The competition of basicity and steric factors in the nitroxide donor functions in metal complexes: The study of M(hfac)2(M = Co, Ni) adducts with 3-imidazoline nitroxides
作者:Alexei B. Burdukov、Victor I. Ovcharenko、Renad Z. Sagdeev、Natalie V. Pervukhina、Vladimir N. Ikorskii、Igor A. Kirilyuk、Igor A. Grigor'ev
DOI:10.1016/0277-5387(96)00159-3
日期:1996.9
coordination for steric reasons. In M(hfac)2(H2O)2L22 the nitroxide moieties are H-bonded to the coordinated water molecules through the imine nitrogen atoms and methoxy oxygen atoms. The nitroxide L2 is unstable in the presence of Co(hfac)2 and on removal of water decomposes to yield the adduct with nitrone Co(hfac)2L23, L3 = 2,2-dimethyl-5-methoxy-4-phenyl-2H-imidazol 1-oxide. The complexes M(hfac)2L21 demonstrate
相似的氮氧化物2,2,5,5-四甲基-4-苯基-3-咪唑啉-1-氧基(L 1)和2,2-二甲基-5,5-二甲氧基-4-苯基-3-咪唑啉-1 -与钴和六氟乙酰丙酮化镍反应生成的不同组成的配合物生成的-氧基(L 2):M(hfac)2 L 2 1和M(hfac)2(H 2 O)2 L 2 2。在M(hfac)2 L 2 1配合物中,氮氧化物通过氮氧化物氧与金属离子键合,但由于空间原因,亚胺氮不参与配位。在M(hfac)2(H 2 O)2中在L 2 2中,氮氧化物部分通过亚胺氮原子和甲氧基氧原子与键合的水分子氢键结合。氮氧化物L 2在Co(hfac)2的存在下是不稳定的,并且在除去水时分解,从而生成与亚硝基Co(hfac)2 L 2 3的加合物,L 3 = 2,2-二甲基-5-甲氧基-4 -苯基-2 H-咪唑1-氧化物。配合物M(hfac)2 L 2 1表现出金属离子与氮氧化物之间的强反铁磁耦合。