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Two Pseudopolymorphic Star‐Shaped Tetranuclear Co 3+ Compounds with Disulfide Anions Exhibiting Two Different Connection Modes and Promising Photocatalytic Properties
Author(s) -
Pienack Nicole,
Lühmann Henning,
Djamil John,
Permien Stefan,
Näther Christian,
Haumann Sebastian,
Weihrich Richard,
Bensch Wolfgang
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501796
Subject(s) - photocatalysis , connection (principal bundle) , disulfide bond , star (game theory) , materials science , chemistry , crystallography , physics , catalysis , organic chemistry , mathematics , astrophysics , geometry , biochemistry
The compound [Co 4 (C 6 H 14 N 2 ) 4 (μ 4 ‐S 2 ) 2 (μ 2 ‐S 2 ) 4 ] ( I ) and the pseudo‐polymorph [Co 4 (C 6 H 14 N 2 ) 4 (μ 4 ‐S 2 ) 2 (μ 2 ‐S 2 ) 4 ] ⋅ 4 H 2 O ( II ) were obtained under solvothermal conditions (C 6 H 14 N 2 = trans ‐1,2‐diaminocyclohexane). The structures feature S 2 2− ions exhibiting two different coordination modes. Terminal S 2 2− entities join two Co 3+ centres in a μ 2 fashion, whereas the central S 2 2− groups connect four Co 3+ cations in a μ 4 ‐ coordination mode. Compound II can be transformed into compound I by heat and storage over P 2 O 5 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 SS bonds in the μ 4 ‐bridging S 2 2− units and the short bonds for the S 2 2− moieties in the μ 2 ‐connecting mode. Photocatalytic hydrogen evolution experiments demonstrate the potential of compound II as catalyst.