Cluster structures were generated via geometry optimization of reported crystal structures at the BP86+D3 /cc-pVDZ-pp level. Time-dependent density functional theory calculations were performed using the CAM-B3LYP+D3 /cc-pVDZ-pp functional to avoid well-known charge delocalization errors. Hirschfeld and Mulliken population analyses were performed using the MultiWFN package. All calculations were performed in the ORCA software package.