Multinuclear palladium compounds containing palladium centers ligated by five silicon atoms

Synthesis of a homoleptic tris(silylene)-palladium(0) complex and a silylyne-bridged tetranuclear palladium cluster

We report the reactions of an iminophosphonamido-silylene (1) with different palladium complexes. The reaction of 1 with [Pd(PPh3)4] furnished a homoleptic tris(silylene)-palladium(0) complex. In contrast, treatment of 1 with [PdMe2(tmeda)] led to the unprecedented formation of a non-planar μ3-silylyne-bridged tetranuclear palladium cluster that contains palladium atoms in different oxidation states.

Trapping of two mononuclear silyl platinum(ii)/palladium(ii) complexes and a unique dinuclear bis(μ2-disilene)(silyl)nickel(ii) complex

Two rare mononuclear bis(silyl)platinum(ii)/palladium(ii) intermediates and an unprecedented dinuclear bis(μ₂-disilene)(silyl)nickel(ii) complex have been trapped and prepared.

Bimolecular fusion of [Pd3(μ-CN-C6H3Me2-2,6)3(CN-C6H3Me2-2,6)3] induced by Ph2GeH2: formation of the redox-active Pd6Ge2 complex

The reaction of Ph₂GeH₂ with a planar tripalladium(0) complex, [Pd₃(μ-CN-C₆H₃Me₂-2,6)₃(CN-C₆H₃Me₂-2,6)₃], selectively afforded a hexagonal bipyramidal Pd₆Ge₂ complex, [Pd₆(μ-GePh₂)₂(CN-C₆H₃Me₂-2,6)₈(μ-CN-C₆H₃Me₂-2,6)₂]. The molecule is stabilized by bridging coordination of isonitrile and GePh₂ ligands, although all the Pd-Pd bonds are weak, as revealed by DFT calculations. The resulting complex undergoes two successive redox processes at E_1/2 = -1.35 and -1.03 V (vs. Fc⁺/Fc), which correspond to the stepwise oxidation of the Pd(0)₆ complex.

Isolation of two bis(silyl)nickel complexes with Si–Si bond formation in a single-crystal-to-single-crystal fashion

Two unique silyl nickel complexes that generate two new Si–Si single bonds have been prepared unprecedentedly, which exhibit reversible single-crystal-to-single-crystal transformations upon the removal and rebinding of the coordinating PEt₃ molecule.

Planar PtPd3 Complexes Stabilized by Three Bridging Silylene Ligands

A heterobimetallic PtPd₃ complex supported by three bridging diphenylsilylene ligands, [Pt{Pd(dmpe)}₃ (μ₃ -SiPh₂ )₃ ] (1, dmpe=1,2-bis(dimethylphosphino)ethane), has been synthesized from mononuclear Pd and Pt complexes. The hexagonal core composed of Pt, Pd, and Si atoms is slightly larger than that of the tetrapalladium complex, [Pd{Pd(dmpe)}₃ (μ₃ -SiPh₂ )₃ ] (2). Reaction of PhSiH₃ with complex 1 in the presence and absence of Ph₂ SiH₂ results in the formation of a tetranuclear complex with silyl and hydride ligands at the Pt center, [PtH(SiPh₂ H){Pd(dmpe)}₃ (μ₃ -SiHPh)₃ ] (3), and an octanuclear complex, [{Pt{Pd(dmpe)}₃ (μ₃ -SiHPh)₃ }₂ (κ² -dmpe)] (5), respectively. Both M-Si (M=Pt, Pd) bond lengths and the ²⁹ Si NMR chemical shifts of 1 and 2 are located between those of mononuclear late transition-metal complexes with a silylene ligand and complexes with donor-stabilized silylene ligands. CuI and AgI adducts of 1 and 2, formulated as [M(μ-M'I){Pd(dmpe)}₃ (μ₃ -SiPh₂ )₃ ] (M=Pt, Pd; M'=Cu, Ag), undergo elimination of CuI (AgI) and regenerate the tetrametallic complexes upon heating or addition of a chelating diphosphine. Elimination of AgI from 2-AgI occurs more rapidly than elimination of CuI from 2-CuI, as determined from the results of kinetics experiments.

Disilametallacyclic chemistry for efficient catalysis

Disilametallacyclic species of late transition metals behave as key intermediates for efficient catalytic reactions proceeding through new mechanisms.

A triangular triplatinum(0) complex with bridging germylene ligands: insertion of alkynes into the Pt–Ge bond rather than the Pt–Pt bond

A triangular triplatinum(0) complex with bridging germylene ligands was prepared and fully characterized. The Pt₃Ge₃ core is bonded with electron-releasing GePh₂ and PMe₃ ligands. Insertion of alkyne into the Pt–Ge bonds results in the formation of germaplatinacyclic compounds.