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POCOP-Ni(II) pincer compounds have primarily been explored as catalysts, but their potential biological activity has been scarcely studied. To address this gap, we evaluated the anticancer and antioxidant potential of four POCOP-Ni(II) complexes derived from phloroglucinol. A comprehensive supramolecular analysis, based on single-crystal X-ray diffraction (DRX) structures, was conducted using Hirshfeld surfaces and non-covalent interaction analysis. The cytotoxicity of all complexes was systematically assessed against various cancerous cell lines, as well as a non-cancerous cell line (COS-7). The results revealed that complexes 1b and 1c exhibited remarkable antiproliferative activity, with IC50 values ranging from 2.43 to 7.85 μM against cancerous cell lines U251, K562, HCT-15, MCF-7, and SK-LU-1. To further elucidate their mechanism of action, a competitive fluorescence displacement assay with ethidium bromide (EB) suggested that these complexes possess the ability to intercalate with DNA. This multifaceted investigation not only enhances our understanding of the biological potential of POCOP-Ni complexes but also provides valuable insights into their structural features and interactions, paving the way for future exploration in both catalytic and therapeutic domains.

The molecular structure of 2-ferrocenyl-2-[(2-ferrocenylethenyl)(morpholin-4-yl)methyl]-1,3-dithiolane, [Fe2(C5H5)2(C19H21NOS2)] or C29H31Fe2NOS2, has the ferrocenyl fragments in a trans disposition with respect to the vinyl group. One of the methylene groups is disordered over two sites with occupancies of 0.782 (13):0.218 (13). In the crystal, cyclopentadienyl-C—H...O(morpholinyl) interactions feature within helical chains parallel to the c-axis direction. The chains are connected by methylene- and cyclopentadienyl-C—H...O(cyclopentadienyl) interactions.

The structure of the title Fe complex, [Fe(C5H5)2(C17H16N4O)], was determined at 130 K, and has orthorhombic (Pna21) symmetry. It is of interest with respect to the class of triazine heterocyclic compounds: the triazine ring is substituted by two ferrocenyl and one morpholine groups. The crystal structure features C—H...O and C—H...N non-classical hydrogen bonds.

The structure of 4,5-diferrocenyl-1,2-dithiole-3-thione, [Fe2(C5H5)2(C13H8S3)] or C23H18Fe2S3, at 130 K has monoclinic (P21/c) symmetry. The molecule has two ferrocenyl units attached to a 1,2-dithiole-3-thione moiety. It is of interest with respect to the question if the introduction of ferrocenyl substituents into biologically active molecules offers the potential to obtain more efficacious therapeutic drugs. The crystal structure displays intermolecular contacts of the C—H...S and S—π(C—C) types.

The molecular structure of the title complex, [Ni(C13H8F2N2O)(C14H32P2)] or Ni(oFPU)(dippe), where oFPU is the dianion of bis(2-fluorophenyl)urea and dippe is 1,2-bis(di-isopropylphosphino)ethane, comprises an NiII atom with a distorted square-planar coordination environment (geometry index τ4 = 0.195). One of the fluorophenyl rings of the oFPU ligand is disordered over two sets of sites in an 0.832 (7):0.168 (7) ratio. The crystal structure displays C—H...O and C—H...F hydrogen-bonding interactions, leading to chains with R22(12) motifs extending parallel to [100]. The title compound might be of interest with respect to the production of urea and carbamate derivatives of nickel(II).

Two new glycine-Schiff base copper(II) complexes were synthesized. Single crystal X-ray diffraction (SCXRD) allowed us to establish the structure of both complexes in the solid state. The glycine-Schiff base copper(II) complex derived from 2′-hydroxy-5′-nitroacetophenone showed a mononuclear hydrated structure, in which the Schiff base acted as a tridentate ligand, and the glycine-Schiff base copper(II) complex derived from 2′-hydroxy-5′-methylacetophenone showed a less common tetranuclear anhydrous metallocyclic structure, in which the Schiff base acted as a tetradentate ligand. In both compounds, copper(II) had a tetracoordinated square planar geometry. The results of vibrational, electronic, and paramagnetic spectroscopies, as well as thermal analysis, were consistent with the crystal structures. Both complexes were evaluated as catalysts in the olefin cyclopropanation by carbene transference, and both led to very high diastereoselectivity (greater than 98%).

The asymmetric unit of the title compound, [Fe(C5H5)(C12H7ClNO)], consists of one ferrocenyl group bonded to chlorobenzo[d]oxazole. The conformation of the ferrocenyl moiety is slightly away from eclipsed. The bond angles between the 5-chloro-benzoxazole and ferrocenyl fragments are N—C—C = 127.4 (7)° and O—C—C = 116.8 (7)°. The benzo[d]oxazole ring is planar (r.m.s. deviation = 0.0042 Å) and makes an angle of 11.3 (4)° with the cyclopentadienyl ring attached to it. The crystal packing is characterized by intermolecular π–π contacts, resulting in chain formation along the b-axis direction. The centroid-to-centroid distance between the six- and five-membered rings is 3.650 (5) Å. Together with a C—H...π interaction, these intermolecular contacts form laminar arrays along the ac plane.

In total, 13 ligands R-salen (N,N’-bis(5-R-salicylidene)ethylenediamine (where R = MeO, Me, OH, H, Cl, Br, NO2) and R-salphen (N,N’-bis(5-R-salicylidene)-1,2-phenylenediamine (where R = MeO, Me, OH, H, Cl, Br) and their 13 nickel complexes NiRsalen and NiRsalphen were synthesized and characterized using IR (infrared) spectroscopy, mass spectrometry, elemental analysis, magnetic susceptibility, NMR (nuclear magnetic resonance), UV-vis (ultraviolet-visible) spectroscopy, cyclic voltammetry, and X-ray crystal diffraction. Previous studies have shown that all complexes have presented a square planar geometry in a solid state and as a solution (DMSO). In electrochemical studies, it was observed that in N/N aliphatic bridge complexes, the NiII underwent two redox reactions, which were quasi-reversible process, and the half-wave potential followed a trend depending on the ligand substituent in the 5,5’-R position. The electron-donor substituent—as -OH, and -CH3 decreased the E1/2 potential—favored the reductor ability of nickel. The crystals of the complexes NiMesalen, NiMeOsalen, NiMeOsalphen, and Nisalphen were obtained. It was shown that the crystal packaging corresponded to monoclinic systems in the first three cases, as well as the triclinic for Nisalphen. The Hirshfeld surface analysis showed that the packaging was favored by H∙∙∙H and C∙∙∙H/H∙∙∙C interactions, and C-H∙∙∙O hydrogen bridges when the substituent was -MeO and π-stacking was added to an aromatic bridge. Replacing the N/N bridge with an aromatic ring decreased distortion in square-planar geometry where the angles O-Ni-N formed a perfect square-planar.

Isoniazid is used as anti-tuberculosis drug which possesses functional groups capable of forming hydrogen bonds. A series of cocrystals of isoniazid (INH) with polyphenolic coformers such as catechol (CAT), orcinol (ORC), 2-methylresorcinol (MER), pyrogallol (PYR), and phloroglucinol (PLG) were prepared by solvent-assisted grinding. Powder cocrystals were characterized by infrared (IR) spectroscopy and X-ray powder diffraction. The crystal structure of the cocrystals revealed the unexpected hydration of the INH-MER cocrystal and the preference of the (phenol) O–H∙∙∙N (pyridine) and (terminal) N-H∙∙∙O (phenol) heterosynthons in the stabilization of the structures. The supramolecular architecture of the cocrystals is affected by the conformation and the substitution pattern of the hydroxyl groups of the polyphenols.

The title compound, [Fe2(C5H5)2(C13H8OS2)], crystallizes with two molecules in the asymmetric unit. Each molecule comprises a pair of ferrocenyl units bridged by a dithiol-3-one moiety. The dihedral angles between the dithiol-3-one ring and the substituted cyclopentadienyl rings are in the range 32.4 (3)–39.3 (3)°. One of the dithiol-3-one rings was refined as being disordered over two sets of sites while the same kind of disorder in the other molecule was negligible. The molecular packing is dominated by C—H...O hydrogen bonds and C—H...π interactions.

Four new hydrazones were synthesized by the condensation of the selected hydrazine and the appropriate nitrobenzaldehyde. A complete characterization was done employing 1H- and 13C-NMR, electrochemical techniques and theoretical studies. After the characterization and electrochemical analysis of each compound, amoebicidal activity was tested in vitro against the HM1:IMSS strain of Entamoeba histolytica. The results showed the influence of the nitrobenzene group and the hydrazone linkage on the amoebicidal activity. meta-Nitro substituted compound 2 presents a promising amoebicidal activity with an IC50 = 0.84 μM, which represents a 7-fold increase in cell growth inhibition potency with respect to metronidazole (IC50 = 6.3 μM). Compounds 1, 3, and 4 show decreased amoebicidal activity, with IC50 values of 7, 75 and 23 µM, respectively, as a function of the nitro group position on the aromatic ring. The observed differences in the biological activity could be explained not only by the redox potential of the molecules, but also by their capacity to participate in the formation of intra- and intermolecular hydrogen bonds. Redox potentials as well as the amoebicidal activity can be described with parameters obtained from the DFT analysis.

The title chalcone derivative, C13H10O2, adopts an E conformation about the C=C double bond. The molecule is composed of a furanyl and a phenyl ring, bridged by an α,β-unsaturated carbonyl system, which are inclined to one another by 24.07 (7)°. In the crystal, molecules are connected by weak C—H...O hydrogen bonds involving the carbonyl O atom acting as a trifurcated acceptor and C—H...π interactions, forming ribbons extending along the c-axis direction.

In the title compound, [Ru2(C5H5)2(C13H8O)], the Ru—C bond lengths in the two ruthenocenyl moieties are in the range of 2.155 (4)–2.196 (3) Å. Both cyclopentadienyl (Cp) rings are planar and parallel with staggered (18.6 °) and eclipsed (3.1°) conformations between the mutual orientations of rings in the independent sandwiches of each ruthenocenyl molecule. In the crystal, there are intermolecular C—H...O hydrogen bonds between Cp carbon donor atoms and the cyclopropenone O atom of adjacent molecules, forming R22(14) and R66(38) motifs along the b and c axes.

Acetamidine hydrochloride and p-aminobenzamidine dihydrochloride interact with 3-ferrocenylmethylidene-2,4-pentanedione at 80–82 °C in the presence of K2CO3 in the water–alcohol medium in two tautomeric forms (the amidoimine and enediamine ones) with formation of mixtures of pyrimidine and piperidone derivatives and polymeric coordination complexes of potassium ferrocenyl(hexahydro)pyrimidoxides. The structure of the resultant compounds is elucidated on the basis of IR, 1H- and 13C-NMR spectroscopy, mass spectrometry and elemental analysis data. The crystal structures of 6-ferrocenyl-4-hydroxy-4-methyl-2-piperidone, potassium 6-ferrocenyl-4-methyl-2-methylidene(hexahydro)pyrimidin-4-oxide and 2-(4-aminophenyl)-4-ferrocenyl-6-methyl-pyrimidine were determined by X-ray analysis of suitable single crystals.

Six new fluorinated thiosemicarbazones R‑C(R′)=N-NH-C(S)NH2 (R = 2,4-C6H3F2, R′ = H (1); R = 2,5-C6H3F2, R′ = H (2); R = 2,6-C6H3F2, R′ = H (3); R = 3,4-C6H3F2, R′ = H (4); R = 3,5-C6H3F2, R′ = H (5) and R = 4-C6H4F, R′ = C6H5, (6)) have been prepared. The molecular structures of compounds 1 to 6 have been determined.

In the title compound, [ZnBr3(C4H12N5)], the ZnII cation is tetrahedrally coordinated by three bromide ions and the (N-{amino[(diaminomethylene)amino]methylene}-N-methylmethanaminium) cation that binds through the central N atom. The complex is of interest as a potential antidiabetic drug of the biguanide family. The crystal structure is stabilized by an extensive series of N—H...Br and C—H...Br hydrogen bonds, which combine to form a three-dimensional structure.

The reactions of 2-cyano-3-ferrocenylacrylonitrile (1) with malononitrile (2) in a MeOH/H2O or 2-PrOH/H2O medium in the presence of Na2CO3 afforded 6-alkoxy-2-amino-4-ferrocenylpyridine-3,5-dicarbonitriles 3a,b (multi-component condensation) and 6-alkoxy-2-amino-4-ferrocenyl-3-ferrocenylmethyl-3,4-dihydropyridine-3,5-dicarbonitriles 4a,b (multi-component cyclodimerization). Analogous reactions of 1 with 2 in an MeOH/H2O medium in the presence of NaOH, piperidine, or morpholine gave compounds 3a, 4a and 2-amino-4-ferrocenyl-6-hydroxy-, 6-piperidino- and 6-morpholinopyridine-3,5-dicarbonitriles 3c–e, respectively. The structures of the compounds 3b, 4a and 4b were established by the spectroscopic data and X-ray diffraction analysis. The electrochemical behaviour of compounds 3b, 3d and 4b was investigated by means of cyclic voltammetry.

Synthesis of 3,4-diferrocenyltoluene (7), 1-morpholino- and 1-piperidino-2,3-diferrocenylbicyclo[3.1.0]hex-2-enes 8a, 8b, 1-morpholino- and 1-piperidino-7-ferrocenyl-3,4-ferrocenobicyclo[3.2.1]oct-6-enes 9a, 9b, 2- and 3-amino(diferrocenyl)-hexa-1,3,5-trienes 10a,b, 11a,b by reactions of amino(diferrocenyl)cyclopropenylium tetrafluoro-borates with 1-methylprop-2-enylmagnesium chloride at 80 °C is described. The structures of the compounds obtained were determined by IR, 1H- and 13C-NMR spectroscopy and mass spectrometry. X-ray diffraction data for 1-piperidino-7-ferrocenyl-3,4-ferroceno-bicyclo[3.2.1]oct-6-ene (9b), 2-morpholino- and 2-piperidino-1,3-diferrocenyl-4-methyl-hexa-1,3,5-trienes 10a and 10b is presented. The electrochemical behaviour of compounds 7, 8a, 10a and 10b was investigated by means of cyclic voltammetry and square wave voltammetry. For 7 and 8a two electrochemical processes (I-II), attributed to the oxidation of the ferrocene moieties were found. On the other hand for compounds 10a and 10b a single electron transfer for both ferrocene groups and the electrochemical generation of the monocation and dication species were detected.

3-Cyanoamino-1,2- and -2,3-diferrocenylcyclopropenes 6a,b and 11a,b prepared by the reaction of diferrocenylcyclopropenylium salts with sodium cyanamide undergo smooth intramolecular transformations with both conservation of the three-membered ring [affording 3-cyanoimino-1,2-diferrocenylcyclopropene (8)] and its opening [affording Z-3-morpholino- and Z-3-piperidino-3-(cyanoimino)-1,2-diferrocenylprop-1-enes 7a,b and Z-3-cyanoimino-2,3-diferrocenyl-1-methylthioprop-1-ene (10)]. 3-Cyano-imino-1,2-diferrocenylcyclopropene (8) reacts with hydrazine to form 3-amino-6-ferrocenyl-5-ferrocenylmethyl-1,2,4-triazine (12) and Z-2,3-diferrocenylacrylohydrazide N-cyanoimide (13) as a result of intramolecular transformations. The structures of the compounds obtained were determined by IR, 1H- and 13C-NMR spectroscopy and mass spectrometry. The structures of compounds 7a and 10 were additionally confirmed by their X-ray diffraction analysis data.

In the cation of the title salt, C18H20N3+·I−, the mesityl and phenyl rings are inclined to the central triazolium ring by 61.39 (16) and 30.99 (16)°, respectively, and to one another by 37.75 (15)°. In the crystal, molecules are linked via C—H...I hydrogen bonds, forming slabs parallel to the ab plane. Within the slabs there are weak π–π interactions present involving the mesityl and phenyl rings [inter-centroid distances are 3.8663 (18) and 3.8141 (18) Å].

The molecular conformation of the title compound, C14H18N2O3S2, is stabilized by intramolecular N—H...N and C—H...O hydrogen bonds. The crystal packing is characterized by a series of C—H...O hydrogen bonds, resulting in a three-dimensional network.

The title compound, C19H15N3O2, shows an E conformation of the imine bond. The dihedral angle between the planes of the phenyl rings in the diphenylhydrazine groups is 88.52 (4)°. The 2-nitrobenzene ring shows a torsion angle of 10.17 (8)° with the C=N—N plane. A short intramolecular C—H...O contact occurs. In the crystal, only van der Waals contacts occur between the molecules.

The asymmetric unit of the title compound, C19H23FN3O3+·Cl−·2H2O [systematic name: 4-(3-carboxy-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinolin-7-yl)-1-ethylpiperazin-1-ium chloride dihydrate], consists of two independent monocations of the protonated enrofloxacin, two chloride anions and four water molecules. In the cations, the piperazinium rings adopt chair conformations and the dihedral angles between the cyclopropyl ring and the 10-membered quinoline ring system are 56.55 (2) and 51.11 (2)°. An intramolecular O—H...O hydrogen bond is observed in each cation. In the crystal, the components are connected via O—H...Cl, N—H...Cl and O—H...O hydrogen bonds, and a π–π interaction between the benzene rings [centroid–centroid distance = 3.6726 (13) Å], resulting in a three-dimensional array.

In the title compound, C18H13ClN2OS·CH3OH, the dihedral angle between the benzimidazole group and the naphthyloxy moiety [82.89 (5)°] very near to orthogonality. The H atom in the five-membered ring is disordered with equal occupancies at the two N atoms and the H atom of the methanolic hydroxy group is disordered with equal occupancies over two sites at the O atom. The methanol molecule acts as a hydrogen-bond acceptor for the amino H atom and donates a hydrogen bond to the nonprotonated ring N atom. As a result, chains are formed running along the a axis.

The asymmetric unit of the title compound, C17H14N2S, consists of two crystallographically independent molecules with similar conformations. The dihedral angles between the phenyl rings are 89.32 (5) and 82.80 (5)° in the two molecules. In the crystal, molecules are linked by C—H...π interactions, forming a three-dimensional network.

The title compound, C16H15NO3, consists of an oxabicycle fused to an N-phenyl-substituted pyrrolidine ring anti to the double bond, affording the exo isomer. In the oxabicycle system, the six-membered ring presents a boat conformation, while the heterocyclic rings show envelope conformations with the O atom projected out of the plane. In the crystal, adjacent molecules are linked via weak C—H...O hydrogen bonds, forming chains propagating along the a-axis direction. The chains are linked by C—H...π interactions, forming two-dimensional networks lying parallel to the ac plane.

In the crystal of the title compound, C19H14N4O4, the asymmetric unit consists of two discrete molecules. The C=N bonds in both molecules show an E conformation. The dihedral angles between the C atoms of the 2,4-dinitrobenzene rings and the C=N—N planes are 13.52 (9) and 13.82 (9)° for the two molecules. In the crystal, C—H...O hydrogen bonds, mainly between the phenyl ring and the nitro group along the b axis.

In the crystal of the title compound, [Ni(CO3)(C14H32P2)], the metal center in each of three independent molecules shows slight tetrahedral distortion from ideal square-planar coordination geometry, with angles between the normals to the planes defined by the cis-P—Ni—P and cis-O—Ni—O fragments of 3.92 (17), 0.70 (16) and 2.17 (14)° in the three molecules. In the crystal, there are intermolecular C—H...O hydrogen bonds that show a laminar growth in the ab plane.

The title compound, C12H10N2O, a second monoclinic polymorph of (E)-phenyl(pyridin-2-yl)methanone oxime crystallizes in the space group P21/n (Z = 4). The previously reported polymorph [Taga et al. (1990). Acta Cryst. C46, 2241–2243] occurs in the space group C2/c (Z = 8). In the crystal, pairs of bifurcated O—H...(N,O) hydrogen bonds link the molecules into inversion dimers. The dimers are linked by C—H...π interactions, forming a linear arrangement. The dihedral angle between the pyridine and phenyl rings is 67.70 (8)°.

In the title compound, C23H17N3O3, the terminal benzene rings are oriented at dihedral angles of 3.67 (7), 76.02 (7) and 16.37 (7)° with respect to the central furan ring. In the crystal, molecules are connected via weak C—H...O hydrogen bonds, resulting in a three-dimensional supramolecular array.

The title molecule, C18H20O3, is a furanoid lignan extracted from the leaves of Larrea tridentata. The relative absolute configuration for the four chiral centers was established, showing that this compound is 4-epi-larreatricin, which has been previously reported in the literature. The molecule displays noncrystallographic C2 symmetry, with the methyl and phenol substituents alternating above and below the mean plane of the furan ring. The conformation of this ring is described by the pseudorotation phase angle P = 171.3° and the maximum out-of-plane pucker νm = 37.7°. These parameters indicate that the furan ring adopts the same conformation as the ribose residues in B-DNA. The packing is dominated by intermolecular O—H...O hydrogen bonds. The phenol hydroxy groups form chains in the [110] direction and these chains interact via O—H...O(furan) contacts.

The title compound, [Dy(NO3)3(C21H17NO4)(H2O)2]·C21H17NO4, may be considered as an organic–metalorganic 1:1 co-crystal, in which the two dialdehyde molecules act as a ligand and as an organic moiety, respectively. The DyIII atom coordinates nine O atoms from the organic ligand, bidentate nitrate ions and water molecules, approximating a square-face-tricapped trigonal–prismatic geometry. The coordinated dialdehyde is not planar: the uncoordinated oxybenzaldehyde group is twisted by 39.96 (4)° from the rest of the ligand. In contrast, the free organic moiety is almost planar, with an r.m.s. deviation of 0.15 Å. In the crystal, segregated stacks of dialdehyde are formed in the [100] direction. For the complex, the shortest π–π contact is found at 3.781 (2) Å, and for the free ligand, at 3.785 (2) Å. The crystal structure is further stabilized by O—H...O and O—H...N hydrogen bonds in which coordinated water molecules are the donor groups.

Diosgenin [or (22R,25R)-spirost-5-en-3β-ol] is the starting material of the Marker degradation, a cheap semi-synthesis of progesterone, which has been designated as an International Historic Chemical Landmark. Thus far, a single X-ray structure for diosgenin is known, namely its dimethyl sulfoxide solvate [Zhang et al. (2005). Acta Cryst. E61, o2324–o2325]. We have now determined the structure of the hemihydrate, C27H42O3·0.5H2O. The asymmetric unit contains two diosgenin molecules, with quite similar conformations, and one water molecule. Hydroxy groups in steroids and water molecules form O—H...O hydrogen-bonded R54(10) ring motifs. Fused edge-sharing R(10) rings form a backbone oriented along [100], which aggregates the diosgenin molecules in the crystal structure.

Diosgenone [(20S,22R,25R)-spirost-4-en-3-one, C27H40O3] has been proposed as a new therapeutic alternative for the treatment of malaria. The first X-ray structure report for diosgenone was by Piro et al. [(2002). Z. Naturforsch. Teil C, 57, 947–950] in the space group P21 (Z′ = 2). We now report a new polymorph in the same space group, with two molecules in the asymmetric unit. Both molecules have similar conformations, characterized by a skewed envelope A ring, which contains the C=C bond conjugated with the ketone functionality at C3. The dimorphism results from a modification of the relative orientation of the molecules in the asymmetric unit: two independent molecules were arranged antiparallel in the Piro report, while they are parallel in the present determination.

In the title compound C17H25NO2, the piperidin-2-one ring adopts an envelope conformation with the C atom in the 5-position as the flap. The crystal packing is stabilized by intermolecular O—H...O hydrogen bonds, building a infinite chain along the b-axis direction. C—H...π interactions further stabilize the crystal packing.

In the title compound, [Cu(C14H12N2)3](PF6)2·CH3CN, the [Cu(5,6-dmp)3]2+ cationic complex (5,6-dmp is 5,6-dimethyl-1,10-phenanthroline) is stabilized by two hexafluoridophosphate anions and one acetonitrile solvent molecule. The coordination geometry around the CuII atom can be described as distorted elongated octahedral with Rout = 2.277 (2) Å, Rin = 2.052 (2) Å and a tetragonality of 0.9011, acquiring a `static' stereochemistry. In the supramolecular network, there are intermolecular C—H...F and C—H...N interactions with R33(16), R22(7), R12(4), R33(16) and C32(7) motifs that lead to an infinite three-dimensional network.

The title tertiary amine, C27H27N7, a potential tripodal ligand for coordination chemistry, crystallizes with the central N atom located on a threefold axis of a trigonal cell. The gauche conformation of the N(amime)—CH2—CH2—N(indazole) chain [torsion angle = −64.2 (2)°] places the pendant 2H-indazole heterocycles surrounding the symmetry axis, affording a claw-like shaped molecule. Two symmetry-related indazole planes in the molecule make an acute angle of 60.39 (4)°. The lone pair of the tertiary N atom is located inside the cavity, and should thus be inactive (as a ligand). In the crystal, neither significant π–π nor C—H...π interactions between molecules are found.

In the zwitterionic title compound, C9H13NO2S, the pyrrolidine heterocycle adopts an envelope conformation (with the C atom in the 7-position as the flap). The negative charge is delocalized over the two carbonyl groups and the C atom connecting them. The positive charge is located on the S atom. Two intermolecular C—H...O interactions are observed. The molecular geometry at the S atom is trigonal pyramidal.

In the title compound, [Cu(C16H20N2S2)(H2O)](NO3)2·CH3CN, the CuII atom displays a distorted square-pyramidal coordination, in which a water molecule occupies the apical position and the basal plane is formed by two N atoms and two S atoms of a 1,8-bis(pyridin-2-yl)-3,6-dithiaoctane ligand. The crystal packing is stabilized by O—H...O and C—H...O hydrogen bonds.

In the title compound, [Cu(C5H10NO2)(C12H8N2)(H2O)]NO3·2H2O, the CuII atom displays a distorted square-pyramidal coordination (τ = 0.03) where the water molecule occupies the apical position and the base is defined by the N atom, one of the O atoms from the valinate ligand, and both phenanthroline N atoms. The phenanthroline chelate ring plane is slightly distorted from planarity (r.m.s. deviation = 0.0057 Å), whereas the five-membered ring formed by the valinate ligand presents an envelope conformation with the N atom being the flap atom. The crystal packing is stabilized by O—H...O and N—H...O hydrogen-bonding interactions, creating a three-dimensional network superstructure.

In the crystal structure of title compound, [NiCl2(C14H32P2)], the NiII atom lies on a twofold rotation axis and shows a slightly distorted square-planar coordination geometry, with a dihedral angle of 10.01 (8)° between the cis-Cl—Ni—Cl and cis-P—Ni—P planes. There is no significant intermolecular interaction except very weak C—H...Cl interactions. The crystal studied was a racemic twin.

The title compound, C24H24N2, is an enantiomerically pure bis-aldimine, which displays twofold crystallographic symmetry, with two C atoms of the central benzene ring lying on the symmetry axis. The imine group is slightly twisted from the benzene core, with a dihedral angle of 12.72 (16)° between the benzene ring and the C=N—C* plane. The terminal phenyl rings make an angle of 66.44 (4)° and are oriented in opposite directions with respect to the benzene ring. In the crystal, molecules interact weakly through a C—H...π interaction involving the phenyl rings, and form chains along the 21 screw-axis in the [100] direction.

The asymmetric unit of the title compound, C21H20N2, contain two molecules, both of them showing an E configuration of the C=N bond. The dihedral angles between the phenyl rings in the phenylhydrazone groups are 86.84 (10) and 84.85 (8)° for the two molecules. Intermolecular C—H...π interactions are observed in the crystal structure.

In the title compound, [NiCl2(C14H32P2)]·2C12H9N, the neutral [Ni(dppe)Cl2] complex [dppe is 1,2-bis(diisopropylphosphanyl)ethane] consists of a tetracoordinated Ni2+ cation and has a crystallographic twofold axis passing through the metal atom and the mid-point of the CH2—CH2 bond of the dppe ligand. The metal atom shows slight tetrahedral distortion from an ideal square-planar coordination geometry, as reflected in the dihedral angle between NiCl2 and NiP2 planes of 15.32 (2)°. The 9H-carbazole ring system is essentially planar (r.m.s. deviation = 0.022 Å). In the crystal packing, there are two symmetry-related 9H-carbazole molecules between two adjacent NiII complexes, with an angle between the carbazole mean planes of ca 77°.

In the title compound {systematic name: 2-[(E)-but-2-en-1-yl]isoindoline-1,3-dione}, C12H11NO2, the phthalimide ring system is essentially planar, with a maximum deviation of 0.008 (1) Å, while the plane of the N-crotyl substituent is orthogonal to the phthalimide ring system, making a dihedral angle of 87.5 (1)°.

In the crystal structure of the title compound, C26H22N4, the molecule is located on an inversion centre and shows an E configuration with respect to each C=N bond. The dihedral angle between the phenyl rings in the diphenylhydrazone group is 83.69 (11)°. These two rings make dihedral angles of 30.53 (15) and 84.53 (16)° with the central N—N=C—C=N—N dihydrazonoethane plane. Intermolecular C—H...π interactions are observed.

In the title compound, C11H15FN2O5, the five-membered ring has an envelope conformation, while the six-membered ring is essentially planar, with a maximum deviation of 0.032 (2) Å from the mean plane. The crystal packing is stabilized by intermolecular N—H...O and O—H...O hydrogen bonds, generating a layer structure parallel to (001).

In the title compound, C10H8N3S+·NO3−·H2O, one of the N atoms of the benzimidazole unit is protonated, unlike than that in the thiazole group. This protonation leads to equalization of the bond angles at the two N atoms of the benzimidazole group. The benzimidazole and thiazole systems are almost coplanar, forming a dihedral angle of 0.5 (2)°. In the crystal, the nitrate anion and water molecule bridge the thiabendazolium cations through N—H...O and O—H...O hydrogen bonds, leading to a supramolecular network based on an infinite one-dimensional chain using [001] as base vector.