Circular dichroism of trans-dichlorocobalt(III) complexes with chiral 1,2-diamines.
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概要
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The circular dichroism (CD) spectra of <I>trans</I>-dichlorobis(diamine)cobalt(III) complexes were measured in methanol solution in the 700–200 nm region, where the diamines have the general formula of NH<SUB>2</SUB>CH(R)CH<SUB>2</SUB>NH<SUB>2</SUB>(R=isopropyl, isobutyl, <I>sec</I>-butyl, benzyl and phenyl) and belong to the <I>S</I> configuration except the phenyl-substituted one. The spectra are essentially the same as thq spectrum of the (<I>S</I>)-propylenediamine ((<I>S</I>)-pn; R= methyl) complex, except for the (<I>R</I>)-<I>C</I>-phenylethylenediamine ((<I>R</I>)-phenen) complex. The variation of the <I>C</I>-substituted alkyl groups has hardly any influence on the CD of the <I>trans</I>-[CoCl<SUB>2</SUB>(diamine)<SUB>2</SUB>]<SUP>+</SUP> type complexes, demonstrating that the vicinal contribution from the <I>C</I>-substituents can be disregarded in these compounds. The <I>trans</I>-[CoCl<SUB>2</SUB>((<I>R</I>)-phenen)<SUB>2</SUB>]<SUP>+</SUP> ion shows a CD pattern differing significantly from that of the <I>trans</I>-[CoCl<SUB>2</SUB>((<I>R</I>)-pn)<SUB>2</SUB>]<SUP>+</SUP> ion in the first absorption band region, suggesting the significance of the vicinal effect due to the <I>C</I>-substituted phenyl group. The CD curve of <I>trans</I>-[CoCl<SUB>2</SUB>((−)<SUB>D</SUB>-stien)<SUB>2</SUB>]<SUP>+</SUP> ion (stien=stilbenediamine) was found to be antimeric to that of the (<I>R</I>)-phenen complex. Taking into account the anomalous vicinal effect of the phenyl groups, the absolute configuration of the (−)<SUB>D</SUB>-stien was assigned to the (<I>S</I>,<I>S</I>) configuration.
- 公益社団法人 日本化学会の論文