In this work, two heterometallic clusters, namely Ti^IV₄Mo^V₄Mo^VI₂O₁₆(OCH₃)₁₆ (1) and Ti^IV₄Mo^V₄O₁₀(OC₂H₅)₁₄ (C₆H₅COO)₂ (2) are successfully constructed to improve the solar absorption and performance of titanium oxo clusters (TOCs). The 1 and 2 structures are determined well by single-crystal X-ray diffraction analysis and found to feature the common presence of Mo–Mo interactions. The solid-state UV–vis absorption studies indicate that these structures exhibit enhanced visible-light absorption and significantly reduced optical band gaps, which should be dominantly attributed to the introduction of electron-rich Mo–Mo pairs as heterometals. This work demonstrates an effective strategy of regulating the light absorption behaviors of TOCs by importing electron-rich heterometals.

In this study, the size of the titanium organic cage was controlled to achieve the restricted growth from a single Ag(I) atom (Ag@Ti₅) to rare all-carboxylate-protected superatomic Ag cluster (Ag₆@Ti₆). The classical octahedral Ag₆⁴⁺ cluster with two delocalized electrons (2e) has been encapsulated in a Ti₆ organic cage, which shows high stability in air and dimethyformamide (DMF). Furthermore, larger 2e nested double-tetrahedra Ag clusters (Ag₈⁶⁺ and Ag₉⁷⁺) protected using a tetrahedral hollow metalloligand framework (Ag₈@Ti₄ and Ag₉@Ti₄) were obtained. Electrospray ionization mass spectrometry (ESI-MS) and density functional theory (DFT) calculations confirmed that there are two delocalized electrons on these small Ag clusters. This study provides a new form of protection for superatomic Ag clusters and provides a feasible strategy for the development of stable Ag clusters.