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Alkyne–alkenyl coupling at a diruthenium complex.
- Source :
- Dalton Transactions: An International Journal of Inorganic Chemistry; 11/7/2022, Vol. 51 Issue 41, p15703-15715, 13p
- Publication Year :
- 2022
-
Abstract
- Dimetallic complexes are suitable platforms for the assembly of small molecular units, and the reactivity of bridging alkenyl ligands has been widely investigated to model C–C bond forming processes. Here, we report the unusual coupling of an alkenyl ligand, bridging coordinated on a diruthenium scaffold, with a series of alkynes, revealing two possible outcomes. The diruthenium complex [Ru<subscript>2</subscript>Cp<subscript>2</subscript>(Cl)(CO)(μ-CO){μ–η<superscript>1</superscript>:η<superscript>2</superscript>-C(Ph)=CH(Ph)}], 2, was prepared in two steps from [Ru<subscript>2</subscript>Cp<subscript>2</subscript>(CO)<subscript>2</subscript>(μ-CO){μ–η<superscript>1</superscript>:η<superscript>2</superscript>-C(Ph)=CH(Ph)}]BF<subscript>4</subscript>, [1]BF<subscript>4</subscript>, in 69% yield. Then, the reaction of 2 with C<subscript>2</subscript>(CO<subscript>2</subscript>Me)<subscript>2</subscript>, promoted by AgCF<subscript>3</subscript>SO<subscript>3</subscript> in dichloromethane, afforded in 51% yield the complex [Ru<subscript>2</subscript>Cp<subscript>2</subscript>(CO)<subscript>2</subscript>{μ–η<superscript>3</superscript>:η<superscript>2</superscript>-C(Ph)CH(Ph)C(CO<subscript>2</subscript>Me)C(CO<subscript>2</subscript>Me)}]CF<subscript>3</subscript>SO<subscript>3</subscript>, [3]CF<subscript>3</subscript>SO<subscript>3</subscript>, containing a ruthenacyclopentene-based hydrocarbyl ligand. On the other hand, 2 reacted with other alkynes and AgX salts to give the butadienyl complexes [Ru<subscript>2</subscript>Cp<subscript>2</subscript>(CO)<subscript>2</subscript>{μ–η<superscript>3</superscript>:η<superscript>2</superscript>-C(R)CH(R′)C(Ph)C(Ph)}]X (R = R′ = H, [4]BF<subscript>4</subscript>; R = R′ = Me, [5]CF<subscript>3</subscript>SO<subscript>3</subscript>; R = R′ = Ph, [6]CF<subscript>3</subscript>SO<subscript>3</subscript>; R = Ph, R′ = H, [7]CF<subscript>3</subscript>SO<subscript>3</subscript>), in 42–56% yields. All products were characterized by IR and NMR spectroscopy, and by single crystal X-ray diffraction in the cases of 2, [3]CF<subscript>3</subscript>SO<subscript>3</subscript> and [6]BF<subscript>4</subscript>. DFT calculations highlighted the higher stability of [4–7]<superscript>+</superscript>-like structures with respect to the corresponding [3]<superscript>+</superscript>-like isomers. It is presumable that [3]<superscript>+</superscript>-like isomers initially form as kinetic intermediates, then undergo H-migration which is disfavoured in the presence of carboxylato substituents on the alkyne. Such hypothesis was supported by the computational optimization of the transition states for H-migration in the cases of R = R′ = H and R = R′ = CO<subscript>2</subscript>Me. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14779226
- Volume :
- 51
- Issue :
- 41
- Database :
- Complementary Index
- Journal :
- Dalton Transactions: An International Journal of Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 159809258
- Full Text :
- https://doi.org/10.1039/d2dt02866b