6 research outputs found
Gallium Hydrides with a Radical-Anionic Ligand
The reaction of Cl<sub>2</sub>GaH with a sodium salt of the dpp-Bian radical-anion (dpp-Bian<sup>•–</sup>)Na (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene)
affords paramagnetic gallane (dpp-Bian<sup>•–</sup>)Ga(Cl)H
(<b>1</b>). Oxidation of (dpp-Bian<sup>2–</sup>)Ga–Ga(dpp-Bian<sup>2–</sup>) (<b>2</b>) with N<sub>2</sub>O results in
the dimeric oxide (dpp-Bian<sup>•–</sup>)Ga(μ<sup>2</sup>-O)<sub>2</sub>Ga(dpp-Bian<sup>•–</sup>) (<b>3</b>). A treatment of the oxide <b>3</b> with phenylsilane
affords paramagnetic gallium hydrides (dpp-Bian<sup>•–</sup>)GaH<sub>2</sub> (<b>4</b>) and (dpp-Bian<sup>•–</sup>)Ga{OSi(Ph)H<sub>2</sub>}H (<b>5</b>) depending on the reagent’s
stoichiometry. The reaction of digallane <b>2</b> with benzaldehyde
produces pinacolate (dpp-Bian<sup>•–</sup>)Ga(O<sub>2</sub>C<sub>2</sub>H<sub>2</sub>Ph<sub>2</sub>) (<b>6</b>).
In the presence of PhSiH<sub>3</sub>, the reaction between digallane <b>2</b> and benzaldehyde (<b>2</b>: PhSiH<sub>3</sub>: PhC(H)O
= 1:4:4) affords compound <b>4</b>. The newly prepared complexes <b>1</b>, <b>3</b>–<b>6</b> consist of a spin-labeled
diimine ligand–dpp-Bian radical-anion. The presence of the
ligand-localized unpaired electron allows the use of the ESR spectroscopy
for characterization of the gallium hydrides reported. The molecular
structures of compounds <b>1</b>, <b>3</b>–<b>6</b> have been determined by the single-crystal X-ray analysis
Mononuclear dpp-Bian Gallium Complexes: Synthesis, Crystal Structures, and Reactivity toward Alkynes and Enones
Treatment
of (dpp-Bian)Ga–Ga(dpp-Bian) (<b>1</b>)
(dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with
iodine gives (dpp-Bian)Ga(I)–Ga(I)(dpp-Bian) (<b>2</b>), which reacts in situ with K(C<sub>5</sub>H<sub>4</sub>CH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>) (KCp<sup>Do</sup>) or K(OCH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>) (KOR<sup>Do</sup>) to produce the
monomeric species (dpp-Bian)GaCp<sup>Do</sup> (<b>3</b>) and
(dpp-Bian)GaOR<sup>Do</sup> (<b>4</b>), respectively. Complex <b>3</b> reacts with PhCCH to give the paramagnetic derivative
(dpp-Bian)Ga(CCPh)<sub>2</sub> (<b>5</b>), while compound <b>4</b> is inert toward this alkyne. In contrast, monomeric (dpp-Bian)Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>6</b>) reacts with PhCCH
and HCCH to give the cycloaddition products [dpp-Bian(PhCCH)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>7</b>) and [dpp-Bian(HCCH)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>8</b>). The related compounds
[dpp-Bian(MeCCC(O)OMe)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>9</b>) and [dpp-Bian(CH<sub>2</sub>CHC(Me)O)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>10</b>) have been obtained in
the reactions of complex <b>6</b> with methyl 2-butynoate and
methyl vinyl ketone, respectively. New complexes have been characterized
by <sup>1</sup>H NMR (<b>3</b>, <b>4</b>, and <b>7</b>–<b>10</b>) and ESR (<b>5</b>) spectroscopy; their
molecular structures have been established by single-crystal X-ray
analysis. The catalytic activity of complex <b>6</b> in the
hydroamination and hydroarylation of alkynes has been examined
Mononuclear dpp-Bian Gallium Complexes: Synthesis, Crystal Structures, and Reactivity toward Alkynes and Enones
Treatment
of (dpp-Bian)Ga–Ga(dpp-Bian) (<b>1</b>)
(dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with
iodine gives (dpp-Bian)Ga(I)–Ga(I)(dpp-Bian) (<b>2</b>), which reacts in situ with K(C<sub>5</sub>H<sub>4</sub>CH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>) (KCp<sup>Do</sup>) or K(OCH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>) (KOR<sup>Do</sup>) to produce the
monomeric species (dpp-Bian)GaCp<sup>Do</sup> (<b>3</b>) and
(dpp-Bian)GaOR<sup>Do</sup> (<b>4</b>), respectively. Complex <b>3</b> reacts with PhCCH to give the paramagnetic derivative
(dpp-Bian)Ga(CCPh)<sub>2</sub> (<b>5</b>), while compound <b>4</b> is inert toward this alkyne. In contrast, monomeric (dpp-Bian)Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>6</b>) reacts with PhCCH
and HCCH to give the cycloaddition products [dpp-Bian(PhCCH)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>7</b>) and [dpp-Bian(HCCH)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>8</b>). The related compounds
[dpp-Bian(MeCCC(O)OMe)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>9</b>) and [dpp-Bian(CH<sub>2</sub>CHC(Me)O)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>10</b>) have been obtained in
the reactions of complex <b>6</b> with methyl 2-butynoate and
methyl vinyl ketone, respectively. New complexes have been characterized
by <sup>1</sup>H NMR (<b>3</b>, <b>4</b>, and <b>7</b>–<b>10</b>) and ESR (<b>5</b>) spectroscopy; their
molecular structures have been established by single-crystal X-ray
analysis. The catalytic activity of complex <b>6</b> in the
hydroamination and hydroarylation of alkynes has been examined
Mononuclear dpp-Bian Gallium Complexes: Synthesis, Crystal Structures, and Reactivity toward Alkynes and Enones
Treatment
of (dpp-Bian)Ga–Ga(dpp-Bian) (<b>1</b>)
(dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with
iodine gives (dpp-Bian)Ga(I)–Ga(I)(dpp-Bian) (<b>2</b>), which reacts in situ with K(C<sub>5</sub>H<sub>4</sub>CH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>) (KCp<sup>Do</sup>) or K(OCH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>) (KOR<sup>Do</sup>) to produce the
monomeric species (dpp-Bian)GaCp<sup>Do</sup> (<b>3</b>) and
(dpp-Bian)GaOR<sup>Do</sup> (<b>4</b>), respectively. Complex <b>3</b> reacts with PhCCH to give the paramagnetic derivative
(dpp-Bian)Ga(CCPh)<sub>2</sub> (<b>5</b>), while compound <b>4</b> is inert toward this alkyne. In contrast, monomeric (dpp-Bian)Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>6</b>) reacts with PhCCH
and HCCH to give the cycloaddition products [dpp-Bian(PhCCH)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>7</b>) and [dpp-Bian(HCCH)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>8</b>). The related compounds
[dpp-Bian(MeCCC(O)OMe)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>9</b>) and [dpp-Bian(CH<sub>2</sub>CHC(Me)O)]Ga(S<sub>2</sub>CNMe<sub>2</sub>) (<b>10</b>) have been obtained in
the reactions of complex <b>6</b> with methyl 2-butynoate and
methyl vinyl ketone, respectively. New complexes have been characterized
by <sup>1</sup>H NMR (<b>3</b>, <b>4</b>, and <b>7</b>–<b>10</b>) and ESR (<b>5</b>) spectroscopy; their
molecular structures have been established by single-crystal X-ray
analysis. The catalytic activity of complex <b>6</b> in the
hydroamination and hydroarylation of alkynes has been examined
Digallane with Redox-Active Diimine Ligand: Dualism of Electron-Transfer Reactions
The reactivity of digallane (dpp-Bian)Ga–Ga(dpp-Bian)
(<b>1</b>), which consists of redox-active ligand 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene
(dpp-Bian), has been studied. The reaction of <b>1</b> with
I<sub>2</sub> proceeds via one-electron oxidation of each of two dpp-Bian
ligands to a radical-anionic state and affords complex (dpp-Bian)IGa–GaI(dpp-Bian)
(<b>2</b>). Dissolution of complex <b>2</b> in pyridine
(Py) gives monomeric compound (dpp-Bian)GaI(Py) (<b>3</b>) as
a result of a solvent-induced intramolecular electron transfer from
the metal–metal bond to the dpp-Bian ligands. Treatment of
compound <b>3</b> with B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> leads to removal of pyridine and restores compound <b>2</b>. The reaction of compound <b>1</b> with 3,6-di-<i>tert</i>-butyl-<i>ortho</i>-benzoquinone (3,6-Q) proceeds with
oxidation of all the redox-active centers in <b>1</b> (the Ga–Ga
bond and two dpp-Bian dianions) and results in mononuclear catecholate
(dpp-Bian)Ga(Cat) (<b>4</b>) (Cat = [3,6-Q]<sup>2–</sup>). Treatment of <b>4</b> with AgBF<sub>4</sub> gives a mixture
of [(dpp-Bian)<sub>2</sub>Ag][BF<sub>4</sub>] (<b>5</b>) and
(dpp-Bian)GaF(Cat) (<b>6</b>), which both consist of neutral
dpp-Bian ligands. The reduction of benzylideneacetone (BA) with <b>1</b> generates the BA radical-anions, which dimerize, affording
(dpp-Bian)Ga–(BA–BA)–Ga(dpp-Bian) (<b>7</b>). In this case the Ga–Ga bond remains unchanged. Within 10
min at 95 °C in solution compound <b>7</b> undergoes transformation
to paramagnetic complex (dpp-Bian)Ga(BA–BA) (<b>8</b>) and metal-free compound C<sub>36</sub>H<sub>40</sub>N<sub>2</sub> (<b>9</b>). The latter is a product of intramolecular addition
of the C–H bond of one of the <i>i</i>Pr groups to
the CN bond in dpp-Bian. Diamagnetic compounds <b>3</b>, <b>5</b>, <b>6</b>, and <b>9</b> have been characterized
by NMR spectroscopy, and paramagnetic complexes <b>2</b>, <b>4</b>, <b>7</b>, and <b>8</b> by ESR spectroscopy.
Molecular structures of <b>2</b>–<b>7</b> and <b>9</b> have been established by single-crystal X-ray analysis