Primary amino-functionalized N-heterocyclic carbene ligands as support for Au(I)···Au(I) interactions: structural, electrochemical, spectroscopic and computational studies of the dinuclear [Au2(NH2(CH2)2imMe)2][NO3]2

The N-heterocyclic carbene (NHC) precursor, 1-(2-aminoethyl)-3-methylimidazolium nitrate, [NH(2)(CH(2))(2)imMe)]NO(3) ([3][NO(3)]) reacted with Ag(2)CO(3) in dimethyl sulfoxide readily yielding a Ag(I)-(NHC-NH(2)) complex presenting limited stability in solution. The in situ carbene transfer reaction of the latter with [Au(tht)Cl] afforded the first example of a dinuclear gold(I) complex [Au(2)(NH(2)(CH(2))(2)imMe)(2)][NO(3)](2) ([5][NO(3)](2)) bearing a primary amino-functionalized NHC ligand. The complex has been characterized by NMR, mass spectrometry, X-ray crystallography and cyclic voltammetry; the electrochemical behaviour and photophysical properties of [5][NO(3)](2) have been also investigated and the experimental data have been compared with density functional theory (DFT) and Time Dependent (TDDFT) calculations. Single-crystal structural studies showed that the Au(I)-carbene compound contains dinuclear (AuL)(2) cations in which pairs of gold(I) centres are linked by a pair of bridging ligands, with a Au···Au aurophilic contact of 3.2332(17) ? that is maintained in solution as documented by the DFT calculations. Complex [5][NO(3)](2) is photoluminescent in solution at room temperature and the high energy emission peak at 410 nm is remarkably shifted with respect to the absorption band centered at 260 nm.     

Highly selective ion probe for Al3+ based on Au(I)···Au(I) interactions in a bis-alkynyl calix[4]arene Au(I) isocyanide scaffold

A bis-alkynyl calix[4]arene Au(I) isocyanide complex has been synthesized and demonstrated to be a selective ion probe for Al(3+) based on Au(I)Au(I) interactions.     

Modulation of luminescence by subtle anion-cation and anion-π interactions in a trigonal Au(I)···Cu(I) complex

The trigonally coordinated [AuCu(PPh(2)py)(3)](BF(4))(2) (1) crystallizes in two polymorphs and a pseudopolymorph, each of which contains a trigonally coordinated cation with short Au(I)-Cu(I) separations of ～2.7 ?. Under UV illumination, these crystals luminesce different colors ranging from blue to yellow. The structures of these cations are nearly superimposable, and the primary difference resides in the relative placement of the anions and solvate molecules. As confirmed by time-dependent density functional theory calculations, it is these interactions that are responsible for the differential emission properties.     

Concerted halogen and hydrogen bonding in [RuI2(H2dcbpy)(CO)2]···I2···(CH3OH)···I2···[RuI2(H2dcbpy)(CO)2

A new type of concerted halogen bond-hydrogen bond interaction was found in the solid state structure of [RuI(2)(H(2)dcbpy)(CO)(2)]···I(2)···(MeOH)···I(2)···[RuI(2)(H(2)dcbpy)(CO)(2)]. The iodine atoms of the two I(2) molecules interact simultaneously with each other and with the OH group of methanol of crystallization. The interaction was characterized by single crystal X-ray measurements and by computational charge density analysis based on DFT calculations.     

Covalent Bonding in Au(BO) 2 − and Au(BS) 2 −

We perform in this work a comprehensive first-principles investigation on the geometric and electronic structures of Au(BO) ₂ ^? and Au(BS) ₂ ^? which are valent isoelectronic to the well-known Au(CN) ₂ ^? monoanion. Au(BO) ₂ ^? and Au(BS) ₂ ^? complexes prove to possess linear ground-state structures similar to Au(CN) ₂ ^? and the BO^? and BS^? ligands in them are found to be coordinated terminally via boron atoms to gold centers which are weakly negatively charged. Au–B bonds in Au(BO) ₂ ^? and Au(BS) ₂ ^? appear to have higher Wiberg bond indices (0.79 and 0.80) and more covalent components (60 and 53 %) than the corresponding values of Au–C interaction in Au(CN) ₂ ^? (0.67 and 39 %, respectively) at the same theoretical levels. Their Au–B bifurcation values of the electronic localization function also turn out to be higher than Au–C. These results strongly suggest that the Au–B bonds in Au(BO) ₂ ^? and Au(BS) ₂ ^? with multiple-bond character possess stronger covalent characters than Au–C in Au(CN) ₂ ^? .     

Structural organization and dimensionality at the hands of weak intermolecular Au···Au, Au···X and X···X (X = Cl, Br, I) interactions

The salts K[AuCl(2)(CN)(2)]·H(2)O (1), K[AuBr(2)(CN)(2)]·2H(2)O (2) and K[AuI(2)(CN)(2)]·?H(2)O (3) were synthesized and structurally characterized. Compound 1 crystallizes as a network of square planar [AuCl(2)(CN)(2)](-) anions separated by K(+) cations. However, 2 and 3 feature 2-D sheets built by the aggregation of [AuX(2)(CN)(2)](-) anions via weak, intermolecular X···X interactions. The mixed anion double salts K(3)[Au(CN)(2)](2)[AuBr(2)(CN)(2)]·H(2)O (4) and K(5)[Au(CN)(2)](4)[AuI(2)(CN)(2)]·2H(2)O (5) were also synthesized by cocrystallization of K[Au(CN)(2)] and the respective K[AuX(2)(CN)(2)] salts. Similarly to 2 and 3, the [Au(CN)(2)](-) and [AuX(2)(CN)(2)](-) anions form 2-D sheets via weak, intermolecular Au(I)···X and Au(I)···Au(I) interactions. In the case of 5, a rare unsupported Au(I)···Au(III) interaction of 3.5796(5) ? is also seen between the two anionic units. Despite the presence of Au(I) aurophilic interactions of 3.24-3.45 ?, neither 4 nor 5 exhibit any detectable emission at room temperature, suggesting that the presence of Au(I)···X or Au(I)···Au(III) interactions may affect the emissive properties.     

某些Au(III)、Au(I)配离子在溶液中扩散的研究

用毛细管色谱在25℃测定了AuCl4、[Au(SO3)2]、[Au(CSN2H4)2]、[Au(CN)2]等配位体离子在HCl溶液中的扩散系数及AuCl4阴离子的扩散活化能, 并与文献中其它配阴离子的D值比较, 认为扩散离子的质量和所载电荷可能是决定配阴离子扩散系数的主要因素.     

Amalgamating at the molecular level. A study of the strong closed-shell Au(I)···Hg(II) interaction

Complex {[Hg(C(6)F(5))(2)][Au(C(6)F(5))(PMe(3))](2)}(n)2 displays unsupported Au(I)···Hg(II) and Au(I)···Au(I) interactions. Its crystal structure displays a polymeric -(Au-Hg-Au-Au-Hg-Au)(n)- disposition. Ab initio calculations show very strong Au(I)···Hg(II) and Au(I)···Au(I) closed-shell interactions of -73.3 kJ mol(-1) and -57.0 kJ mol(-1), respectively, which have a dispersive (van der Waals) nature and are strengthened by large relativistic effects (>20%).     

Au(II)化合物[Au(CH_2)_2PH_2]_2X_2(X=F,Cl,Br,I)的量子化学理论研究

采用从头计算HF,MP2方法和密度泛函理论,对Au(II)系列化合物[Au(CH2)2PH2]2X2(X=F,Cl,Br,I)的几何结构、电子结构和振动频率进行了研究.研究表明Au的5d和6s电子参与Au—Au以及Au—X之间的成键.Au—Au,Au—X键强烈的电子相关作用使HF方法不适于该体系的研究,BP86和B3LYP两种泛函给出较大的Au—Au和Au—X键长,而MP2方法和局域的密度泛函方法则给出了合理的结构参数.局域密度泛函方法计算得到的Au—Au键和Au—X键振动频率也与实验数据符合较好.还运用含时密度泛函理论计算了[Au(CH2)2PH2]2X2的电子激发能,对分子在紫外-可见光谱范围内的电子跃迁进行了分析,考察了卤素配体对激发能的影响,并结合分子轨道能级的变化对此给予了解释.     

Re-investigation of Barium-Gold(I)-Tetra-Thiostannate(IV), Ba[Au2SnS4], with Short AuI···AuI Separation Showing Luminescence Properties

New investigations combining single crystal- and synchrotron-based powder X-ray diffraction data revealed that Ba[Au₂SnS₄] crystallizes in the orthorhombic crystal system in space group C222₁ instead of P2₁2₁2 as reported earlier. While the principle crystal structure is not altered, there are significant differences of the interatomic distances Au-S and Sn-S. A salient property of this crystal structure is the partial framework composed of AuS₂ dumbbells and SnS₄ tetrahedra to form chains [(Au₂SnS₄)^2–]_∞ propagating in the [100] direction. Within the chains a short Au ··· Au separation of 2.9538(13) Å is observed, while the interchain Au ··· Au separation is longer at 3.383 Å. The Ba²⁺ cation is eightfold coordinated by S^2– anions in a distorted bicapped trigonal prismatic environment BaS₈. These polyhedra share all S^2– anions thus generating a three-dimensional network. This connection Scheme generates voids along [100] hosting [(Au₂SnS₄)^2–]_∞ chains. In addition, the compound has been shown to be luminescent at the blue-green spectral range with emission maximum at approximately 21000 cm^–1.     

A Silver(I)–Gold(II) Hexanuclear Guanidinate–Benzoate Cluster with Short Au–Au Bonds

Abstract  Attempts to remove the halide atoms from [Au₂(hpp)₂Cl₂], 1, Hhpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, with Ag(I) benzoate lead to the formation of the Au(I)–Ag(I) product, [(PhCOO)₂Au₄(hpp)₄Ag₂(PhCOO)₄], 2. This material is stable to air and light at room temperature and shows a UV–vis spectrum in THF with absorbances at 575, 440, 345, and 273 nm. The mixed metal product crystallizes as green crystals in the monoclinic space group P2₁/n. The Au–Au distances of 2.4473(19) ? are the shortest gold–gold distances reported to date. The gold···silver distance is 3.344(3) ? and the silver···silver distance is 2.771(6) ?. This latter distance is short compared with the Ag···Ag distance of 2.902(3) ? in the eight-membered silver benzoate dimer starting material. The Au(II) hpp and Ag(I) benzoate components are linked by carboxylate groups and two gold-silver interactions. This result stands in structural contrast to terminal carboxylate products observed with Au(II) ylides and amidinates wherein the carboxylate is not bridging to another metal atom. Index Abstract  Three equivalents of silver benzoate react with [Au₂(hpp)₂Cl₂], 1, Hhpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, to form the gold(II)-silver(I) product, 2, [(PhCOO)₂Au₄(hpp)₄Ag₂(PhCOO)₄]. The gold–gold distance of 2.4473(19) ? is the shortest gold–gold distance reported to date. The gold–silver distance is 3.344(3) ? and the silver–silver distance is 2.771(6) ?. Dedicated to the memory of F. Albert Cotton (1930–2007).     

H2C[P(Ph)2AUX]2和HC[P(Ph)2AUX]3(X=I,CI)型配合物的构象和Au (I)-Au(I)相互作用的从头算研究

根据配合物H₂C[P(Ph)₂AUX]₂(X=I,CI)和HC[P(Ph)₂AUX]₃(X=I,CI)的晶体结构对它们进行了从头算研究,在MP2近似水平下得到绕C-P旋转所产生构象的势能曲线,从而揭示AU(I)－AU(I)相互作用. 计算结果表明,在所研究的四个配合物中均存在AU(I)-AU(I)相互作用,该作用较弱,约为10. 0～16. 5kJ/mol,与Schmibaur的实验估计值和Pyykko等对其它模型配合物的计算结果接近.     

Au(I)、Ag(I)、Cu(I)氰合离子在大孔强碱性阴离子交换树脂中的传质研究

测定了不同温度下Au(Ⅰ)、Ag(Ⅰ)、Cu(Ⅰ)氰合离子分别在大孔强碱性苯乙烯系CN、Cl、OH型离子交换树脂中的内扩散系数和扩散活化能。从结果得出,氰合离子在树脂相中扩散传质异常缓慢并非由于过高的活化能,而可能是由于过低的活化熵所致。     

1,2,4-Triphospholyl gold(I) and copper(I) complexes: synthesis,crystal and molecular structures of [Cu(PMe3)2(μ-P3C2tBu2)(μ-I)Cu(PMe3)2], [Cu(PMe3)2(μ-P3C2tBu2)2Cu(PMe3)2] and [Au(η1-P3C2tBu2)2][Au(PEt3)2]

Treatment of K(P₃C₂^tBu₂) with Cu₂I₂ and PMe₃ gave the binuclear complex [Cu(PMe₃)₂(μ-P₃C₂^tBu₂)₂Cu(PMe₃)₂] via the isolated intermediate compound [Cu(PMe₃)₂(μ-P₃C₂^tBu₂)(μ-I)Cu(PMe₃)₂]. The reaction of K(P₃C₂^tBu₂) with [AuCl(PEt₃)] on the otherhand gave the cation:anion complex [Au(PEt₃)₂][Au(η¹-P₃C₂^tBu₂)₂]. All complexes were fully characterised by multinuclear spectroscopy and single crystal X-ray diffraction studies.     

Hydrocarboxylation of isoprene catalyzed by iodo-carbonylrhodium derivatives. Spectroscopic evidence for participation of H+ ··· Rh(CO)2I2− tight ion pairs and cis-Rh(CO)2(H2O)I in catalysis

Hydrocarboxylation of isoprene catalyzed by iodocarbonylrhodium derivatives is described. Either 4-methyl-3-pentenoic (pyroterebic) acid or its lactone derivative (γ,γ-dimethyl-γ-butyrolactone) can be selectively produced in high yield depending on the experimental conditions. Spectroscopic evidence indicates the possible participation of H⁺ ··· Rh(CO)₂I₂⁻ tight ion pairs and/or cis-Rh(CO)₂(H₂O)I in the catalysis. The identification of these two new species is based on spectroscopic investigation of the interconversion reactions between solvent-separated [H₃O]⁺[Rh(CO)₂X₂]⁻ ions and [Rh(CO)₂X]₂ (X = Cl, I).     

Crystal structures of the selenium- and bromo-bridged copper(I) dimers [Cu2(μ2-Br)2(SePPh3)2 · (NCCH3)2] and [Cu2I2(μ3-dppm-Se,Se)2] · 2CH3CN

Reactions of copper(I) halides with Se-donor ligands, namely, triphenylphosphine selenide (Ph₃PSe) and bis(diphenylselenophosphinyl)methane (dppm-Se,Se) yielded bromo-bridged [Cu₂(μ₂-Br)₂(SePPh₃)₂(NCCH₃)₂] (1), and selenium-bridged, [Cu₂I₂(μ₃-dppm-Se,Se)₂]?· 2CH₃CN (2) dimers, whose crystal structures are described. Acetonitrile stabilizes 1 by coordinating and helps to stabilize the packing in crystals of 2.     

Au(I)炔基配合物激发态性质的理论研究

用MP2方法和CIS方法分别优化了Au(I)炔基配合物及相应炔烃的基态和激发态的结构. 计算结果表明, 在基态, 分子有向中间收缩的趋势, Au(I)的修饰作用减弱了配体内部原子间的成键作用. 随着分子链长增长, Au(I)与配体间的相互作用减弱; 激发态的电子跃迁减弱了, Au(I)与配体间的相互作用, 并且这种影响随着分子链增长而更加明显. 计算得出Au(I)炔基配合物体系的荧光发射光谱并发现其独特的发光性质, 说明取代H原子的—AuPH3比—H更具有离子性.     

Structural, (197)Au Mössbauer and solid state (31)P CP/MAS NMR studies on bis (cis-bis(diphenylphosphino)ethylene) gold(I) complexes [Au(dppey)(2)]X for X = PF(6), I

(197)Au M?ssbauer spectra for the d(10) gold(i) phosphine complexes, [Au(dppey)(2)]X (X = PF(6), I; dppey = (cis-bis(diphenylphosphino)ethylene), and the single crystal X-ray structure and solid state (31)P CPMAS NMR spectrum of [Au(dppey)(2)]I are reported here. In [Au(dppey)(2)]I the AuP(4) coordination geometry is distorted from the approximately D(2) symmetry observed for the PF(6)(-) complex with Au-P bond lengths 2.380(2)-2.426(2) A and inter-ligand P-Au-P angles 110.63(5)-137.71(8) degrees . Quadrupole splitting parameters derived from the M?ssbauer spectra are consistent with the increased distortion of the AuP(4) coordination sphere with values of 1.22 and 1.46 mm s(-1) for the PF(6)(-) and I(-) complexes respectively. In the solid state (31)P CP MAS NMR spectrum of [Au(dppey)(2)]I, signals for each of the four crystallographically independent phosphorus nuclei are observed, with the magnitude of the (197)Au quadrupole coupling being sufficiently large to produce a collapse of (1)J(Au-P) splitting from quartets to doublets. The results highlight the important role played by the counter anion in the determination of the structural and spectroscopic properties of these sterically crowded d(10) complexes.     

I(-)·(CH3I)2 photoexcitation: the influence of dipole bound states on detachment and fragmentation

We present the results of a photoelectron imaging study of the I(-)·(CH(3)I)(2) cluster anion over excitation wavelengths 355-260 nm. The resulting spectra and photoelectron angular distributions (PADs) suggest extensive electron-molecule interaction following photoexcitation. Fragmentation channels are observed subsequent to excitation between 355 and 330 nm. The origin of these features, which begin 200 meV and peak 70 meV below the X band direct detachment threshold, is described in terms of a predissociative dipole bound state. The nature of the fragments detected and the energetics of the channel opening argue strongly in favor of an asymmetric, head to tail cluster anion geometry posited by Dessent et al. [Acc. Chem. Res. 31, 527 (1998)]. Above the direct detachment threshold, PADs display evidence of phenomena akin to electron-molecule scattering. The fragment anions disappear above the X band threshold but reappear some distance below the second (A) direct detachment band. At these energies there is also rapid variation of the X band PAD, an observation attributed to autodetachment via spin-orbit relaxation of the iodine core of the cluster.