02516nas a2200289   4500008004100000022001400041245014300055210006900198260000800267300001400275490000600289520149400295653004001789653002001829653002001849653002001869653002801889653001901917100001701936700002601953700002201979700002402001700002102025700001802046700003002064856013202094       2019                        eng d  a2574-097000aAqueous-phase differentiation and speciation of Fe3+ and Fe2+ using water-stable photoluminescent lanthanide-based metal-organic framework0 aAqueousphase differentiation and speciation of Fe3 and Fe2 using  cAUG  a5169-51780 v23 a<p>Fe2+ is vital to O-2 transportation and photosynthesis regulated by oxidases and reductases. On the other hand, Fe3+ is detrimental due to its irreversible binding to O-2. Hence there is a need for selective identification of Fe3+ from aqueous systems in the presence of Fe2+. However, given their close chemical nature, it is not straightforward to differentiate them. Fe2+ and Fe3+ are typically sensed and differentiated using magnetic measurements, Mossbauer, X-ray absorption spectroscopy, or EXAFS, which are complex and equipment intensive techniques. In comparison, the fluorescence technique is advantageous in terms of time and accessibility. Although readily available lanthanide salts exhibit fluorescence, they are weak, and to serve as an optical probe, their luminescence has to be enhanced via ligand design. Hence we have designed a chromophoric ligand that can covalently bind to lanthanides and enhance its fluorescence intensity, and it binds selectively to Fe3+ through its nitrogen centers. It detects Fe3+ from low concentration (similar to 100 mu M) aqueous solutions, with fast response time (&lt;1 min) and with a detection limit of 3.6 ppm. Importantly, the Fe3+ adsorbed MOF can be readily reactivated for the next cycle by merely washing with an aqueous ascorbic acid solution and can be used for multiple cycles without any appreciable loss in activity. This makes the Ln-MOF an environmentally benign, cost-effective, scalable, and recyclable probe.</p>
10aFe3+ differentiation and speciation10aflexible ligand10afluorescent MOF10airon speciation10aMetal-organic framework10awater sorption1 aMaity, Rahul1 aChakraborty, Debanjan1 aNandi, Shyamapada1 aYadav, Ankit, Kumar1 aMullangi, Dinesh1 aVinod, C., P.1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/aqueous-phase-differentiation-and-speciation-fe3-and-fe2-using-water-stable-photoluminescent