کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1307668 975149 2011 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Ring folding in cyclopentadienyl diazabutadiene complexes of group 4 and 5 transition metals
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Ring folding in cyclopentadienyl diazabutadiene complexes of group 4 and 5 transition metals
چکیده انگلیسی

The syntheses of CpM(i-PrDAB)2 (M = Nb, Ta; Cp = (C5H5); i-PrDAB = bis-isopropyl-1,4-diazabuta-1,3-diene) are reported. Both show fluxional NMR spectra indicating that the two DAB rings differ. The X-ray crystal structure of CpNb(i-PrDAB)2 shows one ring to be more folded than the other. Density functional calculations have been used to investigate the degree of folding of the chelate ring in the compounds Cp2M(R-DAB), (M = Ti, Zr, Hf, Nb, Ta; R = H, i-Pr; DAB = 1,4-diazabuta-1,3-diene) and CpM(R-DAB)2 (M = Nb and Ta). For Cp2M(R-DAB) the group 4 compounds all have folded rings whereas the Nb and Ta compounds have planar rings. In all compounds the rings are reduced and the folding is driven by the electron number requirements of the metal centre.

Diazabutadiene rings when folded on coordination to a metal are acting as LX2 ligands with donation from the filled π3 orbital to the metal via the N atoms.Figure optionsDownload as PowerPoint slideResearch highlights
► The new compounds CpM(i-PrDAB)2 (M = Nb, Ta) have been synthesized.
► Folded MDAB rings are investigated in these and Cp2MDAB complexes by DFT.
► The origin of folding is interaction of the metal with the pπ electrons on the Ns.
► The C–C backbone of the DAB ligand is not coordinated to the metal.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Inorganica Chimica Acta - Volume 369, Issue 1, 15 April 2011, Pages 120–125
نویسندگان
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