To obtain coordination polymers with nonlinear optical (NLO) activity, the lactic acid derivative (R) -5- (1-carboxyethoxy) isophthalic acid, or (R) -H3cia, was selected as the chiral ligand. Through a solvothermal reaction with Cd2+ in the presence of pyrazine (pyr), the chiral complex polytetraaquabis[μ- (R) -5- (1-carboxylatoethoxy) isophthalato (μ-pyrazine) tricadmium (II) ], Cd3 (C11H7O7) 2 (C4H4N2) (H2O) 4n or Cd3{ (R) -cia2 (pyr) (H2O) 4n (abbreviated as HU32-R), was synthesized successfully. Single-crystal X-ray diffraction analysis reveals that HU32-R crystallizes in the monoclinic space group I2 and features a three-dimensional framework. The complex exhibits good phase purity and certain water stability. Solid-state circular dichroism (CD) spectroscopy confirms its macroscopic chirality. Fluorescence spectroscopy shows an emission peak at 487 nm upon excitation at 365 nm. Furthermore, second-harmonic generation (SHG) measurements indicate that HU32-R possesses significant second-order NLO activity, with an intensity approximately 0. 72 times that of potassium dihydrogen phosphate (KDP).
Yin et al. (Fri,) studied this question.