Insertion and C–C coupling processes in reactions of the unsaturated hydride [W2Cp2(H)(μ-PCy2)(CO)2] with alkynes

Alvarez, M. Ángeles; Garcı́a, M. Esther; García‐Vivó, Daniel; Ruiz, Miguel A.; Vega, M. Fernanda

doi:10.1039/c5dt04724b

Cited by 9 publications

(4 citation statements)

References 49 publications

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“…We propose that isomers A and B display the same μ-κ 1 :η 2 coordination mode of the nitrosomethane ligand, with major isomer A corresponding to the structure found in the solid state for nitroxyl complex 3a and isomer B being obtained by just exchanging κ 1 and η 2 bindings of the bridging ligand between metal atoms (Chart ). We note that this is an isomerism previously found in alkenyl-bridged complexes of type [M 2 Cp 2 (μ-PCy 2 )(μ-κ 1 :η 2 -CRCH 2 )(NO) 2 ] (M= Mo, W), which are structurally related to complexes 4 .…”

Section: Resultssupporting

confidence: 69%

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂] (M = Mo, W)

et al. 2018

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The title complexes (1a,b) were prepared in two steps by first reacting the hydrides [M2Cp2(-H)(-PCy2)(CO)4] with [NO](BF4) in the presence of Na2CO3 to give dinitrosyls [M2Cp2(-PCy2)(CO)2(NO)2](BF4), which were then fully decarbonylated upon reaction with NaNO2 at 323 K. An isomer of the Mo2 complex having a cisoid arrangement of the terminal ligands (cis-1a) was prepared upon irradiation of toluene solutions of 1a with visible-UV light at 288 K. The structure of these trinitrosyl complexes was investigated using X-ray diffraction and density functional theory (DFT) calculations, these revealing a genuine pyramidalization of the bridging NO that might be associated in part to an increase of charge at the N atom, and also anticipated a weakening of the NO bond upon reaction with bases or reducing reagents. Complexes 1a,b reacted with [FeCp2](BF4) to give first the radicals [M2Cp2(-PCy2)(-NO)(NO)2](BF4) according to CV experiments, which then underwent H-abstraction to yield the nitroxyl-bridged complexes [M2Cp2(-PCy2)(- 1 : 2-HNO)(NO)2](BF4), alternatively prepared upon protonation with HBF4•OEt2. The novel coordination mode of the nitroxyl ligand in these products was thermodynamically favored over its tautomeric hydroximido form, according to DFT calculations, and similar nitrosomethane-bridged cations [M2Cp2(-PCy2)(- 1 : 2-MeNO)(NO)2] + were prepared by reacting 1a,b with CF3SO3Me or [Me3O]BF4. Complexes 1 reacted with M(Hg) (M = Zn, Na) in tetrahydrofuran to give the amido-bridged derivatives [M2Cp2(-PCy2)(-NH2)(NO)2] with retention of stereochemistry, a transformation also induced by using mild O-atom scavengers such as CO and phosphites in the presence of water. In the absence of water, phosphites accomplished a deoxygenation of the bridging NO of the Mo2 complexes to yield the phosphoraniminato-bridged derivatives [Mo2Cp2(-PCy2){-NP(OR)3}(NO)2] (R = Et, Ph), also with retention of stereochemistry.

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Section: Resultssupporting

confidence: 69%

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂] (M = Mo, W)

et al. 2018

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“…0.04 Å longer than the corresponding lengths in the mentioned carboxylate-substituted alkenyl complexes, likely reflecting the bulkier nature of the phosphanyl ligand (compared to PCy 2 ) in compounds 3 . We note that the trans -dicarbonyl geometry exhibited by these complexes has been structurally characterized also for the carboxylate-substituted alkenyl complexes [W 2 Cp 2 (μ–κ 2 C,O :η 2 C,C -CRCHR)(μ-PCy 2 )(CO) 2 ] and [Mo 2 Cp 2 {μ–κ 2 C,O :η 2 C,C -CRCHR)(μ-X)(CO) 2 ] (X = PPh 2 , S i Pr; R = CO 2 Me) and for the benzoylalkenyl complex [Mo 2 Cp 2 {μ–κ 2 C,O :η 2 C,C -CHCH(C(O)Ph)}(μ-PPh 2 )(CO) 2 ] …”

Section: Resultsmentioning

confidence: 82%

“…0.04 Å longer than the corresponding lengths in the mentioned carboxylate-substituted alkenyl complexes, likely reflecting the bulkier nature of the phosphanyl ligand (compared to PCy 2 ) in compounds 3. We note that the trans-dicarbonyl geometry exhibited by these complexes has been structurally characterized also for the carboxylatesubstituted alkenyl complexes 19 and [Mo 2 Cp 2 {- 2 C,O : 2 C,C -CRCHR)(-X)(CO) 2 ] (X= PPh 2 , S i Pr; R = CO 2 Me), 20 and for 21 The geometrical parameters within the phosphanyl ligand of compounds cis-3 and trans-3 are comparable to those observed for the hydride complex 4, 8,9 and deserve no comment. However, the interatomic lengths involving the bridging hydrocarbon group show some differences when compared to those measured in the alkenyl complexes mentioned above.…”

Section: Chartmentioning

confidence: 99%

Divergent Reactivity of a Phosphinidene-Bridged Dimolybdenum Complex Toward 1-Alkynes: P–C, P–H, C–C, and C–H Couplings

et al. 2017

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The ability of complex [Mo 2 Cp 2 {μ-P(2,4,6-C 6 H 2 t Bu 3 )}(CO) 4 ] to promote P−C and subsequent coupling processes has been analyzed by examining reactions with alkynes. The title compound reacted at room temperature with different terminal alkynes HCCR under visible-UV light irradiation to give, in a selective way, the corresponding phosphapropenediyl derivatives [Mo 2 Cp 2 (μ−κ 1 C :η 3 C,C,P -CRCHPR*)(CO) 4 ] for R groups of varied electron-withdrawing nature, but low to medium size, such as Pr, CO 2 Me, and p-tol. These products follow from formal insertion of the alkyne into one of the Mo-phosphinidene bonds in the parent compound, with selective P−C coupling to the terminal carbon of the alkyne. In contrast, when R was the bulky t Bu group, the corresponding photochemical reactions yielded a mixture of the cis and trans isomers of the phosphanyl-and formylalkenyl-bridged complex [Mo 2 Cp 2 {μ−κ 2 C,O :η 2 C,C -CHC( t Bu)C(O)H}{μ-P(CH 2 CMe 2 )-C 6 H 2 t Bu 2 }(CO) 2 ], which follow from a complex reaction sequence involving an H−C(sp 3 ) bond cleavage along with different P−C, P−H, C−C, and C−H bond formation steps. Density functional theory calculations were carried out to rationalize the preceding observations and suggested that an isomer of the parent complex displaying a bent terminal phosphinidene ligand might be involved in all the above photochemical reactions.

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“…We have previously reported the preparation of complexes very similar to 5 through the reaction of the unsaturated hydrides [M 2 Cp 2 (μ-H)(μ-PCy 2 )(CO) 2 ] with HCC( p -tol) (M = Mo and W; p -tol =4-C 6 H 4 Me) . Spectroscopic data for 5 (Table and Experimental Section) are indeed very similar to those of the mentioned p -tol-substituted compounds and will not be discussed in detail.…”

Section: Resultsmentioning

confidence: 99%

C–C and C–N Couplings in Reactions of the Benzylidyne-Bridged Complex [Mo₂Cp₂(μ-CPh)(μ-PCy₂)(CO)₂] with Small Unsaturated Organics

et al. 2016

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The ability of the title compound to promote C–C coupling processes has been analyzed by examining its reactions with diazoalkanes, alkynes, and other unsaturated organic molecules. The title compound reacted with N2CPh2 at room temperature to give a mixture of ketenyl complex [Mo2Cp2{μ-κ1:η2-C(Ph)CO}(μ-PCy2)(CO)(κ1-N2CPh2)] and carbyne complex [Mo2Cp2(μ-CPh)(μ-PCy2)(CO)(κ1-N2CPh2)], products which can be converted into each other by addition/removal of CO, respectively. In contrast, denitrogenation took place rapidly in analogous reactions with diazomethane and benzylazide at room temperature, to yield, respectively, the corresponding alkenyl [Mo2Cp2{μ-κ1:η2-C(Ph)CH2}(μ-PCy2)(CO)2] and iminoacyl [Mo2Cp2{μ-C(Ph)NCH2Ph}(μ-PCy2)(CO)2] derivatives, following from selective C–C and C–N couplings. The title compound reacted at 333 K with methyl propiolate to give the corresponding propenylylidene derivative [Mo2Cp2{μ-κ2:η3-CPhCHC(CO2Me)}(μ-PCy2)(CO)2], as a result of selective coupling of the carbyne ligand to the terminal carbon of the alkyne. A related complex could be obtained when using the internal alkyne dimethyl acetylenedicarboxylate.

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Insertion and C–C coupling processes in reactions of the unsaturated hydride [W₂Cp₂(H)(μ-PCy₂)(CO)₂] with alkynes

Abstract: The title compound reacted with p-tolylacetylene at room temperature to give the 32-

Cited by 9 publications

References 49 publications

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂] (M = Mo, W)

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂] (M = Mo, W)

Divergent Reactivity of a Phosphinidene-Bridged Dimolybdenum Complex Toward 1-Alkynes: P–C, P–H, C–C, and C–H Couplings

C–C and C–N Couplings in Reactions of the Benzylidyne-Bridged Complex [Mo₂Cp₂(μ-CPh)(μ-PCy₂)(CO)₂] with Small Unsaturated Organics

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Insertion and C–C coupling processes in reactions of the unsaturated hydride [W2Cp2(H)(μ-PCy2)(CO)2] with alkynes

Abstract: The title compound reacted with p-tolylacetylene at room temperature to give the 32-

Cited by 9 publications

References 49 publications

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M2Cp2(μ-PCy2)(μ-NO)(NO)2] (M = Mo, W)

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M2Cp2(μ-PCy2)(μ-NO)(NO)2] (M = Mo, W)

Divergent Reactivity of a Phosphinidene-Bridged Dimolybdenum Complex Toward 1-Alkynes: P–C, P–H, C–C, and C–H Couplings

C–C and C–N Couplings in Reactions of the Benzylidyne-Bridged Complex [Mo2Cp2(μ-CPh)(μ-PCy2)(CO)2] with Small Unsaturated Organics

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Insertion and C–C coupling processes in reactions of the unsaturated hydride [W₂Cp₂(H)(μ-PCy₂)(CO)₂] with alkynes

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂] (M = Mo, W)

N–O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂] (M = Mo, W)

C–C and C–N Couplings in Reactions of the Benzylidyne-Bridged Complex [Mo₂Cp₂(μ-CPh)(μ-PCy₂)(CO)₂] with Small Unsaturated Organics