1,1,2,2-Tetracyanocyclopropane (TCCP) as supramolecular synthon

The 1,1,2,2-tetracyanocyclopropane (TCCP) unit presents a synthetically accessible and versatile synthon that can interact with lone-pair or pi-electrons by 'non-covalent carbon bonding'. Complexes of TCCP with common small molecules, anions, aromatics like fullerenes, amino acids and nucleobases were computed at the DFT BP86-D3/def2-TZVP level of theory. Binding energies vary between about -10 kcal mol(-1) for neutral guests and -15 to -50 kcal mol(-1) for anionic species. This is comparable to strong and very strong hydrogen bonding respectively. Thus, in addition to synthons that contain polarized hydrogen or halogen atoms, TCCP presents a new supramolecular synthon that awaits experimental exploitation.