Thermodynamics of the decomposition processes of donor-acceptor complexes MX3·en·MX3 and MX3·en

Cong Trinh, Alexey Y. Timoshkin, Gernot Frenking

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6 Citations (Scopus)

Abstract

The structural and thermodynamic properties of the donor-acceptor (DA) complexes of Group 13 metal halides (MX3) with ethylenediamine and their decomposition products have been studied theoretically at the B3LYP/LANL2DZ(d,p) level of theory. Gasphase dissociation into various components and HX elimination reactions are considered. Both processes are endothermic but favored by entropy. Complexes of 2:1 composition are predicted to be stable in the gas phase up to 640-1000 K. It is found that complexation with the second acceptor molecule lowers the HX elimination enthalpy; in turn, HX elimination increases DA bonding with a second MX3 molecule. Exceptionally high values of the dissociation enthalpies (310-390 kJ mol -1) and HX elimination reactions (360-420 kJ mol-1) of the amido compounds MX2NHC2H4NH2 and MX2NHC2H4NHMX2 make them important intermediates in the decomposition processes. Dissociation reactions of the complexes are more favorable than HX elimination reactions; however, the subsequent oligomerization and cyclization processes of coordinationally unsaturated amido and imido compounds may facilitate HX elimination. Since HI elimination reactions are predicted to be the least endothermic, and aluminum-containing compounds have the strongest M-N dissociation enthalpies, it is expected that compounds based on aluminum iodide are promising objects for experimental studies.

Original languageEnglish
Pages (from-to)425-432
Number of pages8
JournalChemPhysChem
Volume8
Issue number3
DOIs
Publication statusPublished - 19 Feb 2007

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Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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