Hydrocarbyl ligands significance

Despite this significant early work, the chemistry of r 2-hydrocarbyl complexes has not been appreciably further developed, and relatively few examples of "simple" r 2-hydrocarbyl ligands are recorded. Indeed, TpPtMe(ri -C2H4) (100)60 was the sole complex of C2H4 known before 2000, and only six more have been reported since. These were obtained by low-temperature protonation of the hydride complexes Tp Pt(R) H3 (R = Me, n = 2 151,65 n 1 152 66 R = Ph, n = 2 153,67 see also Section III.E) with... 

The organisation of this Report is similar to that of Volume 13. Cyclopentadienyl and arene complexes that contain metal-metal bonds, carbene, carbyne, or hydrocarbyl ligands, and reactions that involve replacement or elaboration of other ligands present, generally are not included (see Chapters 9-13). Only those metalla-borane and -carbaborane complexes that also incorporate a Cp or arene ligand are described, and crystal-structure determinations are included only where results of particular significance or solutions to structural problems are provided. 

Protonolysis of the typically polar bond between a group 6 metal and a hydrocarbyl ligand is usually considered to be an unwanted decomposition reaction. When metal—heteroatom bonds are desired, however, selective alkane-elimination reactions can sometimes offer significant advantages, such as ready availability and stability of the protonated source of the desired ligand (such as carboxylic acids, alcohols, or amines) and the absence of inorganic salts as byproducts (the resulting alkane is normally easily removed... 

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