The electronic spectra of the hexafluoro complexes of the second and third transition series

Soft diphosphine and diarsine complexes of niobium(v) and tantalum(v) fluorides: synthesis, properties, structures and comparisons with the corresponding chlorides

“…The diffuse reflectance UV/Vis spectra of the [MF 4 (diphosphine) 2 ][MF 6 ] show several broad features in the range 27 000-33 000 cm −1 , which for these d 0 complexes can be assigned as P(σ)→M(d) charge transfer transitions since the F(π)→M(d) charge transfer bands are expected to occur in the far-UV. 12 For those phosphines containing aromatic groups, there are also π→π* transitions in the near-UV region. Comparisons with the corresponding [MCl 4 (diphosphine) 2 ][MCl 6 ] ( Table 2) show that the P(σ)→M(d) charge transfer bands occur at higher energy in the fluorides, an effect observed in other systems, 7,10 and expected due to the strong M-F bonding which raises the energy of the metal d-orbitals.…”

Absorption and magnetic circular dichroism spectra of hexafluoroosmate(IV) and hexafluoroiridate(IV) in the cubic host dicesium hexafluorogermanate

“…For Cs2GeF6:Os4+, the ligand field parameters B = 625 cm'1, C = 2969 cm'1, Dq = 2450 cm'1, and f = 2800 cm'1 have been chosen, first, to fit the four most definitive assignments ( ,, (3Tlg), T"<2> (3Tlg), T2g (3EgW), and T" (3Alg)) and, second, to give a reasonable fit of all of the assigned states. Throughout our parameter variations, we have used the same C/B ratio (4.75) employed by Allen et al [9][10][11][12][13][14][15] in their analysis of the diffuse reflectance spectrum of OsF62'. However, our resultant B and C values are higher than theirs (5 = 500 cm'1, C = 2375 cm'1) and give a considerably higher nephelauxetic ratio, ß (=Ba>mpltx/Bh(x ion where Bfree ion = 677 cm 19), specifically, 0.92 vs. 0.74.…”

Revisiting the role of octahedral symmetry in the interpretation of spectroscopic properties of [OsF6]2− and PtF6 complexes

“…3 Some years later, Warren et al performed a similar study considering a strong ligand field with similar results. 5 In both cases, good qualitative agreement with experimental results was obtained but not with numerical accuracy.…”

“…The electronic structure and molecular properties of discrete hexafluorides of late transition metals have been a central topic for both experimentalists and theoreticians for a long period of time. [1][2][3][4][5][6] The central discussion had turned around molecular symmetry and its role in the interpretation of their spectroscopic properties in a series of Re, Os, Ir, and Pt hexafluorides, among others. [1][2][3][4][5][6] The classical matrix isolation work of Holloway et al, using high-resolution spectroscopy techniques, showed that the neutral hexafluorides of those metals are all octahedral (O h ) with two characteristic vibrational modes between 200 and 300 cm −1 and 700 and 750 cm −1 , which are minimally affected by Jahn-Teller distortion.…”

“…[1][2][3][4][5][6] The central discussion had turned around molecular symmetry and its role in the interpretation of their spectroscopic properties in a series of Re, Os, Ir, and Pt hexafluorides, among others. [1][2][3][4][5][6] The classical matrix isolation work of Holloway et al, using high-resolution spectroscopy techniques, showed that the neutral hexafluorides of those metals are all octahedral (O h ) with two characteristic vibrational modes between 200 and 300 cm −1 and 700 and 750 cm −1 , which are minimally affected by Jahn-Teller distortion. 1 Similar results were obtained, more recently, by Richardson et al using gas-phase electron diffraction.…”