New conductive polymeric materials: Cofacial assembly of mixed valent metallomacrocycles

This paper reports on an approach to control molecular stacking interactions in low-dimensional mixed valence materials by locking partially oxidized metallomacrocycles together in a cofacial orientation. Iodine doping of the face-to-face linked oligomers [M(Pc)O]_n (M = Si, Ge, Sn; Pc = phthalocyaninato) produces electrically conductive polymers {[M(Pc)O]I_xn with a wide range of x stoichiometries. Resonance Raman spectroscopy indicates that the iodine has oxidized the polymer chain. Polymer structure has been studied by X-ray powder diffraction, and it is possible to estimate interplanar spacings. Halogen doping of the [M(Pc)O]_n materials is accompanied by electrical conductivity increases as large 10⁷ (ohm cm)^?1; the general trend is $\text{σ}{}_{\mathrm{<mtext>Si</mtext>}}\text{? σ}{}_{\mathrm{<mtext>Ge</mtext>}}\text{> σ}{}_{\mathrm{<mtext>Sn</mtext>}}$. Variable temperature conductivity and magnetic susceptibility data are reported.