Dimetallic Dioxygen Activation Leading to a Doubly Oxygen‐Bridged Dirhodium Complex

Abstract

Ready cleavage of dioxygen and its selective insertion into Rh–alkene bonds occurs in the presence of [{Rh(PhN3Ph)(C8H12)}n] (n=1 and 2). The structure of the resulting dirhodadioxetane complex (see picture) and kinetic measurements support a dimetallic mechanism for this process that occurs with 100 % atom economy.

Rhodium Complexes Promoting C−O Bond Formation in Reactions with Oxygen: The Role of Superoxo Species

“…Isomerization of 4 into 6 can be easily understood in terms of a shift of the allylic proton H 4 toward the closest oxygen with formation of the allyl moiety and the cleavage of the Rh−O bond. A similar isomerization was observed for complex [{Rh(OC 8 H 12 )(Ph 2 N 3 )} 2 ] ( 2 ), so that in both cases, the 2‐rhodaoxetane complexes 2 and 4 were found to be the kinetic isomers of the oxygenation reaction, whereas the 1‐hydroxy‐2‐rhoda‐5,6,7‐allylcyclooctenyl complexes are the thermodynamic ones.…”

“…Studies were initiated by optimizing with the MPWB1K functional (see Supporting Information) the ground‐state structure of the mononuclear complex [Rh(cod)(Ph 2 N 3 )] ( 1 ) and the 2‐rhodaoxetane compound [{Rh(OC 8 H 12 )(Ph 2 N 3 )} 2 ] ( 2 ). Metric parameters of the optimized structure for 2 were found to be in a very good agreement to those found in the molecular structure of the complex (see Supporting Information). For the mononuclear compound 1 , no molecular structure is available…”

“…Although 2‐metallaoxetanes have been known for a long time, those coming from reactions with dioxygen are scarce, with only two isolated examples in rhodium and iridium chemistry, namely the mononuclear complex [Ir(OC 8 H 12 )(P 3 O 9 )] 2− and the dinuclear [{Rh(OC 8 H 12 )(Ph 2 N 3 )} 2 ] . Noticeably, O 2 uptake measurements for both reactions proved that these are 100 % atom‐economy processes.…”

“…Some of us reported the oxygenation of cod in the mononuclear complex [Rh(cod)(Ph 2 N 3 )] ( 1 ) to the unique dinuclear 2‐rhodaoxetane compound [{Rh(OC 8 H 12 )(Ph 2 N 3 )} 2 ] ( 2 , Scheme ), which has remained since then as the single example in rhodium chemistry …”

Guanidinato and amidinato complexes of iridium(I)

“…9 There are two examples that form metallaoxetane species in solution by an atomeconomic (both atoms of O 2 are incorporated) reaction with O 2 . 26,27…”