Synthesis, crystal structure, antibacterial and skin wound healing-promoting effect of nonanuclear bisacylhydrazone Tb cluster.

A novel nonanuclear terbium(III) cluster (9-Tb) supported by salicylaldehyde-condensed phenazinylpyridine bisacylhydrazone was designed, synthesized and fully characterized. Cluster 9-Tb shows excellent structural stability in various solution media. Antibacterial assays demonstrate that 9-Tb exhibits prominent inhibition against Staphylococcus aureus. The antibacterial activity may be attributed to the unique nonanuclear metal skeleton and the metal-organic synergistic effect derived from coordination assembly. In a Staphylococcus aureus-infected full-thickness skin wound model in SD rats, topical administration of 9-Tb remarkably accelerates wound closure. Further histological analyses reveal that 9-Tb facilitates collagen deposition, alleviates excessive inflammatory infiltration and promotes angiogenesis, thereby creating a favorable microenvironment for skin regeneration. In vivo biosafety assessment confirms no obvious organ damage or inflammatory lesions in major tissues of rats. Collectively, the nonanuclear terbium cluster 9-Tb integrates potent anti-Staphylococcus aureus activity, remarkable wound-healing efficacy and excellent biocompatibility, representing a promising candidate for antimicrobial and skin wound repair applications.