Star shaped ferrocenyl truxenes: synthesis, structure and properties

This article reports the design and synthesis of star shaped, C3-symmetric ferrocenyl substituted truxenes by the Pd-catalyzed Sonogashira cross-coupling and cycloaddition reaction. The single photon absorption and electrochemical properties indicate significant electronic interaction between ferrocene and truxene core. The bathochromic shift in the absorption spectra of truxenes 4a-4c and 5a is a function of enhanced conjugation. The incorporation of tetracyanoethylene (TCNE) results in a strong charge transfer band in truxene 5a. The single crystal structure of truxene 4a is presented, which shows interesting supramolecular interactions.