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A P‐stereogenic linear tetraphosphine tetraoxide, (R,R)‐ or (S,S)‐dpmppm(=O)4, was synthesized to prepare C2 dinuclear M(hfa)3 complexes (M=Eu, Tb, Y) as the first example of lanthanide(III) complexes with P‐chiral multidentate phosphine oxides. The mononuclear M(hfa)3 complexes (M=Eu, Y) with a P‐chiral diphosphine dioxide, tpdpb(=O)2, were also prepared, and comparison of their photophysical properties for the EuIII complexes revealed that significant chiral induction from the P‐chiral centers arises on the achiral M(hfa)3 units through intramolecular π‐π stacking constraint in the dinuclear system. [ABSTRACT FROM AUTHOR]

Reactions of Pd8 strings supported by meso‐Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 (meso‐dpmppm) ligands, [Pd8(meso‐dpmppm)4(L)2]4+ (L=CH3CN (1), XylNC (2)) with C60 resulted in the exclusive formation of unprecedented metal‐chain‐wired C60 bucky balls, [{Pd4(meso‐dpmppm)2(L)}2(C60)]4+ (L=CH3CN (11), XylNC (12)), in which a C60 fullerene is trapped in the central Pd–Pd junction, as unambiguously established by spectroscopic, X‐ray crystallographic, and theoretical techniques. The similar reaction of Pd8 strings supported by rac‐dpmppm, [Pd8(rac‐dpmppm)4(CH3CN)2]4+ (3) also afforded a racemic mixture of [{Pd4((R*,R*)‐dpmppm)2(CH3CN)}2(C60)]4+ (13) without scrambling the Pd4 fragments with (R,R)‐ and (S,S)‐dpmppm ligands. Consequently, those of enantiopure chiral Pd8 strings, [Pd8((R*,R*)‐dpmppm)4(CH3CN)2]4+, certainly afforded chiral bucky balls of [{Pd4((R*,R*)‐dpmppm)2(CH3CN)}2(C60)]4+ (13RR and 13SS), that exhibit mirror‐image circular dichroism spectra. The reactions of 1 and 2 were also applied for trapping a C70 fullerene to give 2 : 1 adducts of [{Pd4(meso‐dpmppm)2(L)}2(C70)]4+ (L=CH3CN (21), XylNC (22)). These results provide useful information for creating a platform to develop dimensionally and chirality controlled metal–carbon nanocomposite materials. [ABSTRACT FROM AUTHOR]

A new linear tetraphosphine containing a PNP phosphazane bridge, rac‐bis[(diphenylphosphinomethyl)phenylphosphino]phenylamine (rac‐dpmppan), was synthesized and utilized to support a series of Pd/Pt mixed metal tetranuclear chains, [Pd4−nPtn(μ‐rac‐dpmppan)2(XylNC)2](PF6)2 (XylNC=xylyl isocyanide; n=0: Pd4 (1), 1: PtPd3 (2), 2: PtPd2Pt (3), 2: Pt2Pd2 (4), 3: Pt2PdPt (5)), in which the number and positions of additional Pt atoms were successfully controlled depending on the respective synthetic procedures using transformations from 1 to 3 through 2 and from 4 to 5 by redox‐coupled exchange reactions. The 31P{1H} NMR and ESI mass spectra and X‐ray diffraction analyses revealed almost identical tetranuclear structures, with slight contraction of metal‐metal bonds according to incorporation of Pt atoms. The electronic absorption spectra of 1–5 exhibited characteristic bands at 635–510 nm with an energy propensity depending on the number and positions of Pt centres, which were assigned to HOMO (dσ*σσ*) to LUMO (dσ*σ*σ*) transition by theoretical calculations. The present results demonstrated that the electronic structures of Pd/Pt mixed‐metal tetranuclear complexes are finely tuned as orbital‐overlapping alloyed metal chains by atomically precise Pt incorporation in the Pd4 chain. [ABSTRACT FROM AUTHOR]

A copper hydride cluster [Cu8(μ-H)6(μ-dppm)5](PF6)2 (dppm=bis(diphenylphosphino)methane) was prepared from reaction of [CuH(PPh3)]6 with dppm in the presence of [Cu(CH3CN)4]PF6 and exhibited fluxional behaviors in solution where the hydrides and the phosphines are scrambling around the trans-bicapped octahedral Cu8 framework. The Cu8H6 complex showed facile reactivity with CO2 (1 atm, RT) to afford a tricopper complex, [Cu3(μ-H)(μ-O2CH)(μ-dppm)3]PF6, which could be developed to unprecedented hydrosilylation of CO2 catalyzed by multinuclear CuH species under mild conditions. [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 series of tetragold(I) complexes supported by tetraphosphine ligands, meso- and rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane ( meso- and rac-dpmppm) were synthesized and characterized to show that the tetranuclear AuI alignment varies depending on syn- and anti-arrangements of the two dpmppm ligands with respect to the metal chain. The structures of syn-[Au4( meso-dpmppm)2X]X′3 (X=Cl; X′=Cl ( 4 a), PF6 ( 4 b), BF4 ( 4 c)) and syn-[Au4( meso-dpmppm)2]X4 (X=PF6 ( 4 d), BF4 ( 4 e), TfO ( 4 f); TfO=triflate) involved a bent tetragold(I) core with a counter anion X incorporated into the bent pocket. Complexes anti-[Au4( meso-dpmppm)2]X4 (X=PF6 ( 5 d), BF4 ( 5 e), TfO ( 5 f)) contain a linearly ordered Au4 string and complexes syn-[Au4( rac-dpmppm)2X2]X′2 (X=Cl, X′=Cl ( 6 a), PF6 ( 6 b), BF4 ( 6 c)) and syn-[Au4( rac-dpmppm)2]X4 (X=PF6 ( 6 d), BF4 ( 6 e), TfO ( 6 f)) consist of a zigzag tetragold(I) chain supported by the two syn-arranged rac-dpmppm ligands. Complexes 4 d-f, 5 d-f, and 6 d-f with non-coordinative large anions are strongly luminescent in the solid state ( λmax=475-515 nm, Φ=0.67-0.85) and in acetonitrile ( λmax=491-520 nm, Φ=0.33-0.97); the emission was assigned to phosphorescence from 3[dσ*σ*σ*pσσσ] excited state of the Au4 centers on the basis of DFT calculations as well as the long lifetime (a few μs). The emission energy is predominantly determined by the HOMO and LUMO characters of the Au4 centers, which depend on the bent ( 4), linear ( 5), and zigzag ( 6) alignments. The strong emissions in acetonitrile were quenched by chloride anions through simultaneous dynamic and static quenching processes, in which static binding of chloride ions to the Au4 excited species should be the most effective. The present study demonstrates that the structures of linear tetranuclear gold(I) chains can be modified by utilizing the stereoisomeric tetraphosphines, meso- and rac-dpmppm, which may lead to fine tuning of the strongly luminescent properties intrinsic to the AuI4 cluster centers. [ABSTRACT FROM AUTHOR]

Copper hydride cluster Cu8(μ‐H)6(μ‐dppm)5](PF6)2 (dppm=bis(diphenylphosphino)methane) was prepared and characterized, and exhibited fluxional behaviors in solution where the hydrides and the phosphines are scrambling around the trans‐bicapped octahedral Cu8 framework. The Cu8H6 complex readily reacted with CO2 (1 atm, RT) to afford a trinuclear complex, [Cu3(μ‐H)(μ‐O2CH)(μ‐dppm)3]PF6. Both complexes also promoted catalytic hydrosilylation of CO2 under mild conditions, which is very unusual for Cu‐H clusters. More information can be found in the Communication by T. Tanase et al. on page 9457. [ABSTRACT FROM AUTHOR]

A copper hydride cluster [Cu8(μ-H)6(μ-dppm)5](PF6)2 (dppm=bis(diphenylphosphino)methane) was prepared from reaction of [CuH(PPh3)]6 with dppm in the presence of [Cu(CH3CN)4]PF6 and exhibited fluxional behaviors in solution where the hydrides and the phosphines are scrambling around the trans-bicapped octahedral Cu8 framework. The Cu8H6 complex showed facile reactivity with CO2 (1 atm, RT) to afford a tricopper complex, [Cu3(μ-H)(μ-O2CH)(μ-dppm)3]PF6, which could be developed to unprecedented hydrosilylation of CO2 catalyzed by multinuclear CuH species under mild conditions. [ABSTRACT FROM AUTHOR]