Predicting the coordination environment and magnetic properties of interlocked Co II complexes. To test our hypothesis that the coordination environment of rotaxane-based metal complexes can be predicted with reasonable precision, we compared our previously reported solid-state structure of [Co(1)](ClO4)2 (see Figure for ligand structures) derived from single crystal x-ray diffraction (SCXRD) analysis (Figure ) with modelled structures generated de novo (Gaussian '09, CAM-B3LYP/6-31G*/LAN2DZ [Co], see ESI for details). It is important to note that attempts to synthesize a non-interlocked equivalent to [Co(1)](ClO4)2 results in formation of a homoleptic, 6-coordinate complex incorporating two pyridine bis-triazole ligands, whereas the rotaxane framework enforces the formation of a pseudo-heteroleptic complex and prevents binding of additional ligands, to give a predictable, if relatively rare, 5 coordinate all-neutral N-donor distorted square-based pyramidal (sbpy) binding mode.