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The reaction of 2,2-dimethylpropane-1,3-diamine (dmpn) with an excess of concentrated aqueous hydrochloric acid yielded colorless crystals of 2,2-dimethylpropane-1,3-diaminium dichloride, dmpnH2Cl2 (1), in addition to small amounts of a monohydrate, dmpnH2Cl2∙H2O (2). The compounds were studied via X-ray crystallography, IR and Raman spectroscopy, NMR spectroscopy and thermal analysis. Single crystal structure determinations on 1 and 2 showed that dmpnH2Cl2 exists in two polymorphic forms, 1a and 1b. The crystal structure of 1b showed to be much more complex than that of 1a. In the crystal structure of 2, four (dmpnH2)2+ cations and eight chloride anions form a cage constructed by N−H∙∙∙Cl hydrogen bonds. In the center of these cages water dimers with a O∙∙∙O distance of 2.776 (8) Å are present. In addition, a conformational analysis of the 2,2-dimethylpropane-1,3-diaminium cation was performed. The results are compared to the experimental findings of 1a, 1b, 2 and other related hydrogen bonded salt structures from the Cambridge crystallographic structure database (CCDC). Last, a topological classification of the solid-state structures of 1a and 2 was performed and the simplified topological networks are discussed. [ABSTRACT FROM AUTHOR]

The reaction of ytterbium metal with ammonium trifluoroacetate in liquid ammonia resulted in a green substance comprising a substantial amount of ytterbium(II) trifluoroacetate that is a useful precursor for the oxidative synthesis of the new ytterbium(III) compound, [(NH4)1-x(H3O)x]2[Yb6F8-(O2CCF3)12(H2O)4].4H2O (x = 1/4), in aqueous trifluoroacetic acid. This mixed ammonium/oxonium crystalline solid is the first example of a substance containing an octahedro-hexanuclear ytterbium(III) complex with μ3-facecapping fluorido ligands. The main structural features of its [Yb6F8] core are non-bonding Yb...Yb distances and Yb--F bond lengths of 3.7576 (3)-3.9413 (5) and 2.2375 (17)-2.3509 (17) Å, respectively. Yb--O bond lengths involving the O atoms of O,O0-bridging carboxylato ligands and vertexsubstituting aqua ligands are in the ranges 2.23 (4)-2.329 (2) and 2.448 (2)-2.544 (3) Å, respectively. These bond lengths are in accordance with expectations, taking into account lanthanoid contraction. Interestingly, there is a significant ammonium versus oxonium ion site dependence, not only of the hydrate water molecule positions within the solid's hydrogen-bonding framework, but also of the coordination sites of one carboxylato and one aqua ligand in the hexanuclear complex. [ABSTRACT FROM AUTHOR]

The novel coordination polymer [Eu(O2CCF3)2(dmf)2]∞ (1) (dmf = N,N-dimethylformamide) containing europium(II) and the two new compounds (NH4)2[Eu6F8(O2CCF3)12(CF3COOH)6] (2) and (NH4)2[Eu6F8(O2CC2F5)12(C2F5COOH)6]·8C2F5COOH (3), both based on hexanuclear europiate(III) complexes, were synthesized from precursors with a Eu2+ : Eu3+ ratio >1, obtained by reaction of europium metal with ammonium perfluorocarboxylates in liquid ammonia. In the crystal structure of 1 the europium(II) ions are bridged by carboxylate groups and N,N-dimethylformamide to form polymeric chains with Eu2+⋯Eu2+ distances of 408.39(13)–410.49(13) pm. The compound crystallizes in the triclinic space group P1¯ (Z = 2). To the best of our knowledge, this is the first example of a (solvated) perfluorocarboxylate containing a lanthanoid in a subvalent oxidation state. In the crystal structures of 2 and 3 the europium(III) ions are bridged by fluoride ions and carboxylate groups to form hexanuclear complex anions with an octahedral arrangement of the cations. The Eu3+⋯Eu3+ distances are in the range of 398.27(15)–400.93(15) pm in 2 and 395.37(4)–399.78(5) pm in 3, respectively. Both compounds crystallize in the monoclinic space group type P21/n (Z = 4) and are the first examples of octahedro-hexanuclear europium carboxylates for which fluoride is reported as a bridging ligand. In all compounds the oxidation state of europium was monitored via151Eu Mössbauer and photoluminescene spectroscopy. [ABSTRACT FROM AUTHOR]