Picture of wind turbine against blue sky

Open Access research with a real impact...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs.

The Energy Systems Research Unit (ESRU) within Strathclyde's Department of Mechanical and Aerospace Engineering is producing Open Access research that can help society deploy and optimise renewable energy systems, such as wind turbine technology.

Explore wind turbine research in Strathprints

Explore all of Strathclyde's Open Access research content

Contacted ion-pair lithium alkylamidoaluminates: intramolecular alumination (al-h exchange) traps for tmeda and pmdeta

Conway, Ben and Garcia-Alvarez, Joaquin and Hevia, Eva and Kennedy, Alan R. and Mulvey, Robert E. and Robertson, Stuart D. (2009) Contacted ion-pair lithium alkylamidoaluminates: intramolecular alumination (al-h exchange) traps for tmeda and pmdeta. Organometallics, 28 (22). pp. 6462-6468. ISSN 0276-7333

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

Exploring the reactivity of mixed-metal synergic bases, it is found that the lithium TMP aluminate iBu3Al(TMP)Li functions as a dual TMP/alkyl base, exhibiting 2-fold AMMAl (alkali-metal-mediated alumination) toward TMEDA to yield the heterobimetallic bis-(deprotonated TMEDA) derivative [Li{Me2NCH2CH2N(Me)CH2}2Al(iBu)2] (2). In contrast, the amide enriched aluminate iBu2Al(TMP)2Li acts as only a single-fold amido base toward TMEDA or PMDETA to afford the amine-deprotonated derivatives [Li{Me2NCH2CH2N(Me)CH2}(TMP)Al(iBu)2] (4) and [Li{Me2NCH2CH2N(Me)CH2CH2N(Me)CH2}(TMP)Al(iBu)2] (5), respectively. On their own, the aluminum compounds iBu3Al or iBu2Al(TMP) are not sufficiently strong bases to metalate TMEDA or PMDETA, so in 2, 4, and 5, the α-deprotonations of TMEDA and PMDETA are synergic in origin, as the intramolecular communication between Li and Al appears to activate the TMP and iBu bases. This special behavior can be attributed to intramolecular proximity effects between the active base component (TMP or iBu) and the ligating TMEDA or PMDETA molecule. X-ray crystallography studies reveal 2 is a contacted ion-pair ate containing two α-aluminated TMEDA ligands, which chelate the lithium cation which is linked to the distorted tetrahedral Al center by two N bridges from the metalated junction of the TMEDA molecules. In contrast, 4 and 5 have a mixed NCH2-TMP bridging ligand set, completed by two terminal iBu ligands on Al and a chelating metalated TMEDA or PMDETA ligand attached to Li, respectively. In addition, the 1H, 7Li, and 13C{1H} spectra of 2 (recorded in C6D6 solutions), 4, and 5 (recorded in cyclohexane solutions-d12) are disclosed.