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End-On Bridging Dinitrogen Complex of Scandium.
- Source :
-
Journal of the American Chemical Society . 10/25/2017, Vol. 139 Issue 42, p14861-14864. 4p. - Publication Year :
- 2017
-
Abstract
- The first (N=N)2- complex of a rare-earth metal with an end-on dinitrogen bridge, {K-(crypt)}2{[(R2N)3Sc]2[μ-η1:η1-N2]} (crypt = 2.2.2-cryptand, R = SiMe3), has been isolated from the reduction of Sc(NR2)3 under dinitrogen at -35 °C and characterized by X-ray crystallography. The structure differs from the characteristic side-on structures previously observed for over 40 crystallographically characterized rare-earth metal (N=N)2- complexes of formula [A2Ln(THF)x]2[μ-η2:η2- N2] (Ln = Sc, Y and lanthanides; x = 0, 1; A = anionic ligand such as amide, cyclopentadienide and aryloxide). The 1.221(3) Å N-N distance and the 1644 cm-1 Raman stretch are consistent with the presence of an (N=N)2-bridge. The observed paramagnetism of the complex by Evans method measurements is consistent with DFT calculations that suggest a triplet (3A2) ground state in D3 symmetry involving two degenerate Sc-N2-Sc bonding orbitals. Upon brief exposure of the orange Sc3+ bridging dinitrogen complex to UV-light, photolysis to form the monomeric Sc2+ complex, [K(crypt)][Sc(NR2)3], was observed. Conversion of the Sc2+ complex to the Sc3+ dinitrogen complex was not observed with this crypt system, but it did occur with the 18-crown-6 (crown) analog which formed {K(crown)}2{[(R2N)3Sc]2[μ-η1:η1 N2]}. This suggests the importance of the alkali metal chelating agent in the reversibility of dinitrogen binding in this scandium system. [ABSTRACT FROM AUTHOR]
- Subjects :
- *SCANDIUM
*NITROGEN
*X-ray crystallography
*PARAMAGNETISM
*PHOTOLYSIS (Chemistry)
Subjects
Details
- Language :
- English
- ISSN :
- 00027863
- Volume :
- 139
- Issue :
- 42
- Database :
- Academic Search Index
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 125899019
- Full Text :
- https://doi.org/10.1021/jacs.7b08456