Quality Control of Pyrazine-2-carboxylic acid. Recently I read an article about AQUEOUS-SOLUTION; EQUILIBRIUM-CONSTANTS; CARBOXYLIC-ACIDS; URANIUM(VI); CRYSTAL; ION; CHEMISTRY; LIGAND, Authors is Lv, LN; Chen, BH; Liu, J; Chen, J; Xu, C; Yang, YQ in ROYAL SOC CHEMISTRY in [Lv, Lina; Chen, Baihua; Liu, Jun; Yang, Yanqiu] China Acad Engn Phys, Inst Nucl Phys & Chem, Mianyang 621900, Sichuan, Peoples R China; [Chen, Jing; Xu, Chao] Tsinghua Univ, Inst Nucl & New Energy Technol, Beijing 100084, Peoples R China in 2019, Cited 42. The CAS is 98-97-5. Molecular formula is C5H4N2O2, Through research, I have a further understanding and discovery of Pyrazine-2-carboxylic acid
Complexation of U(vi) with pyridazine-3-carboxylate (PDZ) and pyrazine-2-carboxylate (PAZ) was studied by spectrophotometry, potentiometry and microcalorimetry in 1.0 mol dm(-3) NaClO4. Three complexes, [UO2L](+), UO2L2(aq) and [UO2L3](-), were identified and their stability constants (log) and the corresponding formation enthalpies were determined. The thermodynamic parameters indicate that the formation of the three complexes is endothermic and driven exclusively by entropy. H-1 and C-13-NMR data provide insight into the coordination modes of the complexes which corroborate with the thermodynamic data. Ligands chelate to U(vi) via (2)(N,O) coordination mode in complexes [UO2L](+) and UO2L2(aq). The crystal structures of four U(vi) complexes, [(UO2)(PAZ)(2)(H2O)]H2O(i), [(UO2)(PDZ)(2)(H2O)](ii), [(UO2)(PDZ)(3)Na2ClO4]2H(2)O(iii), and [(UO2)(2)(PDZ)(4)(H2O)(2)]2H(2)O(iv), were determined by single-crystal X-ray diffraction and compared with the U(vi) complex with picolinate (PA) (CH6N3)[UO2(PA)(3)] in the literature. The structure data suggest that the carboxylates coordinate with uranium in O?C-O-U mode. The strengths of the U-O-C-C-N chelate cycles in the U(vi)/L complexes decrease with the trend of PA > PDZ > PAZ, which is in great agreement with the trend of thermodynamic parameters in aqueous solutions. It is interesting that in compound II two PDZ molecules coordinate with U(vi) in cis-planar positions via (2)(N,O) mode, but in other metal complexes of the three ligands having the same (2)(N,O) coordination mode the two ligand molecules are all in trans-arrangement. In the dimeric complex IV, one ligand coordinate with U(vi) in (2)(N,O) mode, while the other does it in (2)-L-(2)(O:O) mode respectively.
Quality Control of Pyrazine-2-carboxylic acid. Bye, fridends, I hope you can learn more about C5H4N2O2, If you have any questions, you can browse other blog as well. See you lster.
Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem