Bonding isolobality principle

The addition of transition metal fragments ML (L = two-electron donor ligand) across formally unsaturated metal-metal or metal-carbon bonds is a well-developed synthetic route to heteronuclear clusters (1,2,11,12,27) and has received theoretical justification from Hoffmann s isolobal principle (46). The addition of a PtL2 fragment across an M=M double bond may be considered as analogous to the reaction of a carbene with an olefin, resulting in a cyclopropane. The use of isolobal analogies in the directed synthesis of heteronuclear clusters has been reviewed (11,12,27). 

Certain L M fragments are often considered carbene-like because there is an analogy between their insertion into X—Y bonds and the insertion of an organic carbene, such as CH2, into a C—H, Si—H, or O—H bond (Eq. 3.17). In Section 13.2, we will see how the isolobal principle allows us to understand the orbital analogy between the two systems. There are several mechanisms... 

Ligands Bonding and spectroscopy 18-electron rule Metal carbonyls Isolobal principle Electron counting schemes Types of organometallic reactions... 

The notion of coordinating molecules containing only inert conventional bonding principles. Clearly a nonclassical form of bonding, e.g., 3c-2e bonding had to join M to Hj or otha- a bonds, as for boron hydrides, carbocations, and (Figure 4.1). Indeed CHj is now considered to be an extremely dynamic complex of CHJ, which bears an isolobal relationships to a... 

Fe(C0)4 is a double connector and is isolobal to CH2. In principle, it can form a molecule with Fe=Fe double bond, which is an analogue of ethylene. It can form a three-membered ring p5 e(CO)4]3, which is an analogue of the (CH2)3 ring. It can form, in principle, many other rings. 

Hoffmann s isolobal analogy is a unifying principle that identifies analogies between organic and inorganic structures in terms of their bonding pattern. Different L M groups are considered isolobal with... 

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