Copper Clusters Containing Hydrides in Trigonal Pyramidal Geometry.

Structurally precise copper hydrides [CuH{SP(OPr)}(C≡CR)], R = Ph (), CHF (), and CHOMe (), were first synthesized from the polyhydrido copper cluster [CuH{SP(OPr)}] with nine equivalents of terminal alkynes. Later, their isolated yields were significantly improved by direct synthesis from [Cu(CHCN)](PF), [NH][SP(OPr)], NaBH, and alkynes along with NEt in THF. , , and were fully characterized by single-crystal X-ray diffraction, ESI-MS, and multinuclear NMR spectroscopy. All three clustershave 11 copper atoms, adopting 3,3,4,4,4-pentacapped trigonal prismatic geometry, with two hydrides inside the Cu cage, the position of which was ascertained by a single-crystal neutron diffraction structure of cluster co-crystallized with a [Cu(H){SP(OPr)}] () cluster. Six dithiophosphate and three alkynyl ligands stabilize the CuH core in which the two hydrides adopt a trigonal pyramidal coordination mode. This coordination mode is so far unprecedented for hydride. The H NMR resonance frequency of the two hydrides appears at 4.8 ppm, a value further confirmed by H NMR spectroscopy for their deuteride derivatives [Cu(D){SP(OPr)}(C≡CR)]. A DFT investigation allows understanding the bonding within this new type of copper(I) hydrides.