Gorantla Sai Manoj N V T, Mondal Kartik Chandra
Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India.
Chem Asian J. 2022 Oct 4;17(19):e202200572. doi: 10.1002/asia.202200572. Epub 2022 Aug 19.
Metal ions-based inorganic-organic hybrid composites are often reported acting as good to excellent catalysts with various substrate scopes under milder reaction conditions. The active catalyst of a catalytic cycle is sometimes proposed to be a short-lived reactive intermediate species. A three coordinate (L-Me)Ni(II) intermediate species [L-Me=O N donor dianionic ligand] can bind with short-lived carbene-ester ligands to produce four coordinate Ni(II) species which can act as carbene transfer intermediate under suitable reaction conditions for C-H functionalization and/or cyclopropanation reactions. The dissociation of phosphine (PPh ) from the Ni(II) centre of (L-Me)Ni(II)(PPh ) (1 a) and binding of short lived carbene esters (:CR -CO R ; R =H, Ph; R =aliphatic group; 2-4 and other carbenes; 5-10) to Ni(II) rationalize the phenomenon in solution. Air stable Ni(0)-olefin complexes/intermediates (12-18) have recently been shown to mediate a variety of organic transformations. This analysis will further help organic/organometallic chemists to rationalize the design and synthesis of future catalysts for organic transformation. EDA-NOCV calculations have been performed to shed light on the stability and bonding of those species. Additionally, our analysis provides a proper reason why the analogous (L-Me)Pd-PPh complex (1 b) does not dissociate in solution and hence, a similar catalytic product has not been isolated from identical reaction conditions. The stability and the labile nature of Ni(II/0) complexes have been investigated by state-of-the-art EDA-NOCV analyses.
基于金属离子的无机-有机杂化复合材料常被报道在较温和的反应条件下，对各种底物范围表现出良好到优异的催化性能。催化循环中的活性催化剂有时被认为是一种短寿命的反应性中间体物种。一种三配位的（L-Me）Ni（II）中间体物种[L-Me = 含氮供体的二价阴离子配体]可以与短寿命的卡宾酯配体结合，生成四配位的Ni（II）物种，该物种在适合C-H官能化和/或环丙烷化反应的条件下可作为卡宾转移中间体。膦（PPh₃）从（L-Me）Ni（II）（PPh₃）（1 a）的Ni（II）中心解离，以及短寿命的卡宾酯（:CR₁-CO₂R₂；R₁ = H，Ph；R₂ = 脂肪族基团；2 - 4以及其他卡宾；5 - 10）与Ni（II）结合，解释了溶液中的这一现象。最近已表明，空气稳定的Ni（0）-烯烃配合物/中间体（12 - 18）可介导多种有机转化。该分析将进一步帮助有机/有机金属化学家合理设计和合成未来用于有机转化的催化剂。已进行EDA-NOCV计算以阐明这些物种的稳定性和键合情况。此外，我们的分析提供了一个恰当的理由，解释了类似的（L-Me）Pd-PPh₃配合物（1 b）为何在溶液中不解离，因此在相同反应条件下未分离出类似的催化产物。已通过最先进的EDA-NOCV分析研究了Ni（II/0）配合物的稳定性和不稳定性质。
