Cu28H20: a peculiar chiral nanocluster with an exposed Cu atom and 13 surface hydrides.

ABSTRACT

Reported herein is a racemate of a chiral nanocluster [Cu28H20(S2P(OiPr)2)9]-, which has a tetrahedral Cu4 core embedded in a peculiar Cu24 shell. The Cu28H20 framework conforms to idealized C3 symmetry. The positions of the hydrides were determined by a combinatorial use of 2H NMR and SC-XRD, revealing four different coordination modes face-capping µ3-H, butterfly µ4'-H, tetrahedral µ4-H, and square-pyramidal µ5-H. These coordination modes were authenticated by DFT calculations. Simple empirical rules were developed for assigning the H NMR spectra. One exposed Cu atom from the Cu4 core and 13 exposed surface hydrides are easily accessible and thus may have catalytic functions.