Preparation and characterization of hexamethylenetetramine N-oxide and some acid adducts

Hexamethylenetetramine N-oxide (4) was isolated from the reaction of hexamethylenetetramine (1) with 30% aqueous hydrogen peroxide. With the two reactants in molar ratio 1 : 2, a 1 : 1 : 1 crystalline adduct (5) of (4) with hydrogen peroxide and water was obtained at temperatures around 10°C, and a 1 : 1 adduct (6) of (4) with formic acid upon warming the reaction mixture to above 30°C. Information pertaining to the nature of compounds (4), (5) and (6) was derived from p.m.r, and X-ray determination of unit cells and space groups. Several 1 : 1 acid adducts similar to (6) were prepared by adding the corresponding acid to an ethanolic solution of (4).

Refinement of the crystal structure of zirconyl chloride octahydrate

The crystal structure of zirconyl chloride octahydrate, ZrOCl2•8H2O, has been refined by the least-squares method with new three-dimensional data. Existence of the [Zr4(OH)8(H2O)16]8+ tetranuclear complex has been confirmed. However, the coordination polyhedron about each zirconium atom differs considerably from the D4d antiprismatic geometry reported previously. It is, in fact, more closely related to the D2d dodecahedron, and has twofold axial symmetry within the limits of experimental error. Mean bond lengths in the [Zr4(OH)8(H2O)16]8+ complex, which approximates closely to D2d point-group symmetry, are: Zr—OH (bridging) = 2.142 ± 0.019 Å and Zr—OH2 (terminal) = 2.272 ± 0.032 Å.