Dansyl-based fluorescent films prepared by chemical and electrochemical methods: cyclic voltammetry, afm and spectrofluorimetry characterization

Abstract

Filmes fluorescentes baseados em derivados de dansila foram preparados a partir de duas metodologias diferentes. Em uma delas, a superfície de um eletrodo de óxido de índio dopado com estanho (ITO) foi coberta com um filme de quitosana e o polímero foi posteriormente derivatizado com cloreto de dansila, enquanto que na outra metodologia, um filme de dansilglicina foi depositado eletroquimicamente sobre ITO. A técnica de microscopia de força atômica (AFM) foi usada para mapear a superfície dos filmes. A comparação das propriedades eletroquímicas, fotoquímicas e morfológicas destes filmes indicou que o filme de dansilglicina depositado eletroquimicamente sobre ITO apresentou resposta eletroquímica, nível de fluorescência mais intenso, maior rugosidade superficial e maior área superficial relativa em comparação com o seu homólogo quitosana-cloreto de dansila. Esse comportamento pode ser atribuído ao maior número de sítios ativos presentes na estrutura bem organizada do filme eletrodepositado em comparação com os filmes produzidos quimicamente.Dansyl-based fluorescent films were prepared by two different methods. In one of them, the surface of an indium tin oxide (ITO) electrode was coated with a film of chitosan and the polymer subsequently derivatized with dansyl chloride, whilst in the second method a film of dansylglycine was electrochemically deposited on the ITO surface. Atomic force microscopy (AFM) was employed to map the surfaces of the films. Comparison of the morphological, photochemical and electrochemical properties of these films indicated that the dansylglycine film electrodeposited on ITO exhibited electrochemical response, emitted a higher level of fluorescence, presented greater surface roughness and larger relative surface area in comparison with its dansyl chloridechitosan counterpart. This behavior can be attributed to the higher number of active sites present in the well-organized and rough structure of the electrodeposited film in comparison with the chemically produced films.Keywords: fluorescent films, chitosan, dansyl derivatives, atomic force microscopy IntroductionSurface immobilization of organic molecules on various solid supports to prepare thin films with desired properties has gained considerable research interest in the past few decades.1 This is because, on one hand, it can offer model systems to study surface-dependent phenomena like catalysis, 2 adhesion, 3 or wetting, 4 and, on the other hand, it plays a great role in the design and preparation of functionalized surface materials. 5,6 The photochemical, photophysical and electrochemical properties of these functional films offer a wide range of potential applications in nonlinear optics, 7 displays, 8,9 biomedicine and chemical sensors. 10Fluorescent films are of particular interest by virtue of their specific advantages regarding sensitivity and Silva et al. 1809 Vol. 22, No. 9, 2011 selectivity, once such films are reusable and are readily fabricated into devices. 6 Some special fluorophores, which may have two parts in the...

Synthesis, characterization, and Pb2+ ion sensing application of hexa‐armed dansyl end‐capped poly(ε‐caprolactone) star polymer with phosphazene core

“…12 It severely damages the central nervous and endocrine systems, as well as it causes digestive and cardiac problems. 24,25 Besides, fluorescence emission spectrum of dansyl fluorophore is very sensitive to polarity and pH changes in the analytic media. In this respect, fluorescence spectroscopic method has significant advantages regarding sensitivity, selectivity, and response time.…”

Fluorescent polymer nanofibers based on polycaprolactone and dansyl derivatives for development of latent fingerprints

“…It is well known that dansyl derivatives are fluorescent, showing greenish to yellow light emission in the range of 500-550 nm for the fluorophores solubilized in organic solvents, such as, CH 2 Cl 2 and CH 3 CN. 20,22,47,48 PCL is able to interact with the dansyl fluorophores through the formation of hydrogen bonding between the carbonyl group of PCL and the amine or carboxylic acid groups of DnsCad or DnsGly. 49,50 The maximum emission wavelength of the electrospun PCL/fluorophore is hypsochromically shifted compared with the fluorescence maximum of pristine fluorophores, suggesting that such blue-shift is due to the immobilization of the fluorophore within the PCL matrix, as observed by Mocanu et al 51 for the dansyl fluorophore immobilized in alginate and/or cyclodextrin and Zarybnicka et al 52 by applying fluorescent label in polymer nanofibers.…”

“…Our group have synthesized and characterized a series of fluorescent materials based on 1-(dimethylamino)-naphthalene-5-sulfonyl, also known as dansyl, derivatives aiming their application in optoelectronic devices. [20][21][22][23] The dansyl fluorophore exhibits intense absorption bands in the near UV region as well as strong fluorescence in the visible region with high emission quantum yields. 24 Such features, along with the synthetic versatility of the sulfonyl group, aroused considerable interest in preparation of fluorescent electrospun nanofibers for several applications.…”

Dansyl-modified carbon dots with dual-emission for pH sensing, Fe3+ ion detection and fluorescent ink

“…30 In addition, dansyl uorophore is sensitive to micro-environmental change attributed to intramolecular charge transfer (ICT) and easy to be introduced at the N-terminal of many compounds containing amino group. [31][32][33][34][35] These characteristics make dansyl uorophore a core structure in most uorescent sensors for detecting anions and cations. 36 There are some reports on the synthesis of FL sensors by graing dansyl uorophore with organic compounds, but such sensors need detect targets in organic reagents.…”