Metallkomplexe mit biologisch wichtigen Liganden, XXXIII. Reaktionen von α-Aminosäuren und α-Aminosäurederivaten mit Gold(III)-chlorid/ Metal Complexes with Biological Important Ligands, XXXIII. Reactions of α-Amino Acids and Derivatives there of with Gold(III) Chloride

1984 ◽  
Vol 39 (8) ◽  
pp. 1129-1134 ◽  
Author(s):  
Eberhard Ambach ◽  
Mano Mohan Singh ◽  
Ulrich Nagel ◽  
Wolfgang Beck

AbstractThe hydrochlorides of a-aminoacid esters react with Au2Cl6 in thionyl chloride to give the ammonium salts [H3NCHRCO2R′]+AuCl4- (R = H , Me, R′ = H , Me, Et). The X-ray structure of [H3NCH(Me)CO2Me]+AuCl4- has been determined. The reactions of a-aminoacids with Au2Cl6 in SOCl2 afford mixtures of ammonium tetrachloroaurate(III) salts with a-amino acids, a-amino acid chlorides or a-amino acid anhydrides as amine components. Cysteine esters reduce gold(III) to give the gold(I) compounds [AuSCH2CH(N H2)CO2R]n (R = Me, Et).

1995 ◽  
Vol 73 (7) ◽  
pp. 1164-1174 ◽  
Author(s):  
Doris Freiesleben ◽  
Kurt Polborn ◽  
Christian Robl ◽  
Karlheinz Sünkel ◽  
Wolfgang Beck

Schiff bases from ferrocene aldehyde and α-amino acidates react with PdCl2 or Na2PdCl4 to give N,O-chelate complexes (2a–e, 3). The related N-ferrocenylmethylen-α-amino acid esters give, with Pd(OAc)2, cyclopalladated acetate-bridged complexes (4a,b). N,O-chelate complexes (5–7) are obtained from Na2PdCl4 with N-ferrocenylmethyl prolinate and-alaninate as well as with N,N-dibenzyl glycinate. The ethyl ester of N,N-dibenzylglycine and Pd(OAc)2 form the cyclopalladated acetate-bridged complex 8, while the ester of N-monobenzylglycine and Na2PdCl4 affords trans-PdCl2(L)2 with a monodentate N-coordinated ligand. The structures of 2a, 4a, 5, 7, and 9 were determined by X-ray diffraction. Keywords: ferrocene, amino acids, palladium(II) complexes, crystal structures.


2002 ◽  
Vol 57 (7) ◽  
pp. 810-818 ◽  
Author(s):  
Walter Ponikwar ◽  
Peter Mayer ◽  
Wolfgang Beck

The reactions of [(η3-C3H5)2Rh-μ-Cl]2 with the anions of α-amino acids (glycine, L-alanine, L-valine, L-isoleucine, L-proline, L-phenylalanine, L-phenylglycine, L-thyrosine) afford the N,O-chelates (η3-C3H5)2Rh(α-amino carboxylate). For complex (η3-C3H5)2Rh(glycinate) dynamic behaviour in solution could be observed by 1H NMR. The structure of (η3-C3H5)2Rh(L-prolinate) was determined by X-ray diffraction.


Clay Minerals ◽  
1967 ◽  
Vol 7 (2) ◽  
pp. 167-176 ◽  
Author(s):  
W. Bodenheimer ◽  
L. Heller

AbstractSorption of an acidic, amphoteric, sulphur containing and basic α-amino-acid (glutamic acid, glycine, methionine and lysine) by copper montmorillonite was studied by chemical and X-ray methods. With glutamic acid complex formation occurs only in solution but increasing basicity of the aminoacid favours complex formation in the clay interlayers.


2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan

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.


1999 ◽  
Vol 54 (3) ◽  
pp. 385-388 ◽  
Author(s):  
Reinhold Urban ◽  
Kurt Polbom ◽  
Wolfgang Beck

α-Amino acid esters can be added to a carbonyl ligand of [CpFe(CO)3]+CF3SO3- to give the carbamoyl complexes Cp(OC)2Fe-C(O)NHCHRCO2R′ (R = H, Me, CHMe2, CH2Ph; R′ = Et, Me). This type of reaction may be useful for the marking of peptides at the amino end. The crystal structure of Cp(OC)2Fe-C(O)NHCH2CO2Et was determined by X-ray diffraction.


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