Stannynes

In recent years, the first distannynes have been obtained. Reduction of 2,6-di(2,6-diisopropylphenyl)phenyltin(ll) chloride (Ar SnCl) or 2,6-di(2,4,6-triisopropylphenyl)phenyltin(n) chloride (ArSnCl) with sodium or potassium has given not only the stannynes Ar Sn=SnAr and ArSn=SnAr, but also the radical anion [ArSn=SnAr, and the dianions [ ArSn=SnAr] and [Ar Sn=SnAr ]=.534 The properties of the Ar compounds are as shown in Table 11. 

Many experimental and theoretical studies have been made of the chemistry of triple-bonded compounds of heavier Group 14 elements. " Recently, a series of homonuclear acetylene analogs of heavier Group 14 elements have been isolated as stable compounds (see Section 2.9.6). ° However, no stable het-eronuclear analogs, e.g. stannyne, have been reported so far. 

The generation of stannyne 58 by the photolysis of diazomethyl-substituted stannylene 57 was reported by Kira et al. (Scheme 2.9.22). The formation of 59 is explained by the intermediacy of stannyne 58, followed by the intramolecular insertion of the carbene moiety of 58 into the proximate methyl C—H bond of the isopropyl group. This result afforded evidence not only for the generation of 58 but also for its high carbene-like reactivity. 

Advances in techniques include sophisticated NMR methods, both in solution and the solid-state, and computational methods, and these, coupled with X-ray diffraction and other established methods, have been applied to the study of a wide variety of structures. Topics covered in the book include Sn(II) clusters, tin Zintl ions, Sn(II) heterobimetallic compounds, RsSn+ cations, stannylenes (R2Sn ), stannenes (R2Sn=SnR2 and R2Sn=CR2), stannynes (RSn=SnR), organotin oxide, carboxylate and sulfonate clusters, dendrimers and macrocycles, organotin polymers, Sh-tt interactions, unusual bondings and structures, and compounds with non-linear optical properties. 

This elimination of the picoline, generates the Sn 2-C(SiMe3)2C5H4N fragment, which coordinates to the cluster as a //-stannyne complex, as shown in Fig. 22. 

The remaining hydride remains coordinated to the cluster, bridging two of the framework osmium atoms. In terms of the electron count, this electron-precise cluster has 45 cluster valence electrons from the Os3(CO)ioH fragment, and thus three are contributed, as required, by the stannyne group. Notable features of the structure are (i) the appreciable lengthening of the Os Os distance bridged by the... 

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