Intercalation of Re(phen)(CO)3Cl into zirconium phosphate: a water insoluble inorganic complex immobilized in a highly polar rigid matrix

Abstract

The intercalation of fac-tricarbonylchloro-1,10-phenanthrolinerhenium(I) (Re(phen)(CO)₃Cl) within zirconium phosphate (ZrP) has been achieved using a hydrated ZrP phase that possesses six water molecules per formula unit. This intercalation occurs only at high solution molar ratios (Re : ZrP, 3 : 1) and is characterized by the emergence of a new phase in the X-ray powder diffraction (XRPD) pattern with an interlayer distance of 15.6 Å. The XRPD patterns show a decrease in the crystallinity upon intercalation of the inorganic complex. The MLCT absorption bands of Re(phen)(CO)₃Cl-containing ZrP materials are red shifted in comparison with the complex in acetonitrile whilst the luminescence spectra at different loading levels are blue shifted up to 30 nm in comparison with the complex in acetonitrile. This blue shift is consistent with the rigidochromic effect. The luminescence lifetime of Re(phen)(CO)₃Cl within ZrP was increased in comparison with its lifetime in acetonitrile solution but is shorter than that of Re(phen)(CO)₃Cl in frozen glass and polyesther resins. To our knowledge, this is the first example of a water insoluble metal complex intercalated within the layers of ZrP, which opens up new possibilities in the intercalation chemistry of this lamellar material and in the study of host–guest interactions.