Molekulare Lanthanoid‐Übergangsmetall‐Cluster mittels C‐H‐Bindungsaktivierung an polaren Metall‐Metall‐Bindungen

Self Cite

A comparative chemical bonding analysis for the germanides La2MGe6 (M=Li, Mg, Al, Zn, Cu, Ag, Pd) and Y2PdGe6 is presented, together with the crystal structure determination for M=Li, Mg, Cu, Ag. The studied compounds adopt the two closely related structure types oS72‐Ce2(Ga0.1Ge0.9)7 and mS36‐La2AlGe6, containing zigzag chains and corrugated layers of Ge atoms bridged by M species, with La/Y atoms located in the biggest cavities. Chemical bonding was studied by means of the quantum chemical position‐space techniques QTAIM (quantum theory of atoms in molecules), ELI‐D (electron localizability indicator), and their basin intersections. The new penultimate shell correction (PSC0) method was introduced to adapt the ELI‐D valence electron count to that expected from the periodic table of the elements. It plays a decisive role to balance the Ge−La polar‐covalent interactions against the Ge−M ones. In spite of covalently bonded Ge partial structures formally obeying the Zintl electron count for M=Mg2+, Zn2+, all the compounds reveal noticeable deviations from the conceptual 8−N picture due to significant polar‐covalent interactions of Ge with La and M ≠ Li, Mg atoms. For M=Li, Mg a formulation as a germanolanthanate M[La2Ge6] is appropriate. Moreover, the relative Laplacian of ELI‐D was discovered to reveal a chemically useful fine structure of the ELI‐D distribution being related to polyatomic bonding features. With the aid of this new tool, a consistent picture of La/Y−M interactions for the title compounds was extracted.

Section: Resultsmentioning

confidence: 99%

Polar‐Covalent Bonding Beyond the Zintl Picture in Intermetallic Rare‐Earth Germanides

Freccero

Solokha

Negri

et al. 2019

Self Cite

“…[12] Another example of the metalation of Cp ligands in systems with unsupported LuÀ Re bonds is the thermal decomposition of [Lu{(tBu) 2 C 6 H 3 O}-(CH 2 SiMe 3 )(Cp 2 Re)(thf)] to give a cluster compound in which LuÀRe bonds are supported by h 5 -m 4 -Cp ligands. [21] The observation of a low reaction rate together with the formation of side products that precluded the isolation of pure samples of 3 c made us think of alternative synthetic procedures. Similar to the preparation of 1, but avoiding the clearly unsuitable solvent THF, we performed a salt elimination reaction of [{Cp 2 LuCl} 2 ] with Li[Cp 2 Re] in toluene (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

Lanthanoid–Transition‐Metal Bonding in Bismetallocenes

Butovskii

Oelkers

Bauer

et al. 2014

Self Cite

Bismetallocenes [Cp2 LuReCp2 ] and [Cp*2 LaReCp2 ] (Cp=cyclopentadienyl; Cp*=pentamethylcyclopentadienyl) were prepared using different synthetic strategies. Salt metathesis-performed in aromatic hydrocarbons to avoid degradation pathways caused by THF-were identified as an attractive alternative to alkane elimination. Although alkane elimination is more attractive in the sense of its less elaborate workup, the rate of the reaction shows a strong dependence on the ionic radius of Ln(3+) (Ln=lanthanide) within a given ligand set. Steric hindrance can cause a dramatic decrease in the reaction rate of alkane elimination. In this case, salt metathesis should be considered the better alternative. Covalent bonding interactions between the Ln and transition-metal (TM) cations has been quantified on the basis of the delocalization index. Its magnitude lies within the range characteristic for bonds between transition metals. Secondary interactions were identified between carbon atoms of the Cp ligand of the transition metal and the Ln cation. Model calculations clearly indicated that the size of these interactions depends on the capability of the TM atom to act as an electron donor (i.e., a Lewis base). The consequences can even be derived from structural details. The observed clear dependency of the LuRu and interfragment LuC bonding on the THF coordination of the Lu atom points to a tunable Lewis acidity at the Ln site, which provides a method of significantly influencing the structure and the interfragment bonding.

“…To get insight into the reactivity of lanthanoid-transitionmetal bonds, [(2,6-tBu 2 C 6 H 3 O)LuA C H T U N G T R E N N U N G (CH 2 SiMe 3 )ReCp 2 ] (D7, Figure 5) was prepared by alkane elimination from [Cp 2 ReH] and the corresponding dialkyl lutetium phenolate. [79] As this complex contains both Lu-Re and Lu-C bonds, possible pathways of decomposition in systems with more than one metal-metal bond could be purposely investigated (see below). The lutetium coordination sphere is best described as tetrahedral with a metal-metal bond length of 284.98(6) pm.…”

Section: Rare-earth-transition Metal Bonds (Re-tm)mentioning

confidence: 99%

“…Among the many monoanionic ligands that are able to stabilize bisA C H T U N G T R E N N U N G (alkyl)-Ln complexes, deprotonated 2,6-di-tert-butylphenol proved to be a good choice. [79] The complex D7 (see below) having a reactive Ln alkyl and a reactive Ln-TM bond in close proximity could be obtained in good yield. This compound is unstable and decomposes to E1 (Scheme 1, Figure 6).…”

Section: Molecular Ln-tm Intermetalloidsmentioning

confidence: 99%

f‐Element–Metal Bonding and the Use of the Bond Polarity To Build Molecular Intermetalloids

Oelkers

Butovskii

Kempe

2012

Self Cite

Metal-metal bonding in heterobimetallic complexes is of fundamental interest due to its implications to both bonding theory and new reactivities. In this Concept, structurally authenticated molecular compounds with direct bonds between rare-earth metals or actinoids and transition or main group metals are summarized. Special attention is given to the use of bond polarity as a tool for designing molecular intermetalloids incorporating rare-earth atoms and transition metals.