Reactions of Os3(CO)12 with carboxylic acids in a microwave reactor; synthesis of Os2(benzoate)2(CO)6, a dinuclear osmium(I) compound with aromatic carboxylate ligands

Kinetic and Computational Analysis of CO Substitution in a Dinuclear Osmium Carbonyl Complex: Intersection between Dissociative and Dissociative-Interchange Mechanisms

“…Upon exposing a toluene solution of complex 1 to an atmosphere of 99% 13 C enriched carbon monoxide at 50 °C for about an hour, the 13 C NMR spectrum indicated the axial CO groups are selectively enriched in 13 CO, with no apparent CO exchange occurring at the equatorial sites (Figure B). This observation is consistent with a weaker Os–C ax bond compared to that of Os–C eq , where the bond distances are 1.983(4) Å and 1.877(4) Å, respectively . Similar changes are noted in the infrared spectra in the CO region when 13 CO is added to a toluene solution of complex 1 .…”

“…Such substitution reactions of equatorial CO ligands are even slower. In 1987, Deeming and co-workers showed that the axial CO ligands in randomly 13 CO enriched Os 2 (μ-O 2 CCH 3 ) 2 (CO) 8 were readily substituted by acetonitrile to afford Os 2 (μ-O 2 CCH 3 ) 2 (CO) 4 (MeCN) 2. 12 Ultimately, the acetonitrile ligands were displaced by 12 CO to provide a complex specifically 13 CO labeled in positions trans to the acetate ligands.…”

Diruthenium tetracarbonyl complexes of sawhorse-type

“…In this context we examined compounds of the formula [Ru 2 (m-O 2 CR) 2 (CO) 4 ] (R ¼ t Bu) whereas the corresponding complex with R ¼ 1-adamantyl (Ad) was described recently [2]. Compound [Ru 2 (m-O 2 CAd) 2 (CO) 4 ] was reported to be a deep purple solid, however the exact molecular structure in the solid of this material could not be elucidated to date. We used the synthetic protocol for the preparation of the latter compound and investigated the reaction of [Ru 3 (CO) 12 ] with pivalic acid ( t BuCOOH) under similar conditions.…”

“…Relatively few is known on related osmium compounds which result from the reaction of [Os 3 (CO) 12 ] with carboxylic acids. Recently an improved synthesis of similar compounds [Os 2 (m-O 2 CR) 2 (CO) 6 ] (R ¼ H, Ph) was described [4] which exhibit also a sawhorse-type dimetal core. Here we report the synthesis and reactions of [{Ru 2 (m-O 2 C t Bu) 2 (CO) 4 } n ] (1) whereas the exact molecular structure of solid 1 remains unknown to date.…”

“…Calcd for C 24 H 28 N 2 O 8 Ru 2 (674.63): C, 42.73; H, 4.18; N, 4.15. Found: C, 43.00; H, 4.29; N,4.02%. IR (solid, cm À1 ): n(CO):2010vs, 1956m, 1927vs, 1920sh, n(m-OOC): 1558vs, 1428s.…”