2,25-Dioxo-27,28-diphenyl-30-oxa-29-thia-3,10,17,24-tetraazapentacyclo[24.2.1.112,15.04,9.018,23]triaconta-5,7,9(4),10,12,14,16,18,20,22,26,28-dodecaene chloroform disolvate

The macrocycle of the title compound, C36H24N4O3S·2CHCl3, contains a rigid framework with the nitrogen and oxygen heteroatoms pointing in towards the center of the macrocyclic cavity. The macrocycle is essentially planar (r.m.s. deviation = 0.027 Å) except for the thiophene ring. The dihedral angle between the thiophene ring plane and the mean plane of the central macrocyclic core including all atoms except sulfur is 21.6 (1)°. Four intramolecular hydrogen bonds occur: two are between the amide hydrogen atoms and the Schiff base nitrogen atoms, while the others are between the amide hydrogen atoms and the sulfur atom of the thiophene. The two solvate chloroform molecules are bound to the carbonyl oxygen atoms of the ligand by weak C—H⋯O hydrogen bonding. In addition, the structure reveals intermolecular Cl⋯Cl close contacts [3.308 (2), 3.404 (2) and 3.280 (2) Å] between the chloroform solvate molecules. In the crystal, the macrocycles form layers parallel to (101), with an interlayer distance of 3.362 (3) Å. This short distance is determined by the stacking interactions between the amide carbonyl and imine fragments of neighboring ligands.

The macrocycle of the title compound, C 36 H 24 N 4 O 3 SÁ2CHCl 3 , contains a rigid framework with the nitrogen and oxygen heteroatoms pointing in towards the center of the macrocyclic cavity. The macrocycle is essentially planar (r.m.s. deviation = 0.027 Å ) except for the thiophene ring. The dihedral angle between the thiophene ring plane and the mean plane of the central macrocyclic core including all atoms except sulfur is 21.6 (1) . Four intramolecular hydrogen bonds occur: two are between the amide hydrogen atoms and the Schiff base nitrogen atoms, while the others are between the amide hydrogen atoms and the sulfur atom of the thiophene. The two solvate chloroform molecules are bound to the carbonyl oxygen atoms of the ligand by weak C-HÁ Á ÁO hydrogen bonding. In addition, the structure reveals intermolecular ClÁ Á ÁCl close contacts [3.308 (2), 3.404 (2) and 3.280 (2) Å ] between the chloroform solvate molecules. In the crystal, the macrocycles form layers parallel to (101), with an interlayer distance of 3.362 (3) Å . This short distance is determined by the stacking interactions between the amide carbonyl and imine fragments of neighboring ligands.

Comment
The ubiquity of anions in nature makes an understanding of biological anion-receptor interactions a topic of considerable current interest (Caltagirone & Gale, 2009). It is also inspiring the synthesis of synthetic anion receptors, systems whose potential utility could span the full spectrum of applications from separations and waste remediation to biomedical analysis and therapy (Aydogan et al., 2008). We are particularly interested in the design of rigid macrocyclic hosts for anions and use for this purpose aromatics linked by amide or imine bonds. These bonds and pyrrole rings serve as efficient coordination site for anions functioning by means of hydrogen bonds. In our previous works, it has been shown that rigid scaffold of a receptor results in a higher selectivity that the one with flexible skeleton (Sessler et al., 2005a,b). In this work, we present the new receptor bearing furan and thiophen-2,5-dicarboxamide units in one macrocycle.
The target receptor was synthesized according to the method of template synthesis using chloride anion as a template.
The dialdehyde (2,5-diformylfuran) and diamine (N,N'-bis(2-aminophenyl)-3,4-diphenylthiophen-2,5-dicarboxamide) were condensed in the presence of hydrochloric acid affording hydrochloric acid salt of the macrocyclic receptor I. The HCl that was subsequently neutralized by triethylamine to give free base ligand I (Fig. 1). The single crystals of I suitable for X-ray diffraction analysis were obtained by slow crystallization from chloroform-methanol mixture.
The title compound I crystallizes as a solvate with two chloroform molecules, i. e., C 36 H 24 N 4 O 3 S . 2CHCl 3 . The macrocycle I contains a rigid framework with the N1, N2, O2, N3 and N4 heteroatoms pointing in toward the center of the macrocyclic cavity (Fig. 2). It is practically planar excepting for the thiophene ring. By the intermolecular C-H···O hydrogen bond (Table 1), the phenyl group at the C3 carbon atom of the thiophene forces this ring to deviate from the plane of the central macrocyclic core passed through the C1/C4/C5/N1/C6/C7/N2/C12/C13/O2/C16/C17/N3/C18/C19/N4/C24 atoms (the dihedral angle is 21.6 (1)°. There are four internal hydrogen bonds in I. Two are between the amide NH protons and the Schiff base nitrogen atoms, while the other are between the amide NH protons and the sulfur atom of the thiophene ( Table   1). The two solvate chloroform molecules are bound to the carbonyl oxygen atoms of the ligand by weak C-H···O hydrogen bonding (Table 1). In addition to these effects, the structure reveals the intermolecular Cl···Cl attractive interactions between the chloroform solvate molecules (Cl1···Cl3 ii , Cl1···Cl4 iii and Cl2···Cl5 iv distances are 3.308 (2)Å, 3.404 (2)Å and 3.280 (2)Å, respectively). In the crystal, the macrocycles I form the layers parallel to (101), with the interlayer distance of 3.362 (3)Å (Fig. 3). This short distance is determined by the stacking interactions between amide carbonyl and imine fragments of neighboring ligands. Symmetry codes: (ii) x, -y+1/2, z-1/2; (iii) x-1, y, z; (iv) x-1, y, z+1.