A new iron complex mediates stereospecifichydroxylation of alkyl C-H bonds with hydrogen peroxide, exhibiting excellent efficiency. Isotope labelling studies provide evidence that the relative reactivity of tautomerically related oxo-iron species responsible for the C-H hydroxylation reaction is dominated by steric factors.
Polydentate pyridyl ligands and the catalytic activity of their iron(II) complexes in oxidation reactions utilizing peroxides as the oxidants
作者:Matthew Lenze、Sergey L. Sedinkin、Eike B. Bauer
DOI:10.1016/j.molcata.2013.03.006
日期:2013.7
activity in that solvent. For the complexes [Fe(10)2](OTf)2 (two tridentate ligands), [Fe(12)(OTf)2] (one tetradentate ligand) and [Fe(16)(OTf)](OTf) (one pentadentate ligand), the product formation for a test reaction was followed over time at significantly reduced catalyst loading to determine activities. Under these conditions, the complex [Fe(10)2](OTf)2 exhibited a somewhat lower catalytic activity
Mechanistically Driven Development of an Iron Catalyst for Selective <i>Syn</i>-Dihydroxylation of Alkenes with Aqueous Hydrogen Peroxide
作者:Margarida Borrell、Miquel Costas
DOI:10.1021/jacs.7b07909
日期:2017.9.13
to be resolved in the design of iron catalysts for olefin syn-dihydroxylation with potential utility in organic synthesis. Toward this end, in this work a novel catalyst bearing a sterically encumbered tetradentate ligand based in the tpa (tpa = tris(2-methylpyridyl)amine) scaffold, [FeII(CF3SO3)2(5-tips3tpa)], 1 has been designed. The steric demand of the ligand was envisioned as a key element to support
catalysts for efficient and selective alkene oxidation (epoxidation and cis‐dihydroxylation) employing hydrogenperoxide as oxidant. Complex [Fe(II)(Me,Me,HPyTACN)(CF3SO3)2] (7), was identified as the most efficient and selective cis‐dihydroxylation catalyst among the family. The high activity of 7 allows the oxidation of alkenes to proceed rapidly (30 min) at room temperature and underconditions where the
通式为[Fe(II)(R,Y,X PyTACN)(CF 3 SO 3)2 ]的铁络合物家族,其中R,Y,X PyTACN = 1‐ [2′‐(4‐Y‐6 -[X-吡啶基)甲基] -4,7-二烷基-1,4,7-三氮杂环壬烷,X和Y分别表示吡啶的4和6位上的基团,R表示在N-处的烷基取代基三氮杂双环壬烷环的4和N-7被证明是使用过氧化氢作为氧化剂进行有效且选择性的烯烃氧化(环氧化和顺式-二羟基化)的催化剂。络合物[Fe(II)(Me,Me,H PyTACN)(CF 3 SO 3)2 ](7)被认为是该家族中最有效和选择性最强的顺式-二羟基化催化剂。7的高活性使烯烃的氧化在室温下以及在不大量使用烯烃而仅是限制性试剂的条件下迅速进行(30分钟)。在3%(摩尔)的存在下7,2当量。H 2 O 2作为氧化剂,当量为15当量。在乙腈溶液中,水被烯烃顺式-二羟基化,其收率可能对于合成目的是令人感兴趣的。竞
Nonheme Fe(IV) Oxo Complexes of Two New Pentadentate Ligands and Their Hydrogen-Atom and Oxygen-Atom Transfer Reactions
作者:Mainak Mitra、Hassan Nimir、Serhiy Demeshko、Satish S. Bhat、Sergey O. Malinkin、Matti Haukka、Julio Lloret-Fillol、George C. Lisensky、Franc Meyer、Albert A. Shteinman、Wesley R. Browne、David A. Hrovat、Michael G. Richmond、Miquel Costas、Ebbe Nordlander
DOI:10.1021/ic5029564
日期:2015.8.3
that the ligand field weakens as ligand pyridyl substituents are progressively substituted by (N-methyl)benzimidazolyl moieties. The reactivities of 3 and 4 in hydrogen-atom transfer (HAT) and oxygen-atomtransfer (OAT) reactions show that both complexes exhibit enhanced reactivities when compared to the analogous N4Py complex ([FeIV(O)(N4Py)]2+), and that the normalized HAT rates increase by approximately
基于N4Py(N4Py = N,N-双(2-吡啶基甲基)-N-双(2-吡啶基)甲胺)骨架,合成了两个新的五齿N5}供体配体,即。[ Ñ - (1-甲基-2-苯并咪唑基)甲基- ñ - (2-吡啶基)甲基- ñ - (双- 2-吡啶基甲基)胺](大号1)和[ Ñ N'-双(1-甲基-2- -苯并咪唑基)-N-(双-2-吡啶基甲基)胺](L 2),其中N4Py的一个或两个吡啶基臂已被相应的含(N-甲基)苯并咪唑基的臂取代。络合物[Fe II(CH 3CN)(L)] 2+(L = L 1(1); L 2(2))合成,这些亚铁配合物与碘基苯的反应导致形成了铁配合物[Fe IV(O)(L )] 2+(L = L 1(3); L 2(4)),其特征在于紫外可见光谱,高分辨率质谱和Mössbauer光谱。配合物3和4在室温40 h(L = L 1)和2.5 h(L =L 2)。1和2的氧化还原电势以及