PNNL

Abstract

Ruthenium pincer complexes have a rich several decade long history of coordination chemistry and utilization in catalysis. In this work, we report our discoveries that expand our knowledge of Ru pincer coordination chemistry with previously unreported coordination moieties. We found that mono tuck-in ?4-ArPNHPRuLCl complexes react with NaN(SiMe3)2 producing double tuck-in ?5-ArPNHPRuL complexes. The double tuck-in complexes form through ?4-ArPNPRuL, amide intermediates that rapidly add a second ortho methyl C-H bond across the Ru-N bond. To the best of our knowledge, this unique bonding moiety has not been previously reported for pincer complexes upon double dehydrohalogenation. Interestingly, when ?4-MesPNHPRuCl is dehydrohalogenated the resulting double tuck-in complex binds N2 forming the nitrogen complex ?5-MesPNHPRuN2. The double tuck-in, meridional ?5-ArPNHPRuL complexes isomerize to the facial ?5- ArPNHPRuL isomers upon heating, an uncommon reaction for pincer complexes. Also, these complexes react with CO and CO2 to form trapped amide ?4-ArPNHPRu(CO)L or carbamate ?5-ArPN(CO2)PRuL complexes, respectively, supporting the suggestion that the ?4-ArPNPRuL amide intermediates are accessible and reactive.