Raman spectroscopy of the N–N bond in rare earth dinitrogen complexes. Issue 37 (4th March 2016)

• Record Type: Journal Article
• Authors: Fieser, Megan E.; Woen, David H.; Corbey, Jordan F.; Mueller, Thomas J.; Ziller, Joseph W.; Evans, William J.
• Is Part Of: Dalton transactions. Volume 45:Issue 37(2016)
• Page Start: 14634
• Page End: 14644
• Publication Date: 2016-03-04
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt04547a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Raman spectra have been collected on single crystals of over 20 different rare earth complexes containing reduced dinitrogen ligands to determine if these data will correlate with periodic properties or relative stability. Abstract : Raman spectra have been collected on single crystals of over 20 different rare earth complexes containing reduced dinitrogen ligands to determine if these data will correlate with periodic properties or relative stability. Four types of complexes were examined: [(C5 Me5 )2 Ln]2 (μ–η 2 :η 2 -N2 ), 1-Ln, [(C5 Me4 H)2 (THF)Ln]2 (μ–η 2 :η 2 -N2 ), 2-Ln, [(C5 H4 Me)2 Ln]2 (μ–η 2 :η 2 -N2 ), 3-Ln, and {[(Me3 Si)2 N]2 (THF)Ln}2 (μ–η 2 :η 2 -N2 ), 4-Ln . Although each of the complexes contains a side-on bound dinitrogen ligand that is formally (N2 ) 2−, the N–N bond distances determined by X-ray crystallography range from 1.088(12) to 1.305(6) Å. In the4-Ln series (Ln = Gd, Tb, Dy, Ho, Er and Tm), the 1.26–1.31 Å N–N distances do not follow any periodic trends, but the Raman stretching frequencies for Gd–Tm were found to decrease regularly with decreasing atomic number and increasing Lewis acidity of the metal. Similar correlations can be seen with the late metals in complexes of the other series, 1-Ln, 2-Ln and3-Ln, but exceptions exist, particularly for the larger metals. Comparisons between the several types of complexes as a function of ligand were more complicated and variations in stretching frequency as a function of L in the {[(Me3 Si)2 N]2 Y(L)}2 (μ–η 2 :η 2 -N2 ) substituted versions of4-Y did not give trends consistent with bond distances or Gutmann donor numbers.