Crystal, Molecular and Electronic Structure of the Electron Acceptor 2,5-difluoro-7,7,8,8-Tetracyano-p-quinodimethane, 2,5-TCNQF2

Abstract

The crystal structure of the electron acceptor 2,5-difluoro-7,7,8,8-tetracyano-p-quinodimethane, 2,5-TCNQF2, has been determined by single-crystal X-ray diffraction methods. The layered crystal structure is dominated by the antiparallel coupling of cyano bond moments of symmetry-related molecules. The molecular and electronic structure (INDO approximation) of 2,5-TCNQF2 are extensively compared to that of its parent TCNQ and the perfluoro analog TCNQF4. Crystal data for 2,5-TCNQF2 are as follow: monoclinic, space group C2/m, a=10.208(4) Å, b=6.026(2) Å, c=8.836(3) Å,β=106.64(3)[ddot], V=520.8 ų. The site symmetry (2/m;C_2h) in the crystal is identical to that for the free 2,5-TCNQF2 molecule