Search

The adverse health effects of trans fatty acids (TFA) are well recognised. The Commission Regulation (EU) 2019/649 specifies that foods should not contain more than 2 g of industrially produced TFA (i-TFA) per 100 g of fat. This study aimed to investigate the fatty acid profile, with focus on TFA and i-TFA, of foods widely consumed in Greece that are purported to contain high TFA concentrations. Sweet and savoury (i.e. non-sweet), prepacked and non-prepacked (i.e. loose) processed foods (N = 140) were sampled. After lipid extraction, the fatty acid profile of each sample was determined by gas chromatography. Estimation of ruminant TFA (r-TFA) was based on butyric acid values. i-TFA was assessed after subtraction of r-TFA from total TFA. Both total and i-TFA contents of cakes, biscuits, croissants and doughnuts on average were low (

The 3D lanthanum-dicarboxylate MOF [La2(hex)3(H2O)4]3H2O, (1), (hex = trans,trans-muconic acid) has been obtained at 50 °C, in a silica gel column, either via in situ transformation of the 2D MOF [La2(hex)3(H2O)6]9H2O, (2), published previously, or directly. The structure is made up of metal–ligand layers pillared by a ligand dianion. The comparison of the crystal structures of the two MOFs allowed us to propose a possible mechanism of the 2D to 3D transformation. The presence of many short olefinic contacts allowed the formation of three photoproducts at different yields, the major one being the rtct isomer for the 3D MOF and the rttc one for the 2D MOF. In both cases, the three photoreactions proceed with the parallel reaction scheme. The comparison of the crystal structures of 1 and 2 allowed the photoreactivity differences observed to be explained.

A synthesis of functionalized 4,5-bis(phenylimino)-1,3-thiazolidine-2-ylidenes via a simple reaction between ketene [Formula: see text]-acetals (derived from isothiocyanates and acetonitrile derivatives) with N,[Formula: see text]-diphenyloxalimidoyl dichloride in the presence of KOH in DMF is described. When CS[Formula: see text] was used as the heterocumulene component, the reaction led to the formation of 4,5-bis(phenylimino)-1,3-dithiolan-2-ylidene derivatives, in moderate to good yields.

A series of Lanthanide MOFs of hydromuconic acid (H2hymuc) with cations of different size (La3+, Ce3+, Gd3+, Y3+) were generated at room temperature, pH = 5.5–5.8, using water as solvent. Two microporous genuine supramolecular isomers were found for the larger cations (La3+, Ce3+) sustained either by discrete (H2O)18 clusters or by infinite water tapes, consisting of fused tetramers, pentamers and hexamers. The smaller cations (Gd3+, Y3+) produced a 2D phase, considered as catenane isomer of previously published lanthanide MOFs with adipic acid. MOFs obtained with Ce3+, Gd3+and Y3+ undergo irreversible solvent-mediated transformation, yielding isomorphous 3D two-fold interpenetrated MOFs. The close structural similarity between the 2D phase and the 3D interpenetrated one indicated a possible mechanism for this transformation.

A series of thiazolidine derivatives have been synthesized via tandem reaction of primary amines, isothiocyanates, and bis(imidoyl) chlorides in DMF at room temperature.

The sodium salt of methyl xanthate derives from the reaction of carbon disulfide and sodium hydroxide (1:1) in methanol. Addition of an acetonitrile solution of silver nitrate and tri-aryl-phosphine in 1:2 molar ratio, form the complexes with general formula [Ag(CH3OCS2)(Ar3P)2] (Ar3P = triphenylphosphine (tpp, 1), tri(p-tolyl)phosphine (tptp, 2) and tri(m-tolyl)phosphine (tmtp, 3)). The complexes have been characterized by melting point, FT-IR, UV–Vis, 1H, 31P NMR spectroscopic data and X-ray crystallography. The stability of the Ag–P bond in solution was determined by 31P NMR resonances signals. The photosensitivity of 1–3 against UVB radiation is studied by means of UV–Vis spectroscopy. The stronger photosensitivity is exhibited by 1. The LogP was calculated in order to correlate the influence of lipophilicity on biological activity. The steric demands of arylphosphine were assessed through determination of the cone angles, volumes and H-all atom contacts. Complex of tri(m-tolyl)phosphine exert the greatest steric repulsion (higher cone angle). Hirshfeld surface volumes (2 occupied the greatest space) were analyzed to clarify the nature of the intermolecular interactions. Complexes 1–3 were tested for their in vitro cytotoxic activity against human adenocarcinoma cancer cell lines: MCF-7 (breast, estrogen receptor (ER) positive), MDA-MB-231 (breast, estrogen receptor (ER) negative) and MRC-5 (normal human fetal lung fibroblast cells) with sulforhodamine B (SRB) colorimetric assay. Molecule 3 with the lower H-all atoms inter-molecular interactions exhibits the higher activity against MCF-7 cells. The results are correlated with those obtained from heteroleptic silver complexes of tri-aryl-phosphines and carboxylates analogs to 1–3 where the xanthate is replaced by carboxylates. The structure activity relationships (SAR) study underlines the significance of the ligand type on the bioactivity of these compounds.

The reaction of dialkyl acetylenedicarboxylates with 1-aryl-2-nitroethanones in the presence of pyridine leads to dialkyl 5-aryloyl-isoxazole-3,4-dicarboxylates through a novel mechanism, which involves a [2+2] cycloaddition/ring opening/cyclization sequence.

A simple one-pot synthesis of highly functionalized 1,2,4-diselenazolidines is described. Treatment of an acyl chloride with potassium selenocyanate in acetone gave an acyl isoselenocyanate and propane-2-selone, which both reacted with benzylamine or its derivatives to give the required products.

A one-pot synthesis of functionalized trichloromethylated pyrimidines from the reaction of trichloroacetimidamides, generated by the addition of guanidine derivatives to trichloroacetonitrile, and acetylenic esters, in good yields is described.

A novel iodine-mediated reaction of 2,6-dimethylquinoline with Knoevenagel condensation products of malononitrile with benzaldehydes, leading to a facile, one-pot synthesis of 2-aryl-3-(6-methylquinolin-2-yl)cyclopropane-1,1-dicarbonitriles, in moderate to good yields, is described.

A 2D lanthanum-dicarboxylate MOF of the formula [La2(hex)3(H2O)6]·9H2O (H2hex = trans,trans-hexadiendioic acid or trans,trans-muconic acid) has been synthesized by the silica gel technique. The structure consists of metal–organic layers separated by a 2D network of water molecules. The metal–organic layers are made up of La3+ arrays linked by the muconate ligands. Within a layer there is an infinite chain of short contacts between olefinic bonds allowing formation, upon UV irradiation, of three photoproducts. One of them was completely unexpected and its formation is explained by complex molecular movements in the solid state. The thermal instability of the MOF allowed isolation of five photochemically active lower hydrates. The rate constants of all hydrates were determined and show significant variations between them, attributable to structural rearrangements within the metal–organic layer brought about upon dehydration.

Treatment of a dimethylsulfoxide solution of 2-thioorotic acid (THO) with copper(I) halides unexpectedly results in the formation of the [Cu(L)(DMSO)2] complex, where L is the tetradentate N2O2-donor bis(4-carboxylato-6-oxo-pyrimidine-2-yl)sulfide dianion formed in situ by metal-assisted desulfurization of 2-thioorotic acid. The complex features a tetragonally distorted octahedral copper(II) center with two pyrimidine N atoms and two carboxylate O atoms of the ligand, forming a square plane, whereas two O atoms of DMSO solvate molecules occupy the axial positions. The molecular structure, electronic properties and the energetics of the metal–ligand interactions have been studied on the level of density functional calculations. The new compound was evaluated for its in vitro antibacterial activity, DNA degradation activity and for its efficacy as anticancer agent against different cancer and normal human and murine cell lines as well.

The reaction of copper(I) halides with 2-thiouracil (TUC), 6-methyl-2-thiouacil (MTUC), and 4-methyl-2-mercaptopyrimidine (MPMTH) in the presence of triphenylphosphine (tpp) in a 1:1:2 molar ratio results in a mixed-ligand copper(I) complex with the formulas [Cu2(tpp)4(TUC)Cl] (1), [Cu2(tpp)4(MTUC)Cl] (2), [Cu(tpp)2(MPMTH)Cl]·(1)/2CH3OH (3), [Cu(tpp)2(MTUC)Br] (4), and [Cu(tpp)2(MTUC)I]·(1)/2CH3CN (5). The complexes have been characterized by FT-IR, (1)H NMR, and UV-vis spectroscopic techniques and single-crystal X-ray crystallography. Complexes 1 and 2 are binuclear copper(I) complexes. Two phosphorus atoms from tpp ligands are coordinated to the copper(I) ions, forming two units that are linked to each other by a deprotonated TUC or MTUC chelating ligand through a sulfur bridge. A linear Cu-S-Cu moiety is formed. The tetrahedral geometry around the metal centers is completed by the nitrogen-donor atom from the TUC or MTUC ligand for the one unit, while for the other one, it is completed by the chloride anion. Two phosphorus atoms from two tpp ligands, one sulfur atom from MPMTH or MTUC ligand, and one halide anion (Cl, Br, and I) form a tetrahedron around the copper ion in 3-5 and two polymorphic forms of 4 (4a and 4b). In all of the complexes, either mono- or binuclear intramolecular O-H···X hydrogen bonds enhance the stability of the structures. On the other hand, in almost all cases of mononuclear complexes (with the exception of a symmetry-independent molecule in 4a), intermolecular NH···O hydrogen-bonding interactions lead to dimerization. Complexes 1-5 were studied for their catalytic activity for the intermolecular cycloaddition of iodonium ylides toward dihydrofuran formation by HPLC, (1)H NMR, and LC-HRMS spectroscopic techniques. The results show that the geometry and halogen and ligand types have a strong effect on the catalytic properties of the complexes. The highest yield of dihydrofurans was obtained when "linear" complexes 1 and 2 were used as the catalysts. The activity of the metal complexes on the copper(I)-catalyzed and uncatalyzed intramolecular cycloaddition of iodonium ylide is rationalized through electronic structure calculation methods, and the results are compared with the experimental ones.

Olive mill wastewater (OMW) generated during the oil extraction from Olea europea L. var. koroneiki olives was sampled at the beginning, the middle and the end of the harvesting season for three successive crop production years, and from four olive mills. OMW samples were examined in respect to their physicochemical characteristics, fatty acid composition of the lipid fraction, and adverse effects on biomass production of nine white-rot fungi of the basidiomycetous genus Pleurotus . Total N, nitrogen species, potassium and phosphate concentrations as well as total phenolics content of OMW samples were influenced by the crop year but not from the harvest period (albeit higher values for nitrate, nitrite, phosphate and potassium as well as total phenolics contents were obtained during ripening of olives), whereas protein concentration, total organic carbon and total solids were not significantly affected by the crop year or the harvest period. In addition, fatty acids composition, i.e. nC14:0, nC16:1Δ9cis, nC17:1Δ10cis, nC18:0, nC18:1Δ9cis, nC22:0 and nC24:0 varied significantly during different crop years and harvest periods. Olive fruits maturity and biannual alternate-bearing appear to play key-roles in the fatty acid variation detected in OMW samples. OMW toxicity as evaluated by the mycelium growth of Pleurotus strains was influenced significantly by the phenolic content of OMW samples obtained during three successive crop years; in contrast, the olives harvest period did not affect Pleurotus biomass production. Hence, experimental data indicated that selected Pleurotus strains could serve as bioindicators of OMW toxicity. Development of viable OMW detoxification processes as well as the exploitation of the effluent’s fertilizing value are discussed in the light of the above findings.

Ten mixed-ligand Co(II) compounds with 2-hydroxy-benzophenones(ketones) and neocuproine(neoc) were synthesized and characterized by physicochemical and spectral (IR, UV–Vis) data. The cyclic voltammetry study in CH3CN gave all the expected waves for the redox processes of the metal Co(II) and the studied ligands. The X-ray diffraction study of two representative compounds proved the two different geometries, octahedral for [Co(2-hydroxy-benzophenone)2(neoc)] (3) and trigonal bipyramidal for [Co(2-hydroxy-4-methoxybenzophenone)(neoc)Br] (10). Additionally, the precursor compound [Co(neoc)Br2]·CH3OH·H2O (11) was proved by (X-ray) to posses tetrahedral geometry. The molecular structure and the possible isomers of the trigonal bipyramidal complex 10 were studied by means of density functional calculations (DFT). The thermal stability was investigated by means of simultaneous TG/DTG–DTA technique in nitrogen atmosphere up to 1000 °C, where metallic cobalt was found as the solid residue.

Imidoyl chlorides (generated from isocyanides and acyl chlorides) reacts with triisopropyl phosphite, in a Perkow-type reaction, to produce 1-alkoxycarbonyl-2-(alkylimino)vinyl diisopropyl phosphate, which undergo a smooth reaction with bidentate nucleophilic intermediates obtained from the reaction between malononitrile and heterocumulenes, such as arylisothiocyanates or carbon disulfide to produce polarized olefins containing 2-dicyanomethylene-2,3-dihydrothiazole and 2-dicyanomethylene-1,3-dithiole moieties.

A one-pot synthesis of functionalized trichloromethylated pyrimidines from the reaction of trichloroacetimidamides, generated by the addition of guanidine derivatives to trichloroacetonitrile, and acetylenic esters, in good yields is described.

A synthesis of cis-3-aryl-3a,8b-dihydro-3a,8b-dihydroxy-1-phenylindeno[1,2-c]pyrazol-4(1H)-ones in good yields from the sequential reaction between benzaldehydes, phenylhydrazine, and indan-1,2,3-trione in MeCN is described (Scheme"…1). Helvetica Chimica Acta

A diastereoselective synthesis of 2-aryl-1-(cyclohexylimino)-1,2-dihydropyrrolo[1,2-a]quinoline-3,3(3aH)-dicarbonitriles is developed through a one-pot four-component reaction of malononitrile, benzaldehydes, quinoline and cyclohexyl isocyanide in a simple, mild, and efficient protocol. Journal of the Iranian Chemical Society

A series of co-crystals of trans-1,2-bis(4-pyridyl) ethylene (bpe) with aliphatic saturated or unsaturated dicarboxylic acids, of the type [(bpe)(L)] (L = dicarboxylic acid), were prepared and characterized by single crystal X-ray crystallography. In all cases chains of the type acid···bpe···acid were formed via strong O–H···N hydrogen bonds. The chains were further linked between them by weak C–H···O hydrogen bonds, π–π and herringbone interactions to form three-dimensional structures. Thermal analysis showed considerable elevation of the melting/decomposition point of the co-crystals with respect either to both components or to bpe, ascribed to the formation of multiple complementary C–H···O bonds as well as to π–π interactions between the two conformer molecules. When L = fumaric acid, the two components stack separately with their C═C bonds strictly parallel between them at 3.83 A from one another. However, photodimerization reaction takes place only between the olefin bonds of bpe. Photodimerization ...

The trichloroacetamidine intermediates, generated by addition of benzylamine derivatives to trichloroacetonitrile, react with the Knoevenagel condensation product of ninhydrin and malononitrile to afford trichloromethylated [3.3.3]propellanes, in good yields. When benzylamine was used, a plane-symmetrical spiro-compound was obtained.

The solid compounds [La(3)(chel)(Hchel)(3)(H(2)O)(8)]center dot H(2)O (1) and [La(Hchel)(H(2)O)(6)](2)[La(2)(Hchel)(4)(H(2)O)(4)]center dot 10H(2)O (2) (H(3)chel = 4-hydroxypyridine-2,6-dicarboxylic acid or chelidamic acid) were isolated from aqueous solutions upon mixing La(3+) cations and chelidamic acid at various pHs (pH 5-10). Compound I is a two-dimensional (213) coordination polymer consisting of La(Hchel)and La(Hchel)(2) units connected bycoordination bonds. Compound 2 is an ion-pair complex made Lip of alternating layers of La(Hchel)(+) and La(2)(Hchel)(4)(2-) ionic units linked between them by lattice water Molecules. The comparison of the two structures showed that the 2D coordination polymer, 1, is formed by a dehydration-condensation reaction between the La(Hchel)(+) and La(2)(Hchel)(4)(2-) units. The relative positions of these units in the crystal lattice suggest that the assembly of 1 takes place by a dehydration-condensation reaction between oligomeric layers of opposite charge and not by reaction between individual ions of opposite charge. Crystal Growth & Design

The reaction of dialkyl acetylenedicarboxylates with 1-aryl-2-nitroethanones in the presence of pyridine leads to dialkyl 5-aryloyl-isoxazole-3,4-dicarboxylates through a novel mechanism, which involves a [2+2] cycloaddition/ring opening/cyclization sequence.

A novel supramolecular structure, [C8H11N2S]2‚(C6Cl2O4), based on hydrogen bonding of the organic S-benzylthiuronium (SBT) cation and the chloranilate dianion, is presented. Chloranilic acid or 2,5dichloro-3,6-dihydroxy-1,4-benzoquinone, is a strong quinoidal diphenic acid (p K1 ) 1.09 and pK2 ) 2.42), with molecular formula C6Cl2O4H2 (H2CA). The CA-dianions and the aromatic rings of the SBTcations form columns along the c-axis giving an ordered pattern of dianions surrounded by densely populated areas of SBT-cations. Each CA-dianion forms eight hydrogen bonds with the amine protons of six SBT-cations, through its oxygen atoms. In this way, an extended H-bond network, containing infinite chains of alternative R 4 2 (8) and R2 2 (9) cyclic patterns, is obtained. The whole arrangement leads to a C2/c space group crystal structure, with unit cell dimensions a ) 15.109 A,b ) 11.606 A, andc ) 14.390 A and with unit cell angles of R) A ) 90°, and ‚ ) 97.01°, and average density of 1.43 g/cm 3 . Dissolution of the crystalline material in DMSO leads to the formation of associated organic ions or charge-transfer complexes as evidenced from the bathochromic shift of the absorption band of chloranilic acid from 420 to 520 nm.

[Cd(phen)2(CA)]n (I, where phen is 1,10-phenanthroline and CA2− is the dianion of 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone) has been synthesized and its crystal structure has been determined by single-crystal X-ray diffraction at room temperature. The crystal of I is built from infinite chains of chloranilate-bridged cadmium(II) leading to a zig-zag structure, with the phenanthroline ligands being stacked between the chains. These interactions assist the formation of a closely packed 3D structure. The coordination environment of cadmium(II) – very scarce in its chemistry – is square antiprismatic. The polymer was also characterized with spectroscopic (IR, Raman, DRS) and thermogravimetric (TG, DTA) techniques.

Silver(I) bromide reacts with 2-mercapto-3,4,5,6-tetrahydropyrimidine (StpmH2, C4H8N2S) in DMSO with an excess of triethylamine to give a water-insoluble complex of formula [Ag6(μ2-Br)6(μ2-StpmH2)4(μ3-StpmH2)2]n (1), while the reaction of silver(I) nitrate with StpmH2 under the same conditions gives a water-insoluble complex of formula [{Ag4(μ2-StpmH2)6}(NO3)4]n (2). The products were characterized by elemental analyses, and FT-IR far-IR, UV/Vis, 1H and 13C NMR spectroscopy. Crystal structures of complexes 1 and 2 were determined by X-ray diffraction. Complex 1, C24H48Ag6N12S6, crystallizes in the triclinic system space group P , a = 8.041(1) A, b = 12.838(4) A, c = 13.281(2) A, α = 68.40(1)°, β = 72.97(1)°, γ = 87.80(2), Z = 2, forming a one-dimensional infinite ribbon structure by strong interatomic interactions of two μ2-Br bonds with Ag(1). Complex 2, C24H48Ag4N16O12S6, crystallizes in the orthorhombic system, space group Cmc21, and a = 32.148(3) A, b = 9.461(2) A, c = 7.234(1) A, α = β = γ = 90°, Z = 8, forming infinite Ag−S−Ag chains which are bridged to each other by a sulfur atom of μ2-StpmH2 ligands. Complexes 1 and 2 were studied for their cytostatic activity against murine leukemia (L1210) and human T-lymphocyte (Molt4/C8 and CEM) cells and for their antiviral activity against a wide variety of viruses. They are markedly cytostatic at 50% inhibitory concentration (IC50) values ranging from 3 to 17 μg/mL. None of the compounds showed appreciable antiviral activity at subtoxic concentrations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Reaction of 4-formylantipyrine with thiosemicarbazide, N(3)-methylthiosemicarbazide and N(3)-ethylthiosemicarbazide produced the expected thiosemicarbazones, 1, 2 and 3. The three thiosemicarbazones were then reacted with K2PdCl4 to produce [Pd(NS)2] complexes, 4, 5, and 6, respectively, with coordination by the imine nitrogen and thiolate sulfur of the anionic thiosemicarbazone moiety. The thiosemicarbazones and their palladium complexes have been characterized by spectral IR, UV–Vis and 1H, 13C NMR and electrochemical techniques. The crystal structure of 6 has been obtained and found to be highly symmetrical with a trans arrangement of the two bidentate ligands.

Erbium. fumarate [Er-2(fum)(3)(H2O)(4)].8H(2)O, 1, (fum = fumarate dianion) crystallizes at room temperature in a silica gel column. The structure is three-dimensional and consists of layers of erbium fumarate pillared by fumarate dianions acting in the bis-chelating mode. The layers contain arrays of erbium cations bridged by fumarate dianions acting in the bis-bidentate bridging mode. The relatively large channels formed in the direction of the a and c axes are filled by water molecules that form a hydrogen bonded layer, comprising cyclic hexamers with both boat and chair conformations and cyclic decamers with boat-chair-boat conformation. The water molecules are reversibly removed at 90 degreesC. The evacuated metal-organic framework, 2, is stable up to 400 degreesC. Both compounds 1 and 2 exhibit weak antiferromagnetic interactions. Crystal Growth & Design

Silver(I) chloride reacts with 2-mercapto-nicotinic acid (H(2)mna, C6H5NO2S) in the presence of an excess of triethylamine in DMSO to form a hexanuclear, water soluble, cluster of formula {[Ag-6(mu(3)-Hmna)(4)(mu(3)-mna)(2)](2-) (.)[(Et3NH)(+)](2)(.)(DMSO)(2)(.)(H2O)} (1). The complex 1 was characterized by elemental analyses, and FT-IR, UV-Vis and H-1 NMR spectroscopy. Crystal structures of complex 1 and the ligand, 2-mecapto-nicotinic acid (2), have been determined by X-ray diffraction. Compound 1, C52H68Ag6-N8O15S8, is monoclinic with a space group P2(1)/c (No. 14) and a = 11.7080(10), b = 16.2920(10), c = 18.3010(10) Angstrom, beta = 91.350(10)degrees, Z = 4. The entire molecule is ionic and consists of a double anionic hexa-nuclear cluster and two protonated triethylamine counter cations while it is solvated by two DMSO and one water molecule. The 2-mercapto-nicotinic acid (2), C6H5NO2S, is orthorhombic (space group Pna2(1) (No. 33), a = 8.3910(10), b = 13.2720(10), c = 5.892 Angstrom, Z = 4). An extended inter-molecular hydrogen bonding via (OH)-H-...-N contacts (O(1)H-...(5)[N(5)] = 1.8998, O(1)N-...(5) = 2.8049 Angstrom) links the molecules forming a supramolecular two-dimensional network. Complex 1, was evaluated for anti-HIV-RT activity. It was found to inhibit the human immunodeficiency viral replication reverse transcriptase (HIV-RT) with calculated inhibiting concentration (IC50) 0.01275 +/- 0.00115 mg ml(-1). (C) 2002 Elsevier Science B.V. All rights reserved. Inorganica Chimica Acta

Acylketene, generated in situ from 1,3-dioxinone (I) reacts with phenylhydrazine and aromatic aldehydes to give pyrazolidinones.

The oxidation of 2-hydroxynaphthaldehyde oxime with lead(IV) acetate (LTA) gave a mixture of naphtho[1,8-de][1,2]oxazine and a spiro dimer. LTA oxidation of 6-bromo (or nitro)-2-hydroxynaphthaldehyde oximes provided only spiro dimers. Similar treatment of (2-hydroxy-1-naphthyl)keto oximes with LTA gave naphtho[1,8-de][1,2]oxazines and benzo[cd]indol-3(1H)-ones. Low temperature oxidation of 1-(2-hydroxy-1-naphthyl)propan-1-one oxime furnished 2-ethylbenzo[cd]indol-3(1H)-one and 1-ethylnaphtho[1,2-d]isoxazole-2-oxide. peri- and o-Naphthoquinone nitrosomethides are invoked as intermediates that undergo peri- and o-cyclisation and intermolecular cyclodimerisation. (C) 2001 Elsevier Science Ltd. All rights reserved. Tetrahedron

Single crystals of [Cd(terephthalate)(H2O)3].4H2O (1), triaquo(1,4-benzenecarboxylato-κO)cadmium tetrahydrate, are grown in a silica gel column. Crystal structure analysis shows that (1) is a polymer with metal-organic chains stacked along the a axis forming layers parallel to the ab plane. These layers are linked by an unusual hydrogen-bonded network formed by the water molecules (both `free' and coordinated ones) and the carboxylate O atoms. This network comprises tridymite-like O8 cages which `propagate' in the direction of the a axis, mimicking the way they `propagate' along the c axis in hexagonal ice.

The structure and dehydration behavior of the porous 3D coordination polymer {[La2(adipate)3(H2O)4]6H2O}n are described. Each La3+ is coordinated by nine oxygen atoms belonging to five carboxylate ...

Imidoyl chlorides (generated from isocyanides and acyl chlorides) reacts with triisopropyl phosphite, in a Perkow-type reaction, to produce 1-alkoxycarbonyl-2-(alkylimino)vinyl diisopropyl phosphate, which undergo a smooth reaction with bidentate nucleophilic intermediates obtained from the reaction between malononitrile and heterocumulenes, such as arylisothiocyanates or carbon disulfide to produce polarized olefins containing 2-dicyanomethylene-2,3-dihydrothiazole and 2-dicyanomethylene-1,3-dithiole moieties.

A practical microwave-assisted, one-pot method for the construction of 4-acetyl-2-phenyl-5-aryl-3-pyrazolidinones via a tandem reaction between phenylhydrazine, aromatic aldehydes, and but-1-ene-1,3-dione (acylketene), in moderate to good yields, is reported. When methylhydrazine and 4-methylphenylhydrazine hydrochloride were used instead of phenylhydrazine, the reaction led to the formation of 3-oxobutanohydrazide derivatives. Synlett

Three 2D and 3D photoreactive MOFs of trans,trans-muconic acid with Er(3+) and their corresponding isomorphous Y(3+) phases were synthesized and their photoreactivity was studied as a function of the crystal environment.

The process involves the in situ formation of zwitterionic intermediates from pyridines or quinolines and dimethyl acetylene dicarboxylate.

The reaction of β-dicarbonyl phenyliodonium ylides with diphenylketene at room temperature affords mixtures of lactone and aurone derivatives. The initial electrophilic attack of the iodonium ylide on the C(β) position of the diphenylketene, followed by cyclization of the zwitterionic species, and subsequent ejection of iodobenzene, affords the lactone and aurone cycloadducts. Treatment of β-dicarbonyl iodonium ylides with acyl chlorides yields α-chloroenones with good to excellent yields.

The reactive zwitterionic intermediates, generated from addition of pyridine derivatives to dialkyl acetylenedicarboxylates, react with 1-methylimidazole/dichloroketene adduct to afford functionalized dialkyl 1-(2,2-dichloroacetyl)indolizine-2,3-dicarboxylates in moderate yields. Synlett

The assembly of Er(3+) and Y(3+) cations with trans,trans-muconic acid affords a photoreactive 3D microporous MOF that, upon UV irradiation, undergoes a cycloaddition reaction (SCSC up to 55%), with in situ formation of a strained ladderane. Chemical Communications

The conformation of title compounds has been determined in the solid state by X-ray crystallography and in solution by nmr spectroscopy. MM2 and molecular dynamics calculations were used to determine the conformation of one of these compounds in vacuo and in solution

The molecular bilayer motif reported here is formed by trimesic acid and Cd2+. The ligand acts as a three-connected node while the metal is a simple spacer. The assembly of these motifs into a three-dimensional structure forms cavities into which coordinated and lattice water molecules are located.

2-(Alkenyloxy)naphthalene-l-carbaldehyde oximes are oxidized with potassium iodide, iodine and sodium bicarbonate directly to novel naphthopyranoisoxazoles. Naphthopyranoisoxazoles are also prepared from 2-(3-chloroallyloxy)napbthalene-1-carbaldehyde oxime or 2-(alkynyloxy)naphthalene-1-carbaldehyde oximes by oxidation with sodium hypochlorite and triethylamine. The oxidation of 2-(alkenyloxy)naphthatene-1-carbaldehyde oximes with sodium hypochlorite and triethylamine afforded novel naphthopyranoisoxazolines. The former reaction is tentatively proposed to occur via activation of the alkene side chain by means of an iodonium intermediate and either 1,3-dipolar interaction with a nitrile oxide side-group or cyclization with a hydroximic acid iodide side-group. Synthesis-Stuttgart

Organotin(IV) complexes with the formulas [(C(6)H(5))(3)Sn(mbzt)] (1), [(C(6)H(5))(3)Sn(cmbzt)] (3), and [(C(6)H(5))(2)Sn(cmbzt)(2)] (4) (Hmbzt = 2-mercaptobenzothiazole and Hcmbzt = 5-chloro-2-mercaptobenzothiazole) have been synthesized and characterized by elemental analysis; FT-IR, Raman, (1)H, (13)C, and (119)Sn NMR, and Mossbauer spectroscopic techniques; and X-ray crystallography at various temperatures. The crystal structures of complexes 1, 3, and 4 were determined by X-ray diffraction at room temperature [295(1) or 293(2) K]. The complexes [(C(6)H(5))(3)Sn(mbzo)] (2) and [(n-C(4)H(9))(2)Sn(cmbzt)(2)] (5) (Hmbzo = 2-mercaptobenzoxazole) were synthesized by new improved methods, and their structures were determined at low temperature [100(1) K] and compared to those solved at room temperature. Comparison with {(CH(3))(2)Sn(cmbzt)(2)]} (6), already reported, was also attempted. The influence of temperature on the geometry of the complexes is discussed. In the cases of complexes 1-3, three carbon atoms from phenyl groups and one sulfur atom and one nitrogen atom from thione ligands form a tetrahedrally distorted trigonal-bipyramidal geometry around the five-coordinate tin(IV) ion. In complexes 4-6, two carbon atoms from aryl groups and two sulfur atoms and two nitrogen atoms from thione ligands form a distorted tetrahedral geometry, tending toward octahedral, around the six-coordinate tin(IV) ions, with trans-C(2), cis-N(2), and cis-S(2) configurations. Although the C-Sn and S-Sn bond distances are found to be constant in compounds 1-6, their N-Sn bond lengths vary significantly (from 2.635 to 3.078 angstrom), with the longer distances found in the cases of five-coordinate complexes 1-3. Inorg Chem

The self-assembly of four symmetrically substituted tri-aryl-benzene derivatives of formula C24H15X3, where X = H (1), Cl (2), COOMe (3), and COOH (4), was studied as a function of the substituent X. Crystal packing analysis of compounds 1-3 showed that in 1, there are no strong face-to-face stacking interactions, whereas in both compounds 2 and 3, molecular columns were formed, held by numerous "lateral" C-H center dot center dot center dot Cl and C-H center dot center dot center dot O hydrogen bonds, respectively. However, strong intermolecular face-to-face aromatic interactions, appropriate for excimer formation, were observed only in 3, in line with results obtained by fluorescence spectroscopy. The pi-pi aromatic interactions are significantly stronger in the case of the triacid 4, but a lack of adequate single crystals of this compound prevented any detailed study for correlating crystal architecture with fluorescence emission observed. However, FT-IR and TEM experiments showed the existence of dimeric H-bonds and short (0.35 nm) distances between the phenyl rings. Crystal Growth & Design

The photochemistry of three structurally very similar triphenylmethylsilanes 1, 2, 3 [p-X-C(6)H(4)-CPh(2)-SiMe(3): X = PhCO, 1; H, ; Ph(OCH(2)CH(2)O)C, 3] is described by means of 248 and 308 nm nanosecond laser flash photolysis (ns-LFP), femtosecond LFP, EPR spectroscopy, emission spectroscopy (fluorescence, phosphorescence), ns-pulse radiolysis (ns-PR), photoproduct analysis studies in MeCN, and X-ray crystallographic analysis of the two key-compounds 1 and 2. The photochemical behavior of 1, 2 and 3 is discussed and compared with that of a fourth one, 4, bearing on the p-position an amino group (X = Me(2)N) and whose detailed photochemistry we reported earlier (J. Org. Chem., 2000, 65, 4274-4280). Silane 1 undergoes on irradiation with 248 and 308 nm laser light a fast photodissociation of the C-Si bond giving the p-(benzoyl)triphenylmethyl radical (1*) with a rate constant of k(diss)= 3 x 10(7) s(-1). The formation of 1* is a one-quantum process and takes place via the carbonyl triplet excited state with high quantum yield (Phi(rad)= 0.9); the intervention of the triplet state is clearly demonstrated through the phosphorescence spectrum and quenching experiments with ferrocene (k(q)= 9.3 x 10(9) M(-1) s(-1)), Et(3)N (1.1 x 10(9) M(-1) s(-1)), and styrene (3.1 x 10(9) M(-1) s(-1)) giving quenching rate constants very similar to those of benzophenone. For comparative reasons radical 1* was generated independently from p-(benzoyl)triphenylmethyl bromide via pulse radiolysis in THF and its absorption coefficient at lambda(max)= 340 nm was determined ([epsilon]= 27770 M(-1) cm(-1)). We found thus that the p-PhCO-derivative 1 behaves similar to the p-Me(2)N one (the latter giving the p-(dimethylamino)triphenylmethyl radical with Phi(rad)= 0.9), irrespective of their completely different ground state electronic properties. In contrast, compounds 2, 3 that bear only the aromatic chromophore give by laser or lamp irradiation both, (i) radical products [Ph(3)C* and p-Ph(OCH(2)CH(2)O)C-C(6)H(4)-C(*)Ph(2), respectively] after dissociation of the central C-Si bond (Phi(rad)= 0.16), and (ii) persistent photo-Fries rearrangement products (of the type of 5-methylidene-6-trimethylsilyl-1,3-cyclohexadiene) absorbing at 300-450 nm and arising from a 1,3-shift of the SiMe(3) group from the benzylic to the ortho-position of the aromatic ring (Phi approximately 0.85 for 2). Using fs-LFP on 2 we showed that the S(1) state recorded at 100 fs after the pulse decays on a time scale of 500 fs giving Ph(3)C* through C-Si bond dissociation. In a second step and within the next 10 ps trityl radicals either escape from the solvent cage (the quantum yield of Ph(3)C* formation Phi(rad)= 0.16 was measured with ns-LFP), or undergo in-cage recombination to photo-Fries products. Thus, singlet excited states (S(1)) of the aromatic organosilanes (2, 3) prefer photo-Fries rearrangement products, while triplet excited states (1, 4) favor free radicals. Both reactions proceed via a common primary photodissociation step (C-Si bond homolysis) and differentiate obviously in the multiplicity of the resulting geminate radical pairs; singlet radical pairs give preferably photo-Fries products following an in-cage recombination, while triplet radical pairs escape the solvent cage (MeCN). The results demonstrate the crucial role which is played by the chromophore which prescribes in a sense, (i) the multiplicity of the intervening excited state and consequently that of the resulting geminate radical pair, and (ii) the dominant reaction path to be followed: the benzophenone- and anilino-chromophore present in silanes 1 and 4, respectively, impose effective intersystem crossing transitions (k(isc)= 10(11) s(-1) and 6 x 10(8) s(-1), respectively) leading to triplet states and finally to free radical products, while the phenyl chromophore in 2 and 3, possessing ineffective isc (k(isc)= 6 x 10(6) s(-1)) leads to photo-Fries product formation via the energetic high lying S(1) state [approximately 443 kJ mol(-1)(106 kcal mol(-1))].

Thermal rearrangement of (+/-)-spiro {naphthalene-1(2H)4'-(naphtho-[2', 1': 2,3]pyrano[4,5-c]furazan)]-2-one-11'-oxides in DMF or acetic anhydride at 140 degrees C gave an isomeric mixture of (+/-)-spiro {naphthalene-1 (2H), 1'-(5'-hydroxyphenalene[1,2-c]furazan)}-2-one-2'-oxides and 4'-oxides. The rearranged structure was confirmed from X-ray analysis and was consistent with the through space NOE data. The rearrangement is suggested to be an overall tandem isomerization process. Using variable temperature H-1 NMR spectroscopy the lower limit for the isomerisation barrier for a pair of tautomers was calculated to be 22 kcal mol(-1) at 423 K. The isomerisation equilibrium for a pair of isomers was studied by variable temperature 1H NMR. The lower limit for the isomerisation barrier was calculated to be 22 kcal mol(-1) at 423 K. This low value may be indicative of the difficulty encountered in separating the isomers by chromatography. Semiempirical AMI and molecular mechanics calculations suggest that the (+/-)-spiro {naphthalene-1(2H), 1'-(5'-hydroxyphenalene[1,2-c]-furazan) 1-2-one-2'-oxides are more stable than their 4'-oxide counterparts, in accordance to the X-ray structure. The lower population of the 4'-oxide isomers relative to that of the 2'-oxide isomers was explained in terms of an unfavourable intramolecular steric interaction found in the low energy structure of the former. (c) 2005 Elsevier Ltd. All rights reserved. Tetrahedron

The synthesis and characterization of copper(II) complexes with a potent non-steroidal anti-inflammatory drug, tolfenamic acid, Htolf, with formula [Cu(tolf)(2)L](2) (where L is H2O or DMF, N,N-dimethylformamide) were investigated. The crystal-and molecular structure Of [Cu(tolf)(2)(DMF)](2) was reported. Crystallographic data are as follows: monoclinic system, space group P2(1)/n with cell constants a = 9.068(2) Angstrom, b = 14.514(3) Angstrom, c = 22.826(4) Angstrom, V = 2948.9(10) Angstrom(3) and Z = 2. The crystal structure consists of binuclear, quadruply bridged neutral molecule with a Cu-Cu bond length of 2.6075(19) Angstrom. The complex is self-assembled via C-H-pi intermolecular stacking interactions. Spectroscopic and electrochemical studies were reported. The superoxide dismutase activity is measured and compared with those of superoxide dismutase enzyme, SOD, the free ligand and related copper complexes with nonsteroidal anti-inflammatory drugs, NSAIDs. IC50 value was measured by the Fridovich test (1.97 +/- 0.17 muM), which showed that [Cu(tolf)(2)L](2) is a good superoxide scavenger. (C) 2003 Elsevier Inc. All rights reserved. J Inorg Biochem

Reaction of H2PtCl4 and K2PdCl4 with 2-hydroxyacetophenone N(4)-ethylthiosenticarbazone, H(2)Ap4Et, afforded [Pt(Ap4Et)(H(2)Ap4Et)] and [Pd(Ap4Et)(H(2)Ap4Et)]. Their crystal and molecular structures are reported and represent the first 1:2 thiosemicarbazone complexes with ligands having both different formal charge and denticity. The dianion, Ap4Et(2-), coordinates in a planar conformation to palladium(II) or platinum(II) via the phenolato 0, imine N and thiolato S atoms, while the neutral molecule exhibits monodentate coordination by the thione S atom. Intra-, intermolecular hydrogen bonds and C-H... pi contacts lead to aggregation and a supramolecular assembly. Electronic, IR, and NMR spectral data, as well as electrochemical measurements, are included. The pK(a) values of the poorly water soluble H2Ap4Et were obtained spectrophotometrically in aqueous solutions of constant ionic strength. (C) 2004 Elsevier B.V. All rights reserved. Inorganica Chimica Acta

Five new organotin(IV) molecules with the heterocyclic thioamides; 2-inereaptobenzothiazole (Hmbzt), 5-chloro-2-mercaptobenzothiazole (Hcmbzt), 3-methyl-2-mercaptobenzothiazole (mmbzt) and 2-mercaptonicotinic acid (H(2)mna) of formulae [(n-C4H9)(2)Sn(mbzt)(2)] (1), [(C6H5)(2)Sn(mbzt)(2)] (2), {(CH3)(2)Sn(cmbzt)(2)].1.7(H2O)} (3), [(n-C4H9)(2)SnCl2(mmbzt)(2).(CH2Cl2)] (4) and {[(C6H5)(3)Sn](2)(nma).[(CH3)(2)CO]} (5) have been synthesized and characterized by elemental analysis, H-1-, C-13-NMR, FT-IR and Mossbauer spectroscopic techniques. Crystal structures of molecules 1, 3 and 5 have been determined by X-ray diffraction at 173(l) K (I and 5) and 293(2) K (3). Compound 1 C22H26N2S4Sn, is monoclinic, space group C2/c, a =44.018(2), b = 8.8864(5), c = 12.8633(7) Angstrom, beta = 104.195(5)degrees, Z = 8. Compound 3 is also monoclinic, space group P2(1)/c and a = 17.128(2) Angstrom, b = 17.919(2) Angstrom, c = 7.3580(10) Angstrom, beta = 98.290(10)degrees, Z=4. In both molecules 1 and 3, two carbon atoms from aryl groups, two sulfur and two nitrogen atoms from thione ligands form a distorted octahedral geometry around tin(IV) with trans-C-2, cis-N-2, cis-S-2 configurations. Compound 5 C45H39NO3SSn2 is monoclinic, space group P2(1)/n, a=9.1148(2) Angstrom, b=29.2819(6), c=15.5556(4) Angstrom, beta=106.285](9)degrees, Z=4. Complex 5 contains two I(C6H5)3Sn(IV)] moieties linked by a double deprotonated 2-mercaptonicotinic acid (H(2)mna). Both tin(IV) ions are five coordinated. This complex is the an example of a pentacoordinated Ph3SnXY system with an axial-equatorial arrangement of the phenyl groups at Sn(1) atom. Compounds 1, 3 and 5 were tested for in vitro cytotoxicity against the cancer cell line of sarcoma cells (mesenchymal tissue) from the Wistar rat, polycyclic aromatic hydrocarbons (benzo[a]pyrene) carcinogenesis. Compound 5 exhibits strong cytotoxic activity, while complexes 1 and 3 show less cytotoxic activity. (C) 2003 Elsevier Inc. All rights reserved. J Inorg Biochem