TY - JOUR
T1 - First synthesis and structural determination of a monomeric, unsolvated lithium amide, LiNH2
AU - Grotjahn, D. B.
AU - Sheridan, P. M.
AU - Al Jihad, I.
AU - Ziurys, L. M.
PY - 2001
Y1 - 2001
N2 - Alkali metal amides typically aggregate in solution and the solid phase, and even in the gas phase. In addition, even in the few known monomeric structures, the coordination number of the alkali metal is raised by binding of Lewis-basic solvent molecules, with concomitant change in structure. In contrast, the simplest lithium amide LiNH2 has never been made in a monomeric form, even though its structure has been theoretically predicted several times. Here, the first experimental structural data for a monomeric, unsolvated lithium amide are determined using a combination of gas-phase synthesis and millimeter/submillimeter-wave spectroscopy. All data point to a planar structure for LiNH2. The ro structure of LiNH2 has a Li-N distance of 1.736(3) Å, an N-H distance of 1.022(3) Å, and a H-N-H angle of 106.9(1)°. These results are compared with theoretical predictions for LiNH2, and experimental data for oligomeric, solid-phase samples, which could not resolve the question of whether LiNH2 is planar or not. In addition, comparisons are made with revised gas-phase and solid-phase data and calculated structures of NaNH2.
AB - Alkali metal amides typically aggregate in solution and the solid phase, and even in the gas phase. In addition, even in the few known monomeric structures, the coordination number of the alkali metal is raised by binding of Lewis-basic solvent molecules, with concomitant change in structure. In contrast, the simplest lithium amide LiNH2 has never been made in a monomeric form, even though its structure has been theoretically predicted several times. Here, the first experimental structural data for a monomeric, unsolvated lithium amide are determined using a combination of gas-phase synthesis and millimeter/submillimeter-wave spectroscopy. All data point to a planar structure for LiNH2. The ro structure of LiNH2 has a Li-N distance of 1.736(3) Å, an N-H distance of 1.022(3) Å, and a H-N-H angle of 106.9(1)°. These results are compared with theoretical predictions for LiNH2, and experimental data for oligomeric, solid-phase samples, which could not resolve the question of whether LiNH2 is planar or not. In addition, comparisons are made with revised gas-phase and solid-phase data and calculated structures of NaNH2.
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U2 - 10.1021/ja003422h
DO - 10.1021/ja003422h
M3 - Article
C2 - 11389631
AN - SCOPUS:0034820023
SN - 0002-7863
VL - 123
SP - 5489
EP - 5494
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 23
ER -