Polystannanes properties

Sita, Lawrence R., Structure/Property Relationships of Polystannanes. 38 189... 

Most of the reactions that can be used to prepare distannanes can be extended to the preparation of oligo- and polystannanes, which have attracted interest for potential use in electronic and optical devices.455 The structures of the products are not necessarily those of completely linear catenanes, (R2Sn) , and different degrees of branching confer different properties. The formation of polymers is also frequently accompanied by the formation of cyclic pentamers or hexamers, and samples prepared by different methods may show substantially different properties. 

This review will focus on the NMR properties of Zintl ion complexes, namely the solution properties of the ions where E = Si, Ge, Sn, Pb, and the products derived from those clusters. Closely related clusters prepared by other means, such as the recent, elegant organo polystannane work of Schnepf, Power, Huttner, and Fischer, are briefly mentioned but are not the focus of this review. Related overviews of dynamic organometallic complexes [1,2] and the stmcture and bonding of Zintl ions [3-5] can be found in previous reviews and in other chapters of this book. 

Sita LR (1995) Stracture/property Relationships of Polystannanes. In Stone EGA, West R (eds) Advances in organometallic chemistry, vol 38. Academic, London, pp 189-243... 

Polystannanes have been shown to display very interesting properties. They are highly photosensitive and exhibit photobleaching behaviour and on UV irradiation depolymerise to yield cyclic oligomers. The materials are thermally stable to 200-270 °C in air and at more elevated temperatures function as precursors to Sn02. " By using rhodium catalysts, branched polystannanes have been prepared. 

The polysilanes can be regarded as one-dimensional analogs to elemental silicon, on which, of course, nearly all of modem electronics is based. The photophysical behavior of polysilanes is not approached by any other materials, save for the less stable and more costly polygermanes and polystannanes. The remarkable properties of polysilanes have led to intense interest, and to numerous proposed high-tech applications. But the great promise of polysilanes as materials has yet to be realized. Their only commercial use at present is as precursors to silicon carbide ceramics, an application which takes no advantage of their optical or electronic properties. 

Highly coordinated tin enolates, reactivity, 9, 362 High-molecular weight polystannanes, preparation and properties, 12, 381... 

As described in Section II.E, polystannanes, which can be prepared by the Wurtz coupling of chlorostannanes with alkali metals and by the dehydrocoupling of hydrostannanes, exhibit intriguing physical properties. The Sita group reported a peculiar polymerization of -Bu2SnH2 with a RhH(CO)(PPh3)3 catalyst [Eqs. (21a) and (21b)].63... 

In this section we give a comparative overview on the recent developments in the preparation of polystannanes and discuss their properties. 

The preparation of these higher molecular weight polystannanes, and the demonstration that they possess a chemical and mechanical integrity similar to that of the polysilanes (they are, however, much more photosensitive than polysilanes), will no doubt stimulate the further study of their properties and methods for their synthesis. 

See for example L. R. Sita, Adv. Organomet. Chem. 1995,38,189 (a review on the structure and property relationships of polystannanes). 

Currently, there is growing interest in polymers the frameworks of which are constructed from the Group 14 elements silicon, germanium and tin. Several reviews on polysilanes have appeared in the literature . In the first section of this article we focus on recent developments in the chemistry of polygermanes and polystannanes. The chemistry and structure-property relationship of oligostannanes and low molecular weight polystannanes was the subject of earlier reviews . ... 

---