Transformation of 3,4-Bis(isopropylidene)-2,5-dichloro-1,2,5-thiadiborolane into nido-2,4,5-Thiadicarbahexaborane(5) Derivatives – Formation and Computational Elucidation of a Thiadicarbanonaborane(8) with a ni-9 Configuration
✍ Scribed by Volker Beez; Peter Greiwe; Hans Pritzkow; Matthias Hofmann; Paul v. R. Schleyer; Walter Siebert
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 205 KB
- Volume
- 1998
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
1,2,5-thiadiborolane / nido-2,4,5-Thiadicarbahexaboranes(5) / Isomeres / Thiadicarbanonaborane(8) / IGLO
The 3,4-bis(isopropylidene)-2,5-dichloro-1,2,5-thiadiboro-refined X-ray structural data of 2d support the proposed skeletal structure. In addition to 2a, larger thiacarboranes lane (5b), obtained from 3,4-bis(dichloroboryl)-2,5-dimethyl-2,4-hexadiene ( ) and (Me 3 Si) 2 S, reacts with Li[RBH 3 ] (R = were detected by GC/MS and 11 B NMR. The structure of the nine-vertex cluster 6a could be identified by applying the H, C 6 H 5 , C 6 Me 4 H) to yield the corresponding derivatives of the nido-4,5-diisopropyl-2,4,5-thiadicarbahexaboranes 2.
ab initio/IGLO/NMR method. Geometry optimizations at the MP2(fc)/6-31G* level rule out the C s nido-SC 2 B 6 H 8 isomer 7. Replacements of the chlorine atoms in 5b with two hydrido, or with one hydrido and one aryl (phenyl or duryl) group, The C 2v structure of 6 consists of a nine-vertex cluster with two elongated B-B distances. As this 22e cluster 6 represents followed by the hydroboration of the isopropylidene substituents with RBH 2 (R = H, C 6 H 5 , C 6 Me 4 H) lead to four an exception to the Wade rules, the nature of the bonding of nine-vertex clusters with different electron counts is nido-2,4,5-thiadicarbahexaboranes (2a-d) in low yields. Their composition follows from MS and NMR data; not discussed.