Coordination chemistry of the tetrakis(2-hydroxyphenyl)ethene support mimic — Polymetallic magnesium, aluminum, and titanium derivatives

2005 ◽  
Vol 83 (6-7) ◽  
pp. 922-928 ◽  
Author(s):  
Udo H Verkerk ◽  
Robert McDonald ◽  
Jeffrey M Stryker
Keyword(s):  
Coordination Chemistry ◽  
Crystal Structures ◽  
Coordination Complexes ◽  
Conformational Flexibility ◽  
Titanium Complexes ◽  
Dimeric Complexes ◽  
Aluminum Complexes ◽  
Magnesium Complexes

The crystal structures of magnesium, aluminum, and titanium coordination complexes of the structurally preorganized tetrakis(2-hydroxyphenyl)ethene are reported. As a result of the absence of steric shielding and the conformational flexibility of the ligand, pseudo-dimeric complexes are formed instead of crown- or raft-like compounds. The unsubstituted tetrakis(2-hydroxyphenyl)ethene ligand thus emulates the complexation characteristics of the sterically open calix[4]arene system.Key words: coordination chemistry, polymetallic, titanium complexes, magnesium complexes, aluminum complexes, tetrakis(2-hydroxyphenyl)ethene ligands, crystal structures.

Coordination chemistry of sulfamethizole: crystal structures of [Cu(sulfamethizolate)2(py)2(OH2)]·H2O, [M(sulfamethizolate)2(py)2(OH2)2] [M=Co and Ni] and {Cu(sulfamethizolate)2(dmf)2}∞

Polyhedron ◽  
2000 ◽  
Vol 19 (15) ◽  
pp. 1859-1866 ◽  
Author(s):  
Elisa Borrás ◽  
Gloria Alzuet ◽  
Joaquı́n Borrás ◽  
Juan Server-Carrió ◽  
Alfonso Castiñeiras ◽  
...  
Keyword(s):  
Coordination Chemistry ◽  
Crystal Structures

Coordination Chemistry ofN,N,N′,N′-Tetraethylpyridine-2,6-dithiocarboxamide (S-dept) - X-ray Crystal Structures and Magnetic Properties of [Co(S-dept)X2] (X = Br, I, and NCS)

2005 ◽  
Vol 2005 (19) ◽  
pp. 3884-3893 ◽  
Author(s):  
Ramesh Kapoor ◽  
Ashok Kataria ◽  
Paloth Venugopalan ◽  
Pratibha Kapoor ◽  
Geeta Hundal ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Coordination Chemistry ◽  
Crystal Structures ◽  
X Ray

X-ray studies on crystalline complexes involving amino acids and peptides. XL. Conformational variability, recurring and new features of aggregation, and effect of chirality in the malonic acid complexes of DL- and L-arginine

2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Crystal Structures ◽  
Malonic Acid ◽  
Conformational Flexibility ◽  
X Ray ◽  
Conformational Variability ◽  
Aggregation Pattern ◽  
Positively Charged

The crystal structures of the complexes of malonic acid with DL- and L-arginine, which contain positively charged argininium ions and negatively charged semimalonate ions, further demonstrate the conformational flexibility of amino acids. A larger proportion of folded conformations than would be expected on the basis of steric consideration appears to occur in arginine, presumably because of the requirements of hydrogen bonding. The aggregation pattern in the DL-arginine complex bears varying degrees of resemblance to patterns observed in other similar structures. An antiparallel hydrogen-bonded dimeric arrangement of arginine, and to a lesser extent lysine, is a recurring motif. Similarities also exist among the structures in the interactions with this motif and its assembly into larger features of aggregation. However, the aggregation pattern observed in the L-arginine complex differs from any observed so far, which demonstrates that all the general patterns of amino-acid aggregation have not yet been elucidated. The two complexes represent cases where the reversal of the chirality of half the amino-acid molecules leads to a fundamentally different aggregation pattern.

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