title: CO2 and formate complexes of phosphine/borane frustrated Lewis pairs.
abstract: The reaction of a solution of B(C6F4H)3 and either iPr3P or tBu3P with CO2 afforded the species R3P(CO2)B(C6F4H)3 (R=iPr (1), tBu (2)). In a similar fashion the boranes, RB(C6F5)2 (R=hexyl, cyclohexyl (Cy), norbornyl), ClB(C6F5)2, or PhB(C6F5)2 were combined with tBu3P and CO2 to give the species tBu3P(CO2)BR(C6F5)2 (R=hexyl (3), Cy (4), norbornyl (5), Cl (6), Ph (7)). Similarly, the compounds [tBu3PH][RBH(C6F5)2] (R= hexyl (8), Cy (9), norbornyl (10)) were prepared by reaction of the precursor frustrated Lewis pair (FLP) with H2. Subsequent reactions of 9 and 10 with CO2 afforded the species [((C6F5)2BR)2(μ-HCO2)][tBu3PH] (R= Cy (11), norbornyl (12)). In related chemistry, combinations of the boranes RBG(C6F5)2 (R=hexyl, Cy, norbornyl) with tBu3P treated with an equivalent of formic acid gave [(C6F5)2BR(HCO2)][tBu3PH] (R=hexyl (13), Cy (14), norbornyl (15)). Subsequent addition of an additional equivalent of borane provides a second synthetic route to 11 and 12. Crystallographic studies of compounds 2-6 and 8-14 are reported and discussed. Further understanding of the FLP complexation and activation of CO2 is provided by computational studies.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, ON, Canada.
authors.forename: Ilona
authors.initials: I
authors.lastname: Peuser
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Neu
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Zhao
authors.forename: Matthias
authors.initials: M
authors.lastname: Ulrich
authors.forename: Birgitta
authors.initials: B
authors.lastname: Schirmer
authors.forename: Jens A
authors.initials: JA
authors.lastname: Tannert
authors.forename: Gerald
authors.initials: G
authors.lastname: Kehr
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Stefan
authors.initials: S
authors.lastname: Grimme
authors.forename: Gerhard
authors.initials: G
authors.lastname: Erker
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Stephan