Synthesis and structural-bonding analysis of the [Ni8(PCMe3∥2(PMe)2(CO)12]n series (n= 0,2–): polyhedral rearrangement of the electron-precise (µ5-Ni)2(µ4-P)2-tetracapped Ni6P2 cuneane framework in the neutral parent into an electron-delocalized noncentred Ni8P4 icosahedral cage in the dianion by a two-electron chemical reduction

Abstract

[Ni₈(PCMe₃)₂(PMe)₂(CO)₁₂], 1, which contains a Ni₆P₂cuneane framework (with a wedge-shaped P-P edge) capped on its two Ni₃P₂ pentagonal faces by nickel atoms and on its two Ni₄ rectangular faces by phosphorus atoms, undergoes a skeletal rearrangement upon a two-electron reduction with K/benzophenone to give the sought-after centrosymmetric [Ni₈(PCMe₃)₂[PMe)₂(CO)₁₂]^2–, 2, which contains a noncentred pseudo-D_2h 1,2,9,12-Ni₈P₄ icosahedral cage; this reduction-induced conversion illustrates the unprecedented geometrical transformation of a 12-vertex tetracapped cuneane polyhedron with 12 skeletal electron pairs into a noncentred 12-vertex icosahedral polyhedron with 13 skeletal electron pairs via a diamond–square–diamond (DSD) rearrangement.