Polyphenylchromium(III) organometallics with various phenylation degrees and stabilized by diverse Lewis bases with various donor strengths and denticity were investigated in order to better understand the formation of (η⁶-arene)chromium complexes according to the procedure of Franz Hein (1892–1976) [ Organometallics 2019, 38, 498−511, DOI: 10.1021/acs.organomet.8b00811]. Part II focuses on hexa-, penta-, and tetraphenylchromates(III). Chromium(III) compounds with a lower phenylation degree will be discussed in a future part III. The numbering scheme of the complexes relates to the number of Cr-bound phenyl substituents. Hexaphenylchromate(III): The reaction of Ph₃Cr(thf)₃·0.25dx (3) (dx = 1,4-dioxane) with an ethereal solution of phenyllithium yields yellow-orange [Li₃CrPh₆(thf)_2.3(OEt₂)_0.7] (6-thf-OEt₂) which slowly degrades in contact with the reaction solution leading to emerald-green crystals of [{(Et₂O)Li}₂Ph₃Cr(μ-O)]₂ (3-Li₂O). Pentaphenylchromate(III): Compound 6-thf-OEt₂ reacts with 1 equiv of HCl–OEt₂ solution to turquoise [{(thf)₂Li}{(Et₂O)Li}CrPh₅] (5-thf-OEt₂) that reacts with THF to the green contact ion pair [{(thf)₂Li}₂CrPh₅] (5-thf) and with 12-crown-4 (12C4) to the light green solvent-separated ion pair [(12C4)Li(thf)]₂ [CrPh₅] (5-thf-12C4). Refluxing of 5-thf-OEt₂ in diethyl ether leads to ether degradation and formation of 3-Li₂O, whereas 5-thf-12C4 liberates biphenyl under similar reaction conditions. Tetraphenylchromate(III): The reaction of 3 with 1 equiv of phenyllithium in THF leads to a green reaction mixture. At −50 °C, red [(thf)₄Li] [cis-(thf)₂CrPh₄]·2THF (4-thf) crystallizes which reversibly transforms into a green oil above −50 °C. Upon acidolysis of 5-thf-OEt₂ with 1 equiv of HCl–OEt₂ at −20 °C, the intermediately formed red complex is reduced to the dinuclear chromate(II) [{(thf)Li}CrPh₃]₂ (3-Cr^II-thf) (Cr–Cr 187.66(8) pm). Recrystallization of this product from THF yields solvent-separated [(thf)₄Li]₂ [(CrPh₃)₂] (3-Cr^II-thf₄) with a Cr–Cr quadruple bond (Cr–Cr 183.7(2) pm) without contacts between the lithium ions and Cr-bound phenyl groups. Complex 3-Cr^II-thf reacts at room temperature in diethyl ether to the sandwich complexes bis(biphenyl)chromium(0) [(η⁶-Ph₂)₂Cr⁰] (π-4) and benzene-biphenylchromium(0) [(η⁶-C₆H₆)(η⁶-Ph₂)Cr⁰] (π-3). Compounds in bold letters are authenticated by X-ray structure determinations.

中文翻译：

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弗朗茨·海因（Franz Hein）（第II部分）问世100年后重新审视苯基铬（III）化学：从Li _n CrPh _{3+ n}（thf）_x（n = 1，2，3）到二聚三苯基铬酸酯（II）配合物

Polyphenylchromium（III）与不同的苯基化有机金属度，并通过与各种供体的长处和齿合度不同的路易斯碱稳定的，以便进行了研究，以更好地理解的（η形成⁶根据弗朗兹海恩的过程-arene）铬配合物（1892至1976年）[金属有机化合物 2019，38，498-511，DOI：10.1021 / acs.organomet.8b00811]。第二部分着重于六，五和四苯基铬酸盐（III）。苯基化度较低的铬（III）化合物将在以后的第三部分中讨论。配合物的编号方案与Cr结合的苯基取代基的数目有关。六苯基铬酸盐（III）：Ph ₃ Cr（thf）₃的反应·用苯基锂的乙醚溶液溶解0.25dx（3）（dx = 1,4-二恶烷）会产生橙黄色的[Li ₃ CrPh ₆（thf）_2.3（OEt ₂）_0.7 ]（6-thf-OEt ₂）在与反应溶液接触后降解，导致生成[{（（Et ₂ O）Li} ₂ Ph ₃ Cr（μ-O）] ₂（3-Li ₂ O）的翠绿色晶体。五苯基铬酸盐（III）：化合物6-thf-OEt ₂与1当量的HCl-OEt ₂溶液反应生成绿松石[{（thf）₂Li} {（Et ₂ O）Li} CrPh ₅ ]（5-thf-OEt ₂）与THF反应生成绿色接触离子对[{（thf）₂ Li} ₂ CrPh ₅ ]（5-thf）并与12冠4（12C4）到浅绿色溶剂分离的离子对[（12C4）Li（thf）] ₂ [CrPh ₅ ]（5-thf-12C4）。5-thf-OEt ₂在乙醚中的回流导致醚降解并形成3-Li ₂ O，而5-thf-12C4在相似的反应条件下释放出联苯。四苯基铬酸酯（III）：3在THF中具有1当量的苯基锂导致产生绿色反应混合物。在−50°C下，红色[[thf）₄ Li] [顺式-（thf）₂ CrPh ₄ ]·2THF（4-thf）结晶，高于-50°C时可逆地转化为绿色油。在-20°C下用1当量的HCl–OEt ₂酸解5-thf-OEt ₂时，中间形成的红色络合物被还原为双核铬酸盐（II）[{（thf）Li} CrPh ₃ ] ₂（3 -Cr ^II -thf）（Cr-Cr 187.66（8）pm）。该产物从THF中重结晶得到溶剂分离的[（thf）₄ Li] ₂[（CrPh ₃）₂ ]（3-Cr ^II -thf ₄），具有Cr-Cr四重键（Cr-Cr 183.7（2）pm），且锂离子和Cr结合的苯基之间没有接触。复杂的3-铬^II -THF在乙醚到夹心复合物双（联苯基）铬（0）室温下进行反应[（η ⁶ -Ph ₂）₂的Cr ⁰ ]（π-4 ）和苯biphenylchromium（0） [（η ⁶ -C ₆ H ^ ₆）（η ⁶ -Ph ₂）的Cr ⁰ ]（π-3）。粗体字化合物通过X射线结构测定进行鉴定。