Synthesis, structure, fullerene-binding and resolution of C₃-symmetric cavitands with rigid and deep cavities

Abstract

An efficient palladium-catalyzed Suzuki-Miyaura coupling method involving the reaction between CTV-Br(3) and a variety of aryl and heteroaryl boronic acids in the presence of indolyl phosphane ligands has been developed. This reaction procedure provided a series of C(3)-symmetric aryl-extended rigid cavitands for the first time. X-ray crystal structure analysis revealed that the phenyl substituted cavitand 5a has much larger rim edges and cavity height. This macrocyclic host adopts a linear head-to-tail "hand-shake" self-inclusion arrangement in the crystalline state. The fluorescence of 5a was considerably quenched upon the addition of C(60), with a binding constant of 78,700 ± 2300 dm(3) mol(-1) and a 1:1 stoichiometry according to the Job's plot. The interaction of C(60) with 5a in the excited state is stronger than that with CTV, which could be attributed to more binding sites in the extended arms of 5a. Moreover, optically active C(3)-symmetric cavitands (+)- and (-)-6 were easily obtained with high efficiency through chemical resolution.

Synthesis of Cyclotriveratrylene–Phenylacetylene Derivatives and a Photophysical Investigation of Rigid Conjugated Cyclotriveratrylene Dendrimers

“…[8] This stimulated our curiosity to synthesize CTV derivatives with even larger rigid cavities. [10] Reac-ties, were also synthesized. Recently, we have reported the use of classical Suzuki-Miyaura coupling conditions with CTV-Br 3 in the presence of [Pd(PPh 3 ) 4 ] and anhydrous K 2 CO 3 .…”

“…Recently, we have reported the use of classical Suzuki-Miyaura coupling conditions with CTV-Br 3 in the presence of [Pd(PPh 3 ) 4 ] and anhydrous K 2 CO 3 . [10] Reac-ties, were also synthesized. The band gaps of 4k-m are 3.49, 3.49 and 3.45 eV, and the fluorescence quantum yields are 0.64, 0.78, 0.48 (2-aminopyridine as a standard and excited at 310 nm), respectively.…”

Rapid Access to Triarylated Cyclotriveratrylenes from Threefold Couplings of CTV‐I3 with Triarylbismuth Reagents

“…In many ways, the observed reactivity of this protocol is more efficient than other coupling methods. Previously reported coupling reactions that employ CTV‐Br 3 and arylboronic acids have required specialized indolyl phosphane ligands and longer reaction times (44–48 h) . The overall reactivity herein benefits from the employment of the triarylbismuth reagent, the advantages of which include: (i) only 1 equiv of triarylbismuth reagent for three iodo couplings is needed, (ii) the threefold couplings occur over a short reaction time (6 h), and (iii) the routinely used Pd catalytic system provides high cross‐coupling efficiency.…”

“…described the Sonogashira alkynylation of CTVs to prepare trialkynyl‐embedded CTVs that have promising photophysical properties . The same group also reported on the arylations of CTV‐Br 3 by using arylboronic acids under Pd‐catalyzed conditions . Significantly, these triarylations allow for the preparation of CTV derivatives with extended and deeper cavities.…”

“…Significantly, these triarylations allow for the preparation of CTV derivatives with extended and deeper cavities. Incidentally, there are not many coupling procedures available to access triarylated CTVs, and the reported coupling reactions that use arylboronic acids give moderate yields under indolyl phosphane ligand conditions and require long reaction times . Because of the importance of CTV derivatives, we set forth to explore new synthetic methods with the use of triarylbismuth reagents.…”