Synthesis, characterisation and reactivity of group 2 complexes with a thiopyridyl scorpionate ligand.
Synthesis, characterisation and reactivity of group 2 complexes with a thiopyridyl scorpionate ligand.
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具有硫代吡啶基蝎酸酯配体的第 2 族配合物的合成、表征和反应性。
DOI：
10.1039/d2dt02012b
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Stevens MP
中科院分区：
文献类型：
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作者：
Stevens MP
本文报道了前配体三（2-吡啶硫代）甲烷（HTptm）与各种碱土（AE）试剂的反应性：(1)二烷基镁试剂和(2)AE双酰胺（AE = Mg-Ba）。通过HTptm与R2Mg或[AE（N”）2的反应，确定了[Mg(Tptm)(R)] （R = Me, nBu; Tptm = {C(S-C5H4N)3}−）和[AE(Tptm)（N”）]（AE = Mg - ba； N”= {N(SiMe3)2}−）的异电配合物[Mg(Tptm)(R)]]。原配体与二烷基镁试剂反应生成[{Mg(κ3C，N,N - c {Bu}{S-C5H4N}2)(μ-S-C5H4N)}2](1)和[{Mg(κ3C，N,N - c {Me}{S-C5H4N}2)(μ-OSiMe3)}2](2)，这是由于一个烷基转移到甲烷碳上并伴随C-S键断裂。然而，双酰胺前体对Mg和Ca的反应性确实提供了靶种[AE(Tptm)(N ')] (3-AE; AE = Mg - Ca)，尽管这些被证明对配体降解过程敏感。DFT计算表明，[Mg(Tptm)(nBu)] （1m '）体系中的烷基转移和3-Ca体系中的酰胺转移是诱发Tptm配体中C-S键断裂的简单过程。还测试了3-Mg和3-Ca作为催化剂对选定的烯烃和炔烃的氢磷化反应，包括4-乙基吡啶的单氢磷化反应，该反应具有高转化率和良好的区域和立体化学控制。
Herein we report the reactivity of the proligand tris(2-pyridylthio)methane (HTptm) with various Alkaline Earth (AE) reagents: (1) dialkylmagnesium reagents and (2) AE bis-amides (AE = Mg–Ba). Heteroleptic complexes of general formulae [Mg(Tptm)(R)] (R = Me, nBu; Tptm = {C(S–C5H4N)3}−) and [AE(Tptm)(N′′)] (AE = Mg–Ba; N′′ = {N(SiMe3)2}−) were targeted from the reaction of HTptm with R2Mg or [AE(N′′)2]2. Reaction of the proligand with dialkylmagnesium reagents led to formation of [{Mg(κ3C,N,N–C{Bu}{S–C5H4N}2)(μ-S–C5H4N)}2] (1) and [{Mg(κ3C,N,N–C{Me}{S–C5H4N}2)(μ-OSiMe3)}2] (2) respectively, as a result of a novel transfer of an alkyl group onto the methanide carbon with concomitant C–S bond cleavage. However, reactivity of bis-amide precursors for Mg and Ca did afford the target species [AE(Tptm)(N′′)] (3-AE; AE = Mg–Ca), although these proved susceptible to ligand degradation processes. DFT calculations show that alkyl transfer in the putative [Mg(Tptm)(nBu)] (1m′) system and amide transfer in 3-Ca is a facile process that induces C–S bond cleavage in the Tptm ligand. 3-Mg and 3-Ca were also tested as catalysts for the hydrophosphination of selected alkenes and alkynes, including the first example of mono-hydrophosphination of 4-ethynylpyridine which was achieved with high conversions and excellent regio- and stereochemical control.