In search for a pentacoordinated monoorgano stannyl cation

Alkylation of Sn(OCH2CH2NMe2)2 (1) by MeI or MeOTf leads to a mixture of quaternary ammonium salts by alkylation of the NMe2 moiety. Reaction of Sn(acac)2 (2) with MeOTf gives unexpected redistribution product Sn(acac)OTf (3), which is a rare example of mono acetylacetonato tin (II) derivatives. Pentacoordinated monoorgano stannyl cation PhSn(OCH2CH2NMe2)2+ was generated by salt metathesis from PhSn(OCH2CH2NMe2)2Cl (5) and Ag[Al(OCH(CF3)2)4] or Ag[B(C6F5)4]. This cation was not isolated due to its strong electrophilic nature. It abstracts substituents from aluminate and borate weakly coordinating anions (WCAs) leading to redistribution products [Al[OCH(CF3)2]2OCH2CH2NMe2]2 (6) and [Ph(C6F5)Sn(OCH2CH2NMe2)2][H2OB(C6F5)3] (9), respectively. Structures of 3 and 6 were established by single-crystal X-ray diffraction analysis.

Pentacoordinated monoorgano stannyl cation PhSn(OCH2CH2NMe2)2+ was generated by salt metathesis from PhSn(OCH2CH2NMe2)2Cl and Ag[WCA] (WCA = weakly coordinating anion Al(OCH(CF3)2)4- or B(C6F5)4-). It was not isolated due to its strong electrophilicity. Abstraction of anions OCH(CF3)2- and C6F5- from aluminate and borate WCAs takes place.Figure optionsDownload as PowerPoint slide