Hydrogen bonding 5-nitrobarbiturate

Hydrogen-Bonded Networks Constructed with 5-Nitrobarbiturate... 

Two channels of different sizes exist in the crystal structure of inclusion complex 5 [25], As shown in Figure 8.11, two independent 5-nitrobarbiturate anions are linked in the para-to-para fashion by N-H- -O hydrogen bonds to form a dimer, and successive dimers related by the a translation associate in the ortho-to-ortho fashion to generate an approximately planar zigzag ribbon. 

Figure 8.11 Zigzag ribbon formed by 5-nitrobarbiturate ions and the hydrogen-bonded scheme in the thiourea-anion host lattice of 5, viewed along the b axis. The large spheres represent (CH3)4N+ ions. Symmetry transformation a(1 -yx, y, z)...

In this crystal structure, there is no intermolecular interaction between 5-nitrobarbiturate ions [25]. Figure 8.17 shows a portion of a hydrogen-bonded layer viewed along the a axis. 

Scheme 8.2 The nitrobarbiturate-urea connection modes found in hydrogen-bonded complexes type D (para shoulder-to-shoulder), type E (ortho shoulder-to-shoulder) and type F (head-to-tail)...

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