Jung, OS Kim, YJ Lee, YA Park, JK Chae, HK 2024-01-21T13:14:40Z 2024-01-21T13:14:40Z 2021-09-04 2000-10-18 0002-7863 https://pubs.kist.re.kr/handle/201004/141006 The rational construction and operation of an ideal helical spring has been investigated. The infinite helices, [Ag(Py2O)]X (Py2O = 3,3'-oxybispyridine; X- = NO3-, BF4-, ClO4-, and PF6-), have been constructed in high yield via cooperative effects of the skewed conformer of Py2O and the potential linear geometry of the N-Ag(I)-N bond. Crystallographic characterization reveals that the polymer framework is an ideal cationic cylindrical helix and that its counteranions are pinched in two columns inside the helix. The four anions have been exchanged fur each other in an aqueous solution without destruction of the helical skeleton. In particular; [Ag(Py2O)]NO3 prepared by the counteranion exchange can be isolated as crystals suitable for X-ray crystallography in water. The helical pitch is reversibly stretched via the counteranion exchange from 7.430(2) to 9.621(2) Angstrom, and is exactly proportional to the volume of the anion guests. This pitch-tuning is attributed to subtle change in the nonrigid dihedral angles between two pyridyl groups around O and Ag atoms that act as hinges within the helical subunit. Thermal analyses indicate that the helical compounds are stable up to 231-332 degreesC in the solid state. English AMER CHEMICAL SOC COORDINATION POLYMERS CHEMISTRY COMPLEX Smart molecular helical springs as tunable receptors Article 10.1021/ja001618b 1 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, v.122, no.41, pp.9921 - 9925 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 122 41 9921 9925 scie scopus 000090107600007 2-s2.0-0034684260 Chemistry, Multidisciplinary Chemistry Article COORDINATION POLYMERS CHEMISTRY COMPLEX spring