Lanthanide Complexes (Ce, Pr, Nd) with an Acylhydrazone Derived from 3,4-Dimethylpyrrole-2-carbohydrazide and PMBP: Syntheses, Crystal structures and Fluorescence Properties

Abstract

Three lanthanide(Ⅲ) complexes, [LnL (NO 3 ) 3 (H 2 O)][LnL (NO 3 ) 3 (CH 3 CN)]·2CH 3 CN (Ln=Ce ( 1 ), Pr ( 2 ) and Nd ( 3 )) based on L (L is derived from 3,4-dimethylpyrrole-2-carbohydrazide and PMBP) have been synthesized and characterized by elemental analyses, IR spectra and X-ray diffraction analyses. The results reveal that three complexes are isostructural and crystallize in the monoclinic, space group P 2 1 / n ( a =1.758 83(9) nm, b =1.460 61(8) nm, c =2.626 28(14) nm, β =97.800 0(10)° for 1 ; a =1.756 39(15) nm, b =1.459 97(11) nm, c =2.623 1(2) nm, β =97.771(2)° for 2 ; a =1.758 7(2) nm, b =1.463 87(17) nm, c =2.626 3(3) nm, β =97.760(2)° for 3 ). Each of them contains two kinds of independent neutral complex molecules. Concomitantly, each Ln(Ⅲ) ion is surrounded by one tridentate ligand L with NO 2 donor set, three bidentate nitrate anions and one coordination solvent molecule, thus giving a bicapped square antiprism coordination geometry. In addition, in CH 3 CN solution, complexes 1~3 exhibit different fluorescence emission from that of the ligand L probably due to a CHEF (chelation enhancement of the fluorescence emission) effect. CCDC: 1439568, 1 ; 1439569, 2 ; 1439570, 3 .