Molecular mechanics and cluster analysis of nickel(II) six-membered rings

Abstract

An agglomerative, hierarchical, single-link cluster analysis was used to find all the conformational families available to nickel(II) six-membered rings. All saturated nickel(II) solid-state structures in the Cambridge Structure Database were clustered. The reasons why high-energy non-chair conformations are adopted were analysed by molecular mechanics. The high-energy structures of sixteen-membered tetraaza- and tetrathia-macrocycles can only be accounted for by assuming that they are artifacts of their metal incorporation mechanism. No correlation between the conformation and the spin state of the nickel(II) or the co-ordination geometry was found. The identity of the ligating atoms did not affect the co-ordination geometry or ring conformation.