Effect of metal oxidation state on FRET: a Cu(i) silent but selectively Cu(ii) responsive fluorescent reporter and its bioimaging applications

A new structurally characterized cell permeable rhodamine-cinnamaldehyde hybrid (HL) behaves as a Cu(ii) ions selective chemosensor through FRET process which depends on +2 state of copper ion exclusively.

A napthelene–pyrazol conjugate: Al(iii) ion-selective blue shifting chemosensor applicable as biomarker in aqueous solution

A new crystallographically characterized napthelene–pyrazol conjugate acts as an Al(III) ion selective chemosensor in 100 mM HEPES buffer (water–DMSO 5 : 1, v/v) at biological pH. It is an efficient biomarker in detecting Al(III) ions in living cells.

A FRET-based ‘off–on’ molecular switch: an effective design strategy for the selective detection of nanomolar Al3+ ions in aqueous media

A FRET-based ratiometric chemosensor (L1) is highly selective for Al³⁺ ions (as low as 6.19 × 10⁻⁹ M) and could be used to acquire images of Al³⁺ ions in living cells.

A quinazoline derivative as quick-response red-shifted reporter for nanomolar Al3+and applicable to living cell staining

A newly designed and structurally characterized non-cytotoxic quinazoline based ratiometric chemosensor (L) selectively detects Al³⁺ions upto 1.48 nM through ICT and CHEF processes in water–DMSO (9 : 1, v/v) and it is also applicable in living cell staining.

Development of a rhodamine–benzimidazol hybrid derivative as a novel FRET based chemosensor selective for trace level water

A newly designed FRET-based rhodamine–benzimidazol hybrid molecule has been developed as a dual channel chemosensor for the detection of trace level water in both protic and aprotic organic solvents.

A simple coumarin as a turn-on fluorescence sensor for Al(iii) ions

A simple non-Schiff's base type molecule serves as a selective chemosensor for Al³⁺ based on the chelation-enhanced fluorescence (CHEF) effect.

A water soluble FRET-based ratiometric chemosensor for Hg(ii) and S2−applicable in living cell staining

A new water soluble rhodamine-based ratiometric dual ‘off–on–off’ probe can selectively detect Hg²⁺ions in ppb level through time dependent FRET process with reversibility in presence of S²⁻anions.

Development of a cell permeable ratiometric chemosensor and biomarker for hydrogen sulphate ions in aqueous solution

A newly designed benzimidazol-based water soluble ratiometric chemosensor selective for HSO₄⁻ ions behaves as an efficient biomarker for the detection of the distribution of HSO₄⁻ ions in living cells in HEPES buffer (1 mM; water : ethanol (v/v), 98 : 2).

A water soluble Al3+ selective colorimetric and fluorescent turn-on chemosensor and its application in living cell imaging

An efficient water soluble fluorescent Al(3+) receptor, 1-[[(2-furanylmethyl)imino]methyl]-2-naphthol (1-H) was synthesized and characterized by physico-chemical and spectroscopic tools along with single crystal X-ray crystallography. High selectivity and affinity of 1-H towards Al(3+) in HEPES buffer (DMSO/water: 1/100) of pH 7.4 at 25 °C showed it to be suitable for detection of intracellular Al(3+) by fluorescence microscopy. Metal ions, viz. alkali (Na(+), K(+)), alkaline earth (Mg(2+), Ca(2+)), and transition-metal ions (Ni(2+), Zn(2+), Cd(2+), Co(2+), Cu(2+), Fe(3+), Cr(3+/6+), Hg(2+)) and Pb(2+), Ag(+) did not interfere. The lowest detection limit for Al(3+) was calculated to be 6.03 × 10(-7) M in 100 mM HEPES buffer (DMSO/water: 1/100). Theoretical calculations have also been included in support of the configuration of the probe-aluminium complex.

A ratiometric fluorescent chemosensor for iron: discrimination of Fe2+ and Fe3+ and living cell application

A newly designed probe, 6-thiophen-2-yl-5,6-dihydrobenzo[4,5]imidazo-[1,2-c] quinazoline (HL(1)) behaves as a highly selective ratiometric fluorescent sensor for Fe(2+) at pH 4.0-5.0 and Fe(3+) at pH 6.5-8.0 in acetonitrile-HEPES buffer (1/4) (v/v) medium. A decrease in fluorescence at 412 nm and increase in fluorescence at 472 nm with an isoemissive point at 436 nm with the addition of Fe(2+) salt solution is due to the formation of mononuclear Fe(2+) complex [Fe(II)(HL)(ClO(4))(2)(CH(3)CN)(2)] (1) in acetonitrile-HEPES buffer (100 mM, 1/4, v/v) at pH 4.5 and a decrease in fluorescence at 412 nm and increase in fluorescence at 482 nm with an isoemissive point at 445 nm during titration by Fe(3+) salt due to the formation of binary Fe(3+) complex, [Fe(III)(L)(2)(ClO(4))(H(2)O)] (2) with co-solvent at biological pH 7.4 have been established. Binding constants (K(a)) in the solution state were calculated to be 3.88 × 10(5) M(-1) for Fe(2+) and 0.21 × 10(3) M(-1/2) for Fe(3+) and ratiometric detection limits for Fe(2+) and Fe(3+) were found to be 2.0 μM and 3.5 μM, respectively. The probe is a "naked eye" chemosensor for two states of iron. Theoretical calculations were studied to establish the configurations of probe-iron complexes. The sensor is efficient for detecting Fe(3+)in vitro by developing a good image of the biological organelles.