Achieving Structural Evolution from Sn 7 to Sn 7 Mo 12 for Efficient Near‐Infrared Photothermal Conversion via a Redox Coordination Hierarchical Strategy

Comprehensive Summary Non‐alkyl tin‐oxo clusters (SnOCs) feature structural precision and designability, enabling their photophysical properties to be modulated through transition‐metal doping and thus holding great promise for solar‐driven photothermal conversion. However, such doped SnOCs still face a critical challenge of lacking controlled synthetic strategies. Herein, a redox‐coordination hierarchical strategy is developed for non‐alkyl SnOCs, exploiting the redox reaction between high‐valent molybdenum source (Na 2 Mo VI O 4 ) and low‐valent tin source (Sn II Cl 2 ) to achieve a structural transformation from hourglass‐shaped Sn 7 to pedestal‐hourglass‐shaped Sn 7 Mo 12 . The resulting structure gives rise to strong Mo–Mo interactions and ligand‐to‐metal charge transfer (LMCT) that together dramatically reduce the optical bandgap from 4.35 eV ( Sn 7 ) to 2.04 eV ( Sn 7 Mo 12 ). Consequently, Sn 7 Mo 12 exhibits an extended absorption spectrum into the near‐infrared region and achieves a high photothermal conversion efficiency of 85.61%. Moreover, the material demonstrates a solar‐driven water evaporation rate of 0.97 kg·m –2 ·h –1 and an evaporation efficiency of 55.65%. This work not only provides new insights into the rational design and controlled synthesis of broadband‐absorbing photothermal materials but also lays a crucial foundation for the functional development of heterometallic SnOCs.