Coordination chemistry of anticrowns. An unusual complex of perfluorinated three-mercury anticrown (o-C6F4Hg)3 with p-bromotoluene and 1,2-dichloroethane

Russian Chemical Bulletin -     

Coordination chemistry of anticrowns. Complexation of cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 with compounds containing an active methylene group

The reactions of three-mercury anticrown (o-C₆F₄Hg)₃ (1) with acetoacetic ester (AE), malonic ester (ME), and malonodinitrile (MN) afford 1: 1 complexes {[(o-C₆F₄Hg)₃](AE)} (3), {[(o-C₆F₄Hg)₃](ME)} (4), and {[(o-C₆F₄Hg)₃](MN)} (5). The structures of complexes 3–5 were determined by X-ray diffraction analysis. Complex 3 has a discrete structure in the solid state, whereas complexes 4 and 5 form in the crystal extended stacks representing polydecker sandwiches with alternating molecules of 1 and ME or MN. According to the X-ray diffraction and IR spectral data, the molecule of AE in complex 3 is in the keto form.     

Synthesis, crystalline and molecular structure of palladium(II) binuclear complex with cysteine

The new palladium(II) binuclear complex [Pd₂(μ-S-Cys)(μ-S-CysH)(dipy)₂](NO₃)₃ with bridging L-cysteine and L-cysteinate anion was synthesized and investigated by the methods of X-ray crystal analysis, IR spectroscopy, and elemental analysis.     

Synthesis and molecular structure of the polar,binuclear complex,monochlorotetra-(6-fluoro-2-oxopyridine)diruthenium(II,III)

The dark purple title compound was prepared by reaction of Ru₂Cl(O₂CCH₃)₄ with molten 6-fluoro-2-hydroxypyrine (Hfhp) in quantitative yield. Crystals of composition Ru₂Cl(fhp)₄ were obtained by slow diffusion of hexane into a CH₂Cl₂ solution of the compound. The crystals belong to the tetragonal space group I4mm with the following unit-cell dimensions: a = b = 10.890(2) Å, c = 13.178(4) Å, α = β = γ = 90.0°, V = 1562.8(6) ų, and Z = 2. The Ru₂Cl(fhp)₄ molecule, which has crystallographic 4mm (C_4c) symmetry, contains a diruthenium(II,III) unit with a metalmetal bond order of 2.5. The four bridging fhp ligands across the Ru₂ unit are oriented in one direction to form a polar molecule. The coordinatioin spheres of the two ruthenium atoms [Ru(1) and Ru(2)] are Ru(2)N(I)₄ and Ru(1)Cl(1)O(1)₄, respectively. The axial site on Ru(1) is blocked by four F(1) atoms. The Ru(1)Ru(2), Ru(2)Cl(1), Ru(2)O(1) and Ru(1)N(1) distances are 2.284(1), 2.427(3), 1.971(2) and 2.089(4) Å, respectively. The electronic spectrum of the compound in CH₂Cl₂ shows two strong bands at 552 nm (ε = 4720 M⁻¹ cm⁻¹) and 355 nm ε = 3770 M⁻¹ cm⁻¹). Cyclic voltammetry of Ru₂Cl(fhp)₄ in CH₂Cl₂ in the presence of 0.1 M [N(C₂H₅)₄]ClO₄ at 100 mV s⁻¹ shows two quasireversible metal-centered one-electron oxication and reduction processes at +1.68 (ΔE_p = 120 mV) and −0.01 V (ΔE_p = 126 mV), respectively, vs an AgAgCl reference electrode.     

Synthesis of polyalkylenearyls Communication 2. Polycondensation of 1,2-dichloroethane with diarylalkanes

Summary A study was made of the poly condensation of 1,2-dichloroethane with bibenzyl. It was shown that 1,2-dichloroethane polycondenses with biphenyl, but not with diphenylmethane.     

Synthesis,crystal structure and magnetic property of a binuclear iron(III) citrate complex

The compound (Hql)₂[Fe₂(cit)₂(H₂O)₂]·4H₂O (1) [ql = quinoline, cit^4– = C(O^–)(CO^– ₂)(CH₂CO^– ₂)₂], prepared by reacting ferric nitrate, sodium citrate and quinoline in a molar ratio of 1:1:1 in aqueous solution, was characterized by density measurements, elementary analysis, i.r., X-ray crystallography and magnetic measurements. The X-ray crystallography results reveal that the molecule (1) consists of a binuclear iron(III) citrate anionic complex [Fe₂(cit)₂(H₂O)₂]^2– and two protonated quinolines [Hql]⁺. The anionic complex has a centro-symmetric structure, in which two Fe³⁺ ions are bridged by two ₂-alkoxo groups of the two deprotonated citrate ligands. The other coordination sites of the two slightly distorted octahedra are completed by all the carboxylate groups of the two cit^4– ligands in a monodentate mode, and two coordinated water molecules. Magnetic measurements indicate that the two Fe³⁺ ions are antiferromagnetically coupled below 200 K. A least-squares fit of variable-temperature (1.5–291 K) molar susceptibility data to a dimer model gave the coupling constant J/k = –6.35(7) K and Landé factor g = 2.052(9), where the spin-only Heisenberg–Dirac–van Vleck Hamiltonian is expressed as H = –2J S ₁ S ₂.     

Synthesis and structure of binuclear iron(ii) complex with the cage-like ligand as a model of methane monooxygenase

A binuclear iron(II) complex, [Fe^II ₂L(OTf)₂](OTf) (1), with the cage-like ligand LH = [(PyCH₂)₂N(CH₂)₃O]₂C₆H₃COOH containing an immobilized carboxylate was synthe-sized and characterized in order to model an active center of soluble methane monooxygenase (sMMO). Studies on the oxidation of cyclohexane with hydrogen peroxide or O₂ involving this complex showed that the complex 1 does not catalyze the indicated reactions. Consideration of crystal structure of complex 1 gives an explanation of its inactivity in the reaction of O₂ activation.     

Synthesis and structure of a binuclear ruthenium 4-chlorobenzamidato complex

The compound Ru₂Cl(4-Cl-C₆H₄CONH)₄ was prepared by reaction of Ru₂Cl(O₂CCH₃)₄ with 4-Cl-C₆H₄CONH₂ at 180°C. Crystals of the composition Ru₂Cl(4-Cl-C₆H₄CONH)₄CH₃OH were obtained by slow diffusion of CH₃OH containing Et₄NCl into a Me₂SO solution of the compound. The structure of the crystalline product, which loses solvent of crystallization on removal from the mother liquor, was solved by X-ray crystallography by mounting a single crystal in a capillary containing the mother liquor. The crystals belong to the space group P1? (triclinic crystal system) with a = 12.731(3) Å, b = 14.389(3) Å, c = 12.604(3) Å, α = 103.41(2)°, β = 106.43(2)°, γ = 64.90(2)°, V = 1988.6(8) ų and Z = 2. There are two half ruthenium dimers linked by a Cl atom and an uncoordinated solvent CH₃OH molecule per asymmetric unit. The ruthenium dimers lie on two centers of inversion at 0, 0, 0 and 1/2, 0, 0. The chloride ions bridge dinuclear cations in the crystal, forming infinite zigzag chains. The average Ru-Ru distance is 2.296[1] Å and each ruthenium atom has a RuClN₂O₂ coordination sphere where the average Ru′-Ru-Cl angle is virtually linear (175.68[6]°). The metal oxidation states in the complex are + 2 and + 3, giving an average value of + 2.5. The arrangement of four bridging 4-Cl-benzamidato ligands is of the 2 : 2 type. The average Ru-N, Ru-O, Ru-Cl distances and Ru(1)-Cl(1)-Ru(2) angle are 2.036[6] Å, 2.044[5] Å, 2.583[2] Å and 117.26(8)°, respectively. The IR spectrum of the compound shows two N-H stretches at 3380 and 3340 cm^?1. The electronic spectrum of the compound in Me₂SO exhibits bands at 558 nm (ε = 340 M^?1 cm^?1), 425 nm (1000) and 320 nm (22,700).     

Crystal structure of a binuclear polymeric self-assembled lead(II) complex.

A polymeric self-assembled complex [[Pb(pydc)(pydc-H2)(H2O)2]2]n is prepared from the complexation of a novel pyridine containing self-assembling system, LH2, [pyda-H2]2+[pydc]2- (pyda = 2,6-pyridindiamine and pydc-H2 = 2,6-pyridinedicarboxilic acid) and lead(II) nitrate in 84% yield. The characterization was performed using X-ray crystallography. The crystal system is triclinic with space group P1 and two molecules per unit cell. The unit cell dimensions are a = 6.913(2) A, b = 10.687(4) A and c = 11.182(4) A with alpha = 92.805(6) degrees, beta = 101.821(6) degrees and gamma = 95.688(6) degrees. The final R value is 0.0373 for 4633 reflections measured. This compound is a nine-coordinate binuclear complex with two metal fragments linked via the central four-membered Pb2O2 ring. The crystal also contains a neutral [pydc-H2] molecule, that form hydrogen and coordination bonds that dominate the crystal packing, by forming layers of molecules.     

Synthesis of substituted 1,2-di(alkylsulfonyl)indolizines. Molecular and crystal structure of 3-(4-fluorobenzoyl)-6-methyl-1,2-di(propylsulfonyl)indolizine

The reactions of substituted pyridinium salts with E-1,2-di(alkylsulfonyl)-1,2-dichloroethenes proceed regiospecifically. Heating of these reagents in chloroform in the presence of a threefold excess of Et₃N affords substituted 1,2-di(alkylsulfonyl)indolizines in high yields. The structures of the reaction products were confirmed by physicochemical methods, including X-ray diffraction. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1205–1209, May, 2005.     

Synthesis and structure of the 1,2-isopropylidene-α-D-glucofuranose 3,5,6-bis-cyclophosphite complex with tungsten(0) pentacarbonyl

Metallocomplexes with optically active ligands are of considerable interest as catalysts of stereoselective processes. A complex of 1,2-isopropylidene-α-D-glucofuranose 3,5,6-bis-cyclophosphite with tungsten(0) pentacarbonyl has been synthesized for the first time and studied by X-ray crystallography.     

Synthesis,crystal structure and magnetic properties of N -benzesulfonyl-L-glutamic acid-bridged binuclear nickel(II) complex

N-benzesulfonyl-L-glutamic acid-bridged binuclear nickel(II) complex, [Ni₂(Bs-Glu)₂(bipy)₂ (H₂O)₂]?·?3H₂O (Bs-Glu?=?N-benzesulfonyl-L-glutamic acid dianion, bipy?=?2,2′-bipyridine), has been synthesized and characterized structurally and magnetically. It crystallizes in the triclinic space group P 1. The α-carboxyl group coordinates to Ni(II) in a monodentate mode, while the γ-carboxyl group coordinates in a chelating mode. In the temperature range 2–300?K, magnetic measurements show that the exchange interaction of the two Ni(II) ions is antiferromagnetic, and the values for J, g are ?2.47?cm^?1 and 2.18, respectively.     

Synthesis,crystal structure and magnetic properties of a new macrocyclic binuclear copper(II) complex

A new binuclear copper complex [CuLCl₂]₂, [L = 1-(p-tolylsulfonyl)-1,4,7- triazacyclononane], has been synthesized and structured as well as magnetically characterized. In the complex, each copper(II) atom is located in the center of a distorted square pyramidal configuration of five coordinating atoms (two nitrogen atom and three chlorine atom). Two copper(II) atoms were bridged by two chlorine anions (Cl1 and Cl1a). The distance between two copper(II) atoms is 3.483 Å. An antiferromagnetic exchange coupling effect exists in the complex.     

Microwave-assisted α-halogenation of 2-methylquinolines with tetrabutylammonium iodide and 1,2-dichloroethane (1,2-dibromoethane)

A simple and efficient methodology permitting the halogenation of 2-methylquinolines into 2-(chloromethyl)quinolines or 2-(bromomethyl)quinolines in the tetrabutylammonium iodide and 1,2-dichloroethane (1,2-dibromoethane) system has been developed for the first time. The halogenation can be rapidly completed with good to excellent yields and high selectivity under microwave irradiation.     

Macrometallocycle binuclear NHC silver(I) complex with bridging azobenzene: Synthesis,structure and recognition for hydrogen sulfate

One bis-imidazolium salt 2,2′-di[2’’-(N-methyl-imidazoliumyl)ethoxyl]azobenzene hexafluorophosphate (LH₂·(PF₆)₂) and its macrometallocycle binuclear N-heterocyclic carbene silver(I) complex [(LAg)₂](PF₆)₂ were prepared and characterized. The structure of [(LAg)₂](PF₆)₂ was determined by X-ray single crystal diffraction, ¹H NMR and ¹³C NMR spectroscopy. In complex [(LAg)₂](PF₆)₂, one 34-membered macrometallocycle was formed by two biscarbene ligand L and two silver(I) ions. Additionally, the selective recognition of hydrogen sulfate using [(LAg)₂](PF₆)₂ as a chemosensor was investigated on the basis of fluorescence titrations, ultraviolet titrations, ¹H NMR titrations, HRMS and IR spectra. Complex [(LAg)₂](PF₆)₂ was demonstrated to be an effective chemosensor for hydrogen sulfate.     

Synthesis,crystal structure,and DNA binding of a new oxalato-bridged binuclear zinc(II) complex

A new binuclear zinc(II) complex bridged by μ-oxalate, and end-capped with 2,2′-bipyridine (bpy), [Zn₂(ox)(bpy)₄](ClO₄)₂ · H₂O, has been synthesized and characterized by elemental analyses, molar conductance, IR, and electronic spectra and single-crystal X-ray diffraction. The single-crystal X-ray analysis reveals that the [Zn₂(ox)(bpy)₄]²⁺ cation has two zinc(II) centers bridged by a planar bis(bidentate) oxalate group with Zn···Zn distance of 5.482(3) Å; each zinc(II) is in a distorted octahedral environment. The crystal structure is stabilized by non-classical C–H···O hydrogen bonds and π–π stacking interactions to form a 3-D supramolecular structure. The interaction of the complex with calf-thymus DNA (CT-DNA) was explored by using electronic and fluorescence spectra and viscosity measurements. The results reveal that the complex intercalates with CT-DNA with intrinsic binding constant of 4.1 × 10⁴ M^?1.     

Synthesis, structure and characterization of binuclear silver(I) complexes

Summary Two binuclear Ag^I complexes, [{Ag(dppp)}₂](NO₃)₂ (1) and [{Ag(dppb)}₂(NO₃)]₂ (2) (dppp = Ph₂P(CH₂)₃PPh₂, dppb = Ph₂P(CH₂)₄PPh₂], were synthesized and characterized by elemental analysis, t.g., i.r. and ³¹P-n.m.r. spectra. Single crystals of complex (2) were obtained from MeOH-CHCl₃. The X-ray crystal structure shows that the dppb ligand is bidentate, with two ligands bridging two metal ions to form a centrosymmetric dimer.     

Synthesis,structure and characterization of binuclear copper(I) complexes

Binuclear copper(I) complexes [Cu(dppm)(NO3)]2 (1), dppm=Ph2PCH2PPh2, [Cu(dppm)(2,9-Me2Phen)]2(NO3)2 (2), [Cu(dppm)(I)]2 (3) and [Cu(dppm)(py)]2(NO3)2 (4), (py=pyridine) have been synthesized by ligand reduction of cupric nitrate with dppm in EtOH and characterized by elemental analyses, molecular weight determination, t.g.a., 31P-n.m.r spectra; their electronic conductivities and c.v. waves have also been measured. The results show that dppm coordinates as a bridging bidentate ligand to the CuI atoms, and that NO3 behaves as a monodentate ligand or free ion in the newly prepared complexes.     

Coordination chemistry of mercury-containing anticrowns. Synthesis and structures of the complexes of cyclic trimeric perfluoro-o-phenylenemercury with ethanol, THF and bis-2,2′-tetrahydrofuryl peroxide

Cyclic trimeric perfluoro-o-phenylenemercury (o-C₆F₄Hg)₃ (1) is capable of reacting with ethanol to form a 1:1 complex, {[(o-C₆F₄Hg)₃](EtOH)} (2), having a pyramidal structure. The ethanol molecule in 2 is coordinated through the oxygen atom to all Hg atoms of the macrocycle. The interaction of 1 with THF followed by drying of the product obtained in vacuum also gives the corresponding pyramidal 1:1 complex {[(o-C₆F₄Hg)₃](THF)} (3). However, when a THF solution of 1 is slowly concentrated to a small volume and the resulting crystals are not dried, three cocrystallized adducts, viz., {[(o-C₆F₄Hg)₃](THF)₂} (4), {[(o-C₆F₄Hg)₃](THF)₃} (5) and {[(o-C₆F₄Hg)₃](THF)₄} (6), containing two, three and even four THF molecules, respectively, are produced. Complex 4 has a bipyramidal structure. Complexes 5 and 6 are also characterized by the presence of a bipyramidal fragment formed by two coordinated THF species. The topological analysis of the DFT-calculated function of the electron density distribution in the crystals of 2 and 3 revealed the critical points (3, −1) on each of the three Hg···O lines, which is in accord with the X-ray diffraction data indicating on the presence of the triply coordinated Lewis base molecule in both adducts. If a THF solution of 1 is held for a month at 20 °C on air under stirring, a sandwich complex of 1 with previously unknown bis-2,2′-tetrahydrofuryl peroxide (THFPO) is formed. The THFPO ligand in this sandwich, {[(o-C₆F₄Hg)₃]₂(THFPO)} (7), provides all its four oxygen atoms for the bonding to the molecules of 1. Two of these oxygen atoms, belonging to the tetrahydrofuryl moieties, are cooperatively bound each by three Hg atoms of the neighbouring macrocyclic unit whereas two others, belonging to the peroxide group, coordinate to a single Hg atom of the adjacent macrocycle.