The versatile chemistry of niobium pentachloride with aliphatic amines: Aminolysis, metal reduction and C-H activation

详细信息    查看全文

• 作者：Riccardo Bondi^a ; Fabio Marchetti^a ; ^{fabio.marchetti1974@unipi.it" class="auth_mail" title="E-mail the corresponding author} ; ; Guido Pampaloni^a ; Stefano Zacchini^b
• 关键词：Niobium pentachloride ; Aliphatic amines ; C&ndash ; H bond activation ; Ammonium salts ; X-ray structure
• 刊名：Polyhedron
• 出版年：2015
• 出版时间：4 November 2015
• 年：2015
• 卷：100
• 期：Complete
• 页码：192-198
• 全文大小：941 K

文摘

The reactions of NbCl₅ with limited amounts (1–2 molar equivalents) of a series of primary, secondary and tertiary amines were investigated in dichloromethane as solvent. The 1:1 reaction of NbCl₅ with NHEt₂ cleanly afforded an equimolar mixture of [NbCl₄(NEt₂)]₂, 1, and [NH₂Et₂][NbCl₆], 2a; the former product constitutes the first example of structurally characterized Nb(V) chlorido–amido complex. The ammonium salts [NH₃ⁿPr][NbCl₆], 2b, and [NH₂ⁱPr₂][NbCl₆], 2c, were isolated in 20–30% yields from the 1:1 reactions of NbCl₅ with NH₂ⁿPr and NHⁱPr₂, respectively. Cα–H bond activation and Nb(V) to Nb(IV) reduction took place in the reactions of NbCl₅ with NR₃ (R = Bz, Et; Bz = CH₂Ph). The iminium salt [(PhCH₂)₂Ndouble bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CHPh][NbCl₆], 3, and the ammonium ion [NH(CH₂Ph)₃]⁺ were identified as the prevalent species generated from the 1:1 NbCl₅/NBz₃ interaction. [NHEt₃][NbCl₆], 4, and [NHEt₃]₂[NbCl₆], 5, were isolated in moderate yields from, respectively, the 1:1 and 1:2 molar reactions of NbCl₅ with NEt₃. The solid state structures of 1, 2a, 3, 4 and 5 were ascertained by single crystal X-ray studies.