Crystallographic, 1H NMR and CD studies of sterically strained thiourea anion receptors possessing two stereogenic centres

Abstract

The synthesis and structural characterisation of three chiral bis-naphthalene thiourea receptors (1-3) derived from (R)-(+)-1-(1-naphthyl)ethylamine and (S)-(À)-1-(1-naphthyl)ethylamine are reported along with spectroscopic studies to screen their potential as anion receptors/sensors. Their solid state structures were analysed by X-ray crystallography and their ability to bind anions such as acetate and phosphate in DMSO solution investigated by 1 H NMR, absorption, fluorescence and circular dichroism spectroscopy.Scheme 1 Synthesis of compounds 1-3.

On the role of DMSO-O(lone pair)⋯π(arene), DMSO-S(lone pair)⋯π(arene) and SO⋯π(arene) interactions in the crystal structures of dimethyl sulphoxide (DMSO) solvates

“…Five of the structures adopt motif III, where the DMSO-O atom is held in place by one (17 36 ), two (15, 34 16 35 and 19 38 ) and four (14 33 ) hydrogen bonds and where the DMSO-S(lp)⋯π(arene) interaction is considered intramolecular. Structure 16 35 is particularly notable as the DMSO-S(lp)⋯π(arene) interaction appears to be bifurcated (Fig. 6a).…”

Synthesis, photophysical and NMR evaluations of thiourea-based anion receptors possessing an acetamide moiety

“…For instance, the 1 H NMR spectrum (600 MHz, DMSO-d 6 ) for receptor 4 showed the presence of two broad resonances, one appearing at 9.98 ppm, assigned to one of the thiourea protons, while a second resonance, appearing at 9.94 ppm, corresponded to the second thiourea proton and the amide proton, respectively. In contrast, for 5, the thiourea protons appeared as a single broad signal at 10.06 ppm, while the amide proton resonated at 9.97 ppm.…”

“…Much effort has been devoted to the detection of anions due to the important roles they play in physiology, industry and in the environment (5). The recognition and sensing of anions using luminescent and colorimetric methods and, in particular, charge neutral receptors such as ureas and thioureas is of particular interest (6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Urea and thiourea groups have been widely used as anion receptor moieties as they are excellent hydrogen-bond donors (16)(17)(18)(19)(20)(21)(22)(23)(24).…”

Artificial Receptors for the Recognition of Phosphorylated Molecules

“…432 All three stereoisomers of 356 were investigated for their ability to bind acetate, dihydrogenphosphate, and fluoride (as the TBA salts) through a number of spectroscopic techniques. Binding constants were measured through 1 H NMR spectroscopy in wet (ca.…”