Stannatrane

This configuration has not yet been demonstrated by X-ray studies, perhaps due to the difficulty in obtaining good crystalline samples. Recently, Tzschach reviewed the whole field of intramolecularly pentacoordinate, organotin compounds (198), including the stannatranes. 

A rare case of the formation of the first metal-bound stannatrane complex 187 has been reported as the result of the reaction between triethanolamine and organometallic compound 186 (Equation 11) <1999CC837>. As confirmed by a X-ray single crystal diffraction study, the Sn-N distance is significantly shorter compared to the sum of the tin(iv) and nitrogen van der Waals radii. 

Hypervalent intramolecular organotin compounds are stannatranes RSn(OCH2CH2)3N... 

Reaction between Me2N(CH2)3Sn(OPh)Ph2 (239e) and TEAA proceeds smoothly due to the high reactivity of hypervalently activated organotin compounds and gives stanna-trane 432 (R = (CH2)3NMe2)644. Its 5119Sn NMR appears between those of stannatranes with penta- and hexacoordinated tin atoms. This fact was interpreted as a result of a fast equilibrium on the NMR time scale. 

The first stannatrane containing a tin-metal bond, the osmium derivative 450, was synthesized from TEAA and a triiodostannyl osmium complex (Scheme 20)878. 

SCHEME 20. Synthesis of stannatrane 450 containing the tin—osmium bond... 

TABLE 62. Selected structural parameters of stannatranes XSn(OCH2CH2)3N and their tricyclic analogues... 

This section covers heterocyclic rings which contain lone pair-bearing heteroatoms within the ring so disposed as to enable additional coordination to tin, thereby generating a collection of fused, tin-containing heterocycles. These are shown in 76 and 77, bicyclic or diptych structures, and 78, a tricyclic or triptych arrangement. The term stannatrane is also commonly used in discussions of these latter systems. These compounds... 

Selected Structural Data for Stannatranes and Related Compounds... 

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