Crystal structures of <Emphasis Type="Italic">trans</Emphasis>-dichlorobis(ethylendiamine) rhodium(III) with univalent anions

The crystal structures of the compounds trans-[Rh(en)₂Cl₂]Cl₂ · H₅O₂ (I), trans-[Rh(en)₂Cl₂]ClO₄ (II), and trans-[Rh(en)₂Cl₂]ReO₄ (III) are determined. The crystal data are: I, a = 10.860(3) Å, b = 7.795(2) Å, c = 9.023(3) Å; β = 111.56(10)°, P2₁/c space group, Z = 4, d _x = 1.875 g/cm³; II, a = 6.593(2) Å, b = 8.309(3) Å, c = 11.922(4) Å, α = 83.55(10)°, β = 79.80(10)°, γ = 75.38(10)°, P \(\bar 1\) space group, Z = 2, d _x = 2.106 g/cm³; III, a = 6.533(2) Å, b = 16.391(4) Å, c = 12.411(3) Å; β = 98.30(10)°, P2₁/c space group, Z = 4, d _x = 2.749 g/cm³. The compounds are examined by IR spectroscopy and powder XRD. The solubility of the isolated crystalline phases in water decreases in the following order: trans-[Rh(en)₂Cl₂]Cl₂·H₅O₂ > trans-[Rh(en)₂Cl₂]ClO₄ > trans-[Rh(en)₂Cl₂]ReO₄.     

Crystal structure of [Ir(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl]<Subscript>2</Subscript>[OsCl<Subscript>6</Subscript>]Cl<Subscript>2</Subscript>. Crystal-chemical analysis of the iridium-osmium system

The [Ir(NH₃)₅Cl]₂[OsCl₆]Cl₂ binary complex salt has been prepared, and its structure was investigated by single crystal X-ray diffraction. Crystal data: a = 11.1901(13) Å, b = 7.9138(13) Å, c = 13.4384(18) Å; β = 99.640(3)°, V = 1190.0(2), space group C2/m, Z = 2, FW = 1099.47, d _x = 3.068 g/cm³. Thermolysis products of [Ir(NH₃)₅Cl]₂[OsCl₆]Cl₂, [Ir(NH₃)₅Cl][OsBr₆], (NH₄)₂[OsCl₆]_x[IrCl₆]_1?x , and K₂[OsCl₆]_x[IrCl₆]_1?x were studied by X-ray phase analysis; the unit cell parameters were refined, and the dependence of volume per atom (V/Z) on the composition of the Ir Os_1?x solid solution has been plotted.     

Stability of diammine and chloroammine gold(I) complexes in aqueous solution

The substitution equilibria AuCl ₂ ^? + iNH ₄ ⁺ = Au(NH₃)_iCl_{2 ? i} + iCl^? + iH⁺, β _i ^* . were studied pH-metrically at 25°C and I = 1 mol/L (NaCl) in aqueous solution. It was found that logβ ₁ ^* = ?5.10±0.15 and logβ ₂ ^* = ?10.25±0.10. For equilibrium AuNH₃Cl_solid = AuNH₃Cl, log K _s = ?3.1±0.3. Taking into account the protonation constants of ammonia (log K _H = 9.40), the obtained results show that for equilibria AuCl ₂ ^? + iNH₃ = Au(NH₃)_iCl_{2 ? i} + iCl^?, logβ₁ = 4.3±0.2, and logβ₂ = 8.55±0.15. The standard potentials E ₀ ^1/0 of AuNH₃Cl⁰ and Au(NH₃) ₂ ⁺ species are equal to 0.90±0.02 and 0.64±0.01 V, respectively.     

Structural studies of nickel(II) complexes with 1-<Emphasis Type="Italic">tert</Emphasis>-butylimidazole-2-thione and 3-phenyl-5-methyl-pyrazole ligands

The nickel(II) complexes dichlorobis(1-tert-butylimidazole-2-thione)nickel(II) [Ni(tm ^t-Bu)₂Cl₂] (1), dinitratobis(1-tert-butylimidazole-2-thione)nickel(II) [Ni(tm ^t-Bu)₂(NO₃)₂] (2), dichloro-bis(3-phenyl-5-methyl-pyrazole)(1-tert-butylimidazole-2-thione)nickel(II) [Ni(pz^Ph,MeH)₂(tm ^t-Bu)Cl₂] (3) and dinitratobis(3-phenyl-5-methyl-pyrazole)(1-tert-butylimidazole-2-thione)nickel(II) [Ni(pz^Ph,MeH)₂(tm ^t-Bu)(NO₃)₂] (4) have been synthesized and studied. The single crystal X-ray diffraction analysis was carried out for 1 and 4 {Bruker Kappa Apex-II CCD diffractometer, MoK _α radiation}. Crystal data for 1: monoclinic C2/c, a = 16.949(2) Å, b = 8.6647(10) Å, c = 15.461(3) Å, β = 117.662(4)°, V = 2011.1(5) ų, Z = 4, D _calc = 1.460 g/cm³. Crystal data for 4: triclinic P-1, a = 9.9775(7) Å, b = 11.2254(8) Å, c = 14.8068(10) Å, α = 75.401(4)°, β = 87.422(4)°, γ = 74.874(4)°, V = 1548.86(19) ų, Z = 2, D _calc = 1.405 g/cm³. Coordination core of complex 1 adopts distorted tetrahedral geometry whereas core 4 has distorted octahedral geometry. The bonded nitrates are of two types coordinating as monodentate and bidentate ligands.     

Formation of mononuclear rhodium(III) sulfates: <Superscript>103</Superscript>Rh and <Superscript>17</Superscript>O NMR study

It was shown that the monomeric rhodium sulfate complexes [Rh(H₂O)₄(SO₄)]⁺, trans-[Rh(H₂O)₂(SO₄)₂]^?, cis-[Rh(H₂O)₂(SO₄)₂]^?, and [Rh(SO₄)₃]^3? were not predominant forms in aqueous solutions. The ¹⁰³Rh NMR chemical shifts of the complexes were assigned, and the conditions for their formation in solutions, concentration parameters, and acidity at which the fraction of the monomers was maximal were determined. The constants of formation of the complexes and ion pair (IP) were estimated: K _IP = 8 ± 3.5, K ₁ ≈ 8, K _2trans ≈ 1, K _2cis ≈ 1, and K ₃ ≈ 2.     

Crystal structure and antitumor activities of a dinuclear cobalt(II) complex based on <Emphasis Type="Italic">meso</Emphasis>-1,2,3,4-tetra(1H-benzo[<Emphasis Type="Italic">d</Emphasis>]imidazol-2-yl)butane

The [Co₂(tbb)Cl₄]?4DMF complex, where tbb is meso-1,2,3,4-tetra(1H-benzo[d]imidazol-2-yl)butane, is synthesized and characterized by single crystal X-ray diffraction. For the complex: C₄₄H₅₄Co₂C_l4N₁₂O₄, M_r = 1074.65, monoclinic crystal system, space group P21/n, a = 9.2350(13) Å, b = 11.3566(15) Å, c = 23.879(3) Å, β = 90.547(2)°, V = 2504.3(6) ų, Z = 2, D_c = 1.425 g/cm³, λ = 0.71073 Å, μ(MoK_α) = = 0.929 mm^–1, F(000) = 1112, S = 1.047, R = 0.0765, and wR = 0.2110 for 13668 observed reflections with I > 2σ(I). It is a neutral dinuclear complex. One meso-1,2,3,4-tetra(1H-benzo[d]imidazol-2-yl)butane coordinates two cobalt(II) ions. Each cobalt(II) ion is formed by two tbb nitrogen atoms and two chloride ions. The antiproliferative activities of the complex are screened by MTT assay against Eca109 cancer cells. The complex exhibits inhibition on the growth of Eca109 cancer cells with IC₅₀ of 22.1±6.7 μM after 48 h treatment. The cobalt complex has potential application in treatment of Eca109 cancer. CCDC 1015791.     

Molecular and crystal structure of a sterically distorted complex of Pd(II) with 2,9-dimethyl-1,10-phenanthroline [Pd(2,9-Me<Subscript>2</Subscript>-phen)Cl<Subscript>2</Subscript>]

A neutral complex of palladium(II) with 2,9-dimethyl-1,10-phenanthroline [Pd(2,9-Me₂-phen)Cl₂] (goldish orange colored) is examined by single crystal X-ray diffraction. The crystals of [Pd(2,9-Me₂-phen)Cl₂] are monoclinic and belong to the space group P2₁/n (a = 11.8670(7) Å, b = 7.8195(5) Å, c = 14.2418(9) Å, β = 92.5450(10)°, Z = 4, V = 1320.25 ų, R = 0.0289). The complex [Pd(2,9-Me₂-phen)Cl₂] exhibits a strong distortion of the usual square-planar geometry with a deviation of the central Pd²⁺ ion and two chloride acido-ligands from the plane of coordinated 2,9-dimethyl-1,10-phenanthroline. The lengths of two Pd-N bonds are slightly different and are 2.058 Å and 2.067 Å, the lengths of the Pd-Cl bonds are equal and are 2.285 Å. 2,9-Me₂-phen itself also suffers some distortion of the planar geometry resulting in the boat conformation of the molecule. The crystal structure of the [Pd(2,9-Me₂-phen)Cl₂] complex is characterized by the presence of π-π stacked dimers arranged in infinite tilted stacks.     

Investigation of Chloride Ion Substitution Equilibria in AuCl<Stack><Subscript>4</Subscript><Superscript>−</Superscript></Stack> with Ethylenediamine and 1,3-Diaminopropane Using Capillary Zone Electrophoresis

Substitution of chloride ions in AuCl ₄ ^? with ethylenediamine (en) and propylenediamine (tn) is studied by capillary zone electrophoresis at I = 0.05 M and T = 25°C. The substitution constants are determined: AuenCl ₂ ⁺ + en = Auen ₂ ³⁺ + 2Cl^–, logK₂ = 10.4; AuCl ₄ ^? + tn = AutnCl ₂ ⁺ + 2Cl^–, logK₁ = 16.1; AutnCl ₂ ⁺ + tn = Autn³⁺₂ + 2Cl^–, logK₂ = 12.0.     

Crystal structures of <Emphasis Type="Italic">trans</Emphasis>-[Re<Subscript>6</Subscript>S<Subscript>8</Subscript>(CN)<Subscript>2</Subscript>L<Subscript>4</Subscript>] complexes,L = pyridine or 4-methylpyridine

The structures of three novel octahedral rhenium cluster compounds [Re₆S₈(CN)₂(py)₄]·H₂O (1), [Re₆S₈(CN)₂(4-Mepy)₄] (2), [Re₆S₈(CN)₂(4-Mepy)₄]·4-Mepy (3) (py = pyridine, 4-Mepy = 4-methylpyridine) are determined by X-ray crystallography. Crystal data are: C2/m space group, a = 14.813(1) Å, b = 14.772(1) Å, c = 9.2122(6) Å, β = 119.085(2)°, V = 1761.7(2) ų, d _x = 3.318 g/cm³, R = 0.0585 (1); I4₁/amd space group, a = 16.0018(3) Å, c = 14.7186(5) Å, V = 3768.81(16) ų, d _x = 3.169 g/cm³, R = 0.0489 (2); P2₁/c space group, a = 9.0452(4) Å, b = 15.8065(7) Å, c = 15.2951(6) Å, β = 103.700(2)°, V = 2124.57(16) ų, d _x = 2.957 g/cm³, R = 0.0245 (3). Molecular cluster complexes interact via π-π stacking affording 3D frameworks in 1 and 2 and chains in 3.     

Thermodynamic Study on the Protonation and Na<Superscript>+</Superscript>, Ca<Superscript>2+</Superscript>, Mg<Superscript>2+</Superscript>-Complexation of a Biodegradable Chelant (HEIDA) at Different Ionic Strengths and Temperatures

A potentiometric method has been used for the determination of the protonation constants of N-(2-hydroxyethyl)iminodiacetic acid (HEIDA or L) at various temperatures 283.15?≤?T/K?≤?383.15 and different ionic strengths of NaCl_(aq), 0.12?≤?I/mol·kg^?1?≤?4.84. Ionic strength dependence parameters were calculated using a Debye–Hückel type equation, Specific Ion Interaction Theory and Pitzer equations. Protonation constants at infinite dilution calculated by the SIT model are \( \log_{10} \left( {{}^{T}K_{1}^{\text{H}} } \right) = 8.998 \pm 0.008 \) (amino group), \( \log_{10} \left( {{}^{T}K_{2}^{\text{H}} } \right) = 2.515 \pm 0.009 \) and \( \log_{10} \left( {{}^{T}K_{3}^{\text{H}} } \right) = 1.06 \pm 0.002 \) (carboxylic groups). The formation constants of HEIDA complexes with sodium, calcium and magnesium were determined. In the first case, the formation of a weak complex species, NaL, was found and the stability constant value at infinite dilution is log₁₀K_NaL?=?0.78?±?0.23. For Ca²⁺ and Mg²⁺, the CaL, CaHL, CaL₂ and MgL species were found, respectively. The calculated stability constants for the calcium complexes at T?=?298.15 K and I?=?0.150 mol·dm^?3 are: log₁₀β_CaL?=?4.92?±?0.01, log₁₀β_CaHL?=?11.11?±?0.02 and \( \log_{10} \beta_{\text{Ca{L}}_{2}} \)?=?7.84?±?0.03, while for the magnesium complex (at I?=?0.176 mol·dm^?3): log₁₀β_MgL?=?2.928?±?0.006. Protonation thermodynamic functions have also been calculated and interpreted.     

Application of Capillary Electrophoresis to the Study of Equilibria on an Example of Gold(III) Complexes

Three systems of gold(III) complexes in an aqueous solution (I = 0.05 M, 25°C) with slow equilibration were studied by capillary electrophoresis. It was shown on an example of mixed chloride–hydroxide complexes Au(OH) _i Cl _4-i ^- that, despite close sizes and identical charges of the forms, the mixed forms can be separated if they are kinetically inert. For the equilibria AuCl ₄ ^? + am = AuamCl ₂ ⁺ + 2Cl^– and AuamCl ₂ ⁺ + am = + Auam₂³⁺ + 2Cl^–, where am is ethylenediamine (en) and 1,3-diaminopropane (tn), the logarithmic constants were logK₂ = 10.4 for en, and logK₁ = 16.1 and logK₂ = 12.0 for tn, which satisfactorily agrees with the spectrophotometric data. There was a considerable effect of side processes, insignificant under normal conditions.     

4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Bis[dibromodichloroiron(III)]: Synthesis and Crystal Structure

A novel complex salt, namely, 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane bis[dibromodichloroiron(III)] [H₂(Crypt-222)]²⁺[FeBr₂Cl₂] ₂ ^? (I), was synthesized and structurally characterized by X-ray diffraction analysis (monoclinic crystal system, a = 13.550 Å, b = 11.018 Å, c = 12.813 Å, β = 117.52°, space group C2, Z = 2). The structure was solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.089 from 2593 independent reflections (CAD4 automated diffractometer, λMoKα radiation). In the crystal structure I, four bifurcate positions of Br and Cl in the tetrahedral anion [FeBr₂Cl₂]^? are a randomly disordered mixture of these atoms. The dication of 2.2.2-cryptand (with two protonated N atoms) in the crystallographic axis 2 contains trifurcate N⁺-H (?O)₃ hydrogen bonds.     

DNA interactions and anticancer screening of copper(II) complexes of <Emphasis Type="Italic">N</Emphasis>-(methylpyridin-2-yl)-amidino-<Emphasis Type="Italic">O</Emphasis>-methylurea

Cu(II) complexes of the tridentate ligand N-(methylpyridin-2-yl)-amidino-O-methylurea (L), namely [Cu(L)Cl₂] and [Cu(L)ClO₄]ClO₄, have been investigated for interactions with DNA by spectroscopic methods and viscosity measurements. Both complexes bind to DNA through non-intercalative interactions. [Cu(L)Cl₂] (K _b = 2.81 × 10⁵ M^?1) shows similar DNA-binding potential to [Cu(L)ClO₄]ClO₄ (K _b = 1.57 × 10⁵ M^?1). Investigation of the chemical nuclease properties toward plasmid pBR322 DNA by gel electrophoresis and atomic force microscopy (AFM) suggests that both complexes are able to cleave the supercoiled form (Form I) to the nicked (Form II) and linear forms (Form III) through an oxidative pathway. The possible reactive oxygen species have been investigated by the use of scavengers, indicating that hydroxyl radicals may be involved in the DNA cleavage mechanism. Both of these complexes show similar activities against selected human cancer cell lines.     

Synthesis and crystal structure of EnH<Superscript>2</Superscript>[IrCl<Superscript>6</Superscript>]

The preparation of EnH²[IrCl⁶] is described. Crystal data for C₂H₁₀Cl₆IrN₂ are: a = 6.8972(11) Å, b = 6.9435(16) Å, c = 7.3354(11) Å; α = 88.269(3)°, β = 65.495(2)°, γ = 60.305(2)°, V = 270.76(9) ų, space group P1, Z = 1, d_calc = 2.864 g/cm³. Crystal chemical analysis of the general motif of the structure was performed by the translation sublattice identification technique. It has been found that complex anions [IrCl₆]^2? follow the nodes of a rather regular rhombohedral subcell with the parameters a_c = 7.1 Å, α_c = 64°.     

Synthesis and crystal structure of two complexes [Cu<Subscript>2</Subscript>(NiL)<Subscript>2</Subscript>Cl<Subscript>4</Subscript>] and [Cd<Subscript>2</Subscript>(CuL)<Subscript>2</Subscript>Cl<Subscript>4</Subscript>]

Macrocyclic and supermolecular complexes [Cu₂(NiL)₂Cl₄] (I) and [Cd₂(CuL)₂Cl₄] (II) (H₂L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene) have been synthesized and structurally determined by X-ray diffraction and IR spectrum. Complex I crystallizes in the monoclinic system with P2₁/n group, a = 10.9019(15), b = 14.3589(19), c = 12.4748(17) 0A, β = 108.645(2)°, Z = 4. Complex II crystallizes in the monoclinic system with P2₁/n group, a = 10.9784(16), b = 14.580(2), c = 12.8904(18) Å, β = 109.339(2)°, Z = 4.     

The crystal structure of [Mg(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>][VO(edta)] · 3.5H<Subscript>2</Subscript>O

The crystal structure of complex [Mg(H₂O)₆][VO(edta)] · 3.5H₂O (I) was determined by X-ray diffraction study. The crystals are monoclinic, a = 6.779 Å, b = 13.373(6) Å, c = 25.054 Å, β = 96.55°, Z = 4, space group P2₁. The unit cell contains two independent [VO(edta)]^2? anions, two independent [Mg(H₂O)₆]²⁺ cations, and seven crystal-water molecules. The coordination polyhedron of each vanadium atom is formed by five donor atoms of the edta ligand (2N + 3O) (V(1)-N(1), 2.278 Å; V(1)-N(2), 2.149 Å; V(2)-N(3), 2.301 Å; V(2)-N(4), 2.165 Å; V-O(acet), 2.00 ± 0.02 Å) and the oxygen atom of the oxo group (V-O, 1.60 ± 0.01 Å). The edta ligands and the vanadium atom form three glycinate rings: two R-type rings and one G-type ring (one acetate branch remains free), as well as an E-type ring with an asymmetric gauche configuration. The [Mg(H₂O)₆] cations are slightly distorted octahedra (Mg-O, 2.013–2.132 Å, the OMgO angles are 86.6°–94.2°). The H₂O molecules form a bifurcate system of H-bonds. The crystals of compound I belong to OD-type structures with an incomplete ordering of layers.     

Synthesis and crystal structure of [Na(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>][EuL<Subscript>4</Subscript>] · 0.775CH<Subscript>2</Subscript>Cl<Subscript>2</Subscript> (HL = 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)-1,3-propanedione)

[Na(H₂O)₄][EuL₄] · 0.775CH₂Cl₂ (I) has been synthesized by the reaction of Eu(NO₃)₃ · 6H₂O with 1,3-bis(1,3-dimethyl-1H-pyrasol-4-yl)-1,3-propanedione (HL) in the presence of NaOH. Its crystal structure has been solved by X-ray diffraction analysis. Crystals are tetragonal; a = 16.2401(5) Å, c = 11.9113(4) Å, V= 3141.50(17) ų, ρ_calcd = 1.427 g/cm³, μ(MoK _α) = 1.140 mm^?1, space group P4/n, Z = 2. The structural units forming a crystal of compound I are [EuL₄]^? complex anions, [Na(H₂O)₄]⁺ cations, and CH₂Cl₂ molecules. The coordination polyhedron of the Eu atom is an Archimedean antiprism formed by the O atoms of four bidentate chelate ligands L^?.     

Tetranuclear rhenium chalcochloride cluster complexes Cs<Subscript>3</Subscript>H[Re<Subscript>4</Subscript>Q<Subscript>4</Subscript>Cl<Subscript>12</Subscript>] · 3.33H<Subscript>2</Subscript>O (Q = Se and Te): Synthesis and structures

The tetranuclear cluster rhenium complexes Cs₃H[Re₄Q₄Cl₁₂] · 3.33H₂O (Q = Te (I) and Se (II)) with the Cl atoms as terminal ligands were obtained and structurally characterized. The structures of complexes I and II were determined by X-ray diffraction analysis. Their isostructural crystals are monoclinic; space group C2, Z = 6; a = 26.403(8) Å, b = 16.495(5) Å, c = 11.744(3) Å, β = 91.25(2)°, V = 5113(2) ų (I); a = 26.573(3) Å, b = 16.461(3) Å, c = 11.726(2) Å, β = 91.381(4)°, V = 5127.6(14) ų (II).     

Thermolysis of [Pt(NH<Subscript>3</Subscript>)<Subscript>4</Subscript>][ReHlg<Subscript>6</Subscript>] (Hlg = Cl,Br). Structure refinement for [Pt(NH<Subscript>3</Subscript>)<Subscript>4</Subscript>][ReCl<Subscript>6</Subscript>]

Thermal decomposition of [Pt(NH₃)₄][ReHlg₆] binary complex salts (Hlg = Cl, Br) in a hydrogen atmosphere has been studied. Polycrystal X-ray diffractometry indicated that two-phase metallic systems are the final products of thermolysis. Structure refinement was performed for [Pt(NH₃)₄][ReCl₆] by the combined technique involving decomposition of the diffractogram into individual reflections, isolation of reflections most sensitive to the position of separate light atoms, and full-profile analysis. Crystal data for PtReN₄Cl₆H₁₂: a = 11.616(1) Å, b = 10.998(1) Å, c = 10.377(1) Å, V = 1148.1 ų, space group Cmca, Z = 4, d _x = 3.831 g/cm³. The indices are R_p = 5.48%, R_wp = 10.01%, R(F²) = 12.62%. The coordination polyhedron of Re is an almost regular octahedron: Re-Cl 2.34–2.36 Å, ∠ Cl-Re-Cl 86.9–90.3°; the coordination polyhedron of Pt is a square: Pt-N 2.04 Å, ∠N-Pt-N 90.4°.     

Structure of A Coordination Polymer [Cu(En)<Subscript>2</Subscript>CrO<Subscript>4</Subscript>]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

The crystal structure of [Cu(En)₂CrO₄]_n (En is ethylenediamine) is determined: a = 14.7359(4) Å, b = 9.8083(3) Å, c = 14.2664(4) Å, V = 2061.98(10) ų, space group Cmce, Z = 8, d_x = 1.931 g/cm³. It is demonstrated that the studied phase is isostructural with [Сu(Еn)₂SO₄]_n. A pseudotetragonal copper atom coordination (Cu–N 2.0204 Å and 2.0244 Å, ∠N–Cu–N 84.73°) is completed to distorted octahedral by two oxygen atoms of chromate anions (Cu–O 2.433 Å and 2.380 Å).