Bis(adamantan‐1‐aminium) tetrachloridozincate(II) 18‐crown‐6 monohydrate clathrate

The structure of the title compound [systematic name: bis(adamantan‐1‐aminium) tetrachloridozincate(II)–1,4,7,10,13,16‐hexaoxacyclooctadecane–water (1/1/1)], (C₁₀H₁₈N)₂[ZnCl₄]·C₁₂H₂₄O₆·H₂O, consists of supramolecular rotator–stator assemblies and ribbons of hydrogen bonds parallel to [010]. The assemblies are composed of one protonated adamantan‐1‐aminium cation and one crown ether molecule (1,4,7,10,13,16‐hexaoxacyclooctadecane) to give an overall [(C₁₀H₁₈N)(18‐crown‐6)]⁺ cation. The –NH₃⁺ group of the cation nests in the crown and links to the crown‐ether O atoms through N—H...O hydrogen bonds. The 18‐crown‐6 ring adopts a pseudo‐C_3v conformation. The second adamantan‐1‐aminium forms part of ribbons of adamantan‐1‐aminium–water–tetrachloridozincate units which are interconnected by O—H...Cl, N—H...O and N—H...Cl hydrogen bonds via three different continuous rings with R₅⁴(12), R₄³(10) and R₃³(8) motifs.     

4‐Carboxypyridinium perchlorate 18‐crown‐6 dihydrate clathrate and 4‐carboxypyridinium tetrafluoroborate 18‐crown‐6 dihydrate clathrate

Mixtures of 4‐carboxypyridinium perchlorate or 4‐carboxypyridinium tetrafluoroborate and 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) in ethanol and water solution yielded the title supramolecular salts, C₆H₆NO₂⁺·ClO₄⁻·C₁₂H₂₄O₆·2H₂O and C₆H₆NO₂⁺·BF₄⁻·C₁₂H₂₄O₆·2H₂O. Based on their similar crystal symmetries, unit cells and supramolecular assemblies, the salts are essentially isostructural. The asymmetric unit in each structure includes one protonated isonicotinic acid cation and one crown ether molecule, which together give a [(C₆H₆NO₂)(18‐crown‐6)]⁺ supramolecular cation. N—H...O hydrogen bonds between the protonated N atoms and a single O atom of each crown ether result in the 4‐carboxypyridinium cations `perching' on the 18‐crown‐6 molecules. Further hydrogen‐bonding interactions involving the supramolecular cation and both water molecules form a one‐dimensional zigzag chain that propagates along the crystallographic c direction. O—H...O or O—H...F hydrogen bonds between one of the water molecules and the anions fix the anion positions as pendant upon this chain, without further increasing the dimensionality of the supramolecular network.     

Crystallographic report: Thallium(18‐crown‐6) hexafluorophosphate, [Tl(18‐crown‐6)](PF6)

Thallium(18‐crown‐6) hexafluorophosphate was prepared and its structure was determined by X‐ray diffraction analysis. The Tl⁺ ion is surrounded by six oxygen atoms of 18‐crown‐6 and three fluorine atoms of , forming a sandwiched structure. If the three Tl–F interactions were considered significant, the coordination number in the title compound would be nine. Copyright © 2003 John Wiley & Sons, Ltd.     

(Borohydrido)(18‐crown‐6)potassium and (borohydrido)(dibenzo‐18‐crown‐6)(tetra­hydro­furan)potassium

In the two compounds (borohydrido)(1,4,7,10,13,16‐hexa­oxacyclo­octa­decane‐κ⁶O)potassium, [K(BH₄)(C₁₂H₂₄O₆)], (I), and (borohydrido)(1,4,7,10,13,16‐hexa­oxa‐2,3:11,12‐di­benzo­cyclo­octa­deca‐2,11‐diene‐κ⁶O)(tetra­hydro­furan)­potassium, [K(BH₄)(C₄H₈O)(C₂₀H₂₄O₆)], (II), the K atom is bound to the six O atoms of the crown ether and to a tridentate borohydride group, with further coordination to a tetra­hydro­furan mol­ecule in (II). The alkali metal ion environment is thus distorted hexa­gonal–pyramidal in (I) and bipyramidal in (II).     

Pb(18‐crown‐6)Cl2 and Hg(18‐crown‐6)I2: Molecular Dihalides Trapped in a Crown Ether

Pb(18‐crown‐6)Cl₂ and Hg(18‐crown‐6)I₂ are obtained as transparent colourless crystals of needle and hexagonal shape, respectively, by isothermal evaporation of their dichloromethane solutions. Pb(18‐crown‐6)Cl₂ crystallizes with the trigonal crystal system [ , no. 148, a = b = 1176.3(2), c = 1191.8(3) pm, V = 1428.2(5) 10⁶·pm³, Z = 3] whereas Hg(18‐crown‐6)I₂ crystallizes with the orthorhombic crystal system (Pnma, no. 62, a = 1613.9(2) pm, b = 2822.2(5) pm, c = 841.3(1) pm, V = 3832(1)10⁶·pm³, Z = 8). Both compounds are characterized by linear MX₂ (HgI₂ or PbCl₂) molecular units which are encrypted by the crown ether. In both cases, the divalent metal ion resides in the middle of the crown ether resulting in a hexagonal bipyramidal coordination environment for the metal cations. The molecular symmetry comes close to D_3d. Hg(18‐crown‐6)I₂ and Pb(18‐crown‐6)Cl₂ differ in the way the single MX₂@18‐crown‐6 units are packed. Whereas the Hg(18‐crown‐6)I₂ molecules are arranged in a (distorted) cubic closest packing, the Pb(18‐crown‐6)Cl₂ molecules adopt a hexagonal closest packing.     

A ternary complex of aqua(18‐crown‐6)bis(o‐nitrophenolato)barium(II), the triaqua(18‐crown‐6)(o‐nitrophenolato)barium(II) cation and the o‐nitrophenolate anion

In the title compound [systematic name: tri­aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane‐κ⁶O)(2‐nitro­phenolato‐κO)­barium(II)–aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane‐κ⁶O)‐ bis(2‐nitro­phenolato‐κ²O,O′)­barium(II)–2‐nitro­phenolate (1/1/1)], [Ba(C₁₂H₂₄O₆)(C₆H₄NO₃)(H₂O)₃][Ba(C₁₂H₂₄O₆)(C₆H₄NO₃)₂(H₂O)](C₆H₄NO₃), the two Ba^II atoms encapsulated by the 18‐crown‐6 rings have different coordinations. Although both Ba^II atoms are coordinated to the six O atoms of the crowns, in the neutral moiety, the Ba^II atom is coordinated to one terminal O atom from a water mol­ecule, two phenolate O atoms and two nitro‐group O atoms, while in the cationic moiety, the Ba^II atom is coordinated to three terminal O atoms from water mol­ecules and one phenolate O atom. Both the crowns are eclipsed and translated along the b direction. In the asymmetric unit, the three components are interconnected by four O—H?O interactions. The packing is stabilized by two intermolecular C—H?O interactions and by one O—H?O interaction.     

Barium(II)–2,4‐dinitrophenolate–18‐crown‐6 at 183 K

The title compound, bis(2,4‐dinitrophenolato‐κ²O,O′)(1,4,7,10,13,16‐hexaoxadecane‐κ⁶O)barium(II), [Ba(C₆H₃N₂O₅)₂(C₁₂H₂₄O₆)], is a 1:1 complex of barium(II)–2,4‐di­nitro­phenolate and 1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane (18‐crown‐6). Its structure is located on a crystallographic inversion centre. The temperature dependence of the crystal structure has been studied. The monoclinic β angle of the P2₁/­n space group increases with increasing temperature. The packing structure of the complex is stabilized by intermolecular C—H?O interactions.     

A novel PtII–dibenzo‐18‐crown‐6 (DB18C6) complex

The novel Pt^II–dibenzo‐18‐crown‐6 (DB18C6) title complex, μ‐[tetrakis­(thio­cyanato‐S)­platinum(II)]‐N:N′‐bis{[2,5,8,­15,18,21‐hexa­oxa­tri­cyclo­[20.4.0.1^9,14]­hexa­cosa‐1(22),9(14),10,12,23,25‐hexaene‐κ⁶O]­potassium(I)}, [K(C₂₀H₂₄O₆)]₂[Pt(SCN)₄], has been isolated and characterized by X‐ray diffraction analysis. The structure analysis shows that the complex displays a quasi‐one‐dimensional infinite chain of two [K(DB18C6)]⁺ complex cations and a [Pt(SCN)₄]^2? anion, bridged by K⁺?π interactions between adjacent [K(DB18C6)]⁺ units.     

Hydrated hexacyanometallate(III) salts of triaqua(18‐crown‐6)lanthanoid(III) and tetraaqua(18‐crown‐6)lanthanoid(III) cations containing nine‐ and ten‐coordinate lanthanoids

Tetraaqua(18‐crown‐6)cerium(III) hexacyanoferrate(III) dihydrate, [Ce(C₁₂H₂₄O₆)(H₂O)₄][Fe(CN)₆]·2H₂O, and tetraaqua(18‐crown‐6)neodymium(III) hexacyanoferrate(III) dihydrate, [Nd(C₁₂H₂₄O₆)(H₂O)₄][Fe(CN)₆]·2H₂O, are isomorphous and isostructural in the C2/c space group, where the cations, which contain ten‐coordinate lanthanoid centres, lie across twofold rotation axes and the anions lie across inversion centres. In these compounds, an extensive series of O—H...O and O—H...N hydrogen bonds links the components into a continuous three‐dimensional framework. Triaqua(18‐crown‐6)lanthanoid(III) hexacyanoferrate(III) dihydrate, [Ln(C₁₂H₂₄O₆)(H₂O)₃][Fe(CN)₆]·2H₂O, where Ln = Sm, Eu, Gd or Tb, are all isomorphous and isostructural in the P space group, as are triaqua(18‐crown‐6)gadolinium(III) hexacyanochromate(III) dihydrate, [Gd(C₁₂H₂₄O₆)(H₂O)₃][Cr(CN)₆]·2H₂O, and triaqua(18‐crown‐6)gadolinium(III) hexacyanocobaltate(III) dihydrate, [Gd(C₁₂H₂₄O₆)(H₂O)₃][Co(CN)₆]·2H₂O. In these compounds, there are two independent anions, both lying across inversion centres, and the lanthanoid centres exhibit nine‐coordination; in the crystal structures, an extensive series of hydrogen bonds links the components into a three‐dimensional framework.     

4‐Methoxyanilinium tetrafluoroborate–dibenzo‐18‐crown‐6 (1/1)

In the structure of the complex of dibenzo‐18‐crown‐6 [systematic name: 2,5,8,15,18,21‐hexaoxatricyclo[20.4.0.0^9,14]hexacosa‐1(26),9,11,13,22,24‐hexaene] with 4‐methoxyanilinium tetrafluoroborate, C₇H₁₀NO⁺·BF₄⁻·C₂₀H₂₄O₆, the protonated 4‐methoxyanilinium (MB‐NH₃⁺) cation forms a 1:1 supramolecular rotator–stator complex with the dibenzo‐18‐crown‐6 molecule via N—H...O hydrogen bonds. The MB‐NH₃⁺ group is attached from the convex side of the bowl‐shaped crown, in contrast with similar ammonium cations that nest in the curvature of the bowl. The cations are associated via C—H...π interactions, while the cations and anions are linked by weak C—H...F hydrogen bonds, forming cation–crown–anion chains parallel to [011].     

Di‐μ‐sulfido‐bis[diaqua(18‐crown‐6)­barium(II)]–saccharin (1/2)

The mol­ecule of the title compound {systematic name: di‐μ‐sulfido‐bis[di­aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octade­cane‐κ⁶O)barium(II)] bis­[1,2‐benzisothiazol‐3(2H)‐one 1,1‐dioxide]}, [Ba₂S₂(C₁₂H₂₄O₆)₂(H₂O)₄](C₇H₅NO₃S)₂, lies on an inversion centre. The Ba^II atom encapsulated by the 18‐crown‐6 ring is coordinated by the six O atoms of the crown, two water O atoms and two bridging S atoms. The four‐membered ring composed of the Ba^II atoms and the bridging S atoms makes a dihedral angle of 67.1 (1)° with the crown‐ether ring. The aromatic ring system of the saccharin moiety is essentially planar. The packing is built up from layers of the mol­ecules and is stabilized by three intermolecular O—H?O hydrogen bonds.     

N,N′‐Bis(2‐ammonioethyl)propane‐1,3‐diaminium tris(perchlorate) chloride

The crystal structure of the title compound, C₇H₂₄N₄⁴⁺·3ClO₄⁻·Cl⁻, is mainly determined by electrostatic interactions between the charged species and a number of relatively weak N—H...O and N—H...Cl⁻ hydrogen bonds. The rich structure of such hydrogen bonds creates infinite layers of ions extending along the [001] direction. The tetracation has the gttttttg conformation, similar to the single previously known example of such a cation. The presence of two different anions can be connected with the undecided competition between them, and some of the packing advantages of such a situation are found in the crystal structure.     

1,3:16,18‐Bis­(xylyl)‐30‐crown‐8

The title crown ether, C₂₈H₄₀O₈, crystallizes in an ortho­rhombic cell with the full mol­ecule generated from crystallographic inversion symmetry. The ring consists of 30 atoms which could potentially influence the size of the ring cavity and the conformational flexibility. Unusual C—O—C—C and O—C—C—O torsion‐angle geometries, deviating by as much as 30° from their ideal values, have been observed.     

Isolated pentaiodide anions in [K(18‐crown‐6)]I5

(1,4,7,10,13,16‐Hexaoxa­cyclo­octa­decane‐κ⁶O)­potassium penta­iodide, [K(C₁₂H₂₄O₆)]I₅, obtained by slow evaporation of an ethanol solution of KI, 18‐crown‐6 and I₂, contains [K(18‐crown‐6)]⁺ cations (C_i symmetry) and I₅⁻ anions (C₂ symmetry), which are arranged in alternating layers parallel to (001). In contrast to the well known tendency of I₅⁻ ions to form chains and nets, the I₅⁻ units in the title compound are isolated.     

M(benzo‐18‐crown‐6)I4 (M = Cd,Hg): Tetraiodide,Iodide–Iodine Adduct,or an Inclusion Compound of Iodine in MI2@(benzo‐18‐crown‐6)?

M(benzo‐18‐crown‐6)I₄ (M = Cd, Hg) are obtained as red columnar crystals from the reactions of benzo‐18‐crown‐6 (b18c6), cadmium and mercury iodide, respectively, and iodine in molar ratios of 1:1:2 in acetonitrile. They both crystallize with the orthorhombic crystal system, P2₁2₁2₁, a = 833.7(1), b = 1610.9(1), c = 1846.8(1) pm, V = 2480.3(1) 10⁶·pm³, Z = 4, for M = Cd and a = 823.4(1), b = 1616.5(1), c = 1866.1(1) pm, V = 2483.8(2) 10⁶·pm³ for M = Hg. The crystal structures consist of [M(b18c6)]I₂ molecules which are connected to a slightly lengthened iodine molecule via a secondary contact, according to the formulation I₂@[MI₂@(b18c6)].     

Identification of the Structural Boundary between [Ln(18‐crown‐6)(NO3)3] and [Ln(NO3)3(H2O)3] · 18‐crown‐6 Motifs in the Lanthanide Series

Recrystallization of Ln(NO₃)₃ (Ln = Sm, Eu, Yb) in the presence of 18‐crown‐6 under aqueous conditions yielded [Ln(NO₃)₃(H₂O)₃] · 18‐crown‐6. X‐ray crystallography revealed isomorphous structures for each of the lanthanide complexes where [Ln(NO₃)₃(H₂O)₃] is involved in hydrogen bonding interactions with 18‐crown‐6. The transition point where the structural motif changes from [Ln(18‐crown‐6)(NO₃)₃] (with the metal residing in the crown cavity) to [Ln(NO₃)₃(H₂O)₃] · 18‐crown‐6 has been identified as at the Nd/Sm interface. A similar investigation involving [Ln(tos)₃(H₂O)₆] (tos = p‐toluenesulfonate) and 18‐crown‐6 were resistant to crown incorporation. X‐ray studies show extensive intra‐ and intermolecular hydrogen bonding is present.     

Helicity induction on a poly(phenylacetylene) derivative bearing aza‐18‐crown‐6 ether pendants in water

A stereoregular poly(phenylacetylene) bearing the bulky aza‐18‐crown‐6 ether as the pendant (poly‐ 1 ) formed a predominantly one‐handed helical conformation upon complexation with various chiral compounds, such as amino acids, peptides, aminosugars, amines, and amino alcohols in water. The complexes exhibited an induced circular dichroism (ICD) in the UV–visible region of the polymer main chain. Therefore, poly‐ 1 can be used as a novel probe for determining the chirality of chiral compounds in water. The assay of 19 common free L ‐amino acids gave the same ICD sign at 0 °C except for L ‐phenylalanine. The effects of pH, temperature, guest concentration, and organic solvent content on the ICD during the complexation of poly‐ 1 with chiral compounds were also investigated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1004–1013, 2003     

A three‐component cocrystal: benzoyl(hydroxyimino)acetonitrile–18‐crown‐6–water (2/1/4)

In the title compound, 2C₉H₆N₂O₂·C₁₂H₂₄O₆·4H₂O, the 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) molecule resides across a centre of inversion. The adduct exists as a molecular hydrogen‐bonded complex featuring integration of two kinds of synthons, viz. [(18‐crown‐6)(H₂O)₄] [O...O = 2.8645 (18)–2.9014 (18) Å] and an oxime/aqua ensemble, PhC(O)C(CN)NOH...OH₂ [O...O = 2.5930 (18) Å]. The reliability of the oxime/aqua motif, sustained by the highly acidic cyanooxime, is an essential factor in the construction of multicomponent cocrystals and the accommodation of oxime species in macrocyclic hosts. The supramolecular structure is generated by the alternation of hydrophilic [(18‐crown‐6)(H₂O)₄] layers and bilayers of benzoyl(hydroxyimino)acetonitrile molecules, resulting in stacking interactions between the phenyl and cyano groups of 3.666 (2) Å.     

Propane‐1,2‐diammonium tetrafluoroberyllate

Cocrystallization of the inorganic [BeF₄]^2? unit with the organic moiety [NH₃CH₂CH(NH₃)CH₃]²⁺ results in the three‐dimensional network of the title compound, (C₃H₁₂N₂)[BeF₄] or C₃H₁₂N₂²⁺·BeF₄^2?, created by hydrogen bonds between the protonated ammonium groups and the highly electronegative F atoms of the anion. The structure is described in terms of layers related to each other by crystallographic centres of symmetry.     

Aqua(benzene‐1,3‐dicarboxylato)zinc(II)

The title compound, poly­[[aqua­zinc(II)]‐μ‐benzene‐1,3‐di­carboxyl­ato‐O¹:O^1′:O²], [Zn(C₈H₄O₄)(H₂O)]_n, forms a metal–organic coordination network that consists of tetrahedral Zn atoms bonded to one water mol­ecule and three carboxyl­ate groups. Isophthalate groups bridge the four‐coordinate Zn centers to generate two‐dimensional architectures in the ac plane. These planar zinc isophthalate motifs are linked by infinite C=O?H—O—H interactions along the a axis to form a chiral framework. The observed polar structural pattern originates due to the distorted tetrahedral Zn centers [O—Zn—O 100.7 (2)–136.0 (1)°] and the alignment of the water mol­ecules. Bridging isophthalate groups align to form approximate centrosymmetric motifs.