Three-Dimensional Superlattices Based on Unusual Chalcogenide Supertetrahedral In-Sn-S Nanoclusters

Atomically precise metal chalcogenide supertetrahedral clusters: frameworks to molecules, and structure to function

Metal chalcogenide supertetrahedral clusters (MCSCs) are of significance for developing crystalline porous framework materials and atomically precise cluster chemistry. Early research interest focused on the synthetic and structural chemistry of MCSC-based porous semiconductor materials with different cluster sizes/compositions and their applications in adsorption-based separation and optoelectronics. More recently, focus has shifted to the cluster chemistry of MCSCs to establish atomically precise structure-composition-property relationships, which are critical for regulating the properties and expanding the applications of MCSCs. Importantly, MCSCs are similar to II-VI or I-III-VI semiconductor nanocrystals (also called quantum dots, QDs) but avoid their inherent size polydispersity and structural ambiguity. Thus, discrete MCSCs, especially those that are solution-processable, could provide models for understanding various issues that cannot be easily clarified using QDs. This review covers three decades of efforts on MCSCs, including advancements in MCSC-based open frameworks (reticular chemistry), the precise structure-property relationships of MCSCs (cluster chemistry), and the functionalization and applications of MCSC-based microcrystals. An outlook on remaining problems to be solved and future trends is also presented.

Stable 3D neutral gallium thioantimonate frameworks decorated with transition metal complexes for a tunable photocatalytic hydrogen evolution

Incorporating transition metal (TM) complexes into cluster-based chalcogenide frameworks is an effective synthetic strategy to induce structural diversity and control the optoelectronic properties, which may further improve their photocatalytic performance. However, limited studies have been conducted on frameworks constructed by TM complexes covalently bonded with supertetrahedral Tn clusters, let alone on their properties, especially photocatalytic H₂ activity. Herein, three new isostructural three-dimensional (3D) neutral inorganic-organic open frameworks of gallium thioantimonate comprised of thiogallate-based supertetrahedral T3 clusters that are covalently bonded with TM complexes ([TM(TEPA)]²⁺, TM = Mn/Ni/Fe, TEPA = tetraethylenepentamine) at the edges and are linked by single Sb³⁺ ions at the corner, namely, NCF-3-Mn/Ni/Fe have been solvothermally synthesized and structurally characterized, and display good thermal and chemical stability. Benefiting from an adjustable TM centre, the title compounds possess tunable photocatalytic H₂ evolution activity, among which NCF-3-Mn exhibits the highest photocatalytic activity probably due to its favourable band structure and enhanced carrier separation efficiency.

Discrete Supertetrahedral T5 Selenide Clusters and Their Se/S Solid Solutions: Ionic-Liquid-Assisted Precursor Route Syntheses and Photocatalytic Properties

Although supertetrahedral Tn sulfide clusters (n=2-6) have been extensively explored, the synthesis of Tn selenide clusters with n>4 has not been achieved thus far. Reported here are ionic-liquid (IL)-assisted precursor route syntheses, characterizations, and the photocatalytic properties of six new M-In-Q (M=Cu or Cd; Q=Se or Se/S) chalcogenide compounds, namely [Bmmim]₁₂ Cu₅ In₃₀ Q₅₂ Cl₃ (Im) (Q=Se (T5-1), Se_48.5 S_3.5 (T5-2); Bmmim=1-butyl-2,3-dimethylimidazolium, Im=imidazole), [Bmmim]₁₁ Cd₆ In₂₈ Q₅₂ Cl₃ (MIm) (Q=Se (T5-3), Se_28.5 S_23.5 (T5-4), Se₁₆ S₃₆ (T5-5); MIm=1-methylimidazole), and [Bmmim]₉ Cd₆ In₂₈ Se₈ S₄₄ Cl(MIm)₃ (T5-6). The cluster compounds T5-1 and T5-3 represent the largest molecular supertetrahedral Tn selenide clusters to date. Under visible-light illumination, the Cu-In-Q compounds showed photocatalytic activity towards the decomposition of crystal violet, whereas the Cd-In-Q compounds exhibited good photocatalytic H₂ evolution activity. Interestingly, the experimental results show that the photocatalytic performances of the selenide/sulfide solid solutions were significantly better than those of their selenide analogues, for example, the degradation time of the organic dye with T5-2 was much shorter than that with T5-1, whereas the photocatalytic H₂ evolution efficiencies with T5-3-T5-6 improved significantly with increasing sulfur content. This work highlights the significance of IL-assisted precursor route synthesis and the tuning of photocatalytic properties through the formation of solid solutions.

A wide pH-range stable crystalline framework based on the largest tin-oxysulfide cluster [Sn20O10S34]

We report, herein, a diamond-like oxysulfide framework, 3D-T4-SnOS, based on the largest supertetrahedral cluster of Sn⁴⁺ ions, i.e. [Sn₂₀O₁₀S₃₄]. The framework remains intact in aqueous solution over a pH range between 1 and 14, and has a narrower optical bandgap, red-shifted fluorescence emission, and an enhanced photoelectric response compared to that of the smaller version, 2D-T3-SnOS, which has a building unit of supertetrahedral [Sn₁₀O₄S₂₀].

A new cluster-based chalcogenide zeolite analogue with a large inter-cluster bridging angle

A new cluster-based chalcogenide zeolite analogue with a large inter-cluster bridging angle.

Highly open chalcogenide frameworks built from unusual defective supertetrahedral clusters

Two highly open chalcogenide frameworks built from unusual supertetrahedral SBUs.