First 24-Membered Macrocyclic 1,10-Phenanthroline-2,9-Diamides-An Efficient Switch from Acidic to Alkaline Extraction of -Elements.

A reaction of acyl chlorides derived from 1,10-phenanthroline-2,9-dicarboxylic acids with piperazine allows the preparation of the corresponding 24-membered macrocycles in good yield. The structural and spectral properties of these new macrocyclic ligands were thoroughly investigated, revealing promising coordination properties towards f-elements (Am, Eu). It was shown that the prepared ligands can be used for selective extraction of Am(III) from alkaline-carbonate media in presence of Eu(III) with an SF up to 40.

Pyrrolidine-Derived Phenanthroline Diamides: An Influence of Fluorine Atoms on the Coordination of Lu(III) and Some Other f-Elements and Their Solvent Extraction.

Three pyrrolidine-derived phenanthroline diamides were studied as ligands for lutetium trinitrate. The structural features of the complexes have been studied using various spectral methods and X-ray. The presence of halogen atoms in the structure of phenanthroline ligands has a significant impact on both the coordination number of lutetium and the number of solvate water molecules in the internal coordination sphere.

A Promising 1,3,5-Triazine-Based Anion Exchanger for Perrhenate Binding: Crystal Structures of Its Chloride, Nitrate and Perrhenate Salts.

The reaction of pyridine with cyanuric chloride was studied under microwave activation as well as in the presence of silver nitrate. The product of hydrolysis containing two pyridinium rings and chloride anion was isolated. The structures of these anion exchanger salts with chloride, nitrate and perrhenate anions are discussed.

Competing Routes in the Extraction of Lanthanide Nitrates by 1,10-Phenanthroline-2,9-diamides: An Impact of Structure of Complexes on the Extraction.

The fact of the fracture of the extraction curve of lanthanides by 1,10-phenanthroline-2,9-diamides is explained in terms of the structure of complexes, solvent extraction data and quantum chemical calculations. The solvent extraction proceeds in two competing directions: in the form of neutral complexes Ln(NO) and in the form of tight ion pairs {[Ln(NO) HO] (NO).

Synthesis and crystal structure of a new CuAu-type ternary phase in the Au-In-Pd system: distribution of atoms over crystallographic positions.

A new CuAu-type ternary phase (τ phase) is found in the AuPd-rich part of the Au-In-Pd system. It has a broad homogeneity range based on extensive (Pd,Au) and (In,Au) replacement, with the composition varying between AuInPd and AuInPd. The occupancies of the crystallographic positions were studied by single-crystal X-ray diffraction for three samples of different composition.

Carboxylate-phenolate tautomerism in 5-[(nitrophenyl)diazenyl]salicylate anions.

Aryldiazenyl derivatives of salicylic acid and their salts are used as dyes. In these structures, the carboxylate groups are engaged in short contacts with the cations and in hydrogen bonds with water molecules, if present. If both O atoms of the carboxylate group take part in such interactions, the negative charge is delocalized over the two atoms.

syn and anti conformations in 2-hydroxy-5-[(E)-(4-nitrophenyl)diazenyl]benzoic acid and two related salts.

The crystal structures of 2-hydroxy-5-[(E)-(4-nitrophenyl)diazenyl]benzoic acid, C13H9N3O5, (I), ammonium 2-hydroxy-5-[(E)-phenyldiazenyl]benzoate, NH4(+)·C13H9N2O3(-), (II), and sodium 2-hydroxy-5-[(E)-(4-nitrophenyl)diazenyl]benzoate trihydrate, Na(+)·C13H8N3O5(-)·3H2O, (III), have been determined using single-crystal X-ray diffraction. In (I) and (III), the phenyldiazenyl and carboxylic acid/carboxylate groups are in an anti orientation with respect to each other, which is in accord with the results of density functional theory (DFT) calculations, whereas in (II), the anion adopts a syn conformation. In (I), molecules form slanted stacks along the [100] direction.

4-[(E)-1-Naphthyl-diazen-yl]phenol.

The title compound (C. I. Solvent Yellow 8), C(16)H(12)N(2)O, crystallizes with two crystallographically independent mol-ecules in the asymmetric unit.

4-Chloro-2-[(E)-(4-nitro-phen-yl)diazenyl]phenol.

The title compound, C(12)H(8)ClN(3)O(3), in the crystalline state and in solution, exists in the azo form, as predicted by density functional theory (DFT) calculations. The mol-ecule is approximately planar [the dihedral angle between the rings is 1.83 (8)°], with the nitro group slightly twisted [13.

Structural characterization of prazosin hydrochloride and prazosin free base.

The three-dimensional solid-state structures of prazosin hydrochloride, C19H22N5O4+.Cl- (A), and prazosin free base, C19H21N5O4 (B), have been determined by synchrotron X-ray powder diffraction. A and B crystallize in triclinic P-1 and monoclinic Cc space groups, respectively, with one structural unit per asymmetric part.

Protonation site and hydrogen bonding in anhydrous and hydrated crystalline forms of doxazosin mesylate from powder data.

The three-dimensional solid-state structures of two modifications of doxazosin mesylate (C23H26N5O5)+.(CH3SO3)-, 4-amino-2-[4-[(2,3-dihydro-1,4-benzodioxin-2-yl)carbonyl]piperazin-1-yl]-6,7-dimethoxyquinazoline methanesulfonate, a commonly used antihypertensive agent, have been determined by synchrotron X-ray powder diffraction. An anhydrous form (A) and a dihydrate form (dG) crystallize in monoclinic space groups.

Molecular crystals: the crystal field effect on molecular electronic structure.

The effect of crystal packing on the electronic structure of organic molecules was modeled by incorporation of the external electrostatic potential into the semiempirical Hamiltonian of the molecule. An empirical correction procedure was devised in order to compensate for systematic errors in the charge distribution typical of semiempirical methods. The model was applied to 79 crystal structures belonging to various syngonies and space groups.