Direct Arylation of a Cluster-Bound Alkyne Ligand with Benzene

Abstract

Treatment of a triruthenium complex having μ 3methylidyne and μ 3 -propyne ligands, (Cp*Ru) 3 (μ 3 -CH)(μ 3 -η 2 -HCCMe)(μ-H) 2 (6), with benzene results in arylation of the propyne ligand via the C-H bond activation of benzene to yield the μ 3 -phenylmethylacetylene complex (Cp*Ru) 3 (μ 3 -CH)(μ 3η 2 :η 2 (^)-PhCCMe) ( 7). An X-ray diffraction study of 7 clearly established that regiospecific arylation occurred at the terminal position of the propyne ligand.

Flexidentate Coordination Behavior and Chemical Non‐Innocence of a Bis(1,3‐Diphosphacyclobutadiene) Sandwich Anion

“…[17] The C1ÀC2 distance of the bent alkynel igand is 1.34 (1) ,t he tert-butyl substituents enclose CÀCÀCa ngles of 141.1(8)8 and 144.8(8)8,r espectively.S imilar structuralp arameters are found in other alkyne-bridged diruthenium complexes. [18] The Ru1ÀRu2 distance of 2.6985(8) is 0.2 larger than the sum of covalent radii. [15] DFT optimization (BP86-D3BJ/def2-TZVP level of theory,s ee the Supporting Information for details) reproduced the molecular structure of 6 very well, whereas attempted optimizations of the isomeric bis(phosphaalkyne)c omplex [(Cp*Ru) 2 (m,h 2 -PCtBu) 2 ]( 6')a lso converged at 6.T his seems to indicate that 6' is not am inimum on the potential energy hypersurface.…”

“…The cyclic voltammogram of 5 (THF/[nBu 4 N]PF 6 ,F igure S42, Supporting Information) features two reversible redox events at E1 = 2 = À0.46 and À2.10 V( vs. Fc/Fc + + ), which may tentatively be assigned to the reversible oxidation and reduction of the complex, respectively.T he cyclic voltammogram of 6 (THF/ [nBu 4 N]PF 6 ,F igure S43) shows two successive reversible oxidation waves at E1 = 2 = À0.63 and 0.00 V( vs. Fc/Fc + + ). It is noteworthy that anions of type A show only one reversible oxidation event (E1 = 2 = À0.73 Vv s. Fc/Fc + for [K( [18]crown-6)(thf) 2 {Co(P 2 C 2 tBu 2 ) 2 }]). [7] Reactiono f[K(thf) 2 {Co(P 2 C 2 tBu 2 ) 2 }] with [RhCl(cod)] 2 We continued our investigation by reacting [K(thf) 2 {Co(P 2 C 2 R 2 ) 2 }] (R = tBu, Ad) with [RhCl(cod)] 2 (0.5 equivalents, cod = 1,5-cyclooctadiene).…”

“…It is noteworthy that anions of type A show only one reversible oxidation event (E1 = 2 = À0.73 Vv s. Fc/Fc + for [K( [18]crown-6)(thf) 2 {Co(P 2 C 2 tBu 2 ) 2 }]). It is noteworthy that anions of type A show only one reversible oxidation event (E1 = 2 = À0.73 Vv s. Fc/Fc + for [K( [18]crown-6)(thf) 2 {Co(P 2 C 2 tBu 2 ) 2 }]).…”

Binuclear Aromatic C−H Bond Activation at a Dirhenium Site

“…[1,2] Low-valent metal atoms in complexes have been found to be very effective agents for performing CÀH bond cleavage. [5] In recent studies,w ed iscovered af acile C À Hb ondforming process leading to benzene formation by the NCMeinduced reductive elimination of the bridging phenyl ligand and the bridging hydrido ligand from the complex [Re 2 -(CO) 8 (m-H)(m-h 1 -C 6 H 5 )] (1)t oyield the complex [Re 2 (CO) 8 -(NCMe) 2 ][Equation (1).] [5] In recent studies,w ed iscovered af acile C À Hb ondforming process leading to benzene formation by the NCMeinduced reductive elimination of the bridging phenyl ligand and the bridging hydrido ligand from the complex [Re 2 -(CO) 8 (m-H)(m-h 1 -C 6 H 5 )] (1)t oyield the complex [Re 2 (CO) 8 -(NCMe) 2 ][Equation (1).]…”

Binuclear Aromatic C−H Bond Activation at a Dirhenium Site

“…[1][2][3][4] Examples involving activation of aromatic C À Hb onds by polynuclear metal complexes are rare. [5] In recent studies,w ed iscovered af acile C À Hb ondforming process leading to benzene formation by the NCMeinduced reductive elimination of the bridging phenyl ligand and the bridging hydrido ligand from the complex [Re 2 -(CO) 8 (m-H)(m-h 1 -C 6 H 5 )] (1)t oyield the complex [Re 2 (CO) 8 -(NCMe) 2 ][Equation (1).] [6] We have now found that 1 is equally capable of performing facile activation of aromatic CÀHbonds and can be used as ar eagent for the formation of new dirhenium complexes containing bridging aryl and bridging hydrido ligands.T he reaction of 1 with N,N-diethylaniline yielded benzene and the new dirhenium complex [Re 2 (CO) 8 (m-H)(m-h 1 -C 6 H 4 NEt 2 )] (2)i n6 1% yield after 5.5 hours at 50 8 8C[Equation (2)].…”