Synthesis of ansa-[n]Silacyclopentadienyl–Cycloheptatrienyl–Chromium Complexes (n = 1, 2): Novel Precursors for Polymers Bearing Chromium in the Backbone
✍ Scribed by Alexandra Bartole-Scott; Holger Braunschweig; Thomas Kupfer; Matthias Lutz; Ian Manners; Thi-loan Nguyen; Krzysztof Radacki; Fabian Seeler
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 314 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0947-6539
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Reaction of [(η^5^‐C~5~H~4~Li)(η^7^‐C~7~H~6~Li)Cr]⋅tmeda with a variety of dialkyl(dichloro)silanes in aliphatic solvents afforded the corresponding [1]silatrochrocenophanes. Structural characterization by X‐ray diffraction analysis of the [1]silatrochrocenophanes bearing Me~2~Si, (__i__Pr)~2~Si, and silacyclobutane bridges revealed tilt angles α of 15.56(12)°, 15.8(1)°, and 16.33(17)°, respectively. Analogously, a [2]silatrochrocenophane (6) was prepared in excellent yield by reaction of [(η^5^‐C~5~H~4~Li)(η^7^‐C~7~H~6~Li)Cr]⋅tmeda with 1,2‐dichloro‐1,1,2,2‐tetramethyldisilane. This complex also was characterized structurally and exhibited a tilt angle α of 2.60(15)°. The [1]silatrochrocenophane bearing the Me~2~Si bridge underwent facile and regioselective carbon–silicon bond cleavage with [Pt(PEt~3~)~4~] to give a very high yield of an oxidative addition product. The ring‐opening polymerization of these novel [1]silatrochrocenophanes afforded ring‐opened chromium‐based polymers.