A World Beyond Hydrogen Bonds?—Chalcogen–Chalcogen Interactions Yielding Tubular Structures



It is shown that tubular structures arise in the solid state through close chalcogen–chalcogen (X⋅⋅⋅X) contacts. As examples a variety of cyclic systems containing sulfur and selenium centers is presented. Common to all of them are close contacts between the chalcogen centers of neighboring stacks giving rise to a zigzag or ladder-type arrangement. In the case of cyclic systems of ring size 24–33 the resulting tubes are able to include hydrocarbons as guest molecules. For 2,7-ditelluraocta-3,5-diyne (17) the close contacts between the tellurium centers of the acyclic C2 symmetric building blocks generate a helical arrangement in which n-hexane was included. The favored X⋅⋅⋅X contacts can be traced back to np(X)–σ*(X[BOND]C) interactions.