• Dr. Shamshad Ahmad Khan

Biphenyl is a C-C bridged benzene rings which resonate as a whole. It is symmetric molecule and its resonance structures are defined through the Kekule structures of benzene rings. In the present work, UV-Vis spectroscopic studies of the charge-transfer complexes of biphenyl and its derivatives. Spectral data and the thermodynamic functions ΔG0, ΔH0 and ΔS0 for the complex formation have been determined. As the solutions of the investigated electron donor acceptor (EDA) complexes were dilute, these complexes did not exhibit their own colours. Furthermore, C-tmethylbz11, C-methylbz41, C-4-OHBP, C-BP, C-BrBP and C-4,4′-DIOHBP have absorption maxima similar to the absorption maximum of 4,4′-DNBP. It may be possible that the complexes are dissociated to their low pure compounds in solution. In this case the donor components are not visible because of their low concentrations to the complexes. UV, being a concentration sensitive method, failed to detect the components with low contribution in the complex. The C-C tmethylbz11 was the only complex where the donor component is equivalent with 4,4′-DNBP and as such it was expected to observe two absorption maxima, one belonging to tmethylbz and one to 4,4′-DNBP. Only C-BZ shows a significant 5 nm difference from the original 4,4′-DNBP absorption which may be seen as an interaction, H-bonding between the NO2 and NH2 functional groups is possible. The H-bonding will necessitate the partial shift of more electrons to the oxygen atoms in the nitro groups thereby reducing the double bond character of the 4,4′-DNBP, and as a result absorption maximum of the 4,4′-DNBP components of the C-BZ will appear at a shorter wavelength

UV-Visible Spectroscopic Studies of Charge- Transfer Complexes

"UV-Visible Spectroscopic Studies of Charge- Transfer Complexes", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.1, Issue 5, page no.140-146, October-2014, Available :http://www.jetir.org/papers/JETIR1701424.pdf

"UV-Visible Spectroscopic Studies of Charge- Transfer Complexes", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.1, Issue 5, page no. pp140-146, October-2014, Available at : http://www.jetir.org/papers/JETIR1701424.pdf