Dinuclear Au(I), Au(II) and Au(III) Complexes with (CF2)n Chains: Insights into The Role of Aurophilic Interactions in the Au(I) Oxidation

New dinuclear Au(I), Au(II) and Au(III) complexes containing (CF₂)_n bridging chains were obtained. Metallomacrocycles [Au₂{μ-(CF₂)₄}{μ-diphosphine}] show an uncommon figure-eight structure, the helicity inversion barrier of which is influenced by aurophilic interactions and steric constraints imposed by the diphosphine. Halogenation of LAu(CF₂)₄AuL (L=PPh₃, PMe₃, (dppf)_1/2, (binap)_1/2) gave [Au(II)]₂ species, some of which display unprecedented folded structures with Au−Au bonds. Aurophilic interactions facilitate this oxidation process by preorganizing the starting [Au(I)]₂ complexes and lowering its redox potential. The obtained [Au(II)]₂ complexes undergo thermal or photochemical elimination of R₃PAuX to give Au(III) perfluorinated auracycles. Evidence of a radical mechanism for these decomposition reactions was obtained.     

[Au(C6F5)3(PPh2H)]: A Precursor for the Synthesis of Gold(III) Phosphide Complexes

The covalent radius of Au ^I is about 0.07 Å smaller than that of Ag^I. This was determined from the crystal structures of the isostructural complexes [N(PPh₃)][{Au(C₆F₅)₃(μ-PPh₂)}₂M] (M=Au (structure shown in the picture), Ag). These mixed Au^III–M phosphides were synthesized from [Au(C₆F₅)₃(PPh₂H)], the first gold complex to contain a secondary phosphane.     

Ligand-unsupported Au(I) chains with short Au(I)...Au(I) contacts

A new series of solids with ligand-unsupported Au(I) chains with short Au...Au contacts were synthesized; as Ag compounds with the same structure are known, the new phases now allow unbiased comparison of Ag...Ag and Au...Au metallophilic bonds not supported by bridging ligands, which shows the latter to be consistently shorter by 0.03-0.04 A.     

Highly luminescent octanuclear Au(I)-Cu(I) clusters adopting two structural motifs: the effect of aliphatic alkynyl ligands

Reactions of the homoleptic (AuC(2)R)(n) precursors with stoichiometric amount of diphosphine ligand PPh(2)C(6)H(4)PPh(2) (P^P) and Cu(+) ions lead to an assembly of a new family of bimetallic clusters [Au(6)Cu(2)(C(2)R)(6)(P^P)(2)](2+) (type I; R=9-fluorenolyl (1), diphenylmethanolyl (2), 2,6-dimethyl-4-heptanolyl (3), 1-cyclohexanolyl (4), Cy (5), tBu (6)). In the case of R=1-cyclohexanolyl, a structurally different complex [Au(6)Cu(2)(C(2)C(6)H(11)O)(6)(P^P)(3)](2+) (7, type II) could be obtained by treatment of 4 with one equivalent of the diphosphine, while for R=isopropanolyl only the latter type of cluster [Au(6)Cu(2)(C(2)C(3)H(7)O)(6)(P^P)(3)](2+) (8) was detected. Steric bulkiness of the alkynyl ligands and O···H-O hydrogen bonding are suggested to play an important role in stabilizing the type I and type II cluster structural motif, respectively. All the complexes exhibit intense photoluminescence in solution with emission parameters that depending on the geometrical arrangement of the octanuclear metal core. The clusters 1-4 and 6 show single emission band in a blue region (469-488 nm) with maximum quantum yield of 94% (4), while structurally different 7 and 8 emit yellow-orange (590 nm) with unity quantum efficiency. The theoretical DFT calculations of the electronic structures have been carried out to demonstrate that the metal-centered triplet emission within the heterometallic core plays a key role for the observed phosphorescence.     

砷配合物As(S2CNCy2)2I和As(S2CNC6H12)3的合成和晶体结构

合成了2种砷的氨荒酸配合物As(S₂CNCy₂)₂I (1)和As(S₂CNC₆H₁₂)₃ (2)。通过元素分析和红外光谱对其进行了表征,用X-射线单晶衍射测定了它们的晶体结构。配合物1的晶体属单斜晶系，空间群为P2₁/n，晶胞参数a=1.020 9(4) nm，b=1.468 0(5) nm，c=1.521 8(5) nm，β=92.135(5)°和Z=4。配合物2的晶体属三方晶系，空间群为R3，使用六方坐标，晶胞参数a=1.622 1(4) nm，c=2.119 4(6) nm，并有Z=6。测试结果表明，配合物1为单核结构，中心砷原子为五配位的三角双锥配位构型，此外，在该配合物分子间存在弱的As…S相互作用(As…S 0.351 2(4) nm)，使得该配合物以弱桥连二聚体存在。在配合物2中，3个配体分别以双齿形式与砷原子配位，形成六配位的畸变三棱柱体结构。     

Silver-Free Au(I) Catalysis Enabled by Bifunctional Urea- and Squaramide-Phosphine Ligands via H-Bonding

A library of gold(I) chloride complexes with phosphine ligands incorporating pendant (thio)urea and squaramide H-bond donors was prepared with the aim of promoting chloride abstraction from Au(I) via H-bonding. In the absence of silver additives, complexes bearing squaramides and trifluoromethylated aromatic ureas displayed good catalytic activity in the cyclization of N-propargyl benzamides, as well as in a 1,6-enyne cycloisomerization, a tandem cyclization-indole addition reaction and the hydrohydrazination of phenylacetylene. Kinetic studies and DFT calculations indicate that the energetic span of the reaction is accounted by both the chloride abstraction step, facilitated by the bidentate H-bond donor via an associative mechanism, and the subsequent cyclization step.     

Electronic and resonance Raman spectra of [Au2(CS3)2]2-. Spectroscopic properties of a "short" Au(I)-Au(I) bond

The anion [Au2(CS3)2]2- has an unusually short Au-Au distance (2.80 A) for a binuclear Au(I) complex. We report detailed Raman studies of the nBu4N+ salt of this complex, including FT-Raman of the solid and UV/vis resonance Raman of dimethyl sulfoxide solutions. All five totally symmetric vibrations of the anion have been located and assigned. A band at delta nu = 125 cm-1 is assigned to nu (Au2). The visible-region electronic absorption bands (384 (epsilon 30,680) and 472 nm (epsilon 610 M-1 cm-1)) are attributable to CS3(2-) localized transitions, as confirmed by the dominance of nu sym(C-Sexo) (delta nu = 951 cm-1) in RR spectra measured in this region. An absorption band at 314 nm (22,250 M-1 cm-1) is assigned as the metal-metal 1(d sigma*-->p sigma) transition, largely because nu sym(C-Sexo) is not strongly enhanced in RR involving this band. Observation of the expected strong resonance enhancement of nu (Au2) was precluded as a result of masking by intense solvent Rayleigh scattering in the UV.     

Alkaline Earth Diazapentadienyl Compounds: Structure of [Ba2{(C6H11)NC(Me)CHC(Me)N(C6H11)}3{(SiMe3)2N}]

Three different bonding modes in one molecule! The diazapentadienyl ligands in the title compound 1 adopt η¹,η¹-N,N-chelating plus η⁵-terminal, η¹η¹-N,N chelating plus η⁵-bridging, and novel η¹-N plus η³-1-aza-allyl bonding modes. R=cyclohexyl.     

Synthesis and X-ray structure study on new Au(I) polymer architectures based on multi-sulfur tentacles

Multi-thiolate ligands are used as a scaffold to construct a series of supramolecules, which cover the following entries; [(1,3-S₂-C₆H₄){AuP(C₆H₄-3-CF₃)₃}₂]_n (1), [(1,4-S₂-C₆H₄){AuP(C₆H₄-3-CF₃)₃}₂]_n (2), (1,4-S₂-C₆H₄){AuP(C₆H₅)₂(2-pyridine)}₂ (3), [(1,3,5-S₃-C₆H₃){AuP(C₆H₅)₂(2-pyridine)}₃]_n (4), and [(1,3,5-S₃-C₆H₃){AuP(C₆H₄-3-CF₃)₃}₃]_n (5). The molecular and crystal structures of these new derivatives have been elucidated by single crystal X-ray diffraction. Aurophilic interactions have been demonstrated for 1, 2, 4, and 5 to produce new supramolecular architectures. Nano-channels are formed by aurophilic and π-π interactions for 1, in which benzene molecules are trapped. An 8 (eight)-shaped loop is formed in solid state for 2. Infinite zigzag chains are constructed for 4 and 5.     

Synthese und Strukturen der selenolatoverbrückten Quecksilbercluster [Hg6(SePh)12(PtBu3)2] und (HPtBu3)2[Hg6(SePh)14]

Synthesis and Structures of the Selenolato-Bridged Mercury Clusters [Hg₆(SePh)₁₂(P t Bu₃)₂] and (HP t Bu₃)₂[Hg₆(SePh)₁₄] The reaction of HgCl₂ with PtBu₃ and PhSeSiMe₃ yields [Hg₆(SePh)₁₂(PtBu₃)₂] ( 1 ) and (HPtBu₃)₂[Hg₆(SePh)₁₄] ( 2 ). X-ray structural analysis of the compounds shows them to have similar Hg–Se cages with distorted tetrahedral coordination around mercury. The cages are built up from edge- and vertex-sharing distorted tetrahedra.     

Synthese und Strukturen von [Cu8As3(AsSiMe3)2(dppb)4]+‐[Cu{As2(SiMe3)2}{As4(SiMe3)4}]‐, [Cu8As3(AsSiMe3)2(dppb)4]+‐[Cu{As(SiMe3)2}2]‐ und [Cu10(Sb3)2(SbSiMe3)2(dppm)6]

The reaction of CuCl, LiAs(SiMe₃)₂ and dppb (Bis(diphenylphosphino)butane) leads to the formation of ionic cluster complexes. Depending on the reaction conditions one can isolate [Cu₈As₃(AsSiMe₃)₂(dppb)₄]⁺[Cu{As₂(SiMe₃)₂}{As₄(SiMe₃)₄}]^‐ ( 1 ) and [Cu₈As₃(AsSiMe₃)₂(dppb)₄]⁺[Cu{As(SiMe₃)₂}₂]^‐ ( 2 ). The same reaction of CuCl, dppm (Bis(diphenylphosphino)methane) and LiSb(SiMe₃)₂ leads to the neutral cluster complex [Cu₁₀(Sb₃)₂(SbSiMe₃)₂(dppm)₆] ( 3 ). The structures of 1‐3 have been solved by X‐ray single crystal analyses.     

Selenolate gold complexes with aurophilic Au(I)-Au(I) and Au(I)-Au(III) interactions

The gold(I) selenolate compound [Au(2)(SePh)(2)(mu-dppf)] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) has been prepared by reaction of [Au(2)Cl(2)(mu-dppf)] with PhSeSiMe(3) in a molar ratio 1:2. This complex reacts with gold(I) or gold(III) derivatives to give polynuclear gold(I)-gold(I) or gold(I)-gold(III) complexes of the type [Au(4)(mu-SePh)(2)(PPh(3))(2)(mu-dppf)](OTf)(2), [Au(3)(C(6)F(5))(3)(mu-SePh)(2)(mu-dppf)], or [Au(4)(C(6)F(5))(6)(mu-SePh)(2)(mu-dppf)], with bridging selenolate ligands. The reaction of [Au(2)(SePh)(2)(mu-dppf)] with 1 equiv of AgOTf leads to the formation of the insoluble Ag(SePh) and the compound [Au(2)(mu-SePh)(mu-dppf)]OTf. The complexes [Au(4)(C(6)F(5))(6)(mu-SePh)(2)(mu-dppf)] and [Au(2)(mu-SePh)(mu-dppf)]OTf (two different solvates) have been characterized by X-ray diffraction studies and show the presence of weak gold(I)-gold(III) interactions in the former and intra- and intermolecular gold(I)-gold(I) inter-actions in the later.