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  • 1
    ISSN: 1572-8854
    Keywords: Inclusion complexes ; antimony fluoride ; crown ethers ; X-ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Four crystalline molecular complexes between antimony(III) fluoride and 18-membered crown ethers have been obtained and their structures investigated by single crystal X-ray diffraction techniques: [18-crown-6·SbF3], C12H24F3O6Sb,P212121,a=8.328(4),b=11.573(4),c=18.094(4)Å,V=1744(1)Å3,Z=4; [benzo-18-crown-6·SbF3], C16H24F3O6Sb,P21/n,a=10.490(2),b=13.714(1),c=13.442(2)Å, β=101.94(1)°,V=1892(1)Å3,Z=4; [cis-syn-cis-dicyclohexano-18-crown-6·SbF3·CH3OH], C21H40F3O7Sb,P21/n,a=8.270(4),b=23.386(3),c=12.772(1)Å, β=96.31(2)°,V=2455(1)Å3,Z=4; [cis-anti-cis-dicyclohexano-18-crown-6·SbF3], C20H36F3O6Sb,Pna21,a=21.091(8),b=12.829(5),c=8.437(3)Å,V=2283(2)Å3,Z=4. All species are the perching-type complexes with the antimony fluoride above the cavity and the metal lone pair pointed toward the center of the crown ring. The antimony atom interacts with all six crown oxygen atoms with Sb−O distances of 2.837(2)–3.344(2) Å. The antimony atom is displaced from the least square plane of the crown oxygen atoms at the distances of 1.288–1.383 Å.
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  • 2
    ISSN: 1572-8854
    Keywords: host–guest complexes ; antimony trifluoride ; azacrown ethers ; X-ray structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Synthesis and single-crystal X-ray structures are recorded for three adducts of SbF3 with different azacrown ethers. [SbF3·H2O·L1], 1, (L1 = 12,13-benz-1,10-di(azamethyl)-4,7-dioxacyclotetradecane-1,14-dione), triclinic, $$P\bar 1$$ , a = 11.234(2), b = 11.691(2), c = 8.869(2) Å, α = 94.66(3), β = 113.12(3), γ = 67.82(3)°, Z = 2. [SbF3Cl·H2O·(HL2)], 2, (L2 = monoaza-18-crown-6), orthorhombic, P212121, a = 8.763(2), b = 13.003(3), a = 16.836(3) Å, Z = 4. [(SbF3)2Cl2·(H2L3)], 3, (L3 = 1,10-diaza-18-crown-6), triclinic, $$P\bar 1$$ , a = 8.284(2), b = 9.016(2), c = 9.134(2) Å, α = 82.92(3), β = 65.24(3), γ = 63.38(3)°, Z = 1. All three structures include SbF3 neutral molecules in the pyramidal mode and the antimony second coordination sphere is completed up to six in different fashions. In 1 the dimeric (SbF3)2 adducts are made up due to the involvement of the symmetry-related fluorine atom in coordination. The distorted octahedron is then completed by water molecule and carbonyl oxygen of L1. The neutral molecules are joined by coordination and hydrogen bonds in the infinite ribbons. 2 and 3 are both comprised of neutral and charged species also bounded via coordination and hydrogen bonds. L2 and L3 in the complexes adopt the form of single and double-charged cations, respectively. The inorganic backbone unites the neutral SbF3 molecules and chloride anions in the alternative mode. The sixth coordination site in the antimony polyhedron is completed by the water molecule in 2 and the ethereal oxygen atom in 3. Alignment of the inorganic entities within the structures of 2 and 3 is strikingly similar. Hydrogen bonding patterns are discussed.
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  • 3
    ISSN: 1573-1111
    Keywords: Host-gues molecular recognition ; H-bonds ; crown ether molecular complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of thecis-anti-cis isomer of dicyclohexano-18-crown-6 with a mixture of 2-chloro-5-methylbenzenesulphamide and 3-chloro-6-methylbenzenesulphamide gives a crystalline product which has been characterized using X-ray crystallography. The complex (I) contains both isomers in a 83.0 (0.6):17.0 (0.6) ratio in favour of the 3-chloro-6-methyl-isomer. The joint crystallization of the crown ether with the mixture of the guest isomers might serve as a route for the partial extraction of one of them. The complex with host: guest ratio 1:2 crystallizes in a triclinic space group $$P\bar 1$$ ,a=13.087(4),b=9.217(2),c=8.120(2) Å, α=92.05(3),β=100.52(3), γ=80.64(2)°, withZ=1. The structure was refined toR=0.041. Each of two equivalent guest molecules interacts with the macrocyclic ring by two NH...O hydrogen bonds, with N...O distances of 2.912(5) and 3.040(5) Å.
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  • 4
    ISSN: 1573-1111
    Keywords: 12-membered crown ethers ; crystal structure ; conformation peculiarities ; X-ray analysis ; CH...O contacts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal structures of two 12-membered crown ethers, benzo-12-crown-4 (1) and naphtho-12-crown-4 (2), have been determined by X-ray analysis. Both structures are molecular. Compound1 is monoclonic,P21/b,a=8.466(3),b=8.019(3),c=33.590(10) Å, γ=90.99(3)o. The unit cell contains two crystallographically independent molecules of1 with similar conformations. Compound2 is also monoclinic,P21/a,a=24.148(8),b=14.535(4),c=7.987(5) Å, γ=102.87(2)o. Two independent molecules in the unit cell have significantly different conformations.
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  • 5
    ISSN: 1573-1111
    Keywords: X-ray crystal structure ; crown ether-potassium complex ; trichlorocuprates ; clathrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The structure of the trichlorocuprate of naphtho-15-crown-5 complexed potassium has been determined by X-ray analysis. The crystal contains the complex cations [K(naphtho-15-crown-5)2]+, the anion [Cu2Cl6]2− and water molecules. The full composition of the compound in the solid state is represented by the formula [K(naphtho-15-crown-5)2]2[Cu2Cl6]·nH2O), wheren≌3. The sandwich type cations are similar to those found previously for potassium complexes with benzo-15-crown-5. The coordination number of potassium is equal to 10; the coordination polyhedron is a 15-crown-5. The coordination number of potassium is equal to 10; the coordination polyhedron is a pentagonal antiprism. The water molecules are disordered and occupy six symmetrically independent positions with a probability of ∼0.5 in the crystal. The lack of close contacts between water molecules and the remaining components enabled the treatment of the complex as a clathrate.
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  • 6
    ISSN: 1573-1111
    Keywords: 12-Crown-4 ; aminosulfuric acid ; host-guest complex structure ; symmetric disparity ; H-bonds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title compound was prepared by treating a methanolic solution of 12-crown-4 with an aqueous solution of aminosulfuric acid. The crystal for X-ray analysis was obtained by recrystallization from acetone. The compound [(12-crown-4)4·[NH3SO3)6] (1) is monoclinic, space groupP21/a,a=21.900(8),b=15.499(5),c=18.079(5) Å, γ=67.85(2)°. Refinement led to a final conventionalR value of 0.0788 for 3280 reflections.
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  • 7
    ISSN: 1573-1111
    Keywords: 18-crown-6 ; diaminofurazane ; crystal structure ; host-guest complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An X-ray—diffraction study is reported for two molecular complexes containing 3,4-diamino-1,2,5-oxadiazole as guest (G) with 18-crown-6 (18-C-6) andcis-anti-cis-dicyclohexano-18-crown-6 (DCH-6B) as host. Both complexes are of the polymeric-chain structure with the guest molecule bridging two crown neighbours. ComplexI: [18-C-6*G*H2O], 1∶1∶1, monoclinic,P21/n,a=8.171(1),b=15.042(2),c=16.209(6) Å, β=101.15(2)°, finalR-factor 0.068. ComplexII: [DCH-6B*G], 1∶1, monoclinicC2/c,a=21.212(4),b=9.380(2),c=13.049(3) Å, β=108.61(3)°, finalR 0.047.
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  • 8
    ISSN: 1573-1111
    Keywords: Molecular recognition ; crystalline inclusion complexes ; X-ray crystal structures ; H-bonding ; crown ethers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This review deals with the problem of the interaction of Si(IV), Ge(IV) and B(III) fluorides with crown ethers and their aza analogues. The crystallographic structures have been determined of the stable products obtained by the interaction of H2SiF6 solution with the following crown ethers: 18-crown-6 (18C6), monoaza-18C6 (MA18C6), 1,10-diaza-18C6 (DA18C6) and 1,7-diaza-15C5 (DA 15C5). The complexes obtained are stabilized by a system of H-bonds of the O-H... O, N-H. ... O, N-H...F and O-H ... F types. For H2GeF6 the adducts obtained are similar to those obtained using H2SiF6. The crystal structures of three new boron fluoride-containing complexes with 18-membered crown ethers are also described. During macrocycle complexation the guest entities undergo chemical transformations which are stabilized by creation of the H- bond system. The results of vibrational and NMR spectra are also discussed.
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  • 9
    ISSN: 1573-1111
    Keywords: Tetraazamacrocycle ; host—guest complementarity ; inclusion compound ; H-bonds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Novel complementary associations have been found in a crystalline ternarycomplex of the macrocyclic tetramine, [12]aneN4 (e.g. =1,4,7,10-tetraazacyclododecane, cyclen, L), hexafluorosilicate ions andwater (I). The final compound belongs to the host—guest type with themacrocycle as the host (H), the inorganic entity as a guest (G) and watermolecules. It was characterized by X-ray techniques, IR spectroscopy andthermogravimetric study. X-ray crystal analysis revealed that the structureis built of the charged entities, with a 3D-network uniting thequadriprotonated form of the macrocycle, hexafluorosilicate as counterionsand lattice water molecules viaN—H+...F-,N—H+...O(w),OH...F- and O—-H(w)...O(w)hydrogen bonds. The overall complex stoichiometry comprises fourSiF6 2- anions and seven water molecules per two[LH4]4+ cations. Crystals of (I) are monoclinic,space group P21/n with a = 14.585(3), b = 16.384(2), c =16.500(3) Å, β = 92.84(3)°, V = 3938(1)Å3 and Z = 8 forC8H31F12N4O3.5Si2.
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  • 10
    ISSN: 1573-1111
    Keywords: X-ray structure analysis ; inclusion compound ; heterocalix[8]arene host ; ethyl acetate guest ; water clustering ; hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The X-ray crystal structure of the solvent inclusion compound formed between heterocalix[8]arene 1, ethyl acetate and water (1 : 1 : 4.5) has been studied. The compound crystallized in tetragonal space group I41/a, a = b = 21.278(3), c = 31.290(4) Å, V = 14167(4) Å3, Z = 8. The host molecule, incorporating benzimidazol-2-one and 2,5-dimethoxy-1,3-phenylene subunits in an alternate cyclic arrangement, forms an almost perfectly closed cavity which encapsulates one solvent ethyl acetate guest molecule. Water molecules being entrapped in the lattice cages in the form of cyclic and linear clusters bind the bulky inclusion complexes via H-bonds in infinite layers. Two symmetry center related benzimidazole-2-one moieties of two hosts from neighbouring layers in the crystal lattice are arranged such that they partially overlap exhibiting stacking interaction.
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