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

Abstract

The icosahedral [M@Pb 12 ] 3À (M = Co(1), Rh(2), Ir(3)) cluster ions were prepared from K 4 Pb 9 and Co(dppe)Cl 2 (dppe = 1,2-bis(diphenylphosphino)ethane)/[Rh(PPh 3 ) 3 Cl]/[Ir-(cod)Cl] 2 (cod = 1,5-cyclooctadiene), respectively,i nt he presence of 18-crown-6/ 2,2,2-cryptand in ethylenediamine/toluene solvent mixtures. The [K(2,2,2-cryptand)] + salt of 1 and the [K(18-crown-6)] + salt of 3 were characterized via X-ray crystallography; the ions 1 and 3 are isostructural and isoelectronic to the [Rh@Pb 12 ] 3À (2)i on as well as to the group 10 clusters [M'@Pb 12 ] 2À (M' = Ni, Pd, Pt). The ions are all 26-electron clusters with nearp erfect icosahedral I h point symmetry.C lusters 1-3 show record downfield 207 Pb NMR chemicals hifts duet os-aromaticity of the cluster framework. Calculated and observed 207 Pb NMR chemical shifts and 207 Pb-x M J-couplings ( x M = 59 Co, 103 Rh, 193 Ir) are in excellent agreement and DFT analysis shows that the variations of 207 Pb NMR chemical shifts for the [M@Pb 12 ] 2, 3À ions (M = Co, Rh, Ir,N i, Pd, Pt) are mainly governed by the perpendicularly oriented s 11 component of the chemical shift anisotropy tensor. The laser desorption ionization time-of-flight (LDI-TOF) mass spectra contain the molecular ions as well as several new gas phase clusters derived from the parents. The DFT-minimized structures of these ions are described.[a] Dr.

A family of lead clusters with precious metal cores

“…2) are all~3.01 Å while the distances to Pb2-6 are somewhat longer at 3.09 Å. The Pb-Pb bond lengths vary between 3.15 and 3.30 Å, and are very similar to those reported for the closo clusters [M@Pb 10 ] 2− and [M@Pb 12 ] 2−/3− discussed in the introduction [16][17][18][19][20][21][22][23] . The characteristic valence electron count of 48 (4n + 4) for a nido 11-vertex polyhedron 28 demands a charge of 4-on the Pb 11 cluster, consistent with the presence of an Ag ion in the +1 oxidation state (i.e., d 10 ).…”

Symmetry collapse due to the presence of multiple local aromaticity in Ge244−

“…Such behavior may be useful to understand the role of Co(dppe)Cl 2 in the synthesis of Ge 24 4− cluster. Besides, several Co-centered cluster species have been also prepared by reactions with different Co complexes, such as [Co@Ge 10 ] 3− 19 , [Co 2 @Ge 16 ] 4− 20 , 21 , [Co@M 12 ] 3− (M = Ge/Pb) 22 , 23 , [Co@Sn 6 Sb 6 ] 3− and [Co 2 @Sn 5 Sb 7 ] 3− 24 . Interestingly, the [Co 2 @Ge 16 ] 4− anion contained two types of cluster units (α and β form) and could be obtained by using different Co reagents, Co(PPhEt 2 ) 2 (mes) 2 and [{(ArN) 2 C t Bu}Co(η 6 -toluene)].…”

Bridging Aromatic/Antiaromatic Units: Recent Advances in Aromaticity and Antiaromaticity in Main‐Group and Transition‐Metal Clusters from Bonding and Magnetic Analyses

“…In addition to the linear aggregation of different aromatic/antiaromatic motifs discussed above, the exploration of clusters consisting of a multilayered structure is also important, due to their potential in finding aromatic sub‐clusters embedded into larger cages. This pattern is usually found in structures with one or two layers, as recently discussed for [Ge 9 ] 4− , [M@Pb 12 ] 3− and [Pd 3 Sn 8 Bi 6 ] 4− Zintl clusters [56,91,158] . In 2011, Fässler and coworkers characterized an all‐metal [Sn@Cu 12 @Sn 20 ] 12− cluster, being a spectacular example of a structure accommodating three concentric structural layers [163] .…”

“…The recognition of cage‐like clusters displaying spherical aromaticity, reported by Hirsch and coworkers, [36,47] enables the extension of the aromaticity concept to 3D species. Great advances in the synthesis and characterization of Zintl‐ion derivatives [48–67] gave rise to a relevant increase in the number of challenging aromatic species with a wide range of molecular architectures and compositions. Early relevant contributions to the field have been provided by Cummins, Scheer, Robinson, Power, Schnoeckel, Fischer, Fässler, Aldridge and Mountford, among other research groups, increasing the number of examples exhibiting aromaticity in inorganic clusters [68–82] …”