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The molecular titanium-oxo cluster [TiO(OPr)(OC Bu)] (1) can be photoactivated by UV light, resulting in a deeply coloured mixed valent (photoreduced) Ti (iii/iv) cluster, alongside alcohol and ketone (photooxidised) organic products. Mechanistic studies indicate that a two-electron (not free-radical) mechanism occurs in this process, which utilises the cluster structure to facilitate multielectron reactions. The photoreduced products [TiO(OPr)(OC Bu)(sol)], sol = PrOH (2) or pyridine (3), can be isolated in good yield and are structurally characterized, each with two, uniquely arranged, antiferromagnetically coupled d-electrons. 2 and 3 undergo onward oxidation under air, with 3 cleanly transforming into peroxide complex, [TiO(OPr)(OC Bu)(py)(O)] (5). 5 reacts with isopropanol to regenerate the initial cluster (1) completing a closed cycle, and suggesting opportunities for the deployment of these easily made and tuneable clusters for sustainable photocatalytic processes using air and light. The redox reactivity described here is only possible in a cluster with multiple Ti sites, which can perform multi-electron processes and can adjust its shape to accommodate changes in electron density.
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http://dx.doi.org/10.1039/d2sc05671b | DOI Listing |
Small
September 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Lanthanide-titanium-oxo clusters (LTOCs) exhibit promising luminescence potential owing to their unique core structures. In this study, the impact of ligand-to-metal charge transfer (LMCT, M = Ti) is systematically elucidated on the luminescence of LTOCs through crystal structure analysis, theoretical calculations, and photophysical measurements. The results reveal that the existence of the LMCT state disrupts the normal energy transfer process, thereby causing the failure of photo-excitation in LTOCs.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2025
Key Lab for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China.
While atomically monodisperse nanostructured materials with controllable heterometal dopants are highly desirable to unravel the structure-catalysis relationships, their controlled synthesis and atomic-level structural determination remain significant challenges. Here, we report on nanosized titanium-oxo clusters featuring two heterometallic sites, TiMOSal(HSal)(OCH)(CHOH) (denoted as TiM; M = MnCu, CaCu, Cu, Mn, Ca; Sal and HSal represent salicylate and 2-hydroxybenzoate, respectively), which were used for catalyzing and photocatalyzing the CO/epoxide cycloaddition to synthesize cyclic carbonates. Notably, the valence state of Cu is modulated by Mn in the TiMnCu cluster as Cu exists in the δ+ valence (1 < δ < 2), whereas in TiCu and TiCaCu, Cu is + 2 valence.
View Article and Find Full Text PDFChem Sci
April 2025
College of Chemistry and Chemical Engineering, Central South University Changsha 410083 Hunan P. R. China
Precise control over the distribution of active metal sites on catalyst surfaces is essential for maximizing catalytic efficiency. Addressing the limitations of traditional cluster catalysts with core-embedded catalytic sites, this work presents a strategy to position catalytic sites on the surfaces of oxide clusters. We utilize a calixarene-stabilized titanium-oxo cluster (TiL) as a scaffold to anchor Ag , forming the unique nanocluster TiAg with six surface-exposed Ag sites.
View Article and Find Full Text PDFChem Commun (Camb)
October 2024
College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
This review explores calixarenes, a prominent family of third-generation supramolecules celebrated for their distinct hollow, cavity-shaped structures. These macrocycles are intricately assembled by linking multiple phenolic units orthogonally through methylene (-CH-), sulfur (-S-), or sulfonyl (-SO-) bridges. This structural framework plays a pivotal role in the intricate assembly of nanoclusters, significantly advancing the field of cluster chemistry.
View Article and Find Full Text PDFJ Am Chem Soc
July 2024
Laboratory of Advanced Materials, Department of Chemistry, State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China.
Construction of mesoporous frameworks by noncovalent bonding still remains a great challenge. Here, we report a micelle-directed nanocluster modular self-assembly approach to synthesize a novel type of two-dimensional (2-D) hydrogen-bonded mesoporous frameworks (HMFs) for the first time based on nanoscale cluster units (1.0-3.
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