Crystalline bipyridinium radical complexes and uses thereof
Described herein are methods of generating 4,4′-bipyridinium radical cations (BIPY •+ ), and methods for utilizing the radical-radical interactions between two or more BIPY •+ radical cations that ensue for the creation of novel materials for applications in nanotechnology. Synthetic methodologies, crystallographic engineering techniques, methods of physical characterization, and end uses are described.
1. A complex comprising (a) CBPQT 2(•+) and (b) a compound of formula (I):
wherein the complex has a 3 + charge and is a tris-radical, and
R 1 and R 2 are each independently selected from the group consisting of alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkenyl, alkynyl, alkyleneazido, alkylenecycloalkyl, alkyleneheterocycloalkyl, and alkylenearyl,
or a salt thereof.
2. The complex of claim 1 , wherein the compound of formula (I) has a diameter up to 10 Å, about 5 Å to about 9 Å, or about 6 Å to about 9 Å.
3. The complex of claim 1 , wherein the salt comprises an anion selected from the group consisting of PF 6 − , halo, sulfate, phosphate, acetate, nitrate, trifluoroacetate, and carbonate.
4. The complex of claim 1 , wherein R 1 and R 2 are the same.
5. The complex of claim 1 , wherein R 1 and R 2 are different.
6. The complex of claim 1 , wherein R 1 or R 2 is methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, sec-butyl, t-butyl, pentyl, hexyl, heptyl, or octyl, or R 1 or R 2 is phenyl, substituted phenyl, naphthyl, or substituted naphthyl.
7. The complex of claim 6 , wherein the phenyl or naphthyl is substituted one or more electron withdrawing group.
8. The complex of claim 6 , wherein the phenyl or naphthyl is substituted with one or more electron donating group.
9. The complex of claim 1 in the form of a crystal.
10. The complex of claim 9 , wherein the crystal is a single crystalline form.
11. The complex of claim 1 , wherein R 1 or R 2 is further modified with a polymerizable group.
12. A polymer comprising a complex of claim 11 .
13. A method of making a complex of claim 1 comprising mixing CBPQT 4+ and a di-cation of the compound of formula (I) in the presence of a reducing agent to form the complex.
14. The method of claim 13 , wherein the reducing agent is zinc dust, an electrochemical reductant, ruthenium(II)tri(2,2′-bipyridine) (Ru(bpy) 3 2+ ), nacent hydrogen, sodium amalgam, NaBH 4 , sulfite compounds, Zn(Hg) amalgam, oxalic acid, formic acid, ascorbic acid, or a metal having a redox potential of about 0.76V to about 3.04V.
15. A method of making a crystal of claim 9 comprising crystallizing the complex using slow-vapor diffusion or crystallizing the complex in the presence of an externally applied magnetic field.
16. The method of claim 15 , wherein the magnetic field controls the direction of crystal growth.
17. The method of claim 16 , wherein the magnetic field controls the crystal morphology.
18. The method of claim 17 , wherein the crystal morphology is one or more of prism, pyramid, dipyramid, triganoal bipyramid, square pyramid, fiber, and nanowire.
19. The crystal of claim 9 , wherein the crystal morphology is one or more of prism, pyramid, dipyramid, triganoal bipyramid, square pyramid, fiber, and nanowire.
20. The crystal of claim 9 , wherein the crystal is an electrode.
21. The crystal of claim 20 , wherein the electrode is a component in a battery, solar cell, or charge storage device.