Synthesis, Molecular Structure, and Reactivity of Iridium(I) and Iridium(III) Complexes Formed by Coordination and C−H Activation of the Substituted Arenes C6H5CH2CH2PiPr2and C6H5OCH2CH2PtBu2

Canepa, Giuseppe; Sola, Eduardo; Martı́n, Marta; Lahoz, Fernando J.; Oro, Luis A.; Werner, Helmut

doi:10.1021/om0210457

Cited by 20 publications

(34 citation statements)

References 12 publications

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“…Solvents were dried by known procedures and distilled before used. The starting materials 2, [28] 7, [29] 26, [7] 29, [7] 33, [7] 36, [30] the phosphanes L 1 and L 2 , [7] and the phosphonium salts L 1 ¥ HBF 4 and 38 [26] were prepared as described in the literature. NMR spectra were recorded (at room temperature or at the temperature mentioned in the appropriate procedure) on Bruker AC 200 and AMX 400 instruments (abbreviations used: s, singlet; d, doublet; t, triplet; q, quartet; sept, septet; m, multiplet; br, broadened signal; virt., virtual coupled), IR spectra on a Bruker IFS 25 FT-IR spectrometer, and mass spectra on a Finnigan MAT 90 instrument.…”

Section: Methodsmentioning

confidence: 99%

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Rhodium(I) and Rhodium(III) Complexes Formed by Coordination and CH Activation of Bulky Functionalized Phosphanes

Canepa

Brandt

Ilg

et al. 2003

Chemistry A European J

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The reaction of [[RhCl(C(8)H(14))(2)](2)] (2) with iPr(2)PCH(2)CH(2)C(6)H(5) (L(1)) led, via the isolated dimer [[RhCl(C(8)H(14))(L(1))](2)] (3), to a mixture of three products 4 a-c, of which the dinuclear complex [[RhCl(L(1))(2)](2)] (4 a) was characterized by Xray crystallography. The mixture of 4a-c reacts with CO, ethene, and phenylacetylene to give the square-planar compounds trans-[RhCl(L)(L(1))(2)] (L=CO (5), C(2)H(4) (6), C=CHPh (9)). The corresponding allenylidene(chloro) complex trans-[RhCl(=C=C=CPh(2))(L(1))(2)] (11), obtained from 4 a-c and HC triple bond CC(OH)Ph(2) via trans-[RhCl[=C=CHC(OH)Ph(2)](L(1))(2)] (10), could be converted stepwise to the related hydroxo, cationic aqua, and cationic acetone derivatives 12-14, respectively. Treatment of 2 and [[RhCl(C(2)H(4))(2)](2)] (7) with two equivalents of tBu(2)PCH(2)CH(2)C(6)H(5) (L(2)) gave the dimers [[RhCl(C(8)H(14))(L(2))](2)] (15) and [[RhCl(C(2)H(4))(L(2))](2)] (16), which both react with L(2) in the molar ratio of 1:2 to afford the five-coordinate aryl(hydrido)rhodium(III) complex [RhHCl(C(6)H(4)CH(2)CH(2)PtBu(2)-kappa(2)C,P)(L(2))] (17) by C-H activation. The course of the reactions of 17 with CO, H(2), PhC triple bond CH, HCl, and AgPF(6), leading to the compounds 19-21, 24, and 25 a, respectively, indicate that the coordinatively unsaturated isomer of 17 with the supposed composition [RhCl(L(2))(2)] is the reactive species. Labeling experiments using D(2), DCl, and PhC triple bond CD support this proposal. With either [Rh(C(8)H(14))(eta(6)-L(2)-kappaP]PF(6) or [Rh(C(2)H(4))(eta(6)-L(n)-kappaP]PF(6) (n=1 and 2) as the starting materials, the corresponding halfsandwich-type complexes 27, 28, and 32 were obtained. The nonchelating counterpart of the dihydrido compound 32 with the composition [RhH(2)(PiPr(3))(eta(6)-C(6)H(6))]PF(6) (35) was prepared stepwise from [Rh(C(2)H(4))(PiPr(3))(eta(6)-C(6)H(6))]PF(6) and H(2) in acetone via the tris(solvato) species [RhH(2)(PiPr(3))(acetone)(3)]PF(6) (34) as intermediate. The synthesis of the bis(chelate) complex [Rh(eta(4)-C(8)H(12))(C(6)H(5)OCH(2)CH(2)PtBu(2)-kappa(2)O,P)]BF(4) (39) is also described. Besides 4 a, the compounds 17, 25 a, and 39 have been characterized by Xray crystal structure analysis.

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Section: Methodsmentioning

confidence: 99%

“…The IR spectrum of 37 displays a n(C O) stretching mode at 1652 cm À1 and thus at about the same position as for the iridium(i) counterpart. [26] In the 1 H NMR spectrum of 37 the signal for the protons of the coordinated acetone could not be observed which is probably due to a rapid ligand exchange between (CH 3 ) 2 CO and (CD 3 ) 2 CO used as the solvent.…”

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confidence: 96%

Rhodium(I) and Rhodium(III) Complexes Formed by Coordination and CH Activation of Bulky Functionalized Phosphanes

Canepa

Brandt

Ilg

et al. 2003

Chemistry A European J

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“…[16] Loss of CH 3 CN to form 16 e À intermediate complex [13] and subsequentC (sp 3 )ÀHb ond activation of the neighboring ortho-methyl group,w ould lead to Ir V intermediate [14], [17] which,b yr eductivec oupling, should form the final iridapolycycles (15). The process should begin with the regioselectivem igratory insertion of the alkyne CCb ond into the starting metallacycle.…”

Section: Resultsmentioning

confidence: 99%

“…The process should begin with the regioselectivem igratory insertion of the alkyne CCb ond into the starting metallacycle. [16] Loss of CH 3 CN to form 16 e À intermediate complex [13] and subsequentC (sp 3 )ÀHb ond activation of the neighboring ortho-methyl group,w ould lead to Ir V intermediate [14], [17] which,b yr eductivec oupling, should form the final iridapolycycles (15). The E-stereochemistry of the newly created C=Cb ond is defined during the reductivec oupling step.…”

Section: Resultsmentioning

confidence: 99%

Sequential Reactions of Alkynes on an Iridium(III) Single Site

Giner

Gallego

Merinero

et al. 2017

Chemistry A European J

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Sequential insertion of terminal alkynes on Ir cyclometalated complexes allow the formation of novel metallapolycycles in a controlled and efficient manner. ortho-Methylarylethynyl derivatives led to an unprecedented cascade combination of three fundamental processes (C-C bond formation, C(sp )-H activation, and reductive coupling) on a single Ir center, in a process compatible with functionalized biomolecules and photoactive substrates. The reaction with tert-butylacetylene led to a [6,5,4]-polycycle that incorporates an iridacyclobutenylidene in its structure. The sequence is a multicomponent reaction in which the metal not only promotes the different steps but also determines their stereoselectivity. This is an elegant example of the synergy between a metal-promoting reaction and a symmetry-defined stereochemistry.

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“…A related dihydrido iridium complex of formula [( η 6 -C 6 H 5 CH 2 CH 2 P i Pr 2 -κ -P )IrH 2 ]BF 4 [24] can be prepared by treatment of the dimer [Ir( µ -OMe)(COD)] 2 [15] with the phosphonium salt, [HP i Pr 2 CH 2 CH 2 C 6 H 5 ]BF 4 , in acetone followed by the reaction of hydrogen (Scheme 2.26 ).…”

Section: Dihydrido Arene Iridium Triisopropylphosphine Complexes 31mentioning

confidence: 99%

Dihydrido Iridium Triisopropylphosphine Complexes: From Organometallic Chemistry to Catalysis

Oro

2008

Iridium Complexes in Organic Synthesis

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2.1 IntroductionThe impressive developments of organometallic chemistry have allowed the preparation of a wide variety of soluble metal complexes useful for organic transformations under mild conditions. There is no question that much of the general knowledge on homogeneous catalysis has stemmed from studies of organometallic chemistry and homogeneous hydrogenation. Following the discovery of Wilkinson ' s hydrogenation catalyst, RhCl(PPh 3 ) 3 , in 1964 [1] -which is by far the most -studied homogeneous catalyst -Schrock and Osborn reported the catalytic potential of [Rh(diene)L 2 ] + complexes as hydrogenation catalysts. Under hydrogen, the diene is hydrogenated to generate the reactive [RhH 2 S 2 (PR 3 ) 2 ] + species which, in some cases, can be isolated relatively easily from coordinating solvents (S) such as acetone or ethanol [2] . In contrast to Wilkinson ' s catalyst, a large number of donor ligands can be used, while the use of a PR 3 : Rh ratio of 2 : 1 avoids the need for phosphine dissociation which is required with Wilkinson ' s catalyst.Interestingly, cationic diene iridium complexes of general formula [Ir(COD)(PR 3 ) 2 ] + (COD = 1,5 -cyclo -octadiene), mainly developed by Crabtree, may be even more active than the cationic diene rhodium complexes, particularly when dichloromethane ( DCM ) is used as solvent. The solvent is less coordinating and must be easily displaced by the substrates. Furthermore, its polarity favors the solubility of the ionic catalyst. As in the case of rhodium systems, [IrH 2 S 2 (PR 3 ) 2 ] + species can be observed by hydrogenation of the diene [3,4] . Another important discovery was the very active mixed ligand complex [Ir(COD)(py)(PCy 3 )] + (py = pyridine), usually known as Crabtree ' s catalyst, that in DCM as solvent effectively hydrogenates tetrasubstituted amido -alkenes [3] . The related benzonitrile (bzn) derivatives [Ir(COD)(bzn)(PR 3 )] + (PR 3 = PCy 3 or the chiral phosphines, neomenthyldiphenylphosphine or phenyl -( o -methoxyphenyl)methylphosphine) are also very active catalysts for the hydrogenation of prochiral didehydro amino acid derivatives [5] , although poor enantiomeric excess ( ee ) values are obtained with chiral monodentate phosphines. The effectiveness of the [Ir(COD)(L)(PR 3 )] + cations for

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Synthesis, Molecular Structure, and Reactivity of Iridium(I) and Iridium(III) Complexes Formed by Coordination and C−H Activation of the Substituted Arenes C₆H₅CH₂CH₂PiPr₂and C₆H₅OCH₂CH₂PtBu₂

Cited by 20 publications

References 12 publications

Rhodium(I) and Rhodium(III) Complexes Formed by Coordination and CH Activation of Bulky Functionalized Phosphanes

Rhodium(I) and Rhodium(III) Complexes Formed by Coordination and CH Activation of Bulky Functionalized Phosphanes

Sequential Reactions of Alkynes on an Iridium(III) Single Site

Dihydrido Iridium Triisopropylphosphine Complexes: From Organometallic Chemistry to Catalysis

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