research papers
A methodology for the conformational study of cyclic systems through the statistical analysis of torsion angles is presented. It relies on a combination of different methods based on a probabilistic model which takes into account the topological symmetry of the structures. This methodology is applied to copper complexes double-bridged by phosphate and related ligands. Structures from the Cambridge Structural Database (CSD) are analyzed and the chair, boat-chair and boat conformations are identified as the most frequent conformations. The output of the methodology also provides information about distortions from the ideal conformations, the most frequent being: chair ↔ twist-chair, chair ↔ twist-boat-chair and boat ↔ twist-boat. Molecular mechanics calculations identify these distortions as energetically accessible pathways.
Keywords: molecular mechanics; Cambridge Structural Database; conformation analysis; cyclic systems.
Supporting information
Portable Document Format (PDF) file https://doi.org/10.1107/S0108768107050859/bs5051sup1.pdf |