A pair of new chiral polyoxovanadates with decent NLO properties

Abstract

Two pure enantiomers of polyoxovanadate clusters [(L-/D-C₄O₆H₂)₂V₄O₈]·2C₆N₂H₁₈ (abbreviated as 1-L and 1-D) have been synthesized by a two-step method. During the two-step synthesis process, we first carried out the solvothermal synthesis and then evaporated the solvent, ending up with orange-yellow crystals. The unique chiral architectures are built up by a single chiral ligand (tartaric acid) and polyoxovanadium. The chiralities of the products were confirmed by circular dichroism (CD) spectra. Due to the presence of protonated free tetramethyl ethylenediamine (TMEDA) cations, the adjacent clusters and TMEDA cations can be connected by hydrogen-bonding interactions. The {V₄} cluster linked adjacent clusters via hydrogen bonds to form a 3D supramolecular network. The open aperture Z-scan spectra of two compounds show that molecular TPA cross-section σ of 1-L and 1-D are 1412 and 1094 GM, respectively, which illustrate that they feature decent third-order NLO properties and may have great potential applications as NLO materials.