Welton, United Kingdom
Welton, United Kingdom

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Choi J..-H.,Kyungpook National University | Choi J..-Y.,Kyungpook National University | Kim E..-M.,Kyungpook National University | Kim J..-P.,Seoul National University | And 2 more authors.
Coloration Technology | Year: 2013

The coloration properties and clearability of disperse dyes prepared from phthalimide-derived diazo components and a coupling component containing two carboxylic acid ester groups have been investigated. Members of the series featured C2-C4 alkyl substituents on their phthalimidyl nitrogen atom. The nature of the N-alkyl group made no consistent difference to dye uptake on polyester. No correlation was found between percentage exhaustion and calculated solubility parameters. Wash fastness was extremely good. Comparison with analogues indicated that the diester motif was of significant extra benefit to wash fastness for phthalimide-derived dyes, but did not increase photostability above the lower range of commercial acceptability. Clearability was compared with that of dyes lacking one or both hydrolysable structural features, as well as with that of some industrial dyes. The novel dyes exhibited a greater tendency to be solubilised, consistent with hydrolysis of their ester and/or phthalimide functionalities. © 2013 Society of Dyers and Colourists.


Mustroph H.,FEW Chemicals GmbH | Ernst S.,FEW Chemicals GmbH | Senns B.,FEW Chemicals GmbH | Towns A.D.,Vivimed Labs Europe Ltd
Coloration Technology | Year: 2015

The creation of the first synthetic dyes not only stimulated the hunt for new colorants but also drove the search for rules correlating the constitution of organic compounds with their colour. Dye chemistry additionally facilitated the development of molecular electronic spectroscopy as well as theories of molecular electronic structure and electronic transitions. Powerful quantum chemical computational tools are now available for the prediction of the electronic structure and spectroscopic characteristics of organic compounds. Such methods are thus useful in designing new functional colorants and aiding interpretation of their properties. However, without a deep appreciation of the principles and assumptions behind the calculations, one runs the risk of misunderstanding what can be achieved as well as becoming confused about how the outputted electronic and vibronic transition data correspond to observed absorption spectra. This review therefore aims to cover fundamentals of electronic spectroscopy that are often overlooked and enable the dye chemist using modern computational methods to comprehend the subtle differences in the types of transition energy value that such software can generate. In addition, the limitations of these methods in predicting absorption maxima and intensities of real-world colorants will be discussed in the context of physical influences on absorption band position and shape, for example from the perspective of different forms of the Franck-Condon principle. In essence, the goal of this review is to clarify, in terms that practical dye chemists will understand, what computational methods can predict and how valid these predictions are compared with reality. © 2015 Society of Dyers and Colourists.


Partington S.M.,Vivimed Labs Europe Ltd. | Towns A.D.,Vivimed Labs Europe Ltd.
Dyes and Pigments | Year: 2014

The impact of substituents on the photochromism of some spirooxazines has been explored. A series of photochromic spiroindolino[2,1-b][1,4]naphthoxazine dyes was prepared with varying alkyl substitution patterns in the 3- to 6-positions of the indoline system. It was found that placing methyl functions onto the phenyl ring produced bathochromic shifts in λmax of the photomerocyanine as expected, but contrary to literature indications lowered photocoloration half-life. However, replacing the 3,3-dimethyl pattern with 3-ethyl-3-methyl substitution led to more intense photochromism: half-life increased without affecting λmax. In contrast, introduction of a cyclohexyl ring to give a 3,3-pentamethylene fragment and substitution at the 5′-position of the naphthoxazine moiety with either ester or hydroxymethyl groups significantly increased the speed of fade in general contrast to literature reports for analogous dye series. Similar effects were also observed concerning alkyl substitution in a smaller synthesised set of photochromic [1,2-b][1,4]oxazines. © 2014 Elsevier Ltd. All rights reserved.


Patent
Vivimed Labs Europe Ltd | Date: 2012-05-02

A photochromic polymer comprising at least two photochromic moieties linked by a straight or branched chain polymer selected from the group consisting of poly(C2 to C4 alkylene oxide), poly[C_(1 )to C_(10 )alkoxy substituted (C_(2 )to C_(4 )alkylene oxide)] and poly[C_(1 )to C-_(15 )acyloxy substituted (C_(2 )to C_(4 )alkylene oxide)].


Choi J.-H.,Kyungpook National University | Kwon O.-T.,Kyungpook National University | Lee H.-Y.,Kyungpook National University | Towns A.D.,Vivimed Labs Europe Ltd | Yoon C.,Sejong University
Coloration Technology | Year: 2010

The synthesis and spectroscopic properties of monoazo dye series, whose members consist of N-alkylphthalimide diazo components combined with a coupling component containing two ester groups, are reported. Such colourants are potentially alkali-clearable as a consequence not only of the presence of diester functionality on the coupler, but also through use of the base-sensitive phthalimide system. Shortening the N-alkyl group by removing one or two methylene units from a butyl chain made little difference to absorption properties, as would be expected given the relatively minor differences in inductive character produced. Shifts in the absorption maximum of the dyes associated with dibromination of the phthalimidylazo motif and its subsequent cyanodehalogenation were in agreement with theory and literature data for related series. Diester substitution on the coupling component brought about hypsochromism and hypochromism. © 2010 The Authors. Journal compilation © 2010 Society of Dyers and Colourists.


Patent
Vivimed Labs Europe Ltd | Date: 2012-05-21

A photochromic polymer comprising at least two photochromic moieties linked by a straight or branched chain polymer selected from the group consisting of a homo-polyester, a co-polyester, and a co-polyester-polyether.

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