Naslov
A series of compounds containing various (oxalato)tantalate(V) complex anions – synthesis, properties and the mixed-metal oxide formation via thermal decomposition

Autori
Androš, Lidija ; Matković-Čalogović, Dubravka ; Planinić, Pavica

Izvornik
Crystengcomm (1466-8033) 15 (2013); 533-543

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
(oxalato)tantalate(V) complex anions; crystal structures; NiTa2O6

Sažetak
Four new heterometallic complexes, [Hphen][Ni(phen)3][Ta(C2O4)4]x6.5H2O (1), [Ni(phen)3][Ta(OH)(C2O4)3]x8H2O (2), [Ni(phen)3][Ta(OC2H5)(C2O4)3]xH2O (3) and [Ni(phen)3][Ta(OCH3)(C2O4)3]xH2O (4) (phen = 1, 10-phenanthroline) were obtained by using an (oxalato)tantalate(V) solution as a source of complex anions. Crystal structures of all four compounds were solved. The complexes contain the same [Ni(phen)3]2+ cation but different (oxalato)tantalate(V) complex anions. The nickel(II) atom in the cation is coordinated with six nitrogen atoms in a trigonally distorted octahedral environment. The coordination sphere around the tantalum atom is subject to change due to the solvent change. In the complex anion of 1 the tantalum(V) atom is octacoordinated by eight oxygen atoms from the four oxalate groups, whereas in the anions of 2, 3 and 4 the coordination polyhedron around tantalum is a distorted pentagonal bipyramid comprising six oxygen atoms from the three oxalate groups and another oxygen atom from the additional oxygen ligand. Different complex anions in 1-4 give rise to the variability of structural architectures. Crystallization water molecules and the (oxalato)tantalate(V) anions direct diverse hydrogen bonding patterns: from one-dimensional hydrogen-bonded chains in 3 and 4, to an extended three-dimensional framework in 2. Compound 1 contains two different cations, [Hphen]+ and [Ni(phen)3]2+ that are involved in a two-dimensional stacking arrangement. The compounds were studied also by the TG/DTA analysis, and the composition of oxides as the final decomposition products was checked by the powder X-ray diffraction method. The results indicate that the new compounds are prospective and applicable Ni–Ta precursors for the synthesis of nickel tantalate, NiTa2O6.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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