Supramolecular Organization Based on van der Waals Forces: Syntheses and Solid State Structures of Isomeric [6.6]Cyclophanes with 2,5‐Diselenahex‐3‐yne Bridges

The ortho , meta , and para isomers 4 – 6 of [6.6]cyclophanes with 2,5‐diselenahex‐3‐yne bridges were synthesized by reacting the bis(selenocyanatomethyl)benzene derivatives 8a – 8c with the lithium salt of trimethylsilylethyne to yield 9a – 9c , deprotection of which afforded the bis(ethynylselenylmethyl)benzenes 10a – 10c . The condensation of the bis‐lithium salts of 10a – 10c with 8a – 8c yielded the target compounds 4 – 6 . X‐ray investigations on single crystals of 4 – 6 revealed intermolecular Se ··· Se interactions which contribute significantly to the solid‐state structures of these species. In the case of the orthocyclophane 4 , we found short distances between one Se–C≡C–Se unit of each molecule leading to a linear chain of orthocyclophane rings. In the metacyclophane, 5 , the rings adopt a chair conformation and are piled on top of each other. The resulting molecular channels are connected with each other by intermolecular Se ··· Se interactions. For 6 also a chair conformation of the [6.6]paracyclophane unit was encountered. In the solid state the rings of 6 are connected by intermolecular Se ··· Se bridges.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)