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The chemistry of iron covers a wide range of compounds, many of which are important in
the field of catalysis and biochemistry. The chemistry of iron compounds has been
extensively investigated and the relationship between structure and reactivity, ranging
from industrial catalysis to biochemical activity, is of major importance.
Stereoselectivity in complex compounds is very often related to important
stereospecifity of biological system, catalysis and stereochemical effect in technical
processes. Isomers can be broadly classified into two major categories—structural and
stereoisomers. The former can be divided into ionization, hydrate, coordination, linkage
and polymerization subcategories, and the latter can be divided into geometric
(cis-trans, fac-mer), optical and distortion isomerism. It is well-known that isomers are
substances that have the same number and kinds of atoms arranged differently. Because
their structures are different, isomers have different behaviors.
Over 850 heterobinuclear iron compounds have been surveyed (Melník et al., 2006)
with almost 70 isomeric examples noted. In this review we analyze and classify these
isomeric examples. The aim of this presentation is to discuss the factors which could lead
to a better understanding of stereochemical interactions with the coordination sphere of
heterobinuclear iron compounds and examine some cooperative effects between isomeric
types.
The coexistence of two or more species, even within the same crystal, differing only by the
degree of distortion, is typical of the general class of distortion isomerism (Melník, 1982).
There are eight derivatives (Andrianov et al., 1971; Keller and Vahrenkamp, 1978; Gadol
and Davis, 1982; Onaka et al., 1993; Saturnino and Arif, 1993; Mianyong and Vahrenkamp,
1994; Herberich and Moss, 1995; and Behrens et al., 1996) which exist in two isomeric
forms and even one (Sutter et al., 1992) which exists in three isomeric forms and all are
classical examples of distortion isomerism. |
