Effects of Acidity on Nitrogen-heterocyclic Compounds with Rare Earth Coordination and the Structure of Protonated Phenanthroline

摘要

2,3-bis(2-pyridyl)-5,6-dihydropyrazine and a protonated phenanthroline (Phen) have been synthesized and the structure of protonated Phen is established by X-ray diffraction single crystal structure analysis. The coordination reactions of Phen, 2,2'- bipyridine and 2,3-bis(2-pyridyl)-5,6-dihydropyrazine with rare earth ions in low pH have been studied. The results show that 2,3-bis(2-pyridyl)-5,6-dihydropyrazine is hydrolyzed to be 2,2'-pyridil and protonated ethylenediamine. Meanwhile, Phen combines with proton, which results that nitrogen atoms can not coordinate with rare earth ions. The molecular formula of protonated Phen is C_(12)H_8N_2HCl-H_2O. It crystallizes in the triclinic space group P -1 (2), with a = 7.1212(14) A, b = 7.2786(15) A, c = 20.817(4) A, a = 90.00°, (3 = 96.69(3) °, γ = 90.00 °, V = 1071.65(379) A~3, Z = 4.