Structure and Fluorescence of Three New Homodinuclear Lanthanide (III)/Schiff-base Compounds [{Ln(clapi)}2] · 2CH3CN {Ln=La, Ce, Eu; H3clapi = 2-(5-Chloride-2-hydroxyphenyl)-1,3-bis [4-(5-chloride-2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine}

Abstract

Three new homodinuclear lanthanide(III)/Schiff-base compounds [{Ln(clapi)}2] · 2CH3CN {Ln = La 1, Ce 2, and Eu 3; H3clapi = 2-(5-chloride-2-hydroxyphenyl)––1,3-bis [4-(5-chloride-2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine} have been prepared successfully by template procedure and characterized by elemental analysis, IR spectra, and the dinuclear cerium compound (2) selected as a representative was structurally characterized. The crystal system is triclinic with space group P-1, a = 10.588 A, b = 11,521(2) A, c = 13.979(3) A, α = 109.66(3)°, β = 97.77(3)°, γ = 106.33(3)°, V = 1486.2(5) A3 and Z = 1. In compound 2, each Ce atom is coordinated to four N and four O atoms from two clapi3− ligands, forming a distorted square antiprism. Two phenol oxygen atoms from the middle arms of the two heptadentate ligands as μ2-bridging connect the two Ce atoms. Compounds 1, 2 and 3 in CH2Cl2 exhibit strong blue fluorescence at room temperature, compound 3 has no typical red emission of Eu3+ at room temperature while exhibits strong red fluorescence at 77 K in CH2Cl2. Three new dinuclear lanthanide (III)/Schiff-base compounds were synthesized by template method and the structure and fluorescence of the complexes were studied.