Dihydridobis(Solvent)Bis(Triphenylphosphine)Iridium(III) Tetrafluoroborates

Crabtree, Robert H.; Mellea, Michelle F.; Mihelcic, Jean M.; Sen, Ayusman; Chebolu, Venkatasuryanarayana

doi:10.1002/9780470132579.ch22

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Tri(phenyl)phosphine (Aldrich), tri( p -tolyl)phosphine (Strem), tri(anisolyl)phosphine (Strem), pyridine (Aldrich), and 15 N-pyridine (Cambridge Isotopes) were used as supplied and stored under N 2 . [Ir(COD)(PPh 3 ) 2 ]BF 4 ( 1a ) and [Ir(COD)(NCMe) 2 ]BF 4 were prepared by literature methods. ,,, …”

Section: Methodsmentioning

confidence: 99%

“…[Ir(COD)(PPh 3 ) 2 ]BF 4 (1a) and [Ir(COD)(NCMe) 2 ]BF 4 were prepared by literature methods. 26,29,36,37 [Ir(COD)(P{p-tolyl} 3 ) 2 ]BF 4 (1b). The known complex 1b was prepared as follows: [Ir(COD)(NCMe) 2 ]BF 4 (150 mg, 0.32 mmol) was dissolved in dichloromethane (5 mL) to which was added by canula P(p-tolyl) 3 (195 mg, 0.64 mmol) in dichloromethane (5 mL).…”

Section: Methodsmentioning

confidence: 99%

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Para-Hydrogen Induced Polarization without Incorporation ofPara-Hydrogen into the Analyte

et al. 2008

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The cationic iridium complexes [Ir(COD)(PR3)2]BF4 (1a-c) (a, R = Ph; b, R = p-tolyl; c, R = p-C6H4-OMe) react with parahydrogen in the presence of pyridine to give trans, cis, cis-[Ir(PR3)2(py)2(H)2]+ (2a-c) and small amounts of fac, cis-[Ir(PR3)(py)3(H)2]+ (3a-c), each of which exhibit polarized hydride resonances due to the magnetic inequivalence associated with the resultant AA"XX" spin system when 15N-labeled pyridine is employed. The pyridine ligands in 2 are labile, exchanging slowly into free pyridine with a rate constant of 0.4 s(-1) for 2a at 335 K in a dissociative process where DeltaH(double dagger) = 134 +/- 1 kJ mol(-1) and DeltaS(double dagger) = 151 +/- 5 J mol(-1) K(-1). Pyridine ligand exchange in 2 proves to be slower than that determined for 3. Parahydrogen induced polarization (PHIP) based on the hydride ligands of 2 and 3 is transferred efficiently to the 15N nuclei of the bound pyridine ligand by suitable insensitive-nuclei-enhanced-by-polarization-transfer (INEPT) based procedures. Related methods are then used to facilitate the sensitization of the free pyridine 15N signal by a factor of 120-fold through ligand exchange even though this substrate does not contain parahydrogen. This therefore corresponds to the successful polarization of an analyte by parahydrogen induced polarization methods without the need for the actual chemical incorporation of any parahydrogen derived nuclei into it.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Para-Hydrogen Induced Polarization without Incorporation ofPara-Hydrogen into the Analyte

et al. 2008

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“…The observation of the hydride resonance at ca. d À16 ppm suggests that the hydride is trans to the pyridyl instead of the phenyl group [13]. An attempt to prepare a trimetallic porphyrin complex by reaction of Ni(H 2 P 2 ) with two equivalent of [Ir(H) 2 (PPh 3 ) 2 (Me 2 CO) 2 ][BF 4 ] was not successful.…”

Section: Synthesismentioning

confidence: 97%

“…Elemental analyses were performed by Medac Ltd., UK. Benzenedipyrromethane, 4-methylbenzenedipyrromethane [12], and [Ir(H) 2 (PPh 3 ) 2 (Me 2 CO) 2 ][BF 4 ] [13] were prepared according to literature methods. 4-(2 0 -Pyridyl)benzaldehyde was purchased from Aldrich Ltd.…”

Section: General Informationmentioning

confidence: 99%

Bimetallic complexes with porphyrins containing a cyclometalated phenylpyridine group

Cheung

Zhang

Mak

et al. 2005

Journal of Organometallic Chemistry

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Synthesis and Catalytic Applications of Chiral Hydridoiridium(III) Complexes with Diamine/Bis(monophosphane) and Diamine/Diphosphane Coordination

2007

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The P2/N2‐coordinated cis‐dihydridoiridium(III) chelate complexes (OC‐6‐13)‐[IrH2(H2N∩NH2)(PR3)2]BF4 [PR3 = PPh3, H2N∩NH2 = 1,2‐(H2N)2C6H4 (1a); (1R,2R)‐(H2N)2C6H10 {(R,R)‐dach} (1b); (R)‐2,2′‐diamino‐1,1′‐binaphthyl {(R)‐dabin} (1c); PR3 = PiPr3, H2N∩NH2 = (R,R)‐dach (2a), (R)‐dabin (2b); PR3 = PCy3, H2N∩NH2 = (R)‐dabin (3)] were obtained by treating the respective diamine ligands with labile precursors such as [IrH2(OCMe2)2(PPh3)2]BF4, [(η4‐1,5‐C8H12)Ir(PPh3)2]BF4, or [IrH5(PR3)2]/HBF4 (R = iPr, Cy). While oxidative addition of HCl to [(η4‐1,5‐C8H12)Ir{(S,S)‐bdpcp}]BF4 [(S,S)‐bdpcp = (1S,2S)‐(Ph2P)2C5H8] yields the usual mononuclear adduct [(η4‐1,5‐C8H12)Ir(H)(Cl){(S,S)‐bdpcp}]BF4 (4), similar treatment of [(η4‐1,5‐C8H12)Ir{(R)‐binap}]BF4 furnishes the triply chlorido‐bridged diiridium complex [{(R)‐binap}2Ir2H2(μ‐Cl)3]BF4 (5). Opening of the μ‐Cl bridges of 5 by N,N nucleophiles was used to synthesise the three diamine/(R)‐binap complexes [Ir(H)(Cl)(H2N∩NH2){(R)‐binap}]BF4 [H2N∩NH2 = (1R,2R)‐H2NCH(Ph)CH(Ph)NH2 {(R,R)‐dpen} (6a), (R,R)‐dach (6b), and H2NCMe2CMe2NH2 {tmen} (6c). Whereas the dihydrides [IrH2{(R,R)‐dach}(PR3)2]BF4 and [IrH2{(R)‐dabin}(PR3)2]BF4 (R = iPr, Ph) are only poor (pre)catalysts for the enantioselective hydrogenation of acetophenone, complexes 6a–c catalyze the formation of 1‐phenylethanol in good enantiomeric excess [eemax = 82–84 % (S)] in the presence of base. The crystal structures of 1a, 4, and 5 have been determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Dihydridobis(Solvent)Bis(Triphenylphosphine)Iridium(III) Tetrafluoroborates

Cited by 5 publications

References 10 publications

Para-Hydrogen Induced Polarization without Incorporation ofPara-Hydrogen into the Analyte

Para-Hydrogen Induced Polarization without Incorporation ofPara-Hydrogen into the Analyte

Bimetallic complexes with porphyrins containing a cyclometalated phenylpyridine group

Synthesis and Catalytic Applications of Chiral Hydridoiridium(III) Complexes with Diamine/Bis(monophosphane) and Diamine/Diphosphane Coordination

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