Unusual η¹‐Coordinated Alkyne and Alkene Complexes

Abstract

This mechanistic study demonstrates that an unusual h 1 -coordinated alkyne complex is criticalf or the 1-pentyne 1,1-diboration reaction. The comparatives tudies suggest the "pull-push" antagonistic effect arising from Lewis acidity and steric congestion as the reason for the existence of h 1 -coordinated alkyne complexes. Analogous h 1 -coordinated alkene complexes are also predicted and seem to be promising for their applicationt ot he important olefin polymerization reaction.Scheme1.Synthesis of 1,1-and 1,2-diboration of 1-pentyne by Erker and co-workers. [8] [a] Dr.

Carbonylic-Carbon-Centered Mechanism for Catalytic α-Methylation

“…Finally, the CC hydrogenation product C6a is achieved, and the α-methylation of propiophenone is completed. It should also be noted that no coordination of CC bond to the metal atom is involved for the enone CC hydrogenation in this study, although the Dewar–Chatt–Duncanson η 2 -coordination model is generally reported in the previous studies on the CC activations in alkene hydrogenations. − Actually, in the whole reaction, the carbonyl ligand serves as a catalytic center.…”

“…In accordance with our previous theoretical studies on homogeneous hydrogenation and dehydrogenation reactions, − we adopted the DFT ωB97X-D method in this study using the Gaussian 09 program . Geometries were optimized in a methanol solution using the BS-I basis sets, where the 6-311G­(d,p) basis sets were used for nonmetal atoms, and the SDD basis sets with effective core potentials were used for the Mn, Cs, and Ru atoms. − The single-point energy refinements were further performed with the BS-II basis sets, where the def2-TZVPP basis sets were used for all atoms. , Thermal corrections and entropy contribution to the Gibbs free energy were obtained with the ωB97X-D/BS-I methods.…”

Theoretical Design of a Catalyst with Both High Activity and Selectivity in C–H Borylation

“…In accordance with previous computational studies on borylation reactions catalyzed by transition-metal complexes, − all calculations were carried out by the DFT method with the ωB97X-D method using the Gaussian 09 program . In the geometry optimization, the SDD basis set is used for the Ir center and 6-311G­(d,p) , basis sets are used for all of the other atoms .…”

Synthesis of Alkenylboronates from N-Tosylhydrazones through Palladium-Catalyzed Carbene Migratory Insertion

“…DIA shows that the difference in total distortion energy between TSC4–5 E and TSC4–5 Z is small (16.83 vs 16.82 kcal/mol), and the lower energy of TSC4–5 E compared with TSC4–5 Z is mainly caused by the stronger interaction between the metal complex and monomer moiety (−36.89 vs −33.95 kcal/mol). The interaction between the organometallic complex and unsaturated hydrocarbons could be described by the Dewer–Chatt–Duncanson model. − The metal–ligand interaction could be considered to arise from the electron pair delocalization, in which a donation of olefin π-electrons into the metal and back-donation from the metal into the olefin π* orbital occur. Meanwhile, the natural bond orbital (NBO) analysis shows the acceptor–donor interactions between the Pd–H bond and C1C2 bond.…”