Spectroscopic study of the octachloroditechnetate(3-) ion

Preparation of Octabromoditechnetate(III,II), [Tc2Br8]3- and the Vibronic Structure of the δ → δ* Transition

“…For K 3 [TC 2 C1 8 ] • 2 H 2 0 the spin-and orbitally-allowed Ö -*• Ö* transition has been assigned in good agreement with SCF-X a -SW calculations to a band originating in the near infrared region at 5900 cm -1 [2]. The vibrational progression on this transition is better resolved in the Cs-salt [3] and in the tetra(2-oxopyridinato)chloroditechnetate TC 2 (OC 5 H 4 N) 4 C1 [4].…”

“…The well resolved vibrational progression of the band between 1100 and 2000 nm measured on powdered Cs 3 [Tc 2 Br 8 ] in a CsBr disk at 6 K is shown in Figure 1. At room temperature we observe two hot bands at 1767 and 1874 nm as shown in Figure 2.…”

“…The resulting brown powder is dissolved in 20 ml dichloromethane, and under admittance of air a stream of hydrogen chloride is passed through for about 15-20 minutes until the colour turns from brown to green or at least greenish-brown. The resulting solution is shaken under repeated exposure to air, admixed dropwise with diethylether until beginning turbidity and brought to crystallization of green (TBA) 2 [TC 2 C1 8 ] at -30°C.…”

“…Yields depend strongly on the appropriate balance of the necessary exposure to air and amount up to 85%; excessive application of air increases formation of undesired yellow (TBA) 2 …”

Single-crystal polarized electronic spectra of the compounds tetra-[Greek letter mu]-acetatodimolybdenum(II), tetrakis-[Greek letter mu]-(trifluoroacetato)-dimolybdenum(II), potassium-diaquo-tetra-[Greek letter mu]-sulfatodiplatinum(III), and the X-ray diffraction crystal structure of tetra-[Greek letter mu]-acetatodimolybdenum(II)·potassium chloride

“…Crystals of provided the first polarized spectra of a carboxylase compound; and they are especially important, because crystals of this compound are tetragonal (18). The metal-metal axis is aligned with the c axis, so crystal spectra provided directly the molecular polarizations.…”