1,721,195 research outputs found
New diruthenium vinyliminium complexes from the insertion of alkynes into bridging aminocarbynes
No full textPrimary alkynes R′CCH [R′ = Me3Si, Tol, CH2OH, CO2Me, (CH2)4CCH, Me] insert intothe metal–carbon bond ofdiruthenium μ-aminocarbynes [Ru2{μ-CN(Me)(R)}(μ-CO)(CO)(MeCN)(Cp)2][SO3CF3] [R = 2,6-Me2C6H3 (Xyl), 1a; CH2Ph (Bz), 1b; Me, 1c] to give thevinyliminiumcomplexes [Ru2{μ-η1:η3-C(R′)CHCN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Xyl, R′ = Me3Si, 2a; R = Bz, R′ = Me3Si, 2b; R = Me, R′ = Me3Si, 2c; R = Xyl, R′ = Tol, 3a; R = Bz, R′ = Tol, 3b; R = Bz, R′ = CH2OH, 4; R = Bz, R′ = CO2Me, 5a; R = Me, R′ = CO2Me, 5b; R = Xyl, R′ = (CH2)4CCH, 6; R = Xyl, R′ = Me, 7a; R = Bz, R′ = Me, 7b; R = Me, R′ = Me, 7c]. The related compound [Ru2{μ-η1:η3-C[C(Me)CH2]CHCN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3], (9) is better prepared by reacting [Ru2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(Cl)(Cp)2] (8) with AgSO3CF3 in the presence of HCCC(Me)CH2 in CH2Cl2 at low temperature.In a similar way, also secondary alkynes can be inserted to give thenewcomplexes [Ru2{μ-η1:η3-C(R′)C(R′)CN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = Bz, R′ = CO2Me, 11; R = Xyl, R′ = Et, 12a; R = Bz, R′ = Et, 12b; R = Xyl, R′ = Me, 13). The reactions of2–7, 9, 11–13 with hydrides (i.e., NaBH4, NaH) have been also studied, affording μ-vinylalkylidene complexes [Ru2{μ-η1:η3-C(R′)C(R′′)C(H)N(Me)(R)}(μ-CO)(CO)(Cp)2] (R = Bz, R′ = Me3Si, R′′ = H, 14a; R = Me, R′ = Me3Si, R′′ = H, 14b; R = Bz, R′ = Tol, R′′ = H, 15; R = Bz, R′ = R′′ = Et, 16), bis-alkylidene complexes [Ru2{μ-η1:η2-C(R′)C(H)(R′′)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (R′ = Me3Si, R′′ = H, 17; R′ = R′′ = Et, 18), acetylide compounds [Ru2{μ-CN(Me)(R)}(μ-CO)(CO)(CCR′)(Cp)2] (R = Xyl, R′ = Tol, 19; R = Bz, R′ = Me3Si, 20; R = Xyl, R′ = Me, 21) or the tetranuclear species [Ru2{μ-η1:η2-C(Me)CCN(Me)(Bz)}(μ-CO)(CO)(Cp)2]2 (23) depending on the properties ofthe hydride and the substituents on thecomplex. Chromatography of21 on alumina results in its conversion into [Ru2{μ-η3:η1-C[N(Me)(Xyl)]C(H)CCH2}(μ-CO)(CO)(Cp)2] (22). The crystal structures of2a[CF3SO3] · 0.5CH2Cl2, 12a[CF3SO3] and 22 have been determined by X-ray diffraction studies
Synthesis of new mono-, di- and polynuclear iron compounds via deprotonation of diiron m-vinyliminium complexes
No full textAddition of protic nucleophiles to alkynyl methoxy carbene ligands in diiron complexes
Full text linkDifferent protic nucleophiles (i.e. Ph2C=NH, PhSH, MeCO2H, PhOH) can be added to the C equivalent to C bond of [Fe-2{mu-CN(Me)(Xyl)}-(mu-CO)(CO){C(OMe)C equivalent to CTol}(CP)(2)][SO3CF3] (1), affording new diiron alkenyl methoxy carbene complexes. The additions of Ph2C=NH and MeCO2H are regio and stereoselective, resulting in the formation of the 5-aza-1-metalla-1,3,5-hexatriene [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO){C-alpha(OMe)C beta H=C-gamma(Tol)(N=CPh2)}(CP)(2)][SO3CF3](2), and the 2-(acyloxy)alkenyl methoxy carbene complex [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO){C-alpha(OMe)C beta H=C-gamma(Tol)OC(O)Me)}(CP)(2)][CF3SO3] (5); the E isomer of the former and the Z of the latter are formed exclusively. Conversely, the addition of PhSH is regio but not stereoselective; thus, both the E and Z isomers of [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO){C-alpha(OMe)C beta H=C-gamma(Tol)(SPh)}(CP)(2)][SO3CF3](3) are formed in comparable amounts. Compounds 3 and 5 are demethylated upon chromatography through Al2O3, resulting in the formation of the acyl complexes [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO){C-alpha(O)C beta H=C-gamma(Tol)(SPh)}(Cp)(2)](4) and [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO){C-alpha(O)C beta H=C-gamma(Tol)OC(O)Me}(CP)(2)](6), respectively, both with a Z configured C-beta=C-gamma bond. Finally, the reaction of 1 with PhOH proceeds only in the presence of an excess of Et3N affording the 2-(alkoxy)alkenyl acyl complex [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO){C-alpha(O)C beta H=C-gamma(Tol)(OPh)}(CP)(2)](7). The crystal structures of 4 center dot CH2Cl2 and 7 center dot 0.5CH(2)Cl(2) have been determined by X-ray diffraction experiments
Trapping hyghly reactive deprotonated vinyiliminium ligand in diiron complexes
No full textVedi Libro Abstrac
Ligand Control in Multihaptotropic O-Indenyl Rhenium Systems. Experimental and Theoretical Study
No full textThe synthesis of a novel class of alcohol- and ether-functionalized indenyl ligands, focusing on the haptotropic rearrangements of the hybrid O-indenyl rhenium species, is herein described. η1-
Indx OMeRe(CO)5 (12x) and η3-IndxOMeRe(CO)4 (13x, x=a, d) [IndaOMe=C9H6CH2CH(Me)OMe, 1a; Indd OMe=C9H6CH(CH2)3CHOMe, 1da] are examples of σ and allylic intermediates in the Cp
substitution. The tuning of stereoelectronic effects of the functionalized alkyl chain or the coordinating solvent (MeCN, THF) allows the study of the relative stabilities of the intercepted solvento species η5-Indb OMeRe(CO)2(NCMe), 14b, η5-Indc OMeRe(CO)2(THF), 15c, or the chelate [η5:k1-OIndb, c ORe(CO)2], 16b,c {Indb OMe=[C9H6CH2CH(Ph)OMe]-, 4b; Indc OMe=[C9H6CH(Ph)CH2OMe]-, 4c}. DFT calculations reported on some of the IndO systems have been compared with those of smaller (CpO) 5a or larger (Flua O) 10a congeners, confirming the experimental findings. As peculiar examples of the underrepresented low-valent rhenium alkoxy species, the isolation of k1-O-HIndxORe(CO)5 [x=a, b] is also reporte
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