A structural, spectroscopic and DFT theoretical comparison of the cis and trans isomers of a cyclohexasilane

We report a synthesis of the trans and cis isomers of 1,4‐di‐ tert ‐butyl‐2,2,3,3,5,5,6,6‐octamethyl‐1,4‐diphenylcyclohexasilane ( 3 ), together with the solid‐state structure of cis ‐ 3 . Both isomers were characterized using multinuclear NMR and UV spectroscopies and were compared based on these data, together with DFT calculations. Remarkably, we found that both isomers of 3 showcase redshifted UV maxima when compared with other known cyclosilanes. To explain this, the theoretical calculations show that the transitions involved in the excited states of trans ‐ 3 and cis ‐ 3 have, in addition to the expected σ conjugation component of the Si 6 ring, significant π contributions of phenyl substituents. The results presented herein show the effect of the substituent's electronic properties regarding reactivity of intermediates, reaction yield, identity, and electronic properties of novel silicon‐containing molecules.