Figure Final cluster options and their simulated XPDF patterns, with key peak areas highlighted, and an in situ dataset of a linker-free reaction at 150°C for comparison. Cluster structure colour scheme: Hf, blue; O, red; H, white. Cluster structure models were obtained from crystal structure files and edited using the VESTA programme to give the Hf analogues and remove peripheral ligands. In order to obtain our cluster models, we removed peripheral ligands from the original structures.