Chapter 5
The Symmetry Properties Describe
the Electronic Structure of Inorganic
and Coordination Compounds
The previous four chapters reported the fundamentals of the symmetry properties
with the use of the group theory, aiming to describe the electronic structure of
transition metal complexes and to make prevision of it. These principles are
important not only as a base knowledge of the matter structure, but as a starting
point to predict reactivity. Reactivity is in turn essential to explain the functionality
of the chemical units.
The symmetry-based methods will be used in the following to show which way
the case studies can be resolved. Symmetry, electronic structure, and magnetic
properties will contribute together. The examples have been taken from published
results.
The description will show the case, then it will report the discussion of the case,
and finally it will give a functional chemical message.
5.1 The Case of [Fe 3 Pt 3 (CO) 15 ]
n− n = 2, 1,
and of [Fe 3 Pt 3 (CO) 15 ]
2-n
These organometallic compounds belong to the carbonyl cluster family and are
constituted by Fe and Pt centers linked one to another and to terminal CO groups, as
in Fig. 5.1 [3,4]. Several electronic and structural problems are connected to carbonyl clusters and more in general to metal clusters, beginning from the model of
chemical bond between the metal centers and going to hypotheses of electronic
properties connected with their reactivity. This should in principle allow to
understand how the metal centers undergo interaction and increase the cluster
nuclearity (number of interacting metal centers). The crystal and ligand field theories are not suitable to rationalize the bond interaction as any single metal center is
not coordinated with only CO ligand molecules. Basing on the symmetry properties
of the molecules in Fig. 5.1, belonging to D 3h group, a description can be
© Springer Nature Switzerland AG 2021
F. Morazzoni, Symmetry in Inorganic and Coordination Compounds, Lecture Notes
in Chemistry 106, https://doi.org/10.1007/978-3-030-62996-0_5
85
The Symmetry Properties Describe
the Electronic Structure of Inorganic
and Coordination Compounds
The previous four chapters reported the fundamentals of the symmetry properties
with the use of the group theory, aiming to describe the electronic structure of
transition metal complexes and to make prevision of it. These principles are
important not only as a base knowledge of the matter structure, but as a starting
point to predict reactivity. Reactivity is in turn essential to explain the functionality
of the chemical units.
The symmetry-based methods will be used in the following to show which way
the case studies can be resolved. Symmetry, electronic structure, and magnetic
properties will contribute together. The examples have been taken from published
results.
The description will show the case, then it will report the discussion of the case,
and finally it will give a functional chemical message.
5.1 The Case of [Fe 3 Pt 3 (CO) 15 ]
n− n = 2, 1,
and of [Fe 3 Pt 3 (CO) 15 ]
2-n
These organometallic compounds belong to the carbonyl cluster family and are
constituted by Fe and Pt centers linked one to another and to terminal CO groups, as
in Fig. 5.1 [3,4]. Several electronic and structural problems are connected to carbonyl clusters and more in general to metal clusters, beginning from the model of
chemical bond between the metal centers and going to hypotheses of electronic
properties connected with their reactivity. This should in principle allow to
understand how the metal centers undergo interaction and increase the cluster
nuclearity (number of interacting metal centers). The crystal and ligand field theories are not suitable to rationalize the bond interaction as any single metal center is
not coordinated with only CO ligand molecules. Basing on the symmetry properties
of the molecules in Fig. 5.1, belonging to D 3h group, a description can be
© Springer Nature Switzerland AG 2021
F. Morazzoni, Symmetry in Inorganic and Coordination Compounds, Lecture Notes
in Chemistry 106, https://doi.org/10.1007/978-3-030-62996-0_5
85