Two synthetic approaches for the preparation of tin(ii) dications.

Examples of tin dications without closer contacts to the anion are rare, as are straightforward routes to weakly coordinated tin(ii) dication salts. Here we report on the synthesis of [Sn(MeCN)6][Al(ORF)4]2 (RF = C(CF3)3) via NO+-oxidation of tin metal. Subsequently, [Sn(MeCN)6][Al(ORF)4]2 was used to prepare the mixed coordinated [Sn(pyr)2(MeCN)4][Al(ORF)4]2 and [Sn(PPh3)2-(MeCN)5][Al(ORF)4]2·MeCN. Additionally, [Sn(dmap)4][Al(ORF)4]2 was prepared via a reaction of dmap with [SnCp][Al(ORF)4]. The generality of the formation of tin(ii) dications by reacting [SnCp]+ and L to give [SnLx]2+ and SnCp2 was investigated using DFT calculations. Extensions to [ECp*]+ cations (E = Si, Ge, Sn, and Pb) are also suggested to be useful for the preparation of E(ii) dications.

The Parent Cyclopentadienyltin Cation, Its Toluene Adduct, and the Quadruple-Decker [Sn3 Cp4 ]2.

Truly cationic metallocenes with the parent cyclopentadienyl ligand are so far unknown for the Group 14 elements. Herein we report on an almost "naked" [SnCp]+ cation with the weakly coordinating [Al{OC(CF3 )3 }4 ]- and [{(F3 C)3 CO}3 Al-F-Al{OC(CF3 )3 }3 ]- anions. [SnCp][Al{OC(CF3 )3 }4 ] was used to prepare the first main-group quadruple-decker cation [Sn3 Cp4 ]2+ again as the [Al{OC(CF3 )3 }4 ]- salt. Additionally, the toluene adduct [CpSn(C7 H8 )][Al{OC(CF3 )3 }4 ] was obtained.