The Cucurbit[n]uril Family

Abstract

For Abstract see ChemInform Abstract in Full Text.

Threading the Needle: Fluorescent Poly-pseudo-rotaxanes for Size-Exclusion Sensing

“…28,29 The strength of these interactions along with the size of the individual cucurbit[n]urils is expected to control the extent of threading onto the PPyV backbone ( Fig. 1).…”

“…Alternatively protons located at the portal of the CB[n] undergo a downfield shift as they experience a deshielding effect from the carbonyl groups surrounding the cavity opening. 28,29 The 1 H NMR spectrum of PPyV as a function of increasing CB[n] concentration is shown in Fig. 2a.…”

“…The macrocycles chosen for this work are a series of highly symmetrical molecules known as cucurbit[n]urils (CB[n]), which are known to bind protonated nitrogen heterocycles and also have reasonable water solubility. 28 In cucurbit[n]urils glycoluril units are arranged such that the carbonyl dipoles define portals to an interior hydrophobic cavity. 29 CB[n]s exhibit selective binding of both neutral and positively charged guest species, 28,29 and can also discriminate between a range of aliphatic and aromatic species.…”

“…28 In cucurbit[n]urils glycoluril units are arranged such that the carbonyl dipoles define portals to an interior hydrophobic cavity. 29 CB[n]s exhibit selective binding of both neutral and positively charged guest species, 28,29 and can also discriminate between a range of aliphatic and aromatic species. [30][31][32] Our interest in threading CPs with CB[n]s is to exploit this discriminating binding with the sensitivity afforded by exciton migration to create a new fluorescence quenching and size-exclusion sensory platform.…”

Encapsulation of alkyl and aryl derivatives of quaternary ammonium cations within cucurbit[n]uril (n = 6,7) and their inverted diastereomers: density functional investigations

“…The number of glycouril units in cucucrbituril homologues renders varying size to their hydrophobic cavity while portal carbonyl groups on portals provide hydrophilic exterior to these macrocycles. The CB[n] macrocycles show efficient and selective binding toward simple gaseous molecules [3], aliphatic/aromatic cations [16][17][18][19][20][21], metal complexes [22][23][24][25][26] Semiempirical quantum chemical investigations on novel tubular nanostructures of modified CB[n] combined with transition metals have been reported [37]. Furthermore density functional theory have been successfully applied to characterize the electronic structure and spectral features of CB [n] homologues and modified CB[n] hosts [37][38][39][40][41][42][43][44].…”