The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O a...The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.展开更多
The equilibrium solubility of the LaCl3 CdCl2 (9.7%)HCl H2O quaternary system at 298K was determined and the phase diagram was constructed. The results show that the system is complicated with four equilibrium solid p...The equilibrium solubility of the LaCl3 CdCl2 (9.7%)HCl H2O quaternary system at 298K was determined and the phase diagram was constructed. The results show that the system is complicated with four equilibrium solid phases CdCl2·H2O, 8CdCl2·LaCl3·16H2O(8∶1 type), 4CdCl2·LaCl3·12H2O(4∶1 type) and LaCl3·7H2O, respectively. The two new compounds 8CdCl2·LaCl3·16H2O(8∶1 type) and 4CdCl2·LaCl3·12H2O(4∶1 type) are congruently soluble in ～9.7%HCl H2O medium and have not yet been reported in literatures. Both compounds have been prepared from the system and have been characterized by XRD, TG DTG and DSC.展开更多
文摘The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.
文摘The equilibrium solubility of the LaCl3 CdCl2 (9.7%)HCl H2O quaternary system at 298K was determined and the phase diagram was constructed. The results show that the system is complicated with four equilibrium solid phases CdCl2·H2O, 8CdCl2·LaCl3·16H2O(8∶1 type), 4CdCl2·LaCl3·12H2O(4∶1 type) and LaCl3·7H2O, respectively. The two new compounds 8CdCl2·LaCl3·16H2O(8∶1 type) and 4CdCl2·LaCl3·12H2O(4∶1 type) are congruently soluble in ～9.7%HCl H2O medium and have not yet been reported in literatures. Both compounds have been prepared from the system and have been characterized by XRD, TG DTG and DSC.
