Reactivity of mono- And divalent aluminium compounds towards group 15 nanoparticles

Herein, we present a novel approach towards organometallic group 13/15-compounds, i.e. the reaction of nanoparticular arsenic and antimony with low-valent aluminium species. The reaction of the two-electron reducing agent [AlCp*]$_{4}$ (Cp* = C$_{5}$Me$_{5}$) with arsenic nanoparticles gave rise to a mixture of two unprecedented deca- and dodecanuclear Al–As clusters. In contrast, the analogous transformation with nanoparticular antimony yielded the already known Al–Sb compound [(AlCp*)$_{3}$Sb$_{2}$]. Additionally, two different dialanes [AlCp*X]$_{2}$ (X = Br, I) were employed as one-electron reducing agents, forming calix like coordination compounds upon reaction with nano arsenic. The isolated species significantly enlarge the accessible structural variety of molecular group 13/15 compounds, highlighting the exceptional utility and reactivity of nanoscale group 15 precursors

From a nanoparticular solid-state material to molecular organo-f-element-polyarsenides

A convenient pathway to new molecular organo-lanthanide-polyarsenides in general and to a f-element complex with the largest polyarsenide ligand in detail is reported. For this purpose, the activation of the solid state material As$^{0}$$_{nano}$ (nanoscale gray arsenic) by the multi electron reducing agents [K(18-crown-6)][(Image Cp\u27\u27$_{2}$ Ln$^{+II}$)$_{2}$(μ-η$^{6}$:η$^{6}$-C$_{6}$H$_{6}$)] (Ln = La, Ce, Cp′′ = 1,3-bis(trimethylsilyl)cyclopentadienyl anion) and [K(18-crown-6)]$_{2}$[(Cp\u27\u27$_{2}$Ln$^{+II}$)$_{2}$(μ-η$^{6}$:η$^{6}$-C$_{6}$H$_{6}$)] (Ln = Ce, Nd) is shown. These non-classical divalent lanthanide compounds were used as three and four electron reducing agents where the product formation can be directed by variation of the applied reactant. The obtained Zintl anions As$_{3}$$^{3-}$, As$_{7}$$^{3-}$, and As$_{14}$$^{4-}$ were previously not accessible in molecular 4f-element chemistry. Additionally, the corresponding compounds with As$_{14}$$^{4-}$-moieties represent the largest organo-lanthanide-polyarsenides known to date

The Archetypal Homoleptic Lanthanide Quadruple-Decker—Synthesis, Mechanistic Studies, and Quantum Chemical Investigations

The synthesis of the first well-defined neutral and homoleptic (same metal, same ligand) all-carbon-based quadruple-decker complexes [Sm$^{III/II/III}$$_{3}$(COT$^{1,4-SiiPr3}$)$_{4}$] (COT$^{1,4-SiiPr3}$=1,4-($^{i}$Pr$_{3}$Si)$_{3}$C$_{8}$H$_{6}$)) along with other unique sandwich complexes is shown. Reduction of [Sm$^{III}$(COT$^{1,4-SiiPr3}(BH$$_{4}$)(thf)] (COT$^{1,4-SiiPr3}$=1,4-($^{i}$Pr$_{3}$Si)$_{3}$C$_{8}$H$_{6}$) with KC$_{8}$ resulted in [Sm$^{III/II/III}$$_{3}$(COT$^{1,4-SiiPr3}$)$_{4}$] the first example of a homoleptic lanthanide quadruple-decker. As indicated by an analysis of the bond metrics in the solid-state, the inner Sm ion is present in the divalent oxidation state, while the outer ones are trivalent. This observation could be confirmed by quantum chemical calculations. Mechanistic studies revealed not only insight into possible formation pathways of [Sm$^{III/II/III}$$_{3}$(COT$^{1,4-SiiPr3}$)$_{4}$] but also resulted in the transformation to other mixed metal sandwich complexes with unique structural properties. These are the 1D-polymeric chain structured [KSm$^{III}$(COT$^{1,4-SiiPr3}$)$_{4}$]$_{n}$ and the hexametallic species [(tol)K(COT$^{1,4-SiiPr3}$)Sm$^{II}$COT$^{1,4-SiiPr3}$)K]$_{2}$ which were initially envisioned as possible building blocks as part of different retrosynthetically guided pathways that we developed

Silole and germole complexes of lanthanum and cerium

Using dianionic metallole ligands (silole or germole) and the cyclooctatetraendiide dianion, heteroleptic lanthanide multi-decker complexes have been prepared. Due to the heteroatom of the metallole ligands intermolecular bridging between the sandwich complexes takes place. Our work highlights that different combinations of the lanthanide and heterocycle lead to different intermolecular interactions including a dimeric La-silole sandwich complex, a La-germole ladder-type polymeric species and a Ce-germole coordination polymer

Investigation of the Coordination Chemistry of a Bisamidinate Ferrocene Ligand with Cu, Ag, and Au

The coordination chemistry of a ferrocene ligand with one bulky amidinate function attached to each ring toward two different coinage metal precursors was investigated. In dependence of the metal and the co-ligands, “ansa” type structures and non-bridged structures were obtained. Six different compounds are reported. In the “ansa” type structures, short Fe–M (M = Cu, Ag) distances were observed in the molecular structures in the solid state. However, theoretical calculations (DFT) did not reveal a stabilizing metal–metal interaction. Instead, dispersion interactions within the ligand and between the ligand and metal seem to represent the main stabilization forces

Introduction of plumbole to f-element chemistry

Herein, we present the synthesis and characterization of heteroleptic lanthanide complexes bearing a dianionic η5-plumbole ligand in their coordination sphere. The reaction proceeds via a salt elimination reaction between the dilithioplumbole ([Li(thf)]$_2$[1,4-bis-tert-butyl-dimethylsilyl-2,3-bis-phenyl-plumbolyl] = [Li$_2$(thf)$_2$(η$^5$-L$^Pb$)]) and specifically designed [Ln(η$^8$-COT$^TIPS$)BH$_4$] precursors (Ln = lanthanide, La, Ce, Sm, Er; COT$^TIPS$ = 1,4-bis-triisopropylsilyl-cyclooctatetraenyl), that are capable of stabilizing a planar plumbole moiety in the coordination sphere of different trivalent lanthanide ions. In-depth ab initio calculations show that the aromaticity of the dianionic plumbole is retained upon coordination. Electron delocalization occurs from the plumbole HOMO to an orbital of mainly d-character at the lanthanide ion. The magnetic properties of the erbium congener were investigated in detail, leading to the observation of magnetic hysteresis up to 5 K (200 Oe s$^−1$), an unequivocal proof for single molecule magnet behavior in this system. The magnetic behavior of the erbium species can be modulated by manipulating the position of the lithium cation in the complex, which directly influences the bonding metrics in the central [(η$^5$-L$^Pb$)Er(η$^8$-COT$^TIPS$)]− fragment. This allowed us to assess a fundamental magneto-structural correlation in an otherwise identical inner coordination sphere

Alkali Metal Complexes of a Bis(diphenylphosphino)methane Functionalized Amidinate Ligand: Synthesis and Luminescence

A novel bis(diphenylphosphino)methane (DPPM) functionalized amidine ligand (DPPM−C(N-Dipp)$_{2}$H) (Dipp=2,6-diisopropylphenyl) was synthesized. Subsequent deprotonation with suitable alkali metal bases resulted in the corresponding complexes [M{DPPM−C(N-Dipp)$_{2}$}(Ln)] (M=Li, Na, K, Rb, Cs; L=thf, Et$_{2}$O). The alkali metal complexes form monomeric species in the solid state, exhibiting intramolecular metal-π-interactions. In addition, a caesium derivative [Cs{PPh$_{2}$CH$_{2}$-C(N-Dipp)$_{2}$}]$_{6}$ was obtained by cleavage of a diphenylphosphino moiety, forming an unusual six-membered ring structure in the solid state. All complexes were fully characterized by single crystal X-ray diffraction, NMR spectroscopy, IR spectroscopy as well as elemental analysis. Furthermore, the photoluminescent properties of the complexes were thoroughly investigated, revealing differences in emission with regards to the respective alkali metal. Interestingly, the hexanuclear [Cs{PPh$_{2}$CH$_{2}$-C(N-Dipp)$_{2}$}]$_{6}$ metallocycle exhibits a blue emission in the solid state, which is significantly red-shifted at low temperatures. The bifunctional design of the ligand, featuring orthogonal donor atoms (N vs. P) and a high steric demand, is highly promising for the construction of advanced metal and main group complexes