Department of Chemistry, University of California, Berkeley, California 94720, USA.
Dalton Trans. 2010 Oct 21;39(39):9250-63. doi: 10.1039/b925856f. Epub 2010 Apr 16.
New rhodium and iridium complexes supported by the phenyl-substituted PNP pincer ligand PNPPhH (HN(2-PPh2-4-Me-C6H3)2) (1) were synthesized. The reaction of 2 equiv. of 1 with [(COD)IrCl]2 afforded the coordination complex [(PNPPhH)Ir(COD)]Cl (2) featuring hydrogen bonding between the N–H group and the chloride anion, as characterized by NMR spectroscopy and X-ray crystallography. Reaction of 1 with [(COE)2IrCl]2 or [(COE)2RhCl]2 in benzene provided a mixture of complexes including (PNPPhH)MHCl2 (M = Ir (4), M = Rh (7)) and (PNP)M(COE) (M = Ir (5), M = Rh (8)). Alkene complexes of the type (PNPPh)M(L) (M = Ir, L = COD (3) and COE (5); M = Rh, L = COE (8) and L = ethylene (9)) were synthesized by reaction of (PNPPh)Li with the appropriate alkene chloride complexes. Reactions of silanes with 5, 8 or 9 produced silyl hydride complexes (PNPPh)MH(SiR3) (M = Ir, R = Ph (16) and R = Et (17); M = Rh, R = Ph (18), Et (19) and Ph2Cl (20)) via Si–H oxidative addition. The JSiH coupling constants for rhodium complexes 18, 19 and 20 were determined to be ca. 35 Hz, while iridium complexes 16 and 17 exhibited coupling constants less than 10 Hz. X-Ray crystal structures of 16 and 18 reveal isostructural complexes featuring a trigonal bipyramidal geometry about iridium with a mer binding of the PNPPh ligand. A hydride ligand, located from the Fourier map for 18, has a short contact of 1.83(3) Å with the silicon atom. Oxidative addition of iodomethane to 5 and 8 afforded (PNPPh)M(Me)(I)(THF) (M = Rh (14), M = Ir (12)), respectively. Arene C–H activation upon thermolysis of 12 in benzene produced (PNPPh)M(Ph)(I)(THF). Iridium silyl iodide complexes (PNPPh)IrI(SiR3) (SiR3 = SiPh3 (21), SiH2Mes (22) and SiH2Xyl (23)) resulted from addition of organosilanes to 12, via elimination of CH4.
合成了由取代的苯基 PNP 钳形配体 PNPPhH（HN(2-PPh2-4-Me-C6H3)2）（1）支持的新铑和铱配合物。2 当量 1 与[(COD)IrCl]2 的反应得到了配位配合物[(PNPPhH)Ir(COD)]Cl（2），其特征在于 N-H 基团和氯离子之间存在氢键，这通过 NMR 光谱和 X 射线晶体学得到了证实。1 与[(COE)2IrCl]2 或[(COE)2RhCl]2 在苯中的反应提供了包括(PNPPhH)MHCl2（M = Ir（4），M = Rh（7））和(PNP)M(COE)（M = Ir（5），M = Rh（8））的配合物的混合物。通过 PNPPhLi 与适当的烯烃氯配合物反应，合成了类型为(PNPPh)M(L)（M = Ir，L = COD（3）和 COE（5）；M = Rh，L = COE（8）和 L = 乙烯（9））的烯烃配合物。硅烷与 5、8 或 9 的反应通过 Si-H 氧化加成生成了硅基氢化物配合物(PNPPh)MH(SiR3)（M = Ir，R = Ph（16）和 R = Et（17）；M = Rh，R = Ph（18）、Et（19）和 Ph2Cl（20））。铑配合物 18、19 和 20 的 JSiH 偶合常数约为 35 Hz，而铱配合物 16 和 17 表现出小于 10 Hz 的偶合常数。16 和 18 的 X 射线晶体结构揭示了具有 Ir 原子三角双锥几何形状的同构配合物，其中 PNPPh 配体呈 mer 结合。从 18 的傅里叶图中确定的一个氢化物配体与硅原子之间的短接触距离为 1.83(3)Å。碘甲烷与 5 和 8 的加成反应分别得到了(PNPPh)M(Me)(I)(THF)（M = Rh（14），M = Ir（12））。12 在苯中热解时芳烃 C-H 活化生成(PNPPh)M(Ph)(I)(THF)。通过向 12 添加有机硅烷，通过消除 CH4，得到了铱硅基碘化物配合物(PNPPh)IrI(SiR3)（SiR3 = SiPh3（21）、SiH2Mes（22）和 SiH2Xyl（23））。
