Synthesis and Structures
of Cuprous Triptycylthiolate
Complexes
- Publication date
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Abstract
A synthesis of 1-(thioacetyl)triptycene (<b>5</b>), a convenient
protected form of 1-(thiolato)triptycene [STrip]<sup>−</sup>, is described, a key transformation being the high yield conversion
of <i>tert</i>-butyl 1-triptycenyl sulfide (<b>8</b>) to <b>5</b> by a protocol employing BBr<sub>3</sub>/AcCl.
Syntheses of the two-coordinate copper(I) compounds [Bu<sub>4</sub>N][Cu(STrip)<sub>2</sub>], [Bu<sub>4</sub>N]<b>10</b>, and
[(Cu(IMes)(STrip)] (<b>13</b>) proceed readily by chloride displacement
from CuCl and [Cu(IMes)Cl], respectively. Reaction of <b>10</b> with Ph<sub>3</sub>SiSH or Me<sub>3</sub>SiI produces the heteroleptic
species [Cu(STrip)(SSiPh<sub>3</sub>)]<sup>−</sup> (<b>11</b>) and [Cu(STrip)I]<sup>−</sup> (<b>12)</b>, detected
by mass spectrometry, in mixture with the homoleptic bis(thiolate)
anions. Structural identification by X-ray crystallography of the
ligand precursor molecules 9-(thioacetyl)anthracene (<b>4</b>, triclinic and orthorhombic polymorphs), <i>tert</i>-butyl
9-anthracenyl sulfide (<b>7</b>), <b>5</b>, and <i>tert</i>-butyl 1-triptycenyl sulfide (<b>8</b>) are presented.
Crystallographic characterization of bis(9-anthracenyl)sulfide (<b>3</b>), which features a C–S–C angle of 104.0°
and twist angle of 54.8° between anthracenyl planes, is also
given. A crystal structure of [Bu<sub>4</sub>N][(STrip)], [Bu<sub>4</sub>N]<b>9</b>, provides an experimental measure of 144.6°
for the ligand cone angle. The crystal structures of [Bu<sub>4</sub>N]<b>10</b> and <b>13</b> are reported, the former of
which reveals an unexpectedly small C–S···S–C
torsion angle of ∼41° (average of two values), which confers
a near “cis” disposition of the triptycenyl groups with
respect the S–Cu–S axis. This conformation is governed
by interligand π···π and CH···π
interactions. A crystal structure of an adventitious product, [Bu<sub>4</sub>N][(Cu-STrip)<sub>6</sub>(μ<sub>6</sub>-Br)]·[Bu<sub>4</sub>N][PF<sub>6</sub>], [Bu<sub>4</sub>N]<b>14</b>·[Bu<sub>4</sub>N][PF<sub>6</sub>] is described, which reveals a cyclic hexameric
structure previously unobserved in cuprous thiolate chemistry. The
Cu<sub>6</sub>S<sub>6</sub> ring displays a centrosymmetric cyclohexane
chair type conformation with a Br<sup>–</sup> ion residing
at the inversion center and held in place by apparent soft–soft
interactions with the Cu(I) ions
