Chemical stability and characterization of rhodium-diisocyanide coordination polymers.
Poly-[Rh(1,4-phenylene diisocyanide)+4/2(Cl)-] has a two-dimensional template structure, where Rh atoms are bonded by the -conjugated 1,4-phenylene diisocyanide (pdi) ligands in the x-y plane and through overlapping dz orbitals in the z direction. The more conductive metallic bonds in the z direction create anisotropy in the electrical conductivity. The anisotropy and unique geometry of poly-[Rh(pdi)+4/2(Cl)-] make it a useful test bed for examining the relationship between electrical properties and chemical stability in metal-isocyanide molecular wire systems. The bulk powder of poly-[Rh(pdi)+4/2(Cl)-] is estimated to have a room-temperature bulk conductivity of 3.4 x 10(-11) S x cm(-1), an electrical activation energy of 0.9 eV, and a dielectric constant of 7.5. In this paper, impedance spectroscopy and X-ray powder diffraction were used to show the dependence of the electrical conductivity on the metal-metal bonding of pressed bulk powders of poly-[Rh(pdi)+4/2(Cl)-]. Thermo-gravimetric analysis and X-ray photoelectron spectroscopy were used to demonstrate air sensitivity in the polymer and elucidate the mechanism of oxidative degradation.
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
Cantwell G
CG
Carson
Rosario A
RA
Gerhardt
Rina
R
Tannenbaum