Zinc oxide clusters encapsulated by organozinc phosphazenate assemblies

Phosphazenes (iBuNH)6P3N3 and (BzNH)6P3N3 were combined with 1.5 equivalents of water and 7.5 equivalents of diethylzinc resulting in the formation of zinc oxide phosphazenate complexes Zn3O2[(iBuN)6P3N3(EtZn)5]2 (6) and Zn2O2[(BzN)6P3N3(EtZn)6]2 (7), respectively. X-ray structure analysis showed that in both complexes the organozinc phosphazenate moieties encapsulate the zinc oxide clusters, Zn3O2 (in 6) and Zn2O2 (in 7), which were generated in situ by hydrolysis of Et2Zn. The geometry and nuclearity of the encapsulated zinc oxide clusters is largely controlled by the steric bulk of the host phosphazenate arrangement, which offers well-defined arrays of Lewis acidic Zn and Lewis basic N sites for coordinating both zinc and oxide ions.