Molecular Modeling of Ruthenium Alkylidene Mediated Olefin Metathesis Reactions. DFT Study of Reaction Pathways

Abstract

Three possible reaction pathways have been studied for the Cl 2 (PMe 3 ) 2 RudCH 2 and Cl 2 (PCy 3 ) 2 RudCH 2 (Cy ) cyclohexyl) mediated metathesis reaction of propylene by quantummechanical DFT calculations. It was found that in all cases the metathesis reaction proceeds via dissociative substitution of a phosphine ligand with propylene, giving a monophosphine complex. This tendency increases with ligand volume, and in the case of smaller PMe 3 groups it is the entropy contribution to the reaction energetics that causes the monophosphine complex to participate in the metathesis reaction, according to the modeling data.

Novel Ruthenium(II) N‐Heterocyclic Carbene Complexes as Catalyst Precursors for the Ring‐Opening Metathesis Polymerization (ROMP) of Enantiomerically Pure Monomers: X‐ray Structures, Reactivity, and Quantum Chemical Considerations

“…The B3LYP/LACVP* method has already been successfully used in many studies. [45][46][47][48] To prove the ability of this method, the calculated molecular structure of precatalyst 3 was compared with its X-ray structure.…”

A comparative quantum chemical study of the ruthenium catalyzed olefin metathesis

“…22,36,38 For reasons of computational cost, most of the previous computational investigations on the olefin-metathesis were restricted to B3-LYP calculations employing small double-ζ AO basis sets. 42,48,49,54 Vyboishchikov et al 51 additionally presented CCSD(T) results obtained with a double-ζ basis set for some of the reacting species. Because the application of too small AO basis sets often leads to unreliable results (for a detailed discussion see e.g.…”

Ruthenium‐Based NHC‐Arene Systems as Ring‐Opening Metathesis Polymerisation Catalysts

“…Cross metathesis (CM), [7,8] ringclosing metathesis (RCM), [9] ring-opening metathesis polymerisation (ROMP) [10] and acyclic diene metathesis polymerisation (ADMET), [11] illustrate the versatility of the olefin metathesis reaction. Thanks to the continuous improvement of its initiators and a sharpened comprehension of its reaction mechanism, [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] the olefin metathesis transformation has been upgraded to a very practical, efficient and flexible synthetic methodology. Olefin metathesis now allows cleaner, more efficient and less expensive industrial production of polymers, fine chemicals, pesticides and pharmaceutical intermediates.…”