2-羟基-3-对溴苯基马来酰亚胺的稀土络合物的合成及其研究

Investigation on the Rare Earth Complexes of 2-Hydroxy-3-p-Bromophenyl-Maleimide

用2-羟基-3-对溴苯基马来酰亚胺的钠盐与无水RECl_3在DMSO溶剂中氧气氛下反应,制得了13种相应的稀土络合物,通过IR、UV、~1H NMR、^(13)C NMR等波谱方法对其结构进行了测定,归属了波谱吸收峰,表明该络合物是通过去质子羟基氧与RE^(3+)成键,邻位羰基不参与配位,并讨论了RE—O键的性质,络合物的组成为REL_3·nH_2O(RE=La-Lu,不包括Pm,Yb;n=1～4)。

2-Hydroxy-3-p-bromophenyl-maleimide (HBPMI) has two acidic functional sites including the ring nitrogen atom and the 3-hydroxy group. Thirteen rare earth metal complexes were prepared by the reactions of HBPMI sodium salt with REC13 in DMSO under Ar atmosphere. There complexes were studied by means of IR, UV, 'H NMR, 13C NMR and elemental analysis. The results indicate that it is the deprotonated hydroxy group of the HBPMI that bonds with RE3+, but not the nitrogen. Participation of the adjacent carbonyl in coordination was not found. The composition of the complexes is RECl3 .nH2O(RE=La-Lu, except Pm, Yb; L is the HBPMI-oxide anion, n=2-4). RE-O bond is considered to be ionic with some degrees of covalent character. The shift rule of the RE-O bond strength does not conform the rule of tetrad effect. It was found that the conjugation between p-bromophenyl and maleimide moiety in the HBPMI-oxide anion of the rare earth complexes is stronger than in the HBPMI itself, and that the charge is transferred from the negative oxygen to the p-bro-mophenyl moiety.