Structure–reactivity correlation in selective colorimetric detection of cyanide in solid, organic and aqueous phases using quinone based chemodosimeters

Abstract

The five new colorimetric chemodosimeters sense cyanide selectively and sensitively in aqueous and organic media via a nucleophilic addition mechanism exhibiting quantitative structure–reactivity correlation.

Regioselective addition of DDQ on a quinoid ring: an entry into chiral zwitterionic bridging ligands

“…The newly formed C-C bond involves one of the two DDQ carbon atoms bearing a cyano group as already observed when such addition occurred between DDQ and various nucleophilic carbon atoms of, for example, silyl enol ethers, 14 enaminones 15 or indoles. 16 If the C=O bond of the DDQ moiety adjacent to the quaternary carbon atom remains a double bond with a length of 1.203(8) Å, the formation of the zwitterion 11a is resulting from a proton transfer from the two starting components confirmed by the new C-OH single bond length of 1.334(8) Å. The crystal packing of the racemic 11a revealed that each enantiomer of 11a is interacting with the other one thanks to a π-π interaction producing a "tête-bêche" arrangement ( Figure 4b).…”

“…-3 )= 344 (25.0), 356 (25.9), 478 nm (1.4); HRMS (ESI-TOF): calcd. for C 16 4, 168.9, 155.0, 154.6, 143.4, 134.9, 115.6, 115.4, 106.3, 87.1, 82.5, 58.7, 47.0, 45.7…”

Facile Synthesis of Isoindigo Derivatives from 3‐Indolyl‐2‐Oxindoles with DDQ

“…Instead, meisoindigo 2a was formed in low yield (5–10%). When we carried out the reaction of 1a′ and DDQ (2.0 equiv) in the presence of TFA (20 mol%) in refluxing toluene for 18 h, the yield of 2a increased to 31%, as shown in Scheme . However, the reaction is less atom‐economic due to loss of valuable one molecule of indole.…”