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Search Results: 1 - 10 of 193820 matches for " Da-Cheng Li "
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Bis[aqua(2,3-naphtho-15-crown-5)sodium] tetrakis(thiocyanato-κN)cobaltate(II)
Chengjuan Li,Da-Cheng Li,Da-Qi Wang
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809038641
Abstract: The title complex, [Na(C18H22O5)(H2O)]2[Co(NCS)4], consists of two aqua(2,3-naphtho-15-crown-5)sodium complex cations and one [Co(NCS)4]2 complex anion, which has crystallographic overline 1 symmetry. In the anion, the CoII centre is coordinated by the N atoms of four NCS ligands in a distorted tetrahedral geometry. In the complex cations, the NaI centre is coordinated by five O atoms of the 2,3-naphtho-15-crown-5 ligand and one water O atom. The complex molecules form a two-dimensional network via weak O—H...S interactions between adjacent cations and anions
catena-Poly[[[bis(thiourea-κS)copper(I)]-μ-thiourea-κ2S:S] iodide acetonitrile hemisolvate]
Li Jia,Ling-Qian Kong,Da-Cheng Li
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808007265
Abstract: The title complex, {[Cu(CH4N2S)3]I·0.5CH3CN}n, was formed by the reaction of CuI and thiourea in acetonitrile. There are two independent CuI ions in the asymmetric unit which are coordinated by two terminal and two bridging thiourea ligands to form a one-dimensional helical chain structure progagating in the a-axis direction. Each CuI ion is in a distorted tetrahedral coordination environment. The crystal structure is stabilized by weak N—H...S and N—H...I hydrogen bonds.
cis-Bis(2,2′-bipyridyl)dicyanatocobalt(II)
LI Jia,Ling-Qian Kong,Da-Cheng Li
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808007617
Abstract: In the title complex, [Co(NCO)2(C10H8N2)2], the Co atom is coordinated by four N atoms from two 2,2′-bipyridyl ligands and two N atoms from two cyanate anions in a distorted octahedral geometry. The Co atom lies on a twofold rotation axis. The average Co—N bond length is 2.126 (7) . Weak intermolecular C—H...O interactions lead to the formation of a three-dimensional network.
Bis[2-hydroxy-N′-(2-hydroxybenzoyl)benzohydrazitato]dipyridinecadmium(II)
Yu-Ting Chen,Da-Cheng Li
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808034533
Abstract: The title complex, [Cd(C14H11N2O4)2(C5H5N)2], exhibits crystallographic twofold symmetry. The CdII atom is located on the twofold rotation axis and reveals a slightly distorted octahedral coordination defined by four atoms (N2O2) from two symmetry-related chelate ligands and two pyridine N atoms. Intramolecular O—H...O and N—H...O hydrogen bonds stabilize the molecular conformation while intermolecular O—H...O hydrogen bonding links molecules into a triad, generating a helix along the threefold screw axis.
Structural Basis for Distinct Binding Properties of the Human Galectins to Thomsen-Friedenreich Antigen
Cheng-Feng Bian, Ying Zhang, Hui Sun, De-Feng Li, Da-Cheng Wang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025007
Abstract: The Thomsen-Friedenreich (TF or T) antigen, Galβ1-3GalNAcα1-O-Ser/Thr, is the core 1 structure of O-linked mucin type glycans appearing in tumor-associated glycosylation. The TF antigen occurs in about 90% of human cancer cells and is a potential ligand for the human endogenous galectins. It has been reported that human galectin-1 (Gal-1) and galectin-3 (Gal-3) can perform their cancer-related functions via specifically recognizing TF antigen. However, the detailed binding properties have not been clarified and structurally characterized. In this work, first we identified the distinct TF-binding abilities of Gal-1 and Gal-3. The affinity to TF antigen for Gal-3 is two orders of magnitude higher than that for Gal-1. The structures of Gal-3 carbohydrate recognition domain (CRD) complexed with TF antigen and derivatives, TFN and GM1, were then determined. These structures show a unique Glu-water-Arg-water motif-based mode as previously observed in the mushroom galectin AAL. The observation demonstrates that this recognition mode is commonly adopted by TF-binding galectins, either as endogenous or exogenous ones. The detailed structural comparisons between Gal-1 and Gal-3 CRD and mutagenesis experiments reveal that a pentad residue motif (51AHGDA55) at the loop (g1-L4) connecting β-strands 4 and 5 of Gal-1 produces a serious steric hindrance for TF binding. This motif is the main structural basis for Gal-1 with the low affinity to TF antigen. These findings provide the intrinsic structural elements for regulating the TF-binding activity of Gal-1 in some special conditions and also show certain target and approach for mediating some tumor-related bioactivities of human galectins.
5-Hydroxy-1-(3-hydroxy-2-naphthoyl)-3,5-dimethyl-2-pyrazoline
Yuting Chen,Da-Cheng Li,Yuehua Zhu,Da-Qi Wang
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808023027
Abstract: In the title molecule, C16H16N2O3, intramolecular O—H...O hydrogen bonds influence the molecular conformation. Intermolecular O—H...O hydrogen bonds [O...O = 2.922 (2) ] link the molecules into centrosymmetric dimers. Weak intermolecular C—H...O interactions assemble these dimers into layers parallel to the bc plane.
[3-Hydroxy-N′-(2-oxidobenzylidene)-2-naphthohydrazidato-κ3O,N,O′]tris(pyridine-κN)nickel(II) pyridine trisolvate
Shi-Zhu Sun,Wen-Jun Kang,Da-Cheng Li,Da-Qi Wang
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808002900
Abstract: The asymmetric unit of the crystal structure of the title complex, [Ni(C18H12N2O3)(C5H5N)3]·3C5H5N, contains two independent NiII complex molecules and six uncoordinated pyridine molecules. Each NiII atom is coordinated by two O and four N atoms, from three pyridine and a chelating 3-hydroxy-N′-(2-oxidobenzylidene)-2-naphthohydrazide dianionic ligand, with a distorted octahedral geometry. Intramolecular O—H...N hydrogen bonding exists in both complex molecules but no intermolecular hydrogen bonding is observed in the crystal structure.
(Methanolato)(pyridine)[N2,N2′-(pyridine-2,6-diyldicarbonyl)diacetohydrazide(2–)]iron(III) methanol solvate
Quan-Fu Cao,Jian-Min Dou,Da-Cheng Li,Da-Qi Wang
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536807060862
Abstract: In the title complex, [Fe(C11H10N5O4)(CH3O)(C5H5N)]·CH4O, the FeIII ion has a distorted pentagonal-bipyramidal geometry. In the crystal structure, molecules are linked into one-dimensional chains along [1overline{1}overline{1}] via intermolecular O—H...O and N—H...O hydrogen bonds.
Bis[μ-4-amino-3,5-bis(hydroxymethyl)-1,2,4-triazole]bis{bis[4-amino-3,5-bis(hydroxymethyl)-1,2,4-triazole]nickel(II)} tetranitrate methanol disolvate
Yu-Peng Pan,Da-Cheng Li,Da-Qi Wang
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536807064148
Abstract: The title complex, [Ni2(C4H8N4O2)6](NO3)4·2CH4O, contains a centrosymmetric binuclear nickel(II) complex bridged by a pair of 4-amino-3,5-bis(hydroxymethyl)-1,2,4-triazole ligands. The separation between the NiII atoms is 3.962 (1) . The Ni atoms are in a slightly distorted octahedral coordination. Intermolecular N—H...O, N—H...N and O—H...O hydrogen bonds connect the ligands, solvent molecules and nitrate ions.
N,N′-Disalicyloylhydrazine
Yu-Ting Chen,Da-Cheng Li,Da-Qi Wang,Yue-Hua Zhu
Acta Crystallographica Section E , 2008, DOI: 10.1107/s160053680706312x
Abstract: The approximately planar molecule of the title compound, C14H12N2O4, is centrosymmetric and has an E configuration with respect to the N—N bond. This compound adopts the ketoamine form with C=O and C—N distances of 1.233 (3) and 1.331 (4) , respectively. Adjacent molecules are assembled into a two-dimensional supramolecular structure parallel to the (101) plane via intermolecular O—H...O hydrogen bonds.
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