Syntheses and Characterization of Ruthenium Complexes Containing a Doubly Linked Dicyclopentadienyl Ligand and Acetonitrile Ligands

Abstract

The reaction of a mixture of isomers of 4,4,8,8-tetramethyl-tetrahydro-s-indacene (1) with Ru 3 -(CO) 12 afforded cis-{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (CO) 4 , (2) in 68% yield. Reaction of 2 with Br 2 gave cis-{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (CO) 4 Br 2 (3) in 88% yield. Reaction of 3 with AgOTf yields cis-[{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (CO) 4 (μ-Br)][OTf] (4), while reaction of 3 with Me 3 NO and AgOTf yields cis-[{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (CO) 2 (MeCN) 2 (μ-Br)][OTf] (5). Reaction of 3 under more forcing conditions with AgOTf in MeCN gave cis-[{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (CO) 2 (MeCN) 4 ][OTf] 2 (6), while a MeCN/C 6 H 6 solvent combination afforded cis-[{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (η 6 -C 6 H 6 ) 2 ][OTf] 2 (7) in a 64% yield. Removal of the benzene ligands in 7 can be accomplished by first adding Hto the coordinated benzene ligands to afford cis-{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (η 5 -C 6 H 7 ) 2 (10). Subsequent protonation of 10 in MeCN afforded [cis-{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }Ru 2 (MeCN) 6 ][OTf] 2 (8) in 88% yield. Structural data for 4, 5, 7, and 10 are reported.

Reactivity of Methyl Diruthenium Complexes with CO and Bipyridine Ligands

“…We have assigned the largest peak at −79.3 ppm as being the unbound triflate anion in 2, while the bound triflate in 2′ is assigned to the peak at −77.1 ppm. Bullock and co-workers have reported the 19 F resonance for the bound triflate in Cp*Ru(CO) 2 OTf at −77.6 ppm. 6b The peak at −77.0 ppm remains unassigned right now, but computational modeling of 2′ shows that there are two different configurations for the bound triflate, with one conformer having the triflate group pointed toward the other ruthenium metal center, 2′ "in", while the other conformer has the triflate group pointed away from the other ruthenium, 2′ "out" (Figure 1 and Supporting Information, Figure S23).…”

“…1 H and 13 C NMR chemical shifts are given relative to the residual proton or 13 C solvent resonances. 19 F NMR spectra are referenced to CF 3 COOH (−76.55 ppm) in CD 2 Cl 2 . NMR spectra were recorded at room temperature (20−25 °C) unless otherwise noted.…”

“…13 C{ 1 H} NMR (100 MHz, CD 2 Cl 2 ) δ 198.29 (CO), 198.25 (CO), 115.8 (quat C), 115.6 (quat C), 107.0 (CH), 86.8 (CH), 78.9 (CH), 73.8 (CH), 35.7 (quat C), 32.7 (CH 3 ), 32.6 (CH 3 ), − 17.2 (CH 3 ). 19 F NMR (376 MHz, CD 2 Cl 2 ) δ − 79.33 (s). IR (KBr) ν (CO) (cm −1 ) 2062 (vs), 2010 (vs) Anal.…”

“…1 H NMR (400 MHz, CD 2 Cl 2 ): δ 5.69 (t, 3 J HH = 2.9 Hz, 1H), 5.24 (d, 3 J HH = 2.9 Hz, 2H), 5.07 (t, 3 J HH = 2.9, 1H), 5.02 (d, 3 J HH = 2.9 Hz, 2H), 1.57 (s, 6H), 1.53 (s, 6H), 0.37 (s, 3H). 19 F NMR (376 MHz, CD 2 Cl 2 ) δ − 77.09 (s).…”

“…Na­[B­(Ar F ) 4 ] and [H­(Et 2 O) 2 ]­[B­(Ar F ) 4 ] were prepared as previously reported . [ cis -{(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }­Ru 2 (κ 2 -(4,4′-di- tert -butyl)-2,2′-bipyridine) 2 (CH 3 CN) 2 ]­[OTf] 2 and cis- {(η 5 -C 5 H 3 ) 2 (CMe 2 ) 2 }­Ru 2 (CO) 4 were prepared as previously reported. , …”