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Ion-Size-Dependent Formation of Mixed Titanium/Lanthanide Oxo Clusters.

Artner C, Kronister S, Czakler M, Schubert U - Eur J Inorg Chem (2014)

Bottom Line: The mixed-metal oxo clusters LnTi4O3(OiPr)2(OMc)11 (Ln = La, Ce; OMc = methacrylate), Ln2Ti6O6(OMc)18(HOiPr) (Ln = La, Ce, Nd, Sm) and Ln2Ti4O4(OMc)14(HOMc)2 (Ln = Sm, Eu, Gd, Ho) have been synthesized from titanium isopropoxide, the corresponding lanthanide acetate and methacrylic acid.The type of cluster obtained strongly depends on the size of the lanthanide ion.

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ABSTRACT

The mixed-metal oxo clusters LnTi4O3(OiPr)2(OMc)11 (Ln = La, Ce; OMc = methacrylate), Ln2Ti6O6(OMc)18(HOiPr) (Ln = La, Ce, Nd, Sm) and Ln2Ti4O4(OMc)14(HOMc)2 (Ln = Sm, Eu, Gd, Ho) have been synthesized from titanium isopropoxide, the corresponding lanthanide acetate and methacrylic acid. The type of cluster obtained strongly depends on the size of the lanthanide ion.

No MeSH data available.


η1-Carboxylate ligand stabilized by a coordinated RCOOH (left, as in Ln2Ti4) or R′OH molecule (right, as in Ln2Ti6).
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fig04: η1-Carboxylate ligand stabilized by a coordinated RCOOH (left, as in Ln2Ti4) or R′OH molecule (right, as in Ln2Ti6).

Mentions: In the case of Ln2Ti4, the total metal charge is +22, and the number of coordination sites is 40, assuming six-coordinate Ti atoms and eight-coordinate Ln atoms. Thus, 14 monoanionic ligands are necessary to balance the charges of the Ln2Ti4O4 core, and 28 coordination sites must still be occupied. This requirement would be met if all OMc ligands in Ln2Ti4 were bidentate. Apparently this is not possible for steric reasons, and two OMc ligands coordinate only in an η1 manner; to occupy all the available coordination sites two neutral McOH ligands are additionally coordinated to the same Ti atom (Ti2). Both interact with each other through a strong hydrogen bond [O16···O18 2.454(8) Å in Eu2Ti4]. Because the Ti2–O15 distance is significantly longer than that of Ti2–O17 [Ti2–O15 2.140(2), Ti2–O17 1.974(3) Å], it is likely that the hydrogen atom is closer to O16. We pointed out earlier that the combination of an η1 and a neutral proton-donating ligand connected through a hydrogen bond (Scheme 1) is structurally equivalent to a monoanionic bidentate ligand.11 Due to the octahedral coordination of Ti, chelating carboxylate ligands are extremely rare. Such coordination would cause too large a distortion of the Ti coordination sphere.


Ion-Size-Dependent Formation of Mixed Titanium/Lanthanide Oxo Clusters.

Artner C, Kronister S, Czakler M, Schubert U - Eur J Inorg Chem (2014)

η1-Carboxylate ligand stabilized by a coordinated RCOOH (left, as in Ln2Ti4) or R′OH molecule (right, as in Ln2Ti6).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384754&req=5

fig04: η1-Carboxylate ligand stabilized by a coordinated RCOOH (left, as in Ln2Ti4) or R′OH molecule (right, as in Ln2Ti6).
Mentions: In the case of Ln2Ti4, the total metal charge is +22, and the number of coordination sites is 40, assuming six-coordinate Ti atoms and eight-coordinate Ln atoms. Thus, 14 monoanionic ligands are necessary to balance the charges of the Ln2Ti4O4 core, and 28 coordination sites must still be occupied. This requirement would be met if all OMc ligands in Ln2Ti4 were bidentate. Apparently this is not possible for steric reasons, and two OMc ligands coordinate only in an η1 manner; to occupy all the available coordination sites two neutral McOH ligands are additionally coordinated to the same Ti atom (Ti2). Both interact with each other through a strong hydrogen bond [O16···O18 2.454(8) Å in Eu2Ti4]. Because the Ti2–O15 distance is significantly longer than that of Ti2–O17 [Ti2–O15 2.140(2), Ti2–O17 1.974(3) Å], it is likely that the hydrogen atom is closer to O16. We pointed out earlier that the combination of an η1 and a neutral proton-donating ligand connected through a hydrogen bond (Scheme 1) is structurally equivalent to a monoanionic bidentate ligand.11 Due to the octahedral coordination of Ti, chelating carboxylate ligands are extremely rare. Such coordination would cause too large a distortion of the Ti coordination sphere.

Bottom Line: The mixed-metal oxo clusters LnTi4O3(OiPr)2(OMc)11 (Ln = La, Ce; OMc = methacrylate), Ln2Ti6O6(OMc)18(HOiPr) (Ln = La, Ce, Nd, Sm) and Ln2Ti4O4(OMc)14(HOMc)2 (Ln = Sm, Eu, Gd, Ho) have been synthesized from titanium isopropoxide, the corresponding lanthanide acetate and methacrylic acid.The type of cluster obtained strongly depends on the size of the lanthanide ion.

View Article: PubMed Central - PubMed

ABSTRACT

The mixed-metal oxo clusters LnTi4O3(OiPr)2(OMc)11 (Ln = La, Ce; OMc = methacrylate), Ln2Ti6O6(OMc)18(HOiPr) (Ln = La, Ce, Nd, Sm) and Ln2Ti4O4(OMc)14(HOMc)2 (Ln = Sm, Eu, Gd, Ho) have been synthesized from titanium isopropoxide, the corresponding lanthanide acetate and methacrylic acid. The type of cluster obtained strongly depends on the size of the lanthanide ion.

No MeSH data available.