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  • 1
    ISSN: 1573-1111
    Keywords: Host-guest complex structure ; modified crown ethers ; hydrogen bond ; X-ray structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The twenty-membered macrocycle, 18,19-benzo-1, 16-diaza-4,7,10,13-tetraoxacycloeicosa-17,20-dione, C18H26N2O6 (1), aminosulfuric acid and water form a stoichiometric 1∶1∶1 inclusion compound. The crystal structure of [1·NH 3 + SO 3 − ]·H2O has been determined by X-ray crystallography. The crystal is monoclinic, space groupP21/c, a=7.967(1),b=13.447(3),c=20.779(4) Å, β=90.20(2) Å;Z=4. The finalR-value is 0.0434 for 4638 unique reflections withI〉2σ(I). The structure consists of the 1∶1 molecular complexes between the crown host and aminosulfuric acid revealing hydrogen bonding with the ligand ether and carbonyl oxygen atoms. The complexes are united in the layer-like structure by NH...O host-guest and NH...O=C〈host-host interactions. The water entity forms the second coordination sphere of the compound. Aminosulfuric acid exists in the complex as the zwitterion.
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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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