ß-Cyclodextrin duplexes that are connected through two disulfide bonds: potent hosts for the complexation of organic molecules.

New tubular host molecules, which are composed of two ß-cyclodextrin macrocycles that are connected through two disulfide bonds, have been prepared by the air-promoted oxidation of 6(I),6(IV)-dideoxy-6(I),6(IV)-disulfanyl-ß-cyclodextrin in aqueous solution. This reaction leads to three products: monomeric intramolecular disulfide and two dimeric species, which are termed as "non-eclipsed" and "eclipsed" cyclodextrin duplexes. Oxidation at a concentration of the starting thiol of 0.1 mM gave the intramolecular disulfide as the major product whereas a concentration in the millimolar range afforded the dimeric species as the dominant products. The tubular structure of the "non-eclipsed" isomer was unequivocally determined by X-ray analysis. The binding affinities of the duplexes to a wide range of compounds, including fluorescent dyes and clinically used drugs Imatinib and Esomeprazol, were studied in water by ITC. For most guest compounds, the experimentally determined K(a) values were in the range 10(7)-10(8) M(-1). These binding affinities are significantly higher than those found in the literature for analogous complexes with native cyclodextrins. In cases of binding of neutral or anionic guest molecules cyclodextrin duplexes outperformed cucurbiturils. A complex between a duplex and Nile blue was used to investigate its ability to penetrate the cytoplasmic membrane of HeLa cells. We found that the complex accumulated in the cell membrane but did not pass into cytosol. Importantly, the complex did not decompose to a significant extent under high dilution in the cellular environment.

Methyl 2-{4-chloro-2-[5-chloro-2-(2-meth-oxy-2-oxoeth-oxy)benz-yl]phen-oxy}acetate.

In the crystal structure of the title compound, C(19)H(18)Cl(2)O(6), mol-ecules are connected via weak C-H⋯π inter-actions into closely packed dimers.

2-Amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium chloride.

In the crystal structure of the title compound, C(4)H(8)N(3)O(+)·Cl(-), N-H⋯Cl hydrogen bonds link the components into chains along [010]. In addition, weak C-H⋯Cl hydrogen bonds link the chains into a two-dimensional network perpendicular to (001).

2,17-Dichloro-8,9,10,11-tetra-hydro-19H-dibenzo[k,n][1,10,4,7]dioxadiaza-cyclo-penta-decine-7,12(6H,13H)-dione.

In the crystal structure of the title compound, C(19)H(18)Cl(2)N(2)O(4), N-H⋯O hydrogen bonds link the mol-ecules into infinite chains along the b axis. The structure also features weak C-H⋯O and C-H⋯Cl hydrogen bonds and C-H⋯π and (lone pair)⋯π inter-actions [Cl⋯centroid = 3.5871 (7) Å]. An intra-molecular N-H⋯O bond occurs.

5,11,17,23,29,35-Hexa-tert-butyl-37,38,39,40,41,42-hexa-kis-(eth-oxy-carbonyl-meth-oxy)calix[6]arene acetonitrile disolvate.

In the title compound, C(90)H(120)O(18)·2CH(3)CN, the calix[6]arene has a 1,2,3-alternate conformation and possesses inversion symmetry. It crystallizes as an acetonitrile disolvate, with a half-mol-ecule of calix[6]arene and one mol-ecule of solvent in the asymmetric unit. In the crystal, the two solvent mol-ecules are enclosed in voids between the calix[6]arene mol-ecules. They form weak C-H⋯O hydrogen bonds involving an O atom of the lower rim substituent. The cavity of the calix[6]arene itself is enclosed by two opposite phenol rings, which are turned into the cavity due to the presence of a C-H⋯π inter-action. The calix[6]arene mol-ecule exhibits disorder of one substituent on its lower rim [occupancy ratio 0.897 (3):0.103 (3)].

10,16-Dichloro-6,20-dioxa-3,23-diaza-tetra-cyclo-[23.3.1.0.0]nona-cosa-1(29),7,9,11,14(19),15,17,25,27-nona-ene-4,22-dione methanol monosolvate.

In the title compound, C(25)H(22)Cl(2)N(2)O(4)·CH(3)OH, the macrocyclic mol-ecule adopts a slightly distorted C(2)-symmetric conformation. The macrocyclic mol-ecules are linked via N-H⋯O hydrogen bonds between the amide groups into chains extending along the [010] direction. The methanol mol-ecules bridge these chains via N-H⋯O and O-H⋯O hydrogen bonds with the formation of a two-dimensional polymeric structure parallel to (001). The methanol mol-ecule is disordered over two positions with the occupancy ratio of 9:1. The disorder of the solvent molecule is caused by weak intermolecular C-H⋯Cl hydrogen bonding.

N,N,N',N'-Tetra-ethyl-pyridine-2,6-dicarboxamide.

The title compound, C(15)H(23)N(3)O(2), crystallizes with two mol-ecules in the asymmetric unit which are linked by a C-H⋯N hydrogen bond. In the crystal, mol-ecules are connected via weak C-H⋯O and C-H⋯N hydrogen bonds between the amide O atoms and ethyl chains and between pyridine N atoms and aromatic H atoms in para positions. C-H⋯π inter-actions also occur.

Tris(2-amino-1,3-thia-zolium) hydrogen sulfate sulfate monohydrate.

The centrosymmetric crystal structure of the novel semi-organic compound, 3C(3)H(5)N(2)S(+)·HSO(4) (-)·SO(4) (2-)·H(2)O, is based on chains of alternating anions and water mol-ecules (formed by O-H⋯O hydrogen bonds). The chains are inter-connected with the 2-amino-1,3-thia-zolium cations via strong N-H⋯O and weak C-H⋯O hydrogen-bonding inter-actions into a three-dimensional network.

Low-temperature superstructure of [(N,N-diisobutyl-carbamo-yl)meth-yl]oct-yl(phen-yl)phosphine oxide (CMPO).

At 120 K, the title compound, C(24)H(42)NO(2)P, crystallizes in a unit cell with a doubled a parameter compared with the room-temperature structure. There are four mol-ecules in the asymmetric unit, one of which shows extensive disorder in a 0.588 (3):0.412 (3) ratio. In the crystal, numerous C-H⋯O inter-actions link the mol-ecules.

2-Amino-1,3-thia-zolium dihydrogen phosphate.

In the title compound, C(3)H(5)N(2)S(+)·H(2)PO(4) (-), the dihydrogen phosphate anions form infinite chains along [001] via short O-H⋯O hydrogen bonds. The 2-amino-thia-zolium cations inter-connect these chains into a three-dimensional network by short linear or bifurcated N-H⋯O and weak C-H⋯O hydrogen bonds.

3,3'-(Ethane-1,2-di-yl)bis-(6-methyl-3,4-dihydro-2H-1,3-benzoxazine).

The asymmetric unit of the title compound, C(20)H(24)N(2)O(2), contains one half-mol-ecule, which is completed by inversion symmetry. In the crystal, mol-ecular chains are formed through non-classical C-H⋯O hydrogen bonds, formed between axial H atoms of the oxazine ring and a O atom of a neighboring mol-ecule.

4,4'-Dichloro-2,2'-[imidazolidine-1,3-diylbis(methylene)]diphenol.

The imidazolidine ring in the title compound, C(17)H(18)Cl(2)N(2)O(2), adopts a twist conformation. The observed conformation is stabilized by two intra-molecular O-H⋯N hydrogen bonds, with both N atoms acting as hydrogen-bond acceptors. The phenyl substituents are aligned at 70.0 (1) and 76.6 (1)° with respect to the best plane through the five atoms of the imidazolidine ring. Weak inter-molecular C-H⋯O inter-actions stabilize the crystal packing.

2-(2-Meth-oxy-phen-yl)-1-benzofuran.

In the title compound, C(15)H(12)O(2), the dihedral angle between the aromatic ring systems is 16.67 (6)°. The methyl C atom is almost coplanar with its attached benzene ring [displacement = 0.020 (2) Å]. In the crystal, the mol-ecules are connected by weak C-H⋯O bonds and face-to-edge C-H⋯π inter-actions between the 2-meth-oxy-phenyl rings.

Bambus[n]urils: a new family of macrocyclic anion receptors.

A recently discovered anion receptor is jointed by three related macrocycles differing in the number of glycoluril units and type of substitution. The synthesis is carried out in nonpolar solvents compared to aqueous media used in the case of the original macrocycle. The size of macrocycle is controlled by a template. A hexameric macrocycle with benzyl substitution binds halide anions with an affinity exceeding 10(9) M(-1) while a tetrameric analog does not bind any of the investigated anions.

5,11,17,23,29-Penta-tert-butyl-31,32,33,34,35-penta-propoxycalix[5]arene dichloro-methane hemisolvate.

The title compound, tert-butyl-propoxycalix[5]arene, C(70)H(100)O(5)·0.5CH(2)Cl(2), crystallizes as a solvate with two mol-ecules of calix[5]arene in 1,2-alternate conformations and one mol-ecule of dichloro-methane in the asymmetric unit. One tert-butyl group in one of the mol-ecules and two in the other are disordered over two positions with occupancy factors fixed at 0.5917:0.4083, 0.5901:0.4099 and 0.8535:0.1465, respectively, in the final refinement. The C atoms of a prop-oxy group in each of the mol-ecules are also disordered over two positions with occupancies of 0.7372:0.2628 and 0.5027:0.4973. The mol-ecules form intra-molecular hydrogen bonds between prop-oxy O atoms and an adjacent CH(2) group in a neighbouring prop-oxy chain. In the crystal, inter-molecular C-H⋯O and C-H⋯Cl inter-actions occur involving the dichloro-methane mol-ecule.

(R)-2,2'-Bis[N'-(3,5-dichloro-phen-yl)ureido]-1,1'-binaphthalene chloro-form disolvate.

The title compound, C(34)H(22)Cl(4)N(4)O(2)·2CHCl(3), is a new urea based on the 1,1'-binaphthalene skeleton, which crystallizes with two mol-ecules of binaphthalene and four mol-ecules of chloro-form in the unit cell. The chloro-form solvent mol-ecules do not participate in non-covalent inter-actions and therefore, can be found in several positions. The binaphthalene mol-ecules are connected via a system of N-H⋯O hydrogen bonds between the ureido units. C-H⋯O inter-actions also occur. In contrast to unsubstituted urea, where mol-ecules form squares in crystals, the bulky substituents disturb this arrangement and three ureido groups form infinite chains, while the fourth inter-acts with a neighbouring binaphthalene ring via an N-H⋯π inter-action. The solvent molecules are disordered with occupancy ratios of 0.60:0.40, 0.58:0.42, 0.50:0.50 and 0.77:0.23.

N,N,N',N'-Tetra-isobutyl-pyridine-2,6-dicarboxamide.

In the title compound, C(23)H(39)N(3)O(2), the amide O atoms are displaced by 1.020 (1) and 1.211 (1) Šfrom the mean plane of the central pyridine ring. In the crystal, mol-ecules are connected by weak C-H⋯O hydrogen bonds between methyl-ene groups in the isobutyl substituents and the amide O atoms.

4,4'-Di-tert-butyl-2,2'-[(3aRS,7aRS)-2,3,3a,4,5,6,7,7a-octa-hydro-1H-1,3-benzimidazole-1,3-di-yl)bis-(methyl-ene)]diphenol.

In the title compound, C(29)H(42)N(2)O(2), the heterocyclic ring has a twist conformation. The cyclohexane ring adopts a chair conformation. The dihedral angle between the aromatic rings is 32.74 (6)°. The mol-ecular conformation is stabilized by two intramolecular O-H⋯N hydrogen bonds with graph-set motif S(6). The crystal packing is stabilized by C-H⋯O and C-H⋯π inter-actions.

1,1'-[(2,3,3a,4,5,6,7,7a-Octa-hydro-1H-1,3-benzimidazole-1,3-di-yl)bis-(methyl-ene)]bis-(1H-benzotriazole).

The cyclo-hexane ring in the title compound, C(21)H(24)N(8), adopts a chair conformation and the five-membered heterocyclic ring to which it is fused adopts a twist conformation on their common C-C bond. The substituents on the N atoms of the central five-membered heterocycle are arranged trans with respect to the central ring. The terminal benzotriazole rings are oriented at angles of 74.66 (8) and 84.18 (8)° with respect to the mean plane of the central heterocycle. The angle between the two benzotriazole rings is 30.80 (9)°. The bond lengths and angles are within normal ranges; the largest deviation from expecta-tion is for a long N-CH(2) bond length [1.476 (2) Å] as a consequence of an anomeric effect. In the crystal, mol-ecules are connected by C-H⋯N hydrogen bonds.

1,4,8,11-Tetra-azoniacyclo-tetradecane diaqua-tetra-chloridomanganese(II) dichloride dihydrate.

The title compound, (C(10)H(28)N(4))[MnCl(4)(H(2)O)(2)]Cl(2)·2H(2)O, consists of isolated octa-hedral [MnCl(4)(H(2)O)(2)](2-) anions, tetra-protonated 1,4,8,11-tetra-azoniacyclo-tetradecane cations, chloride anions and water mol-ecules connected by a network of hydrogen bonds. The Mn(II) atom is situated on an inversion centre, and the 1,4,8,11-tetra-azoniacyclo-tetradecane cation is located on a mirror plane.