Multifunctional Zn(II)-Yb(III) complex enantiomers showing second-harmonic generation, near-infrared luminescence, single-molecule magnet and proton conduction

A new pair of multifunctional Zn(II)-Yb(III) complex enantiomers based on a chiral amine-phenol ligand, [YbZn2(SS/RR-L)2(H2O)4](ClO4)3•5H2O (S-1 and R-1) [H2L = ((SS/RR)-cyclohexane-1,2-diylbis(azanediyl))-bis(methylene))-bis(2-methoxyphenol))], were synthesized and structurally characterized. In S-1 and R-1, the linear Zn(II)-Yb(III)-Zn(II) metal core is bridged by the phenolate oxygen atoms. Enantiomers S-1 and R-1 show chiroptical activity. Complex S-1 exhibits second-harmonic generation (SHG) and YbIII characteristic emissions in the near-infrared (NIR) region. Magnetic studies indicate that S-1 shows single-molecule magnet (SMM) behaviour. Moreover, S-1 displays a high proton conductivity of 1.55× 10−4 S•cm−1 at room temperature under 100% relative humidity (RH), which benefits from a 1D H-bonded chain constructed by NH groups of the chiral amine-phenol ligand, water molecules and perchlorate anions (ClO4–). The combination of such five-functions including chiral, nonlinear optical, magnetic, luminescent and proton-conductive properties in molecule-based materials may provide a great potential for the application in smart multifunctional devices.