Synthesis of copper-selenium complex

Abstract

This research proposed to synthesize metal-organic frameworks (MOFs) from selenium-containing ligands and to study crystal structures of synthesized MOFs. MOFs can be designed in many ways, depended on types of metal center and linkage ligands. Selenium-containing organic molecules were rarely found, but they were a good choice for medical field. In this work, we tried to synthesize selenium-containing ligands from Schiff base reaction and Friedel-Craft acylation. However, the reactions were unsuccessful. In the other hand, we synthesized a coordination compound from commercial ligands, selenite ion from sodium selenite and seleno-L-cystine, which is amino acid. The experiment results showed that dark blue block shape crystals were obtained from the reaction of copper(II) acetate, selenite ion, and 4,4'-bipyridine using hydrothermal method at 170 °C. The crystal was determined using single crystal X-ray diffraction technique. The unit cell of crystal was cubic with space group of P2₁3. The structure was grown to be a three-dimensional framework. When compare to the literature, the crystal structure was different. Coppers were in distorted square-pyramidal geometry because this work used copper(II) acetate, which is in square-pyramidal geometry; however, other's work used copper salts in octahedral geometry. In the part of seleno-L-cystine complex synthesis, which was the mixing at room temperature, the blue solid that was similar to clays and no crystallinity. The product was characterized by FTIR and found that the characteristic peaks of Cu-O stretching at 685 cm⁻¹ was disappeared; nevertheless, the limitation of equipment was a problem for collecting the data at lower than 650 cm⁻¹.