One-dimensional bis(dipyrrinato)zinc(II)-linked porphyrinatozinc(II) polymer: synthesis, exfoliation into single wires, and photofunctionality

Bottom-up nanomaterials are attractive as constituents of molecular-scale devices. In particular, 1D coordination nanochains based on bis(dipyrrinato)zinc(II) complexes are promising candidates for molecular photonic wires, as they can deliver photogenerated excitons along their straight chain structure efficiently. Moreover, the coordination polymers can be dispersed in organic solvents. This feature allows the preparation of a thin film on an electrode surface, which can serve as an active layer of photoelectric conversion systems. Hybridization of multiple photoactive chromophores in single-molecular materials may enhance their photophysical properties. Porphyrins and dipyrrin–metal complexes are well-studied pigments that convert the absorbed light energy into photofunctions such as photoluminescence and photoelectric conversion. Here, by expanding the design of the coordination nanowires, we present the preparation of a 1D coordination polymer bearing 2 efficient photo-absorbing chromophores: bis(dipyrrinato)zinc(II) and porphyrinatozinc(II). The bulky substituents on the porphyrin units allow the coordination polymer to be exfoliated into single-molecular wires with a height of 2.5 ± 1.0 nm and a length of 1.8 ± 0.3 μm. The coordination polymer exhibited photoluminescence and photoelectric conversion properties derived from the electronic interaction between the 2 moieties. Therefore, the design flexibility of bottom-up coordination nanochains can enrich the photofunctionality and broaden their potential applications in molecular devices.