Improved guanidinium ion-selectivity by novel calix[4]arene and calix[6]arene receptor molecules on CHEMFETs

Calixarene-Based Molecules for Cation Recognition

“…The suitable cavity size and binding geometry contribute to the selectivity over alkali ions. Having excessive binding sites removed while retaining C3-symmetry, 23b has a higher selectivity in CHEMFETs (log K gu,M = -1.8 (K), -1.85 (Na), -1.8 (NH 4 ), -2.8(Ca), FIM) [123] and in transport across liquid membranes [124]. Another approach towards favourite gu + -binding (log K ass = 3.4) utilizes a 'cap' for rigidifying calix [6]arenes [125] or homotrioxacalix [3]arene [126], although in the first case it slows down the dissociation rate.…”

Synthesis of thymidine derivatives bearing aromatic oligoamides with rigidified backbone

“…The intramolecular hydrogen bonds are able to rigidify the conformation of oligoamide backbone, leading to the formation of macrocycles (Yuan et al , 2004a ) and foldamers (Yuan et al , 2004b ). Furthermore, the acyclic and cyclic oligoamides are able to form cavities that favorably recognize molecules, such as guanidine and arginine (Pedersen , 1967 ;Kyba et al , 1977 ;Lehn et al , 1979 ;Kremer et al , 1994 ;Takeshita et al , 1994 ;Schrader , 1998 ;Bell et al , 1999 ;Sanford et al , 2005 ;Schugand et al , 2005 ;Zheng et al , 2008 ;Yamato et al , 2009 ). We envision that the oligoamides could help functionalize thymidine for molecular specifi c recognition.…”

Density functional theory study of calix[4]arene‐N‐azacrown‐5, calix[4]arene‐N‐phenyl‐azacrown‐5, and their complexes with alkali‐metal cations: Na+, K+, and Rb+

“…Among the numerous "tailor made" ligands for a large variety of metal cations, crown-ether derivatives of calixarenes (calixcrowns) represent not only some of the earliest complexes 17 but also elegantly demonstrate the potential of these compounds. 18 Calixarenes find applications as ion carriers, [19][20][21][22] analytical sensors, 23-26 model structures for biomimetics research, [27][28][29][30] and tools for studying the stabilizing effects of intramolecular and intermolecular hydrogen bonding. [31][32][33][34][35][36] The conformational stability of substituted calix [4]arenes has been mainly attributed to hydrogen bonding, steric and electrostatic forces, guest complexation, and to a lesser degree solvent effects.…”