Insertion of a Transient Tin Nitride into Carbon–Carbon and Boron–Carbon Bonds
Insertion of a Transient Tin Nitride into Carbon–Carbon and Boron–Carbon Bonds
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将瞬态氮化锡插入碳-碳和硼-碳键中
DOI：
10.1021/acs.inorgchem.7b02413
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发表时间：
2017
影响因子：
4.6
通讯作者：
Power, Philip P.
中科院分区：
文献类型：
--
作者：
Wang, Shuai;Tao, Lizhi;Stich, Troy A.;Olmstead, Marilyn M.;Britt, R. David;Power, Philip P.
[AriPr_4Sn（μ-Cl）]_2（1）与叠氮化钠发生简单的交换反应，以85%的产率合成了双桥连叠氮化锡[AriPr_4Sn（μ-N_3）]_2（2）（AriPr_4 = C_6H_3_2，6（C_6H_3_2，6-iPr_2）_2）。2的乙醚溶液的光解。16 h得到氮杂卓基取代的插入产物[C6 H3 -2-（C6 H3 - 2，6-iPr 2）-6-（C6 H3 N-3，7-iPr 2）Sn]2（3）。刘易斯酸B（C6 F5）3（BCF）或刘易斯碱吡啶与2反应，使二聚体解离，得到相应的络合单体叠氮化锡，其中BCF与α-氮配位的AriPr 4SnN 3 BCF（4），或其中吡啶与锡原子配位的AriPr 4Sn（吡啶）N3（6）。4在乙醚中光解12小时，叠氮基的α-氮插入BCF受体的一个B-C键中，生成氨基锡（II），AriPr 4SnN（C6 F5）B（C6 F5）2（5）。相反，6的光解超过36小时没有得到明显的反应。一个高度反应性的锡氮化物中间体，AriPr 4Sn N，提出作为形成3和5作为捕获锡为中心的自由基异构体的结果的机理途径的一部分。这是通过立即冷冻样品2或4后，约。30分钟的紫外光分解，并记录它们的电子顺磁共振谱。它们的菱形张量为[g1，g2，g3] = [2.029，1.978，1.933]。这种自由基中间体可能与氮化物[−SnIV <$N]中间体的价态异构体有关，与氮烯[−SnII-N]和氮吡啶基[−SnIII <$N·]形式处于异构平衡，但氮上的自旋密度被淬灭，可能是通过H原子的夺取形成S = 1/2的分子式为−Sn·<$N（H）的物质。
A simple exchange reaction between [AriPr4Sn(μ-Cl)]2(1) and sodium azide afforded the doubly bridged Sn(II) azide, [AriPr4Sn(μ-N3)]2(2) (AriPr4= C6H3-2,6(C6H3-2,6-iPr2)2) in 85% yield. Photolysis of a diethyl ether solution of2for ca. 16 h yielded an azepinyl-substituted insertion product, [C6H3-2-(C6H3-2,6-iPr2)-6-(C6H3N-3,7-iPr2)Sn]2(3). The reaction of the Lewis acid, B(C6F5)3(BCF), or the Lewis base, pyridine, with2dissociates the dimer to afford the corresponding complexed monomeric Sn(II) azide, AriPr4SnN3BCF (4) in which BCF coordinates the α-nitrogen, or AriPr4Sn(pyridine)N3(6) in which pyridine coordinates to the tin atom. Photolysis of4in diethyl ether for 12 h results in the insertion of the α-nitrogen of the azide group into one of the B–C bonds of the BCF acceptor to yield the tin(II) amide, AriPr4SnN(C6F5)B(C6F5)2(5). In contrast, photolysis of6for over 36 h afforded no apparent reaction. A highly reactive Sn nitride intermediate, AriPr4SnN, is proposed as part of the mechanistic pathway for the formation of3and5as a result of trapping the tin-centered radical isomers. This was effected by immediate freezing the samples of2or4after ca. 30 min of UV photolysis and recording their electron paramagnetic resonance spectra. These exhibited a rhombicgtensor of [g1,g2,g3] = [2.029, 1.978, 1.933]. This radical intermediate could be related to the valence isomers of the nitride [−SnIVN] intermediate, in isomeric equilibrium with the nitrene [−SnII–N] and nitridyl [−SnIIIN·] forms, but with the spin density on the nitrogen being quenched, possibly by the H atom abstraction to form anS= 1/2 species of formula −Sn·N(H).