Polymethacrylate polymers with appended aluminum(III)-tetraphenylporphyrins: Synthesis, characterization and evaluation as macromolecular ionophores for electrochemical and optical fluoride sensors

Abstract

The synthesis and characterization of a novel polymethacylate polymer with covalently linked Al (III)-tetraphenylporphyrin (Al(III)-TPP) groups is reported. The new polymer is examined as a potential macromolecular ionophore for the preparation of polymeric membrane-based potentiometric and optical fluoride selective sensors. To prepare the polymer, an Al(III) porphyrin monomer modified with a methacrylate functionality is synthesized, allowing insertion into a polymethacrylate block copolymer (methyl methacrylate and decyl methacrylate) backbone. The resulting polymer can then be incorporated, along with appropriate additives, into conventional plasticized poly(vinyl chloride) films for testing electrochemical and optical fluoride response properties. The covalent attachment of the Al(III)-TPP ionophore to the copolymer matrix provides potentiometric sensors that exhibit significant selectivity for fluoride ion with extended lifetimes (compared to ion-selective membrane electrodes formulated with conventional free Al(III)-TPP structure). However, quite surprisingly, the attachment of the ionophore to the polymer does not eliminate the interaction of Al(III)-TPP structures to form dimeric species within the membrane phase in the presence of fluoride ion. Such interactions are confirmed by UV/visible spectroscopy of the blended polymeric films. Use of the new polymer-Al(III)-TPP conjugates to prepare optical fluoride sensors by co-incorporating a lipophilic pH indicator (4',5'-dibromofluorescein octadecyl ester; ETH7075) is also examined and the resulting optical sensing films are shown to exhibit excellent selectivity for fluoride, with the potential for prolonged operational lifetime.

Polymethacrylic zinc porphyrin: A new approach to chiral recognition

“…In fact, such attributes, besides the vital role played in biological processes, make these materials available to a wide range of practical applications in areas such as catalytic asymmetric synthesis [1][2][3], nonlinear optics [4,5], and molecular devices [6,7].…”

A comparative study on fabrication of Mn2+ selective polymeric membrane electrode and coated graphite electrode

“…However such materials are not available in abundance, which has made the development of ISE a slightly difficult job. Nevertheless in recent years some new groups of compounds such as Schiff bases [27][28][29], porphyrins [30,31], calixaranes [32,33], macrocyclic compounds [34,35] and other group of compounds [36,37] have been developed which have a coordinating cavity and due to which they tend to show high affinity for some particular metals and poor for others. Among these groups, Schiff bases are the item of choice, because it is easy to form them with varying cavity size.…”

Responses of Metalloporphyrin‐Based Ion‐Selective Electrodes to pH

“…The addition, however, induces the formation of cationic dimers [12,13], which may interfere with reliable potentiometry. The merits and demerits of this reaction were discussed [14], and the countermeasure, such as the use of picket fence-porphyrins and the immobilization of the carrier onto a polymer network, have been proposed [12,[15][16][17].…”