3,12-Diaza-6,9-diazonia-2,13-dioxotetradecane bis(perchlorate)

The crystal structure of the title diprotonated diacetyltriethylenetetramine (DAT) perchorate salt, C10H24N4O2 2+·2ClO4 −, can be described as a three-dimensional assembly of alternating layers consisting of diprotonated diacetyltriethylenetetramine (H2DAT)2+ strands along [100] and the anionic species ClO4 −. The (H2DAT)2+ cations in the strands are connected via N—H⋯O hydrogen bonding between the acetyl groups and the amine groups of neighbouring (H2DAT)2+ cations. Layers of (H2DAT)2+ strands and perchlorate anions are connected by a network of hydrogen bonds between the NH and NH2 groups and the O atoms of the perchlorate anion. The asymmetric unit consits of one perchlorate anion in a general position, as well as of one cation that is located on a center of inversion.

The crystal structure of the title diprotonated diacetyltriethylenetetramine (DAT) perchorate salt, C 10 H 24 N 4 O 2 2+ Á2ClO 4 À , can be described as a three-dimensional assembly of alternating layers consisting of diprotonated diacetyltriethylenetetramine (H 2 DAT) 2+ strands along [100] and the anionic species ClO 4 À . The (H 2 DAT) 2+ cations in the strands are connected via N-HÁ Á ÁO hydrogen bonding between the acetyl groups and the amine groups of neighbouring (H 2 DAT) 2+ cations. Layers of (H 2 DAT) 2+ strands and perchlorate anions are connected by a network of hydrogen bonds between the NH and NH 2 groups and the O atoms of the perchlorate anion. The asymmetric unit consits of one perchlorate anion in a general position, as well as of one cation that is located on a center of inversion.

Comment
As part of a larger project focusing on TETA and its metabolites as pharmaceutical chelating agents in Diabetes treatment (Cooper et al., 2004, Gong et al. 2006, 2008, Jüllig et al. 2007, Lu et al. 2010, we previously published the detection of a new group of TETA metabolites, N 1 -Monoacetyltriethylenetetramine (MAT) and the N 1 , N 10 -Diacetyltriethylenetetramine (DAT) (Lu et al. 2007), as well as just recently the development of a new selective synthetic route and the characterization of the DAT mono-and dihydrochloride salts (Wichmann et al., 2011).
TETA and its metabolites belong into the polyamine family, ambivalent and multidentate ligands, which are well known for their ability to form a variety of interesting open-chain, macrocyclic and three-dimensional architectures. TETA salts exist in variable protonation states with different anionic species (Ilioudis, et al. 2000, 2003, Elaoud et al. 1999, Fu et al. 2005, Wichmann et al. 2007). Therefore, we investigated the metabolite forms MAT and DAT towards their protonation and complexation behaviour (Wichmann et al., 2011). The obtained crystal structure of the new DAT salt [(H 2 DAT) * 2 ClO 4 ] is described in this paper.
The (H 2 DAT) 2+ cations are arranged as a linear symmetric chain with the terminal NH-CO-CH 3 groups in trans-position to each other (Fig. 1).
The crystal structure consists of a three-dimensional-network, containing alternating assembly of two-dimensional-layers of (H 2 DAT) 2+ cations (Fig. 2) (001) plane. However, the two-dimensional-layers of (H 2 DAT) 2+ cations and the perchlorate anions were stabilized by a network of intermolecular hydrogen bonds between the NH-and NH 2 -groups and the oxygen atoms of the perchlorate anion, with N6-H6B···O2-Cl1-O4···H3-N3 between 2.126 (1) Å and 2.125 (1) Å, ( Table 1). The terminal NH-groups of a (H 2 DAT) 2+ cation binds to an O-atom of a perchlorate anion, which itself bound to an internal NH-group of another (H 2 DAT) 2+ cation and vice versa. Therefore each (H 2 DAT) 2+ cation is connected to four different (H 2 DAT) 2+ cations, two from the above and two from the below layer.

Experimental
The DAT * 2 HCl powder material was synthesized by CarboGen, Switzerland according to literature procedure (Jonas et al. 2006, Wichmann et al. 2011. Cu(ClO 4 ) 2 is commercially available and was used as received. Crystals of the title compound were grown by slow evaporation of an aqueous solution of DAT * 2 HCl and Cu(ClO 4 ) 2 in stoichiometric ratio in water over a period of 6 weeks.  3,12-Diaza-6,9-diazonia-2,13-dioxotetradecane bis(perchlorate)