Bridged Ditins

When conducted under mild conditions, or with only one equivalent of tin tetrachloride, the dealkylation process can be stopped after reaction of one tin center, in the case of 87. The presence of the electron-withdrawing trichlorotin group in the / ara-position of the ring deactivates the metalated aryl carbon bond to such extent that the intermediate bearing a trichlorotin and a tricyclohexyltin group can 

I wish to thank Professor T. Toupance for helpful discussions and Dr. M. Lahcini, Dr. P. Jaumier, Dr. H. Riague, Dr. G. Vilaga, Dr. H. Elhamzaoui, Dr. G. Prabusankar, and M-C. Rascle for their crucial contributions to various aspects of this work, as well as Professor M. Biesemans, Professor E.R.T. Tiekink, Professor R. Willem, and Dr. H. Allouchi for their fruitful collaboration. 

Brinker and G. W. Scherer, Sol-Gel Science, Academic Press, London, 1990. 

Gomez-Romero and C. Sanchez, Functional Hybrid Materials, Wiley-VCH, Weinheim, 2003. 

Schumaim and 1. Schumaim, Organotin Compounds in Gmelin Handbook of Inorganic Chemistry, H. Bitterer, (Ed), Springer-Verlag, Berlin, 1979, p 210. 

---

The spacer-bridged ditin compound MeCl2Sn(CH2)3SnCl2Me239 was reported to contain, in the solid state, hexacoordinated tin atoms as a result of strongly unsymmetrical intermolecular Sn—Cl—Sn bridges with Sn—Cl distances in the range of 2.381(1)—3.484(1) A, giving rise to the formation of a sheet-like polymer. 

In a first attempt and with the results of the non-symmetrically substituted tetraorganodistannoxanes 1 and 2 in mind, we looked at the reaction of the trimethylene-bridged ditin compound RCl2Sn(CH2)3Sn CI2R (36, R = Me3SiCH2) with cycto-(/-Bu2SnO)3(Scheme 2.10.10). 

The hexanuclear organotinoxo cluster 90 that is based on a spacer-bridged ditin compound is obtained by reaction of thelO-membered ring cycto-CH2[CH2Sn(Cl2)CH2SiMe2]20 with cycto-(t-Bu2SnO)3 (Scheme 2.10.17). 

Organically bridged ditin hexaalkynides 2 are therefore useful sol-gel precursors of mesoporous (or nanoporous) tin dioxide materials. Indeed, for each sample studied, theN2 adsorption-desorption isotherm is a type IV isotherm with a type H2 hysteresis loop, which is typical of mesoporous solids, according to the lUPAC classification (Figure 3.2.9). ... 

For another example of a pentacoordinate ditin complex, 2,6-(i-Pr)2C5H3N(SnMe2Cl)2 Pyr, which contains one bridged chlorine atom, see Reference 355h. 

Ditin hexa-acetate (CH3COO)6Sn2 is formed by the action of acetic acid upon hexa-phenylditin at 120°. It is quite a stable compound, and is believed to have the structure illustrated in Fig. 15, where two bridging acetate groups are present in addition to the... 

---