Association of indopolymethine cyanine cations with anions of sulfonephthalein and xanthene dyes in water

Abstract

A associação do corante catiônico indoeptametinocianina com vários corantes aniônicos (quatro sulfonaftaleínas e cinco xantinas) em solução aquosa foi investigada usando espectroscopia de absorção no visível. Os valores das constantes de associação estão na faixa de 10 4 a 7 × 10 7 mol -1 L. Em todos os casos, um efeito hipocrômico significativo foi observado para a banda de absorção do cátion (λ max = 737 nm). O mesmo foi observado para a interação do cátion indotrimetínio (λ max = 540 nm) com espécies aniônicas. Interações eletrostáticas, de Van der Waals e hidrofóbicas são identificadas como as forças que dirigem esta associação. A adição de surfatantes iônicos destrói os compostos de associação do corante, primeiramente devido à interação com os íons de corante com carga oposta. Este processo é acompanhado pela restauração dos espectros de absorção visível dos corantes aniônico e catiônico.The association of the cationic dye indoheptamethine cyanine with various anionic dyes (four sulfonephthaleins and five xanthenes) in aqueous solutions was detected using the Vis-spectroscopic method. The values of the association constants are within the range (10 4 to 7×10 7 mol -1 L). In all the cases a substantial hypochromic effect is observed for the Vis absorption band of the cation (λ max = 737 nm). The interaction of indotrimethinium cation (λ max = 540 nm) with anionic species manifests itself in analogous manner. Electrostatic, Van der Waals, and hydrophobic interactions are regarded as driving forces of the association. Addition of ionic surfactants destroys the dye associates, primarily due to interactions with the oppositely charged dye ions. This process is accompanied by the restoration of the initial Vis absorption bands of both the cationic and the anionic dye.

Heteroassociates of singly- and doubly-charged anions of alizarin red S with the pinacyanol cation

“…At the same time, unlike the listed phenolsulfophthalein de rivatives, AR contains no bromine atoms, which enhance the hydrophobicity of the anion and thus favor the en hancement of the cation anionic interactions. 1,4, 25 The probable structure of the associate (Ct + ) 2 •HAn 2-calculated by the AM1 semiempirical method 35,36 (calcu lation conditions: the Polak Ribiere convergence algo rithm; the convergence gradient of two successive itera tions not higher than 2 kJ mol -1 ) is presented in Fig. 4.…”

“…23 Specific features of calculations have been described pre viously. [24][25][26][27] The acidity in the medium was created by buffer solutions and the addition of HCl or NaOH. Additional experi ments showed that the components of the used buffer solutions exert no noticeable effect on the studied processes of heteroasso ciation.…”

Cation-Anionic Association of Organic Dyes in Aqueous Solutions: Structure and Properties of Associates

“…We have previously described examples of the application of quantum chemical methods for simulating the properties of individual ions of dyes and cation-anion associates [17][18][19][20]. A specific pH of the solution should be created to ensure the interaction of the cation Ct + with the anion HAn -(or An 2-) of the corresponding dyes (the acidity of the solution should be such as to provide admixture of other protolytic forms).…”

“…"dissimilar" associates, further in the text associates) more in detail. Some facts of cation-anionic interactions with organic dyes were considered earlier [17]. In this report, on the basis on the results of spectrophotometric measurements and quantum chemical simulations, we have analysed the cation-anion interaction leading to the formation of stoichiometric associates between single-charged cations (Ct [18] due to its spectral and protolytic properties.…”

Diagnostic Paper Chip for Reliable Quantitative Detection of Albumin using Retention Factor

“…진단은 요검사 시험지에 소변 (샘플)을 적신 후, TBPB의 색깔 변화를 분석하여 질병을 진단한다. pH 3.0의 요검사 시험지에 흡착된 TBPB는 짧은 컨쥬게이션 결합 길 이를 갖는 구조를 가진다 [6][7][8]. 이중 결합에 관여하는 파이 전자는 한 곳에 국한되지 않고, TBPB의 짧은 컨쥬게이션 결 합 사슬을 따라서 움직인다.…”