Application of ⁹³Nb NMR spectroscopy to (silox)₃Nb(X_n/L_m) complexes (silox = ^tBu₃SiO): Where does (silox)₃Nb(NN)Nb(silox)₃ appear?

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• 作者：Elliott B. Hulley ; Valerie A. Williams ; Kurt F. Hirsekorn ; Peter T. Wolczanski ; ^{ptw2@cornell.edu" class="auth_mail" title="E-mail the corresponding author} ; Kyle M. Lancaster ; ^{kml236@cornell.edu" class="auth_mail" title="E-mail the corresponding author} ; Emil B. Lobkovsky
• 关键词：Niobium ; NMR ; Dinitrogen ; Complex ; Quadrupolar
• 刊名：Polyhedron
• 出版年：2016
• 出版时间：8 January 2016
• 年：2016
• 卷：103
• 期：part_PA
• 页码：105-114
• 全文大小：1331 K

文摘

⁹³Nb NMR chemical shifts and linewidths are reported for the following 4-coordinate series of (silox)₃Nb(X_n/L_m) species: X_n/L_m = NNCH(SiMe₃), g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">NNT; O, 1g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">O; Cl₂, g class="boldFont">2g>–Cl₂; ¹³Cg border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">¹³CO, g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">¹³C¹³CO; CHCH₃, g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CHMe; CH₂, g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CH₂; CH(trans-CHg border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CHCH₃), g class="boldFont">1g>–t-C₄H₆; CH(trans-CHg border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CH(CH₂)₂Ph), g class="boldFont">1g>–t-C₅H₆Ph; CH(cis-CHg border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CHCH₃), g class="boldFont">1g>–c-C₄H₆; CH(cis-CHg border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CH(CH₂)₂Ph), g class="boldFont">1g>–c-C₅H₆Ph; (η-C₂H₄), g class="boldFont">3g>–C₂H₄; (κ²-C,C–CH₂CHCHCH₂), g class="boldFont">2g>–C₄H₆; (η²-CD₂g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CH(trans-2-Ph-^cPr)), g class="boldFont">3g>–VyPh^cPr; P⁻[Li(THF)_x]⁺, g class="boldFont">1g>–PLi; PH, g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">PH; PMe, g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">PMe; [(silox)₃Nb]₂(μ:η¹,η¹-N₂), g class="boldFont">1g>₂–N₂. Small scale syntheses of g class="boldFont">1g>g border="0" alt="double bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">NNT and g class="boldFont">2g>–C₄H₆ are given, and the preparation of g class="boldFont">1g>₂–N₂, is reported, along with its X-ray crystal structure, and electronic structure. Calculated (DFT) ⁹³Nb NMR chemical shifts correlate with the experimental values, and δ is found to be generally proportional to 1/X (X is Pauling electronegativity). This trend is derived from the paramagnetic contribution, which is governed by the second-order Zeeman effect, and estimated using the Average Excitation Energy (AEE) model.