New results are presented concerning the topotactic self-assembly, n-type
doping and band-gap engineering of an intrazeolite tungsten(VI) oxide supralattice
n(W03)-Na56Y, where 0 < η < 32, built-up of single size and shape (W03)2
dimers. In particular it has been found that the oxygen content of these dimers
can be quantitatively adjusted by means of a thermal vacuum induced reversible
reductive-elimination oxidative-addition of dioxygen. This provides access to new
n(W03.x)-Na56Y materials (0 < χ ^ 1.0) in which the oxygen content, structural
properties and electronic architecture of the dimers are changed. In this way one
can precisely control the oxidation state, degree of η-doping and band-filling of a
tungsten(VI) oxide supralattice through an approach which can be considered akin
to, but distinct in detail to, that found in the Magneli crystallographic shear phases
of non-stoichiometric bulk W03.x . Another discovery concerns the ability to alter
local electrostatic fields experienced by the tungsten(VI) oxide moieties housed in
the 13Ä supercages of 16(W03)-M36Y, by varying the ionic potential of the
constituent supercage M + cations across the alkali metal series. This method
provides the first opportunity to fine-tune the band-gap of a tungsten(VI) oxide
supralattice. Α miniband electronic description is advanced as a qualitative first
attempt to understand the origin of the above effects. The implications of these
discoveries are that cluster size, composition and intrinsic electrostatic field effects
can be used to "chemically manipulate" (engineer) the doping and band
architecture of intrazeolite supralattices of possible interest in quantum electronics
and nonlinear optics