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]n, 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.氯化铬(II)与苯酚锂在水存在下发生氧化取代反应，可合成得到新型多核铬(III)芳氧基配合物（polynuclear chromium(III) aryloxide complexes）与配位聚合物（coordination polymers）。尽管首次意外得到了基于铬(III)的一维配位聚合物（one-dimensional coordination polymer）：[Cr2(μ3-OPh)2(μ-OPh)6(μ-OH)(μ3-Li)4(μ3-Cl)2Li(THF)6]n，但通过向初始铬(II)配合物中可控添加水以及调整化学计量比，我们得到了三种新型离散型铬(III)聚集体，分别为[Cr(OPh)4(μ-OH)Li2(THF)3]2、[Cr3Li3(OPh)9(μ3-OH)(μ3-O)(THF)6]以及[Cr4(μ-OPh)8(μ3-OH)6(μ-OH)2Cl2Li6(THF)6]·2THF。借助氘代物种，通过检测H2、HD与D2，我们证实了加水引发的氧化反应。在本研究过程中，我们还确认了氯化铬(II)的四氢呋喃（THF）加合物[CrCl2(THF)2]——该化合物在已有文献中被用作诸多合成反应的前驱体，但其结构此前尚未被解析。