Coordination complexes of amino acids: Preparation and properties of some Amino-acidatobis(acetylacetonato)cobalt(III) and Bis(amino-acidato)(acetylacetonato)cobalt(III) complexes

1968 ◽  
Vol 21 (3) ◽  
pp. 679 ◽  
Author(s):  
SH Laurie
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Absorption Band ◽  
Absorption Spectra ◽  
Coordination Complexes ◽  
Optically Active ◽  
Ultraviolet Absorption ◽  
Visible Absorption ◽  
Molecular Weights ◽  
Cotton Effects

Complexes of the type [Co(acac)2(aa)] have been synthesized, in which the amino acid is DL- and L-phenylalanine, L-valine, L-leucine, L-proline, DL-, L-,and D-alanine, and glycine. The complexes were characterized by means of analyses, molecular weights, and their infrared, visible, and ultraviolet absorption spectra. During the syntheses several of the bis(amino-acidato) complexes, [Co(acac)(aa)2], were also formed; the L-phenylalanine and glycine complexes were isolated and characterized. The complexes prepared from the optically active amino acids exhibited Cotton effects in the region of the visible absorption band (lA1g, + 1T1g). These effects have been attributed to induced asymmetry rather than stereoselectivity. Amino acids of the same configuration gave rise to Cotton effects of the same sign, ie. (-)590-[Co(acac)2(L-aa)], (-)6590-[Co(acac)(L-aa)2], and (+)590-[Co(acac),(D-aa)].

Circular dichroism spectra of amino acid complexes. II. Chelated amino acid complexes with the CoN5O chromophore

1970 ◽  
Vol 23 (9) ◽  
pp. 1735 ◽  
Author(s):  
CJ Hawkins ◽  
PJ Lawson
Keyword(s):  
Amino Acids ◽  
Circular Dichroism ◽  
Amino Acid ◽  
Visible Region ◽  
Optically Active ◽  
Circular Dichroism Spectra ◽  
Amino Acid Complexes ◽  
Similar Series ◽  
Cotton Effects ◽  
Circular Dichroïsm

The circular dichroism spectra of a series of optically active (α-aminocarboxylato)tetraamminecobalt(111) complexes have been measured in aqueous solution, and in the presence of salts of polarizable anions. The observed spectra in the visible region have been analysed to determine the signs of the Cotton effects of the three components of the 1A1g ↔ 1T1g cobalt(111) transition. For L-amino acids, the transition with A2g(D4h) parentage is negative, and the two transitions with Eg(D4h) parentage have opposite signs. Published circular dichroism spectra of complexes of the type [Co(en)2(L-am)]2+ were similarly interpreted in terms of a perturbed tetragonal chromophore, and it was shown that the vicinal effect of the L-amino acids imposed the same signs onto the component transitions as for the tetraammines and for a similar series of pentaamminecobalt(111) complexes.

scholarly journals Amino Acids Sequence Based in Silico Analysis of RuBisCO (Ribulose-1,5 Bisphosphate Carboxylase Oxygenase) Proteins in Some Carthamus L. ssp.

2017 ◽  
Vol 9 (2) ◽  
pp. 204-208 ◽  
Author(s):  
Emre SEVİNDİK
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Average Length ◽  
3D Structure ◽  
Three Dimensional ◽  
In Silico Analysis ◽  
Bisphosphate Carboxylase ◽  
Molecular Weights ◽  
Acid Ratio ◽  
Important Enzyme

RuBisCO is an important enzyme for plants to photosynthesize and balance carbon dioxide in the atmosphere. This study aimed to perform sequence, physicochemical, phylogenetic and 3D (three-dimensional) comparative analyses of RuBisCO proteins in the Carthamus ssp. using various bioinformatics tools. The sequence lengths of the RuBisCO proteins were between 166 and 477 amino acids, with an average length of 411.8 amino acids. Their molecular weights (Mw) ranged from 18711.47 to 52843.09 Da; the most acidic and basic protein sequences were detected in C. tinctorius (pI = 5.99) and in C. tenuis (pI = 6.92), respectively. The extinction coefficients of RuBisCO proteins at 280 nm ranged from 17,670 to 69,830 M-1 cm-1, the instability index (II) values for RuBisCO proteins ranged from 33.31 to 39.39, while the GRAVY values of RuBisCO proteins ranged from -0.313 to -0.250. The most abundant amino acid in the RuBisCO protein was Gly (9.7%), while the least amino acid ratio was Trp (1.6 %). The putative phosphorylation sites of RuBisCO proteins were determined by NetPhos 2.0. Phylogenetic analysis revealed that RuBisCO proteins formed two main clades. A RAMPAGE analysis revealed that 96.3%-97.6% of residues were located in the favoured region of RuBisCO proteins. To predict the three dimensional (3D) structure of the RuBisCO proteins PyMOL was used. The results of the current study provide insights into fundamental characteristic of RuBisCO proteins in Carthamus ssp.

scholarly journals The reactions of α-amino acids and α-amino acid esters with high valent transition metal halides: synthesis of coordination complexes, activation processes and stabilization of α-ammonium acylchloride cations

RSC Advances ◽  
2017 ◽  
Vol 7 (17) ◽  
pp. 10158-10174 ◽  
Author(s):  
Lorenzo Biancalana ◽  
Marco Bortoluzzi ◽  
Eleonora Ferretti ◽  
Mohammad Hayatifar ◽  
Fabio Marchetti ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transition Metal ◽  
Transition Metals ◽  
Coordination Compounds ◽  
Coordination Complexes ◽  
Amino Acid Esters ◽  
Metal Halides ◽  
High Valent ◽  
Acid Esters

We describe the synthesis of rare coordination compounds of early transition metals with α-amino acids and α-amino acid esters, the unusual C–C dimerization ofl-proline, and the stabilization of reactive α-ammonium acylchloride cations.

SPECTROSCOPIC STUDIES OF KETO–ENOL EQUILIBRIA: PART 2. ANOMALOUS ULTRAVIOLET ABSORPTION SPECTRA OF SATURATED 1,2-DICYANO ESTERS

1962 ◽  
Vol 40 (12) ◽  
pp. 2272-2277 ◽  
Author(s):  
T. R. Kasturi ◽  
B. N. Mylari ◽  
A. Balasubramanian ◽  
C. N. R. Rao
Keyword(s):  
Absorption Band ◽  
Absorption Spectra ◽  
Spectroscopic Studies ◽  
Anomalous Behavior ◽  
Enol Form ◽  
Ultraviolet Absorption ◽  
Polar Solvents ◽  
Solvent Dependence

1,2-Dicyano esters show an absorption band around 245 mμ in alcoholic solutions which is not found in non-polar and other polar solvents. This anomalous behavior has been found to be due to the unusual solvent dependence of the equilibrium between the keto and enol forms. The intensity of the absorption band in alcoholic solutions decreases with increase in concentration of the 1,2-dicyano ester, indicating association of the enol form. The keto–enol equilibrium is also found to be sensitive to the substituent R of the alcohol ROH.

ABSORPTION SPECTRA AND CONFIGURATION OF SOME AMINE COMPLEXES OF COPPER (II) ACETATE

1966 ◽  
Vol 44 (8) ◽  
pp. 895-898 ◽  
Author(s):  
Gopal Narain
Keyword(s):  
Molecular Weight ◽  
Absorption Spectra ◽  
Coordination Complexes ◽  
Single Band ◽  
Aliphatic Amines ◽  
Conductivity Measurements ◽  
Visible Absorption ◽  
Amine Complexes ◽  
Constituent Elements ◽  
Absorption Measurements

Coordination complexes of copper(II) acetate, ammonia, aliphatic amines, and pyridine have been prepared. Molecular formulae on the basis of percentage of constituent elements were found to be Cu(OAc)2(am)2, where OAc represents acetate ion and am any amine used. Conductivity measurements in nitrobenzene and formamide indicate that the complexes are nonelectrolytes and thus it is suggested that acetate ions are also coordinated. Molecular weight measurements in the same solvents confirm this. Visible absorption measurements in formamide show a single band at about 635 mμ.

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