Electronic structures of coordination

Gas phase U. V. photoelectron spectroscopy as a tool for the investigation of electronic structures of coordination compounds. C. Cauletti and C. Farlani, Comments Inorg. Chem., 1985, 5, 29 (95). 

CNR Laboratory of Theory and Electronic Structure of Coordination Compounds, Rome. 

There are further possible advantages from the use of P.E. spectroscopy in the elucidation of the electronic structure of coordination compounds, and information not otherwise available or only indirectly available may thus come to light. The energy position of ionization bands of nonbonding orbitals, such as 6 s2 in (T1(I),... 

The complexes in Table I have been assigned an end-on geometry on the basis of spectroscopic data, chemical behavior, and, in the case of a macrocyclic rhodium complex, X-ray crystallographic data (53). The 0-0 stretching frequencies and 0-0 bond lengths are useful indicators of the electronic structure of coordinated dioxygen (54-59),... 

CHARACTERISTIC FEATURES OF THE ELECTRONIC STRUCTURE OF COORDINATION COMPOUNDS... 

To give more breadth to our discussion of the connections between molecules and solids we now consider examples of systems in which one can see transition-metal complexes. They are of pedagogical interest because their simple electronic structures can be used to good effect in elementary treatments of the electronic structure of coordination compounds. 

Until now we considered the topology of various organic molecules. In inorganic chemistry the topological methods are not so popular. Therefore, in this chapter we shall confine ourselves to only two topics, the topological theory of borane structure and the discussion of the interrelationship between topology, symmetry, and electronic structure of coordination compounds. 

Different names have been used for the theoretical approaches to the electronic structure of coordination complexes, depending on the preferences of the authors. The labels we will use are described here, in order of their historical development ... 

Various theoretical approaches to the electronic structure of coordination complexes have been developed. We will discuss three of these bonding models. 

Scientists have long recognized that many of the magnetic properties and colors of transition-metal complexes are related to the presence of d electrons in the metal cation. In this section we consider a model for bonding in transition-metal complexes, crystal-field theory, that accounts for many of the observed properties of these substances. Because the predictions of crystal-field theory are essentially the same as those obtained with more advanced molecular-orbital theories, crystal-field theory is an excellent place to start in considering the electronic structure of coordination compounds. 

Molecular and electronic structures of penta- and hexa-coordinate silicon compounds. S. N. Tan-dura, M. G. Voronkov and N. V. Alekseev, Top. Curr. Chem., 1986,131, 99 (1008). 

Axe, J. D. "Electronic Structure of Octahedrally Coordinated Protactinium(IV) in Cs2ZrCl6", UCRL-9293,... 

The striking feature of many coordination compounds is that they are colored or paramagnetic or both. How do these properties arise To find out, we need to understand the electronic structures of complexes, the details of the bonding, and the distribution of their electrons. 

In a crystal-field picture, the electronic structure of iron in the five-coordinate compounds is usually best represented by a (d yf idyz, 4cz) ( zO configuration [66, 70], as convincingly borne out by spin-unrestricted DFT calculations on the Jager compound 20 [68]. The intermediate spin configuration with an empty d 2 yi orbital in the CF model, however, has a vanishing valence contribution to the... 

Four-coordinate, planar iron(II)-dithiolate complexes also exhibit intermediate spin. The first example described was the tetraphenylarsonium salt of the square-planar bis(benzene-l,2-dithiolate)iron(II) dianion, (AsPh4)2[Fe(II)bdt2], which showed 5 = 0.44 mm s and AEq = 1.16 mm s at 4.2 K [157]. The electronic structure of a different salt was explored in depth by DFT calculations, magnetic susceptibility, MCD measurements, far-infra red spectroscopy and applied-field Mossbauer spectroscopy [158]. 

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