Fluorenylidene bridged cyclotriphosphazenes: ‘turn-off’ fluorescence probe for Cu2+ and Fe3+ ions

Abstract

A first series of the 4,4'-(9-fluorenylidene)diphenol (), () and 4,4'-(9-fluorenylidene)dianiline (), () bridged cyclotriphosphazene derivatives (, ) were synthesized by nucleophilic SN2(P) and SN1(P) reactions, respectively. The structural investigations of the compounds were verified by elemental analyses, mass spectrometry, UV-vis, FT-IR, (1)H and (31)P NMR techniques, X-ray crystallography (for , , ) and fluorescence spectroscopy. The metal sensing properties of novel bridged cyclotriphosphazene derivatives were also examined by fluorescence spectroscopy. These complexes showed high selectivity for Cu(2+) and Fe(3+) ions in solution.

Regiochemical Control in the Substitution Reactions of Cyclotriphosphazene Derivatives with Secondary Amines

“…Nucleophilic substitution reactions leading to significant structure and property variations are central to cyclophosphazene chemistry. − In most of the degrees of substitution of the cyclophosphazene, the question of geminal versus non-geminal replacement patterns arises. ,,− This in turn has led to a search for models to predict these regio- and stereochemical outcomes. , The reaction patterns observed when the nucleophile is an amine have been the most intensively investigated systems. − The reactions of N 3 P 3 Cl 6 with primary amines lead to both geminal and non-geminal products depending on the steric and electronic effects of the amine as well as the nature of the incoming group. ,, In these systems, there are two competing mechanistic pathways with the bimolecular path providing the non-geminal product and a dissociative process giving the geminal product. However, most secondary amines, with the exception of aziridine, follow a predominantly non-geminal path, and these reactions are generally stereo- and regioselective with the trans non-geminal isomer as the major product.…”

Silver(I) coordination polymers assembled from flexible cyclotriphosphazene ligand: structures, topologies and investigation of the counteranion effects

“…Cyclophosphazenes are among the most prominent examples of inorganic N-heterocyclic ligands in basic and applied science (Mark et al, 1992;Andrianov, 2009;Gleria & De Jaeger, 2004;Rekha et al, 2014;Davarcı et al, 2013;Alidag ı et al, 2013;Ç oşut, 2014;Ç iftçi et al, 2013). Halocyclophosphazenes, formulated as [N PX 2 ] n (X = Cl or F; n = 3, 4), are good starting materials in the preparation of multisite coordination ligands because of easy substitution of their reactive P-X bonds with the appropriate substituent groups such as pyridyloxy, pyridylamin, carboxylate, pyrazolyl and phenanthroline (Chandrasekhar et al, 2002(Chandrasekhar et al, , 2007(Chandrasekhar et al, , 2012Chandrasekhar & Nagendran, 2001;Byun et al, 1996;Ainscough et al, 2003;Ainscough Brodie, Jameson & Otter, 2007Li et al, , 2014Yu et al, 2013).…”

Novel Coumarin Substituted Water Soluble Cyclophosphazenes as “Turn-Off” Type Fluorescence Chemosensors for Detection of Fe3+ ions in Aqueous Media

“…When BR^is the halogen, it can be replaced with ease by alkoxy, aryloxy or amino groups via nucleophilic substitution reactions [1][2][3][4][5][6]. Hexachlorocyclotriphosphazene, trimer, N 3 P 3 Cl 6 , (1) or octachlorocyclotetraphosphazene, tetramer, N 4 P 4 Cl 8 (2) namely cyclophosphazenes are a kind of phosphazene compounds that they show many special characteristics. Cyclotriphosphazenes can be easily functionalized on the phosphorus atoms, thus giving rise to a wide variety of substituted molecules [7][8][9][10][11][12].…”