Full Protection of Intensely Luminescent Gold(I)–Silver(I) Cluster by Phosphine Ligands and Inorganic Anions

An intensely luminescent gold(I)–silver(I) cluster [(C)(AuPPhpy₂)₆Ag₆(CF₃CO₂)₃](BF₄)₅ (PPhpy₂=bis(2-pyridyl)phenylphosphine) ( 3 ) is synthesized by the reaction of [(C)(AuPPhpy₂)₆Ag₄](BF₄)₆ with AgCF₃CO₂. All eight faces of the octahedral C@Au₆ core in 3 are capped, that is, six faces are capped by silver ions and two by tetrafluoroborates. Cluster 3 is intensely luminescent in solution with a quantum yield of 92 %. Ligation of CF₃CO₂⁻ ions is vital for the construction and emission properties of 3 , as confirmed by DFT calculations. BF₄⁻ ions are involved in the protecting sphere of the metal core, as evidenced by ¹⁹F NMR data. The participation of phosphines, CF₃CO₂⁻, and BF₄⁻ ions in the protection of the emissive core and the enhancement of the rigidity of the cluster result in the high emission efficiency. This is the first example of organic ligands and inorganic anions forming a rigid protecting sphere for luminescent coinage-metal clusters.     

Effect of the Composition of Ethanol–DMSO Solvents on the Stability of Silver(I) Complexes with 18-Crown-6

The effect of composition of ethanol–dimethyl sulfoxide (EtOH–DMSO) solvents (χ_DMSO = 0.0–1.0 mole fractions) on the stability of silver(I) complexes with 18-crown-6 ether (18C6) has been studied potentiometrically at 298.15 K. The increasing of DMSO concentrations in mixed solvents are shown to considerably reduce the stability of 18C6 complexes with silver(I) ion ([Ag18C6]⁺). A change in the solvation state of the central ion is suggested to be the key factor in shifting complexing equilibrium.     

Positive Cooperativity Induced by Interstrand Interactions in Silver(I) Complexes with α,α′-Diimine Ligands

The allosteric positive cooperativity accompanying the formation of compact [Cu^I(α,α′-diimine)₂]⁺ building blocks contributed to the historically efficient synthesis of metal-containing catenates and knotted assemblies. However, its limited magnitude can easily be overcome by the negative chelate cooperativity that controls the overall formation of related polymetallic multistranded helicates and grids. Despite the more abundant use of analogous dioxygen-resistant [Ag^I(α,α′-diimine)₂]⁺ units in modern entangled metallo-supramolecular assemblies, a related thermodynamic justification was absent. Solid-state structural characterizations show the successive formation of [Ag^I(α,α′-diimine)(CH₃CN)][X] and [Ag^I(α,α′-diimine)₂][X] upon the stepwise reactions of α,α′-diimine=2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) derivatives with AgX (X=BF₄⁻, ClO₄⁻, PF₆⁻). In room-temperature, 5–10 mM acetonitrile solutions, these cationic complexes exist as mixtures in fast exchange on the NMR timescale. Spectrophotometric titrations using the unsubstituted bpy and phen ligands point to the statistical (=non-cooperative) binding of two successive bidentate ligands around Ag^I, a mechanism probably driven by the formation of hydrophobic belts, that overcomes the unfavorable decrease in the positive charge borne by the metallic cation. Surprisingly, the addition of methyl groups adjacent to the nitrogen donors (6,6′ positions in dmbpy; 2,9 positions in dmphen) induces positive cooperativity for the formation of [Ag(dmbpy)₂]⁺ and [Ag(dmphen)₂]⁺, a trend assigned to additional stabilizing interligand interactions. Adding rigid and polarizable phenyl side arms in [Ag(Brdmbpy)₂]⁺ further reinforces the positively cooperative process, while limiting the overall decrease in metal–ligand affinity.     

Secondary Interactions or Ligand Scrambling? Subtle Steric Effects Govern the Iridium(I) Coordination Chemistry of Phosphoramidite Ligands

The like and unlike isomers of phosphoramidite (P*) ligands are found to react differently with iridium(I), which is a key to explaining the apparently inconsistent results obtained by us and other research groups in a variety of catalytic reactions. Thus, the unlike diastereoisomer (aR,S,S)‐[IrCl(cod)( 1 a )] ( 2 a ; cod=1,5‐cyclooctadiene, 1 a =(aR,S,S)‐(1,1′‐binaphthalene)‐2,2′‐diyl bis(1‐phenylethyl)phosphoramidite) forms, upon chloride abstraction, the monosubstituted complex (aR,S,S)‐[Ir(cod)(1,2‐η‐ 1 a ,κP)]⁺ ( 3 a ), which contains a chelating P* ligand that features an η² interaction between a dangling phenyl group and iridium. Under analogous conditions, the like analogue (aR,R,R)‐ 1 a′ gives the disubstituted species (aR,R,R)‐[Ir(cod)( 1 a′ ,κP)₂]⁺ ( 4 a′ ) with monodentate P* ligands. The structure of 3 a was assessed by a combination of X‐ray and NMR spectroscopic studies, which indicate that it is the configuration of the binaphthol moiety (and not that of the dangling benzyl N groups) that determines the configuration of the complex. The effect of the relative configuration of the P* ligand on its iridium(I) coordination chemistry is discussed in the context of our preliminary catalytic results and of apparently random results obtained by other groups in the iridium(I)‐catalyzed asymmetric allylic alkylation of allylic acetates and in rhodium(I)‐catalyzed asymmetric cycloaddition reactions. Further studies with the unlike ligand (aS,R,R)‐(1,1′‐binaphthalene)‐2,2′‐diyl bis{[1‐(1‐naphthalene‐1‐yl)ethyl]phosphoramidite} ( 1 b ) showed a yet different coordination mode, that is, the η⁴‐arene–metal interaction in (aS,R,R)‐[Ir(cod)(1,2,3,4‐η‐ 1 b ,κP)]⁺ ( 3 b ).     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C≡CPh)]_n with a NP_3 Ligand

1 INTRODUCTION Great attention has currently been paid to com-pounds formed by the reaction between phosphineand metal alkynyl building blocks[1]. The ligand NP3contains one tertiary nitrogen atom as well as threephosphorous atoms and bonds to the metal ions as atetradentate ligand, affording tetrahedral[2] or triangle-bipyrimidal geometry[3, . In other coordination ca- 4]ses, one[5, , two[7], three P donors[8, 6] …     

Cd(II) and Cd(II)–Eu(III) Complexes with Pentafluorobenzoic Acid Anions and N-Donor Ligands: Synthesis and Structures

Russian Journal of Coordination Chemistry - The reactions of cadmium(II) and europium(III) pentafluorobenzoates ([Cd(Pfbz) $$left( {{{{text{H}}}_{{text{2}}}}{text{O}}} right)_{{text{4}}}^{ +...     

Silver(Ⅰ) Complexes with Mixed Diphosphine Ligands:Syntheses,Characterization and Spectroscopic Properties

Two novel silver(I) complexes [Ag(DPEphos)(dppe)]Cl O4(1) and [Ag(DPEphos)-(dppe)]SCN(2)(DPEphos = bis[2-(diphenylphosphino)phenyl]ether, dppe = bis(diphenylphosphino)ethane) are synthesized and characterized by IR, 1H/31 P NMR spectroscopy and fluorescence spectra. Complex 1 crystallizes in monoclinic, space group P21/c with a = 14.8821(12), b = 12.6620(11), c = 36.025(3) ?, β = 112.633(2)°, V = 6265.7(9) ?3, C62H52 Cl O5P4Ag, Mr = 1144.24, Z = 4, Dc = 1.213 g/cm3, F(000) = 2352, μ = 0.510 mm-1, the final R = 0.0616 and w R = 0.1192 for 4003 observed reflections(I 2σ(I)). Complex 2 crystallizes in monoclinic, space group P21/c with a = 14.9021(13), b = 12.6100(11), c = 35.920(3) ?, β = 112.852(2)°, V = 6220.2(9) ?3, C63H52NOP4 SAg, Mr = 1102.87, Z = 4, Dc = 1.178 g/cm3, F(000) = 2272, μ = 0.498 mm-1, the final R = 0.0912 and w R = 0.1706 for 3287 observed reflections(I 2σ(I)). In mono-nuclear complexes 1 and 2, the Ag(I) atom is chelated by DPEphos and dppe ligand. In the 31 P NMR spectra, there are splitting signals(doublets or triplets) which can be attributed to the coupling of the 107,109Ag–31P(from DPEphos or dppe ligand). All the emission peaks of these complexes are attributed to ligand-centered(π-π*) transitions.     

Silver(I) Oxide on Silver–Zinc Alloys: Anodic Formation and Properties

Russian Journal of Electrochemistry - Anodic formation in deoxygenated 0.1 М KOH solution of Ag(I) oxide on Ag–Zn alloys with zinc atomic fraction from 5 to 30 at % and its properties...     

New σ-alkynylides of Cu(I) and Ag(I)

Polymeric compounds of the type (MCCR)_x (MCu, Ag; R = cyclohexyl, n-hexyl) and M₂(p-(CC)C₆H₄)] _x (MCu, Ag) have been prepared. The preparation media and solvent (liquid ammonia, methanol and methanol/ or methanol-ether/aqueous ammonia) exert an influence over the nature of the alkynyl compound, leading either to the formation of adducts or to the formation of metal alkynylides with identical empirical formulae, but differing in colour, which seems be related to the different extent of molecular association.     

The Impact of Crystal Packing and Aurophilic Interactions on the Luminescence Properties in Polymorphs and Solvate of Aroylacetylide–Gold(I) Complexes

The influence of the chemical substitution, crystal packing, and aurophilic interactions of the gold(I) acetylide complexes of the type (ArCOC≡C)_nAuPEt₃ (n=1,2) on their luminescent properties were examined. All described complexes undergo ligand scrambling in solution, which results in the formation of stable, easily isolated crystals that contain [ArCO(C≡C)_n]₂Au⁻(Et₃P)₂Au⁺ homoleptic species. In particular, we observed that the (benzoylacetylide)gold(I) complex yields three crystal forms with strikingly different luminescence properties. We monitored the conversion pathway for these forms: an orange luminescent form of homoleptic complex upon drying undergoes spontaneous transformation to bright green fluorescent form and finally to the weakly blue emissive one. In addition, we report a rare example of a helical arrangement of Au⋅Au⋅Au chains that are observed for the first time in acetylide gold(I) complexes in the case of heteroleptic (benzoylacetylide)gold(I) complex. This is a very rare case in which crystal structures and ensuing electronic properties of the heteroleptic and Au^I complexes could be directly compared.     

Polynuclear Silver(Ⅰ) Complexes with Phosphorus Ligands and 4,4'-Bipyridine:Synthesis,Structural Characterization and Spectroscopic Properties

Two novel silver(I) complexes {[Ag(OTf)(PPh3)(4,4'-bipy)]}∞(1) and {[Ag2-(OTf)2(dppb)3](CH3CN)4}∞(2)(OTf = trifluoromethanesulfonate, PPh3 = triphenylphophine, 4,4'-bipy = 4,4'-bipyridine, dppb = bis(diphenylphosphino)butane) have been synthesized and characterized by IR, single-crystal X-ray diffraction, fluorescence spectrum and 1H NMR spectroscopy. Complex 1 crystallizes in orthorhombic, space group Pna21 with a = 19.259(2), b = 9.85070(12), c = 16.3827(17) ?, V = 3108.0(5) ?3, C29H23F3N2O3 PSAg, Mr = 675.39, Z = 4, Dc = 1.443 g/cm3, F(000) = 1360, μ = 0.816 mm-1, the final R = 0.0675 and w R = 0.1722 for 3662 observed reflections(I 2σ(I)). Complex 2 crystallizes in triclinic, space group P1 with a = 12.9370(11), b = 13.5261(13), c = 16.4539(15) ?, α = 106.7120(10), β = 97.3830(10), γ = 113.027(2)?, V = 2441.2(4)?3, C94H96F6N4O6P6S2Ag2, Mr = 1957.43, Z = 1, Dc = 1.331 g/cm3, F(000) = 1006, μ = 0.605 mm-1, the final R = 0.0717 and w R = 0.1795 for 5128 observed reflections(I 2σ(I)). Complex 1 is of zigzag chain structure, in which each Ag atom is coordinated by one OTf- anion, two N atoms from two 4,4'-bipy molecules and one P atom from PPh3 ligand. In 2, the central Ag atom is coordinated with one OTf- anion and three P atoms from three dppb ligands, which leads to the formation of a zigzag ring-bridge-ring chain with each ring consisting of two Ag atoms and two dppb ligands.     

Temperature- and pressure-dependent utilising dimensionality cross-over of Silver(I) complex supported by short Ag···Ag Interactions

Two Ag(I)-based complexes, a mononuclear [Ag(PPh₃)₂(2tpCOO)]·EtOH (1) and a tetranuclear [Ag₄(PPh₃)₄(2tpCOO)₄] (2) have been prepared by a small tuning on the molar ratio of the reactants as well as the crystallisation method. A 1-D polymeric structure, [Ag₂(PPh₃)(2tpCOO)₂]_n (3) was obtained while the crystals of 2 were left under high temperature and autogenous pressure. The study suggests that the formation of 1-D polymeric structure is due to the removal along with the intramolecular and intermolecular reorganisation of the coordinated ligands that leads to dimensionality cross-over from 0-D to 1-D. The rearrangement of the ligands in 3 also resulted the metal centres moving closer together, being separated by 2.9626(3) Å in 3, compared to 3.215(8) Å in 2. The photoluminescence properties have been investigated showing that only complexes 2 and 3 exhibit this property at room temperature in solid state that is due to metal-to-ligand charge transfer.     

Computational Bottom-up Design of Ytterbium(Ⅱ) Complex with Pyridyl Amido Ligand

Having been designed via bottom-up strategy based on density functional theory(DFT) calculations, a complex of ytterbium(Ⅱ) with pyridyl amido ligand was successfully synthesized by one-pot reaction in laboratory. DFT calculation shows that pyridyl amido ligands can stabilize the complex via steric and electron effect. This success in integrating computation with synthesis will inspire more explorations in the development of a new complex in lanthanide chemistry.     

Effects of molecular structure and equivalent weight on facilitated transport of alkenes in Ag(I)–PFSI membranes

Fluxes and separation factors are reported for the facilitated transport of a variety of C₆ alkenes and dienes through two Ag(I)-exchanged polyfluorosulfonate ionomer membranes. For acyclic dienes, the largest separation factors are observed between those compounds with the greatest difference in spacing of the double bonds, and those with completely external versus internal double bonds. For cases where the spacing of the double bonds is the same, the compound with at least one terminal double bond exhibited a higher flux. The trends in fluxes for cyclic dienes is quite different; 1,4-cyclohexadiene is transported more slowly than cyclohexene while 1,3-cyclohexadiene is transported almost eight times more rapidly than cyclohexene. Methyl-substituents on the carbons comprising double bonds have minor effects on the transport properties. As anticipated, PFSI materials that contain more ion-exchange sites and absorb greater quantities of water exhibit slightly greater fluxes and separation factors for most alkene separations.     

Synthesis of Aminophosphine Ligands with Binaphthyl Backbones for Silver(I)-catalyzed Enantioselective Allylation of Benzaldehyde

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Syntheses and Crystal Structures of Hg(Ⅱ) and Ag(Ⅰ) Complexes Containing 2-Acetylpyridine-paminobenzoylhydrazone Ligand

The two complexes [HgI_2L](DMF)(1) and [AgL_2](ClO_4)(CH_3CN)(2) were synthesized from the reaction of Schiff base ligand(2-acetylpyridine-p-aminobenzoylhydrazone)(L) with HgI_2 or AgClO_4 respectively. The compounds are characterized by ~1H NMR,FTIR and elemental analysis. The structures of the ligand and two complexes are measured via single-crystal X-ray diffraction. In these two complexes,the structures are both distorted triangular bipyramids with five-coordinated centers.     

Tin(II) Complexes Based on N-Alkyl-Substituted o-Amidophenolate Ligands: Acid–Base and Redox Transformations

Russian Journal of Coordination Chemistry - New stannylene AdAPSn (I) based on 4,6-di-tert-butyl-N-adamantyl-o-aminophenol is synthesized and structurally characterized. Stannylene I in the...     

Influence of Different Organic Carboxylate Anions on the Crystal Structure of Silver(Ⅰ)Coordination Polymers

The reaction of AgNO3 , 4,4′-bipyridine (bpy) and 2,2′-bipyridine-3,3′-dicarboxylic acid (H2bpdc)/2,2′-biquinoline-4,4′-dicarboxylic acid (H2bqdc)/1,3-benzenedicarboxylic acid (H2bdc) gave rise to block-like crystals of [Ag4(bpy)2(bpdc)2]·13H2O(1), [Ag2(bpy)(bqdc)(H2O)]·4.5H2O(2) and [Ag2(bpy)2(H2O)2](bdc)·3H2O(3) by slow evaporation. All the three complexes contain sandwich-like crystal structures, in which anionic sheets built up from different anions (bpdc2- , bqdc2- and bdc2- ) and lattice water molecules via rich hydrogen-bonding interactions are inserted between the cationic silver complex layers, and the abundant Ag···Ag, Ag···N and π-π stacking interactions further strengthen the 3D frameworks. The lattice water molecules are situated among the framework of crystal structure and stabilized by rich hydrogen-bonding interactions, and lattice water molecules may play a role in the orientation of organic anions in the crystal packing. Additionally, the thermal properties of 1, 2 and 3 were also discussed in detail.