The equilibrium between aluminum alkoxides and 1-(diphenylphosphinoyl)-2-(diphenylphosphino)ethane

• Published in: Inorganica Chimica Acta 2002-07, Vol.336, p.115-119
• Main Authors: Amenta, Donna S., Ayres, Benjamin R., Jurica, Jon, Gilje, John W.
• Format: Article
• Language: English
• Subjects: Aluminum-alkoxide phosphine-oxide complex; Equilibrium thermodynamics
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(02)00843-5

The reaction of Ph 2P(O)CH 2CH 2PPh 2 with several aluminum alkoxides was studied. No reaction was detected with [Al(OEt) 3] n or [Al(OPr i) 3] 4. In contrast, [Al(OBu t) 3] 2 or [Al(OBu s) 3] n in methylene chloride are in equilibrium with (RO) 3AlOPPh 2CH 2CH 2PPh 2. In the case of [Al(OBu s) 3] n equilibrium constants have been obtained and are consistent with: 1/2[Al(OBu s) 3] 2+Ph 2P(O)CH 2CH 2PPh 2⇌(Bu sO) 3AlOPPh 2CH 2CH 2PPh 2. Plots of − RT ln K eq versus 1/ T between −20 and 35 °C yield Δ H=10.5±0.5 kJ mol −1 and Δ S=38±2 J K −1 mol −1. In methylene chloride, Ph 2P(O)CH 2CH 2PPh 2 with [Al(OBu t) 3] 2 or [Al(OBu s) 3] 2 are in equilibrium with (RO) 3AlOPPh 2CH 2CH 2PPh 2. In the case of [Al(OBu s) 3] 2 equilibrium constants have been obtained for: 1/2[Al(OBu s) 3] 2+Ph 2P(O)CH 2CH 2PPh 2⇌(Bu sO) 3AlOPPh 2CH 2CH 2PPh 2. Plots of − RT ln K eq versus 1/ T between −20 and 35 °C yield Δ H=10.5±0.5 kJ mol −1 and Δ S=38±2 J K −1 mol −1.