An Exceptionally Close, Non-Bonded Hydrogen-Hydrogen Contact with Strong Through-Space Spin-Spin Coupling.

Condensation of 1,8,13-tris(mercaptomethyl)triptycene and tris(bromomethyl)methane yields an in,in-cyclophane with two inwardly directed methine groups. Based on X-ray analysis and DFT and MP2 calculations, the hydrogen-hydrogen non-bonded contact distance is estimated to be 1.50-1.53 Å. Furthermore, the two in-hydrogen atoms show obvious spin-spin coupling with J=2.0 Hz.