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Synthesis and crystal structure determination of the bicyclic [bis(μ -P,N-1-benzyl-2-imidazolyl-diphenylphosphine)(μ -O,O'-diperchlorate)dimercury(II)][diperchlorate].
No full textIn the attempt to test the oxidizing capability of group 12 perchlorate salts in the regards of phosphane ligands, the 1:1 molar ratio reactions between a donor P, N phosphane ligand (1-benzyl-2-imidazolyl-diphenylphosphine, L) and the respective salts have been performed. In all the cases no ligand oxidation was observed while the metal complexation was highlighted. The species L2M2(ClO4)4 was formed with an increasing predominance from Cd<Zn<Hg. The complex L3M(ClO4)2 was the only solid product isolated in the case of cadmium and the predominant species in solution both for zinc and cadmium reactions. The crystal structure of [bis(μ-P,N-1-benzyl-2-imidazolyl-diphenylphosphine)(μ-O,O’-diperchlorate)dimercury(II)][diperchlorate] shows two centrosymmetric Hg atoms as a part of an eight member cycle formed by two bridging (Bzim)Ph2P ligands coordinated in a head-to-tail mode with P and N as donor atoms. Each Hg atom interacts with the oxygen atoms of two symmetry related molecules of ClO4- that bridge the metal centres forming a second eight member cycle, roughly normal to the first one
Au center dot center dot center dot H-C Interactions in Gold(I) Complexes with Benzyl Imidazolyl Phosphine Ligands
No full textSecondary interactions in gold(I) compounds have assumed
considerable interest, since they have a profound influence on
chemical and physics properties, structures and conformations
of gold complexes. In the last years a large number of secondary
bonding interactions has been discovered in compounds of
gold(I), mostly of the general type L-Au-X, where L is a
phosphine ligand and X is a halide or a pseudohalide. Distinct
kinds of interaction involving gold atoms are: Au•••Au
(aurophilic interaction), Au•••X where X is a halide,
Au••• -system, Au•••H-C. This last type of contact is very rare
either as hydrogen bond or as agostic interaction. The tertiary
phosphines (BzIm)Ph2P, 1-benzyl-2-imidazolyl diphenyl
phosphine, and (BzIm)3P, tris-(1-benzyl-2-imidazolyl)phosphine,
have features to systematically allow Au•••H-C contacts, also
coexisting with aurophilic interactions. In fact, they are able to
bring the hydrogen atoms of the benzyl groups in close position
to the gold atom by a change of conformation. In the complex
[(BzIm)Ph2PAuCl] [1], where only one benzyl imidazolyl
group is present, the assumed conformation is favourable for the
CH2 group to have one hydrogen atom at close distance from Au
(2.62 Å). In the complex, [(BzIm)3PAuCl], two benzyl
imidazolyl groups position one hydrogen atom of each CH2
group at close distances from gold (2.83 and 2.95 Å). In the
tetranuclear gold cluster [{(BzIm)3P}2Au4Cl2]2+ with the two
(BzIm)3P phosphines, which act as bihapto ligands, two gold
atoms each interact with one hydrogen atom at distances of 2.57
and 2.59 Å.
[1] Burini, A.; Pietroni, B. R.; Galassi, R; Valle, G.; Calogero, S.
Inorg. Chim. Acta 1995, 229, 299-305
Crystal structure of a novel Hg(II) complex, [Hg(tri-2-furylphosphine)2(tri-2-furylphosphinoxide)3][ClO4]2
No full textThe Hg(II) complex [Hg(TFP)2(OTFP)3][ClO4]2 with TFP = tri-2-furyl-phosphine and OTFP = tri-2-furylphosphinoxide has been prepared and characterized. It crystallizes in the hexagonal P63/m space group with Z=2, a=13.308(3), c=21.092 (4) Å , V=3235(1) Å3. The structure of the complex cation consists of independent molecules with Hg pentacoordinated in exact trigonal bipyramidal geometry
"Direct resolution of optically active isomers on chiral packings containing ergoline skeleton. 6. Enantioseparation of profens
No full textThe enantioselective behaviour of some underivatized 2-arylpropionic acids (profens) and flobufen by HPLC using a terguride-based chiral stationary phase was tested. X-ray analysis of crystals of the chiral selector and its complexes with naproxen allowed a deeper insight into the enantiodiscriminative process. The column stability and reproducibility, and the potential of the packing for semipreparative scale separations were also determined. A method for determining flobufen enantiomers and metabolites in plasma samples is described
Enantioseparation of 2-aryloxypropionic acids on chiral porous monolithic columns by capillary electrochromatography - Evaluation of column performance and enantioselectivity
No full textThe enantioseparation of 2-aryloxypropionic acids by capillary electrochromatography was tested on columns with a monolithic stationary phase prepared from silanized fused-silica capillaries (100 microm I.D.) by in situ copolymerization of glycidyl methacrylate, ethylene glycol dimethacrylate and methyl methacrylate in the presence of formamide and 1-propanol as the porogen solvents. The porous chiral monolithic stationary phases were prepared by reaction of the epoxy-groups at the surface of the monolith with (+)-1-(4-aminobutyl)-(5R,8S,10R)-terguride. To attain the minimum HETP values for the enantiodiscrimination of 2-phenoxypropionic acid, the influence of the composition of polymerization solution on column total porosity and efficiency was investigated. Optimum mobile phase conditions were found for all analytes tested using acetonitrile-methanol mixtures containing triethylamine and acetic acid as the buffer components. Furthermore, the chemical and mechanical stabilities of the columns were satisfactory, allowing hundreds of analyse
Solid state solution structural studies of silver(I) cyclic complex bearing the (Bzim)Ph2P ligand
No full textThe synthesis and crystal stucture detrmination of silver(I)cyclic complex bearing the (Bzim)Ph2P ligand is described
Reactivity of bis(diphenylphosphines)digold(I) dications with azotate neutral heterocycles: X-ray crystal strucutre of eclipsed [m-dppmAu2(pzH)]2+ 2ClO4- and staggered [m-dppeAu2(pzH)2]2+ 2ClO4- complexes.
No full textSynthesis and X-ray crystal structure determination of dinuclear gold(I) complexes stabilized by phosphine and azolate ligand
Solid state and solution structural studies of silver(I) cyclic complexes bearing the (Bzim)Ph2P ligand
No full textCyclic silver(I) compounds having a [mu-(Bzim)Ph2PAg](2)(2+) unit ((Bzim)Ph2P 1-benzyl-2-imidazolyldiphenylphosphine) and NO3- (I), BF4- (II), and B[3,5-(CF3)(2)C6H3](4)(-) (III) as counterions were characterized in the solid state by X-ray crystal structure determinations (I, II), and in solution by H-1-, C-13-, F-19- and P-31-NMR spectroscopies. The crystal structure of complex [mu-(Bzim)Ph2PAg(NO3)](n) (n = 2, 4) (I) (triclinic, space group (no. 2), a = 15.118(5), b = 17.755(3), c = 14.123(4) Angstrom, alpha = 90.23(2), beta = 111.67(2), gamma = 85.92(2)degrees, Z = 2) shows two conformers A and B in the unit cell. The conformer A consists of a tetranuclear species formed by two [mu-(Bzim)Ph2PAg](2)(2+) moieties, related by a center of symmetry, bonded together by two bridging nitrate anions. The nitrate anions are coordinated to the sliver atoms in an unusual fashion. The conformer B is a dinuclear species where the silver atoms present in the eight-membered ring complete their tetracoordination with two chelate nitrate anions. The crystal structure of complex {[mu-(Bzim)Ph2PAg(BF4)](2)}(infinity) (II) (monoclinic, space group P2(1)/c (no. 14), a = 11.563(3), b = 8.353(4), c = 26.188(7) Angstrom, beta = 95.88(2)degrees, Z = 2) consists of infinite chains of the dinuclear cyclic silver moieties held together by BF4- bridging anions. The low temperature experimental and simulated P-31-NMR spectra of complexes I-III show complex apparent doublets of multiplets due to the resonance of the spin systems of the three isotopomers of the silver atoms present in the cyclic units. The interionic solution structure of complex II was investigated by F-19{H-1}-HOESY NMR spectroscopy. In methylene chloride solution the BF4- anion is not more coordinated to the silver(I) atoms as in the solid state, and it is localized in between the phenyl and benzyl groups of the ligand. (C) 2000 Elsevier Science S.A. All rights reserved
Crystal structure of bis(3,5-dimethylpyrazole)-N,N'-m -[1,3-bis(diphenylphosphino)propane]-P,P'-digold(I)] diperchlorate, C37H42N4P2Au2Cl2O8
No full textThe dinuclear gold(I) dicationic complex [m-dpppAu2(pzH)2]2+. 2ClO4-
prepared reacting [m-dpppAu2]2+. 2ClO4- (dppp = 1,3-bis(diphenylphosphi
propane) with the azotate neutral heterocycle 3,5-dimethylpyrazole (pzH), as
ancillary ligand, in THF. The X-ray crystal structure is reported: monoclinic,
space group C 2/c, a=22.598(3), b=11.626(1), c=18.539(2)\A, \b=116.37(1)\,
V=4364(1)\A3, z=4. The structure consists in centrosymmetric dinuclear units,
where the gold atoms show approximately linear coordination with P-Au-N of
177.97(2)\. The gold(I) centres assume an anti conformation with a torsion
angle Au-P-P-Au of 89.2(2)\. No intra or inter-molecular gold-gold interactions
occurr. The perclorate anions are bonded by hydrogen bonds to N-H of the
pyrazole rings
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