title: Two new "onium" fluorosilicates, the products of interaction of fluorosilicic acid with 12-membered macrocycles: structures and spectroscopic properties.
abstract: Two novel compounds, (L(1)H)(2)[SiF(6)] x 2H(2)O (1) and (L(2)H)(2)[SiF(5)(H(2)O)](2) x 3H(2)O (2), resulting from the reactions of H(2)SiF(6) with 4'-aminobenzo-12-crown-4 (L(1)) and monoaza-12-crown-4 (L(2)), respectively, were studied by X-ray diffraction and characterised by IR and (19)F NMR spectroscopic methods. Both complexes have ionic structures due to the proton transfer from the fluorosilicic acid to the primary amine group in L(1) and secondary amine group incorporated into the macrocycle L(2). The structure of 1 is composed of [SiF(6)](2-) centrosymmetric anions, N-protonated cations (L(1)H)(+), and two water molecules, all components being bound in the layer through a system of NH[...]F, NH[...]O and OH[...]F hydrogen bonds. The [SiF(6)](2-) anions and water molecules are assembled into inorganic negatively-charged layers via OH[dot dot dot]F hydrogen bonds. The structure of 2 is a rare example of stabilisation of the complex anion [SiF(5)(H(2)O)](-), the labile product of hydrolytic transformations of the [SiF(6)](2-) anion in an aqueous solution. The components of 2, i.e., [SiF(5)(H(2)O)](-), (L(2)H)(+), and water molecules, are linked by a system of NH[...]F, NH[...]O, OH[...]F, OH[dot dot dot]O hydrogen bonds. In a way similar to 1, the [SiF(5)(H(2)O)](-) anions and water molecules in 2 are combined into an inorganic negatively-charged layer through OH[...]F and OH[...]O interactions.
authors.affiliation: Physico-Chemical Institute of Environment and Human Protection, Ministry of Education and Science of Ukraine and National Academy of Sciences of Ukraine, Preobrazhenskaya str. 3, 65026 Odessa, Ukraine.
authors.forename: Vladimir O
authors.initials: VO
authors.lastname: Gelmboldt
authors.forename: Eduard V
authors.initials: EV
authors.lastname: Ganin
authors.forename: Marina S
authors.initials: MS
authors.lastname: Fonari
authors.forename: Yurii A
authors.initials: YA
authors.lastname: Simonov
authors.forename: Larisa V
authors.initials: LV
authors.lastname: Koroeva
authors.forename: Alim A
authors.initials: AA
authors.lastname: Ennan
authors.forename: Stepan S
authors.initials: SS
authors.lastname: Basok
authors.forename: Sergiu
authors.initials: S
authors.lastname: Shova
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Kählig
authors.forename: Vladimir B
authors.initials: VB
authors.lastname: Arion
authors.forename: Bernhard K
authors.initials: BK
authors.lastname: Keppler
mesh_terms: D018360:Crystallography, X-Ray; D005459:Fluorides / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D047028:Macrocyclic Compounds / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D009861:Onium Compounds / Q000737:chemistry*; D011522:Protons; D012824:Silicic Acid / Q000737:chemistry* / Q000378:metabolism; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D047028:Macrocyclic Compounds; D009861:Onium Compounds; D011522:Protons; D012824:Silicic Acid; C035291:hexafluorosilicic acid; D005459:Fluorides