Novel structurally tuned DAMN receptor for "in situ" diagnosis of bicarbonate in environmental waters.

A new diaminomalenonitrile (DAMN) based charge transfer (CT) chromophore has been designed and synthesized. The receptor demonstrates highly specific and prompt bicarbonate anion (HCO3(-)) sensing in aqueous solution. Interaction with HCO3(-) triggers facile CT across the system, and enables the in situ recognition of water soluble carbonates. The recognition allows us to obtain qualitative as well as quantitative information from aqueous media. The inimitable potential of the receptor was further utilized for monitoring bicarbonate in a range of environmental waters.

Dual-mode chemodosimetric response of dibromo-BODIPY with anions.

Aromatic nucleophilic substitution (Ar-SN) reaction of 3,5-dibromopentafluorophenyl-BODIPY has been explored as a remarkable basis for selective discrimination of anions. The efficient and characteristic ability of anions to modulate the absorption and emission properties of the dye provides an instantaneous distinction through dual-modes. For the first time, a novel platform to achieve dual-modal and promising recognition with discrimination of a series of anions differing in the nucleophilic atoms (F, O, C and N) has been taken into consideration. The behaviour of various anions with dibromo-BODIPY and vivid signal transduction has been fully established with absorption and emission spectroscopy. In addition to this, recognition events have been unambiguously characterized by (1)H, (19)F-NMR and single-crystal XRD.

Reusable and specific proton transfer signalling by inorganic cyanide in solution and solid phase.

A highly specific cyanide mediated proton transfer signalling (PTS) is exhibited by a simple diaminomalenonitrile (DAMN) derivative 1. By virtue of the functional groups on it, the chromophore offered a rigid anchoring on a silica surface via a simple dip method, while retaining the recognition behaviour. The PTS triggered a prompt dual-modal display i.e., chromogenic and fluorogenic. The signal readout can be visualized even in micromolar concentrations. It is noteworthy that PTS can be reversed in both solution and solid phases. The remarkable sensitivity of 1 to detect CN(-) from the solution and solid phase envisages a pivotal step towards field-usable sensing.

A selective fluoride sensor and a digital processor with "Write-Read-Erase-Read" behaviour.

An easy-to-synthesize Schiff base as a selective and colorimetric fluoride sensor via modulation of intramolecular charge transfer (ICT) has been demonstrated. A typical dual-ion binding property along with its distinct reversibility has been explored for YES, NOR and INH logic functions and a potential "Write-Read-Erase-Read" mimic.

Aliphatic amine discrimination by pentafluorophenyl dibromo BODIPY.

Two new fluorescent BODIPY dyes have been designed and synthesized. They dyes differ in their meso substituents, which have different electronic properties. Their selective reactivity towards an Ar-S(N)2 reaction has been explored as a potential basis for colorimetric and fluorescent discrimination of primary, secondary and tertiary aliphatic amines. This dual-mode, instantaneous recognition event is unprecedented.

Exclusive fluoride ion recognition and fluorescence "turn-on" response with a label-free DMN Schiff base.

A label-free DMN Schiff base (4) has been explored as a highly selective and sensitive fluoride ion receptor. Fluoride-induced deprotonation results in a charge transfer (CT) transition red shifted with a fluorescence 'turn-on'. Anion selectivity can be tuned by the electron push-pull property of substituents at the phenyl para-position. Selectivity for F(-) is attributed to the suitable acidity of -NH2.