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首页> 外文期刊>Chemistry: A European journal >Structures and dynamic solution behavior of cationic, two-coordinate gold(I)-π-allene complexes
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Structures and dynamic solution behavior of cationic, two-coordinate gold(I)-π-allene complexes

机译：阳离子，两坐标金（I）-π-丙二烯络合物的结构和动态溶液行为

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摘要

A family of seven cationic gold complexes that contain both an alkyl substituted π-allene ligand and an electron-rich, sterically hindered supporting ligand was isolated in >90 % yield and characterized by spectroscopy and, in three cases, by X-ray crystallography. Solution-phase and solid-state analysis of these complexes established preferential binding of gold to the less substituted C=C bond of the allene and to the allene π face trans to the substituent on the uncomplexed allenyl C=C bond. Kinetic analysis of intermolecular allene exchange established two-term rate laws of the form rate=k _1[complex]+k _2[complex][allene] consistent with allene-independent and allene-dependent exchange pathways with energy barriers of ΔG ≠ 1=17.4-18.8 and ΔG ≠ _2=15.2-17.6 kcal mol ~(-1), respectively. Variable temperature (VT) NMR analysis revealed fluxional behavior consistent with facile (ΔG ≠=8.9-11.4 kcal mol ~(-1)) intramolecular exchange of the allene π faces through ?· 1-allene transition states and/or intermediates that retain a staggered arrangement of the allene substituents. VT NMR/spin saturation transfer analysis of [{P(tBu) _2o-binaphthyl} Au(?· ~2-4,5-nonadiene)] ~+SbF _6 ~- (5), which contains elements of chirality in both the phosphine and allene ligands, revealed no epimerization of the allene ligand below the threshold for intermolecular allene exchange (ΔG ≠ _(298K)=17.4 kcal mol ~(-1)), which ruled out the participation of a ?· ~1-allylic cation species in the low-energy π-face exchange process for this complex.
机译：分离出包含烷基取代的π-丙二烯配体和富电子的，位阻的支持配体的七个阳离子金络合物，其收率> 90％，并通过光谱学和在三种情况下通过X射线晶体学进行了表征。这些配合物的固相和固相分析确定了金优先结合到丙二烯的较少取代的C = C键上，并优先结合到丙二烯π面上，而反面是未络合的烯基C = C键上的取代基。分子间烯丙二烯交换的动力学分析建立了速率= k _1 [络合物] + k _2 [络合物] [丙二烯]形式的二项速率规律，与能量依赖为ΔG≠1 =的丙二烯无关和丙二烯依赖的交换途径一致17.4-18.8和ΔG≠_2 = 15.2-17.6 kcal mol〜（-1）。可变温度（VT）NMR分析表明，通量行为与通过α·1-丙二烯过渡态和/或保留a的中间体容易地（ΔG≠= 8.9-11.4 kcal mol〜（-1））进行烯内π面的分子内交换相一致。烯丙基取代基的交错排列。 [{P（tBu）_2o-联萘基} Au（α~~ 2-4,5-壬二烯）]〜+ SbF _6〜-（5）的VT NMR /自旋饱和转移分析，其中两个元素均具有手性膦和烯丙基配体，在分子间烯丙基交换的阈值以下（ΔG≠_（298K）= 17.4 kcal mol〜（-1）），未发现烯丙基配体的差向异构化，这排除了α·〜1-烯丙基的参与阳离子物种在低能π面交换过程中为此复合物。

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