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Single-crystal X-ray Crystallography (single-crystal + x-ray_crystallography)

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Selected Abstracts

"Tail,Tail Dimerization" of Ferrocene Amino Acid Derivatives

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2010
Daniel Siebler
Abstract Acid anhydrides of N-protected 1,-aminoferrocene-1-carboxylic acid (Fca) have been prepared and spectroscopically characterized (protection group Boc, Fmoc, Ac; 4a,4c). The structure of the Boc-derivative 4a has been determined by single-crystal X-ray crystallography. An intramolecular N,H···O hydrogen bond involving the carbamate units results in a ring structure containing the two ferrocene units, the anhydride moiety, and the hydrogen bond. In the crystal, the individual molecules are connected by intermolecular N,H···O hydrogen bonds of the carbamate unit. Experimental and theoretical studies suggest that the ring motif is also a dominant species in solution. Electronic communication across the anhydride moiety is found to be very weak as judged from electrochemical, spectroscopic, and theoretical experiments. [source]

Insertion Reactions of an Aminogermylene and Formation of a Single-Source Precursor for GeTe Thin Films

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2009
Tianniu Chen
Abstract Insertion reactions between a liquid germylene 1, and either a carbodiimide or dialkyl telluride lead to the formation of the group-14-metal(II) guanidinate complex 2 or the stable group-14-metal terminal alkyl tellurolate compound 3, respectively. The complexes 2 and 3 were structurally elucidated by multinuclear NMR and single-crystal X-ray crystallography. The use of 3 as a single-source precursor (SSP) for the MOCVD of GeTe films was demonstrated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Solid-State and Solution Structure of Lanthanide(III) Complexes with a Flexible Py-N6 Macrocyclic Ligand

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2009
Cristina Núñez
Abstract Lanthanide complexes of a hexaaza macrocyclic ligand containing a pyridine head unit (L) were synthesized (Ln = La,Lu, except Pm). The solid-state structures of the corresponding La, Ce, Pr, Nd, and Lu complexes were determined by single-crystal X-ray crystallography, and they reveal the presence of three different mononuclear complexes with three different conformations of the macrocycle and coordination environments around the metal ions. In all complexes the lanthanide ion is coordinated in an endomacrocyclic manner to the six nitrogen donor atoms of the ligand. In the La, Ce, and Pr complexes the metal ions show a 12-coordinate mononuclear environment in which 3 nitrate anions coordinate in a bidentate fashion. However, in the Nd analogue the metal ion displays a 10-coordinated environment with the coordination of 2 bidentate nitrate groups, whereas Lu shows a 9-coordinate environment interacting with 2 nitrate ligands, one of them acting as bidentate and the second one coordinating in a monodentate fashion. The 1H and 13C NMR spectra of the complexes recorded in CD3CN suggest that the complexes adopt in solution a similar structure to that observed for the Nd complex in the solid state. The [Ln(L)(NO3)3] and [Ln(L)(NO3)2]+ complexes were characterized by density functional theory (DFT) calculations (B3LYP model). The structures obtained from these calculations for La, Ce, Pr, and Nd are in good agreement with the experimental solid-state structures. The relative stabilities of the [Ln(L)(NO3)2]+ complexes with respect to the [Ln(L)(NO3)3] ones (Ln = La, Nd, Gd, Ho, or Lu) were studied both in vacuo and in acetonitrile solution (PCM model) at the same computational level. Our calculations indicate that in solution the [Ln(L)(NO3)2]+ species is the most stable one along the whole lanthanide series, in agreement with the NMR spectroscopic data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Syntheses, Characterization, and Luminescent Properties of Monoethylzinc Complexes with Anilido,Imine Ligands

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2007
Qing Su
Abstract The syntheses of three anilido,imine ligands of the general formula ortho -C6H4(NHAr,)(CH=NAr, [Ar, = 7-(2,4-Me2)C9H4N, Ar, = 2,6-Me2C6H3 (2a); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Et2C6H3 (2b); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6- iPr2C6H3 (2c)] and four zinc(II) complexes of the general formula [ortho -C6H4(NHAr,)(CH=NAr,)]ZnEt [Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Me2C6H3 (3a); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Et2C6H3 (3b); Ar, = 7-(2,4-Me2)C9H4N, Ar, = 2,6- iPr2C6H3 (3c); Ar, = 2,6-Me2C6H3, Ar, = 2,6- iPr2C6H3 (3d)] are described. The complexes were synthesized from the reaction of ZnEt2 with corresponding ligands 2 by alkane elimination. All compounds were characterized by elemental analysis and 1H and 13C NMR spectroscopy. The molecular structures of compounds 2a, 2b, 3b, and 3c were determined by single-crystal X-ray crystallography. The X-ray analysis reveals that complexes 3b and 3c exist in the dimeric form with the N atom in the quinolyl ring coordinating to the other Zn atom to make the Zn atoms four coordinate. Luminescent properties of ligands 2a,2d and complexes 3a,3d in both solution and the solid state were studied. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Di-2-pyridyl Ketone Oxime in Zinc Chemistry: Inverse 12-Metallacrown-4 Complexes and Cationic Pentanuclear Clusters

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2005
Maria Alexiou
Abstract The use of di-2-pyridyl ketone oxime (Hpko)/X, "blends" (X, = PhCO2,, N3,, NCO,, acac,, NCS,) in zinc chemistry yields neutral tetranuclear and cationic pentanuclear clusters. Various synthetic procedures have led to the synthesis of compounds [Zn4(OH)2(O2CPh)2(pko)4]·3MeCN (1·3MeCN), [Zn4(OH)2(N3)2(pko)4]·4DMF (2·4DMF), [Zn4(OH)2(NCO)2(pko)4]·3DMF·H2O (3·3DMF·H2O), [Zn4(OH)2(acac)2(pko)4]·4CH2Cl2 (4·4CH2Cl2), [Zn5Cl2(pko)6][ZnCl(NCS)3]·2.5H2O·1.5MeOH (5·2.5H2O·1.5MeOH) and [Zn5(NCS)2(pko)6(MeOH)][Zn(NCS)4]·2.5H2O·MeOH (6·2.5H2O·MeOH). The structures of the six complexes have been determined by single-crystal X-ray crystallography. The tetranuclear molecules of 1,4 lie on a crystallographic inversion centre and have an inverse 12-metallacrown-4 topology. Two triply bridging hydroxides are accommodated in the centre of the metallacrown ring. The pko, ligands form a propeller configuration that imposes absolute stereoisomerism with , and , chirality. Two metal ions are in distorted O2N4 octahedral environments, whereas the rest are in severely distorted tetrahedral or trigonal bipyramidal environments. The five Zn ions of the cations of 5 and 6 are held together by six pko, ligands which adopt three different coordination modes; the chloro (5) and isothiocyanato (6) ligands are terminal. The five Zn ions define two nearly equilateral triangles sharing a common apex, and the novel Zn5 topology can be described as two "collapsed" 9-metallacrown-3 structures sharing a common Zn apex. Besides the pentanuclear cations, the structures of 5 and 6 contain slightly distorted tetrahedral [ZnCl(NCS)3]2, and [Zn(NCS)4]2, ions, respectively, with the isothiocyanato ligands binding the metal ion in a virtually linear fashion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Preparation of Diamidochloro(cyclopentadienyl)titanium Derivatives as Pre-Catalysts for Olefin Polymerization , X-ray Molecular Structure of [Ti(,5 -C5H5){1,2-C6H4(NCH2CH2CH3)2}Cl] and [Ti{,5 -C5H4(SiMe3)}{1,2-C6H4(NCH2CH2CH3)2}Cl]

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2004
Vanessa Tabernero
Abstract The synthesis of N,N,-alkyl 1,2-phenylenediamines 1,2-C6H4(NHR)2 [R = CH2CH2CH3 (nPr), CH2tBu (Np)] was carried out in three steps by lithiation of the primary 1,2-phenylenediamine, reaction with the appropriate acyl chloride and reduction with LiAlH4. The addition of nBuLi to a stirred solution of N,N,-alkyl diamines in cold hexane resulted in the immediate deposition of the corresponding lithium salts, which react with [MCpR,Cl3] to give the diamidochloro(,5 -cyclopentadienyl)titanium and -zirconium complexes [MCpR,{1,2-C6H4(NR)2}Cl] (4,10) [M = Ti, Zr; CpR, = ,5 -C5H5, ,5 -C5(CH3)5, ,5 -C5H4(SiMe3); R = nPr, Np]. The compound [Ti(,5 -C5H5){1,2-C6H4(NnPr)2}Cl] (3) was obtained by treatment of [Ti(,5 -C5H5)Cl3] with 1,2-C6H4(NHnPr)2 in the presence of NEt3 in toluene. All the reported compounds were characterized by the usual analytical and NMR spectroscopic methods. The molecular structures of 3 and 7 were determined by single-crystal X-ray crystallography. The compounds described here were further investigated as potential olefin polymerization catalysts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

On the Photochemical Stability of the 9-Mesityl-10-methylacridinium Cation

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2009
Andrew C. Benniston
Abstract The 9-mesityl-10-methylacridinium cation in aerated deuterated/normal acetonitrile decomposes to give several side products when continuously exposed to white light. The main breakdown product isolated by column chromatography is identified as 3,5-dimethyl-4-(10-methylacridinium)benzaldehyde. This assignment was confirmed by single-crystal X-ray crystallography. In light of these findings it appears that decomposition pathways also need to be considered when discussing the photochemical properties of the 9-mesityl-10-methylacridinium cation, especially in the presence of dioxygen.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Synthesis and Stereochemical Aspects of 2,6-Disubstituted Perhydroazulenes , Core Units for a New Class of Liquid Crystalline Materials

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2006
Zakir Hussain
Abstract A novel approach for the synthesis of cis/trans -fused perhydroazulenes 13,19 is reported. The stereochemistry of the derivatives of carbene addition products 9a,c/20,22, of the 2,6-disubstituted perhydroazulenes 12a,c/23,25, and that of compounds 26,27 has been studied by single-crystal X-ray crystallography. The hydrogenation of the tropylidene to the perhydroazulene skeleton under various conditions is described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

6-Di­methoxy­methyl-1-methoxy­carbonyl­bi­cyclo­[3.1.0]­hex-2-ene-2-carboxyl­ic acid

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2000
Satomi Niwayama
The title compound, C12H16O6, prepared by a standard synthetic method, was determined by single-crystal X-ray crystallography to exist with a cyclo­propane ring fused to a cyclo­pentene ring. Comparison of the unit-cell dimensions and space group of this material with those of a crystal of the same material prepared using a route involving pig liver esterase hydro­lysis shows them to be identical. [source]

Curvularides,A,E: Antifungal Hybrid Peptide,Polyketides from the Endophytic Fungus Curvularia geniculata

CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010
Dr. Porntep Chomcheon
Abstract Five new hybrid peptide,polyketides, curvularides,A,E (1,5), were isolated from the endophytic fungus Curvularia geniculata, which was obtained from the limbs of Catunaregam tomentosa. Structure elucidation for curvularides,A,E (1,5) was accomplished by analysis of spectroscopic data, as well as by single-crystal X-ray crystallography. Curvularide,B (2) exhibited antifungal activity against Candida albicans, and it also showed synergistic activity with a fluconazole drug. [source]

Utilization of Self-Sorting Processes To Generate Dynamic Combinatorial Libraries with New Network Topologies

CHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2006
Isabelle Saur Dr.
Abstract The synthesis of water-soluble, organometallic macrocycles is described. They were obtained by self-assembly in reactions of the half-sandwich complexes [{Ru(C6H5Me)Cl2}2], [{Ru(p -cymene)Cl2}2], [{Rh(Cp)Cl2}2], and [{Ir(Cp*)Cl2}2] with the ligand 5-dimethylaminomethyl-3-hydroxy-2-methyl-4-(1H)-pyridone in buffered aqueous solution at pH 8. The structure of the Ru,(p -cymene) complex was determined by single-crystal X-ray crystallography. Upon mixing, these complexes undergo scrambling reactions to give dynamic combinatorial libraries. In combination with structurally related complexes based on amino-methylated 3-hydroxy-2-(1H)-pyridone ligands, an exchange of metal fragments but no mixing of ligands was observed. This self-sorting behavior was used to construct dynamic combinatorial libraries of macrocycles, in which two four-component sub-libraries are connected by two common building blocks. This type of network topology influences the adaptive behavior of the library as demonstrated in selection experiments with lithium ions as the target. [source]

Two New Pregnanone Derivatives with Strong Cytotoxic Activity from Pachysandra axillaris

CHEMISTRY & BIODIVERSITY, Issue 7 2005
Ming-Hua Qiu
Two new, bioactive, pregnane-based natural products, pachysanonin (=3,,11,,12,)-12-acetoxy-3-(dimethylamino)-11-[(3,4-dimethylpent-3-enoyl)oxy]pregnan-20-one; 1) and pachysanone (=(11,,12,)-12-acetoxy-11-[(3,4-dimethylpent-3-enoyl)oxy]pregnan-3,20-dion; 2) have been isolated from Pachysandra axillaris. Their structures were determined by spectroscopic methods, and, in the case of 2, by single-crystal X-ray crystallography (Figure). Compound 2 showed significant antitumor activity against Lewis lung carcinoma (LCC) tumor cells, with an IC50 value of 0.020±0.006,,g/ml, which is equal or even lower than those of the well-known natural antitumor agents harringtonine (0.02), homoharringtonine (0.15), and adriamycin (0.06,,g/ml; positive control). [source]