Structure of Aqueous Gallium(III) Bromide Solutions Over a Temperature Range 80–333 K by Raman Spectroscopy, X-ray Absorption Fine Structure, and X-ray Diffraction

The structure and complex formation of concentrated aqueous gallium(III) bromide (GaBr₃) solutions have been investigated over a temperature range 80–333 K by Raman spectroscopy, X-ray absorption fine structure (XAFS), and X-ray diffraction. The Raman spectra obtained at various [Br^?]/[Ga³⁺] molar ratios and temperatures have shown that complex formation between Ga³⁺ and Br^? occurs as a predominant species, with [GaBr₄]^? at [Ga³⁺] as high as 1～2 M (M = mol?dm ^?3) and [Br^?]/[Ga³⁺] ratios > ～2, and that cooling of the solutions favors the formation of the aqua Ga³⁺. The intermediate species were not seen in the Raman spectra. The XAFS data have revealed that the aqua complex has a sixfold coordination as [Ga(H₂O)₆]³⁺ with a Ga³⁺–H₂O distance of (1.96 ± 0.02) Å, whereas the [GaBr₄]^? complex has a Ga³⁺–Br^? distance of (2.33± 0.02) Å, and that vitrification of the aqueous GaBr₃ solution at liquid nitrogen temperature shifts the equilibrium toward the aqua complex. The X-ray diffraction data at different subzero temperatures have shown a tendency of decreasing Ga³⁺–Br^? and increasing Ga³⁺–H₂O interactions with lowering temperature, confirming the preference of aqua Ga³⁺ in the supercooled liquid state as well as in the glassy state. The Ga³⁺–H₂O distance of ～1.8 Å for the tetrahedral coordination was found in a 2.01 M gallium(III) bromide solution with a [Br^?]/[Ga³⁺] ratio of 3.7 and gradually increased to a value of 1.92 Å for octahedral geometry with decreasing temperature, suggesting that equilibrium shifts from [GaBr₄]^? to [Ga(H₂O)₆]³⁺ through intermediate species, [GaBr _n ]^(3?n)+ (n = 2 and 3). The Ga³⁺–Br^? and Br^?–Br^? distances within [GaBr₄]^? with an almost tetrahedral symmetry are (2.35± 0.02) and (3.82± 0.03) Å, respectively. The Ga³⁺ has the second hydration shell at (4.03± 0.03) Å and the hydration of Br^? is characterized with a Br^?–H₂O distance of (3.35± 0.02) Å at all temperatures investigated.     

Structure and Reactivity of Iron(0)-Phenyltellurolate [PPN][PhTeFe(CO)4]

Anionic iron(0) tetracarbonyl with terminal phenyltellurolate ligand PhTe^?, [PhTeFe(CO)₄]^?, has been synthesized and characterized. The title compound was obtained by addition of (PhTe)₂ to [PPN][HFe(CO)₄] THF solution dropwise. [PPN][PhTeFe(CO)₄] crystallizes in the monoclinic space group C c, with a = 16.119(4) Å, b = 13.141(3) Å, c = 19.880(8) Å, β = 93.04(3)°, V = 4205(2) ų, and Z = 4. The [PhTeFe(CO)₄]^? anion is a trigonal-bipyramidal complex in which the phenyltellurolate ligand occupies an axial position with Fe-Te bond length 2.630(5) Å and the Fe-Te-C(Ph) angle is 103.4(5)°. The neutral iron(0)-telluroether compound, (PhTeMe)Fe(CO)₄, was prepared by alkylation of the [PhTeFe(CO)₄]^?. Protonation of [PhTeFe(CO)₄]^?and reaction of H₂Fe(CO)₄ and PhTe)₂ ultimately lead to formation of the known dimer Fe₂(μ-TePh)₂(CO)₆ and H₂.     

Crystal structure of tris(ethylenediamine)cobalt(III) (aqua)hexachloromercurate(II) chloride [Co(En)3]2[Hg2(H2O)Cl6]Cl4

The compound [Co(En)₃]₂[Hg₂(H₂O)Cl₆]Cl₄ (I, En is ethylenediamine) has been synthesized and studied by X-ray diffraction. The crystals of I (a = 21.8745(14) Å, b = 10.6008(6) Å, c=15.4465(12) Å, space group Pna2₁) consist of tris(ethylenediamine)cobalt(III) complexes (the unit cell contains two [Co(En)₃]³⁺ cations of opposite chirality). [Hg₂(H₂O)Cl₆]^2? anions, and isolated chloride ions. The complex anion consists of the tetrahedral [HgCl₄]^2? group (Hg-Cl, 2.44–2.56 Å) and the hydrated molecule [Hg(H₂O)Cl₂] (Hg-Cl, 2.301 and 2.308 Å; Hg-O, 2.788 Å) combined by weak Hg-Cl interactions (2.915 and 3.220 Å).     

Darstellung und Kristallstruktur von Tris(äthylendiamin)kobalt(III)-trichlorostannat(II)-dichlorid, [Co(en)3][SnCl3]Cl2

Preparation and Crystal Structure of Tris(ethylenediamine) cobalt(III)-trichlorostannate(II)-dichloride, [Co(en)₃] [SnCl₃]Cl₂ The title compound has been prepared from [Co(en)₃]Cl₃ and SnCl₂ · 2H₂O in aqueous HCl solution. It crystallizes in the orthorhombic space group Pbca, with a = 21.906(7), b = 10.607(3), c = 15.356(7) Å. The crystal structure has been determined from 1606 independent reflections by Patterson snd Fourier syntheses, and has been refined by least squares methods to R = 0.074. The [Co(en)₃]³⁺ ion is found to have the conformation of Λ(δδλ) resp. Δ(λλδ). The structure of the [SnCl₃]^? ion corresponds to a distorted tetrahedron, in which one site is occupied by the stereochemically active 5s electron pair. The following Sn? Cl distances have been found 2.493(7), 2.492(5), 2.479(7) Å, the distances of the two anionic Cl atoms from Sn are >4 Å.     

Zirconiumphthalocyanine: Darstellung und Eigenschaften chloridhaltiger Phthalocyanine des drei- und vierwertigen Zirconiums; Kristallstruktur von cis-Di(triphenylphosphin)iminium-tri(chloro)phthalocyaninato(2–)zirconat(IV)-di(dichlormethan)

Zirconiumphthalocyanines: Synthesis and Properties of Chloride Ligated Phthalocyanines of Ter- and Quadrivalent Zirconium; Crystal Structure of cis-Di(triphenylphosphine)iminium-tri(chloro)phthalocyaninato(2–)zirconate(IV)-di(dichloromethane) cis-Di(chloro)phthalocyaninato(2–)zirconium(IV) is obtained by the reaction of ZrCl₄ with phthalodinitrile in 1-chloronaphthaline at 230°C. It reacts with molten di(triphenylphosphine)iminiumchloride ((PNP)Cl) yielding cis-di(triphenylphosphine)iminium-tri(chloro)phthalocyaninato(2-)zirconate(IV), cis-(PNP)[ZrCl₃Pc^2?]. This crystallizes with two molecules of dichloromethane in the monoclinic space group P2₁/n with the lattice constants a = 15.219(4) Å, b = 20.262(10) Å, c = 20.719(4) Å, b? = 93.46(2)°, Z = 4. The seven coordinated Zr atom is situated in a “square base-trigonal cap” polyhedron. The plane of the three chlorine atoms runs parallel to the plane of the four isoindole nitrogen atoms N_iso. The Zr–Cl distances range from 2.49 to 2.55 Å, the Zr? N_iso distances from 2.26 to 2.29 Å. Due to ion packing effects the Pc^2? ligand shows an asymmetrical convex distortion. The PNP cation adopts the bent conformation. The P? N? P angle is 139°, the P? N distance 1.58 Å. As confirmed by the cyclovoltammograms cis-(PNP)[ZrCl₃Pc^2?] is oxidized (anodically or chemically by Cl₂) to yield cis-tri(chloro)phthalocyaninato(1–)zirconium(IV) and reduced (cathodically or chemically by [BH₄]^?) yielding chlorophthalocyaninato(2–)zirconium(III) and cis-di(triphenylphosphine)iminium-di(chloro)phthalocyaninato(2–)zirconate(III). The optical spectra show the typical π–π*-transitions of the Pc^2? resp. Pc^? ligand not much affected by the different states of oxidation and coordination of zirconium. The same is true for the vibrational spectra of the Pc^2? resp. Pc^? ligand. In the f.i.r. spectra between 350 and 150 cm^?1 the asym. and sym. Zr? Cl stretching and Cl? Zr? Cl deformation vibration as well as the asym. Zr? N stretching vibration of the [ZrCl_xN₄] skeleton (x = 1–3) is assigned.     

Darstellung und Eigenschaften von Diphthalocyaninaten des Bismuts, [Bi(Pc)2]k (k = 1−, 0, 1+); Kristallstruktur von gemischtvalentem [Bi(Pc)2] · CH2Cl2

Synthesis and Properties of Diphthalocyaninates of Bismuth, [Bi(Pc)₂]^k (k = 1?, 0, 1+); Crystal Structure of mixed-valent [Bi(Pc)₂] · CH₂Cl₂ Blue di(phthalocyaninato(2-))bismuthate(III), [Bi(Pc^2?)₂]^?, is obtained by the reaction of BiO(NO₃) with molten 1,2-dicyanobenzene in the presence of potassium methylate and isolated as tetra-n-butylammonium (ⁿBu₄N)⁺ and bis(triphenylphosphine)iminium (PNP)⁺ salt. Green mixed-valent [Bi(Pc)₂] · CH₂Cl₂ is prepared by anodic oxidation of [Bi(Pc^2?)₂]^?. It crystallizes in the orthorhombic γ modification (Pnma; a = 28.176(5), b = 22.913(3), c = 7.925(1) Å, Z = 4). The Bi^III ion is eightfold coordinated by the N_iso atoms of the slightly distorted Pc ligands in a square antiprismatic manner. The average Bi? N_iso bond distance is 2.467 Å. The complex is paramagnetic (μ_eff = 1.84 μ_B). Oxidation of [Bi(Pc^2?)₂]^? with bromine yields purple, diamagnetic [Bi(Pc^?)₂]Br_x (1.5 ≤ x ≤ 2.5). The redox properties are investigated electrochemically. UV-Vis-NIR, MIR/FIR and resonance Raman spectra of the new bismuth(III) complexes are discussed and compared with those of diphthalocyaninates of the lanthanides.     

Structural Systematics for Lanthanide(III) Systems: Lattice Interactions in Salts [CoL3][Ln(dipic)3]·nH2O (L = N,N′‐Aromatic Bidentate Ligand; dipic = Dipicolinate = pyridine‐2,6‐dicarboxylate) Containing Complex Ions of D3 Symmetry

Structural characterisation of a number of hydrated solids containing chiral, kinetically inert [Co(A–A)₃]³⁺ cations (A–A = 2,2′‐bipyridine, 1,10‐phenanthroline, 4,4′‐dimethyl‐2,2′‐bipyridine) and chiral, kinetically labile [Ln(dipic)₃]^3– anions (Ln = La, Eu, Tb, Ho, Er, Lu, Y, though not for all cobalt cations; dipic = dipicolinate = pyridine‐2,6‐dicarboxylate) show a remarkable range of associations between the lattice components, though all are racemic arrays. Analysis of the structures in terms of short interatomic contacts between the components shows that, whereas numerous contacts of the heteroaromatic ligands do occur, very few define an arrangement which could be truly termed “π‐stacking” where the rings are closely parallel and atom overlaps in projection are substantial. Water is important in the highly hydrated lattice structures, not only because of hydrogen‐bonding interactions with itself and carboxylate‐O atoms but also because of its interactions with the aromatic units. The family [Co(bipy)₃][Ln(dipic)₃]·~13H₂O are essentially isomorphous for the full range of Ln plus Y (triclinic, P\bar{1} , a = 12.3, b = 14.3, c = 16.5 Å, α = 94, β = 94, γ = 108 ?, Z = 2). Among the heavier lanthanides, the potential symmetry of the anion/cation combination is realised in the trigonal space group P\bar{3} , both species lying together as an ion‐pair, disposed on the trigonal axis for [Co(phen)₃][Ln(dipic)₃]·22H₂O (Ln = Eu, Er; a = 15.2, c = 16.8 Å, Z = 2).     

Oxidative Addition of Diphenyl Disulfide/Thiophenol to [Mn(CO)5]−: Crystal Structure of cis-[Mn(CO)4(SPh)2]−

Oxidative addition of diphenyl disulfide to the coordinatively unsaturated [Mn(CO)₅]^? led to the formation of low-spin, six-coordinate cis-[Mn(CO)₄(SPh)₂]^?. The complex cis-[PPN][Mn(CO)₄(SPh)₂] crystallized in monoclinic space group P2₁/c with a = 9.965(2) Å, b = 24.604(5) Å, c = 19.291(4) Å, β = 100.05(2)°, V = 4657(2)ų, and Z = 4; final R = 0.036 and R_w = 0.039. Thermal transformation of cis-[Mn(CO)₄(SPh)₂]^? to [(CO)₃Mn(μ-SPh)₃Mn(CO)₃]^? was completed overnight in THF at room temperature. Additionally, reaction of [Mn(CO)₅]^? and PhSH in 1:2 mole ratio also led to cis-[PPN](Mn(CO)₄(SPh)₂]. Presumably, oxidative addition of PhSH to [Mn(CO)₄]^? was followed by a Lewis acid-base reaction to form cis-[Mn(CO)₄(SPh)₂]^? with evolution of H₂.     

Fluorine Containing Coordination Compounds of CrIII. I. Crystal and Molecular Structure of trans-[Cr(en)2F2] · ClO4

Trans-[Cr(en)₂F₂]ClO₄ (en = 1,2-diaminoethane) has triclinic P1 space group with a = 5.633(1), b = 8.879(2), c = 11.686(2) Å, α = 99.92(2), β = 87.22(2), γ = 100.02(2)° and Z = 2. The unit cell contains two independent trans-Cr(en)₂F₂⁺ cations and ClO₄^? anion. Average Cr? F bond length is 1.88(1) Å. Cr? N bonding distances are from 2.05 to 2.10 Å. Mean Cl? O distance is 1.36 Å. 1,2-diaminoethans are in the gauche conformation. Trans-[Cr(en)₂F₂]Cl and [Cr(en)₂F₂]Br have monoclinic and orthorhombic space groups with four equivalent Cr(en)₂F₂⁺ cations. Trans-[Cr(en)₂F₂]I forms twinned crystals preventing further crystallographic investigation.     

The solid state reaction between hexaamminechromium(III) complexes and L-α-alanine

The solid reaction between [Cr(NH₃)₆]X₃(X^? = Cl, I, SCN and NO₃) and L-α-alanine was studied under continuous rise in temperature and isothermal heating. Under continuous rise in temperature, the main products were [Cr(NCS)₃-(NH₃)₃] (X^? = NCS) and [Cr(L-ala)₃] (X^? = NO₃), when [Cr(NH₃)₆]Cl₃ and [Cr(NH₃)₆]I₃ as starting complexes were used; in both cases only the decomposition proceeds. Under isothermal heating at 150°C the main products were [CrCl(NH₃)₅]-Cl₂ (X^? = Cl), [Cr(NH₃)₆]I₂ (X^? = I), [Cr(NCS)₃(NH₃)₃] (X^? = SCN) and [Cr(L-ala)₃] (X^? = NO₃). In those matrix reactions, the ease of anion coordination was: SCN^? > Cl^? > I^? > alanine. For the synthesis of tris(alaninato)chromium(III) complex the most desirable starting complex was [Cr(NH₃)₆](NO₃)₃.The solid state reaction between [Cr(en)₃]X₃ type complexes and NH₄X (X^? = F, Cl, Br, I and SCN), KX (X^? = Cl, Br and I), and NaSCN have been reported by Wendlandt and Stembridge¹. They reported that the reaction product in most cases, was cis-[Cr(en)₂Y₂]X, where Y and X are the same or different anions, depending upon the matrix material employed and the thermal matrix method appears to be a useful new route for the synthesis of bis(ethylendiamine(chromium(III) complexes.In the previous paper², the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-amino acids has been utilized in the preparation of tris(amino acidato)chromium(III) complexes. The preparation of [Cr(L-ala)₃] by the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-alanine have been reported. No studies on the effect of the counter-ion have been reported.In this paper, various hexaamminechromium(III) complexes, [Cr(NH₃)₆]X₃ (X^? = Cl, I, SCN and NO₃), were heated with L-α-alanine under continuous rise in temperature and under isothermal heating at 150°C for studies on the ease of anion coordination. It will seen that the anion which replaces the ammonia in the hexaamminechromium(III) complex comes from either the alanine or counter-ion.     

Darstellung und Kristallstruktur von Tetraphenylphosphonium-Hexathiocyanatorhodat(III), [P(C6H5)4]3[Rh(SCN)6]

Preparation and Crystal Structure of Tetraphenylphosphonium Hexathiocyanatorhodate(III), [P(C₆H₅)₄]₃[Rh(SCN)₆] By treatment of RhCl₃ · n H₂O with KSCN in water a mixture of the linkage isomers [Rh(NCS)_n(SCN)_6–n]^3?, n = 0–2 is formed which is separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-ray structure determination on a single crystal of [P(C₆H₅)₄]₃[Rh(SCN)₆] (monoclinic, space group C1c1, a = 13.620(5), b = 22.929(13), c = 22.899(9) Å, β = 98.55(3)°, Z = 4) confirms the coordination of all ligands via S with the middle Rh? S distance of 2.372 Å and Rh? S? C angles of 109°. The SCN groups are nearly linear with 175° and averaged bondlengths S? C 1.63 and C? N 1.14 Å. The crystal lattice is build up by layers of complex anions and voluminous cations with no specific interactions but which are closely connected by thiocyanate ligands and phenyl rings.     

Synthesis,Characterization and X‐ray Crystal Structure of a Chromium(III) Complex Obtained from a Proton‐Transfer Compound Containing 1,10‐Phenanthroline‐2,9‐dicarboxylic Acid and 2,6‐Pyridinediamine

The novel 1,10‐phenanthroline‐2,9‐dicarboxylate containing Chromium(III) complex, (pydaH)[Cr(phendc)₂] · 5H₂O, was synthesized using proton‐transfer compound LH₂, (pydaH₂)²⁺(phendc)^2?, (pyda: 2,6‐pyridinediamine; phendcH₂: 1,10‐phenanthroline‐2,9‐dicarboxylic acid) and thoroughly characterized by elemental analysis, IR spectroscopy, X‐ray crystallography and cyclic voltammetry. The complex crystallizes in the monoclinic space group P2₁/n with four formula units in the unit cell. The unit cell dimensions are: a = 13.962(3) Å, b = 14.529(3) Å, c = 16.381(3) Å and β = 106.691(4)°. In this complex, 1,10‐phenanthroline‐2,9‐dicarboxylate acts as a tridentate ligand and the lattice is composed of anionic hexacoordinated complex, [Cr(phendc)₂]^?, 2,6‐pyridiniumdiamine counter ion, (pydaH)⁺, and five lattice water molecules. Crystallographic characterization revealed that the resulting supramolecular structure is strongly stabilized by complicated network of hydrogen bonds between the crystallization water molecules, counter ion and both coordinated and uncoordinated carboxylate groups. There is no relevant π‐π interaction for this anionic complex between pyda or phendc moieties. The electrochemical studies indicated over potential for both the cathodic and anodic peaks of the complex with respect to the free Cr³⁺ ion, as a consequence of the energy requirement for rearrangement of the ligand at electrode surface.     

Gas-phase chemistry of electron deficient organometallic anions: the reactions of [Cr(CO)3]− ˙ and [Cr(CO)4]− ˙ with aldehydes,ketones, esters and ethers

Reactions in the gas phase of the 13- and 15-electron radical anions [Cr(CO)₃]^{? ˙} and [Cr(CO)₄]^{? ˙} with a series of 27 aldehydes, ketones, esters and ethers have been examined. Sequential alkane eliminations and metal-bonded CO ligand displacements were the principal reactions identified for the RCHO/[Cr(CO)₃]^{? ˙} systems with the latter reaction also common to the RCHO/[Cr(CO)₄]^{? ˙} systems. While [Cr(CO)₄]^{? ˙} was generally unreactive towards ketones R · R'CO, the principal products identified for [Cr(CO)₃]^{? ˙}/ketone reactions were the metal-decarbonylated species, respectively [R · R'CO · Cr(CO)_x]^{? ˙} with x = 0–3, and [R · (R' - H₂)CO · Cr(CO)₂]^{? ˙}. The reaction of [Cr(CO)₃]^{? ˙} with esters RCOOR' proceeds via metal insertion into the alkoxy C? O bond to give end products of the type [R'O · Cr · R(CO)₂]^? and [R'O? Cr(CO)₃]^? while the sole ionic products of dialkyl ether/[Cr(CO)₃]^{? ˙} reactions were identified as the alkoxytricarbonylchromium species [RO · Cr(CO)₃]^?.     

A chromium(III) bis-acetylide complex containing a trans-diethyl-ethylenedithio-substituted tetrathiafulvalene (TTF) derivative: synthesis,crystal structures,and magnetic properties

A new Cr(III) bis-acetylide complex containing redox-active ethynyl-substituted 4-methyl-4′,5′-trans-diethyl-ethylenedithio-tetrathiafulvalene, [Cr(III)cyclam(C≡C-MeEt₂EDT-TTF)₂]ⁿ⁺ ([1]ⁿ⁺) was synthesized. The crystal structures of two salts, [1][Ni(dmit)₂] (dmit?=?2-thioxo-1,3-dithiole-4,5-dithiolate) and [1][Ni(mnt)₂]₃ (mnt?=?maleonitriledithiolate), were determined by single-crystal X-ray diffraction. In the crystal of [1][Ni(dmit)₂], the trans-diethyl group of [1]⁺ is in the axial position and prevents π-stacking of the TTF units, resulting in a negligibly weak spin–spin interaction between Cr³⁺ and [Ni(dmit)₂]^?. In contrast, in [1][Ni(mnt)₂]_3, the trans-diethyl group is in the equatorial position in [1][Ni(mnt)₂]₃ owing to the strong attractive force between the π-stacked TTF⁺ units and the [Ni(mnt)₂]^? anions. This π-stacking has a significant effect on the magnetic property of [1] [Ni(mnt)₂]₃. The π-stacked TTF⁺ units and [Ni(mnt)₂]^? anions behave approximately as a one-dimensional S?=?1/2 antiferromagnetic chain connecting the spins of Cr³⁺ antiferromagnetically.

     

Protonation and Hydrogen Atom Abstraction Reactions in the Synthesis of the [HP7M(CO)3]2– Ions (M = Cr,W)

Ethylenediamine (en) solutions of [P₇M(CO)₃]^3– (M = Cr, W) react with weak acids to give [HP₇M(CO)₃]^2– ions where M = Cr ( 4 a ) and W ( 4 b ) in high yields. Competition studies with known acids revealed a pK_a range for 4 b in DMSO of 17.9 to 22.6. The [P₇M(CO)₃]^3– complexes also react with one-half equivalent of I₂ to give 4 through an oxidation/hydrogen atom abstraction process. Labeling studies show that the abstracted hydrogen originates from the [K(2,2,2-crypt)]⁺ ions or from the solvent (DMSO-d₆) in the absence of [K(2,2,2-crypt)]⁺ or other good hydrogen atom donors. In the solid state, the ions have no crystallographic symmetry but in solution they show virtual C_s symmetry (³¹P NMR spectroscopy) due to an intramolecular wagging process. Crystallographic data for [K(2,2,2-crypt)]₂[HP₇W(CO)₃]: triclinic, P 1, a = 10.9709(8) Å, b = 13.9116(10) Å, c = 19.6400(14) Å, α = 92.435(6)°, β = 93.856(6)°, γ = 108.413(6)°, V = 2831.2(4) ų, Z = 2, R(F) = 7.65%, R(wF²) = 14.17% for all 7400 reflections. For [K(2,2,2-crypt)]₂[HP₇Cr(CO)₃]: triclinic, P 1, a = 12.000(3) Å, b = 14.795(3) Å, c = 17.421(4) Å, α = 93.01(2)°, β = 93.79(2)°, γ = 110.72(2)°, V = 2877(2) ų, Z = 2.     

Fluoro-containing coordination compounds of chromium(III). V. Preparation and crystal structure of the Racemic Cis-[Cr(en)2F2]ClO4 · NaClO4 · H2O

Cis-[Cr(en)₂F₂]ClO₄ · NaClO₄ · H₂O (en = 1,2-diaminoethane) was obtained as the red crystalline product from the saturated solutions of both NaClO₄ and cis-[Cr(en)₂F₂]ClO₄ in water. The compound crystallizes in the monoclinic P2₁/n (No.14) space group with a = 9.540(2), b = 11.840(2); c = 14.659(3) Å, β = 95.02(1)°, Z = 4. The unit cell of the racemic crystal contains cis-[Cr(en)₂F₂]⁺ in the Λλλ and Δδδ enantiometric forms, Na⁺, ClO₄^?, and lattice H₂O. Cr has octahedral coordination. Cr? F and Cr? N bonds are 1.868(4), 1.887(5) and from 2.067(2) to 2.100(8) Å. Mean Cl? O bond is 1.38 Å. Na⁺ ions are in the distorted octahedral environment. Infrared spectrum confirms the presence of the lattice H₂O and proves the cis structure of [Cr(en)₂F₂]⁺.     

Double complex salts [M(NH3)5Cl][M′Br4] (M = Rh, Ir, Co, Cr, Ru; M′ = Pt, Pd): Synthesis, x-ray diffraction characterization, and thermal properties

Double complex salts (DCSs) with [M(NH₃)₅Cl]²⁺ (M = Rh, Ir, Co, Cr, Ru) cations and [PtBr₄]^2? anions were prepared in high yields. The salts were two-phase mixtures of the anhydrous and monohydro DCSs. Anhydrous analogues containing [PdBr₄]^2? anions with M = Cr or Ru were synthesized. All the compounds were characterized using a set of physicochemical methods. The crystal structure of chloropentaamminechromium(III) tetrabromopalladate(II) was solved: space group Pnma, Z = 4, a = 17.068(2) Å, b = 8.315(12) Å, c = 9.653(14) Å. The [M(NH₃)₅Cl][M′X₄] (M = Rh, Ir, Co, Cr, Ru; M′ = Pd, Pt; X = Cl, Br) compounds were shown to be isostructural. The [M(NH₃)₅Cl][PtBr₄] · H₂O monohydrates are isostructural to the [M(NH₃)₅Cl][PdCl₄] · H₂O monohydrates (space group P2₁/c, z = 4). The properties of the compounds were comparatively analyzed. The tendencies of the thermal stability of the complexes were elucidated. The thermolysis products of the double complex salts obtained under a helium or hydrogen atmosphere were studied.     

Synthesis,magnetic property and DNA cleavage behavior of a new dialkoxo‐bridged diiron(III) complex

A new dialkoxo‐bridged diiron(III) complex, [Fe₂(BMA)₂(CH₃O)₂Cl₂]·2Cl·4CH₃OH ( 1 ) [BMA = N,N‐bis(2‐benzimidazolylmethyl)amine], was synthesized and characterized by UV‐visible absorption and infrared spectra and magnetic susceptibilities. The complex crystallizes in the monoclinic system, space group P2(1)/n, a = 12.9659(19) Å, b = 10.0278(16) Å, c = 17.919(2) Å, β = 93.766(8)° , V = 2324.8(6) ų, Z = 2, F(000) = 1036, D_c = 1.426 g cm^?3, µ = 0.908 mm^?1. According to X‐ray crystallographic studies, each Fe(III) ion lies in a highly distorted octahedral environment, and two Fe(III) ions are bridged by the methoxyl oxygens. Cryomagnetic analyses indicated a moderate antiferromagnetic interaction between the high‐spin Fe(III) ions, with J = ? 27.05 cm^?1. Moreover, the binding interaction of DNA with the diiron complex was investigated by spectroscopic and agarose gel electrophoretic methods, showing moderate cleavage activity on pBR322 plasmid DNA at physiological pH and temperature. Copyright © 2007 John Wiley & Sons, Ltd.     

A unique example of a co-crystal of [Ag(atr)2][Cr(dipic)2] (dipic = dipicolinate; atr = 3-amino-1H-1,2,4-triazole) and dinuclear [Cr(H2O)(dipic)(μ-OH)]2, with different coordination environment of Cr(III) ions

Treatment of a neutral aqueous solution of dipicolinic acid (dipicH₂), 3-amino-1H-1,2,4-triazole (atr) and CrCl₃·6H₂O in the presence of AgNO₃ (in molar ratio 1:1:1:3) under hydrothermal condition led to the formation of a co-crystal of {[Ag(atr)₂][Cr(dipic)₂]}₂·[Cr(H₂O)(dipic)(μ-OH)]₂·4H₂O (1). Compound 1 was characterized by elemental analyses, IR and UV-Vis spectroscopy as well as X-ray diffraction studies. The structure consists of two [Ag(atr)₂]⁺ cations, two [Cr(dipic)₂]⁻ anions, one co-crystallized neutral dinuclear chromium(III) complex, [Cr(H₂O)(dipic)(μ-OH)]₂, and four co-crystallized water molecules. Silver(I) ion in [Ag(atr)₂]⁺ is coordinated by two monodentate 3-amino-1H-1,2,4-triazole ligands, bound via endocyclic nitrogen atoms, in a linear fashion. Chromium(III) ion is octahedrally coordinated by two O,N,O-tridentate dipicolinate ligands in anionic complex. Each chromium(III) ion in neutral dinuclear complex, [Cr(H₂O)(dipic)(μ-OH)]₂, is octahedrally coordinated by one O,N,O-tridentate dipicolinate ligand, one water molecule and two bridging μ-OH ions in cis position. Thermal methods (TGA/DTA) confirm the number of co-crystallized water molecules in 1.     

Benzeneselenolates of Mercury(II). Crystal and Molecular Structures of [Hg(SePh)2] and (Bu4N)[Hg(SePh)3]

The reaction of dibenzenediselenide, (SePh)₂, with mercury in refluxing xylene gives bis(benzeneselenolato)mercury(II), [Hg(SePh)₂], in a good yield. (ⁿBu₄N)[Hg(SePh)₃] is obtained by the reaction of [Hg(SePh)₂] with a solution of [SePh]^– and (ⁿBu₄N)Br in ethanol. The solid state structures of both compounds have been determined by X-ray diffraction. The mercury atom in [Hg(SePh)₂] (space group C2, a = 7.428(2), b = 5.670(1), c = 14.796(4) Å, β = 103.60(1)°) is linearly co-ordinated by two selenium atoms (Hg–Se = 2.471(2) Å, Se–Hg–Se = 178.0(3)°). Additional weak interactions between the metal and selenium atoms of neighbouring molecules (Hg…Se = 3.4–3.6 Å) associate the [Hg(SePh)₂] units to layers. The crystal structure of (ⁿBu₄N)[Hg(SePh)₃] (space group P2₁/c, a = 9.741(1), b = 17.334(1), c = 21.785(1) Å, β = 95.27(5)°) consists of discrete complex anions and (ⁿBu₄N)⁺ counter ions. The coordination geometry of mercury is distorted trigonal-planar with Hg–Se distances ranging between 2.5 and 2.6 Å.