have made a noticeable impact in the commercial world as a result of their application and development in new display technologies to interface with the increasing number of electro-optical devices. For example, the use of a dichrioc dye (the guest) dissolved in a liquid crystal (the host) to make electrode transmission mode display devices. As a result the dichroic dye is characterised as dye structure with maximum absorbance along their principal axis and minimum absorbance along their minor axis. Now such dyes are used in potable computer and video devices. Particular, some squarylium compounds based on donor-acceptor chromophores have a very intense, narrow absorption band and also have a long rod-like molecular structure. Our results show that squarylium dyes could be produced excellent dichroic properties and are of practical use for guest-host LCDs. Also, the squarylium compounds based on donor-acceptor chromophores were investigated and the visible absorption spectroscopic properties of the various squaryliums were examined. Our results show that squaryliums could be possible to be produced near-infrared absorbing materials with a view to investigate colour.

Keywords:liquid crystal;dichroic dyes;chromophores;near-infrared

[References]

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[Related Articles]

[1] Schmidt AH, Synthesis, 961 (1980)

[2] Law KY, Facci JS, Bailey FC, Yanus JF, J. Imaging Sci., 34, 31 (1990)

[3] Nakazuml FH, Matsuoka M, Chem. Rev., 92, 1197 (1992)

[4] Emmelius M, Pawlowski G, Vollmann H, Angew. Chem., 101, 1475 (1989)

[5] Gravesteijn DJ, Steenbergen C, Vander V, J. Proc. SPIE. Int. Soc. Opt. Eng., 420, 327 (1988)

[6] Yuzhakov, Russ VI, Chem. Rev., 48, 1076 (1979)

[7] Bello KA, Ajayi JO, Dyes Pigments, 31, 79 (1996)

[8] Kim MS, Park SM, Kim HK, J. Ind. Eng. Chem., 6(3), 144 (2000)

[9] Pariser R, Parr RG, J. Chem. Phys., 21(466), 767 (1953)

[10] Lewis W, Experiments and Observations on American Potashes with an Easy Method of Determining their Respective Qualities., Elsevier London (1967)

[11] Sprenger HE, German Patent, 1,618,211 (1971)