Composite nanoparticles comprising a complexing ligand and methods of preparation thereof

1. A composite nanoparticle comprising a metal, a rare earth element, and a complexing ligand of formula (I):

wherein

R 1 is H, alkyl, arylalkyl, or aryl;

R 2 is H, alkyl, arylalkyl, or aryl;

R 3 is alkylene, -alkylene-arylene-, arylene, or alkylene substituted with alkyl or aryl;

R 4 is alkylene, -alkylene-arylene-, arylene, or alkylene substituted with alkyl or aryl;

R 5 is H, alkyl, arylalkyl, or aryl;

Z is —O—, —S—, —N(H)—, or —N(R 6 )—, wherein R 6 is alkyl; and

n is 0 or 1.

2. The composite nanoparticle of claim 1 , wherein the metal is a transition metal or a post-transition metal.

3. The composite nanoparticle of claim 1 , wherein the metal is selected from the group consisting of iron, cobalt, nickel, manganese, platinum, aluminum, copper, zirconium, and chromium.

4. The composite nanoparticle of claim 1 , wherein the rare earth element is selected from the group consisting of samarium, praseodymium, neodymium, gadolinium, yttrium, dysprosium, and terbium.

5. The composite nanoparticle of claim 1 , wherein the metal is cobalt and the rare earth element is samarium.

6. The composite nanoparticle of claim 1 , wherein the rare earth to the metal element stoichiometric ratio in the composite nanoparticle is selected from the group consisting of 1:1, 1:3, 1:5, 1:7, 1:13, 2:7, 2:17, and 5:19.

7. The composite nanoparticle of claim 1 , wherein the complexing ligand is selected from the group consisting of 2-[2-(dimethylamino)ethoxy]ethanol, 2-[2-(diethylamino)ethoxy]ethanol, 2-{[2-(dimethylamino)ethyl]methylamino}ethanol, and 4-(dimethylamino)-1-butanol.

8. The composite nanoparticle of claim 1 having a mean diameter size from about 2 nm to about 500 nm.

9. The composite nanoparticle of claim 1 having an aspect ratio from 1 to 1000.