Expanded segments of three-dimensional carbonaceous nets with chirality: synthesis and structures

As a strongly isotropic net that fills three-dimensional space, a chiral net known as (10,3)-<i>a</i> was recently rediscovered as a diamond twin (pollux) composed of sp²-hybridized carbon atoms. Although the trigonal planar structure of phenine has allowed for the synthesis of the primal cage molecule phenine polluxene, the expansion of polluxene provides further synthetic challenges as has been the case with polymantanes, including congressane. This work exploited three-component covalent assembly as a cage-forming reaction and succeeded in constructing a two-story structure of phenine dipolluxene with the homohelical sextuple helix of (10,3)-<i>a</i> net. Unexpectedly, the dipolluxene structure tolerated dimeric entanglements, resulting in an interpenetrated (10,3)-<i>a</i> net with a homohelical duodecuple helix.