Linear Oligostannanes

Polystannanes would be expected to possess even more o-delocalised structures, as suggested by studies of linear oligostannanes with up to six tin... 

SCHEME 12. Synthetic strategy to prepare oligostannanes with up to 15 tin atoms in the linear chain... 

Despite the elegant nature of this chemistry, the sequence is cumbersome, since two steps are required in the chain growth step and the synthesis and purification of air-sensitive materials is time-consuming and lowers the overall yield of oligomeric products. A simple modification of the above synthetic strategy leads to the systematic construction of oligostannanes up to 15 tin atoms in the linear chain as shown in Scheme 3.8.2. ... 

The electronic spectra of the linear oligostannanes " e.g. for the homologous series Et3Sn-(SnEt2)n-SnEts, (n = 0 ) are detailed in Tables 3.8.2 and 3.8.3. They exhibit a systematic red shift of the lowest energy transition, which is associated with a cr-cr transition, upon increasing the chain length. Eor example, the T- ax for perethylated distannane is red shifted from 232 nm to 325 nm for hexastannane. 

Shibata, K., Weinert, C. S. and Sita, L. R. (1998) Deconvoluting steric and electronic substituent effects on the properties of linear oligostannanes Synthesis and characterization of a new series incorporating the (Bu2Sn)-Sn-t group, Organometallics 17,2241-2248. 

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