Main-group metallocene

Reviews of quantum chemical calculations on main group metallocenes that include group 2 species are available.388 389... 

Metal-Carbon Distances in Linear Main-Group Metallocenes... 

Fig. II. Variations in the spread of M-C distances (AM C) in main-group metallocenes with cyclopentadienyl rings of different steric bulk.

Table IV contains calculated 8 values for bent main-group metallocenes there is not a strong correlation with the substituents on the ring. Thus, for the case of stannocenes, both the Cp and the Ph5Cp ring in [Sn (C5Ph5)Cp]120 have 8 = 82.5°, and the highly substituted [Sn(C5(/-Pr)4H)2]79 has 8 = 83.6°, whereas one of the two forms of [SnCp2] has 8 = 85.2°.17 Clearly, packing effects can influence the angle, as the other [SnCp2] molecule has 8 = 82.5°.

Fig. 7. Frontier orbital stabilization in the bending of a main group metallocene.

Since main group metallocenes show weak proclivity toward directional bonding between the Cp ring and the central atom due to the lack of available d orbitals for n-type interaction, different hapticities (referred to as ring slippage) from rj to rj (Fig. 4) rather than prototype i) can often be observed. If a metallocene has two or more equidistant C(Cp)-E bonds, it can be classified as a jr complex with hapticities of while a metallocene with an T -Cp has a a type of interaction between C(Cp)-E (9). These different hapticities are due to... 

Figure 5 MO diagram for the half-sandwich main group metallocene symmetry).

RESULTS AND DISCUSSIONS OF PREVIOUS COMPUTATIONAL STUDIES OF MAIN GROUP METALLOCENES... 

This section introduces the available computational methods and explains how to treat main group metallocenes effectively using computational methods. 

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