Synthesis and Dynamic Properties of a Triruthenium Complex Containing μ3-η2(∥)-Ethyne and μ3-Methylidyne Ligands: Equilibrium of an Ethyne–Hydrido Complex with a Nonclassical μ3-Vinyl Complex
摘要:
A triruthenium complex containing mu(3)-eta(2)(parallel to)-ethyne and mu(3)-methylidyne ligands, (CpRu)(3){mu(3)-eta(2)(parallel to)-HC CH}(mu(3)-CH)(mu-H)(2) (2a), was synthesized via the treatment of {Cp*Ru(mu-H)}(3)(mu(3)-H)(2) (3) (Cp* = eta(5)-C5Me5) with propene. In the low-temperature region, VT H-1 NMR spectra showed that complex 2a is in equilibrium with a nonclassical mu(3)-vinyl complex, (CpRu)(3)(mu(3)-eta(2):eta(2)-HC=CH2)(mu(3)-CH)(mu-H) (5a), which features an interaction between one of the beta-vinyl protons and a Ru center. The presence of the unusual 3c-2e interaction of the beta-C-H bond of the vinyl group is strongly supported by the small J(C-H) value (98 Hz) found for the beta-carbon as well as the small J(H-H) value for the a-vinyl proton. Treatment of the equilibrated mixture of phenyl-substituted complexes (CpRu)(3){mu(3)-eta(2)(parallel to)-HC CPh}(mu(3)-CH)(mu-H)(2) (2b) and (CpRu)(3)(mu(3)-eta(2):eta(2)-HC=CHPh)(mu(3)-CH)(mu-H) (5b) with tBuNC afforded a mu-styryl complex, (CpRu)(3)(mu-eta(2)-HC=CHPh)(mu(3)-CH)(mu-tBuNC)(mu-H) (6), while analogous treatment of 2a and 5a resulted in the formation of mu(3)-dimetalloallyl complex (CpRu)(3){mu(3)-eta(3)-CHCHCN(H)tBu}(mu(3)-CH)(mu-H) (7). These results imply that the coordinatively saturated mu(3)-eta(2)(parallel to)-alkyne-mu(3)-alkylidyne complex can generate a vacant site via the migration of a hydrido ligand onto an alkyne ligand to yield a mu-vinyl intermediate.
Synthesis and Dynamic Properties of a Triruthenium Complex Containing μ3-η2(∥)-Ethyne and μ3-Methylidyne Ligands: Equilibrium of an Ethyne–Hydrido Complex with a Nonclassical μ3-Vinyl Complex
摘要:
A triruthenium complex containing mu(3)-eta(2)(parallel to)-ethyne and mu(3)-methylidyne ligands, (CpRu)(3){mu(3)-eta(2)(parallel to)-HC CH}(mu(3)-CH)(mu-H)(2) (2a), was synthesized via the treatment of {Cp*Ru(mu-H)}(3)(mu(3)-H)(2) (3) (Cp* = eta(5)-C5Me5) with propene. In the low-temperature region, VT H-1 NMR spectra showed that complex 2a is in equilibrium with a nonclassical mu(3)-vinyl complex, (CpRu)(3)(mu(3)-eta(2):eta(2)-HC=CH2)(mu(3)-CH)(mu-H) (5a), which features an interaction between one of the beta-vinyl protons and a Ru center. The presence of the unusual 3c-2e interaction of the beta-C-H bond of the vinyl group is strongly supported by the small J(C-H) value (98 Hz) found for the beta-carbon as well as the small J(H-H) value for the a-vinyl proton. Treatment of the equilibrated mixture of phenyl-substituted complexes (CpRu)(3){mu(3)-eta(2)(parallel to)-HC CPh}(mu(3)-CH)(mu-H)(2) (2b) and (CpRu)(3)(mu(3)-eta(2):eta(2)-HC=CHPh)(mu(3)-CH)(mu-H) (5b) with tBuNC afforded a mu-styryl complex, (CpRu)(3)(mu-eta(2)-HC=CHPh)(mu(3)-CH)(mu-tBuNC)(mu-H) (6), while analogous treatment of 2a and 5a resulted in the formation of mu(3)-dimetalloallyl complex (CpRu)(3){mu(3)-eta(3)-CHCHCN(H)tBu}(mu(3)-CH)(mu-H) (7). These results imply that the coordinatively saturated mu(3)-eta(2)(parallel to)-alkyne-mu(3)-alkylidyne complex can generate a vacant site via the migration of a hydrido ligand onto an alkyne ligand to yield a mu-vinyl intermediate.