Diselenophosphate-Induced Conversion of an Achiral [Cu20H11{S2P(OiPr)2}9] into a Chiral [Cu20H11{Se2P(OiPr)2}9] Polyhydrido Nanocluster

A polyhydrido copper nanocluster, [Cu20H11{Se2P(OiPr)(2)}(9)] (2(H)), which exhibits an intrinsically chiral inorganic core of C-3 symmetry, was synthesized from achiral [Cu20H11{S2P(OiPr)(2)}(9)] (1(H)) of C-3h symmetry by a ligand-exchange method. The structure has a distorted cuboctahedral Cu-13 core, two triangular faces of which are capped along the C-3 axis, one by a Cu-6 cupola and the other by a single Cu atom. The Cu-20 framework is further stabilized by 9 diselenophosphate and 11 hydride ligands. The number of hydride, phosphorus, and selenium resonances and their splitting patterns in multinuclear NMR spectra of 2(H) indicate that the chiral Cu20H11 core retains its C-3 symmetry in solution. The 11 hydride ligands were located by neutron diffraction experiments and shown to be capping (3)-H and interstitial (5)-H ligands (in square-pyramidal and trigonal-bipyramidal cavities), as supported by DFT calculations on [Cu20H11(Se2PH2)(9)] (2(H)) as a simplified model.