Die Pyridinaddukte der Goldhalogenide. 1. Darstellung und Struktur von [Hpy][AuCl4], AuCl3 · py, [AuCl2(py)2]Cl · H2O und [AuCl2(py)2][AuCl2]

Pyridine Adducts of the Gold Halides. 1. Synthesis and Structure of [Hpy][AuCl₄], AuC1₃ · py, [AuCl₂(py)₂]Cl · H₂O, and [AuCl₂(py)₂] [AuCl₂] HAuCl₄ reacts with pyridine in aqueous solution to form sparingly soluble [Hpy] [AuCl₄]. This goes into solution as [AuCl₂(py)₂]⁺ on adding an excess of pyridine. [Hpy][AuCl₄] decomposes above 195°C to HCl and AuCl₃ · py, which can also be obtained from NaAuCl₄ and pyridine. AuCl₂ · py is formed by the reaction of AuCl₂ · S(CH₂C₆H₄)₂ with pyridine in CHCl₃. According to the vibrational spectrum the complex is built up of trans[AuCl₂(py)₂]⁺ cations and [AuCl₂]^? anions. The IR spectra of [Hpy][AuCl₄], AuCl₃ · py, and [AuCl₂(py)₂]Cl · H₂O are discussed and assigned with respect to the crystal structures. [Hpy][AuCl₄] crystallizes monoclinic in the space group C2/m. In its structure alternating layers of [Hpy]⁺ cations and [AuCl₄]^? anions are observed. The monoclinic AuCl₃ · py (space group C2/c) consists of molecular complexes, wherein the gold atom is surrounded by three Cl atoms and one pyridine molecule in a square planar arrangement. The coordination is completed to an elongated octahedron by two more distant Cl atoms of neighbouring complexes. [AuCl₂(py)₂]Cl · H₂O crystallizes in the monoclinic space group P2₁/n. It forms planar trans[AuCl₂(py)₂]⁺ cations, weakly coordinated with an additional Cl^? ion and one H₂O molecule. The Au? Cl bond lengths in the complexes under investigation are in the range of 227 to 229 pm, the Au? N distances are between 197 and 199 pm.     

The Tetrachloridoaurates(III) of Zinc(II) and Cadmium(II)

The first salt‐like compounds of dications with [AuCl₄]^– anions are reported. The compounds Zn[AuCl₄]₂ · (AuCl₃)_1.115 ( 1 ) and Cd[AuCl₄]₂ ( 2 ) are obtained from reactions of MCl₂ (M = Zn, Cd) and elemental gold in liquid chlorine at ambient temperature under autogenous pressure and subsequent annealing at 230 °C. The structure of 1 represents an incommensurately modulated composite [superspace group C2/c(α0γ)0s] built of two subsystems. The first subsystem contains chains of zinc(II) tetrachloridoaurate(III), which feature a slightly distorted octahedral coordination of Zn and can be described by the Niggli formula ¹_∞{Zn[AuCl₄]_1/1[AuCl₄]_2/2}. The second subsystem consists of Au₂Cl₆ molecules, which are located in channels built up by the first subsystem. The structural parameters of the hosted Au₂Cl₆ molecules show only small deviations from neat AuCl₃. The crystal structure of Cd[AuCl₄]₂ ( 2 ) consists of chains built of Cd²⁺ ions coordinated by bridging [AuCl₄]^– anions and alternating Cd‐Au sequence. Cd has a distorted octahedral coordination environment.     

Polynuclear complexes of gold(III) of the composition ([Au(S2CNR2)2][AuCl4])n (R = C4H9, R2 = (CH2)5): Synthesis, supramolecular structures, and thermal behavior

The interaction of binuclear cadmium dialkyldithiocarbamates [Cd₂(S₂CNR₂)₄] with solutions of AuCl₃ in 2M HCl gives polynuclear gold(III) complexes ([Au(S₂CNR₂)₂][AuCl₄]) _n , where R = C₄H₉ (I) and R₂ = (CH₂)₅ (II). The structures of the synthesized compounds solved by X-ray diffraction analysis are char-acterized by a complicated organization at the supramolecular level. The structures are based on polymer chains (I) and layers (II) involving isomeric cations [Au(S₂CNR₂)₂]⁺ and anions [AuCl₄]⁻. The thermal behavior of the synthesized complexes is studied by simultaneous thermal analysis including thermogravimetry and differential scanning calorimetry. The final product of the thermal transformations of the studied complexes is shown to be reduced metallic gold.     

[M(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl][AuCl<Subscript>4</Subscript>]Cl · <Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O (M = Rh,Ru, or Cr): Synthesis,crystal structure,and thermal properties

Double complex salts [M(NH₃)₅Cl][AuCl₄]Cl · nH₂O (M = Rh, Ru, or Cr) were synthesized and structurally studied. These compounds are isostructural; space group C2/m. Their crystal structure is built of [M(NH₃)₅Cl]²⁺ complex cations, [AuCl₄]^? complex anions, Cl^? anions, and molecules of water of crystallization. The compounds were characterized by X-ray crystallography, X-ray powder diffraction, IR spectroscopy, and thermal analysis.     

Oxidation – Reduction Reactions of Tetrachloroaurate(III) Anion with Triphenyl Derivatives of Group V Elements

The reduction of the tetrachloroaurate (III) anion by L (L = PPh₃, AsPh₃, SbPh₃) is quantitative in non-aqueous solution. The products are the gold(I)-complexes AuClL (L = AsPh₃, SbPh₃) and Au(PPh₃)⁺₂ together with the corresponding oxidation product LCl₂. Kinetic studies show that the reactions are first order in AuCl^?₁ and L. In addition a path independent of PPh₃ was found in dichloromethane. These data are interpreted in terms of mechanisms which involve reduction of AuCl^?₄ to AuCl^?₂ followed by equilibrium formation of AuClL for L = AsPh₃ and SbPh₃. For PPh₃, the data are consistent with a chloride replacement by PPh₃ to give AuCl₃ PPh₃, which is followed by a rapid reduction by a second mole of PPh₃. Equilibrium formation constants are reported for several Au(I) complexes.     

Interaction of copper(II) halides with 4-azafluorene derivatives in neutral and acid media. Crystal and molecular structure of 4-aza-9-oxofluorenium tetrabromocuprate hydrate (HL<Superscript>4</Superscript>)<Subscript>2</Subscript>CuB<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

Complexes of copper(II) halides (chlorides and bromides) with some 4-azafluorene derivatives have been synthesized and studied by X-ray crystallography and IR and UV spectroscopy. In neutral media, Cu(L)₂X₂ (X = Cl, Br) complexes are formed in which the ligands are coordinated to the metal atoms though the lone pair of the endocyclic nitrogen atom and through the oxygen atoms of substituents. In acid media at pH 2, (HL²)₂CuX₄ complexes are formed in which the 4-azafluorene molecules protonated at the endocyclic nitrogen atom act as an outer-sphere cation. The molecule and crystal structure of 4-aza-9-oxofluorenium tetrabromocuprate hydrate (HL⁴)₂CuBr₄·H₂O has been determined.     

Synthesis and crystal structure of [ReO(ahp)2(PPh3)]Cl (Hahp=2-amino-3-hydroxypyridine): a novel cationic monooxorhenium(v) complex

The cationic complex [ReO(ahp)₂(PPh₃)]⁺ was isolated as the chloride salt from the reaction of trans-[ReOCl₃(PPh₃)₂] and 2-amino-3-hydroxypyridine (Hahp) in ethanol. Coordination of the chelates only occurs through the amino nitrogen and the phenolate oxygen of ahp^?. The X-ray crystal structure shows a distorted octahedral geometry, in which a phenolate oxygen coordinated trans to the oxo group and the rhenium atom is displaced by 0.2520(1) Å out of the mean equatorial plane towards the oxo oxygen.     

Influence of heterocycles arrangement in structural isomeric ligands on coordination sphere of copper(II) complexes: Crystal structures and spectroscopic characterization

New copper complexes with two structural isomeric ligands, 2-(indazol-1-yl)-2-thiazoline (TnInA) and 2-(indazol-2-yl)-2-thiazoline (TnInL), have been synthesized and characterized by magnetic measurements, IR, electronic and EPR spectroscopies. Moreover, the molecular structures of [Cu(NO₃)(TnInA)₂(H₂O)](NO₃) · (H₂O) (1) and [Cu(NO₃)₂(TnInL)(H₂O)] (2) have been resolved by single-crystal X-ray diffraction studies. In compound 1 the copper ion is in a distorted octahedral geometry, with the equatorial plane formed by four nitrogen donor atoms from two organic ligands and the axial positions occupied by two oxygen atoms from a water molecule and a mono-coordinated nitrate anion. The coordination geometry around the copper atom in compound 2 can be described basically as a square pyramid with two nitrogen atoms from TnInL ligand, one oxygen atom from a water molecule and one oxygen atom from a nitrate group in the equatorial plane. The axial position is occupied by one oxygen atom from a nitrate group. Likewise, a second oxygen atom from the last nitrate group in equatorial position might involve in a weak sixth coordination position to give a (4 + 1 + 1^∗) coordination mode.     

über den Mechanismus der Extraktion von Gold(III) mit gesÄttigten aliphatischen Monoketonen

It has been found, that gold(III) is extracted by way of a hydrate-solvated mechanism from a hydrochloric acid medium with aliphatic ketones (in the presence or absence of a solvent). When the methylethylketone is used as an extractant, the solvate has the following composition:M ⁺(H₂O)_3–14 (MEK)₇AuCl₄ ^?, whereM ⁺=H⁺, Li⁺, K⁺, Na⁺, NH₄ ⁺. If the cation is a heavy non-solvated ion, for instance N(C₂H₅)₄ ⁺, the solvate is free of water. The active extractant solvates also the anion AuCl₄ ^?, a fact which could explain the high values of the coefficient of distribution.     

Transfer of the chelating ligands in the systems [LAuCl2]+-[PdCl4]2−: Synthesis and structure of the salt (NH4)0.20[(Bipy)AuCl2]1.04[(Bipy)PdCl2]0.96[AuCl4]0.76[PdCl4]0.24

The formation of binary complex salts containing gold(III) in the cation and palladium(II) in the anion in the systems [(Bipy)AuCl₂]⁺-[PdCl₄]^2? occurs by transfer of the N,N-electron-donating chelating ligand bipyridine and the chloride ligands between the gold-containing cation and the palladium-containing anion. The resulting neutral salt [(Bipy)PdCl₂] crystallizes together with the anion [AuCl₄]^? from acetonitrile-water (1 : 1-1 : 2, v/v) to give the complex salt (NH ₄ ⁺ )_0.20[(Bipy)AuCl ₂ ⁺ ]_1.04[(Bipy)PdCl₂]_0.96[AuCl ₄ ^? ]_0.76PdCl ₄ ^2? ]_0.24 with a total Au : Pd ratio of 3 : 2. The ammonium cation is formed from acetonitrile upon its hydrolysis most likely catalyzed by Pd complexes. Quantum-chemical calculations were performed to study the transfer of the chelating ligand theoretically.     

Hybrid inorganic–organic layered structures of [AuCl4] and protonated bipyridyl derivatives

Complexes of [AuCl₄]⁻ with 4,4′-dipyridylethane, 4,4′-dipyridylethene and 4,4′-bipyridine-N,N′-dioxide have been prepared by a solvent layering method. All three complexes pack in distinct organic and inorganic layers: [H₂-dpa][AuCl₄]Cl (1) and [H₂-dpe][AuCl₄]Cl (2) are isostructural and consist of layers of [AuCl₄]⁻ anions alternating with hydrogen-bonded dipyridyl?Cl?dipyridyl layers. In [H-bpdo][AuCl₄] (3), the organic layers consist instead of hydrogen-bonded bipyridyldioxide cations. This structure is the first report of a structure containing protonated 4,4′-bipyridine-1,1′-dioxide.     

Theoretical study of the relative stabilities of H+(X)2 and H+(X)3 conformers and their clustering energies: X  CO and N2

Third-order Møller–Plesset perturbation theory (MP 3) with a 6-31G** basis set was applied to study the relative stabilities of H⁺(X)₂ conformations (X ? CO and N₂) and their clustering energies. The effect of both basis set extensions and electron correlation is not negligible on the relative stabilities of the H⁺(CO)₂ clusters. The most stable conformation of H⁺(CO)₂ is found to be a C_∞v structure in which a carbon atom of CO bonds to the proton of H⁺(CO), whereas that of H⁺(N₂)₂ is a symmetry D_∞h structure. The second lowest energy conformations of H⁺(CO)₂ and H⁺(N₂)₂ lie within 2 kcal/mol above the energies of the most stable structures. Clustering energies computed using MP 3 method with the 6-31G** basis set are in good agreement with the experimental findings of Hiraoka, Saluja, and Kebarle. The low-lying singlet conformations of H⁺(X)₃ (X ? CO and N₂) have been studied by the use of the Hartree–Fock MO method with the 6-31G** basis set and second-order Møller–Plesset perturbation theory with a 4-31G basis set. The most stable structure is a T-shaped structure in which a carbon atom of CO (or a nitrogen atom of N₂) attacks the proton of the most stable conformation of H⁺(X)₂ clusters.     

The ternary metal mixed ligand complexes formed by benzimidazole and N, N-bis(2-hydroxyethyl) glycine

The stability constants of the ternary M(Bic)(Bzim)~ complexes, where M~(2 )=Cu~(2 ), Ni~(2 ) or Zn~(2 ), Bic~-=the anion of N, N-bis(2-hydroxyethyl) glycine and Bzim = benzimidazole, were determined by potentiometric pH titration in aqueous solution. One of them (M~(2 ) = Cu~(2 )) was also separately determined by spectrophotometry. The results show that these ternary complexes are stabler than expected on statistical grounds. The enhanced stability of the ternary M(Bic) (Bzim)~ complexes is attributed to the π_A-π_B cooperative effect between Bic~- and benzimidazole. Besides, compared with Cu(Bic) (Bzim)~ and Ni(Bic) (Bzim)~ , the ternary Zn(Bic)(Bzim)~ complex has relatively high stability. The crystal structure of [Cu(Bic)(Bzim)]ClO_4 was determined by single crystal X-ray diffraction techniques. The copper atom has a trigonal-bipyramidal geometry, the basal plane is formed by an oxygen atom of the carboxylato group and two hydroxyl oxygen atoms, the apical position is occupied by a nitrogen a     

Electrochemical synthesis and structure of 2-amino-1-ethylbenzimidazole adducts of copper,cobalt, and zinc chelates in the N,N,S ligand environment

2-Amino-1-ethylbenzimidazole (L¹) adducts with copper(II), cobalt(II), and zinc(II) chelates of N,N,S tridentate tosylamino-functionalized mercaptopyrazole-containing Schiff base (H₂L), resulting from condensation of 2-tosylaminoaniline with 1-phenyl-3-methyl-4-formylpyrazole-5-thiol, with the general formula [ML · L¹] were obtained by electrochemical method. The structure and composition of the complexes were confirmed by the data of C, H, N elemental analysis, IR and ¹H NMR spectroscopy, and magnetochemical and X-ray spectral measurements. The mononuclear structure of the copper(II) adduct with coordination bond located on the pyridine type endocyclic nitrogen atom of 2-amino-1-ethylbenzimidazole was proved by X-ray diffraction.     

Crystal Structure of Hexafluosilicates of Protonated Thiosemicarbazide and 2,5-Diamino-1,3,4-thiadiazole Produced in the Reaction of Thiosemicarbazide with Fluosilicic Acid

The structure of the crystal complex (L¹H)₂(L²H)(SiF₆)_1.5(L¹is thiosemicarbazide, L²is 2,5-diamino-1,3,4-thiadiazole) was studied by X-ray diffraction analysis. The complex was prepared by reacting an aqueous solution of L¹with 45% fluosilicic acid. The crystals are monoclinic: a= 16.080(3) Å, b= 5.4860(8) Å, c= 20.079(4) Å, = 91.46(1)°, Z= 4, space group P2/n, R= 0.0427. The components of the ionic structure of the complex are L¹H⁺and L²H⁺cations and SiF^2– ₆anions combined by a system of H bonds of the NH···S and NH···F types, the -nitrogen atom of the hydrazine fragment and the endocyclic nitrogen atom of the heterocycle being the protonation centers in L¹H⁺and L²H⁺, respectively. The bond lengths in the SiF^2– ₆anions range within 1.621(6)–1.691(2) Å.     

Crystal and molecular structure of iodoprotatrane: Tris(2-hydroxyethyl)ammonium iodide

By X-ray diffraction the crystal and molecular structure of iodoprotatrane (tris(2-hydroxyethyl)ammonium iodide I[HN(CH₂CH₂OH)₃]⁺ (IP) at 120 K and 293 K is determined. The IP cation, as in all protatranes, has the endo conformation. The N-H bond is surrounded by three CH₂CH₂OH groups. The stability of this configuration is explained by the intramolecular trifurcated inductive interaction with three oxygen atoms through the space of the nitrogen atom. In the IP crystal packing, each iodine anion is linked by three strong OH...I (2.63 Å) and three weak I...H (3.13 Å) hydrogen bonds with six cations from the CH₂N group. This indicates a greater nucleophilicity of the iodine atom.     

Tin(IV) complexes with 2-hydroxybenz-(2-hydroxynaphth)aldehyde picolinoylhydrazones (H2Ps, H2Pnf). Crystal structure of [SnCl3(Ps · H)] · CH3OH and [SnCl3(Pnf · H)] · CH3OH

The reactions of SnCl₄ with picolinoylhydrazones of 2-hydroxybenz-(2-hydroxynaphth)aldehydes (H₂Ps, H₂Pnf) in CH₃OH gave non-electrolyte complexes [SnCl₃(Ps · H)] · CH₃OH (I) and [SnCl₃(Pnf · H)] · CH₃OH (II). The imide form of the ligand coordinated to Sn(IV) through the azomethine nitrogen atom and oxyazine and oxy oxygen atoms was proved by UV/Vis, IR, and ¹H NMR spectroscopy. The negative charge on the coordination unit thus arising is counterbalanced by the positive charge caused by the protonation of ligands at the pyridine nitrogen atom of the heterocycle. It was shown that dehydrochlorination of the complexes affords tin-containing species, which correlates with the presence of the corresponding peaks [SnCl₂(Ps)]⁺ and [SnCl₂(Pnf)]⁺ in their mass spectra. The molecular and crystal structures of complexes I and II were determined by X-ray diffraction.     

Reaction of [P3N3Cl4(NH2)2] with [HN(POCl2)2]; The crystal structure of the phosphazenium salt [P3N3HCl4(NH2)2]+[N(POCl2)2]−

The reaction of diaminotetrachloro-cyclotriphosphazene with tetrachloride of μ-imino-diphosphoric acid leads to the formation of the salt-like compound [P₃N₃HCl₄(NH₂)₂]⁺[N(POCl₂)₂]⁻ which identity was unambiguously established by means of X-ray structure analysis. The structure is composed of [P₃N₃HCl₄(NH₂)₂]⁺ cations and [N(POCl₂)₂]⁻ anions joined by a system of H-bonds. As in other phosphazenium salts, the protonation of the ring N atom leads to significant changes in the endocyclic P N bond lengths.     

Niederkoordinierte phosphorverbindungen: XXXXIII. Methylenphosphane und phosphinomethylenphosphane als η2-liganden in nickel(0)-ko]mplexen

The complex (η²-ClPCTms₂)₂NiCO (II) has been prepared and its structure was determinated by X-ray analysis. With Ni(CO)₄ the 1,2-diphosphapropenes (IVa,b) form the η¹ complexes (Va,b), which could be identified by NMR spectroscopy. At room temperature Va,b dimerize to the novel complexes VIa,b, in which the phosphine atom of IVa,b acts as a η¹ and the PC bond as a η² ligand towards the Ni atom. The structure of VIa was also determinated by X-ray analysis.     

Field measurements of bottom boundary layer processes and sediment resuspension in the Changjiang Estuary

2,4-Bis(3,5-dimethylpyrazol-1-yl)-6-methoxyl-1,3,5-triazine(bpt) has been synthesized by using a new, simple and general method with high yields. Reactions of bpt with Ni(ClO₄)₂·6H₂O and Zn(ClO₄)₂·6H₂O in methanol gave mononuclear complex [Ni(bpt)₂]· (ClO₄)₂·H₂O and ternary complex [Zn(mpt)₂(dmp)](ClO₄)₂ respectively, where mpt (2,4-dimethoxy-6-(3,5-dimethyl- pyrazol-1-yl)-1,3,5-triazine) and dmp(3,5-dimethylpyrazole) are the alcoholysis products of bpt in the presence of Zn²⁺ ion. A possible mechanism for this catalytic reaction was proposed. X-ray crystal structure for ligand bpt, Ni and Zn complexes are reported. The protonated form of the ligand bpt crystallizes as its perchlorate salt including one molecule of water, [Hbpt·H₂O·ClO₄]. The proton is located on one pyrazole N-atom. [Hbpt·H₂O·ClO₄], in which [Hbpt]⁺ is in cis-cis conformation, are packed in slipped stacks of approximately parallel layers. The Π -Π overlap interactions between the non-protonized pyrazoles of the adjacent layers give a zigzag arrangement of the planar aromatic [Hbpt]⁺ molecules. In [Ni(bpt)₂](ClO₄)₂·H₂O, bpt are meridionally three-coordinated with Ni²⁺. The coordination sphere around Ni²⁺ is a slightly distorted square bipyramid, where four pyrazole nitrogen atoms occupy the basal positions and two triazine nitrogen atoms the apical one. In [Zn(mpt)₂(dmp)](ClO₄)₂, the Zn atom is coordinated with a pair of bidentate mpt ligands and one monodentate dmp ligand, forming a distorted trigonal bipyramid, where the two triazine nitrogen atoms of mpt and one nitrogen atom of dmp occupy the basal positions, and the two pyrazole nitrogen atoms of mpt the apical one.