Fluorescence Properties of Some Triazene Polyacrylates for Possible Sensor Applications

Abstract

We report here a first study on the capacity of the triazene chromophore attached to a polymeric backbone to present fluorescence properties. The sensing ability of two triazene copolymers poly[1-(phenyl)-3-(2 acryloyloxyethyl)-3-methyl triazene-1-co-methyl methacrylate] (TCP-1) and poly[1-(paramethoxy-phenyl)-3-(2 acryloyloxyethyl)-3-methyl triazene-1-co-methyl methacrylate] (TCP-2) in dimethylformamide (DMF) has been investigated by fluorescence spectroscopy in tandem with a quenching experiments using a variety of metal ions (Fe 3þ , Fe 2 , Cu 2þ and Cu þ ), which suggests that these triazene polymers could find practical applications for detection of metal ions. The emission spectra exhibited strong fluorescence emissions at 375 nm (TCP-1) and 410 nm (TCP-2) respectively, while the ability of Fe 3þ , Fe 2þ , Cu 2þ and Cu þ to quench the fluorescence of the triazene fluorophore has been explained on the basis of energy transfer processes involving the triazene excited state and the metal ion. The corresponding Stern-Volmer representations for all fluorescence emission spectra were also described.KEY WORDS: Polyacrylates / Fluorescence / Quenching / Sensor / Fluorescence spectroscopy and its applications in biochemical, medical, and chemical research have improved rapidly during the past decade.1 The increased interest on fluorescence emission appears to be the consequence of numerous developments and the fast appearance of new fluorescence methods in explaining physical and life sciences research. Based on sensitivity, selectivity and non-destructive characteristics, fluorescence spectroscopy can evidence various photophysical properties like fluorescence intensity, 1 emission maximum, 2 anisotropy, excimer or exciplex formation, 3 etc., whereas any variation caused by connecting or interacting with special external species (for instance, metal ions) could be used for sensing purposes. 4 In fact, the fluorescent sensors can offer several distinct advantages in terms of sensitivity, selectivity, response time and local observation. In the case of selective fluorescence sensors for cation detection, the scientists made considerable efforts for the development of these kinds of systems.As a general characteristic, fluorescence quenching refers to any process which undergoes emission intensity changes of a given molecule. Fluorescence response can be generated by a variety of mechanisms, including excited state reactions, energy transfer, complex formation, and collision quenching, 5,6 while photoinduced electron transfer and electronic energy transfer are considered the two main deactivation pathway responsible for an efficient fluorescence inhibition.Our group has specially focused on designing and fabricating a diversity of (co)polymers bearing different fluorophores such as pyrene, 7,8 dansyl, 9 stilbene 10,11 or anthracene 12 characterized through high quantum yields and good extinction coefficients, making them attractive components of biological and chemical sensors.

Assessment of the biological potential of diaryltriazene-derived triazene compounds

“…In industry, they can be used as chemical and biological reagents 13,14 and in organic synthesis [15][16][17] . The pharmaceutical industry has invested in studies on action against microorganisms 18,19 , functioning as appetite reducers 20,21 , anticancer agents [22][23][24][25][26] such as melanoma-specific 25 and primary brain tumors 28 therapeutics, fluorescence sensing agents 29 , mutagenic factors 12 , and having diabetic, anti-inflammatory, and antioxidant 27 activities; triazenes also exhibit biological and environmental activities 6,[30][31][32][33] .…”

Research Progress of Organic Polymer Fluorescence Sensor

“…1.2 基于聚合反应的聚合物传感器 利用传统的聚合反应, 特别是烯烃之间的加聚反 应, 也能直接制备有机聚合物荧光传感器 [66] , 并且有多 种应用 [67] , 特别是检测水溶液中的金属离子 [68] . 例如, Garcia 课题组 [69] 多功能荧光探针的设计、合成与应用日益受到重 视 [70] , 多金属离子探针的开发不断被报道 [71] , 基于不同 功能烯烃单体制备此目标的有机聚合物荧光传感器也 是可能的 [72] . 例如, 耿同谋课题组 [73] [75] .…”

Preparation of amphiphilic block copolymer containing triazene moieties and fluorescence study

“…From this experiment, it is obvious that the triazene moiety (>N−N=N−) is responsible for emission maximum. 12…”

“…In the literature, there are only few reports in relation to the quality of the triazene derivatives to act as fluorophores and especially, as chemosensors in the detection of ionic metals. 12,13,46 As a continuation of our work concerning the photochemical performance of some triazene polymers in the development of sensors for metal cations, we investigated some photophysical aspects of the triazene containing block copolymer in DMF solutions and in thin films. When excited at 320 nm, the PAA-b-(PDA-co-PUMA-T) solution emits a blue fluorescence with well-defined maximum positioned around 400 nm, whereas the maximum of the diblock copolymer in thin film is blue shifted with 25 nm (λ em = 375 nm).…”

“…[8][9][10][11] Moreover, in recent publications, the important attribute of the triazene copolymers to emit a strong fluorescence with a maximum around 400 nm was confirmed, feature of interest in chemosensor applications for the detection of some metal ions. 12,13 Meanwhile, the modern developments in reversible addition-fragmentation chain transfer (RAFT) polymerization have proved that this is one of the most versatile methods of controlled radical polymerization, successfully employed in preparing complex macromolecular architectures such as linear block copolymers, star and brush polymers, dendrimers. [14][15][16] Usually, RAFT polymerization is a living polymerization that yields polymers with a low polydispersity index and a predetermined molecular weight 16 and facilitates the controlled polymerization of a wide range of nonfunctional monomers under a great variability of experimental conditions.…”