Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, E-30071 Murcia, Spain.
Inorg Chem. 2013 Apr 1;52(7):4071-83. doi: 10.1021/ic400184p. Epub 2013 Mar 14.
Ag(I) dicarbene complexes [Ag(m)(L(n))m]X(m) (L(n) = Im(Me)(CH2)(n)Im(Me), Im(Me) = N-methylimidazol-N-yl-2-ylidene; n = 3, X = PF6, m = 2; n = 6-8, 10, X = AgBr2, m = 1, 2) were prepared by reacting Ag2O with 1 equiv of the corresponding bisimidazolium salt [H2L(n)]A2 (A = PF6, Br). The dibromoargentates react with 1 equiv of AgTfO to afford Ag(m)(L(n))mm (m = 1, 2). The room temperature transmetalation reaction of [Ag(m)(L(n))m][AgBr2]m (n = 3, 5, 6-8, 10) with [AuCl(SMe2)] and AgTfO (L(n):Au:TfO = 1:1:1) affords Au2(μ-L(n))22 (n = 3, 5, 10), or mixtures of [Au(κ(2)-L(n))]TfO (main product for n = 7) and Au2(μ-L(n))22 (main product for n = 6, 8). At room temperature, the equilibrium between M2(μ-L(n))22 and [M(κ(2)-L(n))]TfO is fast for M = Ag, but slow for M = Au, in the NMR time scale. When n ≥ 7 and M = Ag or Au, the equilibrium is shifted toward the mononuclear complexes in the order 8 > 10 > 7, which proves that the (CH2)8 linker has the optimal length for trans chelation. Correspondingly, the high-temperature metalation of [H2L(n)]Br2 (n = 8, 10) with 1 equiv of [AuCl(SMe2)] and excess of NaAcO, affords [Au(κ(2)-L(n))]Br with a small amount of [Au2(μ-L(n))2]Br2. If AgTfO is added to the reaction mixture, [Au(κ(2)-L(8))]2[AgBr3] is isolated instead of the desired triflate, which can be obtained by reacting the mixture of [Au(κ(2)-L(8))]Br and [Au2(μ-L(8))2]Br2 with AgTfO. [Au(κ(2)-L(10))]TfO was isolated after thermal conversion of Au2(μ-L(10))22. [Au(κ(2)-L(8))]TfO reacts with I2 to give trans-[AuI2(κ(2)-L(8))]TfO, which is the first Au(III) complex containing a trans-spanning bidentate ligand. We have determined the crystal structures of complexes Ag2(μ-L(3))22, [Ag(κ(2)-L(7))]TfO, Au2(μ-L(3))22, [Au(κ(2)-L(8))]Br, [Au(κ(2)-L(8))]2[AgBr3], and trans-[AuI2(κ(2)-L(8))]TfO.
Ag(I) 二碳烯配合物[Ag(m)(L(n))m]X(m)（L(n)=Im(Me)(CH2)(n)Im(Me)，Im(Me)=N-甲基咪唑-N-基-2-亚基；n=3，X=PF6，m=2；n=6-8，10，X=AgBr2，m=1，2）通过 Ag2O 与相应的双咪唑盐[H2L(n)]A2（A=PF6，Br）反应 1 当量制备。二溴化银与 1 当量的 AgTfO 反应生成Ag(m)(L(n))mm（m=1，2）。室温下，[Ag(m)(L(n))m][AgBr2]m（n=3，5，6-8，10）与[AuCl(SMe2)]和 AgTfO（L(n)：Au：TfO=1：1：1）的反transmetalation 反应生成Au2(μ-L(n))22（n=3，5，10），或[Au(κ(2)-L(n))]TfO（主要产物为 n=7）和Au2(μ-L(n))22（主要产物为 n=6，8）的混合物。在室温下，对于 M=Ag，M2(μ-L(n))22 和[M(κ(2)-L(n))]TfO 之间的平衡在 NMR 时间尺度上很快，但对于 M=Au 则很慢。当 n≥7 且 M=Ag 或 Au 时，平衡向单核配合物移动，顺序为 8>10>7，这证明了（CH2）8 链接器具有用于反 chelation 的最佳长度。相应地，[H2L(n)]Br2（n=8，10）与 1 当量的[AuCl(SMe2)]和过量的 NaAcO 的高温金属化反应得到[Au(κ(2)-L(n))]Br，其中含有少量[Au2(μ-L(n))2]Br2。如果向反应混合物中加入 AgTfO，则会分离出[Au(κ(2)-L(8))]2[AgBr3]而不是所需的三氟甲磺酸酯，后者可以通过反应混合物[Au(κ(2)-L(8))]Br 和[Au2(μ-L(8))2]Br2与 AgTfO 得到。[Au(κ(2)-L(10))]TfO 在Au2(μ-L(10))22 的热转化后被分离出来。[Au(κ(2)-L(8))]TfO 与 I2 反应生成反式-[AuI2(κ(2)-L(8))]TfO，这是第一个含有反式桥联双齿配体的 Au(III)配合物。我们已经确定了配合物Ag2(μ-L(3))22、[Ag(κ(2)-L(7))]TfO、Au2(μ-L(3))22、[Au(κ(2)-L(8))]Br、[Au(κ(2)-L(8))]2[AgBr3]和反式-[AuI2(κ(2)-L(8))]TfO 的晶体结构。
