Search results for "kiderakenne"
showing 10 items of 15 documents
N2,N2.N6,N6-Tetrakis(perfluorobenzoyl)-2,6-diaminopyridine
2011
The title compound, C³³H³F²⁰N³O⁴, is a highly fluorinated organic imide that was isolated as an unexpected product from the reaction of 2,6-diaminopyridine with 2,3,4,5,6-pentafluorobenzoyl chloride in a 1:2 molar ratio. The molecule is located on a twofold axis and one of its symmetry-independent 2,3,4,5,6-pentafluorobenzoyl groups is disordered over two sets of sites, the occupancy of the major component being 0.773 (3). In the major component, the dihedral angle between the perfluorophenyl groups is 63.64 (10)°, and these groups form dihedral angles of 67.14 (7) and 21.1 (2)° with the pyridine core. Short intermolecular C-HO and C-H...N contacts are found in the crystal structure. peerRe…
A linear Fe-O-Fe unit in bis(dibenzyldimethylammonium)-oxo-di[tribromoferrate(III)]
2006
The title compound, (C16H20N)2[Fe2Br6O], crystallizes with one dibenzyldimethylammonium cation and one half of a [mu]-oxo-bis[tribromoferrate(III)] anion in the asymmetric unit. The bridging oxo group is situated on an inversion centre, resulting in a linear conformation for the Fe-O-Fe unit. The iron(III) cations have tetrahedral geometry, with bond angles in the range 106.8 (1)-112.2 (1)°. The ion pairs are held together by Coulombic forces and C-H...Br hydrogen bonds. Each Br- anion forms one hydrogen bond. No C-H...O hydrogen bonds are found between the O atom in the Fe-O-Fe unit and surrounding counter-cations, consistent with the linear configuration of the Fe-O-Fe unit. peerRevie…
Structure and characterization of a novel chicken biotin-binding protein A (BBP-A)
2007
Background. The chicken genome contains a BBP-A gene showing similar characteristics to avidin family genes. In a previous study we reported that the BBP-A gene may encode a biotin-binding protein due to the high sequence similarity with chicken avidin, especially at regions encoding residues known to be located at the ligand-binding site of avidin. Results. Here, we expand the repertoire of known macromolecular biotin binders by reporting a novel biotin-binding protein A (BBP-A) from chicken. The BBP-A recombinant protein was expressed using two different expression systems and purified with affinity chromatography, biochemically characterized and two X-ray structures were solved – in comp…
A Simple Complex on the Verge of Breakdown: Isolation of the Elusive Cyanoformate Ion
2014
Cyanide Hitches a Ride Cyanide is a by-product of the biosynthesis of ethylene in plants and it has been somewhat puzzling how the ion is safely removed before it can shut down enzymatic pathways by coordination to catalytic iron centers. A proposed mechanism has implicated the cyanoformate ion—essentially, a weak adduct of cyanide and carbon dioxide—as the initial product, although its lifetime was uncertain. Murphy et al. (p. 75 ; see the Perspective by Alabugin and Mohamed ) crystallized this previously elusive adduct and found that its solution-phase stability varies inversely with the dielectric properties of the medium. The results bolster a picture in which the adduct shuttles the cy…
cis,cis,cis-(Acetato-k2O,O´)bis[1,2-bis- (diphenylphosphanyl)ethane-k2P,P´]- ruthenium(II) 0.75-trifluoromethanesulfonate 0.25-chloride
2013
In the title RuII carboxylate compound, [Ru(C₂H₃O₂)(C₂₆H₂₄P₂)₂](CF₃O₃S)₀.₇₅Cl₀.₂₅, the distorted tris-bidentate octahedral stereochemistry about the RuII atom in the complex cation comprises four P-atom donors from two 1,2-bis(diphenylphosphanyl)ethane ligands [Ru-P = 2.2881 (13)-2.3791 (13) Å] and two O-atom donors from the acetate ligand [Ru-O = 2.191 (3) and 2.202 (3) Å]. The disordered counter-anions are located on the same site in the structure in a 3:1 ratio, the expanded formula comprising four complex cations, three trifluoromethanesulfonate anions and one chloride anion, with two such formula units in the unit cell. peerReviewed
Direct observation of a borane–silane complex involved in frustrated Lewis-pair-mediated hydrosilylations
2014
Perfluorarylborane Lewis acids catalyse the addition of silicon–hydrogen bonds across C=C, C=N and C=O double bonds. This ‘metal-free’ hydrosilylation has been proposed to occur via borane activation of the silane Si–H bond, rather than through classical Lewis acid/base adducts with the substrate. However, the key borane/silane adduct had not been observed experimentally. Here it is shown that the strongly Lewis acidic, antiaromatic 1,2,3-tris(pentafluorophenyl)-4,5,6,7-tetrafluoro-1-boraindene forms an observable, isolable adduct with triethylsilane. The equilibrium for adduct formation was studied quantitatively through variable-temperature NMR spectroscopic investigations. The interacti…
Two (E)-2-({[4-(dialkylamino)phenyl]- imino}methyl)-4-nitrophenols
2012
The slow evaporation of analytical NMR samples resulted in the formation of crystals of (E)-2-({[4-(dimethylamino)phenyl]imino}methyl)-4-nitrophenol, C15H15N3O3, (I), and (E)-2-({[4-(diethylamino)phenyl]imino}methyl)-4-nitrophenol, C17H19N3O3, (II). Despite the small structural difference between these two N-salicylideneaniline derivatives, they show different space groups and diverse molecular packing. The molecules of both compounds are close to being planar due to an intramolecular O-H...N hydrogen bond. The 4-alkylamino-substituted benzene ring is inclined at an angle of 13.44 (19)° in (I) and 2.57 (8)° in (II) with respect to the 4-nitro-substituted phenol ring. Only very…
Preparation of potentially porous, chiral organometallic materials through spontaneous resolution of pincer palladium conformers.
2013
Understanding the mechanism by which advanced materials assemble is essential for the design of new materials with desired properties. Here, we report a method to form chiral, potentially porous materials through spontaneous resolution of conformers of a PCP pincer palladium complex ({2,6-bis[(di-t-butylphosphino)methyl]phenyl}palladium(II)halide). The crystallisation is controlled by weak hydrogen bonding giving rise to chiral qtz-nets and channel structures, as shown by 16 such crystal structures for X = Cl and Br with various solvents like pentane and bromobutane. The fourth ligand (in addition to the pincer ligand) on palladium plays a crucial role; the chloride and the bromide primaril…
N-[2-(2,2-Dimethylpropanamido)- pyrimidin-4-yl]-2,2-dimethyl- propanamide n-hexane 0.25-solvate hemihydrate
2013
The asymmetric unit of the title compound, C₁₄H₂₂N₄O₂·0.25C₆H₁₄·0.5H₂O, contains two independent molecules of 2,4-bis(pivaloylamino)pyrimidine (M) with similar conformations, one water molecule and one-half n-hexane solvent molecule situated on an inversion center. In one independent M molecule, one of the two tert-butyl groups is rotationally disordered between two orientations in a 3:2 ratio. The n-hexane solvent molecule is disordered between two conformations in the same ratio. The water molecule bridges two independent M molecules via O-H...O, N-H...O and O-H...N hydrogen bonds into a 2M·H₂O unit, and these units are further linked by N-H...N hydrogen bonds into chains running in the […
3,4,5-Trimethoxy-4'-methylbiphenyl
2013
In the title compound, C16H18O3, the dihedral angle between the benzene rings is 33.4 (2)°. In the crystal, molecules are packed in a zigzag arrangement along the b-axis and are interconnected via weak C—H⋯O hydrogen bonds, and C—H⋯π interactions involving the methoxy groups and the benzene rings of neighbouring molecules.