The heavy lanthanide ions(Dy,Ho,Er,Tm and Yb)were used to probe the conformation of L-arginine in aqueous solution.The results showed that the contact contribution to the observed^(13)C paramagnetic shift is very smal...The heavy lanthanide ions(Dy,Ho,Er,Tm and Yb)were used to probe the conformation of L-arginine in aqueous solution.The results showed that the contact contribution to the observed^(13)C paramagnetic shift is very small 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 calculated geometric factors for the corresponding experimental data.In the lanthanide-L-arginine complex,the whole backbone of the ligand is located outsite the zero-dipolar shift cone of the lanthanide ion with the carboxyl group selectively coordinated to the metal.The 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 to the trans form.展开更多
The reactions of carboplatin ([Pt(NH3)2(CBDCA)], in which CBDCA is cyclobutane 1,1, dicarboxylate) with L selenomethionine (L Se MetH) and L methionine (L MetH) were investigated using electrospray mass spectroscopy (...The reactions of carboplatin ([Pt(NH3)2(CBDCA)], in which CBDCA is cyclobutane 1,1, dicarboxylate) with L selenomethionine (L Se MetH) and L methionine (L MetH) were investigated using electrospray mass spectroscopy (ESMS) and 2D HSQC NMR spectroscopy. The dominant products for both reactions are bis chelated complexes [Pt(L Se Met)2] and [Pt(L Met)2]. These results are different from those observed for the reactions of cisplatin ([PtCl2(NH3)]) with L Se MetH or L MetH, in which the main products are mono chelated complexes [PtCl(NH3)(L Se Met)] or [PtCl(NH3)(L Met)]. This work provides insights into the differences between cisplatin and carboplatin in their reactivity and mechanism of reaction.展开更多
基金This project was supported by the Natural Science Foundation of China
文摘The heavy lanthanide ions(Dy,Ho,Er,Tm and Yb)were used to probe the conformation of L-arginine in aqueous solution.The results showed that the contact contribution to the observed^(13)C paramagnetic shift is very small 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 calculated geometric factors for the corresponding experimental data.In the lanthanide-L-arginine complex,the whole backbone of the ligand is located outsite the zero-dipolar shift cone of the lanthanide ion with the carboxyl group selectively coordinated to the metal.The 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 to the trans form.
文摘The reactions of carboplatin ([Pt(NH3)2(CBDCA)], in which CBDCA is cyclobutane 1,1, dicarboxylate) with L selenomethionine (L Se MetH) and L methionine (L MetH) were investigated using electrospray mass spectroscopy (ESMS) and 2D HSQC NMR spectroscopy. The dominant products for both reactions are bis chelated complexes [Pt(L Se Met)2] and [Pt(L Met)2]. These results are different from those observed for the reactions of cisplatin ([PtCl2(NH3)]) with L Se MetH or L MetH, in which the main products are mono chelated complexes [PtCl(NH3)(L Se Met)] or [PtCl(NH3)(L Met)]. This work provides insights into the differences between cisplatin and carboplatin in their reactivity and mechanism of reaction.
