Molecular design, characterization, and application of multiinformation dyes for optical chemical sensing: IV. Multiinformation dyes with extended spectral sensitivity in the near-infrared spectral range

Daniel Citterio, Takashi Kawada, Jun Yagi, Tomonori Ishigaki, Hideaki Hisamoto, Shin Ichi Sasaki, Koji Suzuki

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

In this paper, new "multiinformation dyes" (MIDs) with extended spectral sensitivity reporting on both changes in solvent polarity (solvatochromism) and in pH (halochromism) by changes in their visible absorption spectra, are presented. The merocyanine dyes 2,6-dibromo-4-[4-(1-dodecyl-4(1H)-pyridinylidene)-2-butenylidene]-2,5- cyclohexadien-1-one (KD-M301) and 2,6-dibromo-4-[4-(1-dodecyl-4(1H)-quinolinylidene)-2-butenylidene]-2,5- cyclohexadien-1-one (KD-M402) were designed, synthesized, and characterized regarding analytical applications. The spectral sensitivity for the MIDs was extended into the near-infrared (NIR) wavelength range (λmax = 800 nm in CHCl3 for KD-M402) and at the same time, the degree of solvent polarity-induced spectral shifts was strongly enhanced (Δλmax = 202 nm for KD-M402 between tetrahydrofuran (THF) and methanol), reaching similar values to the standard solvatochromic dye Dimroth-Reichardt's betaine on which the empirical ET(30) classification of solvent polarity is based. Compared to Dimroth-Reichardt's betaine dye, the molar absorption coefficient ε, is increased more than 10-fold (ε of KD-M402 in THF: 7.7 × 104 M-1 cm-1), allowing sensitive measurements at low concentrations of the dye. The dodecyl-substituted KD-M402 is suitable as a lipophilic pH indicator in ion-exchange type optical sensors (optodes) with optical detection in the near-infrared wavelength range.

Original languageEnglish
Pages (from-to)19-28
Number of pages10
JournalAnalytica Chimica Acta
Volume482
Issue number1
DOIs
Publication statusPublished - 2003 Apr 10

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Keywords

  • Ion optode
  • Near-infrared
  • Optical sensor
  • Solvatochromism
  • pH indicator

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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