Conducting Polymetallorotaxanes: Metal Ion Mediated Enhancements in Conductivity and Charge Localization.

TitleConducting Polymetallorotaxanes: Metal Ion Mediated Enhancements in Conductivity and Charge Localization.
Publication TypeJournal Article
Year of Publication1997
AuthorsZhu, SS, Swager, TM
JournalJournal of the American Chemical Society
Keywordsbithiophenylbipyridine polymetallorotaxane prepn, copper contg polythiophene rotaxane prepn cond, ethylenedioxybithiophenylbipyridine polymetallorotaxane prepn, macrocyclic phenanthroline polymetallorotaxane prepn, polymetallorotaxane prepn elec cond, zinc contg polythiophene rotaxane prepn cond

In this paper polymers are described of two metallorotaxane systems, Rot(1,M) and Rot(2,M) (M = Zn2+ or Cu1+), which are formed by complexing a macrocyclic phenanthroline, a 5,5'-bis([2,2'-bithiophen]-5-yl)-2,2'-bipyridine (ligand 1) or 5,5'-bis(3,4:3',4'-bis(ethylenedioxy)[2,2'-bithiophen]-5-yl)-2,2'-bipyridine (ligand 2), and Zn2+ or Cu1+ ions. The corresponding polymetallorotaxanes, PolyRot(1,M) and PolyRot(2,M), are produced by oxidative polymn. of Rot(1,M) and Rot(2,M). Investigations of the electrochem., conducting, and optical properties of the metallorotaxanes and polymetallorotaxanes as well as related nonrotaxane polymers Poly(1) and Poly(2) are reported. The combined electrochem. and cond. studies of PolyRot(1,M) and PolyRot(2,M) indicated that the polymetallorotaxane's redox and conducting properties were dramatically affected by the Lewis acidic and redox properties of the coordinated metal ions. The Lewis acidity produces charge localization and a redox conduction process in both polymetallorotaxane systems. The matching of the polymer and Cu1+/2+ couple redox potentials in PolyRot(2,Cu) resulted in a Cu1+/2+ contribution to cond. The metal-free PolyRot(1) and PolyRot(2) were produced by extg. the metal ions, and these polymers reversibly bound Zn2+ or Cu2+ ions in soln. The Cu2+ dopes the films of PolyRot(2) and Poly(2), which have lower oxidn. potential than those of PolyRot(1), to produce 106-107-fold cond. increases. In the case of PolyRot(1) and Poly(1), the rotaxane structure was demonstrated to be key for reversible complexation of metal ions. [on SciFinder(R)]