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Twelve selenourea having fluorinated fragments were synthesized and fully characterized and their fluorine content influence studied by 77Se NMR.

The tropical tree Calophyllum brasiliense Cambess. (Clusiaceae) grows in rain forests from Brazil to Mexico. Its leaves, as well as those of other Calophyllum species, are rich sources of chromanone acids, such as apetalic acid, isoapetalic acid, and their derivatives. Apetalic acid has shown significant antimycobacterial activity. The biological activity of apetalic acid has been related to the configuration of three asymmetric centers and the stereochemistry of the molecule; however, the C-19 configuration in the acidic side chain has not been fully resolved. For this reason, the unequivocal determination of the absolute configuration by means of X-ray crystallography in a sample of unique homogeneous apetalic acid stereoisomer was the most important point to start this study. Chiral amides were prepared using the carboxyl group. We determined the C-19 stereochemistry of apetalic acid and its specific chiral derivatives using NMR, X-ray diffraction, and molecular mechanics. Finally, we observed that steric hindrance in the side chain of apetalic acid leads to restriction of rotation around the pivotal linkage C-10–C-19, establishing chiral centers at C2(R), C3(S), and C19(R). We were able to separate the derivatives of these two high-rotatory-barrier conformers of apetalic acid by forming diastereoisomeric amides with phenylglycine methyl ester having a chiral center at C-2′. Our results confirmed the existence of atropisomerism in the apetalic acid molecule.

The solvatomorphs of [Pd(1,10-phen)(2,3,5,6-S-C6F4H)2] 1 (1,10-phen = 1,10-phenanthroline), i.e., 1·S (S = C6H62, C6H6Cl 3 and C6H6Br 4) and [Pd(1,10-phen)(2,3,4,5,6-S-C6F5)2]·C6H6Br 5 were studied to shed further light on the solvatomorphism phenomena.

A series of Rh(i) complexes with fluorinated NHC ligands were prepared and used as efficient catalysts in the arylation of aldehydes.

Through experimental and computational studies we were able to prove that the hydrogen atom of the imine group forms structurally relevant C–H···F hydrogen bonds and that the fluorine atoms in the ...

Reactions of group 10 transition metals with the ditopic ligand dipicolyldithiocarbamate (DPDTC) were performed. Thus, 1:2 reactions of [Ni(CH3COO)2], [Pd(COD)Cl2] or [Pt(COD)Cl2] with DPDTC produced monomeric complexes of the type [M(κ2-SCS-DPDTC)2, M = Ni (1), Pd (2) or Pt (3)] with the dithiocarbamate ligand (DTC) coordinated in a typical chelate κ2-SCS fashion. Interestingly, the reaction of [NiCl2] with DPDTC, under similar conditions, afforded the organic compound 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyri-dine-3(2 H)-thione (4) as unique product. In order to prove the ditopic nature of the ligand DPDTC, complex [Pd(κ2-SCS-DPDTC)2] (2) was further reacted with [ZnCl2] in a 1:2 M ratio to yield the trinuclear complex [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5). The molecular structures of all compounds were determinate by typical analytical techniques including the unequivocal determination of all structures by single crystal X-ray diffraction analysis. As expected, complexes 1–3 are isostructural, and the metal centres exhibiting slightly distorted square-planar geometries. While in 5, the trinuclear nature of the complex in confirmed exhibiting a nice combination of tetrahedral-square planar-tetrahedral geometries for the Zn-Pd-Zn centres respectively. Keywords: Dithiocarbamate, Metal-sulphur complexes, Trinuclear complexes, Ditopic ligands, Hetero-aromatic compound, Di-(2-picolyl)amine cyclization

Zinc(II) and cadmium(II) complexes of general formula [M(iPr2P(X)NC(Y)NC5H10-κ2-X,Y)2] (M = Zn, X = Y = S (4), X = S, Y = O (5), X = O, Y = S (6), and M= Cd, X = Y = S (7), X = S, Y = O (8), X = O, Y = S (9)) have been synthesized and characterized by using elemental analysis, IR and NMR spectroscopy, and thermogravimetric analysis (TGA). SCXRD molecular structures of complexes 6, 7, and 9 revealed ligand binding to the metal center in a bidentate fashion in an overall distorted tetrahedral coordination geometry. TGA showed that 4–9 decompose in a single step to their corresponding metal sulfides. Aerosol assisted chemical vapor deposition (AACVD) at 450 °C and subsequent annealing at 600 °C were used to examine 4–9 as single source precursors (SSPs) for the deposition of nanostructured metal sulfide thin films (4F–6F unannealed ZnS films and 7F–9F unannealed CdS films). GIXRD confirmed that the resultant films have a nanocrystalline hexagonal structure with the (002) preferential orientation, except for 9F, and the grain size varied from 15 to 24 nm. Scanning electron microscopy and atomic force microscopy (SEM and AFM) images revealed a relatively dense grain columnar structure. The elemental composition and mapping studies showed that the near-stoichiometric MS thin films are homogeneously distributed. The as-deposited ZnS thin films (4F–6F) displayed phosphorus content between 6.4 and 8.2%, while CdS films showed no phosphorus content except for 9F, which showed P 2%. The optical properties of the films such as direct optical energy gap (Eg), and Raman and photoluminescence (PL) spectra displayed some differences related to the employed SSP, being more significant for films obtained from precursors containing the hybrid ligand –P(O)NC(S)– (3), which showed a major phosphorus content (6F and 9F). A sharp excitonic emission at room temperature, as well as multiple Raman overtones, shows the high optical quality of the investigated CdS thin films. The PL spectra of ZnS films showed emissions attributed to the near band edge and different crystalline imperfections such as vacancies and interstitials.

The title compound crystallizes with two independent mol­ecules in the asymmetric unit. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, C—H⋯π, I⋯S and I⋯I inter­actions into a three-dimensional network., Two crystallographically independent mol­ecules (A and B) are present in the asymmetric unit of the title compound, C11H9IN2OS, which differ mainly in the dihedral angle between the phenyl and thia­zole rings [38.94 (16) and 32.12 (15)°, respectively]. In the crystal, the mol­ecules form ⋯A⋯B⋯A⋯B⋯ chains along the [001] and [010] directions through moderate N—H⋯O hydrogen bonds and C—H⋯π inter­actions, respectively. The overall three-dimensional network is formed by I⋯I and I⋯S inter­actions. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯C/C⋯H (26.2%), H⋯H (20.9%), H⋯I/I⋯H (19.4%) and H⋯O/O⋯H (6.8%) inter­actions.

The synthesis of four novel non-symmetric Ni(II)-POCOP pincer complexes meta-functionalized with either benzothiazole or benzimidazole at the central aryl ring is described. All complexes were fully characterised in solution by various analytical techniques and the molecular structures in the solid state of complexes 1b, 2a and 2b were unequivocally determined by single crystal X-ray diffraction analysis. In addition, the Ni(II)-POCOP pincer complexes were efficiently used as catalysts in the synthesis of diarylketones by cross-coupling reactions of functionalized benzaldehydes and boronic acid derivatives under relatively mild conditions. An important aspect of this transformation is the dependence on the steric properties of the donor groups (OPR2) of the pincer ligands, the more active compounds having the phosphinitos bearing isopropyl groups (1a and 2a) than those containing tert-butyl substituents (1b and 2b).

The title compound, C30H44O3[systematic name: 6aR,6 bR,8aS,9aR,12aR,14bR)-4,4,6a,6;b,8a,14b-hexamethyl-12-methyleneicosahydro-3H-phenanthro[1′,2′:6,7]indeno[2,1-b]furan-3,11(2H)-dione], is a triterpene lactone, which was isolated from dichloromethane extract ofElaeodendron trichotomum(Turcz.) Lundell (celastraceae) stem bark. The compound has a lupane skeleton and consists of four fused six-membered rings and two five-membered rings. In the crystal, molecules are linked by weak C—H...O hydrogen bonds into a three-dimensional network. The configuration of ochraceolide A was proposed based on analogue compounds which belong to the lupane type.

Porphyrins meso -substituted with p -phenylene vinylene (OPV) were synthesized. The porphyrin dendrimers obtained showed a strong dependence on the type of connection of the dendritic branches. In the instance of the all trans -conformation linkages, an H-type aggregate is obtained for the linear OPV and strong J-aggregate for the ramified OPV. An adequate intramolecular energy transference stemming from the OPVs (donors) to the respective cores was observed. Furthermore, the number oligo( p -phenylene vinylene) (OPV) groups linked to the porphyrin system increase the energy transfer efficiency. This behavior also was observed in the photovoltaic studies.

We report for the first time the high sorption properties of a molecular rotor with no permanent voids or channels in its crystal structure. Such crystalline phase originates from THF, DCM, or the irreversible desolvation of entrapped benzene molecules. From these, the benzene in its solvate form acts as rotation stopper, as supported by dynamic characterization using solid-state 2H NMR experiments. In the solvent-free form, the diffusion of small quantities of iodine vapors caused a significant change in the intramolecular rotation, increasing the known activation energy to rotation from 8.5 to 10.6 kcal mol–1. Notably, those results paved the way for the discovery of the high CO2 uptake (201.6 cm3 g–1 at 196 K, under 1 atm) and acetone (5 wt %), a sorption property that was attributed to both, the restriction of the molecular rotation at low temperatures and the flexibility of the molecular axle made of conjugated p-(ethynylphenylene), surrounded by carbazole.

In this paper, we present the use of the interaction between aromatic rings—usually called π–π interaction—as the main tool in the organization of coordination complexes in a crystal. To do so, we selected coordination compounds with aromatic rings pointing outside the molecules to favor their self-assembly through these interactions. Here, we report the molecular and crystal structures of three Cu(II) complexes: [Cu2(terpy)2(bz)2](ClO4)2 (1), [Cu2(terpy)2(tfipth)2] (2) and [Cu4(terpy)4(tfipth)2(ClO4)2](ClO4)2 (3), where terpy = 2,2′:6′,2′′ terpyridine, bz = benzoate and tfipth = tetrafluoro-isophthalate. In the three crystals, the interaction between aromatic rings organizes molecules in chains that closely pack with disordered anions or water molecules located in the space between the chains. A study of the Crystal Structure Database (CSD) indicates that the main interaction in terpy molecules is between a lateral ring and the central ring of different molecules and when terpy molecules point in opposite directions, they tend to form chains, suggesting that these interactions can be used as a design tool. The metal complexes were designed to obtain a square pyramidal structure around the metal ion, but we observed a contact between the non-coordinated O (carboxylate) and the Cu(II) ion. We studied the presence of this interaction and its nature with computational chemistry.

Bioactivity-directed fractionation of the combined culture medium and mycelium extract of the endophytic fungus Xylaria feejeensis strain SM3e-1b, isolated from Sapium macrocarpum, led to the isolation of three known natural products: (4S,5S,6S)-4-hydroxy-3-methoxy-5-methyl-5,6-epoxycyclohex-2-enone or coriloxine, 1; 2-hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 2; and 2,6-dihydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione or fumiquinone B, 3. This is the first report of compound 3 being isolated from this species. Additionally, four new derivatives of coriloxine were prepared: (4R,5S,6R)-6-chloro-4,5-dihydroxy-3-methoxy-5-methylcyclohex-2-enone, 4; 6-hydroxy-5-methyl-3-(methylamino)cyclohexa-2,5- diene-1,4-dione, 5; (4R,5R,6R)-4,5-dihydroxy-3-methoxy-5-methyl-6-(phenylamino)cyclohex-2-enone, 6; and 2-((4-butylphenyl)amino)-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 7. X-ray analysis allowed us to unambiguously determine the structures and absolute configuration of semisynthetic derivatives 4, 5, and 6. The phytotoxic activity of the three isolated natural products and the coriloxine derivatives is reported. Germination of the seed, root growth, and oxygen uptake of the seedlings of Trifolium pratense, Medicago sativa, Panicum miliaceum, and Amaranthus hypochondriacus were significantly inhibited by all of the tested compounds. In general, they were more effective inhibiting root elongation than suppressing the germination and seedling oxygen uptake processes as shown by their IC50 values.

Herein we report the synthesis of the highly stable crystalline carbazole-based rotor 3 with simultaneous rapid solid state internal rotation and good fluorescence emission. Single crystal and powder X-ray diffraction studies along with microscopy revealed a phase transition from a labile benzene solvate (phase I) to highly stable crystals (phase II) that feature fast intramolecular rotation in the megahertz regime at room temperature, according to variable temperature 2H solid state NMR experiments using isotopically enriched analogues. In addition to the megahertz rotation within its crystals, this crystal phase II displays enhanced solid state fluorescence with a higher quantum yield of ϕ = 0.28, relative to the emission of this compound in THF solution (ϕ = 0.06). These two solid state properties are significantly different from shorter compounds 1 and 2 (static and nonemissive) included here for comparison purposes.

In the title salt, each cation shows a moderate distortion between the planes of the amide groups and the quinolinium rings. The tri­fluoro­methane­sulfonate anions are linked to organic cations via N—H⋯O hydrogen-bonding inter­actions involving the NH amide groups. In the crystal, weak C—H⋯O hydrogen bonds and π-stacking inter­actions between the quinolinium and phenyl rings link the organic cations into chains., In the title compound, C23H18N3O3 +·CF3SO3 −, the asymmetric unit contains two crystallographically independent organic cations with similar conformations. Each cation shows a moderate distortion between the planes of the amide groups and the quinolinium rings with dihedral angles of 14.90 (2) and 31.66 (2)°. The quinolinium and phenyl rings are slightly twisted with respect to each other at dihedral angles of 6.99 (4) and 8.54 (4)°. The tri­fluoro­methane­sulfonate anions are linked to the organic cations via N—H⋯O hydrogen-bonding inter­actions involving the NH amide groups. In the crystal, the organic cations are linked by weak C—H⋯O(nitro group) inter­actions into supramol­ecular chains propagating along the b-axis direction.

Liquid-like dynamics of a covalent 1,4-phenylene rotator have been unveiled in 1 with a brominated stator showing type-II halogen bonds. This singular rotation is favored by synergistic molecular changes in stacked molecules, according to VT solid state NMR, 1H T1 relaxometry and VT X-ray experiments of this highly crystalline compound.

The stoichiometric control of the reaction of phloroglucinol with different chlorophosphines ClPR2, R = iPr (1), tBu (2) or Ph (3), leads to the direct and high yield synthesis of the p-hydroxy functionalized POCOP ligands [C6H3-5-OH-1,3-(OPR2)2]. Typical reactions of these compounds with NiCl2·6H2O provide a facile access to the corresponding POCOP pincer derivatives [NiCl{C6H2-4-OH-2,6-(OPR2)2}], R = iPr (4), tBu (5) or Ph (6).

Bioactivity-directed fractionation of the organic mycelium extract of the endophytic fungus Acremonium camptosporum W. Gams (Clavicipitaceae), isolated from the leaves of Bursera simaruba (Burseraceae), led to the isolation of six major heterodimeric polyketides, including one not previously characterized acremoxanthone derivative. In addition, the already known acremoxanthone C, acremonidins A and B, and acremoxanthones A and B were obtained. The structure of the new compound was established by extensive NMR studies, including DEPT, COSY, NOESY, HSQC, and HMBC methods. The trivial name proposed for this compound is acremoxanthone E. In addition, the structure of acremoxanthone C was unequivocally established for the first time, through X-ray crystal-structure analysis. The anti-oomycete activities of the pure compounds were tested against four economically important phytopathogenic oomycetes. Inhibitory concentration for 50% diameter growth reduction, IC50 , values for the four phytopathogens ranged from 6 to 38 μM. Also, in parallel, the cytotoxic activities against six cancer cell lines were evaluated showing IC50 values similar to those of cisplatin. To the best of our knowledge, this is the first report on three different groups of heterodimeric polyketides, linked by a bicyclo[3.2.2]nonene, such as xanthoquinodins, acremonidins, and acremoxanthones, which are isolated from an endophytic fungus. In addition, a common biosynthetic origin could be proposed.

Sapium macrocarpum (Euphorbiaceae) is a tropical tree located mainly in the southern part of Mexico and in Central America, and it is used in the Mayan traditional medicine for the treatment of several skin diseases. The dichloromethane-MeOH extract of the aerial parts displayed cytotoxic activity against certain cancer cell lines. Lupeol (1), lupenone (2), sitostenone (3), β-sitosterol (4), stigmasterol (5), sitosteryl β-D-glucopyranoside (6) and the rare diterpene tonantzitlolone A (7) were characterized from this extract. The structural analysis allowed the 1H NMR reassignments for H-12α and H-12β, and for H-13α and H-13β of tonantzitlolone A (7). The cytotoxic activity of compounds 1-3, 6 and 7 was evaluated against selected cancer cell lines. Compounds 3, 6 and 7 displayed clear activity against K562 (leukemia). This is the first report on the chemical constituents of S. macrocarpum, and points out that this species is an additional source of tonantzitlolone A. Compound 7 has only been reported previously from species of the Stillingia, Sebastiania and Sapium genera, which belong to the Hippomaninae subtribe of the family Euphorbiaceae.

From the stem bark of Mangifera indica, seven cycloartane-type secondary metabolites were isolated. Compound 1 has been isolated for the first time from M. indica, whereas compounds 2 (2a and 2b, as an epimeric mixture), 3, and 4 are new triterpenoid-type cycloartanes. Unambiguous (13) C and (1) H NMR assignments for these compounds and the known compounds mangiferonic acid (compound 5), isomangiferolic acid (compound 6), ambolic acid (compound 7), and friedelin (compound 8) are reported; the latter because full NMR data for these compounds are not available in the literature.

The reactions of mono-, bis- and tetrapicolyl-p-tert-butylcalix[4]arene derivatives functionalised in the phenolic positions (L 1 –L 4 ) with copper(II) acetate resulted in the formation of discrete complexes or extended coordination polymers. The centrosymmetric dimer [Cu2(μ-O2CCH3)4(L 1 )2] 1, obtained with monodentate L 1 , has square pyramidal coordination around the copper centres and a cone conformer of monopicolyl-calix[4]arene acting as an axial ligand, with a molecule of acetonitrile hosted within its cavity. The potentially bidentate L 2 acts as a monodentate ligand, affording the complex [Cu2(μ-O2CCH3)4(L 2 )2] 2, which based on spectroscopic and combustion analysis data has a similar coordination sphere around Cu(II). Compound L 3 bridges two dicopper units in the coordination polymer [Cu2(μ-O2CCH3)4(μ-L 3 )] n 3, with the calixarene hosting a molecule of tetrahydrofuran. Finally, compound L 4 reacts with 4 equivalents of copper(II) acetate, presumably generating a two-dimensional coordination...

Through an analysis of the Cambridge Structural Database, CSD, we found that Cu(II) complexes with planar tridentate amines and two monodentate ligands tend to present a square pyramidal geometry. We decided to test the 2,2′ : 6′2″-terpyridine, trpy, as a ternary ligand to build [Cu(trpy)(CA)(H2O)] tectons, CA representing an organic carboxylate, in the supramolecular synthesis of an H-bonded coordination compound. Six new crystal structures are reported and analyzed with other similar compounds reported in the CSD. In all of them a square pyramidal geometry and 1-D supramolecular structures are obtained through an O–H⋯O hydrogen bond between the coordinated water molecule and one O atom from the carboxylate ligand. Thus, molecular and supramolecular control over the Cu(II) complexes is achieved.

A solid state study of the chloride complexation ability of a series of salicylaldehyde thiosemicarbazone Ni(II) complexes is presented. Complexes of general formula [Ni(5-X-HSalTSC)PPh3]Cl, where 5-X-HSalTSC− represent the monoanion of 5-X-salicylaldhehyde thiosemicarbazones (with X = MeO, Br, NO2), were studied in comparison with the analog neutral complex [Ni(5-NO2-SalTSC)PPh3]. The crystal structure of the compounds show that the coordinated thiosemicarbazones chelate the choride anions through two N–H hydrogen bonds.

A series of platinum thiolate complexes of the type [Pt(bpy)(SRF)2] (bpy = 2,2′-bipyridyl and SRF = − SC6F5 (1), − SC6F4-4-H (2)) have been synthesized in good yields by metathetical reactions of [Pt(bpy)Cl2] with [Pb(SRF)2], (SRF = − SC6F5, − SC6F4-4-H) and their crystal structures determined. The effect of the different thiolates in the structural properties of the complexes both in the solid state and in solution have been analyzed. The analyses in solid state suggests that the difference in π–π interactions among the aromatic rings may cause the different arrangements of the molecules in the crystal structures.

The disubstituted calix[4]arene derivative 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-bis(2-pyridylmethoxy)calix[4]arene 2, which crystallises in the monoclinic space group P2 1 /n, was functionalised in the phenolic O–H groups with (tert-butoxycarbonyl)methoxy groups. The yield of the isolated cone and partial-cone conformers of tetrasubstituted 5,11,17,23-tetra-tert-butyl-25,27-bis[(tert-butoxycarbonyl)methoxy]-26,28-bis(2-pyridylmethoxy)calix[4]arene 3a and 3b, depends on the identity of the alkali metal hydride employed to deprotonate 2. Partial-cone conformer 3b crystallises in the monoclinic space group P2 1 /n, with an inverted (tert-butoxycarbonyl)methoxy-containing phenol moiety. The product distribution of 3a and 3b was interpreted based on the relative stabilities of the alkali metal complexes with the doubly deprotonated derivative of 2, and the monoanionic derivative [(tert-butoxycarbonyl)methoxy-2]− , by molecular mechanics analysis.

In the title compound, C23H16O2S, the thiophene group is rotationally disordered into two fractions almost parallel to each other, with occupation factors of 0.523 (7) and 0.477 (7), and subtending dihedral angles of 10.5 (5) and 9.3 (5)°, respectively, to the thiophene group. The molecules are held together by weak C—H...O and C—H...π hydrogen bonds, producing a laminar arrangement, which are further connected in a perpendicular fashion by S...π contacts [S...centroid = 3.539 (8) and 3.497 (8) Å]. In spite of the presence of the entended pyrene group, the structure does not present any parallel π–π stacking interactions. The structure was refined as an inversion twin.

The molecular and crystal structures of a series of fluoro-aniline complexes of general formula trans-[PdCl2(NH2ArF)2], with ArF = C6H3-2,3-F2 (1), C6H3-2,5-F2 (2), C6H3-3,4-F2 (3), C6H3-3,5-F2 (4), C6H2- 2,3,4-F3 (5), C6H2-2,4,5-F3 (6), C6H2-2,4,6-F3 (7), were determined. Analysis of these structures demonstrate that robust reliable supramolecular synthons are obtained through Pd−N−H···Cl−Ph hydrogen-bond interactions. The possible influence of the polarization of the different ArF aromatic rings in the arrangement of the molecules within the hydrogen-bonded structures is discussed.

The synthesis of bis-imino nickel(II) NNN pincer complexes of the type [NiCl 2 {C 5 H 3 N-2,6-(CHNAr f ) 2 }]; Ar f =C 6 H 3 -2,3-F 2 (1), C 6 H 3 -2,5-F 2 (2), C 6 H 3 -3,4-F 2 (3), C 6 H 3 -3,5-F 2 (4), C 6 H 2 -2,3,4-F 3 (5), C 6 H 2 -2,3,6-F 3 (6), C 6 H 2 -2,4,5-F 3 (7), C 6 H 2 -2,4,6-F 3 (8), has been achieved and their reactivity in alkyl- and arylthiolation reactions of halobenzenes examined. The use of fluorinated substituents Ar f on the imines has allowed the tuning of the electronics in these complexes and the influence of these substituents and those of the disulfides in the thiolation reactions have been analyzed.

Reaction of 4-formylantipyrine with N(4)-dimethylthiosemicarbazide and 3-piperidylthiosemicarbazide produces the N(4)-dimethylthiosemicarbazone (1), and the 3-piperidyl-thiosemicarbazone (2), respectively. Compound 1 is triclinic, space group P-1 with a = 6.329(1) A, b = 11.699(1) A, c = 11.943(1) A, α = 65.83(1)°, β = 80.83(1)°, γ = 84.90(1)°, and V = 796.1(1) A3 with Z = 2, for Dcalc = 1.324 g/cm3. Compound 2 is triclinic, space group P-1 with a = 6.784(1) A, b = 10.485(2) A, c = 13.462(3) A, α = 102.05(2)°, β = 98.61(2)°, γ = 101.32(2)°, and V = 899.8(5) A3 with Z = 2, for Dcalc = 1.319 g/cm3. Reaction of 4-aminoantipyrine with phenyl isothiocyanate produced N-antipyrine-N′-phenylthiourea (3). Compound 3 is monoclinic, space group P21/n with a = 6.863(7) A, b = 15.361(3) A, c = 16.332(5) A, β = 90.35(6)°, and V = 1720.7(18) A3 with Z = 4, for Dcalc = 1.306 g/cm3. Compounds 1 and 2 have intermolecular hydrogen bonding between the carbonyl oxygen of the antipyrine moiety and the NH hydrogen of the thiosemicarbazone moiety. In 3 the two unique molecules are held together as a dimer by interactions of the two thiourea NH's and the antipyrine moiety's\break oxygen.

Reactions of 2-aminopicolines with 2- and 4-tolyl isothiocyanates yielded N-2-(4-picolyl)-N′-4-tolylthiourea, 1, N-2-(3-picolyl)-N′-4-tolylthiourea, 2, and N-2-(4-picolyl)-N′-2-tolylthiourea, 3. Compound 1 is monoclinic, of space group P21/c with a = 7.456(1) A, b = 13.135(3) A, c = 13.959(3) A, β = 104.99(3)°, and V = 1320.5(5) A3 with Z = 4, for d calc = 1.294 g/cm3. Compound 2 is triclinic, of space group $$P\bar 1$$ with a = 6.877(3) A, b = 7.590(5) A, c = 13.213(9) A, α = 78.38(2)°, β = 77.96(4)°, γ = 86.36(4)°, and V = 660.5(7) A3 with Z = 2, for d calc = 1.294 g/cm3. Compound 3 is monoclinic, of space group P21/c with a = 12.604(2) A, b = 15.592(3) A, c = 6.875(2) A, β = 91.05(2)°, and V = 1350.9(2) A3 with Z = 4, for d calc = 1.265 g/cm3. The three thioureas are found in both solid state and solution in a conformation resulting from intramolecular $${\text{N}}{\kern 1pt} ---{\kern 1pt} {\text{H}} \cdot \cdot \cdot {\text{N}}$$ hydrogen bonding. Compounds 1 and 3 present an intermolecular hydrogen bond involving the thione sulfur and the NH hydrogen, which is not present in 2 owing to the steric hindrance of the methyl group in the phenyl ring. The geometry of the molecule is affected by the position of the methyl groups on the pyridine and aryl rings.

The synthesis of monomeric pentacoordinated diorganotin(IV) complexes derived from pyridoxal hydrochloride and 4- or 5-R-substituted ortho-aminophenols is described. The complexes were characterized using UV–visible, infrared, mass, 1H NMR, 13C NMR and 119Sn NMR spectral techniques. The molecular structure of three complexes was established using X-ray diffraction: 3b and 3d show a distorted trigonal bipyramidal geometry, in which the basal plane is defined by the butyl groups and the iminic nitrogen atom, whereas the oxygen atoms from the aromatic ring occupy axial positions; in contrast, complex 3e exhibits a square pyramidal geometry. The cytotoxic activity of all complexes against human cell lines U-251 (glioblastoma), K-562 (chronic myelogenous leukemia), HCT-15 (human colorectal cancer), MCF-7 (human breast cancer) and SKLU-1 (non-small-cell lung cancer) was evaluated, and the inhibitory percentage values indicated higher activity than the reference standard, cisplatin. Acute toxicity studies were performed in vivo for the prepared complexes to determine the lethal medium dose (LD50) after intraperitoneal administration to mice.

The asymmetric unit of the title compound, [PdCl2(C10H8N2)]·0.5C4H8O2, consists of one PdIIcomplex molecule and a half-molecule of 1,4-dioxane, the complete molecule being generated by inversion symmetry. The PdIIatom has an almost square-planar coordination formed by the 2,2′-bipyridine ligand and two chloride ligands. Two intramolecular C—H...Cl hydrogen bonds occur. In the crystal, the PdIIcomplex and 1,4-dioxane molecules are connected by C—H...O hydrogen bonds, forming a layer parallel to (10-1). Within the layer, weak π–π interactions [centroid–centroid distance = 3.817 (4) Å] are observed between the pyridine rings.

From the fermentation mycelium of the endophytic fungus Edenia gomezpompae were obtained several phytotoxic compounds including two new members of the naphthoquinone spiroketal family, namely, palmarumycin EG1 (1) and preussomerin EG4 (4). In addition, preussomerins EG1–EG3 (7–9) and palmarumycins CP19 (2), CP17 (3), and CP2 (6), as well as ergosta-4,6,8(14),22-tetraen-3-one (5), were obtained. Compounds 2, 3, and 5 are new to this species. The structures of palmarumycins CP19 (2) and CP17 (3) were unambiguously determined by X-ray analysis. The isolates and mycelium organic extracts from four morphological variants of E. gomezpompae caused significant inhibition of seed germination, root elongation, and seedling respiration of Amaranthus hypochondriacus, Solanum lycopersicum, and Echinochloa crus-galli. The treatments also affected respiration on intact mitochondria isolated from spinach.

In the cation of the title molecular salt, C6H16NO+·Cl−, the N—C—C—O torsion angle is 176.5 (2)°. In the crystal, the cations and chloride ions are linked by N—H...O and O—H...O hydrogen bonds, generating a two-dimensional network parallel to (100).

Only recently have noncovalent interactions (notably hydrogen bonds) been used in deliberate strategies for connecting coordination complexes into extended networks. The significance of such intermolecular forces is further demonstrated in this structural study of four different 1,8-bis(dimethylamino)naphthalenium, [HDMAN]+, halo-metalates. The cation is unable to engage in any strong hydrogen-bond interactions and the resulting structures do not display any repeating topologies or motifs. This is in stark contrast with previous work on halo-metalates with cations capable of forming directional hydrogen bonds, e.g., 4,4-bipyridinium(2+); those structures contain charge-assisted MX...HN+ interactions between anions and cations resulting in well-defined 1-D and 2-D motifs. The [HDMAN]+ structures presented here, however, are determined by close-packing principles; no repeating motifs are observed, which emphasizes that hydrogen bonding is an effective tool for directed assembly of substantial coordination c...

Six Schiff base copper(II) complexes have been prepared and characterized, elemental analyses, mass, IR and electronic spectra, μeff and X-ray crystal structures being obtained. The X-ray study shows that the geometry around the metal atom is square planar for one of the complexes only and distorted square planar for the others. Electrochemical studies on the complexes, though revealing a dependence of the Cu(II)/Cu(I) potentials on electronic effects, also show that these are independent of the structure observed in the solid state. Besides, EPR studies of these complexes in DMF solution at 193 K suggest that the geometry of these complexes in solution is different to that observed in the solid state by X-ray crystallography.

Two novel compounds, celastroidine A (1) and B (2), were isolated from the roots of Hippocratea celastroides K. Their structures were elucidated by spectroscopical and X-ray diffraction studies. Celastroidine A (1) (C50H74O5) was identified as a Diels-Alder adduct of a triterpene plus a diterpene and celastroidine B (2) as a beyerane, a type of dimer of two diterpene (C40H60O4). Both compounds could be formed in vivo by a Diels-Alder reaction. Celastroidine A showed some antifeeding activity against the stored grain insect Sitophyllus zeamays.Key words: Hippocratea celastroides, Hippocrataceae, roots, Diels-Alder adducts, diterpenoids, triterpenoids, x-ray diffraction, insect antifeedants, stored grain insects, Sitophyllus zeamays, insecticidal plants, Diels-Alderase.

Through the careful design of a tecton and the selection of an adequate synthon we were able to design and build a non-centrosymmetric crystal through π–π stacking interactions.

A 1:2:2 complex of diaza crown ether 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, anthraflavic acid (2,6-dihydroxyanthraquinone) and water has been synthesized. The crystal is triclinic, P1, with a = 7.705(2), b = 10.871(2), c = 11.540(2) A, α = 100.40(2), β = 91.38(2), γ = 98.01(2)°, Z = 1, and Dcalc = 1.375 mg m−3. The main feature of the crystal structure is the formation of a supramolecular sheet by hydrogen bonding of the anthraflavic monoanions, not only head-to-tail through the hydroxyl oxygens, but sideways through the quinone oxygens. This complex represents an intermediate case between total transfer of protons of a hydroxy-guest to crown N-atoms, and no transfer.

The rhodium(II)-catalysed reaction of the diazoketone derived from 5-(4-methoxybenzoyl)-2,3-dihydropyrrolizin-1-carboxylic acid (anirolac) did not give the expected intramolecular cyclisation product but afforded the 2,3-dihydropyrrolizin-1-one only an elimination product. X-ray studies confirmed the structure.

There are two independent mol­ecules in the asymmetric unit of the title compound, C21H18N6S. The mol­ecules are linked by C—H⋯S and C—H⋯N inter­molecular and π–π stacking inter­actions.

The title compound, [PtFe(C6F6S)2(C17H14P)2], was obtained from the metathesis reaction of [Pt(dppf)Cl2] and [Pb(SC6F5)2] in CH2Cl2 [dppf is 1,1′-bis­(diphenyl­phosphino)ferrocene]. Two independent mol­ecules are found in the asymmetric unit. The PtII centers have a distorted square-planar environment with the P atoms of the dppf ligand coordinating to the metal centers in a bidentate fashion. The coordination of each Pt atom is completed by two –SC6F5 ligands in an anti conformation. The crystal packing exhibits inter­esting C—H⋯π stacking.

The title compound, C17H12O, crystallized with three independent molecules (A,BandC) in the asymmetric unit. In the crystal, the three independent molecules are linked by π–π interactions [centroid–centroid distances = 3.551 (3)–3.977 (2) Å], which lead to the formation of trimers. Between the trimers there are a number of C—H...π interactions generating a laminar arrangement parallel to (010). The methoxymethyl group in moleculeAis disordered over two sets of sites, with an occupancy ratio of 0.56 (9):0.44 (9).

Charge transfer molecular solids [diaqua tetrabenzo (b,f,j,n,) {1,5,9,13) tetraazacyclohexadecine] Ni(II) and Cu(II) bisanthraflavates were synthesized and characterized by IR, Mass Spectrometry, TGA, and X-ray diffraction on single crystals. Unit cell dimensions (A) a = 12.291(1), c = 14.574(1) A and a = 12.434(1), c = 14.066(1) A for Cu(II) and Ni(II) derivatives, respectively, space group P42/n in both cases. The obtained compounds show expected chemical and structural similarities. Tetraazamacrocycles are surrounded individually by a zig-zag, ribbon-like motif extending in the crystal by head-to-tail hydrogen bonding of monosubstituted anthraflavates. Electric conductivities were measured by the four points method as pellets from the variation of electric current through the sample as a function of temperature, for fixed voltages in the ohmic regime. Preliminary results indicate low conductivity values at room temperature but semiconductivity behaviour in the temperature range −150 to 170°C.

The title compound is C29H34O4, tetragonal, P43, a = b = 10.310(1), c = 23.871(2)A. The A, B, C, and D rings adopt envelope, half-chair, chair, and distorted chair conformations, respectively. The phenyl ring is planar. The methyl substituents at the A/B, C/D, and at C(17) are axial; and the –OCOCH3 group at C(17) and phenyl ring at C(16) are equatorial. The molecules in the crystal are held together by van der Waals forces and several C–H···O hydrogen bond interactions.

In the structure of the title compound, [Sn(C12H10N3O2)Cl2(C6H5)]·CH2Cl2, the SnIV ion is in a distorted octahedral coordination geometry, with the phenyl and the N,N′,O-donor 2-acetylpyridine 2-furylhydrazonate ligands in equatorial positions and the Cl atoms in axial positions. The crystal structure shows π–π interactions between the pyridine and the coordinated phenyl rings. In the crystal structure, the molecules pack forming channels filled with disordered solvent molecules.

The crystal structure of 5-methyl-acetophenonethiosemicarbazone monohydrate,A, and salicylaldehyde-2-methylthiosemicarbazone monohydrate,B, were determined using single crystal X-ray diffraction.A crystallizes in the monoclinic space groupC2/c, with lattice parametersa=14.161(2),b=15.753(1) A,c=11.084(1) A, β=112.59(1)° andZ=4, yielding a calculated density ofD calc=1.352 mg/m3.B crystallizes in the triclinic space groupP1, witha=7.233(2) A,b=7.371(2) A,c=11.841(2) A, α=82.77(2)°, β=78.33(2)°, γ=63.06(2)° andD calc=1.371 mg/m3 forZ=2,. In bothA andB the immine nitrogen and the sulfur atom areanti with respect to N2-C8. WhileA presents the usual intramolecular six membered hydrogen bond ring,B has instead an intermolecular hydrogen bond between the hydroxy moiety of the salicyladehyde and a water molecule. AM1 calculations agree with the experimental conformations observed in both compounds.