Title: End-On Bridging Dinitrogen Complex of Scandium

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 NMR spectroscopy and 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 SO³⁺ 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 bindingmore » in this scandium system.« less

Authors:

Woen, David H.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5764-1453"

Chen, Guo P.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-4743-4450"

Ziller, Joseph W. ^[1]; Boyle, Timothy J.  ^[2];

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Furche, Filipp  ^[1];

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Evans, William J.  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-0651-418X"

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+ Show Author Affiliations

1. Univ. of California, Irvine, CA (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Publication Date:

Thu Sep 28 00:00:00 EDT 2017

Research Org.:

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1473943

Report Number(s):

SAND-2018-10055J
Journal ID: ISSN 0002-7863; 667860

Grant/Contract Number:  

AC04-94AL85000

Resource Type:

Accepted Manuscript

Journal Name:

Journal of the American Chemical Society

Additional Journal Information:

Journal Volume: 139; Journal Issue: 42; Journal ID: ISSN 0002-7863

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY