Proton Conductivities of Stepwise Protonated Imidazole‐Fused Tetraphenylene Derivatives

The control of crystal structure and proton conductivity was evaluated by stepwise protonation of tetraphenylene molecules ( ImTP ) containing a imidazole group. By controlling the degree of protonation from neutral ImTP to H 1 ImTP⁺ , H 2 ImTP 2 ⁺ , and H 4 ImTP⁴⁺ , we demonstrated that the balance between intermolecular hydrogen bonding and electrostatic interactions affects structural stability and proton conductivity. X‐ray diffraction analysis revealed that neutral ImTP forms a 2D hydrogen bond network, while H 1 ImTP⁺ exhibits enhanced structural stability due to N─H⁺···Cl − electrostatic interactions. H 2 ImTP 2 ⁺ forms a 3D network, and H 4 ImTP⁴⁺ becomes amorphous. Under 40% relative humidity conditions, these compounds adsorb H 2 O to form proton conduction pathways, exhibiting conductivities of 3.20 × 10 − 7 , 3.38 × 10 − 6 , 1.35 × 10 − 6 , and 6.20 × 10 − 6 S cm − 1 at ∼363 K for n = 0, 1, 2, and 4 of H n ImTP n ⁺ Cl − n system, respectively. In particular, H 1 ImTP⁺ exhibits an optimal balance between hydrogen bonding and electrostatic interactions, resulting in high structural stability, reversible H 2 O adsorption, and proton conductivity.