Highlighting Intermolecular Contacts and Spectral Properties in a New Organic Donor–Acceptor Complex: Synthesis, Structure and Infrared Spectroscopy of MT-TCNB (MT = bis(methylenedithio)tetrathiafulvalene)

Herein we present the synthesis, single crystal X-ray structure and spectroscopic properties for the 1:1 donor–acceptor complex MT-TCNB. The complex crystallizes in the triclinic space groupv P 1 ¯ with a = 7.4625(11) Å, b = 8.0080(12) Å, c = 9.8586(15) Å, α = 97.397(7)°, β = 102.611(7)°, and γ = 114.077(8)°. Bond distances for the central C=C bond and four ancillary C–S bonds in BMDT-TTF (MT) as well as the cyanide groups in TCNB were compared to those in their free analogues and suggest that both constituent molecules within the complex are neutral. Additionally, infrared (IR) spectroscopy measurements were conducted in order to assess the evolution of the cyanide and C–H vibrational frequencies for the TCNB acceptor in both its free and complexed states. Like the structural data, the latter also supports the conclusion that the complex’s constituent molecules remained neutral. Graphical Abstract Herein we present the structure and infrared spectroscopic properties of the 1:1 donor–acceptor complex MT-TCNB, which combines the TTF derivative BMDT-TTF (BMDT-TTF = bis(methylenedithio)tetrathiafulvalene or MT) with the organocyanide acceptor TCNB (TCNB = 1,2,4,5-tetracyanobenzene).