Raman spectroscopic studies on palladium and platinum hydrido complexes

Raman spectra of platinum metal hydrido complexes, Na2PtH4 (I4/mmm), K2PtH4 , K2PtD4, Rb2PtH4, Rb2PtD4, Rb2PdD4 (F m(3) over bar m) and K3PtH5 (P4/mbm) , are presented and discussed with respect to the influence of the differen t strengths of Pt-H and Pd-H bonds and of the relative volume of the reduce d (per formula unit) unit cells. The 'antisymmetric' MD (M = Pt, Pd) stretc hing mode (species B-1g of free, square MX4 units) decreases from 1436 to 1 291 cm(-1) on going from K2PtD4 to Rb2PdD4. Likewise, the PtH stretch of Na 2PtH4 at 2026 cm(-1) decreases to 2001 cm(-1) for K2PtH4 but increases to 2 039 cm-l for K3PtH5. The totally symmetric MH stretches (A(1g)), which are of lower intensity, are shifted by about 50 cm(-1) to higher wavenumbers co mpared with the asymmetric stretches. The results of a group theoretical tr eatment of the respective site group and unit-cell group modes are given. C opyright (C) 1999 John Wiley & Sons, Ltd.