Structural Diversity in Molecular Nickel Phosphide Carbonyl Nanoclusters

[Image: see text] The reaction of [Ni(6)(CO)(12)](2–) as a [NBu(4)](+) salt in CH(2)Cl(2) with 0.8 equiv of PCl(3) afforded [Ni(14)P(2)(CO)(22)](2–). In contrast, the reactions of [Ni(6)(CO)(12)](2–) as a [NEt(4)](+) salt with 0.4–0.5 equiv of POCl(3) afforded [Ni(22–x)P(2)(CO)(29–x)](4–) (x = 0.84) or [Ni(39)P(3)(CO)(44)](6–) by using CH(3)CN and thf as a solvent, respectively. Moreover, by using 0.7–0.9 mol of POCl(3) per mole of [NEt(4)](2)[Ni(6)(CO)(12)] both in CH(3)CN and thf, [Ni(23–x)P(2)(CO)(30–x)](4–) (x = 0.82) was obtained together with [Ni(22)P(6)(CO)(30)](2–) as a side product. [Ni(23–x)P(2)(CO)(30–x)](4–) (x = 0.82) and [Ni(22)P(6)(CO)(30)](2–) 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(4)](2)[Ni(14)P(2)(CO)(22)] (two different polymorphs, P2(1)/n and C2/c), [NEt(4)](4)[Ni(23–x)P(2)(CO)(30–x)]·CH(3)COCH(3)·solv (x = 0.82), [NEt(4)](2)[Ni(22)P(6)(CO)(30)]·2thf, [NEt(4)](4)[Ni(22–x)P(2)(CO)(29–x)]·2CH(3)COCH(3)( x = 0.84) and [NEt(4)](6)[Ni(39)P(3)(CO)(44)]·C(6)H(14)·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, Ni(5)P pentagonal pyramid, Ni(7)P monocapped trigonal prism, Ni(8)P bicapped trigonal prism, Ni(9)P monocapped square antiprism, Ni(10)P sphenocorona, Ni(10)P bicapped square antiprism, and Ni(12)P icosahedron.