The Triple Salt 2(C7H9N4O2)[MoOCl4(H2O)] ⋅ 2(C7H9N4O2)Cl ⋅ (H17O8)Cl Containing a C2‐symmetrical Unbranched H+(H2O)8Zundel type Species in a Framework Composed of Theophyllinium, Aquatetrachloridooxidomolybdate and Chloride Ions

Abstract

AbstractFrom a concentrated hydrochloric acid solution of molybdenum‐(V) chloride and theophylline octaaquahydrogen(1+) tetrakis(theophyllinium) bis[aquatetrachloridooxidomolybdate(1−)] tri‐chloride, C7H9N4O2)4(H17O8)[MoOCl4(H2O)]2Cl3, (1) was obtained. The light emerald green inorganic‐organic hybrid material can be rationalized as a triple salt according to the formula 2(C7H9N4O2)[MoOCl4(H2O)] ⋅ 2(C7H9N4O2)Cl ⋅ (H17O8)Cl. The ions involved are connected by charge‐supported hydrogen bonds to form a 3D framework. The unique H17O8+ moiety features a chain of eight hydrogen bonded water molecules, with the excess proton defining a H5O2+ Zundel‐ion (O⋅⋅⋅O distance 240.3(6) pm) in the middle of the chain, and is placed with crystallographic site symmetry 2. Although engaged in strong O−H⋅⋅⋅O bonding to the neighboring water molecules in the chain (O⋅⋅⋅O distance 262.9(4) pm) and in hydrogen bonding to a carbonyl group of a theophyllinium ion, both the conformation of the H5O2+ unit and the geometry of the very strong central O−H−O bond fit to the C2‐symmetrical global minimum structure of an isolated H5O2+ species. The outer water molecules of the H17O8+ moiety are further engaged in N−H⋅⋅⋅O, O−H⋅⋅⋅Cl and O−H⋅⋅⋅O=C bonds.