Wong Kai-Hong, Cheung Wai-Man, Pham Hoang-Long, So Yat-Ming, Sung Herman H-Y, Williams Ian D, Leung Wa-Hung
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China.
Inorg Chem. 2021 Feb 15;60(4):2261-2270. doi: 10.1021/acs.inorgchem.0c03105. Epub 2021 Jan 27.
Tetravalent cerium alkoxide complexes supported by the Kläui tripodal ligand [Co(η-CH){P(O)(OEt)}] (L) have been synthesized, and their nucleophilic and redox reactivity have been studied. Treatment of the Ce(IV) oxo complex [Ce(L)(O)(HO)]·MeCONH () with PrOH or reaction of [Ce(L)Cl] () with AgO in PrOH afforded the Ce(IV) dialkoxide complex [Ce(L)(OPr)] (). The methoxide and ethoxide analogues [Ce(L)(OR)] (R = Me (), Et ()) have been prepared similarly from and AgO in ROH. Reaction of with an equimolar amount of yielded a new Ce(IV) complex that was formulated as the chloro-alkoxide complex [Ce(L)(OPr)Cl] (). Treatment of with HX and methyl triflate (MeOTf) afforded [Ce(L)X] (X = Cl, NO, PhO) and [Ce(L)(OTf)], respectively, whereas treatment with excess CO in hexane led to isolation of the Ce(IV) carbonate [Ce(L)(CO)]. reacted with water in hexane to give a Ce(III) complex and a Ce(IV) species, presumably the reported tetranuclear oxo cluster [Ce(L)(O)(OH)]. The Ce(IV) alkoxide complexes are capable of oxidizing substituted phenols, possibly via a proton-coupled electron transfer pathway. Treatment of with ArOH afforded the Ce(III) aryloxide complexes [Ce(L)(OAr)] (Ar = 2,4,6-tri--butylphenyl (), 2,6-diphenylphenyl ()). On the other hand, a Ce(III) complex containing a monodeprotonated 2,2'-biphenol ligand, [Ce(L)(BuCHOH)] () (BuCHOH = 4,4',6,6'-tetra--butyl-2,2'-biphenol), was isolated from the reaction of with 2,4-di--butylphenol. The crystal structures of complexes , , , and - have been determined.
由Kläui三脚架配体[Co(η-CH){P(O)(OEt)}]（L）支撑的四价铈醇盐配合物已被合成，并对其亲核反应性和氧化还原反应性进行了研究。用PrOH处理Ce(IV)氧代配合物[Ce(L)(O)(HO)]·MeCONH（）或在PrOH中使[Ce(L)Cl]（）与AgO反应，得到Ce(IV)二烷氧基配合物[Ce(L)(OPr)]（）。甲醇盐和乙醇盐类似物[Ce(L)(OR)]（R = Me（），Et（））已通过在ROH中由和AgO类似地制备。与等摩尔量的反应生成了一种新的Ce(IV)配合物，其被配制成氯代烷氧基配合物[Ce(L)(OPr)Cl]（）。用HX和甲基三氟甲磺酸酯（MeOTf）处理得到[Ce(L)X]（X = Cl，NO，PhO）和[Ce(L)(OTf)]，而在己烷中用过量CO处理导致分离出Ce(IV)碳酸盐[Ce(L)(CO)]。在己烷中与水反应生成一种Ce(III)配合物和一种Ce(IV)物种，推测是报道的四核氧簇[Ce(L)(O)(OH)]。Ce(IV)醇盐配合物能够氧化取代酚，可能是通过质子耦合电子转移途径进行。用ArOH处理得到Ce(III)芳氧基配合物[Ce(L)(OAr)]（Ar = 2,4,6-三叔丁基苯基（），2,6-二苯基苯基（））。另一方面，从与2,4-二叔丁基苯酚的反应中分离出一种含有单去质子化2,2'-联苯酚配体的Ce(III)配合物，[Ce(L)(BuCHOH)]（）（BuCHOH = 4,4',6,6'-四叔丁基-2,2'-联苯酚）。配合物、、、和-的晶体结构已被确定。
