Hydrocarbyl ligands

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... 

Alkyne-substituted transition metal clusters have been reviewed,122,123 and other reviews of interest have discussed cyclopentadienyl metal clusters of group 9 transition metals124 and hydrocarbyl ligand derivatives of group 6 through group 9 heterometallic clusters.125... 

Hydrocarbyl ligand bonded through carbon and containing hydrogen... 

As the cluster nuclearity increases, the structures and electron counting of saturated clusters conform to the polyhedral skeletal electron pair (SEP) theory. For organometallic clusters the carbon fragments of the hydrocarbyl ligands are frequently part of the cluster skeleton. Thus, Fc3(PhCCPh)(CO)9 (1) would be considered to be unsaturated according to the 18-electron rale, as the alkyne ligand is a four-electron donor to a Fc3(CO)9 cluster, which requires... 

While numerous clusters containing exotic hydrocarbyl ligands have been prepared and unique chemical reactivity demonstrated, the most weU-estabhshed chemistry concerns hydrocarbyl fiagments bound to the metal framework through one, two, or three carbon atoms. A sampling of the chemistry of these fragments will illustrate many of the unique aspects of organometallic cluster chemistry. 

In light of the utility of spectroscopic comparisons between surface adsorbed species and cluster models, it is surprising that so few of the more unique cluster-bound hydrocarbyl ligands have been spectroscopically characterized. Given the exceptional stabilities of structures such as /xs-jj -RCCR CR" in cluster systems, it is to be expected that such fragments are also to be found on metal surfaces. 

Lanthanide Complexes with cr-Bonded Hydrocarbyl Ligands 1... 

LANTHANIDE COMPLEXES WITH n-BONDED HYDROCARBYL LIGANDS... 

CH2=C=CPh)] (39b). The latter two complexes display very similar structural characteristics. Both complexes contain hydrocarbyl ligands in which i/(CH2-C) exceeds /(C-CR). For instance, in the molybdenum complex these distances are 1.380(2) A and 1.263(4) A, whereas those reported by Wojcicki are 1.39(2) and 1.23(1) A. Such data were interpreted in terms of a large contribution from the 17 -propargyl resonance structure [105(1) and 39(1)), respectively]. However, values of 7ch indi-... 

The allenyl cluster [Ru3H(CO)9(jU,-i7, yj, i7--MeCCC(H)NMe2)] (101). with a hydrocarbyl ligand which closely resembles a zwitterionic alkyne. 

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