On the influence of the titanium source on the composition and structure of novel titanoniobates

Abstract

Systematic variation of the titanium source and the reaction temperature applied during hydrothermal synthesis led to crystallization of four new titanoniobates: {[Ni(cyclam)]4[Ti2Nb8O28]}n·∼28nH2O (I), K[Ni(cyclam)]3[TiNb9O28]·xH2O; x = 18 (II), x = 14 (III) and x ∼ 10(IV).

Capturing the Heptaniobate {Nb7O22}9– Anion by Covalent Bond Formation: Synthesis, Crystal Structure, and Selected Properties of {[Fe(cyclam)]3Nb7O22}· ≈ 19 H2O

“…Caused by the coordination mode, the cyclam molecule is strongly distorted so that two N and O atoms are in trans position with N–Fe–O angles of 175.8(4) and 177.4(4)° (Table S3, Figure ). In most cases, the cyclam ligand is coordinated in planar mode but here one of the CH 2 –CH 2 –CH 2 –N–CH 2 –CH 2 fragments is rotated by about 90° (Figure ) . This kind of coordination was already reported for this ligand in some Fe centered complexes .…”

“…In most cases, the cyclam ligand is coordinated in planar mode but here one of the CH 2 -CH 2 -CH 2 -N-CH 2 -CH 2 fragments is rotated by about 90° (Figure 3). [2] This kind of coordination was already reported for this ligand in some Fe centered complexes. [21][22][23] The Fe-O bond length are between 1.873(6) and 1.945(6) Å and the Fe-N bonds are at 2.13(3)-2.224(14) Å.…”

“…[7] An even larger cluster with the composition {Nb 24 [11] [Cu(en) 2 ] 3 [14] which always contain a K + cation located in the middle of the ring (Figure 1b). It is also possible to incorporate ethylene diammonium cations (H 2 en 2+ ) inside the ring as exemplified in (H 2 en) 1 [11] or (H 2 en) 6 [Cu(en) 2 [14] A further expansion is observed in the {Nb 32 Figure 1c). Inside the tetrameric moiety no guests are located due to the limited void ARTICLE space.…”

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

“…43,349,[353][354][355][356][357][358][359] A number of other transition metalbased polyoxometalates have been investigated, such as silver-containing polyoxometalates, 226,[360][361][362][363][364][365] zinccontaining polyoxometalates. 366 polyoxotantalate, [367][368][369][370][371][372][373][374][375][376][377][378][379][380][381][382][383][384] ruthenium-containing polyoxometalates, [385][386][387] coppercontaining polyoxometalates, [388][389][390] chromium-containing polyoxometalates, 391 and polyoxoaurates [392][393][394][395] ; their real applications to substitute their metal oxides counterparts deserve further exploration.…”

“…A number of other transition metal‐based polyoxometalates have been investigated, such as silver‐containing polyoxometalates, zinc‐containing polyoxometalates . polyoxotantalate, ruthenium‐containing polyoxometalates, copper‐containing polyoxometalates, chromium‐containing polyoxometalates, and polyoxoaurates; their real applications to substitute their metal oxides counterparts deserve further exploration.…”