Two Pseudopolymorphic Star‐Shaped Tetranuclear Co³⁺Compounds with Disulfide Anions Exhibiting Two Different Connection Modes and Promising Photocatalytic Properties

Abstract

The compound [Co4(C6H14N2)4(μ4-S2)2(μ2-S2)4] (I) and the pseudo-polymorph [Co4(C6H14N2)4(μ4-S2)2(μ2-S2)4]⋅4 H2O (II) were obtained under solvothermal conditions (C6H14N2=trans-1,2-diaminocyclohexane). The structures feature S2(2-) ions exhibiting two different coordination modes. Terminal S2(2-) entities join two Co(3+) centres in a μ2 fashion, whereas the central S2(2-) groups connect four Co(3+) cations in a μ4-coordination mode. Compound II can be transformed into compound I by heat and storage over P2O5 and storing compound I in humid air yields in the formation of compound II. The intermolecular interactions investigated through Hirshfeld surface analysis reveal that besides S⋅⋅⋅H bonding close contacts are associated with relatively weak H⋅⋅⋅H interactions. A detailed DFT analysis of the bonding situation explains the long S-S bonds in the μ4-bridging S2(2-) units and the short bonds for the S2(2-) moieties in the μ2-connecting mode. Photocatalytic hydrogen evolution experiments demonstrate the potential of compound II as catalyst.

Biomineralized Enzyme-Like Cobalt Sulfide Nanodots for Synergetic Phototherapy with Tumor Multimodal Imaging Navigation

“…Then, the mice were sacrificed at 2, 6, 24, and 72 h, organs (i.e., heart, liver, spleen, lung, kidney, blood, and tumor) were removed for Co quantitation by ICP-AES. As shown in Figure S2 of the SI, the Co 9 S 8 NDs mainly accumulated in the reticuloendothelial system (e.g., liver and spleen), similar to the in vivo biodistribution of other biomedical nanomaterials . Again, Co 9 S 8 NDs could be efficiently enriched in tumors after 2 h postinjection, even at 72 h postinjection, the accumulating amount was still 3.3% ID/g, probably owing to the enhanced permeation and retention effect. , The enhanced tumor accumulations were beneficial for highly sensitive and precise imaging, and also conducive for subsequent the photocatalytic synergetic therapy effect.…”

“…Cobalt chalcogenides nanomaterials have been emerged as photocatalysts for energy and environment applications. , Recently, some two-dimension cobalt chalcogenides nanomaterials (e.g., Co 9 Se 8 , Co x S) were fabricated for NIR light activatable PTT due to the broad optical absorption in the NIR window and high photothermal conversion efficiency. , Furthermore, cobalt-based nanomaterials also exhibited enzyme-like catalytic activity, so we deduce that the cobalt chalcogenide nanomaterials should also have enzymatic activity and have similar photocatalytic activity as that in the literature. , However, the reported biomedicine applications for cobalt chalcogenids nanomaterials suffered from rigorous synthetic conditions, abnormal morphology, or postsynthetic surface modification. In comparison with the two-dimension nanostructures, the ultrasmall nanoparticles are more applicable for systematic circulation of theranostic agents, which are regrettably not reported so far.…”