The crystal structures of NSF₃ and (NSF₂N(CH₃)CH₂–)₂: How short is the ‘Crystallographic’ NS triple bond

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• 作者：Tobias Borrmann ; Enno Lork ; Rü ; diger Mews ; Simon Parsons ; Jan Petersen ; Wolf-Dieter Stohrer ; Paul G. Watson
• 关键词：Sulfur– ; nitrogen chemistry ; Fluorine chemistry ; X-ray crystal structures ; Bonding ; Thazyl chemistry ; Intermolecular interactions
• 刊名：Inorganica Chimica Acta
• 出版年：2008
• 出版时间：15 January 2008
• 年：2008
• 卷：361
• 期：2
• 页码：479-486
• 全文大小：484 K

文摘

The synthesis of the first unequivocally characterised bis(difluorothiazyne), [NSF₂N(CH₃)CH₂–]₂ is reported. The crystal structures of this and NSF₃ are also reported. NSF₃ has the same geometrical parameters, within error, as it does in the gas phase. PIXEL calculations show that the principal interactions in its crystal structure are SNSN dipolar contacts, which form chains with SN = 3.533(2) Å. These contacts are reminiscent of those observed in the crystal structures of ketones. The exchange of a fluorine by a dialkylamino group has almost no influence on the NS bond distance while the SF bonds are significantly elongated. This behaviour is explained by negative hyperconjugation and confirmed by experimental data (as far as available) and quantum chemical calculations for NSF_n(NMe₂)_3−n and NSF_nPh_3−n (n = 1–3).