Palladium(II) chloride complexes with 1,2,4-triazolo[1,5-a]pyrimidines: X-ray, 15N–1H NMR and 15N CP MAS studies
作者:Edward Szłyk、Antoni Grodzicki、Leszek Pazderski、Andrzej Wojtczak、Janusz Chatłas、Grzegorz Wrzeszcz、Jerzy Sitkowski、Bohdan Kamieński
DOI:10.1039/a908469j
日期:——
Palladium(II) complexes of formula [Pd(tp)2Cl2] 1, [Pd(dmtp)2Cl2]·H2O 2, [Pd(dptp)2Cl2]·H2O 3, [Pd(dbtp)2Cl2] 4a, 4b, where tp = 1,2,4-triazolo[1,5-a]pyrimidine, dmtp = 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine, dptp = 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine, dbtp = 5,7-di-tert-butyl-1,2,4-triazolo[1,5-a]pyrimidine, were prepared. The crystal structure of [Pd(dbtp)2Cl2]·0.5 C2H5OH 4c was resolved by X-ray diffraction analysis, exhibiting monomeric, nearly square-planar cis geometry and N(3) co-ordination. A small tetrahedral distortion from the co-ordination plane was observed. The PdâCl distances are 2.276(1) and 2.283(1) Ã
, and PdâN 2.042(3) and 2.040(3) Ã
. Spectroscopic measurements (UV-VIS, IR, NMR) suggested analogous structures for 1, 2 and 3. Compounds 4a and 4b are most likely rotational isomers in solution and distortional isomers in the solid state. 15Nâ1H heteronuclear correlation NMR was measured for 2, 4a and 4b whereas 1 and 3 were characterized with 13C and 15N CP MAS. Significant shielding of the co-ordinated N(3) and adjacent C(2) or C(3a) nuclei was observed.
钯(II)络合物,结构式为 [Pd(tp)2Cl2] 1、[Pd(dmtp)2Cl2]·H2O 2、[Pd(dptp)2Cl2]·H2O 3、[Pd(dbtp)2Cl2] 4a、4b ,其中 tp = 1,2,4-三唑并[1,5-a]嘧啶,dmtp = 5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶,dptp = 5 ,7-二苯基-1,2,4-三唑并[1,5-a]嘧啶, dbtp=5,7-二叔丁基-1,2,4-三唑并[1,5-a]嘧啶,准备好了。通过X射线衍射分析解析了[Pd(dbtp)2Cl2]·0.5 C2H5OH 4c的晶体结构,表现出单体、近正方形平面的顺式几何结构和N(3)配位。观察到与协调平面的小四面体扭曲。 Pd-Cl 距离为 2.276(1) 和 2.283(1) ×,Pd-N 距离为 2.042(3) 和 2.040(3) ×。光谱测量(UV-VIS、IR、NMR)表明 1、2 和 3 具有类似的结构。化合物 4a 和 4b 最有可能是溶液中的旋转异构体和固态中的扭曲异构体。 2、4a 和 4b 测量了 15N→1H 异核相关 NMR,而 1 和 3 则用 13C 和 15N CP MAS 进行了表征。观察到配位的 N(3) 和相邻的 C(2) 或 C(3a) 核的显着屏蔽。