Air-Stable N,N′-Dihydroporphycene: A Quinoxaline-Fused Tetrapyrrolic Macrocycle That Detects Fluoride Anion via Deprotonation

Abstract

An air-stable N,N′-dihydroporphycene, the twoelectron reduced form of porphycene, possessing two quinoxaline moieties fused at meso positions, was prepared and characterized. Nuclear magnetic resonance (NMR) and ultraviolet−visible light (UV-vis) spectroscopic studies and single-crystal X-ray diffraction analyses support its formulation as a nonaromatic species. Upon treatment with tetrabutylammonium fluoride (TBAF) in chloroform, a color change is produced that is consistent with deprotonation. Selective detection of this anion is readily achieved.Letter pubs.acs.org/OrgLett

Advances in fluorescent and colorimetric sensors for anionic species

“…Although the formation of hydrogen bonds is still one of the main strategies used for the development of anion optical sensors, the detectable changes of many systems are triggered by the deprotonation of sensors by basic anions such as fluoride or cyanide [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Ureas, thioureas, amides and sulfonamides are still the most commonly used binding motifs based on hydrogen bonds.…”

Quinoxaline-fused octaphyrin(2.0.0.0.2.0.0.0). A rudimentary chemosensor

“…Either the receptor interacts with the fluoride anion via hydrogen bonds, 21 or, alternatively, the fluoride anion acts to deprotonate one or more acidic protons from the receptor to generate bifluoride (HF 2 À ). 15,22 Both modes could lead to changes in the electronic structure of the sensor giving rise to spectroscopic differences. 1 H and 19 F NMR spectral analyses of samples treated with TBAF in CDCl 3 revealed signals corresponding to the bifluoride anion in the 16-17 ppm spectral region at both low and room temperature (cf.…”

“…These angles are significantly less than those of the reported N,N 0 -dihydroporphycene (891 and 411, respectively). 15 This marked difference might reflect the presence of unsubstituted pyrrole rings and the ''flippedover'' nature of the substituted pyrrole rings that comprise the central portion of the tetrapyrrolic fragments. Bond lengths between neighbouring pyrrole rings are in the range of 1.339-1.417 Å (C-C bond average = 1.392 Å).…”

Polyoxa- and Polyazamacrocycles Incorporating 6,7-Diaminoquinoxaline Moiety: Synthesis and Application as Tunable Optical pH-Indicators in Aqueous Solution

“…A combination of the quinoxaline fragment and macrocyclic receptor unit in several cases was shown to be efficient for the synthesis of sensing molecules. Thus, a series of quinoxaline-containing derivatives of calixarenes [ 41 , 42 , 43 ] and porphyrinoid-based macrocycles with quinoxaline groups [ 44 ] were described as anion-sensing chemosensors. Substituted quinoxalines containing macrocyclic moieties ( MC ) were reported ( Figure 1 ), allowing the detection of Hg(II) cations ( MC1 ) [ 45 ] and acetate anions ( MC2 ) [ 46 ].…”