Japanese to English Science Chemistry; Chem Sci/Eng

単結合部に介在物がない, where "inclusion" seems likely(?) to be incorrect.

Describing aromatic rings, and trying to distinguish between a direct single bond as in biphenyl/terphenyl/etc. and a compound containing phenyl rings linked by CONH or similar. I'm not sure how to translate 介在物. Dictionary translation is "inclusion", but online definitions seem to indicate that means something else entirely. Could it be said that biphenyl and the like have "no intervening linkage (in the single bond? (region?))" between phenyl rings, to distinguish them from the compounds that do?

Please note that I have been instructed that "not one single character (of the Japanese source) is to be interfered with", and this is for a response to a final office action in patent prosecution.