- Unusual behavior in the 308 nm flash photolysis of Vaska's complex
-
Time-resolved IR absorption spectroscopy was used to investigate the photolysis of Vaska's Complex (VC), trans-(PPh3)2 Ir(CO)(Cl). Upon 308 nm photolysis, an intermediate was formed that regenerated VC on a millisecond timescale. This intermediate was not formed at the laser flash, but was generated over the course of ~10 μs. Most unusually, there was no evidence for prompt bleach of the C-O stretch of VC upon photolysis. Evidence was presented that the intermediate from which regeneration of VC occurred was a dimeric species. Possible pathways for the generation of the dimeric intermediate are discussed.
- Schultz, Richard H.
-
-
Read Online
- Systematic Study of the Stereoelectronic Properties of Trifluoromethylated Triarylphosphines and the Correlation of their Behaviour as Ligands in the Rh-Catalysed Hydroformylation
-
The stereoelectronic properties of a series of trifluoromethylated aromatic phosphines have been studied using different approaches. The σ-donating capability has been evaluated by nuclear magnetic resonance (NMR) spectroscopy of the selenide derivatives and the protonated form of the different trifluoromethylated phosphines. The coupling constants between phosphorous and selenium (1JSeP) and phosphorous and hydrogen (1JHP) can be predicted by empirical equations and correlate the basicity of the phosphines with the number and relative position of trifluoromethyl groups. In contrast, the π-acceptor character of the ligands has been evaluated by measuring the frequency of the CO vibration in the infrared (IR) spectra of the corresponding Vaska type iridium complexes ([IrCl(CO)(PAr3)2], PAr3=triarylphosphine). Moreover, the correlation between the electronic properties and the performance of these phosphines as ligands in the rhodium-catalysed hydroformylation of 1-octene has been established. Phosphines with the lowest basicity, that are those with the highest number of trifluoromethyl groups, gave rise to more active catalytic systems.
- Herrera, Daniel,Peral, Daniel,Cordón, Mercedes,Bayón, J. Carles
-
supporting information
p. 354 - 363
(2020/12/30)
-
- ENAMINE COMPOUND AND USE THEREOF
-
Provided are a donor-acceptor type compound having a novel structure and its use. An enamine compound represented by general formula (1) (in the formula: R1 represents an electron-withdrawing group;A represents a divalent aromatic hydrocarbon group which may contain a substituent, a divalent aromatic heterocyclic group which may contain a substituent or a divalent unsaturated aliphatic hydrocarbon group which may contain a substituent;R2 represents a hydrogen atom or a hydrocarbon group which may contain a substituent;R3 and R4 are the same or different from each other and represent an aromatic hydrocarbon group which may contain a substituent or an aromatic heterocyclic group which may contain a substituent, or R3 and R4 together form an optionally substituted bicyclic aromatic heterocyclic group containing two or more nitrogen atoms or a nitrogen atom and an oxygen atom or a sulfur atom, or a tricyclic aromatic heterocyclic group which may contain a substituent; andR2 and A, or R2 and R3 may together form a cyclic structure).
- -
-
Paragraph 0111; 0115-0120
(2020/03/28)
-
- Experimental and theoretical mechanistic investigation of the iridium-catalyzed dehydrogenative decarbonylation of primary alcohols
-
The mechanism for the iridium-BINAP catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of molecular hydrogen and carbon monoxide was studied experimentally and computationally. The reaction takes place by tandem catalysis through two catalytic cycles involving dehydrogenation of the alcohol and decarbonylation of the resulting aldehyde. The square planar complex IrCl(CO)(rac-BINAP) was isolated from the reaction between [Ir(cod)Cl]2, rac-BINAP, and benzyl alcohol. The complex was catalytically active and applied in the study of the individual steps in the catalytic cycles. One carbon monoxide ligand was shown to remain coordinated to iridium throughout the reaction, and release of carbon monoxide was suggested to occur from a dicarbonyl complex. IrH2Cl(CO)(rac-BINAP) was also synthesized and detected in the dehydrogenation of benzyl alcohol. In the same experiment, IrHCl2(CO)(rac-BINAP) was detected from the release of HCl in the dehydrogenation and subsequent reaction with IrCl(CO)(rac-BINAP). This indicated a substitution of chloride with the alcohol to form a square planar iridium alkoxo complex that could undergo a β-hydride elimination. A KIE of 1.0 was determined for the decarbonylation and 1.42 for the overall reaction. Electron rich benzyl alcohols were converted faster than electron poor alcohols, but no electronic effect was found when comparing aldehydes of different electronic character. The lack of electronic and kinetic isotope effects implies a rate-determining phosphine dissociation for the decarbonylation of aldehydes.
- Olsen, Esben P. K.,Singh, Thishana,Harris, Pernille,Andersson, Pher G.,Madsen, Robert
-
supporting information
p. 834 - 842
(2015/01/30)
-
- Phosphine, isocyanide, and alkyne reactivity at pentanuclear molybdenum/tungsten-iridium clusters
-
The trigonal bipyramidal clusters M2Ir3(μ-CO)3(CO)6(η5-C5H5)2(η5-C5Me4R) (M = Mo, R = Me 1a, R = H; M = W, R = Me, H) reacted with iso
- Simpson, Peter V.,Randles, Michael D.,Gupta, Vivek,Fu, Junhong,Moxey, Graeme J.,Schwich, Torsten,Morshedi, Mahbod,Cifuentes, Marie P.,Humphrey, Mark G.
-
supporting information
p. 7292 - 7304
(2015/04/27)
-
- Slow exchange of bidentate ligands between rhodium(I) complexes: Evidence of both neutral and anionic ligand exchange
-
The phosphine double exchange process involving [RhCl(COD)(TPP)] and [Rh(acac)(CO)(TMOPP)] (TPP = PPh3, TMOPP = P(C6H4-4-OMe)3) to yield [RhCl(COD)(TMOPP)] and [Rh(acac)(CO)(TPP)] is very rapid but is followed by a much slower process where the bidentate ligands are exchanged to yield [Rh(acac)(COD)] and a mixture of [RhCl(CO)(TPP)2], [RhCl(CO)(TMOPP)2], and [RhCl(CO)(TPP)(TMOPP)]. The exchange involving [RhCl(COD)(L)] and [Rh(acac)(CO)(L)] yields [Rh(acac)(COD)] and [RhCl(CO)(L)2], where the reaction is much faster when L = TPP than when L = TMOPP. The mixed-metal system comprising [IrCl(COD)(TPP)] and [Rh(acac)(CO)(TPP)] yields all four complexes [M(acac)(COD)] and [MCl(CO)(TPP)2], where M = Rh and Ir. This illustrates that both a neutral ligand exchange and an anionic ligand exchange occur. Possible pathways for these processes are discussed.
- Chen, Si,Manoury, Eric,Poli, Rinaldo
-
p. 5820 - 5826
(2015/02/19)
-
- Facile N-N activation in benzotriazole: Capturing the dimroth azo/triazole intermediate by complexation to iridium
-
The in situ observation of benzotriazole ring and ring-opened isomers, which result from the Dimroth equilibrium for 1-[(nonafluorobutane) sulfonyl]benzotriazole, 1, in solution by 19F NMR and UV/Vis spectroscopy is reported. Two benzotriazoles
- Bohle, D. Scott,Chua, Zhijie,Perepichka, Inna
-
p. 1304 - 1310
(2013/11/06)
-
- Comparative reactivity of triorganosilanes, HSi(OEt)3 and HSiEt3, with IrCl(CO)(PPh3)2. Formation of IrCl(H)2(CO)(PPh3)2 or Ir(H)2(SiEt3)(CO)(PPh3
-
Reaction of HSi(OEt)3 with IrCl(CO)(PPh3)2 (5:1 molar ratio) at room temperature for 1 h gives IrCl(H){Si(OEt)3}(CO)(PPh3)2 (1), which is observed by the 1H and 31P{s
- Nishihara, Yasushi,Takemura, Miwa,Osakada, Kohtaro
-
p. 2951 - 2956
(2009/10/01)
-
- Unexpected formation of a weak metal-metal bond: Synthesis, electronic properties, and second-order NLO responses of push-pull late-early heteronuclear bimetallic complexes with W(CO)3(1,10-phenanthroline) acting as a donor ligand
-
In attempts to bridge the complex [W(CO)3(phen)(pyz)] (phen = 1,10-phenanthroline; pyz = pyrazine) to acceptor centers, either soft centers such as cis-M(CO)2CL (M = Rh(I), Ir(I)) and fac-M(CO)3Cl2 (M = Ru(II), Os(II)) or hard centers such as BF3, the pyrazine ligand is lost, while the fragment W(CO)3(phen) behaves as a σ-donor base with the unexpected formation of heteronuclear early-late bimetallic compounds with a weak metal-metal bond, as confirmed by the easy substitution of W(CO)3(phen) by soft ligands (PPh3, CO, pyridine). The X-ray structures of [(CO)3(phen)W-cis-Ir(CO)2Cl] and [(CO)3(phen)W-fac-Os(CO)3Cl2] confirm a single metal-metal bond with an halogen bridging asymmetrically the two metallic moieties and with the tungsten atom achieving a distorted (6 + 1) octahedral coordination. All the heteronuclear bimetallic complexes investigated show in their electronic spectra a new solvatochromic absorption band at around 385-450 nm in addition to the MLCT (W→π*phen) absorption band typical of [W(CO)3(phen)L] complexes (L = CO, pyz, CH3CN) and an increased, in comparison to [W(CO)4(phen)], negative nonlinear (NLO) second-order emission working with the EFISH technique with an incident wavelength of 1.907 μm. The increase is due to an additional negative contribution of the new absorption band at around 385-450 nm, as shown by a solvatochromic investigation.
- Pizzotti, Maddalena,Ugo, Renato,Dragonetti, Claudia,Annoni, Elisabetta,Demartin,Mussini
-
p. 4001 - 4011
(2008/10/08)
-
- Synthesis of cross-conjugated olefins from alkynes: Regioselective C-C bond formation between alkynes
-
Reactions of cis-dihydrido complex [Ir(H)2(NCCH3)2(PPh3)2] + (1) with HC≡CH and RC≡CH (R = C6H5, p-C6H4CH3, cyclohex-1-enyl, C(CH3)=CH2, C(CH3)3) produce cross-conjugated hexatrienes (RCH=C(CH=CH2)2, R-HEX) and octatetraenes (H2C=CH-CR=CH-C(-CH= CH2)=CHR, R2-OCT). Two molecules of HC≡CH are inserted into Ir-H bonds of 1 to give cis-bis(ethenyl) complex [Ir(CH==CH2)2(NCCH3)2(PPh3 )2]+ (2), which reacts with RC≡CD to produce both R-HEX-d1 (RCD=C(CH=CH2)2) and R2-OCT-d2 (H2C=CH-CR=CD-C(-CH= CH2)=CDR). R-HEX are exclusively obtained from the reactions of RC≡CH with [Ir(CH= CH2)2(CO)2(PPh3)2]+ (3). Alkynyl cis-bis(ethenyl) complexes Ir(CH=CH2)2(C≡CR)(CO)(PPh3)2 (4, R = C6H5 (a), p-C6H4CH3 (b), cyclohex-1-enyl (c)) react with D+ to give η4-R-HEX-d1 complexes [Ir(η4-RCD=C(CH=CH2)2)(CO)(PPh3) 2]+ (5-d1) from which R-HEX-d1 are obtained in the presence of a base. Di- and trinuclear alkynyl-bis(alkenyl) complexes [L5Ir-C≡Cp-C6H4-C≡C-IrL5 ] (7, L5 = (-CH=CH2)2(CO)(PPh3)2) and [L5Ir-C≡C-m,m-C6H3-(C≡C-IrL5 )2] (8, L5 = (-CH=CH2)2(CO)(PPh3)2) react with H+ to produce extended cross-conjugated olefins, p-C6H4-(HEX)2 and m,m-C6H3-(HEX)3, respectively, in high yields. Plausible reaction pathways involve alkenyl-vinylidene complexes that undergo the C-C bond formation reaction between the two hydrocarbyl ligands to produce the cross-conjugated olefins.
- Chin, Chong Shik,Lee, Hyungeui,Park, Hyeyun,Kim, Mieock
-
p. 3889 - 3896
(2008/10/08)
-
- A facile route to carbonylhalogenometal complexes (M = Rh, Ir, Ru, Pt) by dimethylformamide decarbonylation
-
Dimethyl formamide (DMF) can be a convenient source of the carbonyl ligand in the coordination chemistry of rhodium, ruthenium, iridium, and platinum. We have undertaken a thorough study concerning the course of this reaction. In a first step, DMF-containing complexes are produced, which is usually accompanied by chloride redistribution. Then, upon refluxing, carbonyl species in the same oxidation state are obtained, presumably as a result of HCl-mediated DMF decomposition. Provided that water levels are kept low, reduction can occur to provide the complexes [NH2(CH3)2][RhCl2(CO) 2], [NH2(CH3)2][RuCl3(CO) 2(DMF)], [RuCl2(CO)2(DMF)2], and [NH2(CH3)2][IrCl2(CO) 2]. In the case of platinum, reduction is not effective and [NH2(CH3)2][PtCl3(CO)] is obtained. No carbonylpalladium species can be synthesized in this way, the reaction producing copious amounts of colloidal metal. Adding phosphanes to these chlorocarbonyl-containing solutions allows easy, one-step syntheses of a variety of complexes.
- Serp, Philippe,Hernandez, Marc,Richard, Brigitte,Kalck, Philippe
-
p. 2327 - 2336
(2007/10/03)
-
- Oxidative addition and reductive elimination reactions of trans-[Ir(PPh3)2(CO)(NC4H4)] and trans,cis-[Ir(PPh3)2(H)2(CO)(NC 4H4)], including N-H bond-forming reductive elimination of pyrrole
-
The complex trans-(PPh3)2(CO)Ir(NC4H4) (1) has been synthesized and is an analogue of metal-aryl complexes, but with a nitrogen of the heteroaromatic group covalently bonded to the transition metal. Compound 1 readily undergoes initial reaction with a variety of substrates at the metal center rather than at the pyrrolyl nitrogen, allowing for the study of reactions between the pyrrolyl group and accompanying covalent ligands. These reactions ultimately produce N-substituted pyrroles, X-NC4H4 (X = C(O)CH3, C(O)C6H4CH3, H, SnMe3, SiMe3, SiEt3, Bcat). Compound 1 undergoes oxidative addition of H2 to form the stable Ir-(III) product (PPh3)2(CO)Ir(H)2(NC4H4) (2). When pure 2 is heated, it undergoes simple elimination of H2 to regenerate 1; however, if 2 is heated for longer times under H2 in the presence of PPh3, it undergoes reductive elimination of pyrrole and forms (PPh3)3(CO)Ir(H). Qualitative analysis of the mechanism of this reaction suggests that it occurs by either direct reductive elimination from the octahedral complex or rate-determining ligand dissociation, followed by rapid reductive elimination of pyrrole. Reductive elimination of pyrrole from 2 was also observed to occur photochemically by initial irreversible dissociation of a dative ligand.
- Driver, Michael S.,Hartwig, John F.
-
p. 1134 - 1143
(2008/10/08)
-
- Synthesis and Complexation Behavior of the Functionalized Tripodal Phosphane cis,cis-1,3,5-Tris(cyano)-1,3,5-tris(diphenylphosphanyl)cyclohexane (tdppcycn)
-
The synthesis of the novel potentially bistripodal ligand cis,cis-1,3,5-tris(cyano)-1,3,5-tris(diphenylphosphanyl)cyclohexane (tdppcycn) (6) is described.Starting from the tricarboxylic acid cis,cis-1,3,5-C6H9(COOH)3 (1), which is converted stepwise into triacid chloride cis,cis-1,3,5-C6H9(COCl)3 (2), the triphenyl ester cis,cis-1,3,5-C6H9(COOPh)3 (3), the tricarboxamide cis,cis-1,3,5-C6H9(CONH2)3 (4), and the tricarbonitrile cis,cis-1,3,5-C6H9(CN)3 (5), we obtained tdppcycn (6) by α-deprotonation of 5 followed by treatment with ClPPh2 in good yield.Treatment of 6 with Mo(CO)3(η6-C7H8) and Ir(PPh3)2(CO)Cl gave octahedral Mo(tdppcycn)(CO)3 (7) and pentacoordinate Ir(tdppcycn)(CO)Cl (8), respectively, with a facially P-coordinated tdppcycn ligand.The stereochemistry of compounds 2-8 was established by 1H-, 13C-, 31P-NMR, and IR spectroscopy.An X-ray crystal structure analysis of complex 8 confirms the trigonal-bipyramidal ground-state structure in the solid state. - Keywords: Phosphane ligands, tripodal; Molybdenum complexes; Iridium complexes
- Mayer, Hermann A.,Stoessel, Philipp,Fawzi, Riad,Steimann, Manfred
-
p. 719 - 724
(2007/10/03)
-
- The synthesis of ionic iridium(III) carbene complexes of the type Cl(OSO2CF3)(CO)(PPh3)2>+-
-
The title compounds in which R = C6H5, 4-MeC6H4, 4-EtC6H4 and CH3 have been prepared in moderate to good yield by the reaction between and the corresponding N-methylnitrilium triflate salts NMe>+-/s
- Booth, B.L.,Wickens, A.C.
-
p. 283 - 286
(2007/10/02)
-
- Ligand redistribution reactions of some organometallic rhodium and iridium complexes
-
Ligand redistribution reactions of some organometallic rhodium and iridium complexes have been investigated and their possible reaction pathways have been discussed.
- Stang, Peter J.,Huang, Yo-Hsin
-
p. 185 - 192
(2007/10/02)
-
- Synthesis, characterization, and reaction chemistry of the novel heterobimetallic iridium-platinum complexes [(PR3)2(CO)Ir(μ-H)(μ-η2:η 1-CH=CH2)Pt(PR′3)2] +[OTf]-
-
Reactions of Ir(I)-triflate complexes trans-Ir(OTf) (CO) (PR3)2 (PR3 = PPh3, 1; PR3 = PMePh2, 2) with Pt0-π-ethylene complexes Pt(H2C=CH2)(PR′3)2 (PR′3 = PPh3, 3; (PR′3)2 = Ph2P(CH2)3PPh2, 4) in CH3NO2 result in C-H bond activation and the ready formation of the novel heterobimetallic Ir-Pt complexes [(PR3)2(CO)Ir(μ-H)(μ-η2:η 1-CH=CH2)Pt(PR′3)2] +[OTf]- (PR3 = PR′3 = PPh3, 5; PR3 = PMePh2, PR′3 = PPh3, 6; PR3 = PPh3, (PR′3)2 = Ph2P(CH2)3PPh2, 7; PR3 = PMePh2, (PR′3)2 = Ph2P(CH2)3PPh2, 8). A definitive structural determination for these heterobimetallic Ir-Pt complexes has been established by an X-ray diffraction study on complex 5 (triclinic, P1 (No. 2), a = 13.321 (1) A?, b = 15.461 (2) A′, c = 17.753 (2) A?, α= 90.37 (1)°, β = 95.47 (1)°, γ = 100.92 (1)°, Z = 2). Reactivity tests with one of the heterobimetallic complexes 7, using Ph2P(CH2)3PPh2 and acids, have also been conducted.
- Stang, Peter J.,Huang, Yo-Hsin,Arif, Atta M.
-
p. 845 - 852
(2008/10/08)
-
- Vinylidene Transition Metal Complexes, XVII. - Synthesis of trans- CPh)(PMe2tBu)3>, and of some Dihydridoiridium(III) Complexes
-
2 (1) reacts with PMetBu2 in the presence of H2 to give (2).Treatment of 2 with acetylene yields the vinylidene complex trans- (3).The reaction of 1 with PMePh2 or PMe2tBu in the presence of H2 leads to the formation of fac- (4a, 5a), which on warming to 60 deg C rearrange to give the more stable mer isomers 4b, 5b.Treatment of 1 with PMePh2 or PMe2tBu and phenylacetylene affords the hydrido(phenylethynyl)iridium(III) compounds mer-CPh)(PR3)3> (8, 9), which could not be converted by phosphine elimination to the corresponding (phenylvinylidene)iridium complexes.The synthesis of trans- (11) has been achieved by CO abstraction from CH)(CO)(PPh3)2> (13) by using trimethylamine oxide. Key words: (Vinylidene)iridium(I) complexes; iridium(III), dihydrido complexes; isomerization, fac-mer; iridium(III), (phenylethynyl) complexes, CO abstraction.
- Werner, Helmut,Dirnberger, Thomas,Hoehn, Arthur
-
p. 1957 - 1962
(2007/10/02)
-
- Coordinatively unsaturated ?-aryl iridium(III) complexes containing iridium-mercury bonds
-
Reaction between the iridium(III) complex IrHCl2(PPh3)3 and Hg(o-tolyl)2 yields the red, coordinatively unsaturated, mercury-containing, iridium(III) complex Ir(o-tolyl)Cl(PPh3)2 (1). 31P-199Hg coupling in the 31P NMR spectrum of 1 confirms t
- Roper, Warren R.,Saunders, Graham C.
-
p. C19 - C22
(2007/10/02)
-
- The coordination chemistry of iminooxosulphuranes. The osmium and iridium series (ML = OsNO,IrCO;A = O, CH2, S, NR; R = o-tolyl, p-tolyl and p-tosyl)
-
The preparation and characterisation of the two analogous series of compounds (A = O, CH2, S, NR; R = C6H4Me-4, C6H4Me-2, SO2C6H4Me-4) and (A = O, S, NSO2C6H4Me-4) are described.A comparison of spectroscopic data for the complex supports the isolobal relationship between the molecules OSA.
- Herberhold, Max,Hill, Anthony F.
-
p. 323 - 336
(2007/10/02)
-
- Reactions of iridium(I) alkoxide complexes with acyl and alkyl sources: Carbon-oxygen bond-forming reactions
-
The reactions of alkoxyiridium complexes trans-ROIr(CO)(PPh3)2 (R = Me, Ph, t-Bu, i-Pr) with organic substrates R′X (R′ = Me, CH3C(O), C6H5C(O), C6H5CH2C(O), HC(O); X = Cl, I, H)
- Bernard, Karen A.,Atwood, Jim D.
-
p. 795 - 800
(2008/10/08)
-
- Novel Halogen Exchange Reactions between Halosilanes and Rh(I) or Ir(I) Complexes
-
Vaska-type complexes such as MCl(CO)L2 (M=Rh or Ir, L= tertiary phosphine) or the Wilkinson complex RhCl(PPh3)3 underwent halogen exchange reactions with halosilanes Me3SiX (X=Br, I) to give MX(CO)L2 or RhX(PPh3)3 respectively with the formation of Me3SiC
- Yamashita, Hiroshi,Kobayashi, Toshi-aki,Hayashi, Teruyuki,Tanaka, Masato
-
p. 471 - 474
(2007/10/02)
-
- Novel Synthetic Routes to Disulphur and Disulphur Monoxide Ligands: Nucleophilic Attack at Co-ordinated Imino-oxo-λ4-sulphanes
-
The reactions of and with oxo-4-tosylimino-λ4-sulphane (4-MeC6H4SO2NSO) lead quantitatively to the adducts Cl(PPh3)2(4-MeC6H4SO2NSO)> = Os(NO) or Ir(CO)> which in turn are hydrolysed to the corresponding sulphur dioxide complexes Cl(PPh3)2(SO2)>.The iridium compound reacts cleanly with hydrogen sulphide to provide the disulphur monoxide complex whilst with hydrosulphide leads to the disulphur complex which may be oxidised to the corresponding S2O complex with 3-chloroperbenzoic acid.Alternatively, is accessible via the reaction of with cyclo-octasulphur.
- Herberhold, Max,Hill, Anthony F.
-
p. 2027 - 2032
(2007/10/02)
-
- Thermal and photolytic reactions of nitrosyl-carbonyl complexes of rhodium and iridium with triphenylphosphine
-
The photolysis of [Rh(NO)(CO)(PPh3)2] in the presence of PPh3 in dichloromethane results in the expulsion of NO rather than CO and the formation of trans-[Rh(CO)Cl(PPh3)2]. The thermal reaction and photoreaction of [Ir(NO)(CO)Cl(PPh3)2]BF4 (1) with PPh3 lead to dissociation of NO and the formation of the Ir(II) radical [Ir(CO)Cl(PPh3)3]BF4 (2). The demonstration of the homolytic cleavage of the Ir-NO bond of 1 provides support for the proposal that the photodissociation of NO instead of CO in the compounds [M(NO)(CO)(PPh3)2] (where M is Rh or Ir) proceeds from a charge-transfer state that has a bent M-N-O bond.
- Kubota, Mitsuru,Chan, Michael K.,Boyd, David C.,Mann, Kent R.
-
p. 3261 - 3264
(2008/10/08)
-
- Selectivity in C-O bond formation: Reaction of acid chlorides and methyl iodide with trans-MeOIr(CO)(PPh3)2
-
Reactions of RX (RX = MeI, CH3C(O)Cl, C6H5C(O)Cl, and C6H5CH2C(O)Cl) with trans-MeOIr(CO)(PPh3)2 have been examined. In each case, an adduct is formed, RIr(OMe)(CO)(PPh3)2X, which is stable for R = Me. For the acid chlorides, this adduct eliminates ester, forming Ir(CO)(PPh3)2Cl. Thus the carbon-oxygen bond leading to ester products is formed more readily than the carbon-oxygen bond leading to dimethyl ether.
- Bernard, Karen A.,Atwood, Jim D.
-
p. 1133 - 1134
(2008/10/08)
-
- Diazoalkane activation by iridium phosphine compounds. 1. Complexes containing the intact dibenzoyldiazomethane ligand and interconversion between the η1-N-bound and a chelated N,O-bound form of the ligand accompanied by hydride migration
-
The reaction of dibenzoyldiazomethane (N2C(C(O)Ph)2) with trans-[IrCl(N2)(PPh3)2] yields the four-coordinate species [IrCl(N2C(C(O)Ph)2)(PPh3)2] (1) in which the intact diazoalkane molecule is coordinated in a η1, singly bent geometry. Compound 1 reacts with donor ligands, L, to give five-coordinate adducts of formulation [IrCl(N2C(C(O)Ph)2)(L)(PPh3)2] (L = PMe2Ph, t-BuNC, and NO+). The reaction of 1 with 1 equiv of HCl yields an equilibrium mixture of [IrHCl2(N2C(C(O)Ph)2)(PPh3) 2] and [IrCl2(HN2C(C-(O)Ph)2)(PPh3) 2] in which hydride migration from Ir to the coordinated nitrogen atom occurs; the latter species is present in an approximate 15:1 excess. An X-ray structure determination of the second (more abundant) species was undertaken. It crystallizes in the space group P21/c with a = 10.165 (2) A?, b = 17.422 (2) A?, c = 25.653 (5) A?, β = 93.66 (2)°, V = 4533.7 A?3, and Z = 4. The structure has refined to R = 0.044 and Rw = 0.050 based on 190 variables and 1869 unique observations. The compound is a six-coordinate Ir(III) species in which the reduced diazoalkane ligand is coordinated to Ir through the terminal nitrogen atom, which also is bound to the H atom, and a benzoyl oxygen atom.
- Cowie, Martin,Loeb, Stephen J.,McKeer, Ian R.
-
p. 854 - 860
(2008/10/08)
-
- A convenient general synthesis of trans-[IrCl(CO)(PR3)2]
-
[IrCl(cod)]2 is treated at room temperature with 4 mol equiv of PR3 (R = Ph, C6H11, o-MeC6H4) and then CO to give the title complexes. In the case of PMe3, [IrCl(cod)]2 was converted to the new complex [IrCl(cod)(PMe3)2], which on treatment with CO gave [IrCl(CO)2(PMe3)2]. This readily loses CO in vacuo at 25°C and in the solid state to give the title complex, which is a reversible CO carrier.
- Burk, Mark J.,Crabtree, Robert H.
-
p. 931 - 932
(2008/10/08)
-
- Carborane reductive-elimination reaction from a six-coordinate hydridocarboranyliridium(III) complex: Kinetic and mechanistic study
-
A kinetic and mechanistic study of the reductive-elimination reaction of the carborane 1-H-T-C6H5-1,7-C2B10H10 (H-carb) from the six-coordinate iridium(III) complex Ir(H)(Cl)(σ-carb)(CO)(PPh3)2 has been carried out in 1,2-dichloroethane by IR spectroscopy between 20 and 50°C. The mechanism of the carborane-elimination reaction implies a preliminary PPh3 dissociation to give the five-coordinate Ir(H)(Cl)(σ-carb)(CO)(PPh3) complex. This intermediate then undergoes a reductive elimination of the carborane molecule through two pathways: (i) direct elimination to give the three-coordinate iridium(I) complex, IrCl(CO)(PPh3); (ii) a phosphine-induced elimination via trans → cis isomerization of the H and carb ligands. The kinetic and thermodynamic parameters are also reported and discussed.
- Basato,Morandini,Longato,Bresadola
-
p. 649 - 653
(2008/10/08)
-
- Heterobimetallic phosphido-bridged complexes containing coordinatively unsaturated rhodium(I) and iridium(I) centers. Structural characterization of FeIr(μ-PPh2)(CO)5(PPh3)2
-
The series of new phosphido-bridged heterometallic binuclear complexes FeM(μ-PPh2)(CO)x(L)2 (M = Rh, L = PEt3, x = 4, 5; M = Ir, L = PPh3, x = 4-6) have been synthesized by the reaction of Li[Fe-(CO)4(PPh2)] with the appropriate irans-MCl(CO)L2 complex. The new complexes have been characterized spectroscopically, and FeIr(μ-PPh2)(CO)5(PPh3)2 has been characterized by a complete single-crystal X-ray diffraction study. It crystallizes in the space group P1 with a = 11.681 (3) A?, b = 20.869 (4) A?, c = 10.649 (9) A?, α = 96.74 (3)°, β = 108.86 (3)°, γ = 76.51 (2)°, V = 2386 (3) A?3, and Z = 2. Diffraction data (0° ≤ 2θ ≤ 50°) were collected with an Enraf-Nonius CAD4 automated diffractometer, using graphite-monochromatized Mo Kα radiation, and the structure was refined to R = 0.053 and Rw = 0.077 for 6257 independent reflections with I ≥ 3.0σ(I). The μ-PPh2 ligand bridges the Fe and Ir atoms, and each metal is ligated by a PPh3 ligand. The Fe is further ligated by three CO's and the Ir by two. The relatively long Fe-Ir bond length of 2.960 (1) A? suggests a weak donor-acceptor type interaction between the two metal centers. Each of the new compounds undergoes a series of reversible addition/elimination reactions with CO, and the Fe-Ir compounds react with H2 to give new H2 adducts.
- Roberts, David A.,Steinmetz, Guy R.,Breen, Michael J.,Shulman, Peter M.,Morrison, Eric D.,Duttera, Michael R.,DeBrosse,Whittle, Robert R.,Geoffroy, Gregory L.
-
p. 846 - 855
(2008/10/08)
-
- Chelate-assistftd oxidative addition of functlonallzed phosphlnes to irldlum(I)
-
This paper is concerned with an evaluation of the factors which influence the facility of the oxidative addition of chelating substrates. Spectrophotometrically we determined the for the chelating substrates ere than those for the nonchelating substrates.
- Landvatter, Edith F.,Raoctifuss, Thomas B.
-
p. 506 - 513
(2008/10/08)
-
- REACTIONS OF SOME OXIRANES WITH RHODIUM(I) AND IRIDIUM(I) SPECIES
-
Tetracyanooxirane oxidatively adds to rhodium(I) and iridium(I) species to afford metal(III) compounds.With trans-RhCl(CO)(PPh3)2 a reaction in boiling C6H6 produces RhCl(CN)(OC2(CN)3)(CO)(PPh3)2, a rhodium(III)(cyano)(tricyanoenolato) compound.Characteri
- Osborne, Robert B.,Ibers, James A.
-
p. 273 - 278
(2007/10/02)
-
- Rections involving Metals. Part 14. The Preparation of Novel Alkyl peroxy(carboxylato)iridium(III) Complexes
-
Treatment of the di(alkyl peroxy)iridium(III) complexes 1)2(CO)(PPh3)2> (X = Cl or Br) with organic acids, R2CO2H, having a pKa >ca. 4.0 results in the substitution of only one of the alkyl peroxy-ligands with formation of 1)(OCOR2)(CO)(PPh3)2> (R1 = But, R2 = CF3, CCl2, CHCl2, CO2H, cis-CH=CHCO2H, C6F5, or H; R1 = CMe2Ph, R2 = CF3), and t)(OCOR2)(CO)(PPh3)2> (R2 = CF3 or H).The related compounds t)(CO)(PPh3)2> (X= Y = Cl or Br; X = Cl, Y = Br or NO3) have also been obtained by reaction of t)2(CO)(PPh3)2> (X = Br or Cl) with HCl, HBr, or HNO3 at 0 deg C.At higher temperatures t)(CO)(PPh3)2 and t)(OCOCCl3)(CO)(PPh3)2> react with HCl to give .
- Booth, Brian L.,Haszeldine, Robert N.,Neuss, Geoffrey R.H.
-
p. 511 - 516
(2007/10/02)
-
- REACTIONS INVOLVING TRANSITION METALS. XX. A COMPARISON OF THE REACTIONS OF 1,2,3,4,7,7-HEXAFLUOROBICYCLOHEPTADIENE, AND 2,3-BIS(TRIMETHYLTIN)- AND 2,3-DICHLORO-1,4,5,6,7,7-HEXAFLUOROBICYCLOHEPTA-2,5-DIENES WITH LOW VALENT TRANSITION METAL COMPLEXES
-
1,2,3,4,7,7-hexafluorobicycloheptadiene (1) and 2,3-bis(trimethyltin)-1,4,5,6,7,7-hexafluorobicyclohepta-2,5-diene (2) react with (M = Pt, Pd) to afford air-stable adducts. 2,3-Dichloro-1,4,5,6,7,7-hexafluorobicyclohepta-2,5-diene (3) gives only with , but a low yield of an adduct was obtained with .The diene 1 also reacts with Fe(CO)5 to form the complex , and with to give in which the diene acts as a bidentate ligand.Similar products could not be isolated from the reactions of 2 and 3.A stable adduct, believed to be Rh(CO)2(μ-Cl)2Rh(CO)2> has been isolated from the reaction between 2 and 2.This adduct reacts with PPh3 to give the bridge-cleavage product RhCl(CO)(PPh3)2>.Reaction of 1 with 2 gives an unstable adduct which could not be isolated, and 2 does not react at room temperature.The chloro derivative 3 reacts with to give the adduct , but 1 and 2 do not react under similar conditions.Stable substitution products (R = H, M = Fe(CO)2(η-C5H5); R = SnMe3, M = Fe(CO)2(η-C5H5), Mn(CO)5, Ir(CO)2(PPh3)2, Rh(CO)2(PPh3)2; R = Cl, M = Ir(CO)2(PPh3)2, Rh(CO)2(PPh3)2) have been isolated from the reactions of the dienes with carbonylmetal anions.Insertion of the CH=CH bond occurs when 1 is heated with to give and this, on reaction with either PPh3 or , gives .
- Booth, Brian L.,Casey, Sylvia,Critchley, Robert P.,Haszeldine, Robert N.
-
p. 301 - 312
(2007/10/02)
-
- REACTIONS INVOLVING TRANSITION METALS. XIX. SOME REACTIONS OF PERFLUORONORBORNADIENE WITH LOW VALENT TRANSITION METAL COMPLEXES
-
Perfluoronorbornadiene reacts with the compounds to give the adducts and in which one of the double bonds is coordinated to the metal atom.The platinum complex reacts further with to give 2> having both double bonds coordinated to a Pt atom.The carbonylmetal anions -> react to form the mono-substitution products (M = Mn(CO)5, Re(CO)5, Ir(CO)2(PPh3)2, Rh(CO)2(PPh3)2, but the use of an excess of - leads to substitution of one fluorine atom on each of the double bonds.The complex having M = Mn(CO)5 reacts with to afford the derivative >, and the compound where M = Ir(CO)2(PPh3)2 undergoes an oxidative addition reaction with acetyl chloride.Oxidative coupling products have been isolated on UV irradiation of a mixture of perfluoronorbornadiene and 4-CH2=CRCH=CH2)(CO)3> (R = H, Me), and under similar conditions the reaction with Fe(CO)5 affords in very low yield.
- Booth, Brian L.,Casey, Sylvia,Haszeldine, Robert N.
-
p. 289 - 300
(2007/10/02)
-
- Preparation and interconversion of two isomeric iridium trihydrides
-
The preparation, separation, and structural characterization of a,b,c-trihydrido-f-carbonylbis(triphenylphosphine)iridium(III) and a,b,f,-trihydrido-d-carbonylbis(triphenylphosphine)iridium(III) are described. The kinetics of interconversion of the two isomers and of the displacement of H2 from both isomers by triphenylphosphine have been measured and indicate that interconversion occurs via reversible reductive elimination/oxidation sequence. Both the isomerization and substitution reactions are postulated to involve the intermediate IrH(CO)P2. The relationship of the present results to other studies of the stereochemistry of oxidative additions to square-planar iridium(I) complexes is discussed.
- Harrod,Yorke
-
p. 1156 - 1159
(2008/10/08)
-