(Mesitylene)ruthenium π-complexes with benzo-15-crown-5 and dibenzo-18-crown-6

The reactions of benzo-15-crown-5 and dibenzo-18-crown-6 with 1 equiv. of [(mes)Ru(MeNO₂)₃]²⁺ (mes = 1,3,5-C₆H₃Me₃) give the mononuclear complexes [(mes)Ru(η⁶-benzo-15-crown-5)]²⁺ (1) and [(mes)Ru(η⁶-dibenzo-18-crown-6)]²⁺ (2) in 50% yield. Similar reaction with 2 equiv. of [(mes)Ru(MeNO₂)₃]²⁺ produces the dinuclear complex [(μ-η⁶:η⁶-dibenzo-18-crown-6)Ru₂(mes)₂]⁴⁺ (3) in 96% yield as a 2:3 mixture of cis- and trans-isomers. Structures of 2(OTf)₂ and trans-3(OTf)₄ were confirmed by X-ray diffraction. The NMR titration showed that mononuclear dications 1 and 2 bind Na⁺ ion less effective (K_a = 600 and 250 M^-1) than free benzo-15-crown-5 and dibenzo-18-crown-6 (K_a = 2 × 10⁵ and 5 × 10⁶ M⁻¹). The dinuclear tetracation 3 does not bind Na⁺ within measurable limits of NMR titration method. The electrochemical behaviour of complexes 1-3 was studied in propylene carbonate solution. They exhibit a partially chemically reversible Ru(II)/Ru(I) reduction, which in the case of the dinuclear complex 3 proceeds through two slightly separated steps. The redox activity of the complexes is substantially unaffected by the presence of sodium ion.     

Coordination-driven self-assembly of dibenzo-18-crown-6 functionalized Pt(Ⅱ) metallacycles

Coordination-driven self-assembly was used to construct two metallacycles of a dicarboxylatefunctionalized dibenzo-18-crown-6 in combination with either a 0° anthracene-based clip-type acceptor or a 60° phenanthrene-based acceptor. The angularities of these moieties make them suitable for the formation of a [2 + 2] rectangle and a [3 + 3] triangle, respectively. The synthesis, characterization and host-guest chemistry of two metallacycles were described and supported by³¹P{¹     

Chromatographic separation of cerium(Ⅲ) in L-valine medium using poly[dibenzo-18-crown-6]

A column chromatographic method has been developed for the separation and determination of cerium(Ⅲ) using poly[dibenzo-18-crown-6]. The separation was carried out in L-valine medium. The adsorption of cerium(Ⅲ) was quantitative from 1×10-1 to 1×10-4 mol/L L-valine. Amongst the various eluents, 1.0-8.0 mol/L hydrochloric acid, 1.0-8.0 mol/L hydrobromic acid, 1.0-8.0 mol/L perchloric acid, 1.0-2.0 mol/L sulfuric acid and 4.0-5.0 mol/L acetic acid, were found to be the efficient eluents for cerium(Ⅲ). The capacity of poly[dibenzo-18-crown-6] for cerium(Ⅲ) was (0.428±0.01) mmol/g. The method was applied to the separation of cerium(Ⅲ) from associated elements link uranium(Ⅵ) and thorium(Ⅳ). It was also applied for the determination of cerium(Ⅲ) in geological samples. The method is simple, rapid and selective with good reproducibility (approximately±2% ).     

Syntheses and crystal structures of (18-crown-6)bis(perchlorato-O,O′)strontium and (18-crown-6)bis(perchlorato-O,O′)barium

Two complexes, namely, (18-crown-6)bis(perchlorato-O,O′)strontium (I) and (18-crown-6)bis(perchlorato-O,O′)barium (II), are synthesized. Their crystal structures are determined by X-ray diffraction analysis. The structures of I (space group P2₁/c, a = 15.266 Å, b = 11.080 Å, c = 13.235 Å, β = 109.20°, Z = 4) and II (space group P2₁/n, a = 8.330 Å, b = 11.202 Å, c = 11.752 Å, β = 98.38°, Z = 2) are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.077 (I) and 0.041 (II) against 3714 (I) and 2478 (II) independent reflections (CAD-4 diffractometer, λMoK _α radiation). Complex molecules [Sr(18C6)(ClO₄)₂] in the structure of I and [Ba(18C6)(ClO₄)₂] in II (in the inversion center)—are of the host-guest type. The Sr²⁺ or Ba²⁺ cation is localized in the center of a cavity of the 18-crown-6 ligand and coordinated by its all six O atoms. In compounds I and II, the coordination polyhedron of the Sr²⁺ and Ba²⁺ cations (coordination number 10) can be described as a distorted hexagonal bipyramid with two bifurcated vertices at two O atoms of two ClO ₄ ^? ligands, which are disordered in I and II and each of them has two orientations.     

Some reactions of dimethyl tin bis-S,S′ -(O-sodium thiosulfate) and the structure of its complex with dibenzo-18-crown-6

The reactions of the title compound, Me₂Sn(S-SO₃Na · H₂O)₂, with alkyliodides and trimethyltin chloride in an aqueous medium, as well as with dibenzo-18-crown-6 (DB-18-C-6) in acetone have been studied. The iodides RI (R = Me, Et) attack both of the tin—sulfur bonds to give dimethyltin diiodide and the respective disulfides, R₂S₂. Trimethyltin chloride enters an exchange reaction which involves sodium ions and affords Me₂Sn(S-SO₃SnMe₃)₂ as the reaction intermediate; the latter decomposes to ultimately give trimethyltin sulfate, dimethyltin thiosulfite, and elemental sulfur. An ionic complex, [Me₂Sn(S-SO₃)₂]₂ ^2–[Na(DB-18-C-6)(Me₂CO)]⁺[Na(DB-18-C-6)(Me₂CO)(H₂O)]⁺, soluble in acetone and methylene chloride has been also synthesized, and its structure has been determined by means of X-ray techniques.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 962–966, May, 1993.     

Preparation and crystal structure of bis[(dibenzo-18-crown-6)potassium]bis(μ<Subscript>2</Subscript>-chloro)-tetrachlorodicuprate(II)

A new complex compound bis[(dibenzo-18-crown-6)potassium]bis(μ₂-chloro)-tetrachlorodicuprate( II), {[K(Db18c6)]₂Cu₂Cl₆} (I) was prepared and its crystal structure was investigated by XRD analysis. Complex molecule I consist of anion [Cu₂Cl₆]²⁻ located in a crystallographic center of inversion, and two centrosymmetrical to each other complex cations [K(Db18c6)]⁺ of “guest-host” type: the cation K⁺ is located in the cavity of the crown-ligand Db18c6 and is coordinated by all its six O atoms, and also by one Cl atom of anion [Cu₂Cl₆]²⁻. The coordination of this cation K⁺ is enlarged up to hexagonal-bipyramidal due to the formation of unusual coordination bond K⁺ → π(      

Systematic study of the transfer of amino acids across the water/1,2-dichloroethane interface facilitated by dibenzo-18-crown-6

Facilitated ion transfer reactions of 20 amino acids with dibenzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically using cyclic voltammetry. It was found that there were only 10 amino acids, that is, Leu, Val, lie, Phe, Trp, Met, Ala, Gly, Cys, Gin (in brief), whose protonated forms as cations can give well-defined facilitated ion transfer voltammograms within the potential window, and the reaction pathway was proven to be consistent with the transfer by interfacial complexation/dissociation (TIC/TID) mechanisms. The association constants of DB 18C6 with different amino acids in the DCE (β0), and the kinetic parameters of reaction were evaluated based on the steady-state voltammetry of micro- or nano-pipets, respectively. The experimental results demonstrated that the selectivity of complexation of protonated amino acid by DB18C6 compared with that of alkali metal cations was low, which can be attribu     

Synthesis and crystal structure of octaaqua(di-μ-bromo)dimanganese(II) dibromide 18-crown-6

A new crystalline complex octaaqua(di-μ-bromo)dimanganese(II) dibromide 18-crown-6, [Mn₂Br₂(H₂O)₈]Br₂ · 18C6, is synthesized and studied by X-ray diffraction analysis. The crystals of compound I are triclinic, space group $P\bar 1$ , a = 9.093 Å, b = 9.683, Å, c = 10.032 Å, α = 111.35°, β = 116.23°, γ = 92.64°, Z = 1. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.028 for 3276 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). The [Mn₂Br₂(H₂O)₈]²⁺ complex cation lying at the inversion center is binuclear with two bridging Br atoms and eight water molecules. The coordination polyhedron of one Mn²⁺ cation is a distorted cis-octahedron with two Br atoms and four O atoms of the water molecules at its corners. The centrosymmetric 18C6 molecule has an usual conformation. A crystal of compound I contains a developed three-dimensional network of intermolecular (interionic) hydrogen bonds.     

Crystal Structure of [La(NCS)_3(18-crown-6)(DMF)]

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ[Ｌａ（ＮＣＳ）_３（１８－ｃｒｏｗｎ－６）（ＤＭＦ）]ＭａｏＪｉａｎｇ－Ｇａｏ（ＦｕｊｉａｎＩｎｓｔｉｔｕｔｅｏｆＲｅｓｅａｒｃｈｏｎｔｈｅＳｔｒｕｃｔｕｒｅｏｆＭａｔｔｅｒ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｆｕｚｈ?..     

133Cs NMR Study of Cs+ Ion Complexes with?Aza-18-crown-6, Diaza-18-crown-6 and?Dibenzyldiaza-18-crown-6 in Binary Acetonitrile?CNitromethane Mixtures

Cesium-133 nuclear magnetic resonance spectroscopy was used as a sensitive probe to investigate the stoichiometry and stability of Cs⁺ ion complexes with aza-18-crown-6 (A18C6), diaza-18-crown-6 (DA18C6) and dibenzylediaza-18-crown-6 (DBzDA18C6) in different binary acetonitrile?Cnitromethane mixtures. In all cases, the exchange between free and complexed cesium ion was fast on the NMR time scale and only a single population average resonance was observed. The ¹³³Cs chemical shift?Cmole ratio data indicated that the cesium ion forms 1:1 cation?Cligand complexes with the investigated aza-crowns in all acetonitrile?Cnitromethane mixtures. The formation constants of the resulting complexes were evaluated from computer fitting of the chemical shift?Cmole ratio data. The stability of the resulting 1:1 complexes with Cs⁺ were found to vary in the order A18C6 > DBzDA18C6 > DA18C6. In all cases, there is the inverse relationship between the complex stability constants and the amount of acetonitrile in the mixed solvent.     

Enthalpy parameters for interaction of small peptides with 18-crown-6 and aza-18-crown-6 in water at 25°C

Enthalpies of dilution have been determined for binary aqueous solutions of 1-aza-18-crown-6 as well as for ternary aqueous solutions containing glycine, glycylglycine, glycyl-L--alanine, L--alanyl-glycine, L--alanyl-L--alanine, DL--alanyl-DL--alanine, trialanine and 18-crown-6 and/or 1-aza-18-crown-6 and or 1,10-diaza-18-crown-6 at 25°C. The results have been treated by the McMillan-Mayer approach in order to obtain enthalpic virial coefficients for homotactic and heterotactic interactions. A significant exo-effect is demonstrated by the enthalpically favorable interaction between peptides and the 18-crown-6. The additivity of the positive alanyl group contribution toh _xy has been confirmed on the basis of oligomeric data. The influence on the enthalpy of the 18-crown-6-peptide interaction of the methyl group position, in relation to the ammonium group in peptides, has been found to result in the exo-effect decreasing with a decrease of this distance. Some decrease in enthalpy of L--alanyl-L--alanine and DL--alanyl-DL--alanine by 18-crown-6 has been observed as well.Deceased.     

Synthesis and crystal structure of aquabis(isothiocyanato)(18-crown-6)lead(II)(isothiocyanato)-(18-crown-6)(nitrato-<Emphasis Type="Italic">O,O</Emphasis>′)lead(II)

A new mixed complex compound, aquabis(isothiocyanato)(18-crown-6)lead(II)(isothiocyanato)-(18-crown-6)(nitrato-O,O′)lead(II) [Pb(NCS)₂(18-crown-6)(H₂O)][Pb(NCS)(NO₃)(18-crown-6)] is prepared, and its crystal structure is studied by XRD analysis. The structure was solved by the direct method and was refined by full-matrix least-squares method in anisotropic approximation to R = 0.044 for all 3648 measured independent reflexes (automatic diffractometr CAD-4, λMoK _α). This crystal structure contains two symmetrically independent halves of the two individual and differing in type complex “guest-host” molecules. One of them (with the H₂O ligand molecule) is located on the crystallographic axis 2, and the other is located around the crystallographic inversion center and is statistically disordered relative to this center (except for its crown-ligand).     

Synthesis and crystal structure of bis[(18-crown-6)potassium] bis(μ2-bromo)tetrabromodicopper(II)

A new complex bis[(18-crown-6)potassium] bis(μ₂-bromo)tetrabromodicopper(II), [{K(18-crown-6)}₂Cu₂Br₆] (I), is synthesized and studied by X-ray diffraction analysis (space group P2₁/n, a = 9.137 Å, b = 34.860 Å, c = 13.414 Å, β = 99.53°, Z = 4). The structure is solved by a direct method and refined by the fullmatrix least-squares method in the anisotropic approximation to R = 0.083 for 5850 independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). Complex molecule I consists of the central binuclear anion [Cu₂Br₆]^2? and two peripheral cations K(18-crown-6)]⁺ of the host-guest type bound to the [Cu₂Br₆]^2? anion through two and one K-Br coordination bonds. In the [Cu₂Br₆]^2? anion, the coordination polyhedra of two Cu atoms can be described as strongly flattened tetrahedra. In two [K(18-crown-6)]⁺ fragments, the coordination polyhedra of their K⁺ cations (coordination numbers 8 and 7) are distorted hexagonal pyramids with a base of six O atoms of the 18-crown-6 ligand and a bifurcated or ordinary vertex: the Br atoms of the [Cu₂Br₆]^2? anion. Two 18-crown-6 ligands have a standard crown conformation.     

New Cluster Complexes with Octahedral Cores of Niobium Atoms: Syntheses, Structures, and Properties of [K(18-crown-6)]2[K(18-crown-6)(H2O)2]2[Nb6Cl12(CN)6] · 2CH3CN and [(C6H5)4P]4[Nb6Cl12(NCS)6] · 0.94CH3OH

The syntheses and structures of [K(18-crown-6)]₂[K(18-crown-6)(H₂O)₂]₂[Nb₆Cl₁₂(CN)₆] · 2CH₃CN (1) and [(C₆H₅)₄P]₄[Nb₆Cl₁₂(NCS)₆] · 0.94CH₃OH (2), determined by X-ray single crystal diffraction, are reported. Crystal data: [K(18-crown-6)]₂[K(18-crown-6)(H₂O)₂]₂[Nb₆Cl₁₂(CN)₆] · 2CH₃CN: monoclinic, P2₁/n, a = 17.8240(9), b = 15.9395(8), c = 18.660(1) Å, β = 113.833(2)°, Z = 2; [(C₆H₅)₄P]₄[Nb₆Cl₁₂(NCS)₆] · 0.94CH₃OH: triclinic, $ P\bar{1} $ , a = 14.6239(3), b = 14.6237(5), c = 15.9831(3) Å, α = 113.482(1)°, β = 114.684(1)°, γ = 92.585(1)°, Z = 1. Both complexes contain [Nb₆Cl₁₂ Y ₆]^4? cluster anions with Y = CN and NCS, respectively, on all six cluster exo-positions. They have been prepared via ligand substitution in solution, starting from K₄[Nb₆Cl₁₈], which was synthesized by a high temperature solid state reaction. Structural trends and spectroscopic properties are discussed and compared to related compounds reported previously in the literature.     

One-dimensional Chain Dibenzo-18-crown-6 Complex: [K(DB18-C-6)]2[Pt(SCN)6]·2H2O·C2H4Cl2 Assembled by Cation-π Interactions

Introduction Cation-πinteractions have come to be appreciated as an important noncovalent binding force in many areas of modern chemistry, such as material design, molecular biology, host-guest and supramolecular chemistry[1-3].     

[｛Pt_4(en)_4(NHCO~tBu)_4｝｛Tl(18-crown-6)｝_2](PF_6)_6的合成与晶体结构(英文)

The metallophilic attraction between closed shellor pseudo closed shell metal atoms with the configura-tion of d10,s2,d8has received considerable attentionrecently mainly because such metal-metal interactionsare closely associated with many important chemicaland physical properties such as catalysis,electronicconductivity and luminescence[1].The d8-d10-s2closed-shell metallophilic interactions and ligand functionali-ty have resulted in the formation and isolation ofmultinuclear aggregates with …     

Conductance Study of the Binding of K+ by Dibenzo-pyridino-18-crown-6 and 1,10-N,N′-didecyl-diaza-18-crown-6 in Acetonitrile

The binding of K+ by dibenzo-pyridino-18-crown-6 (B2-py-18-C-6) and1,10-N,N-didecyl-diaza-18-crown-6 (22-DD) has been studiedconductometrically at 10, 15, 20 and 25 °C in acetonitrile. Thecomplexes formed were assumed to have 1 : 1 stoichiometry. The complexes ofK+ with 18-crown-6 (18-C-6) and dibenzo-18-crown-6 (B2-18-C-6) were alsostudied for comparison purposes. The stability constant, K, of a givencomplex and its molar conductance, c, were obtained by subjectingthe conductance data to a non-linear least-squares curve fitting procedure.The values of the enthalpy change, H, the entropy change, Sand the Gibbs free energy, G, associated with the formation of the 1: 1 complexes were derived and compared with relevant literature data. Thevalues of G at 25 °C indicate that the binding capacity of thefour macrocycles follows the order 18-C-6 > 22-DD > B2-18-C-6 >B2-py-18-C-6. The difference between the molar ionic conductance of the freeK+ cation and that of the bound cation, KL+, was estimated and the trend insuch differences correlates with the molecular size of the macrocycle, L.