Spontaneous Assembly of 63 Topological Metal-Organic Nanotubes with Distinct Asymmetric Subunits for the Construction of Hydrophitic Intertube Channels Encapsulating Rare Helical Water-Chains

The hydrothermal reaction of cadmium nitrate hydrate (Cd(NO3)(2)center dot 4H(2)O) with p-terphenyl-type 4,4'-(1,4-phenylene)bis(2,6-dimethyl-3,5-pyridinedicarboxylic acid) (H4L), and phenanthroline (phen) in the presence of triethylamine leads to a three-dimensional supramolecular aggregate {[Cd-3(phen)(3)(HL)(2)(H2O)(2)]center dot 4.25H(2)O}. (1). In 1, the T-type second building units construct independent one-dimensional (I-D) metal-organic nanotubes (MONTs) with 6(3) topology containing distinct axially asymmetric subunits [R-Cd-3(HL) and S-Cd-3(HL)]. The adjacent RR-Cd-5(HL)(2) supersubunits form a hydrophilic intertube chiral channel (I), and the SS-Cd-5(HL)2 supersubunits generate another type of hydrophilic intertube chiral channel (II). These two types of chiral channels encapsulate two corresponding types of helical water-chains with three pseudo screw axes, exhibiting a novel chirality transformation and transfer, namely, R-Cd-3(HL) -> RR-Cd-5(HL)(2) -> chiral channel (I) - left-handed (M) water-helix, and S-Cd-3(HL) - SS-Cd-5(HL)(2) - chiral channel (II) - right-handed (P) water-helix. Photoluminescence and nitrogen adsorption behavior of 1 have been examined.