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

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.

Keywords: Carboxylate ligands; Cluster compounds; Lanthan­ides; Titanium.

Figure 1

Molecular structure of Eu₂Ti₄(μ₃-O)₄(μ₂-OMc)₁₂(η¹-OMc)₂(η¹-HOMc)₂ (Eu2Ti4). Hydrogen atoms have been omitted for clarity. Blue dashed lines indicate hydrogen bonds. Selected bond lengths [Å] and angles [°]: Eu1–O1 2.319(3), Eu1–O1′ 2.457(4), Eu1–O2 2.491(3), Eu1–O3 2.368(3), Eu1–O5 2.464(3), Eu1–O7 2.330(4), Eu1–O9 2.341(4), Eu1–O11 2.382(4), Ti1–O1 1.718(2), Ti1–O2 2.022(2), Ti1–O4 2.019(2), Ti1–O6 1.958(2), Ti1–O8 1.992(2), Ti1–O13 2.128(2), Ti2–O2 1.730(2), Ti2–O10 1.987(3), Ti2–O12 1.981(3), Ti2–O14 1.991(3), Ti2–O15 2.140(2), Ti2–O17 1.974(3); Eu1–O1–Eu1′ 111.06(11), Eu1–O1–Ti1 108.87(12), Eu1–O1–Ti1′ 133.59(12), Eu1–O2–Ti1 93.46(10), Eu1–O2–Ti2 126.19(12), Ti1–O2–Ti2 137.75(12).

Scheme 1

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

Figure 2

Molecular structure of La₂Ti₆(μ₃-O)₆(μ₂-OMc)₁₈(HOiPr)₂ (La2Ti6). Hydrogen have been omitted for clarity. Blue dashelines indicate hydrogen bonds. Selected bond lengths [Å] and angles [°]: La1–O1 2.538(3), La1–O1′ 2.552(3), La1–O2 2.526(3), La1–O3 3.045(3), La1–O4 2.447(4), La1–O6 2.482(4), La1–O8 2.496(4), La1–O10 2.545(4), La1–O12 2.458(4), Ti1–O1 1.705(3), Ti1–O2 1.987(3), Ti1–O5 2.004(3), Ti1–O7 1.977(3), Ti1–O9 1.990(3), Ti1–O14 2.185(3), Ti2–O2 1.743(3), Ti2–O3 1.976(3), Ti2–O11 1.954(3), Ti2–O15 1.974(3), Ti2–O16 2.023(3), Ti2–O18 2.101(3), Ti3–O3 1.742(3), Ti3–O13 1.944(4), Ti3–O17 2.010(4), Ti3–O19 2.011(4), Ti3–O20 1.924(4), Ti3–O22 2.158(4); La1–O1–La1 112.93(12), La1–O1–Ti1 107.50(14), La1–O1–Ti1′ 131.54(15), La1–O2–Ti1 99.27(12), La1–O2–Ti2 116.61(15), Ti1–O2–Ti2 142.62(17), La1–O3–Ti2 90.89(11), La1–O3–Ti3 130.38(16), Ti2–O3–Ti3 130.7(2).

Figure 3

Molecular structure of LaTi₄(μ₃-O)₃(OiPr)₂(μ₂-OMc)₁₁ (LaTi4) Hydrogen atoms are omitted or clarity. Selected bond lengths [Å] and angles [°]: La1–O1 2.6410(18), La1–O2 2.4793(17), La1–O3 2.6228(18), La1–O4 2.5455(18), La1–O6 2.447(2), La1–O8 2.5447(19), La1–O10 2.558(2), La1–O12 2.533(2), La1–O14 2.548(2), Ti1–O1 1.9688(18), Ti1–O5 1.927(2), Ti1–O7 1.977(2), Ti1–O16 2.038(2), Ti1–O18 2.051(2), Ti1–O26 1.782(2), Ti2–O1 1.7904(18), Ti2–O2 1.8249(18), Ti2–O9 1.981(2), Ti2–O17 2.056(2), Ti2–O19 2.019(2), Ti2–O20 2.0826(19), Ti3–O2 1.8409(18), Ti3–O3 1.7786(18), Ti3–O11 1.975(2), Ti3–O21 2.084(2), Ti3–O22 2.041(2), Ti3–O24 2.035(2), Ti4–O3 1.9702(19), Ti4–O13 1.925(2), Ti4–O15 1.938(2), Ti4–O23 2.029(2), Ti4–O25 2.046(2), Ti4–O27 1.774(2); O1–La1–O2 60.33(6), O2–La1–O3 60.40(6)°, La1–O1–Ti1 126.53(8), La1–O1–Ti2 100.45(7), Ti1–O1–Ti2 132.00(10), La1–O2–Ti2 105.50(7), La1–O2–Ti3 105.34(8), Ti2–O2–Ti3 149.13(10), La1–O3–Ti3 101.80(8), La1–O3–Ti4 123.24(8), Ti3–O3–Ti4 132.39(10).