A new MoVI Schiff base complex: methanol[N′-(3-meth­oxy-2-oxidobenzyl­idene)benzohydrazidato]dioxido­molybdenum(VI)

In the title benzil­idene Schiff base molybdenum(VI) complex, [Mo(C15H12N2O3)O2(CH3OH)], the MoVI ion is coordinated by two oxide O atoms and by two O atoms and one N atom of the tridentate N′-(3-meth­oxy-2-oxidobenzyl­idene)benzo­hydrazidate (L) Schiff base ligand. The methanol O atom completes the distorted octa­hedral configuration of the MoVI atom. Strong O—H⋯N hydrogen bonds form a C(5) chain around a 21 screw axis. Weak C—H—O hydrogen bonds are also present

Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

The Grignard reaction of 2,3-O-isopropylidene-alpha-D-lyxo-pentodialdo-1,4-furanoside and benzylmagnesium chloride (or bromide) afforded a non-separable mixture of diastereomeric benzyl carbinols and diastereomeric o-tolyl carbinols. The latter resulted from an unexpected benzyl to o-tolyl rearrangement. The proportion of benzyl versus o-tolyl derivatives depended on the reaction conditions. Benzylmagnesium chloride afforded predominantly o-tolyl carbinols while the application of benzylmagnesium bromide led preferably to the o-tolyl carbinols only when used in excess or at higher temperatures. The structures of the benzyl and o-tolyl derivatives were confirmed unambiguously by NMR spectral data and X-ray crystallographic analysis of their 5-ketone analogues obtained by oxidation of the corresponding mixture of diastereomeric carbinols. A possible mechanism for the Grignard reaction leading to the benzyl -> o-tolyl rearrangement is also proposed

2D Bipyrimidine silver(I) nitrate: Synthesis, X-ray structure, solution chemistry and anti-microbial activit

Synthesis and X-ray single crystal structure analysis of the compound {[Ag₂(μ₂-bpym)(μ-O-NO₃)₂]}_n, (1), (where bpym = 2,2′-bipyrimidine) are presented. Compound (1) has a (6,3)-2D honeycomb structure with a tetrahedral coordination geometry around the Ag(I) ion. In contrary to the solid state structural investigation, ESI-MS for (1) in solution shows a strong peak at m/z 423.0269 which indicates that the [Ag(bpym)₂]⁺ cation is dominating instead of [Ag₂(bpym)]²⁺. The anti-microbial activity of (1) was screened against 15 multi-drug resistant bacteria in comparison to silver(I) sulphadiazine and it showed a high activity against Burkholderia mallei which causes glanders; with a MIC value of 4 μg/ml

catena-Poly[[bis­(N,N′-dimethyl­formamide)cadmium(II)]-μ2-oxalato]

The title compound, [Cd(C2O4)(C3H7NO)2]n, is isostructural with its MnII analogue. The structure comprises zigzag polymeric chains with the oxalate groups situated on inversion centres and the CdII atoms located on twofold rotation axes. The coordination geometry around CdII is distorted octa­hedral and the intra­chain Cd⋯Cd distance is 5.842 (1) Å. C—H⋯O hydrogen bonds exist between the parallel polymeric chains

Effects of Different Substituents on the Crystal Structures and Antimicrobial Activities of Six Ag(I) Quinoline Compounds

The syntheses and single crystal X-ray structures of [Ag(5-nitroquinoline)(2)]NO3 (1), [Ag(8-nitroquinoline)(2)]NO3 center dot H2O (2), [Ag(6-methoxy-8-nitroquinoline)(NO3)](n) (3), [Ag(3-quinolinecarbonitrile)(NO3)](n) (4), [Ag(3-quinolinecarbonitrile)(2)]NO3 (5), and [Ag(6-quinolinecarboxylic acid)(2)]NO3 (6) are described. As an alternative to solution chemistry, solid-state grinding could be used to prepare compounds 1 and 3, but the preparation of 4 and 5 in this way failed. The Ag(I) ions in the monomeric compounds 1, 2, 5, and 6 are coordinated to two ligands via the nitrogen atoms of the quinoline rings, thereby forming a distorted linear coordination geometry with Ag-N bond distances of 2.142(2)-2.336(2) angstrom and N-Ag-N bond angles of 163.62(13)degrees-172.25(13)degrees. The 1D coordination polymers 3 and 4 contain Ag(I) centers coordinating one ligand and two bridging nitrate groups, thereby forming a distorted trigonal planar coordination geometry with Ag-N bond distances of 2.2700(14) and 2.224(5) angstrom, Ag-O bond distances of 2.261(4)-2.536(5) angstrom, and N-Ag-O bond angles of 115.23(5)degrees-155.56(5)degrees. Hirshfeld surface analyses of compounds 1-6 are presented as d(norm) and curvedness maps. The d(norm) maps show different interaction sites around the Ag(I) ions, i.e., Ag center dot center dot center dot Ag interactions and possible O-H center dot center dot center dot O, C-H center dot center dot center dot O, C-H center dot center dot center dot N, and C-H center dot center dot center dot C hydrogen bonds. Curvedness maps are a good way of visualizing pi-pi tacking interactions between molecules. The antimicrobial activities of compounds 1, 2, and 6 were screened against 15 different multidrug-resistant strains of bacteria isolated from diabetic foot ulcers and compared to the antimicrobial activities of the clinically used silver sulfadiazine (SS). Compound 2 showed activity similar to SS against this set of test organisms, being active against all strains and having slightly better average silver efficiency than SS (5 vs 6 mu g Ag/mL). Against the standard nonresistant bacterial strains of Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, and Streptococcus pyogenes, compound 1 performed better than silver nitrate, with an average MIC of 6 mu g Ag/mL versus 18 mu g Ag/mL for the reference AgNO3. Electrospray ionization mass spectrometry (ESI-MS) analyses of compounds 3 and 6 in DMSO/MeOH confirm the two-coordinated Ag+ complexes in solution, and the results of the H-1 NMR titrations of DMSO solutions of 5-nitroquinoline and 8-nitroquinoline with AgNO3 in DMSO suggest that 5-nitroquinoline is more strongly coordinated to the silver ion

Induction of Laccase, Lignin Peroxidase and Manganese Peroxidase Activities in White-Rot Fungi Using Copper Complexes

Ligninolytic enzymes, such as laccase, lignin peroxidase and manganese peroxidase, are biotechnologically-important enzymes. The ability of five white-rot fungal strains Daedaleopsis confragosa, Fomes fomentarius, Trametes gibbosa, Trametes suaveolens and Trametes versicolor to produce these enzymes has been studied. Three different copper(II) complexes have been prepared ((Him)[Cu(im)4(H2O)2](btc) 3H2O, where im = imidazole, H3btc = 1,3,5-benzenetricarboxylic acid, [Cu3(pmdien)3(btc)](ClO4)3 6H2O) and [Cu3(mdpta)3(btc)](ClO4)3 4H2O, where pmdien = N,N,N0,N0 0, N0 0-pentamethyl-diethylenetriamine and mdpta = N,N-bis-(3-aminopropyl)methyl-amine), and their potential application for laccase and peroxidases induction have been tested. The enzyme-inducing activities of the complexes were compared with that of copper sulfate, and it has been found that all of the complexes are suitable for the induction of laccase and peroxidase activities in white-rot fungi; however, the newly-synthesized complex M1 showed the greatest potential for the induction. With respect to the different copper inducers, this parameter seems to be important for enzyme activity, which depends also on the fungal strains

Bis 4,5-diazafluoren-9-one silver(I) nitrate: synthesis, X-ray structures, solution chemistry, hydrogel loading, DNA coupling and anti-bacterial screening

Synthesis of bis-4,5-diazafluoren-9-one silver(I) nitrate I (dafone = 4,5-diazafluoren-9-one) and the low temperature X-ray single crystal structure of [Ag(4,5-diazafluoren-9-one)₂NO₃], crystal form 1, and a re-determination of [Ag(4,5-diazafluoren-9-one)₂]NO₃ . H₂O, crystal form 2 are presented. Crystal form 1 has a distorted trigonal planar coordination geometry around Ag(I) with an N-Ag-N bond angle of 123.45(7)^o. Crystal form 2 has a perfect linear coordination around Ag, with N-Ag-N 180.0^o. Compound I was characterized by ¹H-NMR, biological activity and ESI-MS in DMSO at room temperature. The biological activity was determined against 6 different resistant clinical isolates; two Gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and four Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, and Salmonella sp.) in comparison with 15 known antibiotics used in the treatment of diabetic foot infections. Compound I showed broad spectrum activity against all the test organisms. P. mirabilis and S. aureus and K. pneumoniae were the most sensitive clinical isolates (MIC = 4, 6 and 4 μg ml^-1, respectively). Three different hydrogels containing I or Ag₂SO₄ were prepared and the antimicrobial activity against Ps. aeruginosa (ATCC 15442) compared, showing more or less equal activity on a weight basis, but I seems to have a significant better performance per silver ion. The Ag(I) complex also binds more effectively to calf thymus DNA than the dafone ligand itself

Preparation and Crystal Structure of (1S, 5S, 7S, 8R)-8-Hydroxy-7-phenyl-2,6-dioxabicyclo[3.3.0]octan-3-one

The absolute configuration at two newly formed stereogenic centres (5S, 7S) during the key steps of the total synthesis of naturally occuring goniothalesdiol was established by single-crystal X-ray diffraction analysis relative to stereocentres (1S, 8R) of the title compound (alternatively named 3,6-anhydro-2-deoxy-6-phenyl-L-ido-1,4-hexonolactone, C12H12O4). The conformation of both 5-membered lactone and furanose fused rings is also discussed

5,5'-Bis(hydroxymethyl)-3,3'-dimethoxybiphenyl-2,2'-diol with a new three-dimensional 3-modal topology of synthons

The title lignin model compound, C₁₆H₁₈O₆, resides on a twofold axis parallel with the b axis, with the mid-point of the internal C-C(-x + 1, y, -z + 1/2) bond located on the twofold axis. The exo angles between the methoxy groups and the benzene rings deviate significantly from the expected value of 120° [125.15 (7) and 114.27 (6)°]. A 12-coordinated 3-modal three-dimensional net with a new topology was identified on the synthon level. A comparison of the flexibility of related o,o'-disubstituted biphenyl derivatives and biphenyl is presented, with the angles between the ring planes in substituted biphenyls found to be in the range 40-70°

Ca-10((CrO4)-O-V)(6)((CrO4)-O-VI), a disordered mixed-valence chromium compound exhibiting inversion twinning

The structure analysis of so-called 9CaO center dot 4CrO(3)center dot Cr2O3 proved it to be the title compound, decacalcium hexakis[chromate(V)] chromate(VI), with the simultaneous presence of unusual chromium oxidation states. The structure determination was carried out on a crystal that had inversion twinning. The (CrO4)-O-VI tetrahedron is situated on a threefold axis and is disordered over two possible orientations that share three O atoms, while the (CrO4)-O-V tetrahedra are in general positions and are ordered. The charge is balanced by Ca2+ cations, one of which is located on a threefold axis. The Ca2+ ions are coordinated by six, seven or eight O atoms. The compound is a significant phase in the CaO-CrOx system and its formation reduces the refractoriness of calcium-rich compositions in an oxidizing atmosphere