Diaquabromo(18-crown-6)rubidium and triaqua(18-crown-6)barium dibromide monohydrate: Synthesis and crystal structures

Two complexes are synthesized: diaquabromo(18-crown-6)rubidium [RbBr(18-crown-6)(H₂O)₂] (I) and triaqua(18-crown-6)barium dibromide monohydrate [Ba(18-crown-6)(H₂O)₃]²⁺ 2Br^? · H₂O (II). The orthorhombic structure of compound I (space group Pnma, a = 10.124 Å, b = 15.205 Å, c = 12.544 Å, Z = 4) and the monoclinic structure of compound II (space group C 2/c, a = 17.910 Å, b = 10.315 Å, c = 14.879 Å, β = 123.23°, Z = 4) are determined by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.063 (I) and 0.042 (II) for all 2293 (I) and 3363 (II) independent measured reflections (CAD-4 automated diffractometer, λMoK _α). The complex molecule [RbBr(18-crown-6)(H₂O)₂] in compound I and the randomly disordered cation [Ba(18-crown-6)(H₂O)₃]²⁺ in compound II are of the host-guest type: their Rb⁺ or Ba²⁺ cation (its coordination number is nine) is located in the cavity of the 18-crown-6 ligand and coordinated by all six O atoms. In structure I, the coordination polyhedron of Rb⁺ is a distorted hexagonal pyramid with a triple apex at the Br^? ligand and two O atoms of the water molecules. In structure II, the Ba²⁺ polyhedron is a distorted hexagonal bipyramid with one apex at the O atom of the water molecule and the other split apex at two O atoms of water molecules.     

Second crystal modification of 1,10-diazonia-18-crown-6 dichloride

The second crystal modification (II) of 1,10-diazonia-18-crown-6 dichloride [H₂DA18C6]²⁺·2Cl^?, where [H₂DA18C6]²⁺ is the 1,10-diaza-18-crown-6 dication (DA18C6) with two protonated nitrogen atoms, was investigated by XRD. The monoclinic modification (II) (space group P2₁/n, a = 9.600 Å, b = 5.689 Å, c = 15.749 Å, β = 91.03°, Z = 2) was solved by direct methods and refined by full-matrix least squares analysis in an anisotropic approximation to R = 0.032 for all 2494 independent reflections collected (CAD-4 automatic diffractometer, λMoK _α). In modification II, the conformation of the DA18C6 dication and the ion packing differ from those in triclinic modification I investigated previously.     

Synthesis and crystal structure of triaqua(18-crown-6)calcium bis(perchlorate) 18-crown-6 monohydrate

A complex [Ca(18C6)(H₂O)₃]²⁺(ClO ₄ ^? · 18C6 · H₂O is synthesized and studied by X-ray diffraction analysis. The structure (space group P2₁/n, a = 11.570 Å, b = 16.024 Å, c = 22.225 Å, β = 98.89°, Z = 4) is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.075 for 5305 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). In the complex cation of the host-guest type, the Ca²⁺ cation lies in the cavity of the 18-crown-6 ligand and is coordinated by all the six O atoms and three O atoms of three water molecules. In a crystal, the alternating complex anions, 18C6 molecules, and water molecules are joined by hydrogen bonds into broad infinite chains along the y axis. The disordered ClO ₄ ^? anions are bonded to these chains on the side through hydrogen bonds.     

Synthesis and crystal structure of aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(perchlorato-O)potassium perchlorate

A new compound, aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(perchlorato-O)potassium perchlorate ([K(DB18C6)(H₂O)]⁺ · [K(ClO₄)(DB18C6)] · ClO ₄ ^? ; compound I) is synthesized and studied by X-ray crystallography. The crystals are triclinic: a = 9.050 Å, b = 9.848 Å, c = 26.484 Å, α = 82.87°, β = 84.16°, γ = 77.93°, Z = 2, space group P $\bar 1$ . The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.058 for 5960 independent reflections (CAD4 diffractometer, λMoK _α radiation). A complex cation [K(DB18C6)(H₂O)]⁺ and a complex molecule [K(ClO₄)(DB18C6)] are of the host-guest type; they are linked into a dimer through two K⁺ → π(C) bonds formed by one of the two K⁺ cations with two C atoms of the benzene ring of the DB18C6 ligand from the adjacent complex. Both DB18C6 ligands in I have a butterfly conformation with approximate symmetry C _2v .     

Syntheses and crystal structures of hydrated complexes of strontium and barium bromides with 18-crown-6

Two complexes, namely, triaqua(18-crown-6)strontium dibromide monohydrate (I) and diaquabromo(18-crown-6)barium bromide (II), are synthesized. Their crystal structures are determined by X-ray diffraction analyses. For complex I, space group C2/c, a = 17.547 Å, b = 10.246 Å, c = 14.786 Å, β = 123.08°, Z = 4. For complex II, space group Pnma, a = 17.753 Å, b = 17.465 Å, c = 6.629 Å, Z = 4. The structures are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.056 (I) and 0.042 (II) for 2696 (I) and 2440 (II) independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). Both complex cations—randomly disordered [Sr(18C6)(H₂O)₃]²⁺ in complex I and [BaBr(18C6)(H₂O)₂]⁺ in complex II—are of the host-guest type. The Sr²⁺ (Ba²⁺) cation resides in the cavity of the 18-crown-6 ligand and coordinated by all six O atoms. In the structures complexes I and II, the coordination polyhedra of the Sr²⁺ and Ba²⁺ cations (coordination number 9) can be described as distorted hexagonal bipyramids with one apex at the O atom of the water molecule in complex I or at the Br^? ligand in complex II and the other split apex at the O atoms of two water molecules.     

(18-Crown-6)sodium tribromide and (18-crown-6)potassium triiodide (with an admixture of bromodiiodide): Synthesis and crystal structure

Two crystalline host-guest complexes are synthesized and studied using X-ray diffraction analysis: (18-crown-6)sodium tribromide [Na(18-crown-6)]⁺ · Br ₃ ^? (I) and (18-crown-6)potassium tribromide (with an admixture of bromodiiodide) [K(18-crown-6)]⁺ · (Br_0.25I_2.75)^? (II). The structures of compound I (space group P2₁/_{n, a} = 8.957 Å, b = 8.288 Å, c = 14.054 Å, β = 104.80°, Z = 2) and compound II (space group Cc, a = 8.417 Å, b = 15.147 Å, c = 17.445 Å, β = 99.01°, Z = 4) are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.098 (I) and 0.036 (II) for all 2311 (I) and 2678 (II) independent measured reflections on a CAD-4 automated diffractometer (λMoK _α). Similar crystalline complexes I and II exist as infinite chains of alternating complex cations and trihalide anions linked to each other through weak Na-Br or K-I coordination bonds. In [Na(18-crown-6)]⁺ and [K(18-crown-6)]⁺ complex cations, the Na⁺ or K⁺ cation (coordination number is eight) is located in the center of the cavity of the 18-crown-6 ligand and coordinated by the six O atoms and two terminal Br or I atoms of two trihalide anions lying on opposite sides of the rms plane of the crown ligand.     

Kronenetherkomplexe von Blei(II). Die Kristallstrukturen von [PbCl(18-Krone-6)][SbCl6], [Pb(18-Krone-6)(CH3CN)3][SbCl6]2, and [Pb(15-Krone-5)2][SbCl6]2

Crown Ether Complexes of Lead(II). The Crystal Structures of [PbCl(18-Krone-6)][SbCl₆], [Pb(18-Krone-6)(CH₃CN)₃][SbCl₆]₂ und [Pb(15-Krone-5)₂][SbCl₆]₂ . [PbCl(18-crown-6)][SbCl₆] has been prepared in low yield besides [Pb(CH₃)₂(18-crown-6)][SbCl₆]₂ by the reaction of Pb(CH₃)₂Cl₂ with antimony pentachloride in acetonitrile solution in the presence of 18-crown-6, forming pale-yellow crystals. The other two title compounds are formed as colourless crystals by the reaction of PbCl₂ with antimony pentachloride in acetonitrile solutions in the presence of 18-crown-6 and 15-crown-5, respectively. The complexes were characterized by IR spectroscopy and by crystal structure determinations. [PbCl(18-crown-6)][SbCl₆]: Space group P2₁/c, Z = 8, 5 003 observed unique reflections, R = 0.046. Lattice dimensions at - 80°C: a = 1 386.9; b = 1 642.7; c = 2 172.1 pm, β = 92.95°. The lead atom in the cation [PbCl(18-crown-6)]⁺ is surrounded in an almost hexagonal-planar construction by the six oxygen atoms of the crown ether and an axially oriented Cl atom. [Pb(18-crown-6)(CH₃CN)₃][SbCl₆]₂: Space group P1 , Z = 2, 6 128 observed unique reflections, R = 0.076. Lattice dimensions at - 70°C: a = 1 228.0; b = 1 422.9; c = 1 463.2 pm, α = 69.08°; β = 65.71°; γ = 64.51°. In the cation [Pb(18-crown-6)(CH₃CN)₃]²⁺ the lead atom is coordinated by the six oxygen atoms of the crown ether and by the three nitrogen atoms of the acetonitrile molecules. The structure determination is restricted by disorder. [Pb( 15-crown-5)₂][SbCI₆]₂: Space group P6₃/m, Z = 6, 5 857 observed unique reflections, R = 0.059. Lattice dimensions at -70°C: a = b = 2 198.5; c = 1499.4 pm, α = β = 90°, γ = 120°. In the cation [Pb(l5-crown-5)₂]² the lead atom is sandwich-like coordinated by the ten oxygen atoms of the two crown ether molecules. The structure determination is restricted by disorder.     

Synthesis and crystal structure of hexaaquamagnesium 18-crown-6 dibromide dihydrate

A new complex compound [Mg(H₂O)₆]Br₂ · 18-crown-6 · 2H₂O(I) is synthesized, and its structure is studied by X-ray diffraction analysis. The crystals are monoclinic: space group P2₁/c, a = 7.128 Å, b = 18.584 Å, c = 9.598 Å, Å = 103.01°, Z = 2; R = 0.039 for 2180 independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). The coordination polyhedron of the Mg²⁺ cation is a slightly distorted octahedron. The 18-crown-6 molecule has the conformation of a distorted crown with the approximate D _3d symmetry. The crystal contains a branched three-dimensional network of intermolecular (interionic) hydrogen bonds.     

Synthesis and crystal structure of (dibenzo-18-crown-6)bis(thiocyanato-S)mercury(II)

A new host-guest complex (dibenzo-18-crown-6)bis(thiocyanato-S)mercury(II), [Hg(SCN)₂(DB18C6], was synthesized and studied by X-ray diffraction method. The crystal structure (space group P2₁/n, a = 19.372, b = 8.199, c = 31.799 Å, β = 103.58°, Z = 8) was solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.092 for 6392 independent reflections; CAD-4 autodiffractometer, λMoK _α. In two independent similar complex molecules, the Hg²⁺ cation lies in the cavity of the DB18C6 crown ligand and is coordinated by all the six O atoms and is covalently bonded to two S atoms of the SCN^? ligands lying on the opposite sides of the mean plane of the six O atoms of the DB18C6 ligand. The coordination polyhedron of two independent Hg atoms is a distorted hexagonal bipyramid. Both independent DB18C6 ligands have the “butterfly” conformation with the approximate C _2v symmetry.     

(18-crown-6)potassium tris(thiocyanato)nickelate(II): Synthesis and crystal structure

A new crystalline complex, (18-crown-6)potassium tris(thiocyanato)nickelate(II), [Ni(SCN)₃K(18-crown-6)] _n (I) was synthesized and studied by X-ray diffraction: space group Cmc2₁, a = 14.749, b = 15.045, c = 10.216 Å, Z = 4, direct method, least-squares full-matrix refinement in anisotropic approximation to R = 0.022 on 2214 independent reflection, CAD-4 automated diffractometer, λMoK _α. In crystal structure I, the [Ni(SCN)₃] _n ^? chains are directed along the axis z with the host-guest [K(18-crown-6)]⁺ fragments attached through the weak K-S bonds to the chains at the side. The complex cations and anions lie in crystallographic plane m. The Ni²⁺ cation has a distorted octahedral coordination. The coordination polyhedron of the K⁺ cation is a distorted hexagonal pyramid with six O atoms of the 18-crown-6 ligand in the base and bifurcate axial vertex at the S and S′ atoms of two SCN^? ligands.     

Tetrakis(isothiocyanato)manganese(II) bis[aqua(18-crown-6)potassium] (18-crown-6)(thiocyanato)potassium

A new complex compound, i.e., tetrakis(isothiocyanato)manganese(II) bis[aqua(18-crown-6)potassium] (18-crown-6)(thiocyanato)potassium, was synthesized and its crystal structure was studied by X-ray diffraction (space group P2₁/m, a = 13.377, b = 14.690, c = 17.499 Å, β = 108.96°, Z = 2) and refined by the least-squares method in anisotropic approximation to R = 0.060 for 4715 independent reflections (CAD-4 automated diffractometer, λMoK _α). In the crystal, infinite chains are formed through the coordination bonds between its components. The monomer fragment of a chain [Mn(NCS)₅K₃(18-crown-6)₃(H₂O)₂] lies in plane m; three of the five SCN^? ligands and one of the two water molecules behave as bridges. The [Mn(NCS)₄]^2? anion has the tetrahedral structure. The coordination polyhedron of each of the three K⁺ cations is a distorted hexagonal bipyramid with six O atom of the corresponding crown ligand in a base. Three 18-crown-6 ligands have standard crown conformation.     

Synthesis and crystal structure of diaqua(trinitrato)iron(III) 18-crown-6

A novel complex adduct, diaqua(trinitrato)iron(III) 18-crown-6, [Fe(NO₃)₃(H₂O)₂] · 18-crown-6, was synthesized and its crystal structure was studied by X-ray diffraction: space group C2/c, a = 10.073, b = 18.069, c = 25.326 Å, β = 91.51°, Z = 8. The structure was solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.076 for 4090 independent reflections (CAD-4 automated diffractometer, λMoK_α). The structure contains isolated complex molecule [Fe(NO₃)₃(H₂O)₂] and two halves of independent molecules 18-crown-6, one of which is statistically disordered about axis 2, while another one is located around the inversion center and is somewhat disordered with respect to the latter. In the complex molecule, the coordination polyhedron of the Fe³⁺ cation is a distorted pentagonal bipyramid with five O atoms of three NO ₃ ^? ligands in a base and two O atoms of two water molecules in the axial vertices. The alternating complex molecules and the disordered 18-crown-6 molecules are joined by hydrogen bonds into “thick” infinite chains along the z axis.     

Ammonium (18-Crown-6)(Triphenylphosphine Oxide) Perchlorate: Synthesis and Crystal Structure

A new compound, ammonium (18-crown-6)(triphenylphosphine oxide) perchlorate (I), is synthesized, and its crystal structure is studied using X-ray diffraction analysis (space group R3m, a = 14.432 Å, c = 14.034 Å, Z = 3, direct method, full-matrix least-squares method in the anisotropic approximation, R = 0.064 for 1945 independent reflections, CAD4 automated diffractometer, λMoKα radiation). In the structure, the NH ₄ ⁺ cation resides in the 18-crown-6 macrocycle cavity and is hydrogen-bonded with three symmetrically equivalent O atoms of the 18-crown-6 molecule and with the phosphoryl O atom of the Ph₃PO molecule. The P=O H-N and Cl atoms occupy the partial position 3m. The oxygen atoms of the ClO ₄ ^? anion are disordered over the 3m position.     

Aquabis(dibenzo-18-crown-6)(tetrabromocuprato(II))dipotassium: Synthesis and crystal structure

The novel complex [K(Db18C6)(H₂O)]⁺[K(Db1)] ⁺(CuBr₄)^2? (I) was obtained. Its crystal structure (space group P2₁/c, a = 17.970 Å, b = 29.838 Å, c = 9.074 Å, β = 103.11°, Z = 4) was studied by X-ray diffraction analysis, solved by the direct method, and refined by the least-squares method in the anisotropic approximation to R = 0.098 from 6220 independent reflections (CAD-4 automated diffractometer, λMo Kα). In both “guest-host” complex ions, the K⁺ cation is in the cavity of the crown ligand Db18C6 and is coordinated by all its O atoms, as well as by a Br atom of the complex anion [CuBr₄]^2? or the water O atom. The coordination of either K⁺ cation is extended to a hexagonal bipyramid by a weak K⁺ → π\((C\dddot ---C)\) bond to two C atoms of the benzene ring of the adjacent ligand Db18C6. In the crystal, the complex anions and cations are united into infinite double chains through the above contacts and the interion hydrogen bonds O-H…Br.     

On the crystal structure of hexathia-18-crown-6

Abstract

Hexathia-18-crown-6 (18-S-6) exhibits a cyclic structure with all the heteroatoms being directed out of the macrocyclic ring (exodentate conformation). In a previous report on a different crystalline modification of this compound, the crown contains two C-S linkages which are anti, rather than all such linkages being gauche. The title compound crystallizes in the monoclinic space group P2₁/c with a = 5.833(1), b = 11.148(1), c = 13.191(1) Å, β = 93.29(1)°, and D_c = 1.404 g cm^?3 for Z = 2. Refinement based on 983 observed reflections led to R = 0.058.     

Synthesis and crystal structure of aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)-(tetrachlorocuprato(II)-Cl)potassium

New mixed complex compound aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(tetrachlorocuprato(II)-Cl)potassium, [K(CuCl₄)(Db18C6)]^? · [K(Db18C6)(H₂O)]⁺, is synthesized and its crystal structure is studied by the method of x-ray structural analysis. The structure includes two independent complex ions, both of guest-host type: two cations K⁺ are located in the respective cavities of the Db18C6 crown-ligand (one in each) and each is coordinated by all its six O atoms and one Cl atom of the anion-ligand [CuCl₄]^2? or O atom of the ligand water molecule. Coordination of these two K⁺ cations is completed to hexagonal pyramidal one by formation by each of unusually weak coordination bond K⁺ → π(\(C\dddot - C\)) with two C atoms of respective benzene ring in the neighboring Db18C6 ligand. In this crystal structure the complex anions and cations form dual infinite chains via these coordination bonds and interionic O-H?Cl hydrogen bonds.     

Interaction of Iodine with Hexaaza-18-crown-6 and Tetraaza-14-crown-4 in Chloroform Solution

Interactions of hexaaza-18-crown-6 (HA18C6) and tetraaza-14-crown-4 (TA14C4) with iodine have been investigated spectrophotometrically in chloroform solution. The observed time dependence of the charge-transfer band and subsequent formation of I₃ ^- in solution were related to the slow transformation of the initially formed 1:1 macrocycle. I₂ outer complex to an inner electron donor-acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion, as follows: macrocycle + I₂→_fast ^K _f macrocycle.I₂ (outer complex) macrocycle.I₂ (outer complex) →^slow (macrocycle.I⁺)I^- (inner complex) macrocycle.I⁺)I^- (inner complex) + I²→^slow (macrocycle.I⁺)I₃ ^-. The pseudo-first-order rate constants at various temperatures for thetransformation process were evaluated from the absorbance-time data. The activation parameters (E_a, Δ H^?, and Δ S^?) for thetransformation were obtained from the temperature dependence of the rate constants. The stoichiometry and formation constants of the resulting EDA complexes have also been determined. It was found that the (TA14C4.I⁺)I₃ ^- is more stable the (HA18C6.I⁺)I₃ ^- complex in chloroform solution.     

Synthesis and crystal structure of dibenzo-18-crown-6 oxonium perchlorate

An ionized crystalline adduct of dibenzo-18-crown-6, perchloric acid, and water (H₃O)[DB 18K6](ClO₄) is synthesized and structurally studied by X-ray diffraction. The crystals are triclinic: a = 8.582 Å, b = 10.486 Å, c = 26.293 Å, α = 79.45°, β = 82.00°, γ = 79.36°, Z = 4, space group P \(\bar 1\). The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.098 for 5936 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). The structure contains two independent DB18C6 molecules, two independent H₃O⁺ ions, and two independent ClO ₄ ^? ions. The H₃O⁺ ions each lie in the cavity of each of the two DB18C6 molecules and are retained there by three strong hydrogen bonds. Two DB18C6 molecules have close geometric parameters and a butterfly conformation with approximate symmetry C _2v . One of the two independent ClO ₄ ^? anions is disordered over two orientations.     

Triaqua(18-crown-6)strontium tetrachlorocuprate(II) hemihydrate: Synthesis and crystal structure

The new complex [Sr(18-crown-6)(H₂O)₃]²⁺[CuCl₄]^2? · 0.42H₂O was obtained; its crystal structure was determined by X-ray diffraction analysis: space group P2₁, a = 10.305 Å, b = 13.570 Å, c = 17.566 Å, β = 98.23 °, Z = 4 (direct method, anisotropic full-matrix least-squares method, R = 0.053 from independent reflections; CAD-4 automated diffractometer, λMoK _α). The asymmetric part of the unit cell comprises two independent “guest-host” complex cations [Sr(18-crown-6)(H₂O)₃]²⁺, two independent complex anions [CuCl₄]^2?, and a hydrate water molecule with a position population of 0.84(1).     

Synthesis and crystal structure of dibenzo-18-crown-6 oxonium perchlorate trihydrate

A hydrated crystalline ionized adduct of dibenzo-18-crown-6 and perchloric acid DB18C6 · H₃O⁺ · CiO ₄ ^? · 3H₂O (I) is synthesized and characterized by X-ray diffraction. The crystals of I are monoclinic: a = 17.760 Å, b = 12.922 Å, β = 124.27°, Z = 4, space group Cc. The structure of I is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 for 3294 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). A DB18C6 molecule has a butterfly conformation with the rough symmetry C _2v . An H₃O⁺ · H₂O dimer is situated on one side of the DB18C6 macrocycle, and the ClO ₄ ^? anion and two other water molecules are on the other side. In the crystal of I, the DB18C6 molecules, H₃O⁺ and ClO ₄ ^? ions, and water molecules are linked through intermolecular (interionic) hydrogen bonds to form broad infinite chains running along the z axis.