Szalay Paul S, Zeller Matthias, Hunter Allen D
Acta Crystallogr Sect E Struct Rep Online. 2011 Feb 16;67(Pt 3):o644. doi: 10.1107/S1600536811004843.
In the title compound, C(16)H(28)N(4)O(8)·2H(2)O, the 12-membered macrocycle has twofold crystallographic symmetry and the asymmetric unit comprises one half-mol-ecule. The four carbox-yl/carboxyl-ate groups reside on the same side of the macrocycle. The mol-ecule is a double zwitterion with two of the carb-oxy-lic acid H atoms transferred to the two N atoms on the opposite sides of the macrocycle, resulting in both N atoms having positive charges and leaving the two resulting carboxyl-ate groups with negative charges. The two remaining carb-oxy-lic acid groups and the carboxyl-ate groups form O-H⋯O hydrogen bonds with the crystal water mol-ecules. The H atoms bound to the N atoms within the macrocyle are engaged in two equivalent hydrogen bonds with the adjacent N atoms.
在标题化合物C(16)H(28)N(4)O(8)·2H(2)O中，12元大环具有二重晶体学对称性，不对称单元包含半个分子。四个羧基/羧酸盐基团位于大环的同一侧。该分子是一个双两性离子，其中两个羧酸H原子转移到大环相对侧的两个N原子上，导致两个N原子都带正电荷，而两个生成的羧酸盐基团带负电荷。其余的两个羧酸基团和羧酸盐基团与结晶水分子形成O-H⋯O氢键。大环内与N原子相连的H原子与相邻的N原子形成两个等效的氢键。
