Yan Xiaoqian, Batchelor Raymond J., Einstein Frederick W. B., Zhang Xiaoheng, Nagelkerke Ruby, Sutton Derek
Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
Inorg Chem. 1997 Mar 12;36(6):1237-1246. doi: 10.1021/ic960993v.
Reaction of CpIr(CO)(2) (3, Cp = eta(5)-C(5)Me(5)) with [N(2)Ar][BF(4)] (Ar = p-C(6)H(4)OMe) in acetone at -78 degrees C affords the nitrogen extrusion product [CpIr(CO)(2)(Ar)][BF(4)] (5), but in dichloromethane it yields a dinuclear product [Cp(CO)(2)Ir-Ir(Cl)(CO)Cp][BF(4)] (6). By carrying out this very reaction in ethanol solution, a nitrogen-retained product [CpIr(CO)(OEt)(NHNAr)][BF(4)] (7) is obtained, containing an aryldiazene ligand. Deprotonation of 7 gives quantitatively the neutral doubly-bent aryldiazenido complex CpIr(CO)(OEt)(N(2)Ar) (8). The IR nu(CO) absorptions measured for the dinuclear compound 6 indicate no bridging carbonyl, but a (13)C NMR study in solution shows that 6 is stereochemically nonrigid at ambient temperature; its three carbonyl ligands are all involved in a fast exchange process, and this process is frozen at -86 degrees C. Exchange of the CO groups via a terminal-bridging-terminal process accompanied by rotation about the Ir-Ir axis is suggested. The molecular structure of 6 in the solid state has been established by single crystal X-ray crystallographic analysis and is consistent with the solution spectra. By reaction of [N(2)Ar][BF(4)] with the dinuclear complex CpIr(CO) (4) in acetone, the complex [{CpIr(CO)}(2)(1-eta(1)-1,2-eta(2)-p-C(6)H(4)OMe)][BF(4)] (9) with a rare sigma,pi-bridging aryl group has been obtained and crystallized. The molecular structure containing an asymmetric bridging aryl group is established for 9 in the solid state by a single crystal X-ray crystallographic analysis. However, the identical (1)H NMR features observed at ambient temperature and -90 degrees C in solution (i.e., a singlet resonance for the two Cp ligands and a symmetric AA'BB' pattern for the p-C(6)H(4)OMe) indicate a static or time-averaged symmetrical molecular geometry for 9. Compound 6 crystallizes in the monoclinic space group P2(1)/c with a = 10.583(2) Å, b = 14.256(3) Å, c= 16.818(4) Å, beta = 95.91 (2) degrees, V = 2523.9 Å(3), and Z = 4. Refinement yielded R(F)() = 0.027 and R(w)(F)() = 0.033 for 3299 observed reflections (I(o) >/= 2.5sigma(I(o))) of 4427 unique reflections. Compound 9 crystallizes in the monoclinic space group P2(1)/n with a = 11.695(2) Å, b = 19.911(3) Å, c= 12.539(2) Å, beta = 96.54(1) degrees, V = 2900.8 Å(3), and Z = 4. Refinement yielded R(F)() = 0.025 and R(w)(F)() = 0.035 for 3444 observed reflections (I(o) >/= 2.5sigma(I(o))) of 4526 unique reflections.
CpIr(CO)₂（3，Cp = η⁵-C₅Me₅）与[N₂Ar][BF₄]（Ar = p-C₆H₄OMe）在-78℃的丙酮中反应，得到氮挤出产物[CpIr(CO)₂(Ar)][BF₄]（5），但在二氯甲烷中反应则生成双核产物[Cp(CO)₂Ir-Ir(Cl)(CO)Cp][BF₄]（6）。在乙醇溶液中进行该反应，可得到含芳基重氮配体的氮保留产物[CpIr(CO)(OEt)(NHNAr)][BF₄]（7）。7去质子化定量得到中性双弯芳基重氮基配合物CpIr(CO)(OEt)(N₂Ar)（8）。对双核化合物6测得的红外ν(CO)吸收表明没有桥连羰基，但溶液中的¹³C NMR研究表明，6在室温下立体化学非刚性；其三个羰基配体都参与快速交换过程，该过程在-86℃时冻结。提出通过末端-桥连-末端过程伴随绕Ir-Ir轴旋转进行CO基团的交换。通过单晶X射线晶体学分析确定了6在固态下的分子结构，与溶液光谱一致。通过[N₂Ar][BF₄]与双核配合物[CpIr(CO)]₂（4）在丙酮中反应，得到含罕见σ,π-桥连芳基的配合物[{CpIr(CO)}₂(1-η¹-1,2-η²-p-C₆H₄OMe)][BF₄]（9）并使其结晶。通过单晶X射线晶体学分析确定了9在固态下含不对称桥连芳基的分子结构。然而，在溶液中室温及-90℃观察到相同的¹H NMR特征（即两个Cp配体的单重峰共振和p-C₆H₄OMe的对称AA'BB'模式）表明9具有静态或时间平均对称分子几何结构。化合物6以单斜空间群P2(1)/c结晶，a = 10.583(2) Å，b = 14.256(3) Å，c = 16.818(4) Å，β = 95.91 (2)°，V = 2523.9 ų，Z = 4。对4427个独立反射中3299个观测反射（Iₒ≥2.5σ(Iₒ)）进行精修，得到R(F) = 0.027，R(w)(F) = 0.033。化合物9以单斜空间群P2(1)/n结晶，a = 11.695(2) Å，b = 19.911(3) Å，c = 12.539(2) Å，β = 96.54(1)°，V = 2900.8 ų，Z = 4。对4526个独立反射中3444个观测反射（Iₒ≥2.5σ(Iₒ)）进行精修，得到R(F) = 0.025，R(w)(F) = 0.035。
