✍ Scribed by Xiaoyan Zheng; Xueye Wang; Keqi Shen; Nuanqing Wang; Yueming Peng
No coin nor oath required. For personal study only.
The chemically switchable actions well imitate the function of a “molecular syringe,” has been studied in theory using the 1,3‐alternate calix [4]arene bearing a nitrogen‐containing crown cap at one side and a bis(ethoxyethoxy) group at another side by the π‐basic calixtube as a pipette and the crown ring as a rubber cap. The model is characterized by geometry optimization using density functional theory (DFT) at B3LYP/6‐31G level. The obtained optimized structures are used to perform natural bond orbital (NBO) and frequency analysis. The electron‐donating heteroatoms: O and N offer lone pair electrons to the contacting RY* (1‐center Rydberg) or LP* (1‐center valence antibond lone pair) orbitals of K^+^, Ag^+^. The results indicate that when the nitrogen atom in the crown ring is protonated, K^+^ and Ag^+^ will be pushed out to the bis(ethoxyethoxy) side through a π‐basic calixtube. When the nitrogen·H^+^ in the crown ring is deprotonated, K^+^ and Ag^+^ are sucked back to the crown‐capped side again. In the course of the coordination, both the intermolecular electrostatic interactions and the cation‐π interactions between the metal ion and π‐orbitals of the two pairs facing inverted benzene rings play a significant role. It is believed that this prototype of a “molecular syringe” is a novel molecular architecture for the action of metal cations. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
📜 SIMILAR VOLUMES
Ditopic "hard"-"soft" metal binding-sites composed of four EtS(CH&NHCOCH20groups were designed for the iirst time on a calixl4larene pkform. N = 2 is too short to form a bimetallic complex whereas n = 6 is long enough to accept two metal ions. 1H NMR spectral studies established that although Cdz+ b