Abstract
We report the design and synthesis of ferrocene and triphenylamine substituted D-pi-A-pi-D and D-pi-A-pi-A-pi-D type of symmetrical pyrazabole monomers (3 and 5) and dimers (6 and 7). Their optical, thermal, electrochemical and computational properties were investigated. The electronic absorption spectra of pyrazaboles 3-7 exhibit absorption bands in UV region. The TGA study reveals that pyrazaboles 3-7 show good thermal stability and pyrazabole monomers are thermally more stable as compared to pyrazabole dimers. The electrochemical studies show that pyrazaboles 3-7 exhibits one reversible oxidation and two reduction waves. The theoretical investigation shows that the triphenylamine substituted pyrazaboles (5 and 7) exhibit low HOMO-LUMO gap values compared to ferrocenyl pyrazaboles (3 and 6).