论文部分内容阅读
The heavy lanthanide ions(Dy,Ho,Er,Tm and Yb)were used to probe the conformation of L-arginine inaqueous solution.The results showed that the contact contribution to the observed~(13)C paramagnetic shift is verysmall for nuclei four or more bonds away from the bound lanthanide ion and it is significant for those in closeproximity to the lanthanide ion.The overall conformation of L-arginine was established by fitting the calculatedgeometric factors for the corresponding experimental data.In the lanthanide-L-arginine complex,the wholebackbone of the ligand is located outsite the zero-dipolar shift cone of the lanthanide ion with the carboxyl groupselectively coordinated to the metal.The calculated RE-O distance is 0.21 nm for the bidentate coordinationmode and the ligand is in an extended conformation in the solution with the molecular backbone corresponding tothe trans form.
The heavy lanthanide ions (Dy, Ho, Er, Tm and Yb) were used to probe the conformation of L-arginine inaqueous solution. The results showed that the contact contribution to the observed ~ (13) C paramagnetic shift is verysmall for nuclei four or more bonds away from the bound lanthanide ion and it is significant for those in close proximity to the lanthanide ion.The overall conformation of L-arginine was established by fitting the calculatedgeometric factors for the corresponding experimental data. In the lanthanide-L-arginine complex , the wholebackbone of the ligand is located outsite the zero-dipolar shift cone of the lanthanide ion with the carboxyl group selectively coordinated to the metal. calculated RE-O distance is 0.21 nm for the bidentate coordination mode and the ligand is in an extended conformation in the solution with the molecular backbone corresponding tothe trans form.