Copper(II) six-membered rings: a molecular mechanics and cluster analysis

Abstract

An agglomerative, hierarchical single-link clustering method was used to separate the different conformations of all the saturated six-membered copper(II) rings found in the Cambridge Structure Database. Three percent of all rings were found to be in the sofa and twist-boat conformations, one percent were boats and the rest chairs. There was no correlation between the coordination geometry of the copper(II) ion and the conformation of the six-membered ring. Changing the ligating atoms from nitrogen to sulfur had no effect on the conformational distribution of the six-membered rings. Molecular mechanics calculations were used to establish the reasons why high energy non-chair conformations wre adopted in certain cases.