Electronic Structure Manipulation of (Benzothiazole)zinc Complexes: Synthesis, Optical and Electrochemical Studies of 5-Substituted Derivatives

The electronic properties of bis[2-(2-hydroxyphenyl)benzothiazolato]zinc(II) complexes were tuned by attachment of electron-withdrawing and -donating aryl groups through the Suzuki-Miyaura coupling reaction. Optimization studies of the borylation reaction and Suzuki coupling of protected benzothiazoles were performed to maximize the yields of the target compounds. The absorption, emission, and electro-chemical properties of the newly synthesized complexes were found to correlate to the electronic nature of the attached aryl group. Whereas the LUMO levels are less dependent on the substituents, the HOMO levels are very sensitive to the nature of the substituent, thus providing an array of organometallic complexes with gradual changes in redox potentials.