Synthesis and Crystal Structure of M([12]crown-4)2O3 • 1.5 NH3 with M = K, Rb

The two new ozonide compounds K([12]crown-4)(2)O-3 center dot 1.5 NH3 (1) and Rb([12]crown-4)(2)O-3 center dot 1.5 NH3 (2) were synthesized from the binary alkali metal ozonides and [12]crown-4 in liquid ammonia. The air- and temperature-sensitive red, needle-shaped compounds crystallize isostructurally in the non-centrosymmetric space group Fdd2 (no. 43) with 16 formula units per unit cell. The lattice parameters are a = 26.917(8), b = 43.25(1), c = 7.823(2) angstrom, V = 9108(5) angstrom(3); and a = 26.730(6), b = 44.70(1), c = 7.739(2) angstrom, V = 9245(4) angstrom(3) for 1 and 2, respectively. The structure comprises rod-like [([M([12]crown-4)(2)(NH3)]O-3)(2)(NH3)] supramolecular units, forming a fishbone pattern parallel to (001). The ozonide anions are separated froth the metal cations and interact only weakly with two ammonia molecules via N-H center dot center dot center dot O hydrogen bonds.