bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Variations in Tetrasilver(I) Complexes of Pyrazolate-bridged Compartmental N-Heterocyclic Carbene Ligands
Authors: Georgiou Maria , Wöckel Simone , Konstanzer Vera , Dechert Sebastian , John Michael , Meyer Franc
Published: February 2015

A set of pyrazole-bridged bis(imidazolium) compounds [H3L1]X2 - [H3 L4]X2 (L1 = 3,5-bis[1-(tert-butyl)imidazolium-1-ylmethyl]-1H-pyrazole; L2 = 3,5-bis[1-(tert-butyl)imidazolium- 1-ylmethyl]-4-phenyl-1H-pyrazole; L3 = 3,5-bis[1-(1-adamantyl)imidazolium-1-ylmethyl]-1Hpyrazole; L4 = 3,5-bis[1-(1-adamantyl)imidazolium-1-ylmethyl]-4-phenyl-1H-pyrazole; X = Cl−, BF4 − or PF6 −) has been prepared, and three compounds have been characterized by X-ray crystallography. The unique [H3L4][H2L4](PF6)3 features a dimeric face-to-face arrangement of two molecules due to the involvement of both the pyrazole-NH and the imidazolium C2H in hydrogen bonding. [H3L1]X2 - [H3L4]X2 serve as precursors for silver(I) complexes with compartmental pyrazolate-bridged bis(NHC) ligands. The complexes have been readily prepared by the Ag2O route and feature either the known [(L1−4)2Ag4]2+ or the new [(H2L1)4Ag4]8+ motif, depending on the solvent for the reaction (MeCN or acetone). [(H2L1)4Ag4](PF6)8 contains a central (pzAg)4 ring with pendant imidazolium side arms. Upon further reaction with Ag2O in MeCN it was found to undergo transformation to the corresponding [(L1)2Ag4](PF6)2. All complexes have been thoroughly studied by NMR spectroscopy in solution, and preliminary luminescence data of [(H2L1)4Ag4](PF6)8 have been recorded
Synthesis and Heat Resistance of Arylenedioxy-organosilanylene Polymers with Adamantane Units
Authors: Maehara Takayuki , Hashimoto Hiroshi , Ohshita Joji
Published: February 2015

Arylenedioxy-organosilanylene polymers with adamantane units in the backbone were prepared by Rh-catalyzed dehydrocoupling of bis(4-hydroxyphenyl)adamantanes with organohydrosilanes, and their heat resistance was evaluated by thermogravimetric analysis in nitrogen. Among these polymers, the highest Td10 (10% weight loss temperature) of 547 °C was achieved for polymer 2a prepared from 1,3-bis(4-hydroxyphenyl)adamantane and phenylsilane. Polymer 2a exhibited good heat resistance even in air with Td10 = 387 °C, and standing of the polymer at 150 °C for 8 h resulted in no evident weight loss
Stereochemistry of Disilanylene-containing Cyclic Compounds – Synthesis and Palladium-catalyzed Reactions of cis- and trans-3,4- Benzo-1,2-diisopropyl-1,2-dimethyl-1,2-disilacyclobut-3-ene
Authors: Naka Akinobu , Sakata Jun , Ikadai Junnai , Kawasaki Hiroyuki , Ohshita Joji , Miyazaki Eigo , Kunai Atsutaka , Yoshizawa Kazunari , Ishikawa Mitsuo
Published: February 2015

The synthesis and palladium-catalyzed reactions of cis- and trans-3,4-benzo-1,2-diisopropyl- 1,2-dimethyl-1,2-disilacyclobut-3-ene (1a and 1b) are reported. Their reactions with diphenylacetylene in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) proceeded with high stereospecificity to give cis- and trans-5,6-benzo-1,4-diisopropyl-1,4-dimethyl- 2,3-diphenyl-1,4-disilacyclohexa-2,5-diene, 2a and 2b, in 95% and 93% yield, respectively. Similar palladium-catalyzed reactions of 1a and 1b with monosubstituted acetylenes, such as 1-hexyne, tert-butylacetylene, phenylacetylene, and trimethylsilylacetylene, also proceeded stereospecifically to afford the respective cis- and trans-5,6-benzo-1,4-disilacyclohexa-2,5-dienes, 3a - 6a and 3b - 6b, in excellent yields and as the sole products. The palladium-catalyzed reaction of 1a with styrene gave a mixture consisting of two stereoisomers, cis-2- and trans-2-phenyl-substituted 5,6- benzo-(r-1),cis-4-diisopropyl-1,4-disilacyclohex-5-ene 7a and 8a in a ratio of 5 : 3 in 72% combined yield, while the reaction of styrene with 1b afforded two stereoisomers, 7b and 8b, in a ratio of 2 : 1 in 80% combined yield. With 1-hexene, 1a gave two stereoisomers, 5,6-benzo-cis-2-(nbutyl)-( r-1),cis-4-diisopropyl- and 5,6-benzo-trans-2-(n-butyl)-(r-1),cis-4-diisopropyl-1,4-dimethyl- 1,4-disilacyclohex-5-ene, 9a and 10a, in a ratio of 1 : 1 in 70% combined yield. A similar reaction of 1b with 1-hexene produced 5,6-benzo-cis-2-(n-butyl)-(r-1),trans-4-diisopropyl-1,4-dimethyl-1,4- disilacyclohex-5-ene in 81% yield and as a single isomer
Improved Conversion of Dihydrooroidin to Oroidin and Ugibohlin
Authors: Moldovan Rareş-Petru , Lindel Thomas
Published: February 2015

Dihydrooroidin was converted to the marine natural product oroidin in 75% overall yield by chlorination of the 2-aminoimidazole unit in DMF, followed by dehydrochlorination. The natural product ugibohlin was synthesized for the first time by ring opening of dibromoisophakellin, which was obtained in a quantitative manner by heating the free base of dibromophakellin in neutral aqueous solution
Novel Betaines of the Hexaalkylguanidinio-carboxylate Type
Authors: Walter Matthias , Maas Gerhard
Published: February 2015

Betaines 7a, b and 8a, b have been prepared from 3- and 4-piperidinecarboxylic acid and N,N,N',N'-tetraalkyl-chloroformamidinium chlorides via the corresponding methyl esters. These betaines are highly hygroscopic, thermally very stable, and, with the exception of 7b, have rather low melting points. They undergo a surprisingly facile alkaline cleavage of the hexaalkylguanidinium moiety. They react with dichloromethane by a twofold nucleophilic substitution to form methylene dicarboxylates such as 11. TheNMR (1H, 13C) data of betaines 7 and 8 are discussed
AquaGroupAcidity in Complexes of theType trans-[Pt(NH3 )2(L)(H2O)]2+ (with L = Substituted Pyridines). Linear, yetWeak Dependence of pKa of the Aqua Ligand from L Basicity
Authors: Galstyan Anzhela , Shen Wei-Zheng , Lippert Bernhard
Published: February 2015

The pKa of the aqua ligand in complexes of the type trans-[Pt(NH3)2(L)(H2O)]n+ depends on the nature of the ligand trans to H2O, as expected. With L = NH3 or NH2R and n = 2, the pKa is around 6.0 - 6.4.With L = N-heterocyclic ligands generally higher acidities of the aqua ligands are observed, with pKa values being in the range of 4.7 - 5.4. These values are between those for L = H2O, n = 2 (4.4) and L = Cl−, n = 1 (5.7). For differently substituted pyridine ligands L a linear relationship exists between the pKa of the H2O ligand and the basicity of the heterocyclic ligand L, which is relatively weak, however
Syntheses and Structures of Silver(I) and Palladium(II) Complexes with Ferrocenyl-phosphonodithiolate Ligands
Authors: Wang Xi-Ying , Shi Hua-Tian , Ma Qing , Zhang Qian-Feng
Published: February 2015

Coordinative interaction of [Ag(PPh3)2NO3] or [Pd(MeCN)2Cl2] with in situ-prepared Na[FcP- (OR)S2] afforded 1 : 1 products [FcP(OR)S2Ag(PPh3)2] (R = Me 1, n-Pr 2) or the 1 : 2 product [{FcP(OMe)S2}2Pd] (3). Complexes 1 - 3 were characterized by elemental analysis, mass spectrometry, NMR (1H, 31P) and IR spectroscopy, as well as by X-ray crystallography. The distorted tetrahedral silver(I) coordination led to non-planar and distorted four-membered AgS2P rings in 1 and 2, whereas the square-planar palladium(II) coordination resulted in four-membered co-planar PdS2P rings in 3
Brominated Metabolites from the Marine Red Alga Laurencia similis
Authors: Li Chun-Shun , Li Xiao-Ming , Cui Chuan-Ming , Wang Bin-Gui
Published: February 2015

One new sesquiterpenoid, aristolan-1α-bromo-9β ,10β -epoxide (1), and one new indole alkaloid, 2,5-dibromo-N-methylindole (2), along with six sesquiterpenes and indoles were identified from the marine red alga Laurencia similis. Their structures were established on the basis of spectroscopic methods
Formation of the Complexes [Fe(H2BDI)3]X2 and [CpCr(H2BDI)2]X2 (X =OTf) fromthe Unusual Reactions of Benzil-bis(trimethylsilyl)diimine with CpML2Cl (M = Fe, L = CO; M = Cr, L = NO)
Authors: Haque Nadera , Neumann Bernd , Lorenz Ingo-Peter
Published: February 2015

The reaction of CpML2Cl (M = Fe, L = CO; M = Cr, L = NO) with benzil diimine (H2BDI) (2) derived from benzil-bis(trimethylsilyl)diimine (Si2BDI) (1) in a 1 : 3 and 1 : 2 molar ratio in the presence of excess AgO3SCF3 (= AgOTf) resulted in the formation of the new cationic tris- and bisbenzildiimine complexes [Fe(H2BDI)3]X2 (3) and [CpCr(H2BDI)2]X2 (X = OTf) (4), respectively. The addition of AgO3SCF3 is necessary in both cases to abstract chloride. Unusual in the first case is the total replacement of ligands of CpFe(CO)2Cl and in the second case the oxidation of Cr(0) to Cr(III) leading to the formation of complexes 3 and 4, respectively, with the neutral bidentate diimine ligand 2. Complexes 3 and 4 were fully characterized by their IR, mass, 1H- and 13C-NMR spectra, as well as elemental analyses. The molecular structures determined by X-ray diffraction studies reveal a distorted octahedral tris-chelate configuration in 3 and a pseudo-tetragonal pyramidal one in 4.
Tetra(alkynyl)silanes, a 3,6-Disila-triyne, a 3,6,9-Trisila-tetrayne, a 1,3,4,6-Tetrasiladiyne, and Bis(trimethylstannyl)ethyne. Molecular Structures and Solid-state NMR Studies
Authors: Wrackmeyer Bernd , Khan Ezzat , Badshah Amin , Molla Elias , Thoma Peter , Tok Oleg L. , Milius Wolfgang , Kempe Rhett , Senkere Jürgen
Published: February 2015

The molecular structures of three alkynylsilanes, tetrakis(ethynyl-p-tolyl)silane, 3,3,6,6,-tetramethyl- 3,6-disila-triyne, 3,3,6,6,9,9,-hexamethyl-3,6,9-trisila-tetrayne, and of bis(trimethylstannyl)- ethyne have been determined by X-ray diffraction. The same alkynylsilanes, and in addition 1,2- bis(trimethylsilylethynyl)-1,1,2,2-tetramethyldisliane, were studied by solid-state 13C and 29Si MAS NMR spectroscopy. The results of these measurements were compared with crystallographic evidence and also with relevant solution-state NMR data.
Synthesis and Crystal Structure of Lead(II) Thenoyltrifluoroacetonate Complexes with Substituted 2,2' -Bipyridines: Interplay of Intermolecular Interactions in Crystals
Authors: Marandi Farzin , Nikpey Zahra , Goh Jia Hao , Fun Hoong-Kun
Published: February 2015

Three substituted 2,2'-bipyridine adducts of lead(II) thenoyltrifluoroacetonate, [Pb(4,4'-dm-2,2’- bpy)(ttfa)2]2, 1, [Pb(5,5' -dm-2,2’-bpy)(ttfa)2]2, 2, and [Pb(4,4'-dmo-2,2’-bpy)(ttfa)2], 3, (4,4’ -dm- 2,2’-bpy, 5,5’-dm-2,2’-bpy, 4,4’-dmo-2,2’-bpy and ttfa are the abbreviations for 4,4’-dimethyl-, 5,5’-dimethyl-, and 4,4’-dimethoxy-2,2’-bipyridine, and thenoyltrifluoroacetonate, respectively) have been synthesized, characterized by elemental and thermal analysis, IR and 1H- and 13C-NMR spectroscopy, and studied by X-ray crystallography. The supramolecular features in these complexes are guided/controlled by weak directional intermolecular interactions.
Synthesis and Structural Characterisation of a Hexanuclear TiIV Compound Ti6(μ2-O)2(μ3-O)2(μ2-OC4H9)2(OC4H9)6(OOCCHCl2)8
Authors: Pandey Ashutosh , Pandey Anjana , Singh Sadhana , Mayer Peter , Parakd Wolfgang J.
Published: February 2015

Titanium tetra-butoxide was reacted with dichloroacetic acid in 1 : 1 and 1 : 2 molar ratio in toluene at ambient temperature to give, respectively, the mono- and bis-substituted products Ti(OBun)3(OOCCHCl2) and Ti(OBun)2(OOCCHCl2)2 (1) in quantitative yields. However, when a toluene solution of compound 1 was kept at −20 ◦C for crystallisation, colourless crystals of a hexanuclear complex Ti6(μ2-O)2(μ3-O)2(μ2-OC4H9)2(OC4H9)6(OOCCHCl2)8 (2) were obtained. The basic skeletal arrangement of compound 2, as revealed by X-ray diffraction, can be described as corner-removed, inversion-related [Ti-O]4 cubes with face-linked oxide bridges.
Syntheses, Structures and Second-order Nonlinear Optical Behavior of (E)-N-(4-Nitrobenzylidene)-3,4-dimethylaniline and (E)-N-(3-Nitrobenzylidene)-3,4-dimethylaniline
Authors: Unver Hüseyin , Karakas Aslí , Durlu Tahsin Nuri
Published: February 2015

(E)-N-(4-Nitrobenzylidene)-3,4-dimethylaniline (1) and (E)-N-(3-nitrobenzylidene)-3,4-dimethylaniline (2) have been synthesized, and their crystal structures have been determined by X-ray diffraction analysis. Linear optical characteristics have been evaluated experimentally using UV/Vis spectroscopy and theoretically using the configuration interaction (CI) method. The maximum onephoton absorption (OPA) wavelengths of the studied compounds are shorter than 450 nm, giving rise to good optical transparency in the visible and near IR regions. The ab initio quantum-mechanical calculations (finite field second-order Møller-Plesset perturbation theory) of the investigated molecules have been carried out to compute the electric dipole moment (μ) and the first hyperpolarizability (β ) values. The ab initio results suggest that the title compounds might have microscopic second-order nonlinear optical (NLO) behavior with non-zero values.
Five-coordinate Zinc(II) Complexes Containing Sterically Demanding Bio-mimetic N3S2 Ligands. Syntheses, Characterization and DFT Calculations
Authors: Shaban Shaban Y. , Puchta Ralph , Eldik Rudi van
Published: February 2015

In search of complexes having [ZnN3S2] cores in the monomeric form with trans-thiolate donor atoms, new sterically demanding tri- and pentadentate ligands containing biomimetic N3S2 cores have been synthesized. The reaction of bis(2-mercapto-3,5-di-tert-butylaniline)zinc(II) with 2,6- diacetylpyridine leads to the formation of the zinc imine [Zn(pytBuN2Me2S2)] (3) which is stable and can be isolated and characterized in the solid state. Complex 3 can be converted to the zinc amine function [Zn(pytBuN2H2Me2S2)] (5) without losing the metal center using NaBH4 in methanol solution. On the other hand, complex 3 can be demetallated in an acidic medium to give the tridentate bis-benzothiazoline ligand 4. Alternatively, ligand 4 can be obtained via condensation of 3,5-di-tertbutylmercaptoaniline with 2,6-diacetylpyridine in a 2:1 molar ratio. Opening the bis-benzothiazoline ligand 4 either by reduction with NaBH4 in methanol or by zinc acetate leads to the formation of the pentadentate dithiole-amine ligand pytBuN2H2Me2S2-H2 (6), and the zinc imine complex 3, respectively. Ligand 6 can also be obtained via demetallation of the zinc amine complex 5 in acidic medium. All compounds have been characterized using spectroscopic methods and elemental analysis, and also by using DFT (B3LYP/6-31G∗) calculations in combination with experimental NMR data.
Dinukleare cofaciale Metallocyclen mit Kupfer und Nickel: Synthese und Struktur / Binuclear Cofacial Metallocycles of Copper and Nickel: Synthesis and Structure
Authors: Bauer Walter , Hampel Frank , Maid Harald
Published: February 2015

The synthesis and characterization of six binuclear copper(II) and nickel(II) metallocycles [M2(L1−3)2] 7, starting from pyridyl-, phenyl- or naphthyl-spacered vinylogous amide ligands H2L 6, are reported. [Cu2(L3)2] 7e forms an inclusion compound [Cu2(L3)2(Py)2] 8 with two molecules of pyridine bound to the copper centers inside the cage. The structures of the metallocycles 7a, 7d, 8 were determined by X-ray diffraction analyses.
Changing the Overall Shape of Heterodinuclear Helicates via Substitution of Acylhydrazones by Tosylhydrazones
Authors: Albrecht Markus , Latorre Irene , Liu Yufeng , Fröhlich Roland
Published: February 2015

Heterodinuclear helicate-type complexes are formed from acyl and tosyl hydrazone-substituted catechol ligands. Due to the different geometry of the carboxylate compared to the sulfonate unit, different overall structures are observed for the complexes. The acylate results in the formation of a cylindrical triple-stranded system, while in the tosylate the pendant substituents fold back and form a more condensed structure.
Platinum Complexes with Picoline-functionalized Benzimidazolin-2-ylidene Ligands
Authors: Jahnke Mareike C. , Hahn Ekkehardt
Published: February 2015

The dicarbene platinum complexes of the type [Pt(L)2]Br2 [5]Br2 - [8]Br2 (L = N-alkyl-N´- picolylbenzimidazolin-2-ylidene) have been prepared by two different methods. The in situ deprotonation of picoline-functionalized benzimidazolium salts 1 - 4 with platinum acetylacetonate gave the platinum complexes [5]Br2 - [8]Br2 in good yields. Complex [8]Br2 has also been obtained by a ligand transfer reaction from the silver dicarbene complex [9][AgBr2]. Attempts to cystallize [8]Br2 obtained from the carbene transfer reaction led to the isolation of the previously undetected monocarbene complex [Pt(Cl)2L] (10) which contains only one picoline-functionalized carbene ligand coordinating in a chelating fashion to the metal center
Mineralization of Phenol and 4-Chlorophenol Induced by Visible Light and Assisted by Semiconducting β-Bi2O3
Authors: Eberl Joachim , Kisch Horst
Published: February 2015

Intensely yellow β -bismuth trioxide in the form of about 41 nm large crystallites has been prepared by thermal decomposition of (BiO)2CO3 at 400 ◦C. From the band gap energy of 2.3 eV obtained under the assumption of an indirect band-to-band transition and the quasi-Fermi level of −0.28±0.02 V (vs. NHE) a valence band edge position of 2.02 V is calculated. This semiconducting oxide assists a Vis light (λ ≥455 nm) aerial mineralization of the aqueous model pollutants phenol and 4-chlorophenol exhibiting maximum rates at a bismuth oxide concentration of 2.0 g L−1. In the absence of oxygen no degradation occurs indicating that β -Bi2O3 does not act as oxidizing agent. The mineralization suffers from photocorrosion of β -Bi2O3 generating a mixture of α-Bi2O3 and various bismuth carbonates as observed upon multiple use of the oxide in the mineralization of phenol.
Electron Density of Corannulene from Synchrotron Data at 12 K, Comparison with Fullerenes
Authors: Grabowsky Simon , Weber Manuela , Chen Yu-Sheng , Lentz Dieter , Schmidt Bernd M. , Hesse Malte , Luger Peter
Published: February 2015

The electron density of corannulene, C20H10, was derived from a high-resolution synchrotron data set (sinθ /λ = 1.11 Å−1) measured at 12 K and from an ab-initio geometry optimization on the B3LYP/6-31G* level. A full topological analysis yielded atomic and bond-topological properties which were compared between experimental and theoretical findings and, as far as steric congruences exist, with corresponding fragments of the fullerene C70. For the four different types of C-C bonds in corannulene, a rather close bond-order range between 1.3 and 1.8 was found indicating a considerable delocalization in this molecule. As was already found earlier in fullerene cages, the deformation density on the C-C bonds is not arranged symmetrically. There is more density located outside than inside the corannulene bowl so that in total, charge accumulation is shifted to the outer surface of the molecule. The electrostatic potential suggests an H...π stacking in the crystal which directs the relative orientation of the two crystallographically independent corannulene molecules. The positively charged rim region of one molecule is oriented almost perpendicular to the negative potential region at the bottom of a second molecule.
Organic-Inorganic Hybrid Compounds Based on Lead Halide Units: Preparation from Melts and through Grinding Effects
Authors: Papavassiliou George C. , Mousdis George A. , Anyfantis George C.
Published: February 2015

Organic-inorganic hybrid compounds based on lead halide units of the formula (CH3NH3)2- (CH3C6H4CH2NH3)2Pb3(BrxY1−x)10 (Y = Cl, I) were prepared from melts, and their optical absorption as well as photoluminescence spectra, before and after grinding the compounds, were investigated. The luminescence of the materials after grinding is strong and is observed with naked eye. By changing the mole fraction (x), the strong photoluminescence in the range from ca. 400 nm to ca. 600 nm could be tuned. These effects indicate that the hybrid compounds are promising materials for potential applications.
Single-Crystal X-Ray Diffraction Study of Na[OCN] at 170 K and its Vibrational Spectra
Authors: Reckeweg Olaf , Schulz Armin , Leonard Brian , DiSalvo Francis J.
Published: February 2015

The unit cell of Na[OCN] has been determined on single crystals at 170 K to have rhombohedral symmetry with the lattice parameters a = 356.79(10) and c = 1512.3(5) pm (hexagonal setting). According to the only model for which a converging refinement could be achieved, Na[OCN] crystallizes isopointal to β -NaN3 in the space group R¯3m (no. 166, Z = 3) with a statistically disordered [OCN]− anion. The positional coordinates and displacement parameters could not be separated for the O and N end atoms of the triatomic anion. The vibrational spectra show the frequencies typical for an [OCN]− moiety with Fermi resonance between the 2δ and the νsym vibrations for which the undisturbed frequencies were calculated.
Li13.7Rh8Si18.3 – A Non-Centrosymmetric Variant of the R-Phase Structure
Authors: Dinges Tim , Hoffmann Rolf-Dieter , Pöttgen Rainer
Published: February 2015

The silicide Li13.7Rh8Si18.3 was synthesized from the elements in a sealed niobium ampoule at 1370 K followed by slow cooling. The sample was studied by powder and single-crystal X-ray diffraction. Li13.7Rh8Si18.3 crystallizes with a non-centrosymmetric occupancy variant of the R-phase structureMg32( Al, Zn)49: I23, a = 1306.9(2) pm, wR2 = 0.0447, 1286 F2 values, and 53 variables. Striking structural motifs of the Li13.7Rh8Si18.3 structure are M12 icosahedra and M60 buckyball-type clusters (M = Si + Rh), both partially built up from mixed-occupied sites.
N-Dimethylphosphinoyl-substituted Aminomethanephosphonic Acids
Authors: Lachkova Victoria , Varbanov Sabi , Frank Walter , Keck Helmut
Published: February 2015

Three new N-phosphinoyl-substituted aminomethanephosphonic acids have been synthesized and characterized: dimethylphosphinoylmethyl-imino-bis(methanephosphonic acid) (1), [3-(dimethylphosphinoyl)-propyl]-imino-bis(methanephosphonic acid) (2), and N-benzyl-Ndimethylphosphinoylmethyl- aminomethanephosphonic acid (3). The latter was isolated as a hydrochloride 3 ・ HCl. The acids have been prepared via Moedritzer-Irani reaction from the corresponding dimethylphosphinoyl-substituted primary and secondary aliphatic amines. Their structures have been confirmed by elemental analysis, IR, 1H, 31P{1H}, 13C{1H} NMR spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction.
Synthese und Eigenschaften 3,6-diaminosubstituierter 1,2,4-Triazin-5(2H)-one / Synthesis and Properties of 3,6-Diamino-substituted 1,2,4-Triazin-5(2H)-ones
Authors: Geffken Detlef , Köllner Maria Anna
Published: February 2015

The ultrasound-promoted cyclocondensation of N1-amino-N2-arylmethyl- (or aryl-) guanidines 2 with ethyl 2-amino-2-thioxoacetate furnished novel 3,6-diamino-substituted 1,2,4-triazin-5(2H)- ones 4 in moderate to high yields. The acylation of compounds 4 occurred regioselectively at ring position 2, presumably favoured by the formation of an intramolecular hydrogen bond. In accordance with this assumption, the acetylation of 6-amino-3-[benzyl(methyl)amino]-1,2,4-triazin-5(2H)-one (9) did not afford the 2-acetyl derivate 11 but rather the 6-acetamido derivative 10.
Synthesis and Antimicrobial Evaluation of Some New 2-(6-Oxo-5,6- dihydro[1,3]thiazolo[3,2-b]-2-aryloxymethyl-1,2,4-triazol-5-yl)-Narylacetamides
Authors: Lobo Prajwal L. , Poojary Boja , Manjunatha Kumsi , Kumari Nalilu Suchetha
Published: February 2015

A series of 2-(6-oxo-5,6-dihydro[1,3]thiazolo[3,2-b]-2-aryloxymethyl-1,2,4-triazol-5-yl)-Narylacetamides 6 were synthesized in good yield by condensing 5-aryloxymethyl-4H-1,2,4-triazole- 3-thiol 5 with various substituted N-phenyl-maleimides in acetic acid media. The newly synthesized compounds were characterized by spectral data and tested for their in vitro antibacterial and antifungal activity against a variety of microorganisms.
Polystachyasaponin with Adjuvant Activity from Entada polystachya
Authors: da Silva Bernadete P. , Parente José P.
Published: February 2015

A new complex triterpenoid saponin, polystachyasaponin, was isolated from leaves of Entada polystachya (L.) DC. (Leguminosae) by using chromatographic methods. Its structure was established as 15,16-dihydroxy-3-[[O-β -D-xylopyranosyl-(1→2)-O-α-L-arabinopyranosyl-(1→6)-2- (acetylamino)-2-deoxy-β -D-glucopyranosyl]oxy]-(3β ,15α,16α)-olean-12-en-28-oic acid O-D-apio- β -D-furanosyl-(1→3)-O-β -D-xylopyranosyl-(1→2)-O-[β -D-glucopyranosyl-(1→4)]-6-O-[(2E,6R)- 6-hydroxy-2,6-dimethyl-1-oxo-2,7-octadienyl]-β -D-glucopyranosyl ester. Structural elucidation was performed using detailed analyses of 1H and 13C NMR spectra including 2D NMR spectroscopic techniques and chemical conversions. The hemolytic activity of the saponin was evaluated using in vitro assays, and its adjuvant potential on the cellular immune response against ovalbumin antigen was investigated using in vivo assays.
A New Taxane from the Hard Wood of Taxus cuspidata
Authors: Yu Shu-Hong , Zhang Man-li , Wang Yu-Fang , Huo Chang-Hong , Gu Yu-Cheng , Shi Qing-Wen
Published: February 2015

A new taxoid metabolite with an unusual double bond between C-13 and C-14 was isolated from the methanol extract of the hard wood of Taxus cuspidata. The structure was established as 2α,5α,7β ,9α,10β ,13β -hexaacetoxy-11β -hydroxyl-19β -benzoxytaxa-4(20),13-dien- 12,16-epoxide (1), named 5,13-diacetyltaxinine M-13-enol, on the basis of spectral analysis including 1H NMR, 13C NMR, HMQC, HMBC, NOESY and confirmed by HR-FAB-MS.
Einfaches System, vielfältige Strukturen: Eine Neuuntersuchung der (Amin)halogenidosilber(I)-Komplexe/ A Simple System with many Structural Variants: A Reexamination of (Amine)halogenidosilver(I) Complexes
Authors: Wölper Christoph , Polo Bastardés María Dolores , Dix Ina , Kratzert Daniel , Jones Peter G.
Published: February 2015

We report the structures of nineteen new amine silver halide complexes, some of them featuring previously unknown structure types, stoichiometries (such as L4Ag5X5) and coordination numbers. Known structures have been included and analysed for non-classical hydrogen bonds. We have identified three important factors for the formation of certain structure types. First, Ag-X bonds that form a central framework, typically staircase-shaped. Secondly, hydrogen bonds or other secondary interactions competing with these leading to a weakening or disappearance of some of the central Ag-X bonds. Finally, the polarity of the substituent at nitrogen and the silver halides influence the stoichiometry of the complex.
Antimicrobial Alkaloids from the Tubers of Stephania succifera
Authors: Yang De-Lan , Mei Wen-Li , Wang Hui , Dai Hao-Fu
Published: February 2015

Chemical investigation of the EtOH extract from the tubers of Stephania succifera collected in Hainan Province of China resulted in the isolation of the two new alkaloids Cepharanone D (1) and N-formyl-asimilobine (2), and a known alkaloid, N-formyl-annonain (3). Their structures were elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR). The antimicrobial activities of the three compounds were also investigated.
Synthesis and Modification of Substituted 2-Azaanthraquinones
Authors: Welzel Thomas , Weiß Dieter , Beckert Rainer , Görls Helmar
Published: February 2015

The cycloaddition-ring transformation reaction sequence of pyrido[1,2-a]pyrazines with substituted naphthoquinones furnished a series of new highly substituted azaanthraquinones. Whereas monosubstituted naphthoquinones were normally leading to two regioisomeric products, in some cases a preference for only one regioisomer was observed. The amino derivative 3b which was isolated as the main product proved to be suitable for further modifications at the primary amino group. The derivatives obtained possess groups capable of connecting the molecule with other substructures for applications as functional dyes. The newly synthesized azaquinones show strong and very broad absorptions between 400 and 600 nm in their UV/Vis spectra
Orthoamide, LXIX [1]. Beiträge zur Synthese N,N,N´,N´,N´´-peralkylierter Guanidine und N,N,N´,N´,N´´䞲,N´´-persubstituierter Guanidiniumsalze / Orthoamides, LXIX [1]. Contributions to the Synthesis of N, N, N´, N´, N´-peralkylated Guanidines and N, N, N´, N´, N´´, N´´-persubstituted Guanidinium Salts
Authors: Kantlehner Willi , Mezger Jochen , Kreß Ralf , Hartmann Horst , Moschny Thorsten , Tiritiris Ioannis , Iliev Boyan , Scherr Oliver , Ziegler Georg , Souley Bahari , Frey Wolfgang , Ivanov Ivo C. , Bogdanov Milen G. , Jäger Ulrich , Dospil Günther , Viefhaus Tillmann
Published: February 2015

N, N, N´, N´-Tetraalkyl-chloroformamidinium chlorides 6 are prepared from N, N, N´, N´-tetraalkylureas 5 and phosgene in acetonitrile. The iminium salts 6 react with primary and secondary amines in the presence of triethylamine to give N, N, N´, N´, N´´-pentasubstituted and N, N, N´, N´, N´´, N´´- hexasubstituted guanidinium salts 7 and 8, respectively, Treatment of the guanidinium salts 7 with sodium hydroxide in excess affords the N, N, N´N´, N´´-pentasubstituted guanidines 9a - 9aa. Additionally, the N, N, N´, N´, N´´-pentasubstituted and N, N, N´, N´, N´´, N´´-hexasubstituted guanidinium salts 7l´, 7p´ and 8a - c can be obtained from the reaction mixtures by addition of stoichiometric amounts of sodium hydroxide. A modified method is described for the preparation of guanidinium salts possessing dialkylamino substituents consisting of two long-chain alkyl groups (>C14). Some guanidines 9 were alkylated with allyl chloride and bromide, ethyl bromide, butyl bromide, benzyl bromide and chloride, dimethyl sulfate, diethyl sulfate, and methyl methansulfonate to give the corresponding guanidinium salts 11 - 15. By alkylation of the N, N, N´, N´, N´´-pentasubstituted guanidine 9v with triethyloxonium tetrafluoroborate the guandinium tetrafluoroborate 16a is accessible. N-Functionalized guanidinium salts 17 - 18a - c result from the reaction of N, N, N´, N´, N´´-pentasubstituted guanidines with ethyl bromoacetate and bromoacetonitrile, respectively, and subsequent anion exchange with sodium tetraphenylborate. N, N, N´, N´-Tetramethylguanidine (21) adds to ethyl acrylate to give the labile guanidine 22, which forms the guanidinium salt 23a on treatment with methyl iodide. Zwitterionic guanidinium salts 25 result, when N, N, N´, N´, N´´-pentasubstituted guanidines are treated with sultones 24.
Review. Solvothermal Synthesis and Structure of Chalcogenidoarsenate Anions
Authors: Kromm Anna , Almsick Tobias van , Sheldrick William S.
Published: February 2015

A rich variety of chalcogenidoarsenate anions and ligands have been prepared under mild solvothermal conditions in strongly polarizing solvents such as water, methanol and amines in the temperature range 100 - 200 ◦C. This review covers synthetic and structural aspects of such species ASxEy
z− with particular emphasis being placed on the trends and differences observed for E = S, Se, Te and on developments within the past decade. These include the preparation of quaternary Main Group element chalcogenidoarsenates(III) such as Cs3AsGeSe5 and polymeric selenidoarsenates(II, III) such as Cs2As4Se6. A currently expanding area of interest involves the employment of transition metal-polyamine or -polyimine fragments such as {Mn(tren)}2+ or {Mn(terpy)}2+ as structuredirecting agents. The metal atoms of such cations can be connected to the terminal chalcogen atoms of oligomeric or polymeric anions AsxEy z− to prevent their further condensation or can be directly incorporated into anionic or neutral networks when at least two free coordination sites are available in the fragment. This strategy has led to the characterization of novel ligands including cyclo- [As4S8]4−, As2Se6
2−, As2Se6
4− and 1
∞[As4Se7
2−]. The syntheses and structures of the new compounds Cs5As5Se9 and Cs[{Mn(trien)}(AsSe4-K2Se)] ・CH3OH are also presented. Whereas the former phase contains infinite selenidoarsenate(II,III) chains 1
∞[As5Se9
5−], the [{Mn(trien)}(AsSe4)]− anion of the latter compound represents the first example of a transition metal-containing ternary selenidoarsenate( V)
Review. Solvothermal Processes: Definition, Key Factors Governing the Involved Chemical Reactions and New Trends
Authors: Demazeau Gérard
Published: February 2015

Solvothermal processes are defined, and the different domains of applications are described. The main physico-chemical factors playing a key role in such processes are then analyzed. The trends characterizing the current development of solvothermal processes are outlined
Review. Non-aqueous Sol-Gel Routes to Metal Oxide Nanocrystals under Solvothermal Conditions: Review and Case Study on Doped Group IV Metal Oxides
Authors: Pucci Andrea , Pinna Nicola
Published: February 2015

Over the last decade, the number of publications concerning the non-aqueous sol-gel synthesis of metal oxide nanostructures has rapidly increased, as this method affords an immense variety of sizes and shapes of the products. This review highlights the versatility of non-aqueous sol-gel routes, under solvothermal conditions, to metal oxide and hybrid materials. In particular, the easier control over the reaction kinetics, compared to aqueous methods, allows to better match the reactivity between metal oxide precursors. This permits to produce complex multimetal and doped oxides at low temperature, as it is discussed in detail for the case of doped group IV metal oxides
The Influence of Synthesis Parameters on FeO(OH) / Fe2O3 Formation by Hydrothermal Techniques
Authors: Popescu Madalina , Piticescu Roxana , Vasile Eugeniu , Taloi Dragos , Petriceanu Mirela , Stoiciu Maria , Badilita Viorel
Published: February 2015

In this paper, a hydrothermal method of high-pressure and low-temperature synthesis conditions is presented as a simple single-step technique to obtain crystalline nanoparticles of iron oxides. The aim of this work has been to demonstrate the influence of the main synthesis parameters on the formation of nanosized Fe2O3 particles using statistical methods and to establish the most significant effects. Based on mathematical pre-modeling calculations, the best reaction conditions for the hydrothermal process have been chosen, and controlled crystalline nanostructures of iron oxides could be prepared
Penta-, Hepta- und Oktaiodid-Anionen in Salzen mit Erdalkalimetall-Kronenether-Kationen / Penta-, Hepta-, and Octaiodide Anions in Salts with Alkaline Earth Metal Crown Ether Cations
Authors: Walbaum Christine , Pantenburg Ingo , Meyer Gerd
Published: February 2015

Salts of alkaline earth metal cations sequestered in dibenzo-18-crown-6 (Db18c6) and benzo-15- crown-5 (B15c5), respectively, with I5
−, I7
− and I8
2− as the anions, have been synthesized and their crystal structures determined by single-crystal X-ray diffraction. [Ca(Db18c6)(H2O)3](I5)2- (Db18c6)(H2O) (1): monoclinic, P21 (no. 4), a = 1322.1(2), b = 1849.1(2), c = 1344.0(2) pm, β = 114.70(1)◦, V = 2985.2(6) × 106 pm3, Z = 2; [Sr(B15c5)2](I7)2 (2): triclinic, P1 (no. 2), a = 973.9(5), b = 1244.0(5), c = 1293.3(5) pm, α = 115.28(1), β = 90.18(1), γ = 104.57(1)◦, V = 1360.2(10) × 106 pm3, Z = 2; [Ba(Db18c6)2]I8 (3): orthorhombic, Pbcn (no. 60), a = 1452.0(2), b = 1924.6(2), c = 1912.1(2) pm, V = 5343.3(10) × 106 pm3, Z = 4. Compound 1 contains two crystallographically independent V-shaped pentaiodide anions, I5 −, which are linked to dimers by weak interionic contacts. The unusual heptaiodide anion, I7
−, in 2 can be described as a V-shaped pentaiodide unit, which is connected to a slightly widened iodine molecule to give the rare Z form. Secondary bonding distances lead to almost planar ten-membered iodine rings, which are connected through common edges to form ribbons with staircase-like folding. 3 is built of sandwich-like cations and centrosymmetric octaiodide anions, I8
2−. An inspection for secondary contacts reveals that the iodine substructure of 3 consists of essentially isolated octaiodide units.
Two New Hemidirected Lead(II) Complexes: [Pb(pcih)(bha)] and [Pb(pcih)(NO3)]
Authors: Li Dong-Qing , Liu Xing , Zhou Jian
Published: February 2015

Two new lead(II) complexes [Pb(pcih)(bha)] (1) and [Pb(pcih)(NO3)] (2, Hpcih = 1,4-bis(3-pyridyl)- 2,3-diazo-1,3-butadiene, Hbha = 2-hydroxybenzoic acid) have been synthesized by solvothermal methods and structurally characterized. The single-crystal X-ray data show that the coordination spheres of the Pb2+ ions in 1 and 2 are hemidirected with stereochemically active electron lone pairs. There are some significant secondary Pb... N and Pb... interactions which produce two different extended structures, namely a 1D chain in 1 and a 2D layer in 2. Both 1 and 2 exhibit fluorescence properties at room temperature.
2,2`-Bipyridin-1,2-dithiolat Gemischtligand-Komplexe. Synthese, Charakterisierung und EPR-Spektroskopie / 2,2`-Bipyridine-1,2-dithiolate Mixed Ligand Complexes. Synthesis, Characterisation and EPR Spectroscopy
Authors: Awad Duha Jawad , Conrad Franziska , Koch Andreas , Friedrich Alwin , Popplc Andreas , Strauch Peter
Published: February 2015

A series of new 2,2` -bipyridine/1,2-dithiolate transition metal complexes has been synthesised and characterised. As 1,2-dithiolate ligands 1,2-dithiooxalate (dto) and 1,2-dithiosquarate (dtsq) were used. It follows from the IR spectra that the multidentate dithiolate ligands coordinate exclusively via their sulfur atoms forming an MN2S2 coordination sphere. The central metal ions (M) are Cu2+, Ni2+, Pd2+, Pt2+, and Zn2+. The complex [CuII(bpy)(dto)] could be studied by EPR spectroscopy and was measured as powder, diamagnetically diluted in the isostructural [NiII(bpy)(dto)] host structure. The spin density contribution calculated from the experimental parameters is compared with the electronic situation in the frontier orbitals, namely in the semi-occupied SOMO of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT).
Catalytic Effect of Basic Alumina in the Dehydrogenation of 1,4-Dihydropyridines with Tetrabutylammonium Peroxydisulfate
Authors: Memarian Hamid R. , Barati Behjat
Published: February 2015

4-Alkyl- or 4-aryl-1,4-dihydropyridine derivatives were oxidized to the pyridine derivatives by tetrabutylammonium peroxydisulfate (n-Bu4N)2S2O8 (TBAPD) in combination with basic alumina in refluxing acetonitrile and also in the absence or presence of basic alumina under microwave irradiation. The presence of basic alumina plays an important role in the reaction mechanism. Whereas oxidation under thermal condition is assumed to occur through an ionic mechanism, ionic and also radical mechanisms are proposed for the reactions under microwave irradiation.
Two New Compounds from the Bark of Dysoxylum hainanense
Authors: Zhang Xiang-Yun , Zhang Rong-Ting , Cai Xiang-Hai , Liu Ya-Ping , Luo Xiao-Dong
Published: February 2015

Two new compounds, ent-8(9)-pimarene-20-hydroxy-16-nor-15-oic acid (1) and 20S,24-epoxy- 25,26,27-trisnor-24-oxo-3,4-seco-dammar-4(28),22-dien-3-oic acid (2), along with four known compounds have been isolated from the bark of Dysoxylum hainanense. The new structures were elucidated by spectroscopic techniques (NMR, MS, UV, IR and optical rotation). The known compound, ent-8(9)-pimarene-15,16-diol (3), was reported from D. hainanense for the first time.
Novel Alkaloids from Alstonia scholaris
Authors: Cai Xiang-Hai , Shang Jian-Hua , Feng Tao , Luo Xiao-Dong
Published: February 2015

The alkaloidal fraction of Alstonia scholaris leaves shows anti-inflammatory and analgesic bioactivity in vivo. A phytochemical study on this fraction led to the isolation of two novel alkaloids, scholarisine I and (±)-scholarisine II. Their structures were elucidated on the basis of spectroscopic methods, and a possible biogenesis is proposed. (±)-Scholarisine II selectively inhibited the inducible COX-2 rather than COX-1, and also markedly inhibited 5-LOX, comparable to positive controls.
Hydrothermal Synthesis, Crystal Structure and Properties of a 2D Network of Cd(II) Coordination Polymers with Helical Chains
Authors: Mei Chong-Zhen , Ma Ning , Li Kai-Hui
Published: February 2015

Hydrothermal reaction of Cd(II) acetate with the bridging ligand m-H4bptc (m-H4bptc = biphenyl-2,3`,3,4`-tetracarboxylic acid) yielded a new 2D metal-organic coordination polymer with helical chains in the solid state namely {[Cd2(m-bptc)(H2O)6]·(H2O)5}n (1). The helices are further connected through hydrogen bonds to give a threedimensional supramolecular network. The thermal stability of complex 1 was studied by thermogravimetric (TG) and differential thermal analysis (DTA). Compound 1 exhibits photoluminescence with an emission maximum at ca. 399 nm upon excitation at 360 nm.
The First Ammoniates of Alkali Metal Fluorides: Cesium Fluoride Ammonia (3/4) [Cs3F3(NH3)4] and Ammonium Cesium Difluoride [NH4CsF2]
Authors: Baer Sebastian A. , Kraus Florian
Published: February 2015

Two new compounds containing cesium fluoride have been obtained as side-products from the reactions of Cs2CuF6 and Cs2KDyF6 with liquid ammonia. Cs2CuF6 reacts with the solvent forming a still unknown blue substance and the colorless ammoniate Cs3F3(NH3)4 which crystallizes in the cubic space group I 4̄3d (no. 220) with a = 10.273(1) Å and V = 1084.3(2) Å3 at 123 K with Z = 4. Its crystal structure is isopointal to Y3Au3Sb4 and shows an infinite three-dimensional network made up through N-H· · ·F hydrogen bonds. Ammonium cesium difluoride NH4CsF2 crystallizes in the orthorhombic space group Pnma (no. 62) with a = 7.1791(1), b = 4.1244(1), c = 13.6417(2) Å and V = 403.92(1) Å3 at 123 K with Z = 4. The crystal structure displays two-dimensional infinite layers of the composition 2
∞[(NH4F2)−] with embedded Cs+ ions. Analogous to the structure of the compound Cs3F3(NH3)4, the structural motif is formed through strong N-H· · ·F hydrogen bonds, which seem to be the guiding force. To the best of our knowledge, the title compounds are the first reported ammoniates of alkali metal fluorides.
High-pressure Synthesis and Characterization of the Fluoride Borate Tm5(BO3)2F9
Authors: Haberer Almut , Enders Michael , Kaindl Reinhard , Huppertz Hubert
Published: February 2015

The rare earth fluoride borate Tm5(BO3)2F9 was synthesized from Tm2O3, B2O3, and TmF3 under high-pressure/high-temperature conditions of 5 GPa and 900 °C in a Walker-type multianvil apparatus. The single-crystal structure determination revealed that Tm5(BO3)2F9 is isotypic to the compounds RE5(BO3)2F9 (RE = Er,Yb). Tm5(BO3)2F9 crystallizes in the space group C2/c (Z = 4) with the parameters a = 2030.9(4), b = 606.2(2), c = 822.6(2) pm, β = 100.5(1)°, V = 995.7(3) Å3, R1 = 0.0341, and wR2 = 0.0724 (all data). The structure is composed of isolated BO3 groups, ninefold coordinated thulium cations, and fluoride anions. Infrared and Raman spectroscopic data of Tm5(BO3)2F9 are compared to the data of RE5(BO3)2F9 (RE = Er, Yb).
Photophysics of [Pt{4-(o-tolyl)isqbipy}Cl]SbF6, where 4-(o-Tolyl)isqbipy is the New 4-(o-Tolyl)-6-(3´´ -isoquinolyl)-2,2´-bipyridyl Ligand
Authors: Field John S. , Gertenbach Jan-André , Jaganyi Deogratius , McMillin David R. , Shaira Aishath , Stewart David J.
Published: February 2015

The synthesis and characterisation of the 4-(o-tolyl)-6-(3´´-isoquinolyl)-2,2´-bipyridyl [4-(otolyl) isqbipy] ligand is described. A single-crystal X-ray structure determination shows that it adopts a trans-trans conformation about the interannular bonds linking the central pyridine ring to the outer pyridine ring and the isoquinolyl moiety. The o-tolyl group is twisted by an angle of 51.7° out of the plane of the central pyridine ring. The synthesis and characterisation of the [Pt{4-(otolyl) isqbipy}Cl]SbF6 complex is described. The absorption spectrum of the complex measured in acetonitrile exhibits MLCT bands at 362 and 393 nm, as well as intraligand π-π* absorptions in the 200 - 350 nm range; the MLCT bands are shifted significantly to higher energy when compared to those recorded for the parent trpy complex, viz. [Pt{4´-(o-tolyl)trpy}Cl]SbF6, where trpy is 2,2´ : 6´,2´´-terpyridine. Similarly, the 3MLCT emission measured for the 4-(o-tolyl)isqbipy complex in a 1 : 1 CH2Cl2/CHCl3 solution is blue-shifted with respect to the emission spectrum recorded for the 4´-(o-tolyl)trpy complex. We attribute the higher energy MLCT absorption and emission for the 4-(o-tolyl)isqbipy complex to a significantly higher energy for its π*-LUMO than for that of the 4´-(o-tolyl)trpy complex. Emission spectra of the title compound have also been measured in a low-temperature 1 : 5 : 5 (v/v) DMF/methanol/ethanol (DME) glass as a function of concentration. These spectra show that aggregation of the complex occurs at rather low concentrations of 5 - 10 μM, probably to dimers. Variable-temperature emission spectra recorded on a solid sample of [Pt{4-(otolyl) isqbipy}Cl]SbF6 comprise relatively narrow asymmetric bands whose maxima are shifted to the red as the temperature is lowered: specifically λem(max) is 641 nm at r. t. (τ = 235 ns) and 676 nm at 77 K (τ = 1.36 μs). Temperature-dependent emission of this type is typical of a metal-metal-to-ligand charge transfer (MMLCT) excited state that has its origin in dz2 (Pt)-dz2 (Pt) orbital interactions in the crystal.
Synthesis, Crystal Structure, and DNA-Binding Studies of a Ni(II) Complex with the Tris(N-methylbenzimidazol-2-ylmethyl)amine Ligand
Authors: Wu Huilu , Li Ke , Sun Tao , Liu Bin , Jia Fei , Yuan Jingkun , Chen Guisheng
Published: February 2015

A tripod ligand tris(N-methylbenzimidazol-2-ylmethyl)amine (Mentb) and its nickel(II) picrate (pic) complex, with composition [Ni(Mentb)(DMF)(H2O)](pic)2, have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra, and UV/Vis measurements. Single-crystal X-ray diffraction revealed that the Ni atom is six-coordinated in a distorted octahedral geometry. In addition, the DNA-binding properties of the ligand Mentb and its Ni(II) complex have been investigated by electronic absorption, fluorescence and viscosity measurements. The experimental results suggest that the ligand and its Ni(II) complex bind to DNA via an intercalation binding mode, and their binding affinity to DNA follows the order of complex>ligand.
Synthesis of (R)-(–)-Carvone Derivatives
Authors: Sousa Damião P. de , Raphael Ellen , Brocksom Timothy J.
Published: February 2015

(R)-(-)-Carvone, the main constituent of spearmint oil, has several synthetic applications and is used in cosmetics, food, and pharmaceutical preparations. In a recent study we demonstrated that (R)-(-)-carvone shows significant analgesic activity. In the present report, (R)-(-)-carvone derivatives which have pharmacological potential are described. These compounds can be used in studies of structure-activity relationship to develop novel drugs.
RE4B4O11F2 (RE = Eu, Dy): New Phases Isotypic to the Fluoride Borate Gd4B4O11F2
Authors: Pitscheider Almut , Enders Michael , Huppertz Hubert
Published: February 2015

The rare-earth fluoride borates RE4B4O11F2 (RE = Eu, Dy) were synthesized in a Walkertype multianvil apparatus from the corresponding rare-earth oxides and fluorides, and boron oxide. Eu4B4O11F2 was obtained under high-pressure/high-temperature conditions of 5 GPa and 900 °C, and Dy4B4O11F2 at 8 GPa and 1000 °C. The single-crystal structure determinations revealed that both compounds are isotypic to Gd4B4O11F2, crystallizing in the space group C2/c (Z = 4) with the parameters a = 1368.2(3), b = 465.4(1), c = 1376.6(3) pm, β = 91.2(1)°, V = 0.8765(3) nm3, R1 = 0.0232, and wR2 = 0.0539 (all data) for Eu4B4O11F2 and a = 1349.5(3), b = 460.9(1), c = 1362.5(3) pm, β = 91.3(1)°, V = 0.8472(3) nm3, R1 = 0.0353, and wR2 = 0.0729 (all data) for Dy4B4O11F2. These phases are entirely different from the recently discovered lanthanum fluoride borate La4B4O11F2, which exhibits the same constitution in another structure type with space group P21/c.