Redox properties of dihalogermylenes, dihalostannylenes and their complexes with Lewis bases

• Published in: Journal of organometallic chemistry 1995-09, Vol.499 (1), p.27-34
• Main Authors: Lee, V.Ya, Basova, A.A., Matchkarovskaya, I.A., Faustov, V.I., Egorov, M.P., Nefedov, O.M., Rakhimov, R.D., Butin, K.P.
• Format: Article
• Language: English
• Subjects: AM1 calculations; Electrochemistry; Germanium; Germylenes; Stannylenes; Tin
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(95)00320-P

Reduction and oxidation potentials of GeI 2, GeBr 2 · B (B = dioxane, PPh 3), GeCl 2 · (B = dioxane, PPh 3, AsPh 3, Py, dip), SnCl 2 · dioxane, SnX 2 (X = F, Cl Br, I) were measured in MeCN at 20 °C. The data obtained indicate that in many cases the EX 2 and EX 2 · B (E = Ge, Sn) can act not only as a good reducing agents, but also as strong oxidants. Examples of redox reactions in which EX 2 and EX 2 · B react as oxidizing agents were found. The variation of the redox potentials of the dihalogermylenes and dihalostannylenes with complexation and with the nature of the halogen substituent and the Lewis base is discussed. In some cases (GeI 2, GeX 2 · B; X = Cl, Br, B = dioxane, PPh 3), the reduction or oxidation was found to be quasi-reversible, indicating the presence of relatively stable ion radicals. AM1 calculations on GeCl 2 · dioxane and GeCl 2 · PH 3 complexes show that the complexation destabilizes both the highest occupied and the lowest unoccupied MOs of the carbene analogues. The complexation reduces the IP and lowers the oxidation potential; its influence on the electron affinity is not straightforward. Calculations of the ion radicals of GeCl 2 and GeCl 2 · B (B = dioxane, PH 3) show that in the ground state an unpaired electron occupies σ-MO in the cation and π-MO in anion radicals.