title: N,N'-Bis(pyridin-2-yl)benzene-1,4-diamine-quinoxaline (2/1).
abstract: The asymmetric unit of the title compound, 2C(16)H(14)N(4)·C(8)H(6)N(2), consits of one mol-ecule of N,N'-bis-(pyridin-2-yl)benzene-1,4-diamine (PDAB) and one half-mol-ecule of quinoxaline (QX) that is located around an inversion centre and disordered over two overlapping positions. The PDAB mol-ecule adopts a non-planar conformation with an E configuration at the two partially double exo C N bonds of the 2-pyridyl-amine units. In the crystal, these self-complementary units are N-H⋯N hydrogen bonded via a cyclic R(2) (2)(8) motif, creating tapes of PDAB mol-ecules extending along [010]. Inversion-related tapes are arranged into pairs through π-π stacking inter-actions between the benzene rings [centroid-centroid distance = 3.818 (1) Å] and the two symmetry-independent pyridine groups [centroid-centroid distance = 3.760 (1) Å]. The QX mol-ecules are enclosed in a cavity formed between six PDAB tapes.
authors.affiliation: Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznań,  Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Wicher
authors.forename: Maria
authors.initials: M
authors.lastname: Gdaniec