Formation
of a Dicopper Platform Based Polyrotaxane
Whose “<i>String</i>” and “<i>Bead</i>” Are Constructed from the Same Components
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Abstract
The combination of the dicopper platform
[Cu<sub>2</sub>(<b>L</b>)<sub>2</sub>(THF)<sub>2</sub>] (<b>1</b>·2THF),
where H<sub><b>2</b></sub><b>L</b> is 1,1′-(1,3-phenylene)-bis-4,4-dimethylpentane-1,3-dione,
and 1,4-bis(4-pyridyl)piperazine (bpp), afforded the first example
of a one-dimensional polyrotaxane {[(<b>1</b>)(μ<sub>2</sub>-bpp)][(<b>1</b>)<sub>2</sub>(bpp)<sub>2</sub>]}<sub><i>n</i></sub> whose “<i>string</i>” and
“<i>bead</i>” are constructed from the same
components. The <i>bead</i> of stoichiometry [(<b>1</b>)<sub>2</sub>(bpp)<sub>2</sub>] has a large rectangular cavity of
dimensions 7.40 × 15.64 Å and is threaded onto a stair-like <i>string</i> of composition [(<b>1</b>)(μ<sub>2</sub>-bpp)]<sub><i>n</i></sub>. The formation of the polyrotaxane
is driven by π–π stacking between the <i>string</i> and the <i>beads</i> with precise electronic and steric
complementarity between these components. A pathway for the formation
of the polyrotaxane is proposed
