Structural Diversity in Molecular Nickel Phosphide Carbonyl Nanoclusters.

The reaction of [Ni(CO)] as a [NBu] salt in CHCl with 0.8 equiv of PCl afforded [NiP(CO)]. In contrast, the reactions of [Ni(CO)] as a [NEt] salt with 0.4-0.5 equiv of POCl afforded [NiP(CO)] ( = 0.84) or [NiP(CO)] by using CHCN and thf as a solvent, respectively. Moreover, by using 0.7-0.9 mol of POCl per mole of [NEt][Ni(CO)] both in CHCN and thf, [NiP(CO)] ( = 0.82) was obtained together with [NiP(CO)] as a side product. [NiP(CO)] ( = 0.82) and [NiP(CO)] were separated owing to their different solubility in organic solvents. All the new molecular nickel phosphide carbonyl nanoclusters were structurally characterized through single crystal X-ray diffraction (SC-XRD) as [NBu][NiP(CO)] (two different polymorphs, 2/ and 2/), [NEt][NiP(CO)]·CHCOCH·solv ( = 0.82), [NEt][NiP(CO)]·2thf, [NEt][NiP(CO)]·2CHCOCH( = 0.84) and [NEt][NiP(CO)]·CH·solv. The metal cores' sizes of these clusters range from 0.59 to 1.10 nm, and their overall dimensions including the CO ligands are 1.16-1.63 nm. In this respect, they are comparable to ultrasmall metal nanoparticles, molecular nanoclusters, or atomically precise metal nanoparticles. The environment of the P atoms within these molecular Ni-P-CO nanoclusters displays a rich diversity, that is, NiP pentagonal pyramid, NiP monocapped trigonal prism, NiP bicapped trigonal prism, NiP monocapped square antiprism, NiP sphenocorona, NiP bicapped square antiprism, and NiP icosahedron.