Bandgap Engineering of Titanium–Oxo Clusters: Labile Surface Sites Used for Ligand Substitution and Metal Incorporation

Abstract

Through the labile coordination sites of a robust phosphonate‐stabilized titanium–oxo cluster, 14 O‐donor ligands have been successfully introduced without changing the cluster core. The increasing electron‐withdrawing effect of the organic species allows the gradual reduction of the bandgaps of the {Ti6} complexes. Transition‐metal ions are then incorporated by the use of bifunctional O/N‐donor ligands, organizing these {Ti6} clusters into polymeric structures. The coordination environments of the applied metal ions show significant influence on their visible‐light adsorption. Both the above structural functionalizations also tune the photocatalytic H2 production activities of these clusters. This work provides a systematic bandgap engineering study of titanium–oxo clusters, which is important not only for their future photocatalytic applications, also for the better understanding of the structure–property relationships.

Oxo-Titanium(IV) Complex/Polymer Composites—Synthesis, Spectroscopic Characterization and Antimicrobial Activity Test

“…The analysis of these data confirms that the type of carboxylate ligand, which stabilizes the {Ti a O b } skeleton, is the main factor allowed to effectively control the HOMO-LUMO energy gap of multinuclear oxo-complexes. This effect was highlighted during earlier studies of Ti(IV)-oxo clusters of similar core structures and significant different carboxylate ligands [ 13 , 14 , 21 , 22 , 41 , 42 ]. The influence of the {Ti a O b } cluster core size on the HOMO-LUMO energy gap ( E g ) is definitely more negligible, e.g., the results of Cui et al’s investigations revealed that, for the {Ti 4 O}, {Ti 11 O 9 }, and {Ti 14 O 12 } clusters stabilized by O i Pr and 4-chlorosilicylate ligands, the E g values were 3.0, 2.8, and 2.9 eV, i.e., they differed from each other by 0.1 and 0.2 eV [ 42 ].…”

“…Studies of UV-Vis-DRS spectra revealed that the absorption maximum of the ( 1 )–( 4 ) compounds is shifted towards the visible range, i.e., 360–405 nm, with a sharp absorption edge between 480–520 nm ( Figure 3 ). The results of the previous investigations proved that the {Ti a O b } cores were absorbed in the UV range, which is due to the O2 p -Ti3 d charge transfer transition [ 41 ]. The shifting of the absorption to the visible range, which was registered in the spectra of the ( 1 )–( 4 ) compounds, can be explained by the ligand-to-core charge transfer (LCCT) from the -O 2 CR’ (R’ = 4-PhNH 2 or 4-PhOH) ligands to the tri- or tetranuclear titanium-oxo cores.…”

The ratio law of the structure evolution and stability for TinOm (n = 3–18, m = 1–2n) clusters

“…[14] Liu et al investigated bandgap engineering on titanium oxide clusters by substituting labile surface sites with ligand. [19] Based on their results, 14…”

“…[14] Liu et al investigated bandgap engineering on titanium oxide clusters by substituting labile surface sites with ligand. [19] Based on their results, 14 O-donor ligands have been successfully introduced without changing the cluster core.…”

An Organic–Inorganic Hybrid Material Based on Benzo[ghi]perylenetri-imide and Cyclic Titanium-Oxo Cluster for Efficient Perovskite and Organic Solar Cells

“…[22][23][24][25] To date, TOCs have been mainly applied in photocatalysis, host-guest ions selectivity, supporting single atom site/metallic nanomaterials, and porous materials. [26][27][28][29][30][31][32][33][34][35][36][37][38] Although organic chromophore appending TOCs have exhibited efficient electron communication and considerable photocurrent in model DSSCs, [39][40][41] there were few reports about the application in high performing photovoltaics. [42,43] One challenge is how to attach organic dyes onto TOCs, in which the trial-anderror one-pot approach is quite inefficient for bulky dye ligands protecting TOCs.…”