Si-Donor Ligands

Si-Donor Ligands. [o-(Diphenylphosphino)benzyl]dimethylsilane reacts with [Re2(CO)io] in benzene at 150 °C to form the mono-substituted complex (102), which does not involve co-ordination of phosphorus. 

During alkylation of Ag[Re(CN)6] the addition compound [Re(CNMe)6],-8AgI is formed, which decomposes in the presence of alkali with evolution of MeNC, but with HNO3 and AgNOa gives [Re(CNMe)6](N03)2. °  

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Si-, Ge-, and Sn-donor Ligands. The synthesis of [H SiCriCOijfTi-Cp)] has been reported in more detail and the chemical properties of the compound have been described. The Si—Cr bond is cleaved at room temperature by HjO and HCl and at slightly elevated temperatures by Mc2NH. At room temperature the primary reaction of McjNH and McjN is to form an adduct with the compound. 

A structural investigation of [Ta(=CH Bu)(CH2 Bu)3] grafted on siUca partially dehydroxylated at 700 °C using EXAFS [18] has revealed a short-range interaction of 2.64 between the O-atom from a siloxane bridge and tantalum. This O-atom acts as a two-electron donor ligand to stabiUze the formally ten-electron surface complex [(=SiO)Ta(=CH Bu)(CH2 Bu)2j, yielding the more stabiUzed twelve-electron species [(=Si0)Ta(=CH Bu)(CH2 Bu)2(=Si-0-Si j (Scheme 11.9). 

Scheme 12.3 Synthesis of rare-earth metal (Ln) surface complexes, that is, heterogenized Ln single-sites, on silica Do = donor ligands, L = monoanionic ligands and M = Al, Mg, Zr or Si M = Si refers to tethered surface species.

Na Mg Ca Metal clusters Metal clusters with jr-donor ligands] with -acceptor ligands Al Si P s Cl Ar... 

N Si coordination (76, 7776 78a77 ) and most recently also with oxygen (78b,78 7 979), sulfur (78c),78 and phosphorus (78d)78 donor-ligands. The present section describes the chemistry of donor-stabilized silyl cations with hydrazido chelates. 

Inspection of Table 8-1 clearly shows that this trend cannot be explained exclusively in terms of ionization enthalpies, since these are essentially the same for all the elements Si—Pb. The inert pair concept probably holds only for the lead ion Pbaq where there could be a 6s2 configuration. In more covalent Pbn compounds and most Sn11 compounds there are stereochemically active lone pairs—indeed some EX2 and ER2 compounds of Ge and Sn can act as donor ligands. 

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