Confinement of single polysilane chains in coordination nanospaces.

ABSTRACT

Understanding the intrinsic properties of single conducting polymer chains is of interest, largely for their applications in molecular devices. In this study, we report the accommodation of single polysilane chains with hole-transporting ability in porous coordination polymers (PCPs), [Al(OH)(L)]n (1a; L = 2,6-naphthalenedicarboxylate, channel size = 8.5 × 8.5 Å(2), 1b; L = 4,4'-biphenyldicarboxylate, channel size = 11.1 × 11.1 Å(2)). Interestingly, the isolation of single polysilane chains increased the values of carrier mobility in comparison with that in the bulk state due to the elimination of the slow interchain hole hopping. Moreover, even when the chains are isolated one another, the main chain conformation of polysilane could be controlled by changing the pore environment of PCPs, as evidenced by Raman spectroscopy, solid-state NMR measurements, and molecular dynamics simulation. Hence, we succeeded in varying the conducting property of single polysilane chains. Additionally, polysilanes have a drawback, photodegradation under ultraviolet light, which should be overcome for the application of polysilanes. It is noteworthy that the accommodation of polysilane in the nanopores did not exhibit photodegradation. These results highlight that PCP-polysilane hybrids are promising candidates for further use in the field of molecular electronics.