N,N-bidentate 1:2 complexes of nickel(II) with various N,N,O-terdentate 2-(2-pyridylazo)phenolic ligands was detected spectrophotometrically in ethyl acetate and was examined with respect to the influences of Bronsted bases, the counter anions in the nickel(II) salts employed, solvent basicity, and the steric requirements around the donor nitrogen atoms in the ligand in the 1:2 complex. It is concluded
在乙酸乙酯中通过分光光度法检测镍 (II) 与各种 N,N,O-三齿 2-(2-吡啶偶氮) 酚配体的 N,N-二齿 1:2 配合物的形成,并检查了布朗斯台德碱、所用镍 (II) 盐中的抗衡阴离子、溶剂碱度以及 1:2 配合物中配体中供体氮原子周围的空间要求。得出的结论是,溶液中 N,N-二齿复合物的稳定性主要取决于 NiX2 和溶剂中抗衡阴离子 X 的碱度。在1-(2-吡啶偶氮)-2-萘酚的情况下,由于萘环的空间位阻高,即使在二恶烷等低碱度的溶剂中也未观察到N,N-二齿络合物的形成.
The formation of a new N,N-bidentate complex of nickel(II) perchlorate with an N,N,O-terdentate ligand, 4-(4-methyl-2-pyridylazo)resorcinol (4-MePAR), was first detected in dioxane spectrophotometrically. The stability of the N,N-bidentate species in dioxane is strongly affected by the presence of a proton acceptor such as water, ethanol, imidazole, and Cl−, which promote the coordination of the ortho phenolic oxygen in the ligand to form the N,N,O-terdentate complex. The new complex was isolated from dioxane solution and identified to be an N,N-bidentate complex salt, [Ni(4-mepar)2](ClO4)2, having two counter ions, ClO4−. A distortedplanar configuration of the complex was suggested on the basis of IR, X-ray photoelectron spectroscopic, and magnetic measurements.