Synthesis and properties of selenium containing dmit-type complexes

Four selenium containing dmit-type ligands (dmit = 1,3-dithiole-2-thione-4, 5-dithiolate) possessing 1,3-diselenole substructure, namely dmist (1,3-diselenole-2-thione-4,5-dithiolal:e), dsist (1.3-disclenole-2-thionc-4,5- disclcnolatc), dmis (1,3-disclcnolc-2-selone-4,5-dithiolate), and dsis (1,3-diselenole-2-selone-4,5-disclcnolatc), and their nickel complexes were synthesized and characterized. The synthesis of the ligands involved lithiation reaction of 1,3-diselenole-2-selone as a key step followed by introduction of additional chalcogen atoms. The molecular structures of (n-Bu ₄N)[Ni(dmist)₂], (n-Bu₄N)[Ni(dsist) ₂], and (n-Bu₄N)[Ni(dsis)₂] were investigated by means of X-ray analyses, and a systematic enlargement of the anion size with the number of the introduced selenium atoms was revealed.