{Sn9[Si(SiMe3)3]3}− and {Sn8Si[Si(SiMe3)3]3}−: variations of the E9 cage of metalloid group 14 clusters

Sn368‒: A 2.7 nm Naked Aromatic Tin Rod

In this work, we synthesize naked tin cluster anion Sn368‒, representing the first example of pure Sn nanowire assembled through oxidative coupling reactions of a super atomic cluster Sn94-. Theoretical...

Endohedral group-14-element clusters TM@E9 (TM = Co, Ni, Cu; E = Ge, Sn, Pb) and their low-dimensional nanostructures: a first-principles study

Endohedral group14-based clusters with the encapsulation of a transition metal, which are termed [TM@E_m]^n- (TM = transition metal and E = group-14 elements), have lots of potential applications and have been used as interesting building blocks in materials science. Nevertheless, their electronic structures and stability mechanism remain unclear. In this paper, we systematically study the geometries, electronic structures, and bonding properties of [TM@E₉]^n- clusters which are the smallest endohedral group-14-based clusters synthesized so far, by using density functional theory (DFT) calculations. The calculation results reveal the important role of TMs in affecting the structures and bonding interactions in the [TM@E₉]^n- cluster. In the presence of a TM, the cluster geometry could change from a monocapped square antiprism (C_4v) for empty [E₉]^4- cages to a tricapped trigonal prismatic geometry (D_3h) for [TM@E₉]^n-. By using the energy decomposition analysis (EDA) method, the bonding properties between the endohedral TM and E₉ cluster have been thoroughly investigated. It was found that the origin of stability of these clusters is from the large electrostatic attraction with significantly reduced Pauli repulsion. In the case of orbital interactions, the π back-donations from d orbitals of the TM to the cluster make important contributions. More interestingly, the 1D-chain and 2D-sheet nanostructures based on the [Ni@E₉] cluster have been theoretically predicted. The band structure and density of states analysis revealed that all of these nanostructures are metallic and their excellent thermodynamic stability has been confirmed by using ab initio molecular dynamics (AIMD) simulations.

LiGe(SiMe₃)₃: A New Substituent for the Synthesis of Metalloid Tin Clusters from Metastable Sn(I) Halide Solutions

The most fruitful synthetic route to metalloid tin clusters applies the disproportionation reaction of metastable Sn(I) halide solutions, whereby Si(SiMe₃)₃ is mostly used as the stabilizing substituent. Here, we describe the synthesis and application of the slightly modified substituent Ge(SiMe₃)₃, which can be used for the synthesis of metalloid tin clusters to give the neutral cluster Sn10[Ge(SiMe₃)₃]₆ as well as the charged clusters {Sn10[Ge(SiMe₃)₃]₅}− and {Sn10[Ge(SiMe₃)₃]₄}2−. The obtained metalloid clusters are structurally similar to their Si(SiMe₃)₃ derivatives. However, differences with respect to the stability in solution are observed. Additionally, a different electronic situation for the tin atoms is realized as shown by 119mSn Mössbauer spectroscopy, giving further insight into the different kinds of tin atoms within the metalloid cluster {Sn10[Ge(SiMe₃)₃]₄}2−. The synthesis of diverse derivatives gives the opportunity to check the influence of the substituent for further investigations of metalloid tin cluster compounds.

(Multi-)Metallic Cluster Growth

This review article provides a survey of contemporary investigations on main group metal cluster formation, addressing homo- and heterometallic clusters (including small numbers of transition metal atoms), with or without an external ligand shell, thereby excluding clusters with non-metal atoms as bridging ligands. Most of the studies reflected herein represent insights into the formation of intermediates from the starting material, or the final cluster formation from established intermediates. In rare cases, the entire process was suggested as a result of comprehensive, multi-method elucidations. The article is to be understood as a state-of-the-art report, as the subject matter is currently a rising field of research, which is still in its infancy, despite some early activities that date back to the 1980s. At the same time, the article intends to point toward both the importance and the feasibility of according studies, in order to encourage researchers to gain even more knowledge in this field. Only deep understanding of cluster formation will allow for design, and ultimately control, of their syntheses, with the long-term goal of their optimization and purposeful application in catalysis or novel material synthesis.

[Hyp-Au-Sn9(Hyp)3-Au-Sn9(Hyp)3-Au-Hyp]-: the longest intermetalloid chain compound of tin

The reaction of the metalloid tin cluster [Sn₁₀(Hyp)₄]^2- with (Ph₃P)Au-SHyp (Hyp = Si(SiMe₃)₃) gave an intermetalloid cluster [Au₃Sn₁₈(Hyp)₈]^-1, which is the longest intermetalloid chain compound of tin to date. 1 shows a structural resemblance to binary AuSn phases, which is expected for intermetalloid clusters.

Reductive Elimination of Hydrogen from Bis(trimethylsilyl)methyltin Trihydride and Mesityltin Trihydride

Alkyltin trihydride [(Me₃ Si)₂ CHSnH₃ ] was synthesized and the reductive elimination of hydrogen from this species was investigated. A methyl-substituted N-heterocyclic carbene reacts with the organotrihydride in dependence on stoichiometry and solvent to give a series of products of the reductive elimination and dehydrogenative tin-tin bond formation. Besides characterization of the carbene adduct of the alkyltin(II) hydride, a Sn₄ chain was also isolated, encompassing two stannyl-stannylene sites, which are stabilized each as NHC-adducts. Complete dehydrogenation resulted to give either a carbene-stabilized distannyne or a metalloid Sn₉ -cluster salt. Reductive elimination of hydrogen was also achieved with an excess of diethylmethylamine to give the alkyltin(II) hydride as a Lewis base free tetramer [(RSnH)₄ ]. The method of cluster formation at low temperatures by hydrogen elimination was also transferred to the mesityl-substituted tin trihydride MesSnH₃ . In this case [(MesSn)₁₀ ], showing a [5]prismane structure, was isolated in good yield and characterized. NMR spectroscopic features of the propellane-type cluster [Trip₆ Sn₆ ] are reported.

Synthesis and solid state structure of a metalloid tin cluster [Sn10(trip8)]

The Mg(i) compound (LMg)₂ reacts with (trip₂Sn)₂ with formation of the metalloid Sn₁₀trip₈ cluster 1, which contains Sn atoms in the formal oxidations states 0, +I and +II, while the stronger Mg(i) reductant (L′Mg)₂ yielded elemental tin. The reaction demonstrates the promising potential of Mg(i) compounds to serve as soluble reductants for cluster synthesis.

{Sn10 [Si(SiMe3 )3 ]4 }(2-) : A highly reactive metalloid tin cluster with an open ligand shell

The reaction of a Sn(I) Cl solution with LiSi(SiMe3 )3 gave the anionic metalloid tin cluster {Sn10 [Si(SiMe3 )3 ]4 }(2-) (7) in good yield. The arrangement of the ten tin atoms in the cluster core can be described as a distorted centaur polyhedron. Quantum chemical calculations suggest that there are 26 bonding electrons in the cluster core, which may be described as an arachno cluster in agreement with Wade's rules. NMR and mass spectrometric investigations showed that 7 is highly reactive, which may be due to the open ligand shell. The easily available tin atoms in 7 thereby open the door to further subsequent reactions, in which 7 may act as a building block to larger cluster aggregates.

Si(SiMe3)2SiPh3 - a ligand for novel sub-valent tin cluster compounds

For the synthesis of metalloid tin cluster compounds applying the disproportionation reaction of a Sn(i) halide, silyl ligands, especially the symmetric Si(SiMe3)3 has proven to be extremely useful. Silyl ligands of lower symmetry where e.g. one SiMe3 group is substituted with SiPh3 are thereby unexplored, although the synthesis of the anionic silyl precursors is quite easy, referring to previously described methods. Here the synthesis of the silanide [Si(SiMe3)2(SiPh3)](-) as its potassium () as well as its lithium salt () in excellent yield is presented. proved to be a suitable starting material for the synthesis of subvalent tin compounds as shown by the reaction with tin halides in oxidation state +2 (SnCl2) and +1 (SnCl); i.e. on the one hand the anticipated stannide [Sn(Si(SiMe3)2SiPh3)2Cl](-) could be isolated and on the other hand the unexpectedly partly substituted ring compound Cl4Sn4[Si(SiMe3)2SiPh3]4 is obtained. As no elemental tin is formed during the reaction with SnCl, metalloid tin clusters may be present in solution too, which is supported by the nearly black color of the reaction mixture, showing that might be a suitable ligand for the synthesis of such cluster compounds.