Synthesis and structural characterization of inverse-coordination clusters from a two-electron superatomic copper nanocluster.

ABSTRACT: We have synthesized and structurally characterized a series of centred cuboctahedral copper clusters, namely [Cu₁₃{S₂CNR₂}₆{C[triple bond, length as m-dash]CR'}₄](PF₆), 1a-d (where a: R = ⁿ Bu, R' = CO₂Me; b: R = ⁿ Bu, R' = CO₂Et; c: R = ⁱPr, R' = CO₂Et; d: R = ⁿ Pr, R' = 3,5-(CF₃)₂C₆H₃); [Cu₁₂(?₁₂-S){S₂CNR₂}₆{C[triple bond, length as m-dash]CR'}₄], 2a-c; [Cu₁₂(?₁₂-Cl){S₂CNR₂}₆{C[triple bond, length as m-dash]CR'}₄](PF₆), 3a-e (where e: R = ⁿ Bu, R' = Ph); [Cu₁₂(?₁₂-Br){S₂CN ⁿ Bu₂}₆{C[triple bond, length as m-dash]CPh}₄](PF₆), 4e; and [Cu₁₂(?₁₂-Cl)(?₃-Cl){S₂CN ⁿ Bu₂}₆{C[triple bond, length as m-dash]CCO₂Me}₃]⁺ 5a. Cluster 1a is the first structurally characterized copper cluster having a Cu₁₃ centered cuboctahedral arrangement, a miniature of the bulk copper fcc structure. Furthermore, the partial Cu(0) character in the 2-electron superatoms 1 was confirmed by XANES. Inverse coordination clusters 2-5 are the first examples of copper clusters containing main group elements (Cl, Br, S) with a hyper-coordination number, twelve. A combined theoretical and experimental study was performed, which shows that the central copper (formally Cu^1-) in nanoclusters 1 can be replaced by chalcogen/halogen atoms, resulting in the formation of clusters 2-5 which show enhanced luminescence properties and increase in the ionic component of the host-guest interaction as Br ? Cl > S > Cu, which is consistent with the Cu-X Wiberg indices. The new compounds have been characterized by ESI-MS, ¹H, ¹³C NMR, IR, UV-visible, emission spectroscopy, and the structures 2a-b, 3d-e, 4e and 5a were established by X-ray diffraction analysis.

SUBMITTER: Chakrahari KK 

PROVIDER: S-EPMC6115619 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature