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With the hope of tuning structural and electronic properties of the metal chains by changing the N‐substituent group and P‐chiral configurations, a series of PNP bridged tetraphosphines, rac‐ and meso‐Ph2PCH2P(Ph)N(Ar)P(Ph)CH2PPh2 (Ar=4‐RC6H4, R=F (rac‐dpmppanF), CH3 (rac‐dpmppanMe), H (meso‐dpmppan), OMe (meso‐dpmppanOMe); Ar=2,4‐xylyl (rac‐dpmppanMe2)), were synthesized, and utilized to prepare the Pd4 and Pt2Pd2 chains with XylNC terminal ligands, [M4(rac‐dpmppanR)2(XylNC)2](PF6)2 (M4=Pd4, R=F (1F), Me (1Me); M4=Pt2Pd2, R=F (4F), Me (4Me)) and [M4(meso‐dpmppanR)2(XylNC)2](PF6)2 (M4=Pd4, R=H (6), OMe (6OMe); M4=PdPt2Pd, R=OMe (9OMe)). While the M4 metal chains with rac‐dpmppanR (R=H, F, Me) ligands showed only marginal effects on the tetranuclear metal chains, the meso stereoisomer of meso‐dpmppanOMe afforded a new series of Pd4 (6OMe), PtPd3 (7OMe), PtPd2Pt (8OMe), PdPt2Pd (9OMe), Pt3Pd (10OMe), and Pt4 (11OMe) chains that exhibited a characteristic electronic absorption band tunable by the number and positions of incorporated Pt atoms from 628 nm to 473 nm. Especially, 11OMe is the first example of Pt4 chains supported by tetraphosphines. The coordinatively unsaturated Pd4 strings, [Pd4(rac‐dpmppan)2(CH3CN)](BF4)2 (12) and [Pd4(meso‐dpmppanOMe)2](BF4)2 (13), were also synthesized and 12 was utilized in axial ligand exchange reactions with PPh2Me, and PPh3 to disclose their successive incorporation into [Pd4(rac‐dpmppan)2(L)2](BF4)2 (L=PPh2Me (14 a), PPh3 (14 b)) and remarkable red‐shift (713–718 nm) of the HOMO‐LUMO transition of the Pd4 chains. The linear Pd4, PtnPd4‐n (n=1–3), and Pt4 complexes obtained in the present study could be useful 1D building blocks for assembling through metal−metal interaction. [ABSTRACT FROM AUTHOR]

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 Ph2SiH2 results in the formation of a tetranuclear complex with silyl and hydride ligands at the Pt center, [PtH(SiPh2H){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 29Si 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. [ABSTRACT FROM AUTHOR]

By using a chiral tetraphosphine, rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane ( rac-dpmppm), linear octapalladium chains were synthesized as discrete molecules of [Pd8(μ- rac-dpmppm)4L2](BF4)4 (L=CH3CN, dmf, XylNC), [Pd8(μ- rac-dpmppm)4](BF4)4, and [Pd8(μ- rac-dpmppm)4(Cl)2](BF4)2, which are stable in the solution states and characterized by spectroscopic and crystallographic methods to reveal the octapalladium chains supported by homochiral four tetraphosphines. Variable-temperature NMR studies for a 1:1 mixture of [Pd8(μ- rac-dpmppm)4(dmf)2](BF4)4 and [Pd8(μ- meso-dpmppm)4(dmf)2]-(BF4)4 in [D7]DMF revealed that the Pd8 chains were dissociated at higher temperature ( T≈140 °C) into the Pd4 units of {Pd4(μ- rac-dpmppm)2}2+ and {Pd4(μ- meso-dpmppm)2}2+, and they were thermodynamically self-aligned to restore the Pd8 chains at lower temperature ( T<60 °C), through perfect chiral self-recognition between the stereogenic tetrapalladium units. [ABSTRACT FROM AUTHOR]

A linear tetraphosphine, meso-bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm) was used to synthesize linear octapalladium-extended metal atom chains as discrete molecules of [Pd8(μ-dpmppm)4](BF4)4 ( 1) and [Pd8(μ-dpmppm)4L2](BF4)4 (L=2,6-xylyl isocyanide (XylNC; 2), acetonitrile ( 3), and N,N-dimethylformamide (dmf; 4)), which are stable in the solution states and show interesting temperature-dependent photochemical properties in the near IR region. Variable temperature NMR studies demonstrated that at higher temperature T≈140 °C the Pd8 chains were dissociated into Pd4 fragments, which were thermodynamically self-aligned to restore the Pd8 chains at lower temperature T<60 °C. The coldspray ionization mass spectra suggested a possibility for further aggregation of the linear tetrapalladium units. [ABSTRACT FROM AUTHOR]

Reports on the direct synthesis of binuclear palladium complexes containing phenyl-substituted cyclopentadienyl groups (C5Hc-nPhm, n=3-5) which are characterized by X-ray crystallography. Characterization of palladium and platinum clusters of isocyanides; Metal-metal interaction of binuclear palladium (I) complexes.

Investigates the reaction of PdCl2(RNC)2 where RNC = isocyanide, with lithium indenyl which gave binuclear palladium complexes Pd2(mu-eta3-In)2(RNC)2. Characterization by elemental analysis, X-ray crystallography and various spectroscopic techniques; Pd-Pd bond lengths.

Reports on the controlled-potential electrolysis on mononuclear palladium(II) complexes containing aromatic isocyanide and diphosphine ligands. IR, electronic and NMR spectroscopies; X-ray crystallographic and extended X-ray absorption fine structure (EXAFS) analysis.

A complex with a planar hexagonal Pd4Ge3 core, [Pd{Pd(dmpe)}3(μ3-GePh2)3], was synthesized and characterized by X-ray and NMR measurements as well as by DFT calculations. 4-tert-Butylbenzenethiol converted the Pd4 complex into a hexapalladium complex, [{Pd3(μ-GePh2)2(μ-H)(μ3-GePh2(SC6H4tBu-4))}2(μ-dmpe)], composed of two Pd3Ge3 units bridged by a dmpe ligand. The addition of CuI or AgI to the Pd4 complex yielded [Pd(μ-MI){Pd(dmpe)}3(μ3-GePh2)3 ] (M = Cu, Ag), in which Cu or Ag bridges a Pd–Pd bond of the Pd4Ge3 core. The CuI adducts in solution undergo a pivot motion of the CuI on the surface of the Pd4Ge3 plane on the NMR time scale. [ABSTRACT FROM AUTHOR]