Publications [#232118] of Stephen L Craig

Journal Articles

  1. Wang, J; Kouznetsova, TB; Kean, ZS; Fan, L; Mar, BD; Martínez, TJ; Craig, SL, "A remote stereochemical lever arm effect in polymer mechanochemistry.", Journal of the American Chemical SocietyOctober,, 2014, 136(43), 15162-15165 [doi].
    (last updated on 2024/03/28)

    Abstract:
    Molecular mechanisms by which to increase the activity of a mechanophore might provide access to new chemical reactions and enhanced stress-responsive behavior in mechanochemically active polymeric materials. Here, single-molecule force spectroscopy reveals that the force-induced acceleration of the electrocyclic ring opening of gem-dichlorocyclopropanes (gDCC) is sensitive to the stereochemistry of an α-alkene substituent on the gDCC. On the ∼0.1 s time scale of the experiment, the force required to open the E-alkene-substituted gDCC was found to be 0.4 nN lower than that required in the corresponding Z-alkene isomer, despite the effectively identical force-free reactivities of the two isomers and the distance between the stereochemical permutation and the scissile bond of the mechanophore. Fitting the experimental data with a cusp model provides force-free activation lengths of 1.67 ± 0.05 and 1.20 ± 0.05 Å for the E and Z isomers, respectively, as compared to 1.65 and 1.24 Å derived from computational modeling.