Chemosensor For Detection Of Ions Research Articles

Acridinedione as selective flouride ion chemosensor: a detailed spectroscopic and quantum mechanical investigation.

The use of small molecules as chemosensors for ion detection is rapidly gaining popularity by virtue of the advantages it offers over traditional ion sensing methods. Herein we have synthesized a series of acridine(1,8)diones (7a–7l) and explored them for their potential to act as chemosensors for the detection of various anions such as fluoride (F−), acetate (OAc−), bromide (Br−), iodide (I−), bisulfate (HSO4−), chlorate (ClO3−), perchlorate (ClO4−), cyanide (CN−), and thiocyanate (SCN−). Acridinediones were found to be highly selective chemosensors for fluoride ions only. To investigate in detail the mechanism of selective fluoride ion sensing, detailed spectroscopic studies were carried out using UV-visible, fluorescence and 1H NMR spectroscopy. Fluoride mediated (NH) proton abstraction of acridinedione was found to be responsible for the observed selective fluoride ion sensing. Quantum mechanical computational studies, using time dependent density functional theory (TDDFT) were also carried out, whereupon comparison of acridinedione interaction with fluoride and acetate ions explained the acridinedione selectivity for the detection of fluoride anions. Our results provide ample evidence and rationale for further modulation and exploration of acridinediones as non-invasive chemosensors for fluoride ion detection in a variety of sample types.

The importance of water exclusion: an effective design strategy for detection of Al3+ ions with high sensitivity

Incorporation of hydrophobic units in a chemosensor for detection of ions in aqueous media seems counterintuitive. However, this work demonstrates that a sensor designed by incorporating local hydrophobicity around a multidentate receptor to achieve desolvation of a strongly hydrated Al3+ ion results in efficient binding of the ion, and consequently elicits a strong fluorescence response. The simultaneous detection of Fe3+ in water was suppressed by using the differential behaviour of the sensor in a methanol–water mixture. The sensor shows a remarkable detection limit of 57 nM for Al3+ which is among one of the lowest reported so far.