Aluminum trichloride ammonia complex

So far, our discussion of reactions has been restricted to organic molecules. However, all the main ideas are applicable to inorganic systems as well. Thus, for example, the formation of inorganic donor-acceptor complexes may be conveniently described by the HOMO-LUMO concept. A case in point is the formation of the aluminum trichloride-ammonia complex (cf. Figure 3-15). This complex can be considered to result from interaction between the LUMO of the acceptor (A1C13) and the HOMO of the donor (NH3). 

Figure 3-22. The uncomplexed ammonia and aluminum trichloride molecules and the triangular antiprismatic shape of the HjN-AlCl, donor-acceptor complex.

Zinc chloride has been used in place of aluminum chloride for the reaction of polyhydric phenol ethers with phosphorus trichloride, suitable working up again giving the tertiary phosphines. The resulting ZnCl2 complexes are successfully decomposed by aqueous ammonia.157... 

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