Borane‐Mediated Carbon Dioxide Reduction at Ruthenium: Formation of C₁ and C₂ Compounds

Abstract

Eins und zwei: Die C2‐Verbindung pinBOCH2OCHO (siehe Schema, HBpin=Pinakolboran) und mehrere C1‐Verbindungen werden bei der boranvermittelten CO2‐Reduktion mit der Katalysatorvorstufe [RuH2(H2)2(PCy3)2] unter milden Bedingungen erhalten. Mechanistische Studien decken die Rolle verschiedener neuer Carbonylruthenium‐Komplexe auf, die mit Mehrkern‐NMR‐Spektroskopie, IR‐Spektroskopie und Röntgenstrukturanalyse charakterisiert wurden.

Frustrated Lewis Pair Inspired Carbon Dioxide Reduction by a Ruthenium Tris(aminophosphine) Complex

“…After 4 h, the presence of the monohydroboration product of CO 2 (from intermediate A ) was evidenced by the appearance of a signal at 158 ppm. This signal is similar to that recently reported by Sabo‐Etienne and co‐workers 13. Structure A appears initially but is fully consumed after 24 h, suggesting its intermediate nature.…”

“…Analogous products are obtained with catecholborane and 9‐BBN. Although these products are similar to those observed by the groups of Guan,12 and Sabo‐Etienne,13 the RuNP ring of 3 is reminiscent of FLP systems. Moreover, the binding of CO 2 in 4 and of aldehyde in 5 exploits the cooperative action of the pendant Lewis basic phosphine and Lewis acidic Ru center.…”

“…For example, the groups of Sadighi17 and Guan12 have achieved catalytic reduction of CO 2 using borane to CO and methoxide, respectively. Most recently, Sabo‐Etienne and co‐workers13 have illuminated the mechanism of reduction of CO 2 by [RuH 2 (H 2 ) 2 (PCy 3 ) 2 ] and pinacolborane (HBpin).…”

Trapping Formaldehyde in the Homogeneous Catalytic Reduction of Carbon Dioxide

“…In the CO 2 reduction reported earlier, HBpin was readily transformed (<30 min.) into compounds 7 – 11 20. A slow retransformation of 9 – 11 into 7 – 8 was achieved (22 days).…”

“…We recently reported the catalytic reduction of CO 2 by [RuH 2 (H 2 ) 2 (PCy 3 ) 2 ] ( 1 ; Cy=cyclohexyl) and pinacolborane (HBpin) reductant 20. Complexes 2 – 6 (Scheme ) are crucial to the catalytic cycle affording compounds 7 – 11 (Scheme ).…”