Synthesis and Structure of a Hypercoordinate Silicon-Bridged [1]Ferrocenophane

Abstract

The first hypercoordinate silicon-bridged [1]ferrocenophane shows a pronounced Si-N interaction, a pseudo-trigonal-bipyramidal geometry at the bridging silicon atom, an elongated Si-Cp bond trans to the amino group, and an unusually long Fe-Si distance in comparison to the tetracoordinate analogues.

Strained Metallocenophanes and Related Organometallic Rings Containing π‐Hydrocarbon Ligands and Transition‐Metal Centers

“…[70] The nature of the substituents at silicon does not result in large structural variations between the sila [1]ferrocenophanes (Table 3), which generally possess tilt angles between 19 and 228 and corresponding strain energies of 70-80 kJ mol À1 . [60] Accordingly, ROP is a viable route for obtaining high-molecular-weight (M n % 10 4 -10 5 ) polymers from many of these compounds.…”

“…(8)] and their ring-opened polymers have been reported by the Manners and Hatanaka groups. [70,74,75] The significant structural changes upon hypercoordination of the silicon center include a longer FeÀSi separation, a change to a trigonal bipyramidal geometry at the silicon atom accompanied by narrower q angles and elongated C ipso ÀSi bonds. [74,75] In 17, the weaker C ipso ÀSi bond is easily cleaved in the presence of a cationic catalyst to initiate ROP, unlike the analogous tetracoordinate sila [1]ferrocenophane, which is inert under similar conditions.…”

“…Preparation of 18 in higher yield (which allowed for Scheme 2. Selected substitution reactions of chloro-substituted sila [1]ferrocenophanes (10 [70] (Ar = C 6 H 4 -2-CH 2 NMe 2 ); 11-12; [55] 13; [71,72] 14-16 [73] ). …”

Polyferrocenylsilane‐Based Polymer Systems

“…20.61(8) [27] SifcMe 21.3 [21] Si(fc) [a] 19.4(2) [27] SiH 2 19.1(1) [22] SiMe(o-C 6 H 4 -CH 2 NMe 2 ) [b] 21.27(1) [28] SiPh 2 19.2 [23] Si(OtBu) 2 20.3 [29] SiMeCl 19.37(32) [24] SiMeN{(CH 2 ) 3 SiMe 2 -(CH 2 ) 2 SiMe 2 } 21.0(2) [30] [a] Spirocyclic. [b] À possesses a tilt angle of 24.4(5)8 and undergoes both thermal and PtCl 2 -catalyzed ROP.…”

Synthesis and Solution Self‐Assembly of Polyisoprene‐block‐poly(ferrocenylmethylsilane): A Diblock Copolymer with an Atactic but Semicrystalline Core‐Forming Metalloblock

“…15 Hypercoordinate silicon-bridged [1]ferrocenophanes can also be synthesised from chlorosila[1]ferrocenophanes Fe(η 5 -C5H4)2SiRR' (R = R' = Cl or R = Me, R' = Cl) and Li or Fe(η 5 -C5H4)2SiCl(CH2Cl) and N-methyl-N-(trimethylsilyl)acetamide. 16,17 These pentacoordinate species show a pronounced Si-N or Si-O interaction with a pseudo trigonal bipyramidal geometry at the bridging silicon atom in the solid state. 17,18 In addition, spirocyclic sila[1]ferrocenophanes can be prepared in a similar manner to that already described: for example the reaction of Fe(η 5 -C5H4Li)2·TMEDA with Cl2Si(CH2)3 gives silacyclobutyl[1]ferrocenophane (Scheme 2 [B]).…”