Search

A new series of cationic heterodinuclear complexes, [M1M2Cl2(meso‐dpmppp)(RNC)2]PF6 (M1=Ni, M2=Rh, R=tBu (1 a); M1=Pd, M2=Rh, R=tBu (2 a), Xyl (2 b); M1=Pt, M2=Rh, R=tBu (3 a), Xyl (3 b); M1=Pd, M2=Ir, R=tBu (4 a)), supported by a tetradentate phosphine ligand, meso‐Ph2PCH2P(Ph)(CH2)3P(Ph)CH2PPh2 (meso‐dpmppp), were synthesized by stepwise reactions of meso‐dpmppp with NiCl2 ⋅ 6H2O or MCl2(cod) (M=Pd, Pt), forming mononuclear metalloligands of [M1Cl2(meso‐dpmppp)], and with [M2Cl(cod)]2 (M2=Rh, Ir) and RNC (R=tBu, Xyl) in the presence of [NH4][PF6]. The related neutral PdRh complex, [PdRhCl3(meso‐dpmppp)(XylNC)] (5), was also prepared. The structures of 1–5 were determined by X‐ray analyses to contain two square planar d8 metal centers with face‐to‐face arrangement, where meso‐dpmppp supports M1 and M2 metal ions in cis/trans‐P,P coordination mode, combining cis‐{M1P2Cl2} and trans‐{M2P2(CNR)2} units. Complexes 1–4 showed an intence characteristic absorption around 422–464 nm derived from RhI→RNC MLCT transition (HOMO→LUMO+1), which are influenced by changing M1 (NiII, PdII, PtII) metal ions since HOMO composed of dσ* orbitals appreciably destabilized by changing M1 from Ni to Pd, and Pt. The electronic structures of 1 a–4 a were investigated on the basis of DFT calculations and NBO analyses to show weak but noticeable d8–d8 metallophilic interaction as empirical dispersion energy of 0.9–1.5 kcal/mol without M1–M2 covalent bonding interaction. In addition, 1–5 were utilized as catalysts for hydrosilylation of styrene, and the NiRh complex 1 a was found to show higher activity and chemo‐ and regioselectivity compared with 2–5. [ABSTRACT FROM AUTHOR]

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 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 series of the octapalladium chains supported by meso‐Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 (meso‐dpmppm) ligands, [Pd8(meso‐dpmppm)4(L)2](BF4)4 (L=none (1), solvents: CH3CN (2 a), dmf (2 b), dmso (2 c), RN≡C: R=Xyl (3 a), Mes (3 b), Dip (3 c), tBu (3 d), Cy (3 e), CH3(CH2)7 (3 f), CH3(CH2)11 (3 g), CH3(CH2)17 (3 h)) and [Pd8(meso‐dpmppm)4(X)2](BF4)2 (X=Cl (4 a), N3 (4 b), CN (4 c), SCN (4 d)), were synthesized by using 2 a as a stable good precursor, and characterized by spectroscopic (IR, 1H and 31P NMR, UV‐vis‐NIR, ESI‐MS) measurements and X‐ray crystallographic analyses (for 1, 2 a, b, 3 a, b, e, f, 4 a–d). On the basis of DFT calculations on the X‐ray determined structure of 2 b ([2b‐Pd8]4+) and the optimized models [Pd8(meso‐Ph2PCH2P(H)CH2P(H)CH2PH2)4(CH3CN)2]4+ ([Pd8Ph8]4+) and [Pd8(meso‐H2PCH2P(H)CH2P(H)CH2PH2)4(CH3CN)2]4+ ([Pd8H8]4+), with and without empirically calculating dispersion force stabilization energy (B3LYP‐D3, B3LYP), the formation energy between the two Pd4 fragments is assumed to involve mainly noncovalent interactions (ca. −70 kcal/mol) with four sets of interligand C−H/π interactions and Pd⋅⋅⋅Pd metallophilic one, while electron shared covalent interactions are almost canceled out within the Pd8 chain. All the compounds isolated are stable in solution and exhibit characteristic absorption at ∼900 nm, which is assignable to a spin allowed HOMO to LUMO transition, and shows temperature dependent intensity change with variable absorption coefficients presumably due to coupling with some thermal vibrations. The structures and electronic states of the Pd8 chains are found finely tunable by varying the terminal capping ligands. In particular, theoretical calculations elucidated that the HOMO‐LUMO energy gap is systematically related to the central Pd−Pd distance (2.7319(6)–2.7575(6) Å) by two ways with neutral ligands L (1, 2, 3) and with anionic ligands X (4), which are reflected on the NIR absorption energy of 867–954 nm. The isocyanide terminated Pd8 complexes (3) further reacted with excess of RNC (6 eq) to afford the Pd4 complexes, [Pd4(meso‐dpmppm)2(RNC)2](BF4)2 (13), and the cyclic voltammograms of 2 a (L=CH3CN), 3, and 13 (R=Xyl, Mes, tBu, Cy) demonstrated wide range redox behaviors from 2{Pd4}4+ to 2{Pd4}0 through 2{Pd4}2+↔{Pd8}4+, {Pd8}3+, and {Pd8}2+ strings. The oxidized complexes, [Pd4(meso‐dpmppm)2(RNC)3](BF4)4 (16), were characterized by X‐ray analyses, and the two‐electron reduced chain of [Pd8(meso‐dpmppm)4](BF4)2 (7) was analyzed by spectroscopic and electrochemical techniques and DFT calculations. Reactions of 2 a with 1 equiv. of aromatic linear bisisocyanide (BI) in CH2Cl2 deposited insoluble coordination polymers, {[Pd8(meso‐dpmppm)4(BI)](BF4)4}n (5), and interestingly, they were soluble in acetonitrile, 31P{1H} and 1H DOSY NMR spectra as well as SAXS curves suggesting that the coordination polymers may exist in acetonitrile as dynamically 1D self‐assembled coordination polymers comprising ca. 50 units of the Pd8 rod averaged within the timescale. [ABSTRACT FROM AUTHOR]

Copper hydride compounds have attracted interest in diverse fields as base metallic material in place of rare and noble metals, which have widely been utilized in hydrogenation catalysts, hydrogen storage, and electrochemical materials. Since the first report on the synthesis of copper hydride complex [Cu6H6(PPh3)6] in 1971, copper hydride reagents have been utilized in a variety of organic transformation. While well‐characterized copper hydride complexes have been long limited to a few examples, recently several research groups have reported the synthesis of phosphine‐stabilized copper hydride complexes with various metal‐frameworks and unique reactivity. Here we review recent progress on the synthesis and structures of copper hydride complexes supported by phosphine ligands, including di‐, tri‐, and tetraphosphines, and also describe their reactivity with CO2. [ABSTRACT FROM AUTHOR]

Reaction of [Cu(MeCN)4]BF4 with rac‐Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 (rac‐dpmppm) gave [Cu2(µ‐rac‐dpmppm)(MeCN)4](BF4)2 (1), and that of CuCl with rac‐dpmppm in the presence of 2,6‐xylyl isocyanide (XylNC) and NH4PF6 afforded [Cu2(µ‐rac‐dpmppm)(XylNC)4](PF6)2 (2). Complex 1 was converted by treatment with diimino ligands (N^N) to a series of CuI2 complexes, [Cu2(µ‐rac‐dpmppm)(N^N)2]2+ (N^N = phen (3), 4‐Mephen (4), 4,7‐Me2phen (5), 5,6‐Me2phen (6), 2,9‐Me2phen (7), 3,4,7,8‐Me4phen (8), 4,7‐Ph2phen (9), bpy (10), 4,4′‐Me2bpy (11), and 1,8‐naphtyridine (nap) (12)), where phen = 1,10‐phenanthroline and bpy = 2,2′‐bipyridyl. The isolated complexes were characterized by spectroscopic and X‐ray crystallographic analyses to reveal that two CuI ions are triply bridged by a rac‐dpmppm ligand in κ2,κ2 fashion resulting in robust Z‐form dicopper structures, where the Cu···Cu distances vary from 4.2 to 5.6 Å depending on the ancillary ligands through altering conformation of the fused six‐membered chelate rings. The bulky ligands of XylNC and 2,9‐Me2phen deform the conformation to boat (2) and twist boat (7) forms, leading to elongation of Cu···Cu separation (Cu···Cu = 5.3488(5) Å (2), 5.5681(6) Å (7)), and other non‐bulky ligands render them deformed chair forms with Cu···Cu = 4.2051(5) Å (8) to 4.7341(5) Å (10). The solution behaviors of 5 and 11 were examined by variable temperature 1H NMR measurements to show fluxional exchange of the two nitrogen atoms attaching to the tetrahedral Cu centers with ΔG‡ of 14 kcal/mol at room temperature. Photophysical properties of 3–12 were also investigated to show rapid fluorescence at 394–467 nm in CH2Cl2 solutions and phosphorescence at 582–608 nm in the solid states. Reaction of [Cu(MeCN)4]BF4 with rac‐dpmppm and NaBH4 in MeOH/CHCl3 afforded [Cu4(µ4‐H)(µ‐Cl)2(µ‐rac‐dpmppm)2]BF4 (13), in which two rac‐dpmppm ligands exhibited a new coordination mode of κ2,κ1,κ1 M3‐bridge to hold two {Cu2(µ‐Cl)(µ‐rac‐dpmppm)}+ units connected by a central µ4‐hydride. [ABSTRACT FROM AUTHOR]

Reaction of [Cu(MeCN)4]BF4 with rac‐Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 (rac‐dpmppm) gave [Cu2(µ‐rac‐dpmppm)(MeCN)4](BF4)2 (1), and that of CuCl with rac‐dpmppm in the presence of 2,6‐xylyl isocyanide (XylNC) and NH4PF6 afforded [Cu2(µ‐rac‐dpmppm)(XylNC)4](PF6)2 (2). Complex 1 was converted by treatment with diimino ligands (N^N) to a series of CuI2 complexes, [Cu2(µ‐rac‐dpmppm)(N^N)2]2+ (N^N = phen (3), 4‐Mephen (4), 4,7‐Me2phen (5), 5,6‐Me2phen (6), 2,9‐Me2phen (7), 3,4,7,8‐Me4phen (8), 4,7‐Ph2phen (9), bpy (10), 4,4′‐Me2bpy (11), and 1,8‐naphtyridine (nap) (12)), where phen = 1,10‐phenanthroline and bpy = 2,2′‐bipyridyl. The isolated complexes were characterized by spectroscopic and X‐ray crystallographic analyses to reveal that two CuI ions are triply bridged by a rac‐dpmppm ligand in κ2,κ2 fashion resulting in robust Z‐form dicopper structures, where the Cu···Cu distances vary from 4.2 to 5.6 Å depending on the ancillary ligands through altering conformation of the fused six‐membered chelate rings. The bulky ligands of XylNC and 2,9‐Me2phen deform the conformation to boat (2) and twist boat (7) forms, leading to elongation of Cu···Cu separation (Cu···Cu = 5.3488(5) Å (2), 5.5681(6) Å (7)), and other non‐bulky ligands render them deformed chair forms with Cu···Cu = 4.2051(5) Å (8) to 4.7341(5) Å (10). The solution behaviors of 5 and 11 were examined by variable temperature 1H NMR measurements to show fluxional exchange of the two nitrogen atoms attaching to the tetrahedral Cu centers with ΔG‡ of 14 kcal/mol at room temperature. Photophysical properties of 3–12 were also investigated to show rapid fluorescence at 394–467 nm in CH2Cl2 solutions and phosphorescence at 582–608 nm in the solid states. Reaction of [Cu(MeCN)4]BF4 with rac‐dpmppm and NaBH4 in MeOH/CHCl3 afforded [Cu4(µ4‐H)(µ‐Cl)2(µ‐rac‐dpmppm)2]BF4 (13), in which two rac‐dpmppm ligands exhibited a new coordination mode of κ2,κ1,κ1 M3‐bridge to hold two {Cu2(µ‐Cl)(µ‐rac‐dpmppm)}+ units connected by a central µ4‐hydride. [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]

The mononuclear complex [Ni(meppp)] {H2meppp = meso-1,3-bis[(2-mercaptoethyl)(phenyl)phosphino]propane} was used as an S-bidentate NiP2S2 metalloligand to prepare a series of NiIIMI complexes with various neutral ligands, namely, [Ni(μ-meppp)ML2]PF6 [M = Rh, L = 1/2cod (1a; cod = 1,5-cycloocatadiene), CO (1b), XylNC (1c; Xyl = 2,6-dimethylphenyl), P(OPh)3 (1d); M = Ir, L = 1/2cod (2a), CO (2b), XylNC (2c)]. The reactivities of 1 and 2 toward methyl iodide and tertiary hydrosilanes were examined. Complexes 1c, 2a, and 2b reacted with MeI to afford the oxidative addition products [Ni(μ-meppp)-M(L)2(Me)(I)]PF6 [M = Rh, L = XylNC (3c); M = Ir, L = 1/2cod (4a)] and [Ni(μ-meppp)Ir(CO)(Me)(I)2] (5). In the reactions with hydrosilanes, only 2c exhibited an interesting reactivity to afford the NiII(μ-H)IrIII silyl complexes [Ni(μ-meppp)(μ-H)-Ir(XylNC)2(Si)]PF6 [Si = SiEt3 (6a), SiMe2Ph (6b), SiMePh2 (6c), SiPh3 (6d)]. The reaction proceeded via the intermediate isomers [Ni(meppp)(μ-H)Ir(XylNC)2(Si)]PF6 (7); intermediate 7d (Si = SiPh3) was characterized and has an NiII(μ-H)IrIII silyl structure with the hydrido ligand nesting in the reverse side of the Ni(μ-S)2Ir pocket to that of 6d. These results demonstrated that the reactivities of the bis(thiolate)-bridged NiIIMI heterodinuclear complexes can be tuned by changing the metal ions and ancillary ligands. In addition, the S-bidentate NiP2S2 metalloligand [Ni(meppp)] plays an important role in the stabilization of the bridging hydrido ligand in both pockets of the NiII(μ-H)IrIII core owing to the flexibility of the hinged Ni(μ-SR)2Ir structure. [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]

Linear Triplatinum Tetrahydride Complex Supported by Triphosphine Ligands, [Pt3(µ-H)2(H)2(µ-dpmp)2](BF4)2 {dpmp = bis(diphenylphosphinomethyl)phenylphosphine} By treating [Pt6(µ-H)(H)2(µ-dpmp)4]BH4 [4, dpmp = bis(diphenylphosphinomethyl)phenylphosphine] with an excess amount of HBF4 in N,N-dimethylformamide (DMF), a triplatinum tetrahydride complex, [Pt3(µ-H)2(H)2(µ-dpmp)2](BF4)2 (5), was obtained in 51 % yield and was characterized by IR, UV/Vis, ¹H NMR, and 31P{¹H} NMR spectroscopy in addition to ESI mass spectrometry, X-ray crystallography, and DFT calculations. Complex 5 is composed of linear trinuclear platinum centers supported by two dpmp ligands, {Pt3(µ-dpmp)2}6+, which accommodate two terminal and two bridging hydrides in a HPtHPtHPtH zigzag structure. The hydride positions were deter-mined by DFT optimization with B3LYP/GD3BJ functionals. Variable-temperature ¹H{31P} NMR spectroscopy in [D7]DMF revealed that the bridging hydrides exhibit fluxional behavior and migrate along the Pt3 chain by switching the bridging site, whereas the terminal hydrides are not exchanged with the bridging ones. The present results suggest that the divalent linear triplatinum unit of {Pt3(µ-dpmp)2}2+ (Pt3 II), which is a building block to construct [Pt6(µ-H)(H)2(µ-dpmp)4]+ (4, Pt3 IIPt3 II), formally acts as a four-electron source to result in [Pt3(µ-H)2(H)2(µ-dpmp)2]2+ (5, Pt3 VI) through protonation. [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 SN n mixed-donor ligands [ n = 2: H2NC2H4SCH2-2-pyridyl (2-NSpy) ( 1a), H2NC2H4SCH2-4-pyridyl (4-NSpy) ( 1b), n = 3: 2-pyridylCH2NHC2H4SCH2-2-pyridyl (2-pyNSpy) ( 2), n = 4: (2-pyridylCH2)2NC2H4SCH2-2-pyridyl (2-py2NSpy) ( 3)] was utilized to support homo- and heterodinuclear complexes including Cp*MIII units (M = Rh, Ir; Cp* = pentamethylcyclopentadienyl). Reactions of [Cp*MCl2]2 with 2-pyNSpy ( 2), 2-py2NSpy ( 3), and 4-NSpy ( 1b) afforded homodinulear complexes, [(Cp*MCl)(2-pyNSpy)(Cp*MCl)](PF6)2 [M = Rh ( 5a), Ir ( 5b)], [(Cp*M)(2-py2NSpy)(Cp*MCl)](PF6)3 [M = Rh ( 6a), Ir ( 6b)], [(Cp*MCl)(4-NSpy)(Cp*MCl2)]Cl [M = Rh ( 8a), Ir ( 8b)]. Heterodinuclear complexes [(Cp*MCl)(4-NSpy)(Cp*M′Cl2)]Cl [M, M′ = Rh, Ir ( 8c), Ir, Rh ( 8d)] were prepared using mononuclear complexes [(Cp*MCl)(4-NSpy)]Cl [M = Rh ( 7a), Ir ( 7b)] reacted with [Cp*MCl2]2 (M = Ir, Rh), respectively. Complexes 5- 8 were characterized by X-ray crystallography to determine the configurations around the M, M′, S, and N centers. The solid-state structures of 6 are retained in acetonitrile solution whereas four diastereomers are generated in the case of 5 due to low stereoselectivity around the coordinated amine nitrogen atom, in contrast to the sulfur atom. Heterodinuclear complexes 8c, d are unstable in solution at 55 °C, readily affording mixtures of 8a- d via intra- and intermolecular coordination-site-exchange reactions of Cp*M fragments between the SN moiety and the py site. In order to evaluate the selectivity of Cp*M fragments for the SN and py coordination sites, several competitive reactions of [Cp*MCl2]2 (M = Rh, Ir) with H2NC2H4SCH2C6H5 (NSph) ( 4) and/or 4-methylpyridine (4-Mepy) were carried out to demonstrate predominant formation of iridium complexes 9b and 10b among [(Cp*MCl)(NSph)]Cl [M = Rh ( 9a), Ir ( 9b)] and [(Cp*MCl)(4-Mepy)]Cl [M = Rh ( 10a), Ir ( 10b)]. These reactions indicated higher affinity of the Cp*Ir fragment to both the NS and py sites relative to the rhodium analogue. [ABSTRACT FROM AUTHOR]

The reaction of Cu(NO3)2 ·3H2O with an N2O2 tetradentate amino alcohol, N, N-dibenzyl- N′, N′-bis(2-hydroxyethyl)ethylenediamine (H2L), afforded the mononuclear copper complex [Cu(H2L)(NO3)](NO3) ( 1), which has been used to construct a series of di-, tri-, and tetranuclear homo- and heterometallic complexes. Complex 1 dimerized in the presence of NEt3 to form the Cu2 complex [Cu2(HL)2](NO3)2 ( 2) by the deprotonation of one of the two hydroxy groups in the H2L ligand. The reaction of 1 with Cu(OCOH)2 in the presence of NEt3 afforded the Cu3 complex [Cu3(HL)2(OCOH)2](NO3)2 ( 5). The metalloligand {Cu(HL)}+ derived from 1 reacted with M(OAc)2 (M = Cu, Co, Zn, Ni) in the absence of NEt3 to form the asymmetric CuM dinuclear complexes [CuM(HL)(OAc)(NO3)2] [M = Cu ( 3a), Co ( 3b), Zn ( 3c), Ni ( 3d)], whereas in the presence of NEt3 a unit of M(OAc) was captured by two metalloligands to give the bent CuMCu trinuclear complexes [Cu2M(HL)2(OAc)2(NO3)](NO3) [M = Cu ( 4a), Co ( 4b), Mn ( 4c)], which were further transformed into the linear CuMCu trinuclear complexes [Cu3(HL)2{(PhO)2PO2}2](NO3)2 ( 7a) and [Cu2M(HL)2{(PhO)2PO2}2(MeOH)2](NO3)2 [M = Co ( 7b), Mn ( 7c)] with the aid of diphenyl phosphate bridging ligands. When (PhO)PO2(OH) was used as an auxiliary bridging ligand in the reaction of 1 with M(OAc)2 and NEt3, the Cu2M2 tetranuclear complexes [Cu2M2(HL)2{(PhO)PO3}2(NO3)2] [M = Co ( 8a), Zn ( 8b)] were synthesized. These results demonstrate that the mononuclear copper synthon with the N2O2 tetradentate amino alcohol ligand {Cu(H2L)}2+ generates the quite useful metalloligand {Cu(HL)}+ by the deprotonation of a hydroxy group, and subsequent reactions lead to the construction of a series of homo- and heterometal complexes containing Cu2, CuM (M = Cu, Co, Zn, Ni), bent-CuMCu (M = Cu, Co, Mn), linear-CuMCu (M = Cu, Co, Mn), and Cu2M2 (M = Co, Mn) cores in a systematic and selective manner. [ABSTRACT FROM AUTHOR]

A new linear hexaphosphine, rac-cis,cis,transbis{[( diphenylphosphinomethyl)phenylphosphinomethyl]- phenylphosphino}methane (P6), was synthesized and isolated as a pure isomer, confirmed by transforming to the corresponding phosphine sulfide. The methylene-bridged linear hexaphosphine readily organized flexible gold(I) and silver(I) hexanuclear chains, [M6(μ-P6)2]X6 (X6=(OTf)6, M= Au (1), Ag (2); X6=Cl2(PF6)4, M=Au (3)). The hexaphosphine also supported a tetrasilver(I) complex [Ag4(μ- P6)2](OTf)4 (4), which was readily transformed by treatment with AgOTf into 3, revealing a drastic alternation of the two P6 arrangement. The hexagold(I) chains exhibited a considerably red-shifted absorption (~410 nm) and emission (540-580 nm) to 1[5dσ* →6pσ] and from 3[5dσ* → 6pσ] excited states of the metal centers, respectively. The new linear hexaphosphine could be a useful tool to construct linear metal clusters as subnano building blocks. [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]

Reactions of meso-bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm) with CuI species in the presence of NaBH4 afforded di- and tetranuclear copper hydride complexes, [Cu2(μ-H)(μ-dpmppm)2]X ( 1) and [Cu4(μ-H)2(μ4-H)(μ-dpmppm)2]X ( 2) (X=BF4, PF6). Complex 1 undergoes facile insertion of CO2 (1 atm) at room temperature, leading to a formate-bridged dicopper complex [Cu2(μ-HCOO)(dpmppm)2]X ( 3). The experimental and DFT theoretical studies clearly demonstrate that CO2 insertion into the Cu2(μ-H) unit occurred with the flexible dicopper platform. Complex 2 also undergoes CO2 insertion to give a formate-bridged complex, [Cu4(μ-HCOO)3(dpmppm)2]X, during which the square Cu4 framework opened up to a linear tetranuclear chain. [ABSTRACT FROM AUTHOR]

The reactions of M(OAc)2 ·4H2O (M = Ni, Co) with three unsymmetrical amine-diol ligands RN(CH2CH2OH)(CH2CH2CH2OH) (H2 L n: n = 1, R = benzyl; n = 2, R = 4-methylbenzyl; n = 3, R = 2-naphthalenylmethyl) in the presence of NEt3 or pyridine in MeOH or BnOH gave the tetranuclear complexes [M4(H L n)2(OAc)6(MeOH)2] {M = Ni, n = 1 ( 1a), 2 ( 1b), 3 ( 1c); M = Co, n = 1 ( 4a), 2 ( 4b), 3 ( 4c)} and [M4(H L n)2(OAc)6(BnOH)2] {M = Ni, n = 1 ( 2a), 2 ( 2b), 3 ( 2c); M = Co, n = 1 ( 5a), 2 ( 5b), 3 ( 5c)}. When p-xylene-α,α′-diol was used instead of monoalcohols, the tetranuclear {M4O6} units were linked by p-xylene-α,α′-diol to form the 1D coordination polymers [M4(H L n)2(OAc)6( p-HOCH2C6H4CH2OH)] m {M = Ni, n = 1 ( 3a), 2 ( 3b); M = Co, n = 1 ( 6a), 2 ( 6b)}. The structures of 1- 6 were determined by X-ray crystallography and consist of centrosymmetrical tetranuclear {M4O6} face-shared defective double-cubane cores supported by two monodeprotonated (H L n)- ligands. The mixed-metal tetranuclear complexes [Ni2.2Co1.8(H L1)2(OAc)6(MeOH)2] ( 7) and [Mn1.7Ni2.3(H L1)2(OAc)5(OMe)2] ( 8) were also synthesized by using equimolar amounts of Ni2+ and M2+ (M = Co, Mn) ions. X-ray crystallographic and fluorescent analyses revealed that 7 is isomorphous with 1a and 4a and contains nonstoichiometric amounts of disordered Ni2+ and Co2+ ions in an average ratio of 2.2:1.8 with different occupancies for the two crystallographically independent metal centers. In contrast, 8 consists of a C2-symmetrical face-shared defective double-cubane {MII3MnIIIO6} core with a Ni/Mn ratio of 2.3:1.7; the amounts of Ni2+ and Mn2+ ions vary depending on the metal sites, and one of the C2 axial positions is exclusively occupied by Mn3+ ions. Detailed magnetostructural analyses on the nickel ( 1a, 2a, 3a) and cobalt ( 4a) complexes with appropriate spin-Hamiltonian models showed that both ferro- and antiferromagnetic spin exchange interactions were involved within the tetranuclear units, and their extent depends on the combination of the metal ions and the ligand systems in a delicate fashion. [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]

Cover Feature: Fine Tunable, Redox Active Octapalladium Chains Supported by Linear Tetraphosphines, Leading to Dynamically 1D Self-Assembled Coordination Polymers (Chem. Eur. J. 47/2021) Keywords: 1D dynamic coordination polymer; noncovalent interactions; palladium chain complexes; redox active metal chains; tetraphosphine EN 1D dynamic coordination polymer noncovalent interactions palladium chain complexes redox active metal chains tetraphosphine 12010 12010 1 08/23/21 20210819 NES 210819 B Dynamically 1D assembled linear Pd SB 8 sb chains b with bisisocyanide linkers are shown against a backdrop of contrails lit from below by the rising sun. 1D dynamic coordination polymer, noncovalent interactions, palladium chain complexes, redox active metal chains, tetraphosphine. [Extracted from the article]

Front Cover: Multinuclear Copper Hydride Complexes Supported by Polyphosphine Ligands (Eur. J. Inorg. B The Front Cover b shows a variety of multinuclear copper hydride complexes supported by polyphosphine ligands, some of which catalyze hydrogenation of CO SB 2 sb affording formate salts and dehydrogenation of formic acid into H SB 2 sb and CO SB 2 sb . Multinuclear copper hydride scaffolds would deserve a next frontier exploring new functions with green sustainable dihydrogen energy by cooperative effects of base metallic copper centers, and lead to atomically precise copper nanoparticles. [Extracted from the article]

Focuses on an azonia derivative of hexahelicene. Replacement of an outer bridgehead carbon of hexahelicene; Geometrical change in the helical structure.

Invited for the cover of this issue is the group of Tomoaki Tanase at Nara Women's University, Japan. The cover image shows a dinuclear copper(I) complex triply bridged by rac‐dpmppm with a series of diimino ligands as a "dicopper firefly" that switches its luminescence mechanisms to emit rapid fluorescence in dichloromethane solution and 3MLCT phosphorescence in the solid state. [ABSTRACT FROM AUTHOR]

B The Front Cover b shows dinuclear copper(I) complexes triply bridged by a tetraphosphine I rac i -dpmppm ligand in Z-form with a series of diimino ligands, which emit rapid fluorescence from loosely coordinated diimino ligands in CH SB 2 sb Cl SB 2 sb solution and SP 3 sp MLCT phosphorescence in the solid state. The "dicopper firefly" switches the luminescence mechanisms by fluxional flipping of the diimino ligands. The "dicopper firefly" switches the luminescence mechanisms by fluxional flipping of the diimino ligands. [Extracted from the article]

Invited for the cover of this issue is the group of Tomoaki Tanase at Nara Women's University, Japan. The cover image shows a dinuclear copper(I) complex triply bridged by rac‐dpmppm with a series of diimino ligands as a "dicopper firefly" that switches its luminescence mechanisms to emit rapid fluorescence in dichloromethane solution and 3MLCT phosphorescence in the solid state. [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]

The crystal structure of the title compound, C9H8N+·PF6−, was measured at 145 K. The cationic part of the compound has crystallographically imposed 2/ m symmetry with N/C disorder. [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]

In the title compound, [Pt2(μ-C14H16N3O)2(NH3)4](ClO4)6·2H2O, the diplatinum(II) cation is found to be a head-to-tail isomer. The intradimer Pt—Pt distance [3.0304 (7) Å] is much shorter than the value of 3.0852 (13) Å reported for the analogous cis-diammineplatin­um(II) dimer bridged by 2-( N′-methyl-4,4′-bipyridinium-1-yl)­acetamidates [Sakai, Ikuta, Tsu­bomura, Kato, Yokoyama, Kajiwara & Ito (2003). Acta Cryst. E 59, m780–m783], showing that the electron density at the metal centers is higher in the title system than in the previously reported system. The shortest interdimer Pt⋯Pt distance is 8.4585 (8) Å. [ABSTRACT FROM AUTHOR]