Two Pseudopolymorphic Star‐Shaped Tetranuclear Co3+ Compounds with Disulfide Anions Exhibiting Two Different Connection Modes and Promising Photocatalytic Properties. Issue 39 (13th August 2015)

• Record Type: Journal Article
• Authors: Pienack, Nicole; Lühmann, Henning; Djamil, John; Permien, Stefan; Näther, Christian; Haumann, Sebastian; Weihrich, Richard; Bensch, Wolfgang
• Is Part Of: Chemistry. Volume 21:Issue 39(2015)
• Page Start: 13637
• Page End: 13645
• Publication Date: 2015-08-13
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201501796
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The compound [Co<sub>4</sub>(C<sub>6</sub>H<sub>14</sub>N<sub>2</sub>)<sub>4</sub>(μ<sub>4</sub>‐S<sub>2</sub>)<sub>2</sub>(μ<sub>2</sub>‐S<sub>2</sub>)<sub>4</sub>] (<bold>I</bold>) and the pseudo‐polymorph [Co<sub>4</sub>(C<sub>6</sub>H<sub>14</sub>N<sub>2</sub>)<sub>4</sub>(μ<sub>4</sub>‐S<sub>2</sub>)<sub>2</sub>(μ<sub>2</sub>‐S<sub>2</sub>)<sub>4</sub>]<bold>⋅</bold>4 H<sub>2</sub>O (<bold>II</bold>) were obtained under solvothermal conditions (C<sub>6</sub>H<sub>14</sub>N<sub>2</sub>=<italic>trans</italic>‐1, 2‐diaminocyclohexane). The structures feature S<sub>2</sub><sup>2−</sup> ions exhibiting two different coordination modes. Terminal S<sub>2</sub><sup>2−</sup> entities join two Co<sup>3+</sup> centres in a μ<sub>2</sub> fashion, whereas the central S<sub>2</sub><sup>2−</sup> groups connect four Co<sup>3+</sup> cations in a μ<sub>4</sub>‐ coordination mode. Compound <bold>II</bold> can be transformed into compound <bold>I</bold> by heat and storage over P<sub>2</sub>O<sub>5</sub> and storing compound <bold>I</bold> in humid air yields in the formation of compound <bold>II</bold>. 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 μ<sub>4</sub>‐bridging S<sub>2</sub><sup>2−</sup> units and the short bonds for the S<sub>2</sub><sup>2−</sup> moieties in the μ<sub>2</sub>‐connecting mode. Photocatalytic hydrogen evolution experiments demonstrate the potential of compound <bold>II</bold> as catalyst.</p> </abstract>