Trigonal-planar-coordinated organogold(I) complexes stabilized by organometallic 1,4-diynes: Reaction behavior, structure, and bonding
Trigonal-planar-coordinated organogold(I) complexes stabilized by organometallic 1,4-diynes: Reaction behavior, structure, and bonding
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DOI：
10.1021/om970302i
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发表时间：
1997-11-11
期刊：
影响因子：
2.8
通讯作者：
Lang, H
中科院分区：
文献类型：
--
作者：
Kohler, K;Silverio, SJ;Lang, H
双(炔基)二茂钛 [Ti](C=CR1)(C=CR2) ([Ti] = (eta(6)-C5H4SiMe3)(2)Ti;la R-1 = R-2 = SiMe3;Ib R-1 = R-2 = Bu-t;1c R-1 = SiMe3, R-2 = Bu-t) 与 (C5H5N)AuCl3 (2) 的反应，描述了 LAuCl (5a, L = PPh3; 5b, L = SMe2) 以及 (Me2S)AuR3 (6b, R-3 = C=CSiMe3; 6c, R-3 = C=(CBu)-Bu-t; 6d, R-3 = C6H2(CF3)(3)-2,4,6; 6e, R-3 = Me)。用(C5H5N)AuCl3(2)处理[Ti](C=CSiMe3)(2)(la)产生[Ti]Cl-2(3)和Me3SiC=C-C=CSiMe3(4a)以及Au(O)。然而，线性二配位氯化金 (I) LAuCl (5a,b) 与 la 反应产生不同的产物，具体取决于所使用的路易斯碱。在 Ph3P 供体稳定的氯化金 (I) 5a 的反应中，得到二茂钛二氯化物 (3) 以及 (Ph3P)AuC=CSiMe3 (6a)，与适当的 Me2S 供体稳定的分子 5b 反应，得到二茂钛二氯化物 (3) 以及异双金属镊子分子形成{[Ti](C=CSiMe3)(2)}AuC=CSiMe3(7a)。讨论了不同化学行为的可能机制。同样，后一类型的分子（化合物7a-e）可以通过[Ti](C=CR1)(C=CR2)(la-c)与(Me2S)AuR3(6b-e)的反应以更高的产率合成。在异双金属钛-金配合物{[Ti](C=CR1)(C=CR2)}AuR3 (7a, R-1 = R-2 = SiMe3, R-3 = C=CSiMe3; Tb, R-1 = R-2 = Bu-t, R-3 = C=(CBu)-Bu-t; 7c, R-1 = SiMe3, R-2 = Bu-t, R-3 = C=CSiMe3; 7d, R-1 = R-2 = SiMe2, R-3 = C6H2(CF3)(3)-2,4,6; 7e, R-1 = R-2 = SiMe3, R-3 = Me)，存在三角平面环境中的低价单体有机金 (I) 部分，通过有机金属 pi 镊子的螯合效应稳定双(炔基)二茂钛。选定的有机金(I)络合物的热解在消除双(炔基)二茂钛片段后提供偶联产物R-3-R-3 (4)和金膜。报告了化合物 7a、7b 和 7d 的 X 射线结构分析。发现所有化合物中都存在短钛-金键长（7a，3.007(2)埃；7b，2.975(1)埃；7d，2.995(1)埃）。计算表明，Au-R-3 单体与有机金属 pi 镊子双（炔基）二茂钛的络合是通过四中心双电子键描述的。单体有机金（I）部分通过双（炔基）二茂钛和 Au-R-3 物质之间电子密度的协同面内捐赠和反捐赠来稳定。直接的供体-受体金-钛相互作用有助于这种稳定。
The reaction of the bis(alkynyl) titanocenes [Ti](C=CR1)(C=CR2) ([Ti] = (eta(6)-C5H4SiMe3)(2)Ti; la R-1 = R-2 = SiMe3; Ib R-1 = R-2 = Bu-t; 1c R-1 = SiMe3, R-2 = Bu-t) With (C5H5N)AuCl3 (2), LAuCl (5a, L = PPh3; 5b, L = SMe2) as well as (Me2S)AuR3 (6b, R-3 = C=CSiMe3; 6c, R-3 = C=(CBu)-Bu-t; 6d, R-3 = C6H2(CF3)(3)-2,4,6; 6e, R-3 = Me) is described. Treatment of [Ti](C=CSiMe3)(2) (la) with (C5H5N)AuCl3 (2) produces [Ti]Cl-2 (3) and Me3SiC=C-C=CSiMe3 (4a) together with Au(O). However, the linear two-coordinated gold(I) chlorides LAuCl (5a,b) react with la to afford different products, depending on the Lewis bases applied. While in the reaction of the Ph3P donor-stabilized gold(I) chloride 5a, the titanocene dichloride (3) along with (Ph3P)AuC=CSiMe3 (6a) is obtained, with the appropriate Me2S donor-stabilized molecule 5b, the titanocene dichloride (3) along with the heterobimetallic tweezer molecule {[Ti](C=CSiMe3)(2)}AuC=CSiMe3 (7a) is formed. A possible mechanism for the different chemical behavior is discussed. Likewise, molecules of the latter type (compounds 7a-e) can be synthesized in much better yields by the reaction of [Ti](C=CR1)(C=CR2) (la-c) with (Me2S)AuR3 (6b-e). In the heterobimetallic titanium-gold complexes {[Ti](C=CR1)(C=CR2)}AuR3 (7a, R-1 = R-2 = SiMe3, R-3 = C=CSiMe3; Tb, R-1 = R-2 = Bu-t, R-3 = C=(CBu)-Bu-t; 7c, R-1 = SiMe3, R-2 = Bu-t, R-3 = C=CSiMe3; 7d, R-1 = R-2 = SiMe2, R-3 = C6H2(CF3)(3)-2,4,6; 7e, R-1 = R-2 = SiMe3, R-3 = Me), a low-valent monomeric organogold(I) moiety in a trigonal-planar environment is present, which is stabilized by the chelating effect of the organometallic pi-tweezer bis(alkynyl) titanocene. The thermolysis of selected organogold(I) complexes affords, on elimination of the bis(alkynyl) titanocene fragment, the coupling products R-3-R-3 (4) and gold films. The X-ray structure analyses of compounds 7a, 7b, and 7d are reported. It is found that in all compounds short titanium-gold bond lengths are present (7a, 3.007(2) Angstrom; 7b, 2.975(1) Angstrom; 7d, 2.995(1) Angstrom). Calculations show that the complexation of the Au-R-3 monomers with the organometallic pi-tweezer bis(alkynyl) titanocene is described by a four-center two-electron bond. The monomeric organogold(I) moieties are stabilized by a synergetic in-plane donation and back-donation of electron density between the bis(alkynyl) titanocene and the Au-R-3 species. A direct donor-acceptor Au-Ti interaction contributes to this stabilization.