Unexpected One‐Electron Oxidation of a Secondary Phosphite Selenide Cp(CO)₂FeP(Se)(OiPr)₂ by GaCl₃ and InCl₃ – Rare Examples of Di‐ and Triselenide Formation

Abstract

The reactions of the neutral phosphonoselenoate [Cp(CO)2FeP(Se)(OiPr)2] (1) with Lewis acids (GaCl3, InCl3) produce dicationic complexes [{Cp(CO)2FeP(OiPr)2}2Sen][GaCl4]2, [n = 2 (2), 3 (3)] and [{Cp(CO)2FeP(OiPr)2}2Sen][InCl4]2 [n = 2 (4), 3 (5)] in good yields; the complexes comprise an Se3 (or Se2) chain that bridges two FpP(OiPr)2 groups [Fp = Cp(CO)2Fe]. These compounds are the one‐electron oxidation products of secondary phosphite selenide 1 by group 13 (Ga, In) trichlorides. On the other hand, the reaction of GaCl3 with (iPrO)2PSe2– (dsep) yields only the Lewis adduct tris(O,O‐diisopropyldiselenophosphate)gallium (6). The 31P NMR spectrum of 6 at 183 K reveals that the gallium(III) center is surrounded by one chelating and two pendant dsep ligands, which is in line with the obtained X‐ray structure. In addition, the two‐electron oxidation of 1 leads to phosphite [Cp(CO)2FeP(O)(OiPr)2] formation.