Crystal structure and physical properties of 1,3,6,8-tetrakis(ethylthio)pyrene-Qmnt complex

The 1:1 complex of 1,3,6,8-tetrakis(ehylthio)pyrene (TEPY) and 5,10-dihydro-5,10-dioxobenzo[1,2-b:4,5-b′]bis[1,4]dithiin-2,3,7,8-tetracarbonitrile (Qmnt) has been isolated as needle crystals and its crystal structure determined. The triclinic (P1, Z=1) unit cell data are as follows: a=8.213(3) b=9.542(2), c=12.240(2)Å, α=74.01(1), β=83.64(2), γ=76.94(3)•, V=897.0(4) Å3, Dcal=1.531 g cm−3, R=0.045 for 2348 observed reflections (I>2σ (I)). The centrosymmetric π-donor and π-acceptor, situated with their centers of symmetry at (12, 0,0) and (0,0,0) respectively, are stacking alternately along the a axis. The solid-state IR spectrum, as well as the dilute-solution UV-VIS spectrum, of the complex is essentially a superposition of the spectra of the parent compounds, indicating that it is a neutral charge-transfer complex. The room-temperature conductivity is low (5.2×10−6 S cm−1, measured on single crystal along the needle axis), as expected for a neutral mixed-stack complex.