Figure 3.

Synthesis of CBPQT ⁴⁺. Typically, the synthesis involves a two‐step procedure: 1) the reaction between para‐xylylene dibromide and an excess of 4,4′‐bipyridine, which affords para‐xylylenebis(4‐(4‐pyridyl)pyridinium bis(hexafluorophosphate) (XBPP⋅2PF ₆ ) in an almost quantitative yield after counterion exchange and 2) the reaction between XBPP⋅2PF ₆ and one equivalent of para‐xylylene dibromide, which produces CBPQT⋅4PF ₆ in a wide range of yields after counterion exchange, depending on the reaction conditions—12 % without any additive at 80 °C, 62 % in the presence of an HQ‐derived template under high pressure (12 kbar) at 25 °C, 81 % in the presence of a DN‐derived template under high pressure (12 kbar) at 25 °C and 20 % in the presence of a catalytic amount of tetrabutylammonium iodide (TBAI) at 80 °C.