Understanding Intermolecular Interactions in a Tetracene-F4TCNQ Cocrystal via Its Electron Density Distribution and Topology

High-quality single crystals of the charge transfer compound tetraceneF(4)TCNQ (1:1) were grown by physical vapor transport and characterized by IR and UV/vis spectroscopy as well as by accurate single-crystal X-ray diffraction in combination with a topological analysis of electron density distribution. The cocrystal is assembled via weak noncovalent p...p interactions. Experimental static deformation density maps demonstrate the regions of charge accumulation directed toward the areas of electron density depletion within the stacks composed of alternating donor and acceptor molecules; the energy of these interactions is estimated to be 11.3 kcal/mol per acceptor molecule. The cumulative energy of multiple side-on F...H and N...H intermolecular attractive interactions is approximately the same as the value for face-to-face interactions. The estimation of the charge transfer degree by various methods gives a value in the range 0.100.20 e.

Automated summary

High-quality single crystals of the charge transfer compound tetraceneF(4)TCNQ (1:1) were grown by physical vapor transport and characterized by various spectroscopic and crystallographic methods, revealing the interactions between molecules and the degree of charge transfer.