Synthesis of Large Macrocyclic Azacalix[n]pyridines (n = 6 − 9) and Their Complexation with Fullerenes C₆₀ and C₇₀

Abstract

Large methylazacalix[n]pyridines (n = 6-9) were synthesized effectively from the Pd-catalyzed macrocyclic fragment coupling reactions between alpha,omega-dibrominated and alpha,omega-diaminated linear oligomers. As macrocyclic host molecules, they formed a 1:1 complex with fullerenes C(60) and C(70) with association constants ranging from 3 x 10(4) to 1 x 10(5) M(-1).

Receptors for Pristine Fullerenes Based on Concave–Convex π–πInteractions

“…In this context, host molecules composed of triarylamines should exhibit high affinities for fullerenes in comparison with the corresponding phenol-based receptors. Actually, the K SV values of a dendrimer 19 [36], azacalix [3]arene [3]pyridine 20 [37], and azacalix[n]pyridine 21 (n ¼ 4-9) [38] are considerably high (K SV for 19ÁC 60 ¼ 180000 AE 80000 Â 10 5 M À1 , K SV for 20ÁC 60 ¼ 70680 AE 2060 M À1 , and K SV for 20ÁC 70 ¼ 136620 AE 3770 M À1 ) (Figure 3.9). The participation of additional attractive CT interaction should play an important role in the complexation.…”

A macrocycle-assisted nanoparticlization process for bulk Ag2S

“…Considering the high efficiency of Py[6] (composed of six 1,3-pyridine rings bridged by six N–CH 3 moieties) 14 in our previous synthesis of a silver ethynediide cluster-encapsulated supramolecular capsule, 13 b we firstly attempted to utilize this macrocyclic ligand to dissolve Ag 2 S solid. When Ag 2 S solid was added to a methanol solution of AgCF 3 SO 3 (0.2 M), no obvious color change of the solution was observed.…”

“…1a). A typical downfield shift of these peaks relative to neat Py[6] (7.46 ppm for pyridyl γ-protons) 14 suggested the occurrence of coordination between Py[6] and silver ions. Furthermore, diffusion ordered spectroscopy (DOSY) exhibited two diffusion bands (Fig.…”

Recognition of amino acids and anions by a Zn(II)-methylazacalix[4]pyridine complex

“…Heteroatom-bridged calix(hetero)aromatic compounds are an emerging generation of macrocyclic host molecules [35][36][37][38][39][40][41][42][43][44][45][46][47][48] . The introduction of hetero atoms, especially nitrogen atoms, on the bridges results in the formation of different conformations and cavities, owning to the fact that bridging nitrogen atoms can adopt sp 2 or sp 3 or both electronic configurations and can form various degrees of conjugations with the adjacent aromatic rings [38][39][40][41][42][43]48] .…”

“…The introduction of hetero atoms, especially nitrogen atoms, on the bridges results in the formation of different conformations and cavities, owning to the fact that bridging nitrogen atoms can adopt sp 2 or sp 3 or both electronic configurations and can form various degrees of conjugations with the adjacent aromatic rings [38][39][40][41][42][43]48] . More importantly, when they interact with guest, the heteroatom-bridged calix(hetero)aromatic compounds can self regulate their conformations to best fit the guest, which enables their good recognition to both neutral molecules, such as diols, fullerenes, and metal cations [39][40][41]48] .…”