Studies of cobalt(III) complexes of thiosemicarbazide

1970 ◽  
Vol 48 (15) ◽  
pp. 2327-2333 ◽  
Author(s):  
Kenneth K. W. Sun ◽  
Roland A. Haines
Keyword(s):  
Optically Active ◽  
Optical Rotatory Dispersion ◽  
Bond Rupture ◽  
Ionic Form ◽  
Optical Rotatory ◽  
Geometric Isomers ◽  
Complex Ions ◽  
Active Complex ◽  
Cis And Trans ◽  
Rupture Mechanism

cis and trans geometric isomers of low spin octahedral cobalt(III) complexes containing either thiosemicarbazide (Htsc) or its anion (tsc) have been prepared and electronic spectra are presented and discussed. For the ionic form [Co(Htsc)3]3+ both isomers were resolved and absolute configurations were assigned on the basis of optical rotatory dispersion and circular dichroism measurements. The interconversion of these optically active complex ions in aqueous solution was studied and a bond rupture mechanism is proposed to account for the observed inversion and isomerization.

THE EFFECTS OF OPTICALLY INACTIVE IONS ON THE ROTATORY DISPERSION OF ASYMMETRIC COMPLEX IONS

1961 ◽  
Vol 39 (11) ◽  
pp. 2360-2370 ◽  
Author(s):  
Marvin J. Albinak ◽  
Dinesh C. Bhatnagar ◽  
Stanley Kirschner ◽  
Anthony J. Sonnessa
Keyword(s):  
Water Solution ◽  
Inorganic Compounds ◽  
Optically Active ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Complex Ions ◽  
Ionic Charge ◽  
Sodium Potassium ◽  
Active Anion

Considerable interest in the optical rotatory dispersion of asymmetric organic and inorganic compounds and its application to the elucidation of their structures has arisen in recent years. In order to study the effects of optically inactive ions on the rotatory dispersion of asymmetric complex ions, a series of salts was prepared of two active cations: levo cis-oxalato-bis(ethylenediamine)cobalt(III) and levo tris(ethylenediamine)chromium(III). Salts prepared included the fluoride, chloride, bromide, iodide, tetrafluoroborate, perchlorate, sulphate, and phosphate. In order to study this effect on an optically active anion, the lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, and barium salts of dextro and levo tris(oxalato)rhodate(III) were also prepared. Rotatory dispersion curves and absorption spectra were obtained for all salts in water solution. A comparison of the curves within a series showed definite trends in changes of wavelength and intensity of maxima of rotation and absorption with changes in both the ionic charge/size ratio (ionic potential) and polarizability of the optically inactive ions.

A. General principles Introductory remarks

1967 ◽  
Vol 297 (1448) ◽  
pp. 2-2
Keyword(s):  
Circular Dichroism ◽  
Royal Society ◽  
General Relation ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Complex Ions ◽  
Conformational Effects ◽  
The Subject ◽  
Circular Dichroïsm

This special issue of Proceedings gives the papers presented at a two-day Discussion Meeting held on 10 and 11 March 1966 in the rooms of the Royal Society in Burling­ton House. The meeting was organized at the suggestion of the Council of the Royal Society in view of the fact that the subject was specially ripe for discussion at the present time. The general relation between optical activity and stereochemistry was discovered more than a century ago. Since that time the phenomenon has been used extensively in the elucidation of chemical structure. However, a satisfactory understanding of the electronic basis of rotatory dispersion and circular dichroism of disymmetric molecules and complex ions has only recently been forthcoming. Modern develop­ments in the theory of spectra, together with the availability of commercial instru­ments for the study of the subject, have enabled investigators to predict absolute configurations of molecules. The techniques of circular dichroism and optical rotatory dispersion have great value also in the determination of relative sterochemistry and in the study of conformational effects. These factors have caused a marked resurgence of interest in the subject and hence it is timely to provide an opportunity for a discussion on the principles of circular dichroism, and some of the more fundamental aspects of optical rotatory dispersion. The aim of this Discussion will be to enunciate these principles, their origin and the likely trend of develop­ment rather than to survey their application to individual problems of structure.

Configuration of echinulin. II. Optical rotatory dispersion of echinulin, hydroechinulin, and the stereoisomeric 3-methyl-6(indolyl-3-methyl)-piperazine-2,5-diones

1969 ◽  
Vol 47 (11) ◽  
pp. 2069-2074 ◽  
Author(s):  
R. Nakashima ◽  
G. P. Slater
Keyword(s):  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Cis And Trans

The optical rotatory dispersion spectra of echinulin and hydroechinulin have been compared with the spectra of the 4 stereoisomers of cyclo-alanyltryptophan. The results indicate appreciable differences in the spectra of the cis- and trans-piperazinediones and that echinulin has the cyclo-L-alanyl-L-tryptophan configuration.

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