Charge transfer interactions between nucleic acid bases and strong acceptors

✍ Scribed by G. G. Sheina; E. D. Radchenko; S. A. Egupov; Yu. P. Blagoy; V. M. Orlov

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 359 KB
• Volume: 16
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.560160218

✦ Synopsis

Abstract

The regularities of the donor‐acceptor interaction of nucleic acid bases and some of their derivatives with the strong acceptor 7,7,8,8‐tetracyanoquinodimethane (TCNQ) in thin amorphous films at 77 K were studied using UV and visible spectroscopy. Purine and pyrimidine bases are shown to form charge transfer TCNQ complexes whose band energies h__ν~ct~ = I~p~ − E~A~ − (H* − H^0^) are linearly dependent of the donor ionization potential I~p~. Calculated differences between the interaction energies of uncharged molecules and ion radicals, Δ__E ≈ 3.0 eV, are in good agreement with experimental variations of the complex dissociation energies in the ground and excited states, (H* − H^0^) = 2.73 eV. Annealing of the films of complexes containing cytosine, 1‐methylcytosine, uracil, and caffeine leads to ordering of their structure and the formation of ion radical salts.