New Volatile Tantalum Imido Precursors with Carboxamide Ligands

• Published in: ACS omega Vol. 6; no. 38; pp. 24795 - 24802
• Main Authors: Hwang, Jeong Min, Lee, Sung Kwang, Shin, Sunyoung, Jeong, Ji-Seoung, Kim, Hae Sun, Ryu, Ji Yeon, Eom, Taeyong, Park, Bo Keun, Kim, Chang Gyoun, Chung, Taek-Mo
• Format: Journal Article
• Language: English
• Published: American Chemical Society 28.09.2021
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.1c03659

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.