Synthesis and characterization of new pentamethylcyclopentadienyl iridium hydride complexes (original) (raw)
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Inorganic Chemistry, 1984
Reaction of [(dipho~)Rh(acetone)~]BF~ with mer,truns-IrHC12L3 (L = PMe2Ph, PEt2Ph, PEt3; diphos = Ph2PCH2CH2PPh2) affords the hydridebridged dinuclear complexes [(diphos)Rh(p-H)(p-Cl)IrCIL,] BF4. Solution studies show that the bridging ligands are only weakly coordinated to the rhodium. The molecular structure of 3 (L = PEt3) has been determined by X-ray diffraction: monoclinic, space group P21/c, 2 = 4, a = 11.786 (2) A, b = 19.673 (4) A, c = 22.571 (4) A, @ = 89.88 (1)O. The structure was solved by Patterson and Fourier methods using 5750 observed reflections [I 2 3u(Z)] and refined to a conventional R = 0.057. The coordination around rhodium is distorted square planar and that around iridium is distorted octahedral. The Rh-Ir distance is 2.903 (1) A, and the bridging chlorine atom is almost symmetrically bonded to the metals (Rh-Cl = 2.386 (3), Ir-CI = 2.381 (3) A). The isoelectronic complex [(diph~s)Rh(p-H)(p-Cl)IrH(PEt,)~]BF~ was obtained in a similar reaction, starting from mer,~is-IrH~Cl(PEt,)~. Its structure determined by X-ray diffraction, as above, is monoclinic, space group P21, Z = 2, a = 11.102 (2) A, b = 13.582 (3) A, c = 16.694 (4) A, @ = 85.06 (2)'. The final agreement factor (for the 4553 observed reflections) R is 0.062. As for compound 3 the coordination around Rh and Ir is distorted square planar and octahedral, respectively. There is a pronounced asymmetry in the chlorine bridge (Rh-Cl = 2.394 (5), Ir-Cl = 2.510 (5) A), and the metal-metal separation is 2.969 (2) A. t o the synthesis of cationic Rh(1)-Ir(II1) complexes. Experimental Section All operations were carried out under purified nitrogen. Solvents were distilled under nitrogen and dried prior to use. Elemental analyses were formed by the Microanalytical Section of the Swiss Federal Institute of Technology. Infrared spectra in the region 4000-400 cm-' were recorded on a Beckman IR 4250 spectrophotometer as KBr pellets or Nujol mulls. The IH and 31P{'HJ NMR spectra were recorded at 90.00 and/or 250.00 and 36.43 MHz, respectively, on a FT Bruker WH-90 or F T Bruker 250 instrument. 'H and chemical shifts are given relative to external (CH3)$i and H3P04, respectively. A positive sign denotes a shift downfield of the reference. A. Syntheses. [Rh(dipho~)(nbd)]BF,~ (nbd = norbornadiene), mer,truns-IrHCl2L3 (L = PMe2Ph, PEt2Ph, PEt3),9 and mer,cis-IrHCl2(PMePh2),,Io were prepared according to literature methods. For the preparation of mer,cis-IrH,CI(PEt,),, a toluene solution of [ (~o c)~I r C l ]~ (coc = cyclooctadiene) was reacted with 3 equiv of PEt,, and hydrogen was bubbled through the solution for 10 min, leading almost quantitatively to the product. (a) ETH-Zcntrum. (b) Taken in Dart from the Ph.D. thesis of H.L. (c)
Inorganic Chemistry, 1984
Reaction of [(dipho~)Rh(acetone)~]BF~ with mer,truns-IrHC12L3 (L = PMe2Ph, PEt2Ph, PEt3; diphos = Ph2PCH2CH2PPh2) affords the hydridebridged dinuclear complexes [(diphos)Rh(p-H)(p-Cl)IrCIL,] BF4. Solution studies show that the bridging ligands are only weakly coordinated to the rhodium. The molecular structure of 3 (L = PEt3) has been determined by X-ray diffraction: monoclinic, space group P21/c, 2 = 4, a = 11.786 (2) A, b = 19.673 (4) A, c = 22.571 (4) A, @ = 89.88 (1)O. The structure was solved by Patterson and Fourier methods using 5750 observed reflections [I 2 3u(Z)] and refined to a conventional R = 0.057. The coordination around rhodium is distorted square planar and that around iridium is distorted octahedral. The Rh-Ir distance is 2.903 (1) A, and the bridging chlorine atom is almost symmetrically bonded to the metals (Rh-Cl = 2.386 (3), Ir-CI = 2.381 (3) A). The isoelectronic complex [(diph~s)Rh(p-H)(p-Cl)IrH(PEt,)~]BF~ was obtained in a similar reaction, starting from mer,~is-IrH~Cl(PEt,)~. Its structure determined by X-ray diffraction, as above, is monoclinic, space group P21, Z = 2, a = 11.102 (2) A, b = 13.582 (3) A, c = 16.694 (4) A, @ = 85.06 (2)'. The final agreement factor (for the 4553 observed reflections) R is 0.062. As for compound 3 the coordination around Rh and Ir is distorted square planar and octahedral, respectively. There is a pronounced asymmetry in the chlorine bridge (Rh-Cl = 2.394 (5), Ir-Cl = 2.510 (5) A), and the metal-metal separation is 2.969 (2) A. t o the synthesis of cationic Rh(1)-Ir(II1) complexes. Experimental Section All operations were carried out under purified nitrogen. Solvents were distilled under nitrogen and dried prior to use. Elemental analyses were formed by the Microanalytical Section of the Swiss Federal Institute of Technology. Infrared spectra in the region 4000-400 cm-' were recorded on a Beckman IR 4250 spectrophotometer as KBr pellets or Nujol mulls. The IH and 31P{'HJ NMR spectra were recorded at 90.00 and/or 250.00 and 36.43 MHz, respectively, on a FT Bruker WH-90 or F T Bruker 250 instrument. 'H and chemical shifts are given relative to external (CH3)$i and H3P04, respectively. A positive sign denotes a shift downfield of the reference. A. Syntheses. [Rh(dipho~)(nbd)]BF,~ (nbd = norbornadiene), mer,truns-IrHCl2L3 (L = PMe2Ph, PEt2Ph, PEt3),9 and mer,cis-IrHCl2(PMePh2),,Io were prepared according to literature methods. For the preparation of mer,cis-IrH,CI(PEt,),, a toluene solution of [ (~o c)~I r C l ]~ (coc = cyclooctadiene) was reacted with 3 equiv of PEt,, and hydrogen was bubbled through the solution for 10 min, leading almost quantitatively to the product. (a) ETH-Zcntrum. (b) Taken in Dart from the Ph.D. thesis of H.L. (c)
Synthesis and X-ray structures of cyclometalated iridium complexes including the hydrides
Dalton Trans., 2013
Cyclometalation of [Cp*IrCl 2 ] 2 with ketimine ligands generated very active catalysts for transfer hydrogenation of imines as well as reductive amination. The synthesis and X-ray diffraction structures of three such complexes are disclosed in this paper. The hydrides of two complexes, key intermediates in hydrogenation, have been isolated and their structures determined by X-ray diffraction as well.
Organometallics, 1999
The trisacetonitrile complexes [IrClH(P i Pr 3 )(NCCH 3 ) 3 ]BF 4 (1) and [IrH 2 (P i Pr 3 )(NCCH 3 ) 3 ]-BF 4 (2) have been prepared in one-pot reactions with high yields by reaction of the iridium-(I) dimers [Ir(µ-Cl)(coe) 2 ] 2 and [Ir(µ-OMe)(cod) 2 ] 2 with the phosphonium salt [HP i Pr 3 ]BF 4 . The rates of exchange between free acetonitrile and the labile acetonitrile ligands of complexes 1 and 2 have been measured by NMR spectroscopy. This kinetic study has shown that both complexes readily dissociate one acetonitrile ligand trans to hydride, giving rise to fluxional five-coordinate intermediates. Substitution products 3-7 have been obtained by treatment of complexes 1 and 2 with CO and PMe 3 . The structures determined for 3-7 can be rationalized on the basis of the steric requirements of the ligands, indicating that the products are formed by thermodynamic control. Ethene inserts reversibly into the Ir-H bond of 1 to give the compound [IrCl(Et)(P i Pr 3 )(NCCH 3 ) 3 ]BF 4 (8), which has been used for the preparation of the stable ethyliridium(III) complexes [IrCl(Et)(P i Pr 3 )(Py) 2 (NCCH 3 )]BF 4 (9) and [Ir(η 2 -O 2 CCH 3 )Cl(Et)(P i Pr 3 )(NCCH 3 ) 3 ] (10), respectively. The molecular structure of 10 has been determined by X-ray crystallography. The reaction of 2 with ethene, at low temperature, results in the sequential formation of the ethene complex [IrH 2 (
Gold and silver hydrides: synthesis of heterobimetallic iridium-M (M = gold, silver) complexes and x-ray crystal structures of (PPh3)Au(.mu.-H)IrH2(PPh3)3 and (PPh3)Ag(.mu.-H)IrH2(PPh3)3
Inorganic Chemistry, 1989
... Chem. SOC. 1983, 105, 5957. (b) Boyle, PD; Johnson, BJ; Buehler, A,; Pignolet, L. H. Inorg. Chem. ... Chem. 1985,24, 182. (e) Boyle, PD; Johnson, BJ; Alexander, BD; Casalnuovo, J. A,; Gannon, P. R.; Johnson, S. M.; Larka, E. A.; Mueting, A. M.; Pignolet, LH Inorg. Chem. ...
Organometallics
Structural Analysis of Complexes 2, 5, 6, and 7 S3 Computational Details S4 NMR spectra of complexes 2-8 S5 Energies of optimized structures S16 UV-vis spectra of complexes 2, 4, A, and B (observed and calculated) S18 Analysis of computed UV/Vis data for 2, 4, A, and B S20 Frontier molecular orbitals for complexes 2, 4, A, and B S24 Cyclic voltammograms of complexes 2, 4, A, and B S32 Normalized excitation and emission spectra for complexes 2, 4, A, and B S33 Natural transition orbital analysis for T 1 transition of complexes 2, 4, A, and B S37 References S38 S3 Experimental Section: General Information. 1 H, 31 P{ 1 H}, and 13 C{ 1 H} NMR spectra were recorded on Bruker Avance 300 or 400 MHz instrument. C, H, and N analyses were carried out in a Perkin-Elmer 2400 CHNS/O analyzer. High-resolution electrospray mass spectra were acquired using a MicroTOF-Q hybrid quadrupole time-of-flight spectrometer (Bruker Daltonics, Bremen, Germany). UV-visible spectra were registered on an Evolution 600 spectrophotomer. Steady-state photoluminescence spectra were recorded on a Jobin-Yvon Horiba Fluorolog FL-3-11 spectrofluorimeter. Lifetimes were measured using an IBH 5000F coaxial nanosecond flash lamp. Quantum yields were measured using the Hamamatsu Absolute PL Quantum Yield Measurement System C11347-11. Cyclic voltammetry measurements were performed using a Voltalab PST050 potentiostat with Pt wire as working electrode, Pt wire as counter electrode, and saturated calomel (SCE) as reference electrode. The experiments were carried out under argon in dichloromethane (10-3 M) or dichloromethane-acetonitrile (1:1) solutions (5x10-4 M), with Bu 4 NPF 6 as supporting electrolyte (0.1 M). Scan rate was 100 mV•s-1. The potentials were referenced to the ferrocene/ferrocenium (Fc/Fc +) couple. Structural Analysis of Complexes 2, 5, 6, and 7. X-ray data were collected on a Bruker Smart APEX DUO CCD diffractometer equipped with a fine focus, and 2.4 kW sealed tube source (Mo radiation, λ = 0.71073 Å). Data were collected over the complete sphere covering 0.3 o in ω. Data were corrected for absorption by using a multiscan method applied with the SADABS program. 1 The structures were solved by Patterson or direct methods and refined by full-matrix least squares on F 2 with SHELXL2016, 2 including isotropic and subsequently anisotropic displacement parameters. The hydrogen atoms were observed in the last Fourier Maps or calculated, and refined freely or using a restricted riding model. The hydride ligands were located, but in some cases they do not refine properly so distances to iridium were restricted to 1.59(1) Å.