Four new Grubbs-type precatalysts [RuCl(H₂IMes)(O^N)(=CHPh)], where [O^N = α,α-diphenyl-(3-methylpyridin-2-yl)methanolato, α,α-diphenyl-(4-methylpyridin-2-yl)methanolato, α,α-diphenyl-(5-methylpyridin-2-yl)methanolato and α,α-diphenyl-(3-methoxypyridin-2-yl)methanolato] were synthesized and tested for their activity, stability and selectivity in the 1-octene metathesis reaction. Overall the precatalysts showed good activity and high stability for the metathesis of 1-octene at temperatures above 80 °C and up to 110 °C. Selectivities towards the primary metathesis products, i.e., 7-tetradecene and ethene, above 85% were obtained with all the precatalysts at 80 and 90 °C. High selectivities were also observed at 100 °C for the 4-Me- and 3-OMe-substituted precatalysts. With an increase in temperature an increase in isomerisation products and secondary metathesis products were observed with the latter reaching values >20% for the 3-OMe- and 3-Me-substituted precatalysts at 110 and 100 °C, respectively. All the precatalysts exhibits first-order kinetics at 80 °C with the 3-substituted precatalysts the slowest. The behaviour of the 3-substituted precatalysts can be attributed to electronic and steric effects associated with the adjacent bulky phenyl groups.

中文翻译：

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含半不稳定的α，α-二苯基-（单取代吡啶-2-基）甲醇配位体的Grubbs型钌亚烷基络合物催化线性烯烃复分解

四种新的Grubbs型预催化剂[RuCl（H ₂IMes）（O ^ N）（= CHPh）]，其中[O ^ N =α，α-二苯基-（3-甲基吡啶-2-基）甲醇，α，α-二苯基-（4-甲基吡啶-2-基）合成了α，α-二苯基-（5-甲基吡啶-2-基）甲醇和α，α-二苯基-（3-甲氧基吡啶-2-基）甲醇]，并测试了它们的活性，稳定性和选择性。 1-辛烯复分解反应。总体而言，该预催化剂在80°C至110°C的温度下对1-辛烯的复分解反应显示出良好的活性和较高的稳定性。在80和90°C下，所有预催化剂对主要复分解产物（即7-十四碳烯和乙烯）的选择性均达到85％以上。在100°C下，4-Me-和3-OMe取代的预催化剂也具有很高的选择性。随着温度的升高，观察到异构化产物和次级复分解产物的增加，对于3-OMe-和3-Me-取代的预催化剂，后者分别达到> 20％的值> 20％。所有的预催化剂在80°C时都表现出一级动力学，而3-取代的预催化剂最慢。3-取代的预催化剂的行为可以归因于与相邻大体积苯基相关的电子和空间效应。