ARENE SOLUTIONS OF GALLIUM CHLORIDE .3. A QUANTUM-CHEMICAL EVALUATIONOF STRUCTURAL MODELS DERIVED FROM X-RAY-SCATTERING AND VIBRATIONAL SPECTROSCOPY

Experimental results from X-ray scattering and vibrational spectroscop y of solutions of GaCl3 and mixed-valence salts Ga(GanCl3n+1) in benze ne and mesitylene are rationalized using applied theoretical calculati ons at Hartree-Fock and 2nd-order Moller-Plesset levels. The interacti on between the aromatic molecules and Ga(III) is strongly suggested to be of (1) pi type. Benzene is indicated to form a mono-bridged Ga2Cl6 (C6H6) complex, whereas the stronger donor mesitylene seems to also fo rm monomeric GaCl3(C9H12) complexes in equilibrium with the mono-bridg ed, Ga2Cl6-mesitylene dimer complex. Ga2Cl7- is shown to have a prefer red bent configuration with a Ga-Cl-Ga angle about 120 degrees. Howeve r, the potential surface is found to be very flat and weak interaction s or packing effects in solid compounds are very likely to influence i ts conformation. (C) 1997 Elsevier Science B.V.