Half-Sandwich Compounds CpML

Half-sandwich Cp complexes with one, two, three, and four additional ligands. 

CHAPTER 3 COVALENT (x-TYPE) LIGANDS BOUND THROUGH METAL-CARBON AND METAL-HYDROGEN BONDS 

Ligands That Are Electronically Similar to the Cyclopentadienyl Ligand 

Several ligands possess frontier orbitals that share the symmetry properties of cyclopentadienyl ligands. For example, the HOMOs on the open C2B3 face of the carboranyl dianion and on the pentagonal C2B3 face of [nzdo-CjB HJ , are similar 

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One of the most important carbon 7i-donors are the cyclopentadienes and their heteroanalogues, for instance 15 and 16. In general, cyclopentadiene itself forms three general types of mononuclear Cp transition metal complexes Cp2M 3 (symmetric molecules with mutually parallel Cp rings examples M = Fe, Cr, Ni), Cp2ML 124 [bent metallocenes, L = H, R, CO, etc. (n=l-3)], and half-sandwich compounds CpML 125 (n — 1 4) [21b], In the bent sandwich complexes... 

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