Type Of Chiral Complex Research Articles

Chiral CE of aromatic amino acids by ligand‐exchange with zinc(II)–L‐lysine complex

A novel method of chiral ligand-exchange CE was developed with either L- or D-lysine (Lys) as a chiral ligand and zinc(II) as a central ion. This type of chiral complexes was explored for the first time to efficiently separate either individual pairs of or mixed aromatic amino acid enantiomers. Using a running buffer of 5 mM ammonium acetate, 100 mM boric acid, 3 mM ZnSO(4) x 7H(2)O and 6 mM L-Lys at pH 7.6, unlabeled D,L-tryptophan, D,L-phenylalanine, and D,L-tyrosine were well separated, giving a chiral resolution of up to 7.09. The best separation was obtained at a Lys-to-zinc ratio of 2:1, zinc concentration of 2-4 mM and running buffer pH 7.6. The buffer pH was determined to have a strong influence on resolution, while buffer composition and concentration impacted on both the resolution and peak shape. Boric acid with some ammonium acetate was an adoptable buffer system, and some additives like ethylene diamine tetraacetic acid capable of destroying the complex should be avoided. Fine-tuning of the chiral resolution and elution order was achieved by regulating the ratio of L-Lys to D-Lys; i.e. the resolution increased from zero to its highest value as the ratio ascended from 1:0 to 1:infinitive, and L-isomers eluted before or after D-isomers in excessive D- or L-Lys, respectively.

Chiral tropocoronands: Synthesis and metal complex formation

Abstract The synthesis of several chiral tropocoronands based on 1,2-cyclohexanediamine ( 7 ) and 1,2-diphenylethylenediamine ( 8 ) has been accomplished. X-ray crystallography has confirmed the structure of two metallated derivatives, Cu(II)(TC-4,cyhex) ( 9 ) and Ni(II)(TC-4,cyhex) ( 10 ), that are indicative of the types of chiral complexes that can be formed from these systems.

ChemInform Abstract: Transition‐Metal Complexes with Sulfur Ligands. Part 52. Synthesis, X‐ Ray Structure Characterization, and Reactions of (Fe(CO)(μ‐“S4”))2, a Novel Type of Chiral Complex with Relevance to Iron Oxidoreductases ( “S4”2‐ = 1,2‐Bis((2‐mercaptophenyl)thio)ethanato(2‐)).

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Transition-metal complexes with sulfur ligands. 52. Synthesis, x-ray structure characterization, and reactions of [Fe(CO)(.mu.-"S4")]2, a novel type of chiral complex with relevance to iron oxidoreductases ("S4"2- = 1,2-bis((2-mercaptophenyl)thio)ethanato(2-))

Searching for model complexes of hydrogenases and nitrogenases with chirotopic iron centers, we found that the thermal decarbonylation of [Fe(CO) 2 («S 4 »)] leads to [Fe(CO)(μ-«S 4 »)] 2 («S 4 » 2− =1,2-bis((2-mercaptophenyl)thio)ethanato(2-)). Results from the connection of two homochiral [Fe(CO)(«S 4 »)] fragments and represents a new type of chiral complex. One pair of enantiomers were characterized by X-ray structure determinations

ChemInform Abstract: Transition‐Metal Complexes with Sulfur Ligands. Part 51. Chirality and Isomerism in Binuclear Iron Complexess with Sulfur Ligands: (Fe(CO)(μ‐′S4′))2, a Novel Complex for Oxidoreductases.

AbstractIn the course of searching model complexes for nitrogenases and hydrogenases, a new type of chiral complex was discovered, represented by (II), which is formed together with its αα‐Z(RR)‐enantiomer in 70% yield by dimerization of a racemate of chiral precursor complexes, containing one CO and the S4‐ligand, which arise from (I).

Chirality and Isomerism in Binuclear Iron Complexes with Sulfur Ligands: [Fe(CO)(μ‐“S4”)]2, a Model Complex for Oxidoreductases

Metal atoms at the active centers of oxidoreductases must be chirotopic. In the course of a search for model complexes for nitrogenases and hydrogenases, a new type of chiral complex was discovered, represented by the complex 1. It was obtained by coupling two homochiral [Fe(CO)(“S4”)] fragments, and it contains Fe centers that are capable of binding σ-π ligands. This complex may thus be regarded as one segment of a metalloprotein structure. (“S4”)2⊖ = 2,2′-(ethylenedithio)dibenzene thiolate.