The crystal structure of the radical anion salt of naphthalene tetracarboxylic dianhydride (NTDA) and 5,6-dihydro-4a, 6a-phenanthrolene dionium (DPD): a new charge transfer complex

Abstract

Abstract The crystal structure of the title compound was determined at room temperature. The crystals are triclinic, space group P[unk] with a = 8.935(1) Å, b = 12.785(2) Å, c = 15.995(2) Å, α = 112.38(2)°, β = 92.03(1)° and γ = 93.68(1)°. There are 5 NTDA and 2 DPD molecules in the unit cell. One NTDA molecule is on an inversion centre. The structure was refined to R = 0.038 for 5057 observed reflections and 666 variables. The correlation between the chemical equivalent bond lengths is generally very good, thus confirming the carbonyl distance (mean value = 1.206 Å) which is significantly greater than in the lattice consisting only of NTDA molecules. The crystal is built of stacks of NTDA molecules along [1 0 1] with three different overlapping modes. The interplanar spacings are 3.206 Å, 3.188 – 3.366 Å and 3.194 – 3.288 Å respectively. The DPD molecule is surrounded by 18 oxygen atoms from six different NTDA molecules.