At present, there is no general description of the interactions between nitrogen heterocycles and the active catalyst sites in heterogeneous hydrodenitrogenation (HDN) catalysts that promote hydrogenation and then hydrogenolysis of the C-N bond. We have attempted to model such interactions through studies of the reactions of osmium and ruthenium clusters with common HDN model substrates, including quinoline, pyridine, tetrahydroquinoline (THQ), and piperidine. Os3(CO)12 and Ru3(CO)12 with quinoline Or pyridine lead to complexes of the general formula 3(µ-:µ-Y) (CO) 10 (M = Ru, Os; Y = C9H6N, C9H8N, C5H8N) or 3(µ-:µ-)2(00)8 (M = Ru, Os; Y = C5H4N, C9H6N). The reactions of Os3(CO)12 with aliphatic heterocyclic amines leads to complexes having stoichiometries of 083(µ-:µ-Y)(CO)10 (Y = C5H8N, C9H8N, C9H6N), 83(µ-)2(µ-)(µ-0( 0)8 (Y = C9H8N, Y' = C9HeN), or Os3(M-H:M-Y)2(CO)8 (Y = C9H6N), and when the heterocyclic amine is 1,2,3,4-tetrabydroquinoline (THQ), a small amount of free quinoline is also produced. As a general rule, both aliphatic and aromatic nitrogen heterocycles undergo -metalation during reactions with both homogeneous and heterogeneous metal complexes or particles. In the case of osmium and ruthenium, metalation results in the formation of metalloazocyclobutenes even when the starting heterocycle is saturated. Thus, activation / dehydrogenation of the N-H and -C-H bonds of secondary amines occurs readily in the systems described here. Reaction pathways for the formation of the various products and their relationships to hydrogenation and dehydrogenation catalysis are proposed.
gel, eluting the isomerically pure product with 20% acetonehexane: yield 1.833 g (61%); IR (neat) 1670,1645 (C=0) cm™1.The compound should be handled as 12a.
Isomerization of Substituted Allylbenzenes (15a-c).Isomerization on 15a-c was effected in boiling toluene by using 2 as a catalyst and a substrate to catalyst ratio of 200.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.