Iridium(III, 0, and -I) Complexes Stabilized by 1,1'-Bis(diphenylphosphino)ferrocene (dppf): Synthesis and Characterization. Crystal Structures of [Na(THF)5][Ir(dppf)2]·THF
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- 作者：Bruno Longato ; Lorenzo Riello ; Giuliano Bandoli ; and Giuseppe Pilloni
- 刊名：Inorganic Chemistry
- 出版年：1999
- 出版时间：June 14, 1999
- 年：1999
- 卷：38
- 期：12
- 页码：2818 - 2823
- 全文大小：90K
- 年卷期：v.38,no.12(June 14, 1999)
- ISSN：1520-510X
文摘
The iridium(I) complex stabilized by the organometallic ligand 1,1'-bis(diphenylphosphino)ferrocene (dppf),[Ir(dppf)2]+, 1, undergoes a cyclometalation reaction in solution to give the iridium(III) hydride [IrH(dppf(-H))(dppf)]+, 2, which has been isolated and characterized by spectroscopic methods. The compound is thefinal product of the intramolecular oxidative addition of the ortho C-H bond of a phenyl substituent of thediphosphine and is formed through an intermediate hydride, which has also been spectroscopically characterized.1 can be electrochemically reduced to the Ir(0) and Ir(-I) species, [Ir(dppf)2], 3, and [Ir(dppf)2]-, 4, respectively,in two reversible single-electron processes. These low-valent metal complexes have been obtained by chemicalreduction of 1 with sodium naphthalenide in tetrahydrofuran solution and their crystal and molecular structuresdetermined by single-crystal X-ray analyses. 3 crystallizes in the triclinic system, space group P
ages/entities/onemacr.gif">, with a =13.019(4) Å, b = 13.765(6) Å, c = 15.549(5) Å, ages/gifchars/alpha.gif" BORDER=0> = 93.74(3)ages/entities/deg.gif">, ages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 90.35(3)ages/entities/deg.gif">, ages/gifchars/gamma.gif" BORDER=0 > = 92.07(3)ages/entities/deg.gif">, V = 2779(2) Å3,and Z = 2. Anionic complex 4 crystallizes as sodium-solvated salt [Na(THF)5][Ir(dppf)2]·THF, 4b, in which thesodium cation is surrounded by five molecules of THF in a slightly distorted trigonal-bipyramidal environment.4b crystallizes in the monoclinic system, space group P21/n, with a = 13.325(3) Å, b = 23.976(5) Å, c = 26.774(7)Å, ages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 98.77(2)ages/entities/deg.gif">, V = 8454(4) Å3, and Z = 4. The coordination geometry around the metal in neutral d9 complex3 is intermediate between the highly distorted square-planar geometry, found earlier in cationic d8 species 1, andthe almost regular tetrahedral arrangement of the two diphosphines in the anionic d10 complex 4. Reduction ofIr(I) to Ir(0) and Ir(-I) causes a stepwise decrease of the Ir-P bond length of 0.04 Å (average) and 0.05 Å,respectively, with a concomitant increase of the bite angle of the diphosphine which ranges from 94.3ages/entities/deg.gif"> (average)in [Ir(dppf)2]+ to 102.3ages/entities/deg.gif"> in [Ir(dppf)2]-.