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Issue 17, 1998
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Synthesis and reactions of ene–hydrazone diphosphine iridium complexes and related species

Abstract

Treatment of the azine diphosphine Z,Z-PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(But)CH2PPh2 I with [IrCl(CO)2(H2NC6H4Me-4)] in benzene gave the ene–hydrazone diphosphine iridium(III) hydride [IrH(Cl)(CO){PPh2CH[double bond, length half m-dash]C(But)N–N[double bond, length half m-dash]C(But)CH2PPh2}], 1, which isomerised reversibly to the ionic square planar iridium(I) complex [Ir(CO){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(But)CH2PPh2}]Cl 2a, containing an azine diphosphine. Treatment of 1 with NEt3 gave the neutral ene–hydrazone diphosphine iridium(I) complex [Ir(CO){PPh2CH[double bond, length half m-dash]C(But)N–N[double bond, length half m-dash]C(But)CH2PPh2}] 3 which is reactive and undergoes oxidative addition of H2 to give the iridium(III) dihydride mer,cis-[IrH2(CO){PPh2CH[double bond, length half m-dash] C(But)N–N[double bond, length half m-dash]C(But)CH2PPh2}] 4 and oxidative addition of MeI to give the methyliridium(III) complex [IrMe(I)(CO){PPh2CH[double bond, length half m-dash]C(But)N–N[double bond, length half m-dash]C(But)CH2PPh2}] 5. It reacted rapidly with olefins or acetylenes (L), i.e.N-methylmaleimide, ethene or dimethyl acetylenedicarboxylate, to give the five-co-ordinate adducts [Ir(CO)L{PPh2CH[double bond, length half m-dash] C(But)N–N[double bond, length half m-dash]C(But)CH2PPh2}], 6a, 6b or 6c, respectively, also with O2 to give the η2-dioxygen adduct [Ir(CO)(η2-O2){PPh2CH[double bond, length half m-dash]C(But)N–N[double bond, length half m-dash]C(But)CH2PPh2}] 7. Treatment of 3 with 1 mol of picric acid protonated the ene–hydrazone diphosphine backbone to give the azine diphosphine iridium(I) salt [Ir(CO){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash] C(But)CH2PPh2}][OC6H2(NO2)3] 2b. The N-methylmaleimide adduct 6a was similarly protonated to give the corresponding azine diphosphine iridium(I) salt [Ir(CO)(η2-COCH[double bond, length half m-dash]CHCONMe){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(But)CH2PPh2}][OC6H2(NO2)3] 8. Complex 1 was protonated by HCl to give the corresponding azine diphosphine iridium(III) salt [IrH(Cl)(CO){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(But)CH2PPh2}]Cl 9a, which is converted into 3 when treated with NEt3. The 1H, 13C and 31P NMR and some IR data are given.

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Article type: Paper
DOI: 10.1039/A802073F
J. Chem. Soc., Dalton Trans., 1998, 2887-2892

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    Synthesis and reactions of ene–hydrazone diphosphine iridium complexes and related species

    S. D. Perera and B. L. Shaw, J. Chem. Soc., Dalton Trans., 1998, 2887
    DOI: 10.1039/A802073F

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