Sn-donor Ligands

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. 

The preparation of a series of ferrocenyl carbene complexes [(CO)5CrC(X)-C5H4FeC5H5] (X = O - NMe4% OMe, OEt, NH2, NMc2, or NC4H8) has been reported. The presence of a ferrocenyl group adjacent to the carbene 

The new class of carbene complexes, acyloxy-carbenes [(CO)sCrC(X)OAc] (X = 2-furyl or CH2SiMe3) have been isolated. These compounds extend the synthetic range of these carbene systems and afford the nitrile [(CO)5CrNCC4-H3O] and isonitrile [(COijCrCNMe], respectively, with HN3.  

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Group IV Donors. C-Donor and Sn donor ligands. A series of new isocyanide complexes [IrH2X(p-MeC6H4NQ(AsPh3)2] (X = F, Cl, Br, I, or N3) has been prepared by treating the corresponding trihydrides with I.r. and... 

Table 8 Comparison of Sn-N bond lengths in selected organotin(IV) compounds containing N) donor ligands...

The preference for the +2 over +4 oxidation state increases down the group, the change being due to relativistic effects that make an important contribution to the inert pair. The inert pair concept holds only for the lead ion Pb2+(aq), which could have a 6s2 configuration. In more covalent Pb11 compounds and most Sn11 compounds there are stereochemically active lone pairs. In some MX2 (M = Ge or Sn) compounds Ge and Sn can act as donor ligands. 

Addition reactions are also known, both across the polar Sn—O bond and at the metal center. With R2SnO, a telomerization reaction takes place in which the size of the heterocycle can be enlarged in a controlled way [Eq. (55)] (223). Donor ligands, for example, pyridine (Py),... 

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