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Start date: 2020 × DDC: 540 × Version: publishedVersion × Subject: Alumo-siloxanes × WGL Institute: INM ×

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    Transformations of the polycyclic Alumosiloxane Al2(OSiPh2OSiPh2O)3 into new Polycycles and Co(II) and In(III) derivatives of (Ph2SiO)8[Al(O)OH]4
    (Weinheim : Wiley-VCH, 2021) Veith, Michael; Sahin, Fadime; Nadig, Sandra; Huch, Volker; Morgenstern, Bernd
    In the presence of water and amines the etherate of bicyclic Al2(OSiPh2OSiPh2O)3 (II a) can be used to generate novel alumosiloxane polycycles like [O(Ph2SiOSiPh2)O−]2Al2O[O(Ph2SiOSiPh2)O] ⋅ 2 H2N+Et2 (1), [O(Ph2SiOSiPh2)O−]2Al2[O(Ph2Si)O]2 ⋅ 2 HN+Et3 (2), [O(Ph2SiOSiPh2)O−]2Al2[O(Ph2SiOSiPh2)O]2 ⋅ 2 HN+Et3 (3 a, 3 b), which crystallizes in two different phases, and [O(Ph2SiOSiPh2)O−]2Al2[O(Ph2SiOSiPh2)O]2 ⋅ 2 HN+(CH2CH2)3N (4). As a common structural feature of these compounds two aluminum atoms which are incorporated in six-membered Al[O(SiPh2OSiPh2)O−] rings are connected as spiro cyclic centers through oxygen and/or siloxane bridges [(OSiPh2)nO] (n=1, 2) to form an assembly of three fused rings at the aluminum corners. The central ring is either eight- (1, 2) or twelve-membered (3, 4). Alkyl ammonium cations balance the charges and form hydrogen bridges to oxygen atoms of the six membered rings. The pentacyclic (Ph2SiO)8[Al(O)OH]4 (I) can be used indirectly (addition of water) and directly as chelating ligand versus Co(II)Cl and In-CH3 fragments as shown with the isolated and structurally characterized compounds (HN+Et3)2{[(Ph2Si)2O3][Al4(OH)4O2](CoCl)2}2− (5 a, 5 b) and (Ph2SiO)8[AlO(OH)]2[AlO2]2(InCH3) ⋅ 2 O(CH2)4 (6).
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    Acid‐Base Interactions of Pyrazine, Ethyl Acetate, Di‐alcohols, and Lysine with the cyclic Alumosiloxane (Ph2SiO)8[Al(O)OH]4 in View of Mimicking Al2O3(H2O) Surface Reactions
    (Hoboken, NJ : Wiley, 2020) Veith, Michael; Kolano, David; Huch, Volker
    The etherate of (Ph2SiO)8[Al(O)OH]4 can be transformed into the pyrazine adduct (Ph2SiO)8[Al(O)OH]4·3N(C2H2)2N (1), the ethyl acetate adduct (Ph2SiO)8[Al(O)OH]4·3H3C‐C(O)OC2H5 (2), the 1,6‐hexane diol adduct (Ph2SiO)8[Al(O)OH]4·2HO–CH2(CH2)4CH2–OH (3) and the 1,4‐cyclohexane diol adduct (Ph2SiO)8[Al(O)OH]4·4HO–CH(CH2CH2)2CH–OH (4). In all compounds the OH groups of the starting material bind to the bases through O–H···N (1) or O–H···O hydrogen bonds (2, 3, 4) as found from single‐crystal X‐ray diffraction analyses. Whereas in 1 only three of the central OH groups bind to the pyrazines, in 2 two of them bind to the same carbonyl oxygen atom of the ethyl acetate resulting in an unprecedented O–H···O···H–O double hydrogen bridge. The hexane diol adduct 3 in the crystal forms a one‐dimensional coordination polymer with an intramolecularly to two OH groups grafted hexane diol loop, while the second hexane diol is connecting intermolecularly. In the cyclohexane diol adduct 4 all OH groups of the central Al4(OH)4 ring bind to different diols, leaving one alcohol group per diol uncoordinated. These “free” OH groups form an (O‐H···)4 assembly creating a three‐dimensional overall structure. When reacting with (Ph2SiO)8[Al(O)OH]4 lysine loses water, turns into the cyclic 3‐amino‐2‐azepanone, and transforms through chelation of one of the aluminum atoms the starting material into a new polycycle. The isolated compound has the composition (Ph2SiO)12[Al(O)OH]4[Al2O3]2·4 C6H12N2O·6(CH2)4O (5).