Synthesis and Structures of Cuprous Triptycylthiolate Complexes

A synthesis of 1-(thioacetyl)­triptycene (5), a convenient
protected form of 1-(thiolato)­triptycene [STrip]−, is described, a key transformation being the high yield conversion
of tert-butyl 1-triptycenyl sulfide (8) to 5 by a protocol employing BBr3/AcCl.
Syntheses of the two-coordinate copper­(I) compounds [Bu4N]­[Cu­(STrip)2], [Bu4N]10, and
[(Cu­(IMes)­(STrip)] (13) proceed readily by chloride displacement
from CuCl and [Cu­(IMes)­Cl], respectively. Reaction of 10 with Ph3SiSH or Me3SiI produces the heteroleptic
species [Cu­(STrip)­(SSiPh3)]− (11) and [Cu­(STrip)­I]− (12), 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 (4, triclinic and orthorhombic polymorphs), tert-butyl
9-anthracenyl sulfide (7), 5, and tert-butyl 1-triptycenyl sulfide (8) are presented.
Crystallographic characterization of bis­(9-anthracenyl)­sulfide (3), 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 [Bu4N]­[(STrip)], [Bu4N]9, provides an experimental measure of 144.6°
for the ligand cone angle. The crystal structures of [Bu4N]10 and 13 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, [Bu4N]­[(Cu-STrip)6(μ6-Br)]·[Bu4N]­[PF6], [Bu4N]14·[Bu4N]­[PF6] is described, which reveals a cyclic hexameric
structure previously unobserved in cuprous thiolate chemistry. The
Cu6S6 ring displays a centrosymmetric cyclohexane
chair type conformation with a Br– ion residing
at the inversion center and held in place by apparent soft–soft
interactions with the Cu­(I) ions.