Complex Formation Between Pyrene and the Nucleotides Gmp, Cmp, TMP and Amp

Abstract— Pyrene has been found to form ground and excited electronic state complexes of 1:1 stoichi‐ometry with GMP, CMP, TMP and AMP. The values of their ground state association constants are 45 M ‐1 , 13 M ‐1 , 14 M ‐1 , and 52 M ‐1 respectively. The fluorescence of pyrene is strongly quenched by GMP, CMP, and TMP but only slightly by AMP. Fluorescence quenching analysis has yielded the values 87 M ‐1 , 73 M ‐1 , and 154 M ‐1 for the excited state association constants with GMP, CMP, and TMP, respectively. The corresponding values for the excited state second‐order rate constant for complex formation are: 3.3 times 10 9 M ‐1 s ‐1 4.1 times 10 9 M ‐1 s ‐1 , and 4.0 times 10 9 M ‐1 s ‐1 . The probabilities of complex formation per collision between an excited pyrene molecule and a nucleotide are: 0.52, 0.64, and 0.63. The values for the excited state rate constant for dissociation of the complex are: 3.8 times 10 7 s ‐1 5.6 times 10 7 s ‐1 , and 2.6 times 10 7 s ‐1 . The possibility is discussed that partial transfer of charge from pyrene to nucleotide may be playing a role in the complex formation process.