Heteroporphyrin nanotubes and composites

1. A metal nanostructure, comprising:

a porphyrin nanotube with a hollow interior, the porphyrin nanotube having an outer surface; and

a metal nanorod within the hollow interior, the metal nanorod having a first end and a second end.

2. The metal nanostructure of claim 1 , further comprising a metal ball attached to the first end of the metal nanorod.

3. The metal nanostructure of claim 1 , further comprising a metal film on the outer surface of the porphyrin nanotube.

4. The metal nanostructure of claim 1 , further comprising a metal particle on the outer surface of the porphyrin nanotube.

5. The metal nanostructure of claim 1 , wherein the porphyrin nanotube comprises a metalloporphyrin with a coordinated metal ion.

6. The metal nanostructure of claim 5 , wherein the coordinated metal ion is selected from the group consisting of antimony, cobalt, iron, tin, titanium, and vanadium.

7. The metal nanostructure of claim 5 , wherein the metalloporphyrin is selected from the group consisting of Co(III)meso-tetrakis(4-pyridyl)porphyrin, Fe(III)meso-tetrakis(4-pyridyl)porphyrin, Sb(IV)meso-tetrakis(4-pyridyl)porphyrin, Sn(IV)meso-tetrakis meso-tetrakis(4-pyridyl)porphyrin, TiO meso-tetrakis(4-pyridyl)porphyrin, VO meso-tetrakis(4-pyridyl)porphyrin, Co(III)meso-tetrakis(3-pyridyl)porphyrin, Fe(III)meso-tetrakis(3-pyridyl)porphyrin, Sb(IV)meso-tetrakis(3-pyridyl)porphyrin and Sn(IV)meso-tetrakis(3-pyridyl)porphyrin, TiO meso-tetrakis(3-pyridyl)porphyrin, and VO meso-tetrakis(3-pyridyl)porphyrin.

8. The metal nanostructure of claim 1 , wherein the porphyrin nanotube comprises J-aggregated porphyrins.

9. The metal nanostructure of claim 1 , wherein the metal nanostructure comprises at least one material selected from the group consisting of Au, Pt, Pd, Ag, Fe, Co, Ni, Cu, Rh, Pb, Se, CrO 2 , RuO 2 , and UO 2 .

10. A metal nanostructure, comprising:

a porphyrin nanotube with a hollow interior, the porphyrin nanotube having an outer surface;

a first metal nanorod within the hollow interior, the first metal nanorod having a first end and a second end; and

a second metal deposit on the outer surface.

11. The metal nanostructure of claim 10 , further comprising a metal ball attached to the first end of the first metal nanorod.

12. The metal nanostructure of claim 10 , wherein the first metal nanorod and the second metal deposit comprise at least one material selected from the group consisting of Au, Pt, Pd, Ag, Fe, Co, Ni, Cu, Rh, Pb, Se, CrO 2 , CrO 3 , RuO 2 , and UO 2 .

13. The metal nanostructure of claim 10 , wherein the first metal nanorod and the second metal deposit contain at least one different metallic element.

14. The metal nanostructure of claim 10 , wherein the porphyrin nanotube comprises a metalloporphyrin with a coordinated metal ion.

15. The metal nanostructure of claim 14 , wherein the coordinated metal ion is selected from the group consisting of antimony, cobalt, iron, tin, titanium, and vanadium.

16. A metal nanostructure comprising a ball-and-rod nanostructure, made by a method comprising:

preparing a solution of a porphyrin nanotube, a metal precursor, and an electron donor, the porphyrin nanotube having a hollow interior, a first end, and a second end;

illuminating the solution with a light beam at a wavelength that produces a photoexcitation of the porphyrin nanotube, thereby making a photoexcited porphyrin-nanotube template;

photoreducing the metal precursor by means of the photoexcited porphyrin-nanotube template to form a metal nanorod inside the hollow interior of the porphyrin nanotube,

photoreducing the metal precursor by means of the photoexcited porphyrin-nanotube template to form a metal ball continuously attached to the metal nanorod at the first end of the porphyrin nanotube to form the ball-and-rod nanostructure; and

removing the porphyrin nanotube from the ball-and-rod nanostructure using a basic solution.

17. The metal nanostructure of claim 16 , wherein a diameter of the metal nanorod is between about 5 nm and about 200 nm and a diameter of the metal ball is between the diameter of the metal nanorod and 1 micrometer.