Synthesis of 6,6,~,7.13.13,14.14-0ctamethyl-6,?,13,14-tetrasiladispiro[4.2.4.2]tetradeca-l,3,9.11-tetraene and Its Application in the Chemistry of E Complexes of pand d-Block Elements The title compound 2 can be synthesized either by reaction Me5C5Fe(acac), with Me5C5GeC1, with SnCl,, and with PbC12, of ([C5H,SiMe2SiMezC5H5]z-2 L i f ) with XSiMe2SiMe2X or lead to the metallocenes 6, ?, 8, and 9; in all these complexes by an intermolecular nucleophilic substitution reaction be-the disilane bridges are in 1,2-position. The binuclear cobalt tween two molecules of ([XSiMezSiMezC5H5]-Li+). Isomers complex 10, in which the cyclopentadienyl rings are conof 2 with allylic hydrogen atoms arise from silatropic rear-nected with each other by disilane bridges in 1,3-position, can rangements and therefore show "cyclopentadiene reactivity". be synthesized by the reaction of 2 with CO~(CO)~. The results Reaction of the monoanion of 2 with FeC1, yields the ferrocene of single-crystal X-ray structure analyses of 6 and 10 are pre-4. From the reaction of the dianion of 2 with Me5C5RuC1, sented. The possible conformations of the dianion of 2 are the binuclear ruthenium complex ? with Si -Si bridges in discussed.

Summary. 6,6,8,ferrocenophane 2 was obtained from the di(alkoxysilyl) ferrocene (H4CsSiMe2OR)2Fe (R = CH2CH2OCH2CH2OCH2CHEOMe ) by hydrolysis and subsequent intramolecular disiloxane formation. 2,2',3,Y,4,4',5,5',6,6,8,ferrocenophane 3 was formed by air oxidation of 2,2'3,3 ',4,4',5,5',6,6,7,7-dodecamethyl-6,7-disila[2]ferrocenophane. The crystal structures of both compounds were determined by single-crystal X-ray diffraction (2: a=8.5330 (10) Keywords. Ferrocenophane; Disiloxane unit.[3]Ferrocenophane mit Tetramethyldisiloxan-Br0cke: Synthese und Molekiilstruktur Zusammenfassung. 6,6,8,-ferrocenophan 2 entsteht aus dem Di(alkoxysilyl)ferrocen (H4CsSiMe2OR)2Fe ( R = C H 2 C H 2 O C H 2 C H 2 O C H 2 C H 2 O M e ) durch Hydrolyse und anschlieBende intramolekulare 2',3,Y,4,4',5,5',6,6,8,]ferrocenophan 3 wurde durch Luftoxidation yon 2,2 ',3,3',4,4',5,5',6,6,7,

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The pentamethyldisilanyl-substituted cyclopentadienes Me,CsH,,_,W,Mes), (for n = 0: 1 (m = 11, 2 (m = 2), 3 (m = 3), 4 (m = 4); for n = 1: 5 (m = l), 7 (m = 2),9 (m = 3); for n = 3: 13 (m = 11, 14 (m = 2); for n = 4: 15 (m = 1)) are accessible in good yields by treatment of the corresponding cyclopentadienyllithium compounds with MesSi,Cl. The mono-Me&-substituted species 1 and 5 are present only to a small extend in form of vinylic isomers and to a greater extend as isomers with the Me+,-group in allylic position; the latter possess a dynamic structure due to sigmatropic rearrangements. In the twice-Me&-substituted cyclopentadienes 2 and 7, the 5,5 and 2,5 isomers are observed, which can be interconverted by silatropic shifts; in addition, the presence of two vinylic isomers can be proved in the case of 2. In the cyclopentadiene species 3 and 9 with three MesSi, groups, only the 2,5,5 isomers can be detected by NMR spectroscopy. Compound 3 possesses a fluxional structure and can thus be deprotonated. On the other hand, 9 does not show a fluxional behaviour and thus cannot be deprotonated. The cyclopentadiene 4 with four MesSi, substituents possesses a static structure and cannot be deprotonated. The 2,3,5,5 position of the substituents is proved by an X-ray crystal structure analysis. Only two Me,.%, groups can be incorporated in the carbon skeleton of 1,2,4-trimethylcyclopentadiene, whereby compounds of the type 1,2,4_Me,C,H,_,(Si,Me,), (13: n = 1; 14: n = 2) are formed. Surprisingly, 14 cannot be deprotonated with "BuLi and KH, respectively. The reaction of Me,CsHLi with Me&Cl leads to the cyclopentadiene Me,C,HSi,Me, (15). Though compound 15 can be deprotonated, further reaction of the resulting anion with Me&Cl does not lead to the expected cyclopentadiene Me,Cs(Si,MesI, (16). On the other hand, 16 can be prepared by metallation of 14 with CsK and further reaction with CH,I. In contrast to 14, compound 4 cannot be deprotonated with CsK, the reaction of 4 with CsK and CH,I leads to 9 via Si-C bond splitting. The pentamethyldisilanyl-substituted pentamethylcyclopentadiene MesCsSizMe, (17) is obtained by reaction of Me&K with Me&Cl; compound 17 shows dynamic behaviour; the migration of the MesSi, group is slower than that of the MesSi group in MesCsSiMe,. Three EIMe, groups can be introduced stepwise into the 1,2,4-Me&H, molecule, as demonstrated by the exemplary synthesis of the cyclopentadienes 1,2,4-Me,C,H,_,(SiMe,), (10: n = 1; 11: n = 2) and 1,2,4-Me,C,(SiMe,),SnMe,

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.