Mixed Metal Multinuclear Cr(III) Cage Compounds and Coordination Polymers Based on Unsubstituted Phenolate: Design, Synthesis, Mechanism, and Properties

Oxidative substitution reactions of chromium­(II) chloride with lithium phenoxide in the presence of water give access to new polynuclear chromium­(III) aryloxide complexes and coordination polymers. While a one-dimensional coordination polymer based on chromium­(III), [Cr₂(μ₃-OPh)₂­(μ-OPh)₆­(μ-OH)­(μ₃-Li)₄­(μ₃-Cl)₂­Li­(THF)₆]_<i>n</i>, is first obtained by serendipity, the controlled addition of water to the initial Cr­(II) complex as well as variation of the stoichiometry lead to three new discrete chromium­(III) aggregates, namely, [Cr­(OPh)₄­(μ-OH)­Li₂(THF)₃]₂, [Cr₃Li₃­(OPh)₉­(μ₃-OH)­(μ₃-O)­(THF)₆], and [Cr₄(μ-OPh)₈­(μ₃-OH)₆­(μ-OH)₂­Cl₂Li₆­(THF)­6]·2THF. The use of deuterated species allowed confirmation of the oxidation based on the addition of water by detection of H₂, HD, and D₂. During these investigations, we have also identified a THF-adduct of chromium­(II) chloride, [CrCl₂(THF)₂], used in the literature as a precursor in numerous syntheses, but with a hitherto unknown structure