An ab initio investigation of σ-bond metathesis and insertion reactions of acetylene with Cl2ZrH+ and Cl2ZrCH3+

✍ Scribed by Isabella Hyla-Kryspin; Sandro Johannes Silverio; Shuqiang Niu; Rolf Gleiter

• Book ID: 104423130
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 840 KB
• Volume: 115
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(96)00100-8

✦ Synopsis

All-electron RHF and RMP2 ab initio calculations with split-valence basis sets of double-and triple-t quality have been used to study reaction paths for the reaction of acetylene (1) with the model compounds Cl 2 ZrH + (2) and Cl 2 ZrCH : (3). At the RMP2//RHF level the acetylide-complex formation reaction is calculated to have a barrier of 15.8 (2), 20.8 (3) kcal/mol with respect to complexed acetylene and to be 44.4 (21, 18.9 (3) kcal/mol exothermic with respect to free acetylene. The transition states are four-membered cycles. The calculated energy barriers are greater than the theoretical values obtained for u-bond metathesis of acetylene with CI,ScR and Cp,ScR (R = H, CH,). The calculated energetics of the metathesis reaction path are compared with the theoretical values determined for the alternative insertion reaction of acetylene into Zr-H and Zr-C u bonds. The insertion reactions are kinetically and thermodynamically favoured over the corresponding metathesis reactions.