Optical Probes of Interlamellar Redox Chemistry: Intercalation of the Creutz-Taube Complex into Hydrogen Uranyl Phosphate

摘要

Hydrogen uranyl phosphate (HUP) can be intercalated by the Creutz-Taube (C-T) complex, Ru(NH3)52(mu-pyrazine) 5+, to yield hydrated, partially-substituted lamellar solids, H(C-T)UP, of approximate composition H(1-5x)(C-T)xUO2PO4 (0.001< x <0.01). The more crystalline samples exhibited an X ray powder pattern similar to that of HUP: the structure can be indexed in tetragonal symmetry and possesses an interlamellar spacing of approx. 8.69 A. The absorption spectrum of H(C-T)UP appears to be a simple superposition of bands due to the UO2(2+) moiety and the C-T complex. Photoluminescence (PL) of H(C-T)UP is quenched relative to HUP; PL decay curves are nonexponential and span a shorter time domain relative to HUP. Exposure of H(C-T)UP to br2 vapor causes the purple solid to become yellow. The spectral changes are consistent with redox chemistry wherein the intercalated C-T complex undergoes oxidation. For most samples examined, the PL decay times were enhanced upon oxidation. Keywords: Cruetz Taube complex; Intercalation; Hydrogen uranyl phosphate, Phosphates.