Reactivity of a Sterical Flexible Pentabenzylcyclopentadienyl Samarocene

Reactivity studies of the classical divalent lanthanide compound [Cp$^{Bz5}$$_{2}$Sm] (Cp$^{Bz5}$ = pentabenzylcyclopentadienyl-anion) towards diphenyl dichalcogenides and d-element carbonyl complexes led to remarkable results. In the compounds obtained, a different number of Sm-C(phenyl) interactions and differently oriented benzyl groups were observed, suggesting—despite the preference of these interactions in [Cp$^{Bz5}$$_{2}$Sm] described in previous studies—a flexible orientation of the benzyl groups and thus a variable steric shielding of the metal center by the ligand. The obtained compounds are either present as monometallic complexes (reduction of the dichalcogenides) or tetrametallic bridged compounds in the case of the d/f-element carbonyl complexes

Open questions on bonding involving lanthanide atoms

In-depth understanding of the bonding characteristics of the lanthanide ions in contemporary lanthanide-based materials is mandatory for tailoring their properties for novel applications. Here, the authors elaborate on open questions regarding the bonding situation in mainly molecular lanthanide (4f) compounds, where, as compared to their actinide (5f) analogs in which covalency of the bonds is a common feature, this is still under discussion for the 4f compounds

A dimolybdenum paddlewheel as a building block for heteromultimetallic structures

Diphenylphosphine functionalized propionic acid was applied for the synthesis of heteromultimetallic dimolybdenum(II) complexes. The ligand features both carboxylic acid and phosphine functionalities, allowing the selective synthesis of a tetracarboxylate bridged Mo2(II)-paddlewheel structure in a first step. Due to the symmetrically arranged phosphine functionalities, the dimolybdenum(II) complex was utilized as a metalloligand. Subsequent coordination of late transition metal ions, such as gold(I), rhodium(I), iridium(I) or ruthenium(II) to the phosphine moieties allowed the formation of heteromultimetallic structures. The flexibility of the diphenylphosphino propionate ligand system enabled intermolecular aurophilic interactions in the Au(I) functionalized dimolybdenum(II) complexes. Depending on the Au(I) species applied, either a dimeric structure or a 1D coordination polymer was formed in the solid state. These structures represent the first examples of heterometallic dimolybdenum(II) complexes, forming supramolecular structures via aurophilic interactions

Inverse vulcanization of trimethoxyvinylsilane particles

Elemental sulfur, a highly abundant waste product from natural gas and oil refining, can be used to create polymeric materials when reacted with unsaturated organic comonomers at elevated temperatures. Herein, we report on the inverse vulcanization of trimethoxyvinylsilane (TMVS) particles to obtain sulfur coated TMVS-sulfur (TMVS-S) particles with a sulfur content of 18.85 wt%. TMVS-S particles exhibit a high surface-to-volume ratio, insolubility, and can further be functionalized with N-vinylimidazole (NVIA) to incorporate N-donor ligands, known for copper(II) complexation. Adsorption experiments with aqueous solutions of mercury(II) and copper(II) ions revealed very good distribution coefficients of TMVS-S-NVIA particles for mercury and copper remediation, showcasing possibilities arising from combining inorganic siloxane and sulfur polymers towards novel adsorbent materials derived from abundant and commercially available compounds

A cyclopentadienyl functionalized silylene-a flexible ligand for Si- And C-coordination

The synthesis of a 1,2,3,4-tetramethylcyclopentadienyl (Cp$^{4}$) substituted four-membered N-heterocyclic silylene [{PhC(NtBu) $_{2}$}Si(C$_{5}$Me$_{4}$H)] is reported first. Then, selected reactions with transition metal and a calcium precursor are shown. The proton of the Cp$_{4}$-unit is labile. This results in two different reaction pathways: (1) deprotonation and (2) rearrangement reactions. Deprotonation was achieved by the reaction of [{PhC(NtBu) $_{2}$}Si(C$_{5}$Me$_{4}$H)] with suitable zinc precursors. Rearrangement to [{PhC(NtBu) $_{2}$}(C$_{5}$Me$_{4}$)SiH], featuring a formally tetravalent silicon R$_{2}$CSi(R′)-H unit, was observed when the proton of the Cp$^{4}$ ring was shifted from the Cp$^{4}$-ring to the silylene in the presence of a Lewis acid. This allows for the coordination of the Cp$^{4}$-ring to a calcium compound. Furthermore, upon reaction with transition metal dimers [MCl(cod)] $_{2}$ (M = Rh, Ir; cod = 1,5-cyclooctadiene) the proton stays at the Cp$^{4}$-ring and the silylene reacts as a sigma donor, which breaks the dimeric structure of the precursors

Activation of SO₂ by [Zn(Cp∗)₂] and [(Cp∗)ZnI-ZnI(Cp∗)]

Interesting reactivity was observed in reactions of SO2 with [Zn(Cp*)2] and [(Cp*)ZnI–ZnI(Cp*)]. These reactions proceeded with insertion of SO2 into the Zn–C bonds. Spectacularly, the lability of the C–S bond in the O2SCp* ligands led to the thermal decomposition of [Zn(O2SCp*)2(tmeda)] to afford [Zn2(μ-SO3)(μ-S2O4)(tmeda)2]

A Phosphine‐ß‐diketiminate Nickel(I)‐Complex for Small Molecule Activation

A bis(diphenyl)-phosphine functionalized ß-diketimine ligand (PNac-H) was applied for the synthesis of a subvalent Ni(I) complex [PNac-Ni]. Here, the Ni(I) center is stabilized by a tetradentate PNNP-type pocket, forming a square planar coordination sphere. Subsequently, the Ni(I) complex was investigated with regard to its reactivity and the activation of small molecules. The reductive potential of Ni(I) enabled an activation of different substrate classes, such as CH$_2$X$_2$ (X=Br, I), I$_2$ or Ph$_2$E$_2$ (E=S, Se). The ligand\u27s design allows a stabilization of the reactive Ni(I) species while at the same time enabling activation processes due to a hemilabile coordination behavior and accessible axial coordination sites. The activation products have been characterized by single crystal X-ray diffraction, NMR and IR spectroscopy as well as elemental analysis