Highly conductive metallophthalocyanine assemblies. Structure, charge transport, and anisotropy in the metal-free molecular metal H2(Pc)I

Abstract

That a metal ion is not required for high electrical conductivity is unequivocally demonstrated by structural, charge transport, optical, and magnetic characterization of the simplest phthalocyanine “molecular metal” H₂(Pc)I. The crystal structure consists of staggered H₂(Pc)^+0.33 units stacked at 3.251(3) Å intervals and parallel chains of I⁻₃ counterions. At 300 K, $\text{σ}{}_{\mathrm{\Vert }}\text{= 700 Ω}{}^{\mathrm{-1}}\text{cm}{}^{\mathrm{-1}}$ and $\text{σ}{}_{\mathrm{\Vert }}\text{σ⊥ > 500}$. At 15 K, σ_∼ reaches a maximum of ca. 4000 Ω⁻¹ cm⁻¹ and falls only to ca. 3500 Ω^−1‖ cm⁻¹ at 1.5 K. Analysis of single crystal polarized specular reflectance data (ir to uv) yields ω_p = 6360(30) cm⁻¹ and a tight-binding bandwidth of 1.3(1) eV. The magnetic susceptibility is Pauli-like (X_S = 2.21(5) × 10⁻⁴ emu mol⁻¹) except for a small, sample dependent Curie component.