[Co₂@Ge₁₆]⁴⁻: Localized versus Delocalized Bonding in Two Isomeric Intermetalloid Clusters

Abstract

We report the successful isolation and structural elucidation of two bimetallic doped [Co @Ge ] clusters (α and β form), which were synthesized through the reaction of [{(ArN) CtBu}Co(η -toluene)] (Ar=2,6-diisopropylphenyl) and K Ge in ethylenediamine (en) solution and co-crystallized together in [K(2,2,2-crypt)] [Co @Ge ]⋅en. The α-[Co @Ge ] isomer prefers a distinct D 3-connected architecture, whereas the deltahedral isomeric β-[Co @Ge ] isomer adopts a quasi-C geometry and can be seen as coupling of two distorted arachno-[Co@Ge ] units. Chemical bonding analyses indicate that the skeleton of the α isomer is mainly composed of localized bonds, whereas only multicenter bonding interactions govern the geometry of the β isomer, which was further found to exhibit a fluxional behavior. The coexistence of both isomers within one unit cell links the 3-connected clusters with their deltahedral congeners, thus highlighting the structural and electronic flexibility of such discreet cluster systems.

Structure and Bonding in [Sb@In8Sb12]3− and [Sb@In8Sb12]5−

“…The outer Sb 12 In 8 shell can be considered topologically related to the Sb 20 unit of [Sb@M 12 @Sb 20 ] q − , but the presence of a single Sb atom inside the cluster rather than an icosahedral Sb@M 12 unit pulls the eight In vertexes inwards, so that only they bond directly with the central Sb atom. The cubic coordination of Sb is also broadly consistent with the known structural chemistry of centered main‐group (semi‐)metal cages . The gas‐phase potential energy surface for the [Sb@In 8 Sb 12 ] 5− cluster is complex, featuring eight equivalent minima with a single displaced In + center, linked by low‐lying transition states where the additional electron pair is delocalized over two adjacent In centers (similar to the situation found in the trans ‐bent double bonds, R 2 E=ER 2 , of the heavier group‐IV elements).…”

Endohedral Plumbaspherenes of the Group 9 Metals: Synthesis, Structure and Properties of the [M@Pb12]3− (M=Co, Rh, Ir) Ions

“…Compound 1 gives rise to ab road 59 Co NMR resonance at À1989 ppm, with al ine width of 606 Hz (Figure 6a,r ight). The 59 Co NMR chemical shifts have been correlated with the formal oxidation states [34][35][36] and the À1989ppm value for 1 is consistent with aÀ1o xidation state. This finding is consistent with our oxidation state formalismsd escribed above.…”

Interplay Between Planar and Spherical Aromaticity: Shielding Cone Behavior in Dual Planar‐Planar, Planar‐Spherical and Spherical‐Spherical Aromatics

“…As an extension to this concept, spherical‐like structures also enable similar properties related historically to π‐planar species, among monolayers, expanded molecules, and other species, which can be explored in different metallic clusters …”