New diorganotin compounds (RCl2Sn)2(CR‘2) n [R = (SiMe3)2CH; R‘ = Me, H; n = 1−3] linked by various spacers have been synthesized. These react with sodium hydroxide or (t-Bu2SnO)3 to give (R(O)Sn)2(CR‘2) n . Compounds 8 (R‘ = Me, n = 1), 9 (R‘ = H, n = 2), and 10 (R‘ = H, n = 3) contain four-coordinate tin atoms. Compound 9 undergoes a reversible hydrolysis reaction from which a solid containing three ditin units has been isolated. Evidence is presented for the existence in solution of monomeric four-coordinate tin compounds (RXSn)2(CH2)3O [R = (SiMe3)2CH, X = Cl, OH]. Crystal structures for monomeric ditin precursors 2,2-bis[bis(trimethylsilyl)methyldichlorostannyl]propane (3) and 1,2-bis[bis(trimethylsilyl)methyldichlorostannyl]ethane (6), for dimeric units 1,3,5,7-tetrakis[bis(trimethylsilyl)methyl]-9,9,10,10-tetramethyl-2,4,6,8-tetraoxa-1,3,5,7-tetrastannaadamantane (8), 1,3,7,9-tetrakis[bis(trimethylsilyl)methyl]-2,8,13,14-tetraoxatricyclo[7.3.1.13.7]-1,3,7,9-tetrastannatetradecane (10), and 2,6-difluoro-2,6-bis[bis(trimethylsilyl)methyl]-1-oxa-2,6-distannacyclohexane dimer (12), and for trimeric units {O[(RSn(CH2)2SnR)OH]OH}3·2H2O (9a) are reported.

The new bulky silicon-containing ditin precursor p-(RCl2SnCH2SiMe2)2C6H4 (R = CH2SiMe3 (4)) has been synthesized and further reacted to form a unique double ladder {[p-(R(Cl)SnCH2SiMe2)2C6H4]O}4 (6). The two layers within 6 are twisted with respect to one another, resulting in a helical motif and a total absence of molecular symmetry so that there are eight chiral tin atoms within the system. The structure is compared to the double ladder {[m-(R(Cl)SnCH2CH2)2C6H4]O}4 (11), which was prepared from the less sterically demanding ditin precursor m-(RCl2SnCH2CH2)2C6H4 (10). The two layers within 11 are parallel, and the molecule contains only two kinds of tin atom.

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The synthesis and molecular structure are reported of the first example of a diorganotin oxide, {p-[R(O)SnCH2SiMe2]2C6H4}3 (3) (R = (Me3Si)2CH), in which two six-membered Sn3O3 units are linked by three −CH2Si(Me)2C6H4Si(Me)2CH2− spacers.

The reaction of Me 3 SiCH 2 Cl 2 Sn(CH 2 ) 3 SnCl 2 Ph (6) with (tBu 2 SnO) 3 gave a statistical mixture of the corresponding tetraorganodistannoxanes whereas the reaction of the spacer-bridged ditin tetrachlorides RCl 2 Sn(CH 2 ) 4 SnCl 2 R (3, R = Me 3 CCH 2 ; 4, R = Me 2 CHCH 2 ; 10, R = Me 3 SiCH 2 ) with the polymeric spacer-bridged ditin oxides [R(O)Sn(CH 2 ) 4 -Sn(O)R] n (7, R = Me 2 CHCH 2 ; 8, R = Me 3 CCH 2 ; 11, R = Me 3 SiCH 2 ) provided the mixed double ladder compounds [ ‡] This work contains parts of the Diploma thesis of M. Mehring, Dortmund University, 1995, and of the planned Ph. D. thesis of I. Paulus. [a]