Proton Transfer in a New Chain-Like Cluster Compound H[Lu(H2O)6{Re4Te4(CN)12}]·6H2O

A novel solid acid hydrate H[Lu(H20)6{Re4Te4(CN) 12 }]·6H 2 O was synthesized. The compound was studied with single-crystal X-ray diffraction and wide-line 1 H NMR spectroscopy. The building blocks of the compound are formed by [Re 4 Te 4 (CN) 12 ] 4- cluster anions linked through {Lu(H 2 O) 6 } 3+ cationic complexes in infinite linear chains. The chains form a quasi 1-D structure with channels occupied with oxygen-protonated ensembles. A temperature variation triggers a two-stage evolution of intermolecular proton exchange corresponding to activation energies of 16 and 43 kJ/mol. The stages are interpreted as a step-by-step process of the solvate and coordinate water molecules becoming involved in the proton-transfer reactions. It was hypothesized that the mechanism of proton exchange includes the Grotthuss-type proton translocation in the protonated water fragments and the continual rearrangement of protonated and unprotonated fragments in the structure channels due to H 2 O molecular diffusion.