Formation of a radical tricationic tetraborane(4) by hydride abstraction from sp3-sp3-hybridized diboranes
The formation, electronic structure, and reactivity of the recently-reported radical tricationic tetraborane [B4(hpp)4]·3+ (hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate), which features a planar rhomboid B4 unit and bridging bicyclic guanidinate (hpp) substituents, is reported. New exp...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
06 August 2016
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| In: |
European journal of inorganic chemistry
Year: 2016, Issue: 25, Pages: 4090-4098 |
| ISSN: | 1099-0682 |
| DOI: | 10.1002/ejic.201600629 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1002/ejic.201600629 Verlag, lizenzpflichtig, Volltext: https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/ejic.201600629 
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| Author Notes: | Sebastian Litters, Elisabeth Kaifer, and Hans-Jörg Himmel |
| Summary: | The formation, electronic structure, and reactivity of the recently-reported radical tricationic tetraborane [B4(hpp)4]·3+ (hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate), which features a planar rhomboid B4 unit and bridging bicyclic guanidinate (hpp) substituents, is reported. New experiments show that the tetraborane could be synthesized by hydride abstraction either in a very fast reaction from the electron-rich sp3?sp3-hybridized diborane [HB(hpp)]2, or in a very slow reaction from the cationic, less electron-rich sp3?sp3-hybridized diborane [HB(hpp)2BPCy3]+. The results argue for an electron-transfer in the rate-determining step of a complex reaction sequence. Quantum chemical calculations highlight the role of the hpp substituents for the stabilization of the radical tricationic tetraborane [B4(hpp)4]·3+. Further analysis shows that [B4(hpp)4]·3+ is highly reactive, and especially a very strong electrophile. This reactivity makes the compound very interesting because boron atoms in such a low oxidation state (<2) are expected to be strong nucleophiles. |
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| Item Description: | Im Titel ist die Zahl "3" jeweils hochgestellt Gesehen am 27.05.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1099-0682 |
| DOI: | 10.1002/ejic.201600629 |