Synthesis, crystal structures and fluorescence studies of three new Zn(II) complexes with multidentate Schiff base ligands

Abstract

Three new zinc(II) complexes Zn(L 1 ) 2 ( 1 ), Zn 2 L 2 (OAc) 3 ( 2 ) and Zn 2 L 3 (OAc) 3 ( 3 ) have been synthesized by using Zn(OAc) 2 ·2H 2 O and potentially multidentate Schiff base ligands HL 1 (2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol), HL 2 (2-((1-hydroxy-2-methyl-propan-2-ylimino)methyl)-6-methoxyphenol) and HL 3 (2-((2-hydroxypropylimino)-methyl)-6-methoxyphenol), respectively. These Schiff base ligands are the condensation product of o-vanillin and corresponding amino alcohols. All the three complexes 1 , 2 and 3 have been characterized by elemental analysis, IR, single crystal X-ray diffraction and fluorescence studies. Structural studies reveal that 1 is a mononuclear complex whereas in dinuclear complexes 2 and 3 the two Zn(II) centers are held together by deprotonated Schiff base ligands and acetates. All the synthesized complexes display intraligand (π → π*) fluorescence and can potentially serve as photoactive materials. Three blue luminescent zinc(II) complexes have been synthesized by using Zn(OAc) 2 ·2H 2 O and potentially multidentate Schiff base ligands. The structures of all the three complexes 1 , 2 and 3 have been determined by single crystal X-ray diffraction. ► Three zinc(II) complexes with blue luminescent which display intraligand (π → π*) fluorescence has been synthesized. ► The fluorescence intensity is greatly enhanced by the coordination of (ZnII) with Schiff base ligands. ► The supramolecular interactions increase the conformational rigidity of chromophore groups and thus the emission intensity is much stonger.