Reactivity of [Ge₉{Si(SiMe₃)₃}₃]⁻ Towards Transition‐Metal M²⁺ Cations: Coordination and Redox Chemistry

Abstract

Recently the metalloid cluster compound [Ge Hyp ] (1; Hyp=Si(SiMe ) ) was oxidatively coupled by an iron(II) salt to give the largest metalloid Group 14 cluster [Ge Hyp ]. Such redox chemistry is also possible with different transition metal (TM) salts TM (TM=Fe, Co, Ni) to give the TM complexes [Fe(dppe) ][Ge Hyp ] (3; dppe=1,2-bis(diphenylphosphino)ethane), [Co(dppe) ][Ge Hyp ] (4), [Ni(dppe)(Ge Hyp )] (5) and [Ni(dppe) (Ge Hyp )] (6). Such a redox reaction does not proceed for Mn, for which a salt metathesis gives the first open shell [Hyp Ge -M-Ge Hyp ] cluster (2; M=Mn). The bonding of the transition metal atom to 1 is also possible for Ni (e.g., compound 6), in which one or even two nickel atoms can bind to 1. In contrast to this in case of the Fe and Co compounds 3 and 4, respectively, the transition-metal atom is not bound to the Ge core of 1. The synthesis and the experimentally determined structures of 2-6 are presented. Additionally the bonding within 2-6 is analyzed and discussed with the aid of EPR measurements and quantum chemical calculations.

An Isolable Bis(silylene)-Stabilized Germylone and Its Reactivity

“…The Ge–Ge distance is 2.4695(14) Å, which is above the range of a GeGe double bond (2.26–2.39 Å), ,,, and the Ni–Ge bond distances [2.4245(17) and 2.4431(17) Å] are significantly larger than that in the germylene-Ni complexes (average 2.25 Å). , In line with these structural data, compound 7 could be described as a bis­(NHSi)-stabilized Ge 2 Ni complex bearing a Ge I –Ge I –Ni II metallacycle; the latter results through reductive coupling of two Ge 0 atoms on the Ni 0 center, which, apparently, is favored over the formation a [η 2 -(digermene)]­Ni 0 π complex . To the best of our knowledge, Ge 2 Ni metallacyclic motifs were observed in Ge n cluster-Ni complexes ( n = 5, 9, 10, 13); that is, 7 is the first molecular Ge 2 Ni II complex.…”

Eclipsed- and Staggered-[Ge18Pd3{EiPr3}6]2– (E = Si, Sn): Positional Isomerism in Deltahedral Zintl Clusters

“…The same compound, but in much lower yield, was originally synthesized by the so-called subhalide approach wherein a metastable GeBr generated at 1550 °C is reacted with LiHyp at −78 °C . The hypersilylated species have been, in turn, studied for their reactivity to add a fourth substituent, to coordinate to transition metals, to aggregate, to add cluster atoms, etc. − In addition, similar heterogeneous reactions have produced clusters that are trisubstituted with other silyl-based substituents, thus demonstrating the versatility and capabilities of the proposed synthetic approach. − …”

Derivatization of Phosphine Ligands with Bulky Deltahedral Zintl Clusters—Synthesis of Charge Neutral Zwitterionic Tetrel Cluster Compounds [(Ge9{Si(TMS)3}2)tBu2P]M(NHCDipp) (M: Cu, Ag, Au)

“…However, recently a rational synthesis route for [Ge 9 {Si­(TMS) 3 } 3 ] − was reported, yielding the tris-silylated cluster in a large scale by the heterogeneous reaction of K 4 Ge 9 with Si­(TMS) 3 Cl in acetonitrile or thf . This novel route has led to a prosperous subsequent chemistry of [Ge 9 {Si(TMS) 3 } 3 ] − , obtaining a series of transition metal-bridged cluster dimers [M­(Ge 9 R 3 ) 2 ] n − (R: Si­(TMS) 3 ), − and 4-fold substituted clusters bearing transition metal organyl fragments as fourth group attached to the cluster [R x M(Ge 9 R 3 )] n − . − ,, Additionally, reactions of [Ge 9 {Si(TMS) 3 } 3 ] − with main group element compounds resulted in the introduction of [SnR 3 ] + (R: Ph, Me, n Bu) groups, , or in the formation of an additional Tl + vertex, and an ethyl group was introduced by reacting the tris-silylated cluster with bromoethane . Furthermore, other silyl groups were introduced at [Ge 9 ] affording the silylated clusters [Ge 9 R 3 ] − (R: Si­(TMS) 2 (SiPh 3 ), SiPh 3 , Si­( i Bu) 3 , Si­( i Pr) 3 , SiEt 3 , SiH t Bu 2 ), ,− and a similar stannyl decorated cluster (R: Sn­( i Pr) 3 ) was obtained analogously .…”