Young-A Son

Effect of reactive anionic agent on dyeing of cellulosic fibers with a Berberine colorant

Berberine, a natural cationic colorant, is the major component of Amur Cork tree extract. Due to ionic interactions, while it shows high exhaustion towards protein fibers such as wool and silk, it exhibits little substantivity onto cellulosic fibers. In this context, in order to apply the colorant to cellulosic fibers, the new approach of employing the anionic agent containing a dichloro-s-triazinyl reactive group was conducted. Berberine could display considerable substantivity towards anionic agent finished fibers. It was found that the anionic agent was covalently bonded to the cellulosic substrates by virtue of the covalent nature of its attachment to the fibers and also gave anionic sites to the substrate for electrostatic interaction with cationic Berberine. The effectiveness of the anionic agent in improving the exhaustion of Berberine on the cellulosic fibers was achieved.

Synthesis and property of solvatochromic fluorophore based on D-π-A molecular system: 2-{[3-Cyano-4-(N-ethyl-N-(2-hydroxyethyl)amino)styryl]-5,5-dimethylfuran-2(5H)-ylidene}malononitrile dye

2-[[3-Cyano-4-(N-ethyl-N-(2-hydroxyethyl)amino)styryl]-5,5-dimethylfuran-2(5H)-ylidene]malononitrile styryl dye was prepared by the condensation of 4-[(2-hydroxy-ethyl)-methyl-amino]-benzaldehyde (donor moiety) with 2-cyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (acceptor moiety). The corresponding design, synthesis and solvatochromic characteristics of the intramolecular charge-transfer (ICT) dye chromophore were discussed and determined. Optical properties such as absorption and fluorescence emission spectra were monitored in several solvent media with different polarity. In this determination, the prepared dye chromophore showed positive solvatochromism effect and the resulting solvatochromic characteristics were studied with semiempirical calculations. The energy potentials of this dye chromophore such as HOMO and LUMO values were calculated by computational simulation approaches using Material Studio 4.3. Furthermore, the functions as a molecular switching sensor with pH stimulation of alkali-acid addition were determined in DMSO, which was operated by deprotonation/protonation effects based on intramolecular charge-transfer system.

The application of heterobifunctional reactive dyes to nylon 6,6: process modifications to achieve high efficiencies

A heterobifunctional monochlorotriazine/vinyl sulphone (MCT/VS) reactive dye was applied to nylon 6,6 using various pH and temperature conditions. Optimum dye exhaustion and fixation were achieved at pH 4 and 98°C. The form in which the VS moiety was present during dyeing was examined by capillary electrophoresis. Preconversion of the dye to its VS form gave improved fixation and modified dyeing methods in which alkali additions were made at various points during the dyeing were used to achieve high dye fixation.

A highly selective and sensitive photoswitchable fluorescent probe for Hg2+ based on bisthienylethene-rhodamine 6G dyad and for live cells imaging.

A new photochromic diarylethene derivative bearing rhodamine 6G dimmer as a fluorescent molecular probe is designed and synthesized successfully. All the compounds are characterized by nuclear magnetic resonance and mass spectrometry. The bisthienylethene-rhodamine 6G dyad exhibit excellent phtochromism with reversibly color and fluorescence changes alternating irradiation with ultraviolet and visible light. Upon addition of Hg(2+), its color changes from colorless to red and its fluorescence is remarkably enhanced. Whereas other ions including K(+), Na(+), Ca(2+), Mg(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Mn(2+), Pb(2+), Ni(2+), Fe(3+), Al(3+), Cr(3+) and so on induce basically no spectral changes, which constitute a highly selective and sensitive photoswitchable fluorescent probe toward Hg(2+). Furthermore, by means of laser confocal scanning microscopy experiments, it is demonstrated that this probe can be applied for live cell imaging and monitoring Hg(2+) in living lung cancer cells with satisfying results, which shows its value of potential application in environmental and biological systems.

The aftertreatment of acid dyes on nylon 6,6 fibres. Part 1. 1 :2 pre-metallised acid dyes

Nylon 6,6 knitted fabric was dyed using a total of eight, commercial, 1:2 pre-metallised acid dyes and the dyed samples were aftertreated using three different commercial systems, namely a syntan, a syntan/cation process and a newly developed full backtan. When all dyeings were subjected to five consecutive ISO C061C2 wash tests, it was found that while all three aftertreatments imparted improved wash fastness, the newly developed backtanning system bestowed greatest wash fastness improvement towards repeated wash testing.

The photo- and electrophysical properties of curcumin in aqueous solution

An investigation of the photo- and electrophysical properties of curcumin (1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) revealed well-defined color changes upon the addition of Hg(2+) or OH(-). Curcumin exhibited high selectivity for Hg(2+) ions, as compared with Cu(2+), Fe(2+), Fe(3+), Zn(2+), Na(+) and Ni(2+) ions in DMSO/H(2)O (5:1, v/v) which was attributed to the formation of a 4:1 Hg(2+)-curcumin coordination complex. Spectral responses at lambda(max)=434nm revealed that curcumin can function as a NOR logic gate with OH(-) and Hg(2+) as input variables. The electrochromic properties of curcumin were studied using an ITO/curcumin-Bu(4)NClO(4)/ITO cell. The electrochromic cell colored red at 3V, but changed to yellow in open-circuit condition.

Synthesis and chemosensitivity of a new iminium salt toward a cyanide anion

A short, high-yielding route to pyranylidene Iminium (Imi) salts using a new pyrylium salt reaction between N,N-Dimethylformamide (DMF) and acetic anhydride is reported. The Imi salt-sensing behavior toward various anions has been investigated using UV-Visible spectroscopy. The Imi salt demonstrates high selectively for CN(-) when various other anions, such as CN(-), Cl(-), Br(-), I(-), SCN(-), ClO4(-), NO3(-), HSO4(-), PF6(-) and N3(-), are present because it is highly reactive towards nucleophiles. The selective detection of CN(-) with the Imi unit gave rise to a significant hypochromic shift in the CH3CN solution at λmax=444nm and 423nm and creation of new peak at 252nm. These studies indicated that CN(-) had high affinity toward Imi, forming a 1:1 complex; this observation agrees with the current understanding of these materials.

Synthesis of a novel pyrylium salt with chemoselectivity to a cyanide anion

The high-yield one-pot synthesis of a novel chemosensor based on a 4-methyl 2,6-diphenyl pyrylium trifluoromethanesulfonate (Pyr) salt that absorbs in the visible region is reported. The ability of pyr to sense various anions has been investigated using UV–visible spectroscopy and fluorescence spectroscopy. Pyr selectively detects CN− in competition with various other anions such as Cl− , Br− , I− , SCN− , ClO4− , NO3− , HSO4− and PF6− , due to its highly reactive nature towards nucleophiles. The selective detection of CN− with pyr gave rise to a significant hypochromic effect in CH3CN solution at λmax 387 and 446 nm, which are the absorption and fluorescence peaks, respectively. These studies indicated a high affinity of CN− for pyr, and forming a 1:1 ratio leads to cyano-enone derivative.

Design and synthesis of novel chemosensor based on rhodamine 6G monitoring heavy metal ions

One of the organic dye materials which has long been investigated is regarded as rhodamine 6G dye class. This dye material shows a special attractive intention with considerable interests due to the reason of its promising photochemical properties such as clear photoabsorption and emission characteristics. In this study, a novel fluorescent dye compound based on rhodamine 6G derivative was designed and synthesised through the reaction of rhodamine 6G hydrazide and indole-3-carboxaldehdyde. The resulting absorption and fluorescent emission spectra of this chemosensor were determined on the properties of sensing function towards Hg2+. This chemosensor 1 was also investigated on the binding ratio between chemosensor 1 towards Hg2+ using Jobs method. Related electron density and energy state of the dye compound were also characterised by computational calculations.

The fastness, to repeated washing, of reactive dyes and pre-metallised acid dyes on nylon 6,6

Standard depth dyeings were prepared using three, unsulfonated 1:2 pre-metallised acid dyes as well as three reactive dyes on knitted nylon 6,6 fabric and the fastness of the dyeings to 20 repeated wash tests was determined. In the case of the three pre-metallised acid dyes, while aftertreatment with a commercial syntan/cation system as well as a modification of this commercial system reduced both the rate and extent of dye loss during repeated washing, the extent of dye loss which occurred was not unsubstantial. In contrast, the dyeings obtained using the three commercial reactive dyes suffered considerably lower dye loss during repeated washing.