Solution and Solid State Studies of Tetrafluoro-7,7,8,8-Tetracyano-p-Quinodimethane, TCNQF4. Evidence for Long-Range Amphoteric Intermolecular Interactions and Low-Dimensionality in the Solid State Structure

Abstract Solution and solid state studies of TCNQF4 are reported. The electron affinity of TCNQF4 has been derived from spectral observations of the visible-near IR charge-transfer band for the pyrene complex and compared to that derived from the half-wave potentials used to characterize its reactivity in solution. It is demonstrated that the series, TCNQ, TCNQF to TCNQF4 shows a monotonic increase in reactivity with increasing fluorine substitution. Crystals of TCNQF4, grown from acetonitrile, are orthorhombic; space group Pbca, with the following crystal data: a = 14.678(7)A, b = 9.337(5)A, c = 8.174(2)A, V = 1120.0(6)A3, Z = 4 [based on a molecular weight for C12N4F4 = 276.22], Dmeasd = 1.65(1) g cm−3, Dcalcd = 1.64 g cm−3. Full matrix least-squares refinement (including anisotropic thermal parameters for all atoms) using 1763 counter-collected Fa's led to a final R value of 0.067 and a final weighted R value of 0.036. The observed molecular geometry of TCNQF4 is compared to that of its parent molecule...