Crystalline Ammonium Complexes of Trimethyl- and Triethylbenzene-Based Tripodal Compounds Bearing Pyrazole and Indazole Groups

Crystal structure of the complex of 2,4,6-tri-ethyl-1,3,5-tris-[(4-methyl-1H-indazol-1-yl)meth-yl]-benzene with NH4PF6

The complex of 2,4,6-tri-ethyl-1,3,5-tris-[(4-methyl-1H-indazol-1-yl)meth-yl]-benz-ene with ammonium hexa-fluorophosphate, C₃₉H₄₂N₆·NH₄ ⁺·PF₆ ^-, crystallizes in the monoclinic space group P2₁ with two mol-ecules of the receptor, two NH₄ ⁺ and two PF₆ ^- ions in the asymmetric unit. In each of the complexes the ammonium ion resides in the cavity of the receptor mol-ecule and is fixed in its position by three N-H⋯N bonds, while the remaining hydrogen atom of the cation acts as a bifurcated binding site for N-H⋯F bonding to the counter-anion. The crystal is composed of one-dimensional supra-molecular aggregates extending along the a-axis direction.

Synthesis and crystal structure of 1,3-bis{[N,N-bis(2-hydroxyethyl)amino]methyl}-5-{[(4,6-dimethylpyridin-2-yl)amino]methyl}-2,4,6-triethylbenzene

In the crystal structure of the title compound, C30H50N4O4, the two bis(hydroxyethyl)amino moieties and the 2,4-dimethylpyridinylamino unit of the molecule are located on one side of the central benzene ring, while the ethyl substituents are oriented in the opposite direction. The dihedral angle between the planes of the aromatic rings is 73.6 (1)°. The conformation of the molecule is stabilized by intramolecular O—H...O (1.86–2.12 Å) and C—H...N (2.40, 2.54 Å) hydrogen bonds. Dimers of inversion-related molecules represent the basic supramolecular entities of the crystal structure. They are further connected via O—H...O hydrogen bonding into undulating layers extending parallel to the crystallographic bc plane. Interlayer interaction is accomplished by weak C—H...π contacts.

Co-crystals of tetrahaloauric acid and 1,3,5-(methylacetamide)benzene-based tectons: consistent trapping of high energy molecular conformation

Co-crystal engineering is a promising method to create new classes of advanced materials. Co-crystal structure prediction is more challenging when one or more of the lattice constituents (tectons) are flexible...

Crystal structures of 2-[3,5-bis-(bromo-meth-yl)-2,4,6-tri-ethyl-benz-yl]isoindoline-1,3-dione and 2-{5-(bromo-meth-yl)-3-[(1,3-dioxoisoindolin-2-yl)meth-yl]-2,4,6-tri-ethyl-benz-yl}isoindoline-1,3-dione

The title compounds, C23H25Br2NO2 (1) and C31H29BrN2O4 (2), crystallize in the space group P21/n with two (1-A and 1-B) and one mol-ecules, respectively, in the asymmetric unit of the cell. The mol-ecular conformation of these compounds is stabilized by intra-molecular C-H⋯O hydrogen bonds and C-H⋯N or C-H⋯π inter-actions. The crystal structure of 1 features a relatively strong Br⋯O=C halogen bond, which is not observed in the case of 2. Both crystal structures are characterized by the presence of C-H⋯Br hydrogen bonds and numerous inter-molecular C-H⋯O hydrogen-bonding inter-actions.

Highly Efficient, Tripodal Ion-Pair Receptors for Switching Selectivity between Acetates and Sulfates Using Solid-Liquid and Liquid-Liquid Extractions

A tripodal, squaramide-based ion-pair receptor 1 was synthesized in a modular fashion, and ¹H NMR and UV-vis studies revealed its ability to interact more efficiently with anions with the assistance of cations. The reference tripodal anion receptor 2, lacking a crown ether unit, was found to lose the enhancement in anion binding induced by presence of cations. Besides the ability to bind anions in enhanced manner by the “single armed” ion-pair receptor 3, the lack of multiple and prearranged binding sites resulted in its much lower affinity towards anions than in the case of tripodal receptors. Unlike with receptors 2 or 3, the high affinity of 1 towards salts opens up the possibility of extracting extremely hydrophilic sulfate anions from aqueous to organic phase. The disparity in receptor 1 binding modes towards monovalent anions and divalent sulfates assures its selectivity towards sulfates over other lipophilic salts upon liquid–liquid extraction (LLE) and enables the Hofmeister bias to be overcome. By changing the extraction conditions from LLE to SLE (solid–liquid extraction), a switch of selectivity from sulfates to acetates was achieved. X-ray measurements support the ability of anion binding by cooperation of the arms of receptor 1 together with simultaneous binding of cations.

Syntheses of Acyclic and Macrocyclic Compounds Derived from 9,9-Diethylfluorene (Part I)

A series of new 9,9-diethylfluorenes consisting of three side-arms each bearing a heterocyclic, bis(carboxymethyl)amino, bis(carbamoylmethyl)amino, bis(ethoxycarbonylmethyl)amino or an amino group were prepared on the basis of 2,4,7-tris(bromomethyl)-9,9-diethylfluorene. Imidazolyl, benzimidazolyl, pyrazolyl, pyrrolyl, 1,3-dioxoisoindolyl and pyridinium groups were taken into account as heterocyclic units, attached to the aromatic skeleton via -CH2-, -CH2NHCH2- or -CH2N=CH- linkers. In addition to the seventeen 2,4,7-trisubstituted 9,9-diethylfluorenes, two macrocyclic compounds were prepared on the basis of 2,7-bis(aminomethyl)-9,9-diethylfluorene. The excellent yield of the macrocyclization reaction is worth a special mention. Both the acyclic and the macrocyclic fluorene-based compounds have, among other things, the potential to act as artificial receptors for different substrates in analogy to the known receptors consisting of a benzene or biphenyl core.