8-Oxyquinolate iridium(I) complexes and their oxidative-addition reactions (original) (raw)
1981, Journal of Organometallic Chemistry
(diphenylphosphino)ethane or c&1,2-bis(diphenylphosphino)ethylene)_ Carbon monoxide displaces the COD group from the complexes giving either CMOq)(COM or CWOq)WO)LI, and the latter undergo osidative addition reactions with SnCl,, Me,SiCl, Me,SnCl, MeI, allylbromide, PhCOCl, MeCOCl, Cl,, Brz, TlCl, and HCl leading to novel iridium(II1) complexes.
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Structure and Reactivity of New Iridium Complexes with Bis(Oxazoline)-Phosphonito Ligands
Inorganic Chemistry, 2009
The synthesis and characterization of novel iridium(I) complexes bearing a neutral bis(oxazoline)phosphonite ligand, NOPON Me 2 (I), are reported. Numerous Ir(I) complexes have been isolated in high yields and characterized by spectroscopy and X-ray diffraction. [Ir(μ-Cl)(cod)] 2 (cod = 1,5-cyclooctadiene) reacted with I to give the air-sensitive complex [IrCl(cod)(NOPON Me 2 )] (1), which shows broad 1 H and 13 C{ 1 H} NMR signals due to dynamic exchange equilibria involving the cod and the NOPON Me 2 ligands. Reaction between a solution of 1 and CO afforded the carbonyl complex [IrCl(CO)(NOPON Me 2 )] (2), whose solid-state structure has been determined by X-ray diffraction. Cationic complexes have been obtained by using NaBAr F (BAr F = B[3,5-(CF 3 ) 2 C 6 H 3 ] 4 ) as a chloride abstractor. The complex [Ir(cod)(NOPON Me 2 )]BAr F (3) displays a mononuclear structure in the solid state with ligand I acting as a bidentate P,N chelating ligand. This complex is a precatalyst for the hydrogenation of alkenes. Oxidative addition of H 2 to 3 occurred either in solution or in the solid-state and this reaction allowed the isolation of the 32 electron, dinuclear dihydridobridged iridium(III) complex [IrH(μ-H)(NOPON Me 2 )] 2 (BAr F ) 2 (4), in which the NOPON Me 2 ligands exhibit a facial coordination mode. It contains only hydrides as bridging ligands and the Ir 2 (μ-H) 2 unit can be viewed as containing a formal Ir-Ir double bond or two 3c-2e bonds. Complex 3 has also been reacted with CO in solution and in the solid state, and this yielded the dicarbonyl derivative [Ir(CO) 2 (NOPON Me 2 )]BAr F (5). A transmetalation reaction between 3 and [PdCl 2 (NCPh) 2 ] afforded the cationic Pd(II) complex [PdCl(NOPON Me 2 )]BAr F (6), which has been structurally characterized.
Preparation of Phosphorescent Iridium(III) Complexes with a Dianionic C,C,C,C-Tetradentate Ligand
Inorganic chemistry, 2018
The preparation and photophysical properties of heteroleptic iridium(III) complexes containing a dianionic C,C,C,C-tetradentate ligand and a cyclometalated phenylpyridine group are described. Complex [Ir(μ-OMe)(COD)](1, COD = 1,5-cyclooctadiene) reacts with 1,1-diphenyl-3,3-butylenediimidazolium iodide ([PhIm(CH)ImPh]I), in the presence NaOBu, to give [Ir(μ-I){κ- C, C, C, C-[CHIm(CH)ImCH]}](2), which leads to {[Ir{κ- C, C, C, C-[CHIm(CH)ImCH]}](μ-OH)(μ-OMe)} (3) by treatment first with silver trifluoromethanesulfonate (AgOTf) in acetone-dichloromethane and subsequently with KOH in methanol. The reaction of 2 with AgOTf and acetonitrile affords the bis(solvento) complex [Ir{κ- C, C, C, C-[CHIm(CH)ImCH]}(CHCN)]OTf (4). The latter promotes the pyridyl-supported heterolytic ortho-CH bond activation of the phenyl group of 2-phenylpyridine, 2-(2,4-difluorophenyl)pyridine, 2-( p-tolyl)pyridine, and 5-methyl-2-phenylpyridine to yield Ir{κ- C, C, C, C-[CHIm(CH)ImCH]}{κ- C, N-[Ar-py]} (Ar-py ...
RSC Advances, 2021
Two iridium(III) complexes were isolated via the reaction of pyridine-2-aldoxime (Hpyrald) with 7,8benzoquinoline (benzq)-derived iridium starting material, namely [(benzq) 2 Ir(m-Cl) 2 Ir(benzq) 2 ] (1). Among the two complexes, [Ir III (benzq) 2 (pyrald)] (2) and [Ir III (benzq-kN,kC 10)(benzq-kC 2)(Hpyrald)(Cl)] (3), the later displayed unusual ortho C-H bond activation in one of the coordinated 7,8-benzoquinoline rings. The complex (2) presented a usual structure as expected. C-H bond activation has long been explored fruitfully in the formation of carbon-carbon 1,2 and metal-carbon 3,4 bonds during the synthesis of fascinating organic compounds and organometallic complexes. The C-H bond, though inert in nature, can be activated through the catalytic power of different metal-based catalysts. 1,3 Among the several catalysts designed and synthesised so far, the platinum group metal-derived catalysts are well-known for their facile C-H bond activation in a vast range of organic molecules. 3 A judicious choice of organic ligands in metal complex preparation and C-H bond activation therein could lead to the metal-carbon bond formation. The cyclometallating ligand, such as phenyl pyridine (ppy), is one such class of ligand, which binds the metal through pyridine-N and a benzene ring-C (kN, kC 8) in the cyclometallated way (Fig. 1; complex (4)) involving the C-H bond activation by the coordinated metal ions. 3 Iridium is well known for its cyclometallating properties, which causes C-H bond
Organometallics, 2006
Treatment of [Ir(µ-Cl)(COE) 2 ] 2 (1) with LiCp O gives Ir(η 5-Cp O)(COE) 2 (2; Cp O) C 5 H 4 (CH 2) 2 OCH 3 , COE) cis-cyclooctene), which reacts with X 2 to afford the iridium(III) derivatives [Ir(η 5-Cp O)X(µ-X)] 2 (X) I (3), Cl (4)). Complexes 3 and 4 react with P i Pr 3 to yield the corresponding species Ir(η 5-Cp O)(P i-Pr 3)X 2 (X) I (5), Cl (6)), which by addition of LiHBEt 3 give Ir(η 5-Cp O)(P i Pr 3)H 2 (7). The reactions of 5 and 6 with 2.0 equiv of AgBF 4 in acetonitrile lead to [Ir(η 5-Cp O)(P i Pr 3)(NCMe) 2 ][BF 4 ] 2 (8). Treatment of 3 with 2.0 equiv of HSiEt 3 per iridium affords the monohydride dimer [Ir(η 5-Cp O)I] 2 (µ-H)(µ-I) (9). Complex 4 reacts with 4.0 equiv of HSiEt 3 per iridium to give the iridium(V) silyl trihydride derivative IrH 3 (η 5-Cp O)(SiEt 3) (10), which in the presence of excess of HSiEt 3 is transformed into IrH 2 (η 5-Cp O)-(SiEt 3) 2 (11). Treatment at-40°C of 4 with 2.0 equiv of HSiEt 3 per iridium leads to a mixture of the hydride dichloro triethylsilyl complex IrH(η 5-Cp O)Cl 2 (SiEt 3) (12), the dihydride chloro triethylsilyl compound IrH 2 (η 5-Cp O)Cl(SiEt 3) (14), and the monohydride dimer [Ir(η 5-Cp O)Cl] 2 (µ-H)(µ-Cl) (16). Complex 16 has been also prepared by reaction of 4 with 1.0 equiv of HSiEt 3 per iridium. Complex 10 is easily deuterated in C 6 D 6 at 80°C. The X-ray structures of 4, 8, and 9 are also reported.
Iridium(I) and Iridium(III) Complexes Supported by a Diphenolate Imidazolyl-Carbene Ligand
Organometallics, 2010
Deprotonation of 1,3-di(2-hydroxy-5-tert-butylphenyl)imidazolium chloride (1a) followed by reaction with chloro-1,5-cyclooctadiene Ir(I) dimer affords the anionic Ir(I) complex [K][{OCO}Ir(cod)] (2: OCO = 1,3-di(2-hydroxy-5-tert-butylphenyl)imidazolyl; cod = 1,5-cyclooctadiene), the first Ir complex stabilized by a diphenolate imidazolyl-carbene ligand. In the solid state 2 exhibits squareplanar geometry, with only one of the phenoxides bound to the metal center. Oxidation of 2 with 2 equiv of [FeCp 2 ][PF 6 ] generates the Ir(III) complex [{OCO}Ir(cod)(MeCN)][PF 6 ] (3). Reaction of 3 with H 2 results in the liberation of cyclooctane and a species capable of catalyzing the hydrogenation of cyclohexene to cyclohexane. Displacement of cyclooctadiene from 3 can be achieved by heating in acetonitrile to form [{OCO}Ir(MeCN) 3 ][PF 6 ] (4) or by reaction with either PMe 3 or PCy 3 to generate [{OCO}Ir(PMe 3 ) 3 ][PF 6 ] (5) or [{OCO}Ir(PCy 3 ) 2 (MeCN)][PF 6 ] (6), respectively. 6 reacts with CO in acetonitrile to give an equilibrium mixture of 6 and [{OCO}Ir(PCy 3 ) 2 (CO)][PF 6 ] (7) and with chloride to generate [{OCO}Ir(PCy 3 ) 2 Cl] . The solid-state structure of 8 shows that the diphenolate imidazolylcarbene ligand is distorted from planarity; DFT calculations suggest this is due to an antibonding interaction between the phenolates and the metal center in the highest occupied molecular orbital (HOMO) of the complex. 8 undergoes two successive reversible one-electron oxidations in CH 2 Cl 2 at -0.22 and at 0.58 V (vs ferrocene/ferrocenium); EPR spectra, mass spectroscopy, and DFT calculations suggest that the product of the first oxidation is [{OCO}Ir(PCy 3 ) 2 Cl] þ (8 þ ), with the unpaired electron occupying a molecular orbital that is delocalized over both the metal center and the diphenolate imidazolyl-carbene ligand.
Polyhedron, 1987
The complexes M(l-nqo), (M = Rh or Ir, 1-nqoH = 1,Znaphthoquinone 1-oxime) and M(2-nqo), (M = Rh or Ir, 2-nqoH = 1,Znaphthoquinone 2-oxime) were prepared by the interaction of the quinone oxime with hydrated rhodium(II1) chloride or chloroiridic(II1) acid. The mixture resulting from the reaction of chloroiridic(II1) acid and 1 ,Znaphthoquinone I-oxime on treatment with pyridine afforded [pyH]pr(l-nqo) (py)Cl,] which was characterized by X-ray crystallography. The complexes Rh(l-nqo), and Rh(2-nqo)3 were also obtained by the nitrosation of the respective naphthol in the presence of hydrated rhodium(II1) chloride. None of the trischelates showed any tendency to react with pyridine, triphenylphosphine or aqueous hydrochloric acid.
Dalton Transactions, 2011
The synthesis of a new family of octahedral Ir(III) complexes with dual cyclometalating phosphine chelates, namely: 1-(diphenylphosphino)naphthalene (dpnaH) and isoquinoline (dppiH), is reported. Two series of intermediate complexes, [Ir(dpna)(tht) 2 Cl 2 ] (1), [Ir(dpna) 2 (OAc)] (2), [Ir(dppiH)(dppi)Cl 2 ] (3) and [Ir(dppi) 2 (OAc)] (4), which can be classified by the coexistence of either a pair of cis-chlorides or a single acetate chelate, were obtained from treatment of phosphine with [IrCl 3 (tht) 3 ] (tht = tetrahydrothiophene). The in situ generated acetate complexes 2 and 4 could react with azolate chelates, namely: 5-(2-pyridyl)-3-trifluoromethyl pyrazole (fppzH) and 5-(1-isoquinolyl)-3-tert-butyl-1,2,4-triazole (iqbtzH), to afford a new series of luminescent complexes [Ir(dpna) 2 (fppz)] (5a and 5b), [Ir(dpna) 2 (iqbtz)] (6a and 6b), [Ir(dppi) 2 (fppz)] (7a) and [Ir(dppi) 2 (iqbtz)] (8a). The phosphorescence lifetime (t obs ) fell in the range of a few tens of ms, showing possession of excessive ligand-centered pp* mixed in part with MLCT character. A density functional theory (DFT) study was also conducted in order to shed light on the origin of the transitions in the absorption and emission spectra and to predict emission energies for these complexes. Organic light emitting diodes (OLEDs) displaying bright orange emission and with maximum h ext up to 17.1% were fabricated employing complexes 6a and 8a as the phosphorescent dopants.
Inorganic Chemistry, 2012
The reaction of the cyclometalated chloro-bridged iridium(III) dimers [(ppy) 2 Ir(μ-Cl)] 2 (ppyH = 2-phenyl pyridine) and [(tpy) 2 Ir(μ-Cl)] 2 (tpyH = 2-p-tolylpyridine) with 3,5-diphenylpyrazole (Ph 2 PzH) in the presence of sodium methoxide resulted in the formation of heterobridged dimers [(ppy) 2 Ir(μ-OH)(μ-Ph 2 Pz)Ir(ppy) 2 ] (1) and [(tpy) 2 Ir(μ-OH)(μ-Ph 2 Pz)Ir(tpy) 2 ] (2). Interestingly, the reaction of [(ppy) 2 Ir(μ-Cl)] 2 with 3(5)-methyl-5(3)-phenylpyrazole (PhMePzH) afforded both a heterobridged dimer, [(ppy) 2 Ir(μ-OH)(μ-PhMePz)Ir(ppy) 2 ] (3), and the monomer [(ppy) 2 Ir-(PhMePz)Cl] (4). The compound [(ppy) 2 Ir(PhMePz)OH] (5) containing a terminal OH was obtained in a hydrolysis reaction involving 4, sodium methoxide, and PhMePzH. Complexes 1−5 were characterized by X-ray crystallography and electrospray ionization high-resolution mass spectrometry. All of the complexes are luminescent at room temperature in their dichloromethane solutions. The luminescence of the dinuclear complexes is characterized by a single structureless band centered at λ max = 550 nm (1 and 3) and 546 nm (2). The emission spectra of the mononuclear complexes 4 and 5 display vibronic structures with their λ max values at 497 nm (4) and 513 nm (5). In each case, the main emission bands are accompanied by shoulder bands at 526 (4) and 534 nm (5). The quantum yields, calculated with reference to [Ir(ppy) 2 (bpy)]PF 6 (Φ CH 3 CN = 0.0622), range from 0.11 to 0.17 for the dinuclear complexes and 0.045 to 0.048 for the mononuclear complexes. The lifetimes of the emission are in the microsecond region, suggesting the phosphorescent nature of the emission. Density functional theory (DFT) and time-dependent DFT calculations were performed on complexes 1 and 4 in the ground state to gain insight into the structural, electronic, and photophysical properties. Electrochemical studies on complexes 1−3 showed the presence of two consecutive one-electron-oxidation processes, assigned as the stepwise oxidation of the two Ir III centers, i.e., Ir III −Ir III /Ir III −Ir IV and Ir III −Ir IV /Ir IV −Ir IV couples, respectively. The monomers displayed singleoxidation peaks. No reduction process was observed within the solvent cathodic potential limit.