Gamma-Herringbone Polymorph of 6,13-Bis(trimethylsilylethynyl)pentacene: A Potential Material Forenhanced Hole Mobility

The introduction of the trialkylsilylethynyl group to the acene core is known to predominantly transform the herringbone structure of pentacene to a slip-stacked packing. However, herein, the occurrence of an unforeseen polymorph of 6,13-bis(trimethylsilylethynyl)pentacene (TMS-pentacene), with an atypical gamma-herringbone packing arrangement, is reported. Intermolecular noncovalent interactions in the -herringbone polymorph are determined from Hirshfeld surface and quantum theory of atoms-in-molecules (QTAIM) analyses. Furthermore, a comparative truncated symmetry-adapted perturbation theory (SAPT(0)) energy decomposition analysis discloses the role of exchange repulsions that govern molecular packing in the gamma-herringbone polymorph. Moreover, the computationally predicted electronic coupling and anisotropic mobility reveal the possibility of enhanced hole transport (mu(h) = 3.7cm(2)V(-1)s(-1)) in the gamma-herringbone polymorph, in contrast to the reported polymorph with a hole mobility of mu(h) = 0.1cm(2)V(-1)s(-1).