Condensation of Ammonium Niobium Oxalate Studied by NMR Crystallography and X-ray Powder Diffraction | Sciact - CRIS-система Института катализа

Condensation of Ammonium Niobium Oxalate Studied by NMR Crystallography and X-ray Powder Diffraction Научная публикация

Журнал

Catalysis Today
ISSN: 0920-5861 , E-ISSN: 1873-4308

Вых. Данные

Год: 2020, Том: 354, Страницы: 26-35 Страниц : 10 DOI: 10.1016/j.cattod.2019.01.072

Ключевые слова

Niobium (V) oxalate; Crystal structure transformation; Solid-state NMR; X-ray powder diffraction; Simultaneous thermal analysis; DFT calculations

Авторы

Papulovskiy Evgeniy ¹ , Kirik Sergei D. ² , Khabibulin Dzhalil F. ^1,3 , Shubin Aleksandr A. ^1,3 , Bondareva Valentina M. ¹ , Samoilo Aleksandr S. ² , Lapina Olga B. ^1,3

Организации

1	Boreskov Institute of Catalysis, pr. Lavrentieva 5, 630090, Novosibirsk, Russia
2	Siberian Federal University, pr. Svobodny 79, 660041, Krasnoyarsk, Russia
3	Novosibirsk State University, Pirogova 2, 630090, Novosibirsk, Russia

Информация о финансировании (2)

1	Российский фонд фундаментальных исследований	17-03-00531
2	Министерство образования и науки Российской Федерации	1025

Unusual structure transformation in NH4[NbO(C2O4)2(H2O)2]∙nH2O was discovered and investigated by combination of techniques including NMR crystallography (variable temperature 1H, 2H, 13C and 93Nb solid-state NMR methods), X-Ray powder diffraction, simultaneous thermal analysis and DFT calculations. It has been revealed that the mixture of known oxalate phases NH4[NbO(C2O4)2(H2O)2]∙3H2O (Phase I) and NH4[NbO(C2O4)2(H2O)2]·2H2O (Phase II) treated at mild condition (temperature up to 100 °C in vacuo) induces an unknown crystal phase, catena-NH4[NbO2/2(C2O4)2(H2O)] (Phase III). The new orthorhombic phase has polymeric structure consisted of 7-coordinated niobium fragments [NbO2/2(C2O4)2(H2O)] connected by oxygen bridges (NbONb) forming the infinite zigzag chains along the axis. The bridging oxygen atoms are connected to Nb symmetrically with respect to the 2-fold axis. Each of them forms two identical bonds Nb-O of 1.892(6) Å length, indicating their origination from the condensation process. The niobium coordination polyhedron can be crossed by the plane passing through the Nb, (O)2/2, (H2O) atoms. The oxalate groups lie in the opposite sides from the plane. In the new phase, 93Nb has unusually small nuclear quadrupole coupling constant mainly due to the developed thermal mobility of the crystal lattice. Variable temperature 93Nb, 2H and 13C NMR experiments together with DFT calculations confirm that the new Phase III has proton and ligand mobility. This mobility of the lattice correlates with the fact that hydrogen bonds network stabilizing the structure of Phases I and II practically disappear in the new Phase III.

Papulovskiy E. , Kirik S.D. , Khabibulin D.F. , Shubin A.A. , Bondareva V.M. , Samoilo A.S. , Lapina O.B.
Condensation of Ammonium Niobium Oxalate Studied by NMR Crystallography and X-ray Powder Diffraction
Catalysis Today. 2020. V.354. P.26-35. DOI: 10.1016/j.cattod.2019.01.072 WOS Scopus РИНЦ CAPlus OpenAlex

Поступила в редакцию:	8 авг. 2018 г.
Принята к публикации:	26 янв. 2019 г.
Опубликована online:	30 янв. 2019 г.
Опубликована в печати:	1 сент. 2020 г.

Web of science:	WOS:000544088500004
Scopus:	2-s2.0-85061108373
РИНЦ:	38668015
Chemical Abstracts:	2019:263052
OpenAlex:	W2914764371

БД	Цитирований
Scopus	4
РИНЦ	3
Web of science	4
OpenAlex	5