Polarized electronic spectra for the crystals of three compounds, potassium tetrabromoplatinate(II) dihydrate, tetraethylammonium hexabromodiplatinate(II), and tetra-μ-glycine-dimolybdenum (II) sulfate tetrahydrate

Thesis/Dissertation · Wed Jun 01 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/7303597· OSTI ID:7303597

Peters, Timothy Joseph ^[1]

---

1. Iowa State Univ., Ames, IA (United States)

The polarized absorption spectra for K₂PtBr₄ . 2H₂O, (N(C₂H₅)₄)₂PtBr₆, and Mo₂(O₂CCH₂NH₃)₄(SO₄)₂ . 4H₂O have been recorded at 300 and 15/sup 0/K. In K₂PtBr₄ . 2H₂O the bands at 24,000 and 27,000 cm^-1 in both a- and b-polarizations appear to be vibronically induced. The energy spacing of the vibrational structure was noted to be somewhat higher at 180 cm^-1 than for the analogous structure of K₂PtBr₄. The presence of a Pt₂Br₆^-2 impurity gave rise to red sections, which evidently were due to the electron transfer, Pt(IV)/reverse arrow/Pt(II), occurring in c-polarization. Very weak spin-forbidden bands were observable in all three polarizations below 23,500 cm^-1. In the crystal spectra of (N(C₂H₅)₄)₂Pt₂Br₆ the transitions were defined with respect to the three molecular axes of the Pt₂Br₆^-2 ion. Excited states were assigned under the D₂sub h/ point group symmetry of the ion. The delocalization of the d electrons gave rise to strongly enhanced intensities for both spin-forbidden and spin-allowed d/reverse arrow/d transitions. The M/reverse arrow/L charge-transfer transitions occur at lower energies in the case of Pt₂Br₆^-2 than in PtBr₄^-2. These charge transfer transitions were found from the polarizations to originate from the terminal bromides. The crystal spectra of Mo₂(O₂CCH₂NH₃)₄(SO₄)₂ . 4H₂O were recorded through the region 20,000 - 25,000 cm^-1. The spectra at 15K revealed the vibrational structure in the two recorded polarizations. The electronic transition observed in these spectra was forbidden under the local symmetry of D_4h.

• Research Organization: Ames Lab., Ames, IA (United States)
• Sponsoring Organization: US Energy Research and Development Administration (ERDA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7303597
• Report Number(s): IS-T--764
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTRA
AMINES
AMMONIUM COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
COMPLEXES
CRYSTALS
HALIDES
HALOGEN COMPOUNDS
HYDRATES
MOLYBDENUM COMPLEXES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLATINUM COMPLEXES
QUATERNARY COMPOUNDS
SPECTRA
SULFATES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPLEXES