Association activation energies (Eass) of a series of TFOs, 5′-(TC)4Tn-3′, where n = 0, 1, 2, 3, 4, 6, 8; the length in base triplets is also given. The measures were performed in a 10 mM sodium cacodylate buffer (pH 6.0), 100 mM NaCl and 10 mM MgCl2. The coefficients of linear regression for the calculated Eass were in the range 0.97–0.99.