Divinyl sulfone cross-linked cyclodextrin-based polymeric materials: synthesis and applications as sorbents and encapsulating agents.

The aim of this study was to evaluate the crosslinking abilities of divinyl sulfone (DVS) for the preparation of novel water-insoluble cyclodextrin-based polymers (CDPs) capable of forming inclusion complexes with different guest molecules. Reaction of DVS with native α-cyclodextrin (α-CD), ß-cyclodextrin (ß-CD) and/or starch generates a variety of homo- and hetero-CDPs with different degrees of crosslinking as a function of the reactants' stoichiometric ratio. The novel materials were characterized by powder X-ray diffraction, electron microscopy and for their sorption of phenol and 4-nitrophenol. They were further evaluated as sorbents with phenolic pollutants (bisphenol A and ß-naphthol) and bioactive compounds (the hormone progesterone and curcumin). Data obtained from the inclusion experiments show that the degree of cross-linking has a minor influence on the yield of inclusion complex formation and highlight the important role of the CDs, supporting a sorption process based on the formation of inclusion complexes. In general, the inclusion processes are better described by a Freundlich isotherm although an important number of them can also be fitted to the Langmuir isotherm with R2 ≥ 0.9, suggesting a sorption onto a monolayer of homogeneous sites.

2-(4-Chloro-phen-yl)-4,5-diphenyl-1-(prop-2-en-1-yl)-1H-imidazole.

The title compound, C24H19ClN2, crystallizes with two independent mol-ecules in the asymmetric unit. The prop-2-enyl substituents on the imidazole rings adopt similar conformations in the two mol-ecules. The 4-and 5-substituted phenyl rings and the benzene ring make dihedral angles of 67.06 (8), 5.61 (8) and 41.09 (8)°, respectively, with the imadazole ring in one mol-ecule and 71.53 (8), 28.85 (8) and 41.87 (8)°, respectively, in the other. The crystal structure features C-H⋯π inter-actions and weak π-π stacking inter-actions [centroid-centroid distances = 3.6937 (10) and 4.0232 (10) Å] between the chloro-phenyl rings, which form a three-dimensional supramolecular structure.

Ethyl 4-anilino-2-methyl-5-oxo-1-phenyl-2,5-di-hydro-1H-pyrrole-2-carboxyl-ate.

In the title compound, C20H20N2O3, the central 2,5-di-hydro-1H-pyrrole ring [r.m.s. deviation = 0.014 (1) Å] is oriented at dihedral angles of 77.81 (6) and 25.33 (6)°, respectively, to the attached phenyl ring and the aniline phenyl ring. An intra-molecular N-H⋯O hydrogen bond occurs. In the crystal, mol-ecules are linked through pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(10) ring motif. Two weak C-H⋯π inter-actions are also observed.

Ethyl 4-(4-chloro-anilino)-1-(4-chloro-phen-yl)-2-methyl-5-oxo-2,5-di-hydro-1H-pyrrole-2-carboxyl-ate.

In the title compound, C20H18Cl2N2O3, the dihedral angles between the central 2,5-di-hydro-1H-pyrrole ring and the phenyl rings are 74.87 (9) and 29.09 (9)°. Intra-molecular N-H⋯O and C-H⋯O hydrogen bonds occur. In the crystal, pairs of N-H⋯O hydrogen bonds link adjacent mol-ecules into inversion dimers and form an R 1 (2)(6)R 2 (2)(10)R 1 (2)(6) ring motif through C-H⋯O hydrogen bonds.

(4E)-4-[(2-Hy-droxy-anilino)methyl-idene]-1-phenyl-pyrazolidine-3,5-dione dimethyl sulfoxide hemisolvate.

The asymmetric unit of the title compound, C16H13N3O3·0.5C2H6OS, is composed of two independent pyrazolidine-3,5-dione mol-ecules and one dimethyl sulfoxide solvent mol-ecule. In each pyrazolidine-3,5-dione mol-ecule, an intra-molecular N-H⋯O hydrogen bond forms an S(5)S(6) motif. In the crystal, pairs of each independent pyrazolidine-3,5-dione mol-ecule are linked by N-H⋯O hydrogen bonds, forming dimers with R 2 (2)(8) motifs. These dimers are connected with the other mol-ecules through the solvent mol-ecules via O-H⋯O hydrogen bonds, forming ribbons along the b-axis direction. C-H⋯π inter-actions connect the ribbons. C-H⋯O interactions also occur.

Amino-[(1H-benzimidazol-2-yl)amino]-methaniminium 4-methyl-benzene-sulfonate.

The asymmetric unit of the title salt, C8H10N5 (+)·C7H7O3S(-), consists of two amino-[(1H-benzimidazol-2-yl)amino]-meth-an-im-inium cations and two 4-methyl-benzene-sulfonate anions. The cations are each stabilized by intra-molecular N-H⋯N hydrogen bonds between the free amino groups and the imine N atoms of the benzimidazole units, forming S(6) ring motifs. In the crystal, cations and anions are linked by N-H⋯O and C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular framework. Two strong π-π stacking inter-actions [centroid-centroid distances = 3.4112 (14) and 3.4104 (14) Å] also occur between the centroids of the imidazole rings of like cations.

(Z)-3-(2-Hy-droxy-eth-yl)-2-(phenyl-imino)-1,3-thia-zolidin-4-one.

In the title compound, C(11)H(12)N(2)O(2)S, the thia-zole and phenyl rings are inclined at 56.99 (6)° to one another. The thia-zole ring is planar with an r.m.s. deviation for the five ring atoms of 0.0274 Å. The presence of the phenyl-imine substituent is confirmed with the C=N distance to the thia-zole ring of 1.2638 (19) Å. The mol-ecule adopts a Z conformation with respect to this bond. The -OH group of the hy-droxy-ethyl substituent is disordered over two positions with relative occupancies 0.517 (4) and 0.483 (4). In the crystal, O-H⋯O hydrogen bonds, augmented by C-H⋯N contacts, form dimers with R(2) (2)(11) rings and generate chains along the b axis. Parallel chains are linked in an obverse fashion by weak C-H⋯S hydrogen bonds. C-H⋯O hydrogen bonds together with C-H⋯π contacts further consolidate the structure, stacking mol-ecules along the b axis.