SN Ligands

Taking the curves of oxygen, sulfur and fluorine in Fig. 2 as a reference it seems that a linear correlation can be established between the c.n. and the bond distances (c.n. running from 3 to 8). A rise of the c.n. by one unit increases the mean Sn-ligand distance by about 10 pm ... 

T<155) " Sn Mossbauer spectra of Sn[N(SiMe3)2]2, Sn[NCH2CH2]2 and [Sn(NMe2)(lt-NMe2)]2 have been recorded " those of Sn[(NPr )2CjijHg-l,8] (98 < T < 255) were used to study the Sn-ligand bond flexibility in this compound, which has an... 

The physical properties of some bismuth complexes containing Si, Ge and Sn ligands are listed in Table 23. 

Several alkyl aryl ketones were reduced with PMHS in the presence of a complex prepared in situ consisting of Sn(0S02CF3)2 and a nitrogen-based ligand Pybox-Ph [5] (substrate Sn ligand= 10 1 1) in methanol at room temperature to give the chiral products in up to 58% ee [38]. 

The major types of complex containing Si,171 Ge, or Sn ligands are those with SiR3, GeR3, and SnR3 groups that are similar in stoichiometry to those of carbon compounds. They can be obtained by reactions such as... 

Scheme 33 Coordination of the SNS ligand with Cr(III) and Cr(II) precursors and reactivity toward various organoaluminum reagents...

We recendy reported a theoretical work on the SNS-Cr system in order to elucidate the oxidation state of the active chromium species with a consideration of the deprotonation of the SNS ligands (Yang et al., 2011). As depicted in Scheme 3.12, four molecular models Q—T were constructed for the typical SNS-Cr catalyst system. Cr(I) and Cr(II) were considered as the two most plausible oxidation states of the chromium center. Models Q and R are two active species without ligand deprotonation, while S andT were designed with consideration of SNS ligand deprotonation. 

---