Langmuir–Blodgett films of a benzothiazolium dye containing a crown ether ring

Lednev, Igor K.; Petty, Micael C.

doi:10.1002/amo.860040306

Cited by 12 publications

(9 citation statements)

References 20 publications

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“…The short wavelength component is characteristic of H-aggregates formed upon compression. Indeed, as it is known, hemicyanine dyes have a strong trend to self-associate into various types of complexes such as dimers as well as H- and J-aggregates. − This H-aggregation starts at rather low pressures of 14–17 mN/m and becomes well pronounced at further compression to 30 mN/m (Figure ). The asymmetry of the absorption band of the compressed monolayer indicates that aggregation of the dye is accompanied by the splitting of its electronic spectrum, intensities, and widths of these two components being comparable.…”

Section: Resultsmentioning

confidence: 97%

Cation-Controlled Excimer Packing in Langmuir–Blodgett Films of Hemicyanine Amphiphilic Chromoionophores

et al. 2016

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Supramolecular structure of ultrathin films of hemicyanine dye bearing a crown ether group (CrHCR) was tuned by lateral pressure and investigated by means of compression isotherms, UV-vis and fluorescence spectroscopies, and X-ray reflectivity. Two different types of aggregation were revealed, depending on the absence or the presence of metal cations in the water subphase. While CrHCR forms at high surface pressures head-to-tail stacking aggregates on pure water, changing the subphase to a metal-cation-containing one leads to the appearance of well-defined excimers with head-to-head orientation. The structure of monolayers transferred onto solid supports by the Langmuir-Blodgett (LB) technique was examined by use of X-ray reflectivity measurements and molecular modeling. A model of cation-induced excimer formation in hemicyanine Langmuir monolayers is proposed. Finally, fluorescence emission properties of LB films of CrHCR can be managed by appropriate changes in the subphase composition, this last one determining the type of chromophore aggregation.

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Section: Resultsmentioning

confidence: 97%

Cation-Controlled Excimer Packing in Langmuir–Blodgett Films of Hemicyanine Amphiphilic Chromoionophores

et al. 2016

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“…In several works [24][25][26][27] the formation of a trilayer by the roll-over mechanism has been proposed, always linked with the development of a plateau in the isotherm. In our case, AFM images do not indicate that a homogeneous trilayer is formed, but only random distributed islands of several nm height are observed in the quasi plateau region.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Langmuir and Langmuir–Blodgett films of a thiomacrocyclic ionophore by surface pressure and AFM

Torrent‐Burgués¹,

Pla²,

Escriche³

et al. 2006

Journal of Colloid and Interface Science

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The new synthesized thiomacrocyclic ionophore 4-phenyl-4-sulfide-11-(1-oxodecyl)-1,7-dithia-11-aza-4-phosphacyclotetradecane has proven to form Langmuir and Langmuir-Blodgett (LB) films. This ionophore shows a large affinity for copper (II) ions. Then, the influence of the subphase composition on the surface pressure-area isotherms has been studied. The LB films have been observed by AFM and the effect of the subphase composition and the deposition surface pressure on the LB films is discussed. AFM image morphology has been correlated to the ionophore molecular structure. Surface pressure-area isotherms and AFM images show that the presence of copper(II) ions has an important role in the film structure.

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“…Scheme of Complex Formation in a Floating Monolayer. To take into account the possible formation of sandwich complexes and aggregates in a floating monolayer, a more detailed reaction scheme must be considered L + M -LM (3) ztL + (n -1)M ¿ L"M"_i (4) Km triL Am, where n,m = 2, 3, 4,... (5) where Am is an aggregate containing m BTC Equations 6 and 7 follow from this scheme: molecules.…”

Section: Resultsmentioning

confidence: 99%

Complex Formation of an Amphiphilic Benzothiazolium Styryl Chromoionophore with Metal Cations in a Monolayer at the Air-Water Interface

Lednev¹,

Petty²

1995

J. Phys. Chem.

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A condensed floating monolayer of an amphiphilic benzothiazolium styryl dye containing a 1,lO-dithia-18-crown-6 ether group has been found to complex with Ag+ and Hg2+ cations in acidic subphases. The efficiency of the processes was more than 2 orders of magnitude greater than expected for homogeneous solutions. This was attributed to the formation of L2M complexes (L = ligand; M = metal cation) at salt concentrations of to M. "Sandwich" complexes with composition L,M,-l ( n > 2 ) may form at higher salt concentrations. Surface pressure versus area isotherms measured on Ag+-containing subphases showed changes for Ag+ concentrations in the range lod7 to M. However, BTC Langmuir-Blodgett films built up from acidic subphases containing either AgC104 or Hg(C104)2 only exhibited hypsochromic shifts in their longwavelength absorption peaks for salt concentrations from to M.

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Langmuir–Blodgett films of a benzothiazolium dye containing a crown ether ring

Cited by 12 publications

References 20 publications

Cation-Controlled Excimer Packing in Langmuir–Blodgett Films of Hemicyanine Amphiphilic Chromoionophores

Cation-Controlled Excimer Packing in Langmuir–Blodgett Films of Hemicyanine Amphiphilic Chromoionophores

Characterization of Langmuir and Langmuir–Blodgett films of a thiomacrocyclic ionophore by surface pressure and AFM

Complex Formation of an Amphiphilic Benzothiazolium Styryl Chromoionophore with Metal Cations in a Monolayer at the Air-Water Interface

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