Synthesis,
Structure, and Reactivity of Lanthanide
Complexes Incorporating Indolyl Ligands in Novel Hapticities
- Publication date
- Publisher
Abstract
The
chemistry of interactions of 2-(2,6-diisopropylphenylaminomethylene)indole
ligand (<b>1</b>) with europium and ytterbium amides is described.
Reaction of 2-(2,6-diisopropylphenylaminomethylene)indole 2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NHCH<sub>2</sub>)C<sub>8</sub>H<sub>5</sub>NH (<b>1</b>) with europium amide
[(Me<sub>3</sub>Si)<sub>2</sub>N]<sub>3</sub>Eu<sup>III</sup>(μ-Cl)Li(THF)<sub>3</sub> afforded a novel europium(II) complex formulated as {[μ-η<sup>6</sup>:η<sup>1</sup>:η<sup>1</sup>-2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NCH)C<sub>8</sub>H<sub>5</sub>N]Eu[2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NCH)C<sub>8</sub>H<sub>5</sub>N]}<sub>2</sub> (<b>2</b>), having a bridged indolyl ligand in the novel μ-η<sup>6</sup>:η<sup>1</sup>:η<sup>1</sup> hapticities with
the reduction of europium(III) to europium(II) and the oxidation of
amino to imino group. Reaction of 2-(2,6-diisopropylphenylaminomethylene)indole
2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NHCH<sub>2</sub>)C<sub>8</sub>H<sub>5</sub>NH (<b>1</b>) with
ytterbium(III) amide [(Me<sub>3</sub>Si)<sub>2</sub>N]<sub>3</sub>Yb<sup>III</sup>(μ-Cl)Li(THF)<sub>3</sub> produced the only
deprotonated ytterbium(III) complex formulated as [2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NCH<sub>2</sub>)C<sub>8</sub>H<sub>5</sub>N]Yb[N(SiMe<sub>3</sub>)<sub>2</sub>](THF)<sub>2</sub> (<b>3</b>), having an η<sup>1</sup> hapticity
indolyl ligand. Reaction of <b>2</b> with formamidine [(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)NCHNH(C<sub>6</sub>H<sub>3</sub>Me<sub>2</sub>-2,6)] produced {[μ-η<sup>3</sup>:η<sup>1</sup>:η<sup>1</sup>-2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NCH)C<sub>8</sub>H<sub>5</sub>N]Eu[(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)NCHN(C<sub>6</sub>H<sub>3</sub>Me<sub>2</sub>-2,6)](THF)}<sub>2</sub> (<b>4</b>), which has
a bridged indolyl ligand in the novel μ-η<sup>3</sup>:η<sup>1</sup>:η<sup>1</sup> hapticities, whereas the reaction of <b>2</b> with the more sterically bulky formamidine [(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)NCHNH(C<sub>6</sub>H<sub>3</sub><i>i</i>-Pr<sub>2</sub>-2,6)] afforded complex
{[μ-η<sup>2</sup>:η<sup>1</sup>:η<sup>1</sup>-2-(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>NCH)C<sub>8</sub>H<sub>5</sub>N]Eu[(2,6-<i>i</i>-Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)NCHN(C<sub>6</sub>H<sub>3</sub><i>i</i>-Pr<sub>2</sub>-2,6)](THF)}<sub>2</sub> (<b>5</b>), having the indolyl ligand in the novel μ-η<sup>2</sup>:η<sup>1</sup>:η<sup>1</sup> hapticities. The
results represent the first example of organometallic complexes having
indolyl ligands in the novel μ-η<sup>6</sup>:η<sup>1</sup>:η<sup>1</sup>, μ-η<sup>3</sup>:η<sup>1</sup>:η<sup>1</sup>, and μ-η<sup>2</sup>:η<sup>1</sup>:η<sup>1</sup> bonding modes with metal
