Charge Distribution and Donor Properties in Complexes L·Me^IIIX₃ (L  ArCOAr, ArCOCl, ArOH; Me^III  Al, Ga; X  Cl, Br) and (ArOAlBr₂)_x. An NQR (³⁵Cl, ⁸¹Br, ⁶⁹Ga) and IR (ṽ(C  O), ṽ(CCl)) Investigation

Abstract

Molecular compounds of the type L · MeX3 (L  benzophenones, benzoylchlorides, 4‐chlorophenol; MeX3  AlBr3, AlCl3, GaCl3) were studied by NQR and IR spectroscopy. Also, in two compounds of the type chlorophenoxy aluminumdibromide the halogen NQR was investigated. On the basis of the 35Cl and 81Br NQR experiments, benzoylchlorides appear to be weaker donors than benzophenones are. Yet, the shift of the carbonyl stretching frequency due to the formation of the complexes is less for benzophenones. In adducts of benzoylchlorides with AlCl3 the shift of the 35Cl NQR frequency (assigned to Cl linked to the carbonyl C atom), Δv(35Cl), and the shift of the CCl stretching frequency, Δṽ(CCl), were measured. A positive correlation of Δv(35Cl) with Δṽ(CCl) was found. On the basis of the 69Ga and 35Cl NQR frequencies measured for some molecular compounds L · GaCl3 the charge transfer was estimated with the aid of the Townes and Dailey Theory. A comparison with results obtained analogously for inorganic complexes incorporating GaCl3 is given. From the NQR experiments conclusions concerning the structure of the compounds investigated were drawn.