Hydride complexes IrHCl2[PPh(OEt)2]L21, 3 and IrHCl2[P(OEt)3]L22, 4 (L = PPh3 or AsPh3) were prepared by substituting one phosphine or arsine ligand in IrHCl2L3 with the appropriate phosphite. Treatment of hydrides 1–4 first with triflic acid (CF3SO3H) and then with hydrazines gave [IrCl2(RNHNH2)PPh(OEt)2}L2]BPh45, 7 and [IrCl2(RNHNH2)P(OEt)3}L2]BPh46, 8 (R = H, Me, Ph or C6H4NO2-4). Hydride–hydrazine complexes [IrH2(RNHNH2)(PPh3)3]BPh49 and [IrHCl(RNHNH2)(PPh3)2]BPh410 (R = H, Me or Ph) were also prepared by allowing IrH3(PPh3)3 or IrH2Cl(PPh3)3 to react sequentially first with CF3SO3H or HBF4·Et2O and then with the appropriate hydrazine. All complexes were fully characterised by IR and NMR spectroscopy and their geometry in solution was also established. Oxidation with Pb(OAc)4 at −30 °C of arylhydrazines [IrCl2(ArNHNH2)L′L2]BPh45–8 [L′ = PPh(OEt)2 or P(OEt)3; Ar = Ph] afforded stable aryldiazene derivatives [IrCl2(ArNNH)PPh(OEt)2}L2]BPh411, 13 and [IrCl2(ArNNH)P(OEt)3}L2]BPh412, 14. By contrast, treatment with Pb(OAc)4 at −30 °C of methylhydrazine complexes [IrCl2(MeNHNH2)L′L2]BPh4 gave hydrides IrHCl2L′L2. Aryldiazene complexes [IrCl2(ArNNH)L′L2]BPh411–14 and [IrCl2L′L2}2(μ-HNNAr–ArNNH)](BPh4)215–18 [Ar = Ph or C6H4Me-4; Ar–Ar = 4,4′-C6H4–C6H4 or 4,4′-(2-Me)C6H3–C6H3(Me-2)] were also prepared by allowing hydride species IrHCl2L′L21–4 to react with the appropriate aryldiazonium cations in acetone at −80 °C. Their characterisation by IR and NMR spectroscopy (with 15N isotopic substitution) is discussed.
Pyrazole IrHCl2(HRpz)P2 [P = PPh3, PiPr3; R = H, 3-Me], bis(pyrazole) [IrHCl(HRpz)2(PPh3)2]BPh4 and imidazole IrHCl2(HIm)(PPh3)2 derivatives were prepared by allowing the IrHCl2(PPh3)3 complex to react with the appropriate azole in refluxing 1,2-dichloroethane. Nitrile IrHCl2(CH3CN)(PPh3)2 and 2,2′-bipyridine (bpy) [IrHCl(bpy)(PPh3)2]BPh4 derivatives were also prepared using IrHCl2(PPh3)3 as a precursor
Synthesis of a heterobimetallic dihydride by the addition of a rhenium dihydride to a platinum(0) complex
作者:Charles P. Casey、Edward W. Rutter、Kenneth J. Haller
DOI:10.1021/ja00256a071
日期:1987.10
The authors have been searching for routes to heterobimetallic dihydrides since they anticipate that such compounds might be unusual reducing agents. Here they report the synthesis of a heterobimetallic dihydride by oxidative addition of a metal dihydride to a second metal center. The thermodynamic driving force for the process is the formation of a new metal-metal bond.
Strong <sup>31</sup>P nuclear spin hyperpolarization produced via reversible chemical interaction with parahydrogen
作者:Vladimir V. Zhivonitko、Ivan V. Skovpin、Igor V. Koptyug
DOI:10.1039/c4cc08115c
日期:——
The reversible interaction of the (PPh3)3Ir(H2)Cl complex with parahydrogen led to strong 31P nuclear hyperpolarization of free and bound PPh3 species, which was employed to perform single-shot 31P MRI.