Carbon-Rich Ruthenium Allenylidene Complexes Bearing
Heteroscorpionate Ligands
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Abstract
A series of ruthenium allenylidene
complexes bearing polyaromatic
substituents have been prepared starting from [Ru(bdmpza)Cl(PPh<sub>3</sub>)<sub>2</sub>] (<b>1</b>) (bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetato).
Reacting <b>1</b> with 1,1-bis(3,5-di-<i>tert</i>-butylphenyl)-1-methoxy-2-propyne
results in the formation of two structural isomers of an allenylidene
complex [Ru(bdmpza)Cl(CCC(Ph<sup><i>t</i></sup>Bu<sub>2</sub>)<sub>2</sub>)(PPh<sub>3</sub>)] (<b>5A</b>/<b>5B</b>), as well as the related carbonyl
complex [Ru(bdmpza)Cl(CO)(PPh<sub>3</sub>)] (<b>4A</b>/<b>4B</b>). Conversion of 9-ethynyl-9-fluorenol leads to the
corresponding allenylidene complex [Ru(bdmpza)Cl(CC(FN))(PPh<sub>3</sub>)] (<b>7A</b>/<b>7B</b>) (FN = fluorenyl). Based
on anthraquinone, a new synthetic route toward 10-ethynyl-10-hydroxyanthracen-9-one
via the trimethylsilyl-protected propargyl alcohol is described, and
subsequent conversion of this compound to the allenylidene complex
([Ru(bdmpza)Cl(CC(AO))(PPh<sub>3</sub>)] (<b>12A</b>/<b>12B</b>) (AO = anthrone) is
reported. The synthetic route from 7<i>H</i>-benzo[<i>no</i>]tetraphen-7-one to the propargyl alcohol 7-ethynyl-7<i>H</i>-benzo[<i>no</i>]tetraphen-7-ol is described,
which is followed by the transformation into the allenylidene complex
[Ru(bdmpza)Cl(CC(BT))(PPh<sub>3</sub>)] (<b>17A</b>/<b>17B</b>) (BT = benzotetraphene).
The molecular structures of <b>4B</b>, <b>7A</b>, <b>7B</b>, <b>12A</b>, <b>12B</b>, <b>13A</b>,
and <b>17A</b> have been characterized by single-crystal X-ray
crystallography, and these analyses suggest that <b>17A</b> might
function as a “metal-tuned organic field effect transistor”.
The electrochemical properties of the allenylidene complexes have
been studied via cyclic voltammetry, and time-dependent DFT calculations
have been conducted to assign weak absorptions in the NIR region to
forbidden MLCT transitions
