Synthesis of Drim-7,9(11)-diene and Its Hydroxylated Derivatives

This article describes a new efficient synthesis of drim-7,9(11)-diene and its hydroxylated derivates from drim-8-en-7-one. Reduction of this ketone with NaBO₄ in the presence of CeCl₃ · 7H₂O afforded regio- and stereoselectively drim-8-en-7β-ol in a high yield. Its dehydration with H₂SO₄ under mild conditions led to drim-7,9(11)-diene. Noncatalytic oxidation of drim-7,9(11)-diene with OsO₄ and the catalytic oxidation with the pair OsO₄–NMO gave, in a high yield, depending on conditions, driman-7β,8β,9α,11-tetraol or its mixture with drim-7-en-9α,11-diol and drim-9(11)-en-7α,8α-diol. Under optimal conditions the total yield of these diols reached 89%. The separate, noncatalytic oxidation of drim-7-en-9α,11-diol and of drim-9(11)-en-7α,8α-diol with OsO₄ afforded driman-7α,8α,9α,11-tetraol.     

Modified Pyridine-Substituted Coumarins: A New Class of Antimicrobial and Antitubercular Agents

Some new biologically potent coumarin derivatives 7a–f, 8a–f, and 9a–f bearing modified pyridine moieties (indeno[1,2-b]pyridine, 4-azaphenanthrene and benzofuro [3,2-b]pyridine) at the sixth position were designed and synthesized. All the synthesized compounds were assayed for their antimicrobial efficiency against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus niger. Most of the compounds showed appreciable antimicrobial activity against the tested strains. Compounds 8b, 8c, 9b, 9d, and 9f emerged as most proficient members of the series. The antitubercular activity for all the synthesized compounds was performed against Mycobacterium tuberculosis H37R_v. Compounds 8f, 9b, and 9f exhibited promising antitubercular activity. Consequently, synthesized derivatives were found to be worthy of further investigation.     

Synthesis and characterization of a dinuclear (Hedta)Ru(III) complex

A ruthenium(III) complex containing ethylenediaminetetraacetate (edta), [{Ru(Hedta)}₂(Pyz)]?·?8H₂O (1) (Pyz?=?pyrazine), has been synthesized by the reaction between K[Ru(Hedta)Cl]?·?1.5H₂O and pyrazine. The structure of the complex was determined by single X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1 with a?=?7.293(9)?Å, b?=?10.575(14)?Å, c?=?12.742(16)?Å, α?=?104.044(19)°, β?=?91.893(19)°, γ?=?93.35(2)°, Z?=?1. The product was also characterized by IR, UV-Vis, EPR spectrum and magnetic techniques.     

4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Penta(nitrato)lanthanate(III): Synthesis and Crystal Structure

A new complex salt, 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane penta(nitrato)lanthanate(III) (H₂(Crypt-222)]²⁺ · [La(NO₃)₅]^2?), is synthesized. Its crystal structure is studied using X-ray diffraction analysis (space group Pbcm, a = 9.517 Å, b = 13.358 Å, c = 24.585 Å, Z = 4; direct method, full-matrix least-squares in the anisotropic approximation, R = 0.039 for 4650 measured independent reflections). The [La(NO₃)₅]^2? complex anion lies on the m plane, and the 2 axis passes through the 2.2.2-cryptand dication with two protonated nitrogen atoms. The coordination polyhedron of the La³⁺ cation (coordination number 11) is a distorted octahedron with five bifurcated vertices, each containing two O atoms from the same NO ₃ ^? . ligand. The [La(NO₃)₅]^2? anions are joined into infinite polymer chains along the y axis through the NO ₃ ^? bridging ligand.     

A dimeric luminescent lanthanide complex [Eu(PAA)2(phen)(NO3)]2: hydrothermal synthesis,crystal structure and fluorescence

A lanthanide coordination complex [Eu(PAA)₂(phen)(NO₃)]₂ (PAA?=?phenylacetic acid, phen?=?1,10-phenanthroline) has been synthesized by the hydrothermal method. Single crystal X-ray diffractions show that it forms a dimeric molecular structure. The title complex crystallizes in the triclinic system, space group P 1, with lattice parameters a?=?8.9473(8)?Å, b?=?13.3659(12)?Å, c?=?13.4745(12)?Å, α?=?60.7590(10)°, β?=?89.5100(10)°, γ?=?71.9850(10)°, V?=?1317.3(2)?ų, D _c?= 1.675?Mg?m^?3, Z?=?1, F(000)?=?660, GOF?=?1.003, R ₁?=?0.0206, wR ₂?=?0.0575. The fluorescence excitation and emission spectra have been investigated.     

Complex formation of curium(III) with amino acids of different functionalities: L-threonine and O -phospho-L-threonine

The speciation of curium(III) with L-threonine and O-phospho-L-threonine was determined by time-resolved laser-induced fluorescence spectroscopy (TRLFS) at trace Cm(III) concentrations (3?×?10^?7?M). Curium species of the type M_pH_qL_r were identified in the L-threonine- and O-phospho-L-threonine system. These complexes are characterized by their individual luminescence spectra and luminescence lifetimes. The following formation constants were determined (a) for L-threonine: log?β₁₀₁?=?6.72?±?0.07, log?β₁₀₂?=?10.22?±?0.09, and log?β_1–22?=?(7.22?±?0.19) at ionic strength I?=?0.5?M and (b) for O-phospho-L-threonine: log?β₁₂₁?=?18.03?±?0.13 and log?β₁₁₁?=?14.17?±?0.09 at ionic strength I?=?0.154?M. Possible structures of the identified curium species are discussed on the basis of the luminescence lifetime measurements and the magnitude of the formation constants.     

New synthetic routes for the preparation of the triangular trinuclear clusters of tungsten-containing bromine atoms as terminal ligands: Structural characterization of [W3S4Br3(depe)3]PF6·0.5C7 H8 and [W3S4Br3(depe)3]Br·2CH3OH

Synthetic methods are reported for the preparation of compounds containing the trinuclear triangular cluster [W₃S₄Br₃(depe)₃[⁺. These involve reactions between WBr₅ and NaB(C₂ H₅)₃H or NaBH₄ as reducing agent in THF, and subsequent addition of methanolic solutions of NaHS and depe ligand. Both compounds, [W₃S₃Br₃(depe)₃]PF₆·0.5C₇H₈,1, and [W₃S₄Br₃(depe)₃]Br·2CH₃OH,2, are characterized by x-ray single crystal studies. Compounds1 and2 crystallize in space group \(P\bar 1\) . For1,a=10.427 (3) Å,b=15.415(4) Å,c=18.140(5) Å, α=79.36(2)°, β=73.59(2)°, γ=81.54(2)°, andV=2734.8(2) ų;R=0.050 and for 2a=10.491(3) Å,b=15.074(3) Å,c=18.246 Å, α=95.76(2)°, β=105.82(2)°, γ=98.18(2)°, andV=2718.4(3) ų;R=0.081. The two cations in1 and2 possess C₃ symmetry. The W-W distances are in the range 2.783?2.891 Å (for1) and 2.778?2.785 Å (for2) and the average W-Br distances in1 and2 are 2.616[2] Å and 2.594[4] Å, respectively. Each metal atom in the [W₃S₄Br₃(depe)₃]⁺ ions is attached to one capping sulfur atom, two bridging sulfur atoms, one bromine atom, and one chelating depe ligand. One P atom in depe ligand istrans to μ₃-S and the otherP atom istrans to a μ₂-S atom. UV-Vis and NMR spectra for these compounds are also reported.     

A 1D coordination polymer {Pb[C6H4(COO)2][phen]} n with strong blue fluorescent emission

The hydrothermal reaction of 1,3-dicyanobenzene, 1,10-phenanthroline (phen) and Pb(CH₃COO)₂ yields a new 1D coordination polymer, {Pb[C₆H₄(COO)₂][phen]} _n . The 1,3-benzenecarboxylate anion found in the final product was generated in situ during the synthesis by hydrolysis of 1,3-dicyanobenzene. X-ray diffraction shows that complex 1 crystallizes in the triclinic system, space group P 1, a?=?7.5442(2)?Å, b?=?9.7962(3)?Å, c?=?13.1505(4)?Å, α?=?69.739(2)?Å, β?=?80.597(2)?Å, γ?=?71.377(2)?Å, v?=?862.48(4)?ų, Z?=?2, D _c?=?2.124 Mg?m^?3. Complex 1 emits strong blue fluorescent light (λem(max)?=?482.4?nm) when excited by UV light in the solid state at room temperature.     

The crystal structures of α,ω-diaminoalkanecadmium(II) tetracyanonickelate(II)-aromatic molecule inclusion compounds. IV. (1,6-Diaminohexane)cadmium(II) tetracyanonickelate(II)-m-toluidine(1/1),-p-toluidine(1/1), and-2,4-xylidine(1/1) clathrates,and the coordination complex bis(p-toluidine) (1,6-diaminohexane)cadmium(II) tetracyanonickelate(II)

The crystal structures of the four title compounds have been analyzed by single crystal X-ray diffraction methods at room temperature. Three with a general formula Cd[NH₂(CH₂)₆NH₂]Ni(CN)₄·G (G=m-toluidine,Im;p-toluidine,Ip; and 2,4-xylidine,Ix) are the inclusion compounds of the respective aromatic molecules in the three-dimensional metal complex host (1,6-diaminohexane)cadmium(II) tetracyanonickelate(II). The remaining one is a coordination complex ofp-toluidine, bis(p-toluidine) (1,6-diaminohexane)cadmium(II) tetracyanonick-elate(II),II, Im, Ix, andII crystallize under similar experimental conditions;Ip is obtained using thep-toluidinemesitylene mixture at higher dilution than that used forII. Im crystallizes in the tri linic space group \(P\bar 1\) , witha=9.725(2),b=7.598(1),c=7.177(1) Å, α=90.44(1), β=98.80(1), γ=95.70(1)^o, andZ=1 (the final conventionalR=0.037 for 3526 reflections);Ip: monoclinic,P2/m,a=9.540(2),b=7.611(1),c=7.120(1) Å, β=100.95(1)^o, andZ=1 (R=0.027 for 1700 reflections);Ix: monoclinic,P2/m,a=9.628(2),b=7.613(1),c=7.122(1) Å, β=100.01(1)^o, andZ=1 (R=0.049 for 2704 reflections);II: monoclinic,P2₁/n,a=12.107(3),b=10.117(2),c=12.471(3) Å, β=113.67(2)^o, andZ=2 (R=0.037 for 2616 reflections). The structures ofIm, Ip andIx are similar to that of theo-toluidine inclusion compound of the same metal complex host. InII atrans pair of thep-toluidine molecules to the cadmium atom in the two-dimensional network formed by thecatena-μ-linkages of ?Cd?NH₂(CH₂)₆NH₂?Cd? and ?NC?Ni?CN?Cd?NC?Ni?CN?intersecting at each Cd atom; two cyanide groups of the tetracyanonickelate(II) moiety have free N-ends.