We prepared a 9,10-dihydro-9,10-disilaanthracene (DSA) derivative 4 bearing a bulky aryl substituent, a 2,4,6-triisopropylphenyl (Tip) group, on the silicon atoms via a Wurtz-type coupling reaction between two molecules of (2-chlorophenyl)(2,4,6-triisopropylphenyl)silane ( 3) in a head-to-tail fashion. The structural determination of cis- 4 and trans- 4 was examined using 1H NMR spectroscopy and theoretical calculations. In addition, the molecular structure of cis- 4 was unambiguously determined by X-ray crystallography. The tricyclic DSA skeleton of cis- 4 adopts a folded structure with a boat-like central ring in which the rotation about the Si–Tip bond is restricted. In contrast, theoretical calculations suggest that the tricyclic DSA skeleton of trans- 4 has an almost planar structure.
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