Synthesis, structure, photophysical, and electrochemical properties of donor-acceptor ferrocenyl derivatives

A series of donor-acceptor compounds 2-6 have been synthesized, via Knoevenagel condensation reaction (using conventional method, as well as microwave method). The ferrocene unit acts as a donor, conjugated phenyl-acetylene linker act as a pi-electron relay unit, and malononitrile, cyanoacetic acid, and indanone groups act as acceptor. The electronic absorption spectra displayed a broad intramolecular charge transfer (CT) band in the visible region (450-650 nm). The electrochemical studies suggest considerable donor acceptor interaction. The single crystal X-ray structure of 2, and 3 are reported, the structure reveals that 2 is nearly planar compared to 3. The supramolecular structure of 2 exhibits intramolecular C-H-pi, and C-H-N interaction, which leads to formation of 2D network, whereas compound 3 shows head to tail dimer formation through C-H-pi, and pi-pi interaction. (C) 2012 Elsevier Ltd. All rights reserved.