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. 2021 Sep 16;6(38):24795-24802.
doi: 10.1021/acsomega.1c03659. eCollection 2021 Sep 28.

New Volatile Tantalum Imido Precursors with Carboxamide Ligands

Jeong Min Hwang  1 , Sung Kwang Lee  1   2 , Sunyoung Shin  1 , Ji-Seoung Jeong  1   2 , Hae Sun Kim  1   2 , Ji Yeon Ryu  1 , Taeyong Eom  1 , Bo Keun Park  1 , Chang Gyoun Kim  1 , Taek-Mo Chung  1
Affiliations

New Volatile Tantalum Imido Precursors with Carboxamide Ligands

Jeong Min Hwang et al. ACS Omega. .

Abstract

A series of Ta(V) t Bu-imido/N-alkoxy carboxamide complexes, TaCl2(N t Bu)(pyridine)(edpa) (1), TaCl(N t Bu)(edpa)2 (2), Ta(N t Bu)(edpa)3 (3), TaCl2(N t Bu)(pyridine)(mdpa) (4), and Ta(N t Bu)(mdpa)3 (5), were successfully synthesized by metathesis reactions between Ta(N t Bu)Cl3(py)2 and several equivalents of Na(edpa) (edpaH = N-ethoxy-2,2-dimethylpropanamide) and Na(mdpa) (mdpaH = N-methoxy-2,2-dimethylpropanamide). Furthermore, complexes 3 and 5 were simply transformed to new dimeric structures [Ta(μ2-O)(edpa)3]2 (6) and [Ta(μ2-O)(mdpa)3]2 (7) with the elimination of the N t Bu imido group by air exposure. Compounds 1-7 were characterized by 1H and 13C nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis revealed that complexes 3 and 5 have a distorted pentagonal bipyramidal geometry around the central Ta atom, with three monoanionic bidentate N-alkoxy carboxamide ligands and one t Bu imido ligand saturating the coordination of tantalum ions. TGA revealed that complexes 3 and 5 had superior thermal characteristics and stability. These complexes could potentially be applied as precursors for tantalum oxide thin films.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Scheme 1
Scheme 1. Synthesis of Complexes 1–5
Figure 1
Figure 1
Crystal structure of Ta(NtBu)(edpa)3 (3) without disorder. H atoms are omitted for clarity. Color code: Ta, green; N, blue; O, red; and C, gray.
Figure 2
Figure 2
Crystal structure of Ta(NtBu)(mdpa)3 (5). H atoms are omitted for clarity. Color code: Ta, green; N, blue; O, red; and C, gray.
Figure 3
Figure 3
Crystal structure of [Ta(μ2–O)(edpa)3]2. H atoms are omitted for clarity. Color code: Ta, green; N, blue; O, red; and C, gray.
Scheme 2
Scheme 2. Synthesis of Complexes 6 and 7
Figure 4
Figure 4
TGA trace of complexes 1–7 under N2.
See this image and copyright information in PMC

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