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The dynamical functions of molecular metal chains, that could be derived from unique physical and chemical properties coupled with self-assembly of metal chain components, have largely been unexplored, and this review paper focuses on the dynamic behaviours of Pd chains supported by linear tetraphosphines, meso- and rac-Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 recently reported, and the current development on fine-tuning of metal chains by introducing heterometal atoms, i.e. heterometallic molecular metal chains, that are considered as promising dynamical components in the next generation. [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]

The linear Pd8 complex supported by tetraphosphines reacted with HBF4 to give an unprecedented linear tetrapalladium complex with a terminal hydride, which promoted electrocatalytic hydrogen formation from HBF4 in acetonitrile. The 1D coordination polymer of Pd8 chain confined within Nafion film was applied to the electrocatalytic H2 formation. [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]

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]

Abstract Reaction of [IrCl(CO)(PPh 3) 2 ] with meso -bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso -dpmppm) afforded a mononuclear IrI complex, [Ir(meso- dpmppm−κ3)(CO) 2 ]Cl (1), which showed excellent reactivity towards HX, H 2 , HCOOH, and R 3 SiH to yield a series of IrIII hydride complexes, [IrH(meso -dpmppm−κ3)(CO) 2 ]X 2 (X = Cl (2), PF 6 (2*)), [Ir(H) 2 (meso -dpmppm−κ3)(CO)]Cl (4), and [IrH(SiR 3)(meso -dpmppm−κ3)(CO)]Cl (R 3 = Me 2 Ph (5a), Ph 2 H (5b)). The hydride IrIII complexes with isocyanides, [IrH(meso- dpmppm−κ3)(RNC) 2 ](PF 6) 2 (R = Xyl (2,6-xylyl) (3a), Mes (2,4,6-mesityl) (3b), Cy (cyclohexyl) (3c), t Bu (tert -butyl) (3d)), were also prepared by reacting [IrCl(cod)] 2 with meso -dpmppm and RNC in the presence of NH 4 PF 6. Complexes 2 – 5 were characterized by 1H and 31P NMR and ESI−MS spectroscopies and X-ray diffraction analyses (3a , 4 , 5a , b) to have distorted octahedral IrIII structures supported by a meso -dpmppm in meridional mode as an unsymmetrical PPP −κ3 pincer ligand, coordinating with two outer and one inner phosphorus atoms to form fused six- and four-membered chelate rings and bearing an uncoordinate inner phosphine unit. The terminal hydride occupied the axial open site surrounded by the equatorially oriented phenyl groups of meso -dpmppm and is trans to the carbonyl (2 , 4) and isocyanide ligands (3) nested in the closed site with respect to the {Ir(meso -dpmppm−κ3)} pincer plane. The remaining equatorial site is coordinated by CO (2), RNC (3), hydride (4), and silyl (5) ligand. These structural features demonstrated that oxidative additions of H+, H 2 , and R 3 SiH occurred at the axial open site of 1. The uncoordinate inner phosphine of 1 is readily reacted with [Cp*IrCl 2 ] 2 to give [Ir(μ− meso -dpmppm−κ3)(η5−Cp*IrCl 2)(CO) 2 ]Cl (1 ∙Cp*IrCl 2 , Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl), which further transformed by oxidative addition of H 2 and HCl to [Ir(H) 2 (μ− meso -dpmppm−κ3)(η5−Cp*IrCl 2)(CO)]Cl (4 ∙Cp*IrCl 2) and [IrH(μ− meso -dpmppm−κ3) (η5−Cp*IrCl 2)(CO) 2 ]Cl 2 (2 ∙Cp*IrCl 2), respectively, and however addition of bulky Me 2 PhSiH resulted in a disproportionation mixture of [IrH(Me 2 PhSi)(μ− meso -dpmppm−κ3)(η5-Cp*IrCl 2)(CO)]Cl (5a ∙Cp*IrCl 2) as well as 4 ∙Cp*IrCl 2 , indicating an allosteric influence by attaching Cp*IrCl 2 unit on the uncoordinate phosphine of the {Ir(meso -dpmppm−κ3)} unsymmetric pincer unit in 1. Graphical abstract Image 1 Highlights • The tetraphosphine meso -dpmppm holds an Ir center as an unsymmetric pincer ligand. • An IrI complex with meso -dpmppm underwent oxidative addition of H+, H 2 , and R 3 SiH. • A series of IrIII hydride complexes with meso -dpmppm were isolated and characterized. [ABSTRACT FROM AUTHOR]

Abstract A linear tetraphosphine meso -bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso -dpmppm), was utilized to prepare a PtI dinuclear complex, [Pt 2 (μ− meso -dpmppm−κ2,κ1)(XylNC) 3 ](PF 6) 2 (2), which was derived from reaction of [PtII(meso -dpmppm−κ3)(XylNC)](PF 6) 2 (1) with 1/3 equiv. of [Pt 3 (XylNC) 6 ]. Treatment of 2 with 1/3 equiv. of [Pt 3 (XylNC) 6 ] gave an A-frame Pt 3 complex, [Pt 3 (μ− meso -dpmppm−κ2,κ1)(XylNC) 5 ](PF 6) 2 (3), demonstrating that a meso -dpmppm ligand effectively support the expansion of platinum nuclearity from Pt2+ through {Pt 2 }2+ to {Pt 3 }2+ cores in stepwise fashion. Reaction of 2 with 1 equiv. of meso -dpmppm afforded [Pt 2 (μ− meso -dpmppm−κ2,κ1) 2 ](PF 6) 2 (4), which would not react with [Pt 3 (XylNC) 6 ], and in contrast, treatment of 3 with excess of [Pt 3 (XylNC) 6 ] gave birth to a decanuclear platinum complex, [Pt 10 (μ− meso -dpmppm−κ2,κ1,κ1) 2 (XylNC) 18 ](PF 6) 6 , (5), comprised of a linear Pt 4 chain {Pt 4 (XylNC) 8 }2+ terminated by two Pt 3 A-frame units of {Pt 3 (μ− meso -dpmppm−κ2,κ1,κ1)(XylNC) 5 }2+, which is an interesting nano-ordered Pt cluster constructed with small size multinuclear building blocks, and notably contains the longest metal–metal bonded Pt chain without any bridging ligands. Graphical abstract Image 1 Highlights • An unprecedented decanuclear Pt complex was successfully synthesized. • The Pt 10 complex consists of a Pt 4 chain terminated by two A-frame Pt 3 units. • The Pt 4 chain is the longest molecular Pt chain without any bridging ligands. [ABSTRACT FROM AUTHOR]

Abstract Reaction of [PtCl 2 (cod)] with a tetraphosphine meso -bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso -dpmppm), afforded mononuclear PtII complexes, [PtCl(meso -dpmppm−κ3)]X (X = Cl (1a), PF 6 (1b)); the meso -dpmppm ligand coordinates to the PtII ion tightly with two outer and one inner phosphorus atoms to form fused six- and four-membered chelate rings which is regarded as an asymmetric PPP pincer ligand bearing an uncoordinate inner phosphine unit. Complex 1 readily reacted with RNC in the presence of NH 4 PF 6 to afford [Pt(meso -dpmppm−κ3)(RNC)](PF 6) 2 (R = Xyl (2a), Cy (2b), t Bu (2c)). When 2a and 2b were reacted with excess of benzylamine (BnNH 2), N -acyclic carbene complexes, [Pt(meso -dpmppm−κ3){C(NHR)(NHBn)}](PF 6) 2 (R = Xyl (3a), Cy (3c)), were obtained, and a similar treatment of 2a with n -octylamine (C 8 H 17 NH 2) afforded [Pt(meso -dpmppm−κ3)- {C(NHXyl)(NHC 8 H 17)}](PF 6) 2 (3b). In contrast, complex 2c was transformed into a cyanide complex, [Pt(CN)(meso -dpmppm−κ3)]PF 6 (4), through N C( t Bu) bond cleavage when heated at 80 °C with BnNH 2 or PhNH 2. Complexes 1 – 4 were characterized by 1H and 31P NMR and ESI-MS spectroscopies and X-ray diffraction analyses. The uncoordinate inner phosphine of 1b is readily reacted with [Cp*MCl 2 ] 2 to give heterodimetallic complexes, [PtCl(η5-Cp*MCl 2)(μ− meso -dpmppm−κ3,κ1)]PF 6 (M = Ir (5a), Rh (5b); Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl). Complex 2a also reacted with [Cp*IrCl 2 ] 2 to yield [Pt(η5-Cp*IrCl 2)(μ− meso -dpmppm−κ3,κ1)(XylNC)]PF 6 (6a) together with 5a , and however, 6a would not react with BnNH 2 , just releasing XylNC to result in 5a. Attachment of the metal fragment of {Cp*IrCl 2 } to the uncoordinated phosphine caused a crucial conformational change of the six-membered chelate ring from a stable chair conformation to a twist-boat structure, which concomitantly reduced reactivity of the isocyanide ligand toward nucleophilic attack of the amine by steric hindrance of meso -dpmppm pincer ligand. These results could be recognized as on/off switching of the asymmetric {PtII(meso -dpmppm−κ3)} pincer complex. Graphical abstract N -Acyclic carbene complexes were synthesized from Pt(II) isocyanides with meso -Ph 2 PCH 2 P(Ph)CH 2 P(Ph)CH 2 PPh 2 which acts as an asymmetric pincer ligand and shows on/off switching induced by ligation of a {Cp*IrCl 2 } unit to its uncoordinate phosphine unit. Image 1 Highlights • The tetraphosphine meso -dpmppm nests a Pt center as an asymmetric pincer ligand. • N -Acyclic carbene PtII complexes were synthesized on the PPP pincer framework. • The asymmetric pincer complex showed on/off switching via ligation of a Ir unit. [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]

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]

From a reaction of [Pt 3 (μ-dpmp) 2 (XylNC) 2 ](PF 6 ) 2 ( 1a ) with NaBH 4 and [Pt(dba) 2 ] in N,N -dimethyl formamide (DMF), a trihydride hexaplatinum complex, [Pt 6 (μ-H)(H) 2 (μ-dpmp) 4 ]BH 4 ·DMF ( 4* ·DMF), was isolated as dark green crystals in 47% yield, and was characterized by IR, UV–vis, 1 H and 31 P{ 1 H} NMR, and ESI mass spectral analyses, X-ray crystallography, and DFT calculations. Complex 4* is stable in DMF and DMSO solutions, and contains two terminal and one bridging hydrides observed at −5.92 ppm ( 1 J PtH = 980 Hz) and −4.47 ppm ( 1 J PtH = 591 Hz) in the 1 H NMR spectrum (DMSO- d 6 ). The X-ray diffraction analysis revealed the linear hexaplatinum structure supported by four dpmp ligands, wherein two {Pt 3 (H)(μ-dpmp) 2 } + units are connected by the bridging hydride resulting in a long Pt⋯Pt separation (3.3075(6) Å) between the central two Pt atoms. Other Pt Pt distances range from 2.7243(7) to 2.7499(6) Å, indicating the presence of Pt Pt bonds within the {Pt 3 (μ-dpmp) 2 } units. On the basis of the crystal structure, the hydride positions were optimized by DFT calculations to show a bent bridging hydride (av. Pt H = 1.65 Å, Pt H Pt = 160.0°) as well as linear terminal ones (av. Pt H = 1.68 Å, av. Pt Pt H = 179.4°). The present study provides useful information in expanding molecular metallic chains by utilizing {H Pt 3 H Pt 3 H} + building blocks. [ABSTRACT FROM AUTHOR]

Linear triplatinum complexes with 48e−, [Pt3(μ-tdpmp)2(RNC)2](PF6)2 (R = 2,6-xylyl (3), tBu (4)), were synthesized by using a branched tetraphosphine, tris(diphenylphosphinomethyl)phosphine (tdpmp), and characterized by crystallographic and spectroscopic analyses to show their novel dynamic behaviour in the solution state, in which the linear Pt3 unit was stabilized by two spinning tetraphosphine ligands. [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]

Reactions of [Cp*MCl 2 ] 2 with meso - or rac -dpmppm in the presence of NH 4 PF 6 afforded mixtures of stereoisomers formulated as [(Cp*MCl) 2 ( meso - or rac -dpmppm)](PF 6 ) 2 , from which the major isomers, rac -M 2 -[(Cp*MCl) 2 ( meso -dpmppm)](PF 6 ) 2 (M = Rh ( 1a ), Ir ( 1b )) and rac -M 2 -[(Cp*MCl) 2 ( rac -dpmppm)](PF 6 ) 2 (M = Rh ( 2a ), Ir ( 2b )), were isolated and characterized by IR, UV–vis, ESI mass, and 1 H and 31 P{ 1 H} NMR spectroscopy and X-ray crystallography, where dpmppm is bis{[(diphenylphosphinomethyl)phenyl]phosphino}methane and Cp* is η 5 -pentamethylcyclopentadienyl. The isomeric tetraphosphine incorporates two {Cp*MCl} fragments with four-membered chelation through a pair of outer and inner phosphine units, and fixes them ca. 6.9 Å apart from each other. The configurations around the metal centers in 2 were determined to avoid repulsive interaction between the phenyl group on the inner P atom and the M-bound chloride anion, while those in 1 would be determined by minimizing not only the Ph/Cl repulsion but also repulsion between the two metal fragments. In the dichloromethane solutions, the major isomers 1 and 2 were not converted to any other minor isomers even at high temperature, but in dmf and dmso, only 1a was readily transformed into the minor isomer, meso -M 2 -[(Cp*RhCl) 2 ( meso -dpmppm)](PF 6 ) 2 . Cyclic voltammograms of 1a,b and 2a,b demonstrated two irreversible 2e − reduction waves corresponding to M III M III → M I M III → M I M I , in which the mixed-valence states with meso -dpmppm could be stabilized to a larger extent than with rac -dpmppm. Complex 1a heated in acetonitrile with AgOTf/NH 4 OTf afforded a Rh 2 Ag 2 mixed-metal complex, [(Cp*Rh(CH 3 CN)) 2 Ag 2 (OTf) 2 ( meso -dpmppm) 2 ](OTf) 4 ( 5 ). [ABSTRACT FROM AUTHOR]

[Display omitted] • Linear P 3 , P 4 , and P 6 phosphines with short bite distances and their derivatives. • Finely synthesized homo- and hetero tri- and tetranuclear metal assemblies. • Linearly ordered Pt 6 , Pt 2 Pd 2 Pt 2 , Ag 6 , Au 6 , and Pd 8 chains with polyphosphines. • Strongly luminous coinage metal clusters with multidentate phosphine ligands. • Copper hydride clusters supported by multidentate phosphine ligands. Structurally constrained multinuclear metal assemblies are fascinating building blocks for atomically precise nano-structured molecular devices with a variety of functions from electronic, magnetic, photophysical, and catalytic properties arising from cooperative effects of proximate metal centers. Finely tuned structures and electronic states of metal assemblies are in debt to design of multidentate guiding and supporting ligands, and aiming to develop low valent metal assemblies as molecular miniatures of metallic materials, those with a pair of soft donors connected by a single atom, namely, bearing short bite units, are highly desired. In this regard, this review surveys the studies over a couple of decades on multinuclear metal complexes constrained by linear and branched tri-, tetra-, and polydentate phosphine ligands with short bite distances between the two donor atoms possessing P 3 , P 4 , and P 6 donor sets. Those with mixed donor phosphines having PCP, PNP, PAsP, PNNP, and N(P 3) donor sets, are also explained because the hetero soft donors of carbene, imino-nitrogen, and arsine enable fine stepwise syntheses of heterometal assemblies through metallomacrocyclic and metallocage precursors. Multinuclear complexes supported by non-phosphino multidentate ligands and by mono- and diphosphines are not included. This contribution focuses not only on 1D metal chains but on other 2D and 3D topological arrangements, and in particular, highlights the recently developed Pt and Pd based metal strings organized by linear tri- and tetraphosphine ligands, photo- and electroluminescent coinage metal assemblies in linear, ring, planar, and polyhedral metal arrangements, and copper hydride multinuclear complexes showing attractive hydride reactivity. These compounds of subnano- to nano-scaled building blocks will provide useful platforms to develop further assembled nano-molecular devices with structurally and atomically controlled synthetic strategies. [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]

A linearly ordered tetraphosphine containing electron-withdrawing substituent groups on the outer phosphorus atoms, meso-bis[{di(3,5-difluorophenyl)phosphinomethyl}phenylphosphino]methane (dpmppmF2), was prepared and reacted with [Pd2(RNC)6](PF6)2 and Pd(dba)2 to afford tetranuclear palladium complexes, [Pd4(μ-dpmppmF2)2(RNC)3](PF6)2 (R = 2,6-xylyl (Xyl) (1), 2,4,6-mesityl (2), 2,6-diisopropylphenyl (3) and tert-butyl (4)), which involve an asymmetric {(RNC)Pd4(CNR)2}2+ core supported by two dpmppmF2 ligands in anti-arrangement. Each terminal of the Pd4 chain was capped by terminal isocyanide and a semi-bridging RNC is introduced into one terminal Pd site. Mechanistic investigation suggested that the dipalladium(i) complex, [Pd2(μ-dpmppmF2)2(RNC)2](PF6)2 (R = Xyl (6)), was a key intermediate to trap Pd0 species by the uncoordinated outer phosphine pendants with electron-withdrawing groups. Variable-temperature UV-vis and 31P{1H}, 1H NMR spectroscopic studies demonstrated that the tetrapalladium complexes are quite fluxional in the solution state at high temperature (＞20 °C) relating to a symmetric structure of [Pd4(μ-dpmppmF2)2(RNC)2](PF6)2, and the asymmetric solid state structures are retained even in the solution at low temperature (＜−60 °C). Theoretical calculations with DFT methods on the asymmetric (R = Xyl (1)) and symmetric (R = Xyl (1′)) structures suggested that contribution of Pd0→PdI–Pd0–PdI with 60 cluster valence electrons (CVEs) would be dominant in 1, while the symmetric structure of 1′ can be recognized as PdI–Pd0–Pd0–PdI with 58 CVEs. The new tetraphosphine dpmppmF2 was proven very effective in organizing dynamically flexible tetrapalladium chains. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of [RhCl(cod)]2 with 2,7-bis(diphenylphosphino)-1,8-naphthyridine (dpnapy) and 2,6-xylyl isocyanide (XylNC) in the presence of NH4PF6 afforded the dirhodium(I) complex, [Rh2(μ-dpnapy)2(XylNC)4](PF6)2 (5), and similar procedures using [MCl2(cod)] (M=Pt, Pd) resulted in the formation of [Pt2(μ-dpnapy)2(XylNC)4](PF6)4 (6) and [Pd2Cl2(μ-dpnapy)2(XylNC)2](PF6)2 (7). Complexes 5–7 were characterized by elemental analysis, IR, UV–Vis, 1H and 31P{1H} NMR, and ESI mass spectroscopic techniques, to involve a small and rigid d 8 {M2(μ-dpnapy)2} metallomacrocycle. Complex 5 readily incorporated a silver(I) ion into the macrocycle to afford [Rh2Ag(μ-dpnapy)2(XylNC)4](PF6)3 (8) which was characterized by X-ray crystallography. The Ag(I) ion is trapped by two trans N atoms of dpnapy ligands, resulting in an asymmetric Rh–Ag⋯Rh structure, determined as a disordered model in the crystal structure, and however, in a CH2Cl2 solution, a dynamic interconversion of the two Ag-trapped sites was observed with low-temperature NMR studies, which was further supported by DFT molecular orbital calculations. When an acetonitrile solution of complex 5 was treated over a droplet of mercury(0), the polymeric compound formulated as {[Rh(μ-dpnapy)(XylNC)2](PF6)} n (9) was isolated as yellow single crystals, which were revealed by X-ray crystallography to consist of C 6 helical rods along c axis with a pitch of 33.5Å (rise of unit=5.6Å) and a diameter of 20.64Å. [Copyright &y& Elsevier]

Reactions of CuX2-nH2O with the biscarboxylate ligand XDK (H2XDK = m-xylenediamine bis(Kemp's triacid imide)) in the presence of N-donor auxiliary ligands yielded a series of dicopper(ll) complexes, [Cu2(u-OH)(XDK)(L)2]X (L = N,N,N',N'-tetramethylethylenediamine (tetmen), X = NO3 (1a), Cl (1b); L = N,N,N'-trimethylethylenediamine (tmen), X = NO3 (2a), Cl (2b); L = 2,2'-bipyridine (bpy), X = NO3 (3); L = 1,10-phenanthroline (phen), X = NO3 (4); L = 4,4'-dimethyl-2,2'-bipyridine (Me2bpy), X = NO3 (5); L = 4-methyl-1,10-phenanthroline (Mephen), X = NO3 (6)). Complexes 1-6 were characterized by X-ray crystallography (Cu···Cu = 3.1624(6)-3.2910(4) Å), and the electrochemical and magnetic properties were also examined. Complexes 3 and 4 readily reacted with diphenyl phosphoric acid (HDPP) or bis(4-nitrophenyl) phosphoric acid (HBNPP) to give [Cu2(μ-phosphate)(XDK)(L)2]NO3 (L = bpy, phosphate = DPP (11); L = phen, phosphate = DPP (12), BNPP (13)), where the phsophate diester bridges the two copper ions in a μi ,3-O,O' bidentate fashion (Cu···Cu = 4.268(3)-4.315(i) Å). Complexes 4 and 6 with phen and Mephen have proven to be good precursors to accommodate a series of sugar monophosphate esters (Sugar-P) onto the biscarboxylate-bridged dicopper centers, yielding [Cu2(μ-Sugar-P)(XDK)(L)2] (Sugar-P = α-D-Glc-1-P (23a and b), D-Glc-6-P (24a and b), D-Man-6-P (25a), D-Fru-6-P (26a and b); L = phen (a), Mephen (b)) and [Cu2(μ-Gly-n-P)(XDK)(Mephen)2] (Gly-n-P = glycerol n-phosphate; n = 2 (21), 3 (22)), where Glc, Man, and Fru are glucose, mannose, and fructose, respectively. The structure of [Cu2(μ-MNPP)(XDK)(phen)2(CH3OH)] (20) was characterized as a reference compound (H2MNPP = 4-nitrophenyl phosphoric acid). Complexes 4 and 6 also reacted with D-fructose 1 ,6-bisphosphate (D-Fru-1,6-P2) to afford the tetranuclear copper(ll) complexes formulated as [Cu4(μ-D-Fru-1,6-P2)(XDK)2(L)4] (L = phen (27a), Mephen (27b)). The detailed structure of 27a was determined by X-ray crystallography to involve two different tetranuclear complexes with α- and β-anomers of D-Fru-1,6-P2, [Cu4(μ-α-D-Fru-1,6-P2)(XDK)2(phen)4] and [Cu4(μ-β-D-Fru-1,6-P2)(XDK)2(phen)4], in which the D-Fru-1,6-P2 tetravalent anion bridges the two [Cu2(XDK)(phen)2]2+ units through the C1 and C6 phosphate groups in a μ-1,3-O,O' bidentate fashion (Cu···Cu = 4.042(2)-4.100(2) Å). Notably, the structure with α-D-Fru-1,6-P2 demonstrated the presence of a strong hydrogen bond between the C2 hydroxyl group and the C1 phosphate oxygen atom, which may support the previously proposed catalytic mechanism in the active site of fructose-i 6- bisphosphatase. [ABSTRACT FROM AUTHOR]

A new sugar-derived Schiff's base ligand N-(3-tert-butyl-2-hydroxybenzylidene)-4,6-O-ethylidene-β-D-glucopyranosylamine (H3L¹) has been developed which afforded the coordinatively labile, alcoholophilic trinuclear Cu(II) complex [Cu3(L¹)2(CH3OH)(H2O)] (1). Complex 1 has been further used in the synthesis of a series of alcohol-bound complexes with a common formula of [Cu3(U)2(ROH)2] (R = Me (2), Et (3), npr (4), nBU (5), nOct (6)). X-ray structural analyses of complexes 2–6 revealed the collinearity of trinuclear copper(II) centers with Cu-Cu-Cu angles in the range of 166–172°. The terminal and central coppers are bound with NO3 and O4 atoms, respectively, and exhibit square-planar geometry. The trinuclear structures of 2–6 can be viewed as the two {Cu(U)}- fragments capture a copper(II) ion in the central position, which is further stabilized by a hydrogen-bonding interaction between the alcohol ligands and the sugar C-3 alkoxo group. Complex 2 exhibits a strong antiferromagnetic interaction between the Cu(II) ions (J = -238 cm-1). Diffusion of methanol into a solution of complex 1 in a chloroform/THF mixed solvent afforded the linear trinuclear complex [Cu3(L¹)2(CH3OH)2(THF)2] (7). The basic structure of 7 is identical to complex 2; however, THF binding about the terminal coppers (Cu-OTHF = 2.394(7) and 2.466(7) Å) has introduced the square-pyramidal geometry, indicating that the planar trinuclear complexes 2–6 are coordinatively unsaturated and the terminal metal sites are responsible for further ligations. In the venture of proton-transfer reactions, a successful proton transfer onto the saccharide C-3 alkoxo group has been achieved using 4,6-O-ethylidene-D-glucopyranose, resulting in the self-assembled tetranuclear complex, [Cu4(HL¹)4] (8), consisting of the mononuclear Cu(II) chiral building blocks, {Cu(HL¹)}. [ABSTRACT FROM AUTHOR]

Examines the interaction between zinc(II) and copper(II) homo and heterotrimetallic complexes involving dextro-glucopyranosyl and biscarboxylate ligands. Characterization of complexes by analytical and spectroscopic measurement; Application of X-ray metallography.

Investigates the structure of trimanganese complexes with N-glycoside ligands derived from seven-coordinate manganese(II) complexes. Identification of complex cation in mononuclear manganese(II)-sugar complexes; Determination of the analogous trinuclear complexes; Characterization of the terminal and central manganese(II) atoms.

Cover Feature: Octapalladium Strings Trap C60 and C70 Fullerenes Affording Metal-Chain-Wired Bucky Balls (Chem. Eur. J. 51/2021) Keywords: chiral fullerenes; extended metal atom chains; metallofullerenes; palladium strings; tetraphosphine EN chiral fullerenes extended metal atom chains metallofullerenes palladium strings tetraphosphine 12918 12918 1 09/13/21 20210909 NES 210909 B The cover picture shows b octapalladium metal strings catching a soccer ball of C SB 60 sb or C SB 70 sb fullerene in the central Pd-Pd junction to give metal-chain-wired bucky balls. Chiral fullerenes, extended metal atom chains, metallofullerenes, palladium strings, tetraphosphine. [Extracted from the article]

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]

• Tetraphosphine meso -dpmppm supports bent tetranuclear Rh 4 chains. • The Rh 4 core reacted with H 2 (1 atm) to afford Rh 4 H 3 hydride complexes. • The linear Rh 4 H 3 structure was determined by XRD and DFT calculations. A linear tetraphosphine, meso -Ph 2 PCH 2 P(Ph)CH 2 P(Ph)CH 2 PPh 2 (meso -dpmppm), was found to support a series of bent tetranuclear rhodium(I) arrays of [Rh 4 (μ−Cl)Cl 2 (CO) 4 (meso -dpmppm) 2 ]Cl (1), [Rh 4 (μ−Cl) 2 (meso -dpmppm) 2 ]X 2 (X = PF 6 (2a), BF 4 (2b), TfO (2c), BPh 4 (2d)), and [Rh 4 (μ−Cl)(CH 3 CN) 2 (CO) 4 (meso -dpmppm) 2 ](TfO) 3 (3) which are regarded as tetranuclear extended Vaska-type RhI complexes. Two meso -dpmppm ligands with mutual syn -arrangement established a flexible bending chains of {Rh 4 (meso -dpmppm) 2 }4+ which accommodated a variety of ligand sets of {(μ−Cl)Cl 2 (CO) 4 }3‒, {(μ−Cl) 2 (CO) 4 }2‒, and {(μ−Cl)(CH 3 CN) 2 (CO) 4 }‒ with Rh–Rh–Rh angles of 142.18(1)–161.54(1)°. The tetranuclear rhodium(I) core of 2 was interestingly reactive toward H 2 (1 atm) under mild conditions at room temperature to afford {Rh 4 H 3 }3+ hydride complexes with linear RhI∙∙∙RhII–RhII∙∙∙RhI array, [Rh 4 (μ−Cl) 2 (μ−H) 3 (μ−CO)(CO) 2 (meso -dpmppm) 2 ]X (X = PF 6 (4a), BF 4 (4b), TfO (4c)), where the positions of three hydride ligands were estimated with 1H, 1H{31P}, and 31P{1H} NMR spectra, a single crystal X-ray diffraction analysis, and DFT calculations. The linearly ordered {Rh 4 H 3 }3+ species that store four electrons from dihydrogen molecules is the first example of linear Rh hydride chains and would be useful platform for exploring cooperative reactions promoted by constrained multimetallic centers. [Display omitted] [ABSTRACT FROM AUTHOR]

Focuses on the peroxobridged dinuclear cobalt(III) complexes containing N-glycoside ligands from tris(2-aminoethyl)amine and d-glucose or maltose. Use of elemental analysis, UV-vis absorption, circular dichroism, 1H and 13C NMR spectroscopic techniques, X-ray absorption and crystalographic analyses; Deviation of hydrogen bonding and sugar moieties.

Studies the incorporation of monovalent group 11 metal ions into the diplatinum core leading to heterometallic complexes. Structures of metal centers; Description of multidentate phosphines as the supporting ligand to the heteronuclear complexes; Usefulness of the reactions in the synthesis of heteronuclear complexes.

Describes the synthesis and characterization of calcium-bridged dimagnesium(II) complexes. Use of the dinucleating ligand XDK, where H2XDK is m-xylyenediamine bis(Kemp's triacid imide); Reaction of the complexes with bis(4-nitrophenyl) hydrogen phosphate; Phosphate ester exchange rate of free and bound diphenyl phosphate in methanol solution.

Examines the synthesis, structures, and spectroscopic, magnetic, and electrochemical properties of diruthenium complexes and hydroxypropanetetraacetic acid. Materials, measurements, and preparations; X-ray crystallographic analysis; Atomic positional and thermal parameters for non-hydrogen atoms; Selected bond distances and angles.

Describes the assembly of aldoses on nickel(II) ion by utilizing the N-glycosidic bond formation with tren. Nickel(II) bis(sugar) complexes; Crystal structures of complexes; Nickel(II) mono(sugar) complexes; Nickel(II) tri(sugar) complexes; Preparation and reactions.

Discusses the metal-to-metal bonding of platinum and palladium complexes through phosphine ligands. Bond distances and angles; Characteristics and structures; Production of assymetrical A-frame complexes; Chemical reactions involved.

Studies zinc-containing carboxylate-bridged heterodimetallic complexes and their reactions with phosphodiester ligands. Crystallographic data; Preparation of materials; Structure solution and refinement; Assignments of metals; Structural parameters.

Investigates the synthesis of dinuclear manganese(II) complexes by utilizing the dinucleating, dicarboxylate ligand XDK, H2XDK = meta-xylenediamine bis(Kemp's triacid imide) as a platform. Oxidation of the compounds by excess tert-butyl hydroperoxide in methanol; Structural characterization by X-ray crystallography.

Presents a synthetic route to carboxylate-bridged dizinc complexes established by utilizing XDK, where H2XDK is meta-xylenediamine bis(Kemp's triacid imide). Formation of mononuclear and dinuclear zinc complexes; Product of the introduction of phosphate esters into the dizinc core.

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 synthesis and characterization of copper(II) complexes containing N-glycoside ligands and their use in catalytic reactions promoted by transition metal complexes. Reaction of copper(II) salts with aldoses and ethylenediamine; Description of structures of complexes; Catalysis of epoxidation of olefins; Conversion of (E)-cinnamyl acetate into its epoxide.

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.

• Tetraphosphine rac -dpmppm supports tetranuclear Ag 4 and PtAg 2 Pt zigzag arrays. • The detailed tetranuclear structures were characterized by X-ray analyses. • PtAg 2 Pt acetylide complex emits intense photoluminescence at 534 nm. Reaction of AgOTf with a tetraphosphine, rac -bis[(diphenylphosphinomethyl) phenylphosphino]methane (rac -dpmppm), afforded [Ag 4 (rac -dpmppm) 2 (TfO) 4 (3) which consists of zigzag-arrayed tetranuclear silver(I) ions supported by syn -arrangement of two enantiomeric (RR / SS) dpmppm ligands. Complex 3 readily reacted with XylNC (Xyl = 2,6-dimethylphenyl) to give [Ag 4 (rac -dpmppm) 2 (XylNC) 2 (TfO) 4 (4), where two terminal isocyanides attach to the outer Ag sites. Complex 3 has been shown a good precursor for Pt-Ag-Ag-Pt mixed metal array as incubation of 3 with trans -[Pt(C CPh) 2 (PPh 3) 2 yielded [Ag 2 Pt 2 (C CPh) 4 (rac -dpmppm) 2 (TfO) 2 (5). Two trans -Pt(C CPh) 2 units are incorporated into the terminal positions in a site-selective fashion and the Pt-Ag-Ag-Pt tetranuclear core also adopts a zigzag array supported by syn -arrangement of two rac -dpmppm ligands. The d8 and d10 closed-shell mixed metal centers of 5 exhibited an intense photoluminescence at 534 nm, mainly from an unsymmetric triplet state generated by charge transfer transitions from ligand (acetylide π) to metal centers (Ag 2 and PtAg s/p σ), 3LMCT, and to ligands (acetylide π* and dpmppm), 3LLCT. The present results provide fundamental and useful information to construct multinuclear closed-shell metal alignments by utilizing polyphosphine ligands. [ABSTRACT FROM AUTHOR]

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]

The novel tetranuclear copper(II) complexes with α-D-glucose-1-phosphates, [Cu4(μ-OH)(α-D-Glc-1P)2(L)4(H2O)2](NO3)3 (L = bpy (1), phen (2)), were prepared and characterized by X-ray crystallography. Complex 1 was further transformed into the ATP stabilized tetracopper(II) complex of [Cu4(ATP)2(bpy)4] (4), where ATP is adenosine 5′-triphosphate. [ABSTRACT FROM AUTHOR]

Highlights from the article: Cover Feature: Alloyed Tetranuclear Metal Chains of Pd4-nPtn (n=0-3) Scaffolded by a New Linear Tetraphosphine Containing a PNP Bridge (Chem. Eur. J. 35/2019) Keywords: alloyed metal chain; EMAC; PdPt mixed metal complex; PNP bridged tetraphosphine; tetranuclear complexes Alloyed metal chain, EMAC, PdPt mixed metal complex, PNP bridged tetraphosphine, tetranuclear complexes.

Chiral self‐recognition between stereogenic tetrapalladium units, [Pd4(rac‐dpmppm)2]2+ ((RR)2, (SS)2) and [Pd4(meso‐dpmppm)2]2+ ((RS)2) {dpmppm=[(Ph2PCH2)PhP]2CH2}, afforded Pd8 chains supported by homochiral dpmppm ligands, [Pd8(rac‐dpmppm)4]4+ ((RR)4, (SS)4) and [Pd8(meso‐dpmppm)4]4+ ((RS)2(SR)2, (SR)2(RS)2). Among ten possible stereoisomers, only four Pd8 chains were thermodynamically self‐aligned; the C2 chiral structure of the chain is determined by the configuration of the P centers inside. More information can be found in the Communication by T. Tanase et al. on page 524 ff. [ABSTRACT FROM AUTHOR]

Focuses on the synthesis and structural characterization of three novel carboxylate-bridged dimagnesium(II) complexes. Complexes as useful bioorganic models of the active sites in enzymes used to hydrolyze phosphate esters; Complexes as models for fitting electron density in protein crystal structures; Differences in phosphate exchange rates for dimagnesium and dizinc complexes.

Reports on a new general route to heterodimetallic complexes bridged by the dinucleating carboxylate ligand XDK, where H2XDK is m-xylenediamine bis(Kemp's triacid imide). Formation of a mononuclear Zn(II) derivative; Possible replacement of the ligands of [ZnM(XDK)(acac)2(CH3OH)2] by phosphate esters.

Reports on the synthesis of a novel seven-coordinated cage-cobalt complexes containing N-glycosides from mannose-type aldoses (D-mannose) of L-rhamnose (=6-deoxyl-L-mannose) and tris (2-aminoethyl)-amine (tren). Interactions between sugars and tetrahedral oxoanions; Synthesis of nickel(II) and cobalt (III) complexes.