Mono- and Dinuclear Germapalladacycles Obtained via the Ge−Ge Bond Forming Reactions Promoted by Palladium Complexes

Abstract

Heating a toluene solution of bis(germyl)palladium complex [Pd(GeHPh2)2(dmpe)] (2) (dmpe = 1,2-bis(dimethylphosphino)ethane) at 70 °C produced a mixture of dipalladium complexes, one with bridging digermene and germylene ligands, [{Pd(dmpe)}2(μ-GePh2)(μ-Ge2Ph4)] (3), and also a mononuclear tetragermapalladacyclopentane, [Pd(GePh2GePh2GePh2 GePh2)(dmpe)] (4), in 92:8 molar ratio, respectively. The reaction of H2GePh2 with 2 in 10:1 molar ratio formed complex 4 as the main product (3:4 = 4:96). Complexes 3 and 4 were isolated from the above reactions and characterized by X-ray crystallography and NMR spectroscopy. Complex 3 reacted with H2GePh2 (Pd:Ge = 1:10) at 80 °C to yield 4 quantitatively, whereas simple heating of 3 at the same temperature did not form 4 at all. Reaction pathways for the Ge−Ge bond formation are discussed.

Aryl Oligogermanes as Ligands for Transition Metal Complexes

“…In addition, several possible modes to bonding between the M and the group 14 ligand could be expected, each of them having a different impact on the σ‐conjugation. Compounds, containing a covalent bond between the E atom and a transition metal, are numerous (leading references for Si derivatives with M = rare earth metals; Ti, Zr, Hf; Ta; Cr, Mo, W; Fe; Pd; Pt; Au; for special interest to Ge derivatives for Hf, Zr; W, Cr; Pt;[9b], Pd; Au; for Sn derivatives with Ti;, Mo, W; Fe etc. ), but the present study is focusing on the different types of bonding, including derivatives in which the metal M fragment is connected through an organic group (η n ‐coordination).…”

Germa- and Stanna-closo-dodecaborate in Reaction with [PdCl2(Xantphos)]: P–C and B–H Bond Activation

“…The interatomic palladium–germanium distance of 2.338(1) Å is significantly shorter than the one we reported earlier in the case of the homoleptic complex [Et 3 MeN] 6 [Pd(GeB 11 H 11 ) 4 ] [2.416(1) Å] . In the range of published Pd–Ge bond lengths [2.3207(7)–2.887(1)Å] − the found value belongs to the group of shorter distances. Short Pd–Ge bond length were found in the three-coordinated species [PdGe{N(SiMe 3 ) 2 } 2 (PPh 3 ) 2 ] [2.3281(4) Å] and [PdGe{N(SiMe 3 ) 2 } 2 (PEt 3 ) 2 ] [2.330(5) Å], in which double-bond character between metal and ligand was discussed to be responsible for the short interactions .…”

Bond Formation and Coupling between Germyl and Bridging Germylene Ligands in Dinuclear Palladium(I) Complexes

“…Important metric parameters of the [Pd 2 Ge 4 ] moiety in 1 a and 2 a are summarized in Figure 1 b. The PdGe1 bond lengths in 1 a [2.3600(9) Å] and 2 a [2.3975(4) Å] are comparable to the PdGe bond lengths in mononuclear palladium complexes with germylene ligands, such as [(R 3 P) 2 PdGe{N(SiMe 3 ) 2 } 2 ] [R=Et: 2.330(5) Å; R=Ph: 2.3281(4) Å],17 and shorter than in other complexes with PdGe bonds [2.4259(2)–2.5024(4) Å] 4c. The complex 2 a contains a shorter Pd*Ge1 bond [2.4445(4) Å], and longer PdGe1 [2.3975(4) Å] and PdGe2 [2.5002(5) Å] bonds compared to those of 1 a [2.4634(9) Å, 2.3600(9) Å, and 2.4631(8) Å, respectively].…”