Chemistry Reference
In-Depth Information
Structural and Bonding Issues in Clusters
and Nano-clusters
D. Michael P. Mingos
Abstract The study of gold cluster compounds origin/ated from Malatesta's syn-
theses of tertiary phosphine derivatives in the 1960s and was greatly extended
between 1970 and 2000. Single crystal X-ray studies defined the major structural
classes and led to the development of a theoretical model which accounted for their
closed shell requirements in terms of their topological features. This model proved
to be sufficiently flexible to be extended to related heteronuclear cluster com-
pounds. Since the turn of the century the range of gold cluster compounds has
been greatly extended by the study of organothiolato-gold cluster compounds and
unligated gold clusters. The structures of the organothiolato-compounds have
revealed that some of the gold atoms combine with the ligands to generate a
novel class of metallo-organothiolato-ligands which protect and stabilise the
inner core of gold atoms. The smaller cluster cone angles of the organothiolato-
based ligands have accessed clusters with higher nuclearities (
100 gold atoms)
some of which have been structurally characterised. These developments originally
suggested that the phosphine and organothiolato-clusters defined quite distinct
classes of gold clusters, but recent structural and theoretical developments have
reconciled many of these differences. This review summarises the structures of the
clusters and suggests a unified theoretical model which accounts for the broad
structural properties of the two classes of compound.
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Keywords Capping principle
Clusters
Condensed clusters
Gold
Jellium
model
Nanoclusters
Oblate
Organothiolato
Phosphine
Polyhedral skeletal
electron pair theory
Prolate
Sphericity
Tensor surface harmonic
Toroidal
