Host–Guest Chemistry of 1D Suprachannels and Dihalomethane Molecules: Metallacyclodimeric Ensembles Consisting of Zinc(II)-2,7-bis(nicotinoyloxy)naphthalene Complexes

Self-assembly of ZnX2 (X = Cl, Br, and I) with 2,7-bis­(nicotinoyl­oxy)­naphthalene (L) as a hemicircular bidentate ligand containing a chromophore moiety yields a systematic metallacyclodimeric unit, [ZnX2(L)]2. These basic skeletons constitute, via interdigitated π···π interactions, a unique columnar ensemble forming a suprachannel. This can then be employed as an unusual “diiodomethane within the suprachannel” host–guest system, CH2I2@​[ZnX2(L)]2. Specifically, the suprachannel significantly stabilizes the CH2I2 molecules in the order [ZnI2(L)]2 > [ZnBr2(L)]2 > [ZnCl2(L)]2. This suprachannel has significant halogen effects on the photoluminescence (PL), thermal properties, and host–guest inclusion.