Syntheses, structures and properties of chiral dinuclear zinc complexes with Schiff-base ligands

Two couples of enantiomerically chiral dinuclear zinc complexes with Schiff-base ligands, [Zn2(R-L1)3](ClO4)·H2O (1) and [Zn2(S-L1)3](ClO4)·H2O (2), [Zn2(R-L2)3](ClO4) (3) and [Zn2(S-L2)3](ClO4) (4) (R-L1 or S-L1 = R- or S-3-methoxy-6-(((methyl-2-pyridinylmethyl) imino)methyl)-Phenol, R-L2 or S-L2 = R- or S-1-((1-(pyridin-2-yl)ethylimino)methyl) naphthalen-2-ol), were synthesized and characterized. The strong solid-state fluorescence emissions were observed at around 490 nm for 1 and 2 and 580 nm for 3 and 4 at room temperature, respectively, which are attributed to the intraligand charge-transfer excite state. The fluorescence emissions of 3 and 4 exhibit obvious red-shift relative to 1 and 2.