Three-coordinate iron complexes: x-ray structural characterization of the iron amide-bridged dimers [Fe(NR2)2]2 (R = SiMe3, C6H5) and the adduct Fe[N(SiMe3)2]2(THF) and determination of the association energy of the monomer Fe{N(SiMe3)2}2 in solution

1991 ◽  
Vol 30 (11) ◽  
pp. 2547-2551 ◽  
Author(s):  
Marilyn M. Olmstead ◽  
Philip P. Power ◽  
Steven C. Shoner
1994 ◽  
Vol 47 (2) ◽  
pp. 405 ◽  
Author(s):  
PK Bharadwaj ◽  
AM Lee ◽  
BW Skelton ◽  
BR Srinivasan ◽  
AH White

Single-crystal room-temperature X-ray structure determinations of the title compounds have been carried out. The two compounds are isomorphous, and isomorphous with the previously determined iodide analogue, being monoclinic, P 21/c, a ≈ 10.0, b ≈ 14.9, c ≈ 7.8 Ǻ, β ≈ 92°, Z = 4 formula units; residuals were 0.037, 0.036 for 2197, 1654 'observed' reflections for X = Cl , Br respectively. As in the iodide, the complexes are infinite polymers, with successive bismuth atoms bridged by the two halides and one sulfur atom of the ligand , which also chelates each bismuth. The structure determination of C5H5NCONEt2]2 [Cl5Bi(NC5H5)], isostructural with its thiocarbamoyl analogue, is also recorded.


1989 ◽  
Vol 42 (2) ◽  
pp. 335 ◽  
Author(s):  
LM Engelhardt ◽  
JM Patrick ◽  
AH White

The isolation and single-crystal X-ray structure determination of the title compound, [(phen)2Pb(NCS)(O2NO)] is described; crystals are triclinic, P1, a 15.554(7), b 9-670(4), c 8.429(3) α 72.53(3), β 81.90(3), γ 72.88(3)� Z = 2, yielding R 0.052 for 3405 independent 'observed' reflections. The lead atom is seven-coordinate [Pb-N 2.49(1)-2.60(1) (phen), 2.89(1) (NCS); Pb-O 2.75(1), 2.89(1) �] with a large vacancy in the coordination sphere, possibly indicative of a stereochemically active lone pair.


2017 ◽  
Vol 13 ◽  
pp. 1145-1167 ◽  
Author(s):  
Serge Pérez ◽  
Daniele de Sanctis

Synchrotron radiation is the most versatile way to explore biological materials in different states: monocrystalline, polycrystalline, solution, colloids and multiscale architectures. Steady improvements in instrumentation have made synchrotrons the most flexible intense X-ray source. The wide range of applications of synchrotron radiation is commensurate with the structural diversity and complexity of the molecules and macromolecules that form the collection of substrates investigated by glycoscience. The present review illustrates how synchrotron-based experiments have contributed to our understanding in the field of structural glycobiology. Structural characterization of protein–carbohydrate interactions of the families of most glycan-interacting proteins (including glycosyl transferases and hydrolases, lectins, antibodies and GAG-binding proteins) are presented. Examples concerned with glycolipids and colloids are also covered as well as some dealing with the structures and multiscale architectures of polysaccharides. Insights into the kinetics of catalytic events observed in the crystalline state are also presented as well as some aspects of structure determination of protein in solution.


CrystEngComm ◽  
2014 ◽  
Vol 16 (36) ◽  
pp. 8555-8562 ◽  
Author(s):  
Amanda Laura Ibiapino ◽  
Rafael Cardoso Seiceira ◽  
Altivo Pitaluga ◽  
Antonio Carlos Trindade ◽  
Fabio Furlan Ferreira

Crystal structure determination of form I of anhydrous rifampicin by X-ray powder diffraction data. Crystal morphology prediction revealed a good agreement with the images of the crystals.


1999 ◽  
Vol 52 (6) ◽  
pp. 481 ◽  
Author(s):  
Cameron J. Kepert ◽  
Lioubov I. Semenova ◽  
Lu Wei-Min ◽  
Brian W. Skelton ◽  
Allan H. White

A room-temperature single-crystal X-ray structure determination of the 1 : 1 adduct of 1,10-phenanthroline (`phen") with lutetium(III) acetate (as its dihydrate) is recorded. Crystals are triclinic, P 1, a 12·430(8), b 10·681(4), c 8·134(8) Å, α 74·76(6), β 84·81(7), γ 74·29(4)°, Z = 2 f.u.; conventional R on |F| was 0·031 for No 3939 independent ‘observed’ (I > 3σ(I)) diffractometer reflections. The complex [(N,N′-phen)(O,O′-ac)Lu(O-ac-O′)4Lu(O,O′-ac)(N,N′-phen)].2H2O is binuclear, the lutetium being eight-coordinated by bidentate phen and ac (acetate) ligands and four oxygen atoms from the bridging acetate ligands. Also recorded is the structural characterization of 1 : 1 Lu(ac)2Cl/tpy (tpy = 2,2′:6′,2″-terpyridine) as its pentahydrate; this complex is triclinic, P 1, a 12·410(3), b 11·559(4), c 9·976(4) Å, α 85·19(3), β 70·30(3), γ 65·70(2)°, Z = 2, R 0·049 for No 4717. The complex is shown to be [(tpy)(H2O)2Lu(O2CCH3)2]Cl.3H2O, with the lutetium nine-coordinated by tridentate tpy, a pair of bidentate acetates and two unidentate water molecules, with the chloride uncoordinated. Structural characterizations of a number of 1 : 1 adducts of variously solvated lanthanoid(III) trichloroacetates, Ln(tca)3, with tpy are also recorded. Yb(tca)3/tpy/MeOH (1 : 1 : 1) is triclinic, P 1, a 14·016(4), b 12·951(5), c 9·604(3) Å, α 73·89(3), β 76·56(3), γ 69·20(3)°, Z = 2 f.u., R 0·057 for No 4465. The complex is mononuclear, the eight-coordinate N3YbO5 array containing tridentate tpy, unidentate methanol, and two unidentate and one bidentate chelating anions. 1 : 1 : 1 Ln(tca)3/tpy/OH2 adducts for Ln = La(-)Nd are triclinic, P 1, a ≈ 13·4, b ≈ 12·47, c ≈ 11·5 Å, α ≈ 114·5, β ≈ 89·9, γ ≈ 115·6°, Z = 1 binuclear array, R 0·061, 0·071 for No 3240, 2394. The two Ln atoms are O,O′-bridged by a pair of anions, the N3LnO6 nine-coordinate lanthanoid environment being completed by a tridentate tpy, one water, one unidentate and one bidentate anion. A 1 : 1 : 1 Lu(tca)3/tpy/OH2 array, by contrast, is triclinic, P 1, a 16·569(8), b 14·815(5), c 14·375(6) Å, α 62·05(3), β 81·35(4), γ 77·97(3)°, Z = 4 ‘mononuclear’ f.u., R 0·067 for No 6710. The array, remarkably, contains species of both of the above types in a 1 : 2 binuclear-to-mononuclear ratio, but with water replacing methanol in the mononuclear array.


2005 ◽  
Vol 60 (7) ◽  
pp. 741-744 ◽  
Author(s):  
M. R. Fadaei ◽  
A. Morsali ◽  
Ali R. Mahjoub

Determination of the structure of the [Tl2(phthalate)] by X-ray crystallography shows that there are six (TlO6) and five (TlO5) coordinate Tl atoms. The complex is a two-dimensional coordination polymer.


2018 ◽  
Vol 74 (12) ◽  
pp. 1795-1799
Author(s):  
Volker Lorenz ◽  
Phil Liebing ◽  
Liane Hilfert ◽  
Sabine Busse ◽  
Frank T. Edelmann

The first potassium amidinoguanidinate complex, catena-poly[[bis(μ-1-amidinato-N,N′,N′′,N′′′-tetraisopropylguanidinato-κ5 N 1:N 1,N 2:N 2,N 4)dipotassium]-μ-1,2-dimethoxyethane-κ2 O:O′], [K2(C14H32N4)2(C4H10O2)] n or [{ i PrN= CHN( i Pr)N(N i Pr)2K}2(μ-DME)] n where DME is 1,2-dimethoxyethane, has been synthesized and structurally characterized. The title compound was isolated in 76% yield from a reaction of N,N′-diisopropylcarbodiimide with potassium hydride in DME. The single-crystal X-ray structure determination of the title compound revealed a polymeric chain structure comprising cage-like dimeric units, with the amidinoguanidinate ligand displaying a mixed σ-/π-coordination mode.


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