title: A hydrogen-bridged adduct 3,4,6,7,8,9-hexa-hydro-2H-pyrimido[1,2-a]pyrimidin-1-ium [1,3-bis-(tert-butyl-dimethyl-sil-yloxy)-1,3-bis-(pyridin-2-yl)propan-2-yl-idene]nitro-nate acetonitrile monosolvate.
abstract: The title compound, C(7)H(14)N(3) (+)·C(25)H(40)N(3)O(4)Si(2) (-)·CH(3)CN, was obtained by the reaction of 2-nitro-1,3-di(pyridin-2-yl)-1,3-di(tert-butyl-dimethyl-sil-yloxy)propane with 1,3,4,6,7,8-hexa-hydro-2H-pyrimido[1,2-a]pyrimidine. Two hydrogen bonds stabilize the Lewis acid/base pair of the nitro-nate and the guanidinium moiety with N⋯O distances of 2.772 (3) and 2.732 (3) Å. Both hydrogen atoms are more closely bound to the guanidinium [N-H distances of 0.83 (3) and 0.93 (3) Å] than to the nitro-nate moiety. The nitro-nate is double-bonded to the respective carbon with an N=C bond length of 1.316 (3) Å.
authors: Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität, Jena, Humboldt-Strasse 8, 07743 Jena,  Germany.
authors: Martin
authors: M
authors: Schulz
authors: Helmar
authors: H
authors: Görls
authors: Matthias
authors: M
authors: Westerhausen