Reference : Theoretical investigation of the molecular structure of aluminium triisopropoxide and it...
Scientific journals : Article
Engineering, computing & technology : Materials science & engineering
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/15441
Theoretical investigation of the molecular structure of aluminium triisopropoxide and its complexes in ring-opening polymerization
English
Parenté, Vincent [University of Mons-Hainaut (UMH) > > Service de Chimie des Matériaux Nouveaux, Centre de Recherche en Electronique et Photonique Moléculaires > >]
Brédas, Jean-Luc [University of Mons-Hainaut (UMH) > > Service de Chimie des Matériaux Nouveaux, Centre de Recherche en Electronique et Photonique Moléculaires > >]
Dubois, Philippe [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
Ropson, Nathalie [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
Jérôme, Robert mailto [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
May-1996
Macromolecular Theory and Simulations
Wiley VCH Verlag
5
3
525-546
Yes (verified by ORBi)
International
1022-1344
[en] ring-opening polymerization (ROP) ; lactone
[en] We present a theoretical study on aluminium triisopropoxide (Al(O1Pr)3) using both empirical (Molecular Mechanics, MM, with Dreiding II force field) and quantum-chemical (Austin Model 1, AMI, semiempirical Hartree-Fock) techniques. We determine the most stable geometries for both the tetramer and tiimer of aluminium triisopropoxide as well as the thermodynamic characteristics of the equilibrium existing between these two aggregated structures. The theoretical results are compared to experimental data from X-ray diffraction and 27Al NMR measurements. For the tetramer, it appears that the optimal equilibrium geometries are in good agreement with the experimental X-ray diffraction geometry; another geometry is also obtained with both theoretical approaches, which is slightly less stable but of higher symmetry. On the basis of the most stable configurations for the tetramer and trimer aggregates, the variation of free enthalpy (AG) between the two aggregated structures has been estimated. The evolution of the theoretical AG values indicates a displacement of equilibrium towards the trimer species with temperature, in good agreement with experimental 1H and 27Al NMR data. Moreover, the AMI heats of formation show a gain of 33.9 kcal/mol due to the aggregation of four Al(O1Pr)3 instead of three, and thus a better stability of the tetramer. The molecular geometries being well described by the theoretical methods used in this study, we also present a model for the ring-opening polymerization complexes of ε-caprolactone and lactides.
Center for Education and Research on Macromolecules (CERM)
Politique Scientifique Fédérale (Belgique) = Belgian Federal Science Policy ; Fonds pour la formation à la Recherche dans l'Industrie et dans l'Agriculture (Communauté française de Belgique) - FRIA ; Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS ; IBM
Researchers
http://hdl.handle.net/2268/15441
10.1002/mats.1996.040050309
http://www3.interscience.wiley.com/cgi-bin/fulltext/104081345/PDFSTART

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