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L-phenylalanine methyl ester derivative of dexamethasone - derived cortienic acid (DF) was synthesized and its crystal structure was characterized by X-ray diffraction method. The crystal system is orthorhombic with space group P212121 and cell constants a = 8.2969 (3) Å, b = 18.9358 (8) Å, c = 20.0904 (6) Å, V = 3156.4 (2) Å3 and Z = 4. Ring A of the steroid nucleus and phenyl ring in the 17β-side chain are almost planar. Rings B and C have a slightly distorted chair conformation, whereas ring D has an envelope conformation. The packing of DF is characterized by a network of intermolecular hydrogen bonds involving the O4 atom from one side of the steroid nucleus and O1 and F1 atoms from the other side as hydrogen bond acceptors. Apart from the intermolecular hydrogen bonds in the crystal packing, there are also numerous intramolecular hydrogen bonds of the N-H...O, C-H...O and C-H...F type. Local anti-inflammatory activity of DF was evaluated by use of croton oil-induced ear edema test. This derivative achieved maximal inhibition of ear edema at significantly lower concentration in comparison with dexamethasone. [Projekat Ministarstva nauke Republike Srbije, br. 172041, 172014 i 172035]

Charge density distribution in 2-pyridineformamide N(4)-methylthiosemicarbazone (TSC4) has been determined using high-resolution X-ray diffraction data (100 K) and Hansen-Coppens multipole formalism. The results are interpreted in terms of Bader's quantum theory of atoms in molecules (QTAIM), electrostatic potential analysis, and theoretical calculations (CRYSTAL09). The study highlights the molecular dissimilarity at the electronic level. The N-H···S interactions have a dominant role in stabilization of the TSC4 crystal structure. As each of the four S acceptors simultaneously engages in several interactions, the focus of study is on the lone pairs' electron density of these acceptors which is particularly able to adjust to the various spatial distributions of the interacting donor groups. The main structural feature of TSC4 is the formation of specific N-H···S bonded dimers between two pairs of independent molecules. These dimers are the main building block in the crystal structure, and with the two additional N-H···S contacts they represent a significant enhancement of a typical R²2(8) dimer synthon which dominates among the thioureido-based crystal structures. Two TSC4 dimers are structurally very similar and exhibit considerable cohesive energy (-20.8 and -21.4 kcal/mol). This type of dimer is the only structural motif that is common for S acceptors of all four independent molecules. [ABSTRACT FROM AUTHOR]

In the title compound, [Fe(C8H7N3)(H2O)4]SO4, the central Fe(II) ion is octa-hedrally coordinated by two N atoms from the bidentate 2-(pyridin-2-yl)-1H-imidazole ligand and by four O atoms of the aqua ligands. The largest deviation from the ideal octa-hedral geometry is reflected by the small N-Fe-N bite angle of 76.0 (1)°. The Fe-N coordination bonds have markedly different lengths [2.1361 (17) and 2.243 (2) Å], with the shorter one to the pyrimidine N atom. The four Fe-O coordination bond lengths vary from 2.1191 (18) to 2.1340 (17) Å. In the crystal, the cations and anions are arranged by means of medium-strength O-H⋯O hydrogen bonds into layers parallel to the ab plane. Neighbouring layers further inter-connect by N-H⋯O hydrogen bonds involving the imidazole fragment as donor group to one sulfate O atom as an acceptor. The resulting three-dimensional network is consolidated by C-H⋯O, C-H⋯π and π-π inter-actions.

In the title compound, [Fe(C12H12N2)(H2O)4]SO4, the central Fe(II) ion is coordinated by two N atoms from the 5,5'-dimethyl-2,2'-bi-pyridine ligand and four water O atoms in a distorted octa-hedral geometry. The Fe-O coordination bond lengths vary from 2.080 (3) to 2.110 (3) Å, while the two Fe-N coordination bonds have practically identical lengths [2.175 (3) and 2.177 (3) Å]. The chelating N-Fe-N angle of 75.6 (1)° shows the largest deviation from an ideal octa-hedral geometry; the other coordination angles deviate from ideal values by 0.1 (1) to 9.1 (1)°. O-H⋯O hydrogen bonding between the four aqua ligands of the cationic complex and four O-atom acceptors of the anion leads to the formation of layers parallel to the ab plane. Neighbouring layers further inter-act by means of C-H⋯O and π-π inter-actions involving the laterally positioned bi-pyridine rings. The perpen-dicular distance between π-π inter-acting rings is 3.365 (2) Å, with a centroid-centroid distance of 3.702 (3) Å.

In the title compound, C(16)H(11)F(3)O(2), the γ-pyran-one ring adopts an envelope conformation with the chiral C atom standing out of the ring plane. In the crystal, molecules are linked by C-H⋯O and C-H⋯F inter-actions.