Neutral iridium(III) complexes of the unidentate P-donor ligands dppm, dppmS and dppmSe, and cationic complexes with these ligands acting in their bidentate form have been prepared and characterized. Similar cationic complexes with the symmetrical bidentate dichalcogenide ligands dppmS, and dppmSe, have been described. These compounds react with sodium hydride in tetrahydrofuran or with thallium pyrazolate in dichloromethane to yield the new cationic complexes [(eta(5)C(5)Me(5))Ir{eta(3)(EPPh(2))(2)CH-C,E,E'}](+) (E = S, Se) in which the anionic methanide dichalcogenide ligand is acting as a tripod ligand with a C,E,E'-donor set. However, the complexes [(eta(5)C(5)Me(5))IrCl(eta(2)dppmE(2))]BF4 react with P(OMe)(3) in the presence of TIBF4, to give the dicationic compounds [(eta(5)C(5)Me(5))Ir{P(OMe>(3)}(eta(2)dppmE(2))(BF4)(2). In these complexes, the P(OMe)(3) ligand is transformed into a coordinated PO(OMe)(2) group by reaction with sodium iodide in acetone. The structure of the complex [(eta(5)C(5)Me(5))Ir{PO(OMe)(2)}(eta(2)dppmS(2)-S,S')]BF4 . 0.5Me(2)CO have been determined by single crystal X-ray diffraction methods.
Neutral iridium(III) complexes of the unidentate P-donor ligands dppm, dppmS and dppmSe, and cationic complexes with these ligands acting in their bidentate form have been prepared and characterized. Similar cationic complexes with the symmetrical bidentate dichalcogenide ligands dppmS, and dppmSe, have been described. These compounds react with sodium hydride in tetrahydrofuran or with thallium pyrazolate in dichloromethane to yield the new cationic complexes [(eta(5)C(5)Me(5))Ir{eta(3)(EPPh(2))(2)CH-C,E,E'}](+) (E = S, Se) in which the anionic methanide dichalcogenide ligand is acting as a tripod ligand with a C,E,E'-donor set. However, the complexes [(eta(5)C(5)Me(5))IrCl(eta(2)dppmE(2))]BF4 react with P(OMe)(3) in the presence of TIBF4, to give the dicationic compounds [(eta(5)C(5)Me(5))Ir{P(OMe>(3)}(eta(2)dppmE(2))(BF4)(2). In these complexes, the P(OMe)(3) ligand is transformed into a coordinated PO(OMe)(2) group by reaction with sodium iodide in acetone. The structure of the complex [(eta(5)C(5)Me(5))Ir{PO(OMe)(2)}(eta(2)dppmS(2)-S,S')]BF4 . 0.5Me(2)CO have been determined by single crystal X-ray diffraction methods.
Reactions of a unidentate bis(diphenylphosphino)methane (dppm) complex Cp*IrCl2(eta (1)-dppm) (1) with 2 equiv of NaOR (R = Et, Me, or Pr-i) give ring-methyl-alkoxylated complexes (C5Me4CH2OR)Ir(eta (2)-dppm) [R = Et (5a); R = Me (5b); R = Pr-i (5c)], respectively. Cationic complexes [Cp*IrCl(eta (2)-dppm)]OTf (2), [Cp*IrClP(OPh)(3)}(2)]OTf(3), and [Cp*IrCl(PPh3)(2)]OTf (4) react with 2 equiv of NaOEt to give (C5Me4CH2OEt)IrL2 [L-2 = dppm (5a); L = P(OPh)(3) (6a); L = PPh3 (7a)], respectively. The complex 3 reacts with 2 equiv of (NaOBu)-Bu-t in ethanol, methanol, 2-propanol, allyl alcohol, or propargyl alcohol to give (C5Me4CH2OR)Ir(P(OPh)3)2 [R = Et (6a); R = Me (6b); R = Pr-i (6c) R = allyl (6d); R = propargyl (6e)], respectively. Furthermore, treatment of 3 with 2 equiv of (BuLi)-Bu-n and excess diethylamine, propylamine, N-methylaniline, or aniline in triethylamine as solvent gives ring-methyl aminated complexes ((C5Me4CH2NRR2)-R-1)Ir(P(OPh)(3))(2) [R-1 = R-2 = Et (8a); R-1 = Pr-n, R-2 = H (sb); R-1 = Ph, R-2 = Me (8c); R-1 = Ph, R-2, H (8d)], respectively. The structure of 8a has been confirmed by X-ray analysis.
Synthesis and Properties of Compressed Dihydride Complexes of Iridium: Theoretical and Spectroscopic Investigations
作者:Ricard Gelabert、Miquel Moreno、José M. Lluch、Agustí Lledós、Vincent Pons、D. Michael Heinekey
DOI:10.1021/ja048775l
日期:2004.7.1
Reaction of [Cp*Ir(P-P)Cl][B(C6F5)(4)] (P-P = bisdimethydiphosphinomethane (dmpm), bisdiphenyldiphosphinomethane (dppm)) with [Et3Si][B(C6F5)(4)] in methylene chloride under 1 atm of hydrogen gas affords the dicationic compressed dihydride complexes [Cp*Ir(P-P)H-2][B(C6F5)(4)](2). These dicationic complexes are highly acidic and are very readily deprotonated to the corresponding monohydride cations. When the preparative reaction is carried out under HD gas, the hydride resonance exhibits J(HD) = 7-9 Hz, depending upon the temperature of observation, with higher values of J(HD) observed at higher temperatures. A thermally labile rhodium analogue, [Cp*Rh(dmpm)(H-2)][B(C6F5)(4)](2), was prepared similarly. A sample prepared with HD gas gave J(HD) = 31 Hz and J(HRh) = 31 Hz, allowing the Rh complex to be identified as a dihydrogen complex. Quantum dynamics calculations on a density functional theory (DFT) potential energy surface have been used to explore the structure of the Ir complexes, with particular emphasis on the nature of the potential energy surface governing the interaction between the two hydride ligands and the Ir center.