Controlling the Fluorescence Behavior of 1-Pyrenesulfonate by Cointercalation with a Surfactant in a Layered Double Hydroxide

Abstract

Zn-Al layered double hydroxides (LDHs) containing solely 1-pyrenesulfonate (PS) or 1-heptanesulfonate (HS) anions, or a mixture of the two with HS/PS molar ratios ranging between ca. 7.5 and 82, were prepared by the direct synthesis method and characterized by powder X-ray diffraction, thermal and elemental analyses, scanning electron microscopy, and FT-IR, FT-Raman, and (13)C{(1)H} CP MAS NMR spectroscopies. Well-ordered intercalates were obtained with basal spacings of 18.8 Å for the LDH intercalated by PS and 19.2-19.4 Å for the other materials containing HS. The photophysics of the solids, as well as the PS probe dissolved in water and common organic solvents (aiming to compare the behavior of the "isolated" molecule with that in the solid), were investigated by steady-state and time-resolved fluorescence techniques. The fluorescence spectra of the solid samples display two bands with maxima at 376 and 495 nm. Depending on the HS/PS ratios, the band intensity ratio (obtained at 375 and 520 nm) changes, reflecting different contributions from monomer and dimer species. The decays collected at 375 nm are biexponentials with a major component (∼97% of the total fluorescence) of 105 ns for the highest HS/PS ratio, which further loses importance with an increase in the PS content. When the decays are collected at 480 and 520 nm, the fits are triexponentials with a major component varying from 108 to 124 ns, attributed to an excimer. Steady-state and time-resolved measurements with PS in solution (ethanol, methanol, DMF, DMSO, and water) were also measured, and a comparison of the vibronic I1/I3 ratio and lifetimes in water (65 ns) with those in the LDHs indicates that the PS probe in the cointercalated LDHs is surrounded by the HS surfactant.

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

“…Costa et al prepared Zn−Al layered double hydroxides (LDHs) containing solely 1pyrenesulfonate (PS) or 1-heptanesulfonate (HS) anions, or a mixture of the two molecules with HS/PS molar ratios ranging between 7.5 to 8.2, by a direct synthesis method. 195 The obtained solids were characterized by different experimental techniques including FT-IR, FT-Raman, and 13 C{ 1 H} CPMAS NMR spectroscopy.…”

Tailoring Hybrid Layered Double Hydroxides for the Development of Innovative Applications

“…The cointercalation of photofunctional molecules with surfactants has also been widely reported as an efficient way to tune and control the molecular packing mode within the LDH interlayer, which is of critical importance when designing efficient optoelectronic and photofunctional materials (vide supra). The surfactant may provide a homogenous nonpolar microenvironment by minimizing molecule aggregation and self‐quenching phenomena . Cointercalation can be carried out either by performing an anion exchange or through a direct synthesis route at constant pH or using a nucleation/crystallization separation method.…”

“…In both cases, an aqueous mixture of the two molecular guests in a suitable molar ratio is used. A broad range of active species has been immobilized using such a strategy, like α‐naphthalene acetate, (sulforhodamine B, 4‐(4‐anilinophenylazo)benzenesulfonate, fluorescein, coumarin‐3‐carboxylate, (1‐anilinonaphthalene‐8‐sulfonate, 8‐hydroxypyrene‐1,3,6‐trisulfonate, 2‐phenylbenzimidazole‐5‐sulfonate, 1‐pyrenesulfonate, zinc phtalocyanine . Wei and co‐workers demonstrated that size matching between the surfactant and the functional molecule favors sample homogeneity and fluorescence performances .…”

Pyrene and nile red fluorescence probes for in‐situ study of polarity and viscosity of soil organic coatings implicated in soil water repellency

“…An outline of the basic photochemistry of pyrene is given in the Supporting information. For this work, the important features are: (a) pyrene monomer fluorescence shows a series of vibrational bands, the relative intensities of which vary with environment polarity (Kalayanasundaram & Thomas, 1977); and (b) the kinetics of pyrene excimer formation can be used to assess environment viscosity (Costa, Gomes, Pillinger, Goncalves, & Seixas de Melo, 2015;Glushko, Thaler, & Karp, 1981). Pyrene excimer formation has been widely studied in many different environments (Birks, Dyson, & Munro, 1963;Birks, Lumb, & Munro, 1964;Montalti, Credi, Prodi, & Gandolfi, 2006).…”