Unusual Disordering of Potassium Ions in the Structures of Cluster Rhenium Thiohalides K3[Re6S7Br7] and K4[Re6S8Cl6]

New cluster compounds — rhenium and potassium thiohalides K₃Re₆S₇Br₇ (I) and K₄Re₆S₈Cl₆ (II) — have been synthesized. Their crystal structures have been determined by single crystal X-ray diffraction. The compounds are monoclinic; (I): space group P2₁/c, a = 9.32(1) Å, b = 13.528 Å, c = 12.413 Å, β = 110.21°, Z = 2, R = 0.038; (II): space group C2/m, a = 10.614 Å, b = 17.268 Å, c = 10.448 Å, β = 110.755°, Z = 2, R = 0.042. In both structures, the potassium ions are considerably distorted. The occupancies of the potassium sites are 0.17-0.34 (I) and 0. 01-0.26 (II), correlating well with the coordination numbers (c.n. 7-10 and 2-7 for I and II, respectively). In I, adjacent positions of potassium atoms are aggregated into discrete tetrahedral and angular clusters; in II, the individual (four-and six-membered) cyclic clusters of potassium sites are present along with bent chains of vertex-and edge-sharing tetrahedral “potassium clusters.” The shortest K-K distances in these “clusters” vary from 1.31 Å to 1.54 Å (I) and from 0.66 Å to 1.65 Å (II). The “instability” of the potassium site suggests that I and II are ion conductors.Original Russian Text Copyright © 2004 by S. F. Solodovnikov, S. S. Yarovoi, Yu. V. Mironov, A. V. Virovets, and V. E. Fedorov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 909–917, September–October, 2004.     

Co-cation conduction of the (Na1-x K x )3.8M0.1P2O7 (M = Ca, Sr, Cd) solid solutions

Samples of systems (Na _1-x K _x )_3.8M_0.1P₂O₇ (M = Ca, Sr, Cd; 0 ≤x ≤ 1) are synthesized. It is established that solid solutions with the structure of γ-K₄P₂O₇ form in these systems. At room temperature, the solutions exist atx ≥ 0.7. In the calcium-containing system, they form a continuous series at temperatures exceeding ∼500°C. The co-cation character of conduction of the solutions is confirmed by measured transport numbers. The concentration dependences of the electroconductivity and its activation energy point to a polyalkali effect, which decreases with an increase in the M²⁺ ion radius. Partial conductivities of sodium and potassium cations in the (Na _1-x K _x )_3.8Ca_0.1P₂O₇ system are calculated and their dependences on the balance between alkali cations in the solid solution are discussed     

Structure determination of KScS2, RbScS2 and KLnS2 (Ln = Nd,Sm, Tb,Dy, Ho,Er, Tm and Yb) and crystal–chemical discussion

The title structures of KScS₂ (potassium scandium sulfide), RbScS₂ (rubidium scandium sulfide) and KLnS₂ [Ln = Nd (potassium neodymium sufide), Sm (potassium samarium sulfide), Tb (potassium terbium sulfide), Dy (potassium dysprosium sulfide), Ho (potassium holmium sulfide), Er (potassium erbium sulfide), Tm (potassium thulium sulfide) and Yb (potassium ytterbium sulfide)] are either newly determined (KScS₂, RbScS₂ and KTbS₂) or redetermined. All of them belong to the α‐NaFeO₂ structure type in agreement with the ratio of the ionic radii r³⁺/r⁺. KScS₂, the member of this structural family with the smallest trivalent cation, is an extreme representative of these structures with rare earth trivalent cations. The title structures are compared with isostructural alkali rare earth sulfides in plots showing the dependence of several relevant parameters on the trivalent cation crystal radius; the parameters thus compared are c, a and c/a, the thicknesses of the S—S layers which contain the respective constituent cations, the sulfur fractional coordinates z(S²⁻) and the bond‐valence sums.     

二甲基取代五元瓜环与钾离子和钆离子的配位结构

利用X-射线单晶衍射技术表征了2个二甲基取代五元瓜环(DMeQ[5])与金属离子形成的配合物的晶体结构,2个配合物分别为{[K2(H2O)3DMeQ[5]}I2.5H2O(1)和{[Gd(H2O)3][K(H2O)][(NO3)@DMeQ[5]]}(NO3)3.5H2O(2)。与DMeQ[5]和钆离子形成的配合物的结构不同的是,配合物1和2中每个DMeQ[5]端口的所有羰基氧原子都和钾离子或钆离子配位,形成全封闭结构。     

Novel μ2-oxo-bridged dinuclear aryltelluronic triorganotin(IV) esters: syntheses,structural characterizations,and in vitro cytotoxicity

Four new μ₂-oxo-bridged dinuclear aryltelluronic triorganotin esters [ArTe(μ-O)(OH)(OSnR₃)₂]₂ (Ar?=?n-propyl-Ph, R?=?Me: 1, R?=?Ph: 2; Ar?=?i-propyl-Ph, R?=?Me: 3, R?=?Ph: 4) were synthesized by reaction of μ₂-oxo-bridged dinuclear aryltelluronic acids and the corresponding R₃SnCl (R?=?Me, Ph) with potassium hydroxide in methanol. The complexes were characterized by X-ray crystallography, elemental analysis, FT-IR, and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy. The structural analysis indicates that these complexes are isostructural and crystallized as Sn₄Te₂ molecules, in which the asymmetric four-membered Te₂(μ₂-O)₂ units are situated in the center. The geometry of tellurium is described as a distorted octahedron and each tin is described as a distorted tetrahedron. Complex 2 has a 2-D network structure connected by intermolecular C–H?π interactions. Complexes 1–4 were tested for in vitro cytotoxicity against human lung cancer cells (A549) and human hepatocellular carcinoma cells (HepG2).     

Synthesis and crystal structure of potassium and manganese complexes of 1,2,3-triazole-4,5-dicarboxylic acid

Three coordination compounds [K(H₂TDA)H₂O] _n (1), [K(H₂TDA)(H₃TDA)2H₂O] _n (2), and Mn₂(phen)₂(HTDA)₂(H₂O)₄ (3) have been synthesized and characterized structurally by X-ray diffraction, where H₃TDA = 1,2,3-triazole-4,5-dicarboxylic acid and phen = 1,10-phenanthroline. Their solid-state structures have been characterized by elemental analysis and IR spectroscopy. In 1, a 3-D (4, 8)-connected metal-organic framework has been constructed using dinuclear potassium clusters as eight-connected nodes and the ligands as four-connected nodes; it represents the fluorite topology network. Compound 2 exhibits 1-D chains along c-axis, which are connected by strong hydrogen-bond interactions in 2-D layers; the layers are further stacked via hydrogen bonds in the b-direction. In 3, two neighboring Mn(II) ions are bridged by two 1,2,3-triazole-4,5-dicarboxylic groups, forming a binuclear structure, with Mn(II) ··· Mn(II) distance of 4.356 Å, which is further linked to generate a 2-D layer structure via interdimer hydrogen bonds. The fluorescence for these compounds was investigated.     

Structure of uranyl complexes with acetylenedicarboxylic acid, K(H5O2)[UO2(OOCC≡CCOO)2 · H2O] · 2H2O and Cs2[UO2(OOCC≡CCOO)2 · H2O] · 2H2O

Uranyl complexes with acetylenedicarboxylic acid, K(H₅O₂)[UO₂L₂H₂O] · 2H₂O (I) and Cs₂[UO₂L₂H₂O] · 2H₂O (II), L²⁻ = C₄O ₄ ²⁻ were prepared for the first time. The composition and structure of the complexes were determined by X-ray diffraction. The crystal data are as follows: a = 16.254(12) ?, b = 13.508(8) ?, c = 7.683(6) ?, β = 90.91(7)°, space group C2/c, V = 1687(2) ?³ (I); a = 7.0745(10), b = 18.4246(10), c = 13.1383(10) ?, space group Abm2, V = 1712.5(3) ?³ (II). The structures of I and II are based on [UO₂L₂H₂O] _n ²⁻ anionic chains stretched along the [101] direction (I) or [010] direction (II). In I and II, the uranium coordination polyhedron is a pentagonal bipyramid in which the equatorial environment of the uranyl ions is formed by the oxygen atoms of the four L²⁻ anions and the water molecule. The L²⁻ anions in I and II are bidentate bridging ligands connecting two uranium atoms that are next to each other in the anionic chain; their coordination capacity is equal to 2. In I, the K⁺ and H₅O ₂ ⁺ cations are outer-sphere species. The latter form hydrogen bonds combining the anionic chains shifted by translation b with respect to each other. The [UO₂L₂H₂O] _n ²⁻ chains in I are surrounded by the potassium and oxonium cations; in II, these are combined by hydrogen bonds into anionic layers between which Cs⁺ cations are arranged. The IR spectrum of compound II was measured and interpreted. Original Russian Text ? I.A. Charushnikova, A.M. Fedoseev, N.A. Budantseva, I.N. Polyakova, Ph. Moisy, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 1, pp. 63–69.     

Synthesis and Conformational Analysis of 1, 2-Anhydro-3, 4-di-O-benzyl-6-deoxy-α-D-glucopyranose

Abstract

The title 1, 2-anhydro sugar (10) was synthesized from methyl 4, 6-O-benzylidene-α-D-glucopyranoside or from 1, 2-O-ethylidene-α-D-glucopyranose. The key intermediate for the synthesis was 2-O-acetyl-3, 4-di-O-benzyl-6-deoxy-β-D-glucopyranosyl fluoride (8)which was transformed into the target compound by ring closure with potassium tert-butoxide. Calculations by the modified Karplus equation from vicinal coupling constants of 10 suggested that the conformation of 10 was almost an ideal ⁴ H ₅ for the pyranose ring. Conformational analysis for the 1, 2-O-(R)-ethylidene intermediates 17 and 20 revealed that their pyranose ring basically adopted a B₂,₅ conformation.     

Preparation and characterization of PEPPSI-palladium N-heterocyclic carbene complexes using benzimidazolium salts catalyzed Suzuki–Miyaura cross coupling reaction and their antitumor and antimicrobial activities

New palladium complexes were efficiently synthesized from the reaction of benzimidazolium salts 2a–e, potassium carbonate (K₂CO₃) and palladium chloride (PdCl₂) in pyridine (for 3a–e). The catalytic activity of these complexes in a catalytic system including palladium complexes and K₂CO₃ in DMF-H₂O was evaluated in Suzuki–Miyaura cross-coupling reactions of aryl bromides and chlorides with phenylboronic acid. Our novel complexes show excellent catalytic activities with high turnover numbers (TON) and high turnover frequencies (TOF) (e.g. for the Suzuki–Miyaura reaction: TON up to 370 and TOF up to 123.3?h^?1). Both benzimidazolium salts 2a–e and complexes 3 have been characterized using spectroscopic data and elemental analysis. The antimicrobial activity of the N-heterocyclic carbene palladium complexes 3a–e varies with the nature of the ligands. Also, the IC₅₀ values of both, complexes (3a–e) and benzimidazoles 2a–e, have been determined. In addition, the new palladium complexes were screened for their antitumor activity. Complexes 3e and 3d exhibited the highest antitumor effect with IC₅₀ values 6.85?μg/mL against MCF-7 and 10.75?μg/mL against T47D, respectively.     

Pharmacological properties of dicyanidoaurate(I)-based complexes: characterization and single crystal X-ray analysis

The synthesis of three bimetallic cyanido complexes with edbea [2,2′-(ethylenedioxy)bis(ethylamine)] ligand is reported. [Ni^II(μ-edbea)₂{Au(μ-CN)₂}₂]_n (1), [{Cu^II(edbea)}₂{Au(μ-CN)₂}₄]_n (2) and [Cd^II(edbea)₂][Au(CN)₂]₂·H₂O (3) were fully characterized by elemental, infrared, XRD (3), ESI-MS and thermal analysis. The DNA/BSA binding properties of these complexes were evaluated by spectrophotometric titration, fluorometric ethidium bromide kinetics, and DNA electrophoresis studies and their partially minor groove binding mode between the base pairs of DNA and electrostatic interaction between the amino acid residues of BSA were explained. The complexes were tested for their pharmacological properties. These molecules had excellent in vitro antiproliferative activity and also exhibited a strong tumor inhibiting effect against HT29, HeLa, C6 and Vero cell lines. These complexes had metastatic features as they are able to reduce cell migration activity and suppress tumor growth in vitro. Analysis of the DNA topoisomerase I relaxing activity indicates that the complexes do not inhibit topoisomerase I which regulates the topological states of the DNA double helix during DNA processing reactions. The TUNEL and DNA laddering assay results indicated that these compounds may destroy cell maintenance by triggering apoptosis. Immunohistochemistry staining analysis demonstrated that these complexes significantly decreased the expression of Bcl-2 in HeLa and HT29 cells while increasing the expression of P53 levels. Overall, the potent antiproliferative activity, low cytotoxic effect, good solubility, and micro molar range dosage observed for these complexes emphasizes their potential as anticancer drug candidates.     

Crystal and Molecular Structure of Potassium trans-bis(iminodiacetato)-cobaltate(III)-2H2O

The combination of iminodiacetic acid (H₂ida) with cobalt(II) chloride hexahydrate in the presence of sodium hydroxide, followed by heating, produces the trans-facial isomer of K[Co(ida)₂]·2H₂O. This compound contains extensive intermolecular and intramolecular coordination and hydrogen bonding involving the potassium ions, and results in a complex three-dimensional structure in which each potassium ion is immediately surrounded by six cobalt centers.     

Synthesis and crystal structures of [K(H<Subscript>2</Subscript>O)(Piv)]<Subscript>∞</Subscript> and [K<Subscript>2</Subscript>(Phen)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>(Piv)<Subscript>2</Subscript>]<Subscript>∞</Subscript>

A method for the synthesis of potassium pivalates (trimethylacetates) from potassium tert-butoxide and pivalic acid was proposed. The complexes of the formulas [K(H₂O)(Piv)]_∞(I) and [K₂(Phen)(H₂O)₂(Piv)₂]_∞ (II) (Piv denotes the pivalate anion and Phen denotes 1,10-phenanthroline) were obtained and characterized by elemental analysis and IR and ¹H NMR spectroscopy. The crystal structures of complexes I and II were determined using X-ray diffraction. Crystal structure I has a layered motif with two nonequivalent K atoms (C.N.s 5 + 2 and 6). The coordination of phenanthroline in II gives rise to a ribbon motif, the structure containing three nonequivalent K atoms (C.N.s 6, 6 + 1, and 8).     

EXAFS study of binuclear hydroxo-bridged copper(II) complexes

Extended X-ray absorption fine structure (EXAFS) measurements have been recorded at the K-edge of copper in binuclear monohydroxo-bridged copper(II) complexes [(bpy)₂Cu–OH–Cu(bpy)₂](ClO₄)₃ (1) and [(phen)₂Cu–OH–Cu(phen)₂](C1O₄)₃ (2) and dihydroxo-bridged copper(II) complexes [Cu₂(μ–OH)₂(bipy)₂]SO₄?·?5H₂O (3) and [Cu₂(μ–OH)₂(phen)₂]SO₄?·?5H₂O (4) (where bpy and phen are 2,2′-bipyridine and 1,10-phenanthroline, respectively) using the dispersive EXAFS beamline at 2?GeV Indus-2 synchrotron source at RRCAT, Indore, India. The EXAFS data have been analyzed using the software, Athena and Artemis. Theoretical models have been generated for 1 and 3 using available crystallographic data and then fitted to their experimental EXAFS data to obtain the structural parameters, which include bond-lengths, coordination numbers, and thermal disorders. The results obtained have been found to be comparable with their crystallographic results. As the crystallographic data for 2 and 4 are not available in the literature, we have determined their structural parameters by fitting their experimental EXAFS data with the same theoretical models which were generated for their corresponding analogous complexes 1 and 3, respectively. The structural parameters thus determined have been reported. Also, on the basis of the analysis of the EXAFS data, these four complexes have been shown to be binuclear, i.e. they contain two metals. Further, the values of the chemical shifts suggest that copper is in +2 oxidation state in these complexes.     

Conformational Studies of Dibenzo-30-crown-10 Complexes. Syntheses and Crystal Structures of Potassium and Ammonium Hexafluorophosphate Complexes

Abstract

Crown ether complexes formed by the dibenzo–30-crown–10 (DB30C10) with potassium and ammonium hexafluorophosphate have been prepared and their crystal structures have been determined by single crystal X-ray analyses. The potassium complex (compound 1) consists of [K(DB30C10)]⁺ cation and PF₆ ^? anion. Crystals are monoclinic, space group P2/n, with a = 11.9106(3), b = 9.8382(5), c = 14.3062(3) Å, β = 97.581(3)°, V = 1661.7(1) ų, D_c = 1.440 g cm^?3, Z = 4, R = 0.0675 for 2528 unique observed reflections. The potassium atom is coordinated to the ten oxygen atoms of the crown ligand at the distance from 2.859(3) to 2.930(3) Å. The ammonium complex (compound 2) has also 1:1 crown—cation ratio. Crystals are monoclinic, space group P2₁/n, with a = 12.5061(6), b = 19.3724(5), c = 14.2203(9) Å, β = 102.476(5)°, V = 3363.8(3) ų, D_c = 1.501 g cm^?3, Z = 4, R = 0.0677 for 4172 unique observed reflections. The ammonium cation is completely enclosed with crown oxygen atoms forming seven hydrogen bonds. The conformation of previously reported dibenzo-30-crown-10 complexes with potassium salts were investigated using polar coordinate maps.     

STRUCTURAL ANALYSES OF TWO MIXED CATIONIC LANTHANIDE POTASSIUM HEXACYANOFERRATE(II) TETRAHYDRATES

Abstract

The crystal structural investigations of 1 : 1 (La/Nd)KFe(CN)₆ 4H₂O (I) and 1:1 (Pr/Nd) KFe(CN)⁶·4H₂O (II) have been determined using three-dimensional, single-crystal, X-ray diffraction data and refined by least-squares to yield final reliability (R) factors of 0.0180 and 0.020 based on 358 and 343 unique reflections, respectively. I and II crystallize in the hexagonal space group P6₃/m (No. 176) with a = 7.371(1), c= 13.833(3)Å for I and a = 7.362(1), c= 13.799(3) A for II. For Z = 2, the respective calculated densities are 2.371 and 2.388 mgm^?3 [exp., 2.369(4) and 2.382(4)mgm^?3]. The coordination about the lanthanide central ions in both I and II is nine, and the geometric polyhedra are tricapped trigonal prisms (TTP). Cyanide bridging links the octahedral FeC₆ groups to the nine-coordinated (Ln/Nd)N₆(H₂O)₃ groups. The noncoordinated water molecule and the potassium ion occupy holes in the lattice along the three-fold axis above and below the lanthanide ions. Selected bond distances and angles are presented as well as discussions of the synthesis, TGA, IR, and digital SEM/EDS results, and other peripheral studies of I and II.     

Complexes of Co(II) and Zn(II) with N-(Thio)phosphorylthioureas AdNHC(S)NHP(O)(OiPr)2 and MeNHC(S)NHP(S)(OiPr)2

The reaction of the potassium salt of the N-(thio)phosphorylated thioureas AdNHC(S)NHP(O)(OiPr)₂ (HL^I , Ad = Adamantyl) and MeNHC(S)NHP(S)(OiPr)₂ (HL^II ) with Co(II) and Zn(II) in aqueous EtOH leads to [ML^I,II ₂] chelate complexes. They were investigated by UV-vis, ¹H and ³¹P NMR spectroscopy, and microanalysis. The molecular structures of [ML^I ₂] were elucidated by single crystal X-ray diffraction analysis. The metal centers in both complexes are found to be in a distorted-tetrahedral O₂S₂ environment formed by the C=S sulfur atoms and the P=O oxygen atoms of two deprotonated L^I ligands. The photoluminescence properties of [ZnL^II ₂] are also reported.     

Coordination interactions in the crystalline lattice of alkaline ions with the polyoxometalate [V12B18O60H6]10− ligand

In the present work, the synthesis and structural characterization of two new polyoxovanadoborate (BVO) frameworks, based on the [V₁₂B₁₈O₆₀H₆]^10? polyanion, are reported, K(H₃O)(enH₂)₄[V₁₂B₁₈O₆₀H₆]·9.60H₂O (1) and Li₈(NH₄)₂[V₁₂B₁₈O₆₀H₆]·8.02H₂O (2). Both compounds are obtained in a mixed valence ratio of 10V^IV/2V^V. Framework 1 is characterized by potassium ions coordinated by the BVO cluster and ethylenediammonium and hydronium ions as charge-compensating agents. In framework 2, the BVO clusters are coordinating lithium ions and the charge is compensated by ammonium ions. Using the SHAPE 2.1 program, it was possible to calculate the best geometry for the existing lithium and potassium ions. For 2, the lithium ions are five-coordinate, best described by a square pyramid (SPY-5), while the coordination sphere around the potassium ions in 1 are six-coordinate. For 1, the coordination sphere of the existing potassium ions in the framework can be described as trigonal prism (TPR-6). Calculations were also done for a previously reported cluster [Na₁₀[(H₂O)V₁₂B₁₈O₆₀H₆]·18H₂O] (3), in which the sodium ions are six-coordinate but in two different geometries, these being octahedral and TPR-6. The influence of the interactions of the alkali ions with the [V₁₂B₁₈O₆₀H₆]^10? polyanion, on the vanadate and borate absorption bands observed in the infrared spectra, is discussed.     

A 1-D ladder-like aggregate constructed from Preyssler anion and transition metal linkers

A 1-D ladder-like aggregate, K₂Na₆[Na(H₂O)Fe₂(H₂O)₈(P₅W₃₀O₁₁₀)] · 23.5H₂O (1; K₂Na₆[1a] · 23.5H₂O) has been obtained by conventional aqueous solution reaction. X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic system, space group P 2 ₁ /m, a = 16.938(3) Å, b = 21.396(4) Å, c = 17.520(4) Å, β = 98.14(3)°, V = 6285(2) ų, and Z = 2. Polyoxoanion 1a shows a 1-D ladder-like chain, built up of Preyssler anion and Fe³⁺ linkers, which represents the first extended structure based on Preyssler anion and transition metal linkers. The 1-D chains in 1 are further connected into a 3-D open framework by potassium and sodium cations. Compound 1 displays electrocatalytic activity towards the reduction of nitrite.     

Complexes of podand-containing bis(dithiophosphonate) ligands with cobalt(II), nickel(II) and cadmium(II): recognition of CH<Subscript>2</Subscript>Cl<Subscript>2</Subscript>

Reaction of the potassium salts of podand-containing bis(dithiophosphonate)s [PhO(4-C₆H₄)P(S)(SH)OCH₂CH₂]₂O (H ₂ L) with Co(II), Ni(II) and Cd(II) in aqueous EtOH leads to complexes of formulae M₂(L-S,S′)₂. The structural formulae of the compounds were deduced by physico-chemical and spectroscopic methods. It was established that complex Ni ₂ L ₂ recognizes CH₂Cl₂.     

Diorganotin(IV) complexes of 2-chloridophenylacetohydroxamic acid as prospective antimicrobials: synthesis,characterization, and biological properties

New diorganotin(IV) complexes [Me₂Sn(2-ClC₆H₄CH₂CONHO)₂] (1) and [n-Bu₂Sn(2-ClC₆H₄CH₂CONHO)₂] (2) have been synthesized by reactions of Me₂SnCl₂ and n-Bu₂SnCl₂ with potassium 2-chloridophenylacetohydroxamate (2-ClPhAHK = 2-ClC₆H₄CH₂CONHOK) in 1:2 molar ratio in MeOH+C₆H₆ solvent medium and characterized by elemental analyses, molar conductivity, molecular weight determinations and spectroscopic techniques (IR, ¹H, ¹³C, and ¹¹⁹Sn NMR) and mass spectrometry. Bonding through carbonyl and hydroxamic oxygens (O,O coordination) and distorted-octahedral geometry around tin is proposed. The electrochemical behavior of 1 and 2 studied by cyclic voltammetry shows quasi-reversible reductions. Thermal behavior of 1 and 2 in N₂ shows decomposition in one step affording SnO as the residue. The in vitro antimicrobial activity assay against pathogenic Gram-negative bacteria viz. Salmonella typhi, Escherichia coli; Gram-positive Bacillus cereus and Staphylococcus aureus and fungi Aspergillus niger and Alternaria alternata by MIC method revealed their significant antimicrobial potential relative to the respective standard Chloramphenicol and Nystatin drugs.