Guanidine-functionalized particles and methods of making and using
Guanidine-functionalized particles and methods of making and using such particles.
1. A method of making a guanidine-functionalized particle, comprising:
reacting O-methylisourea hemisulfate with a linker molecule comprising the formula
(RO) n R a 3-n Si—S m —X
where RO is an alkoxy group comprising one or two carbons, or is an acetoxy group,
where n is 1, 2 or 3,
where R a is an unreactive group,
where S is a spacer group comprising a backbone with m atoms,
m is from 2-16, inclusive, and
where X is a primary amine that is capable of reacting with the O-methylisourea to form a guanidine group;
and,
reacting at least one of the RO groups of the linker molecule with a hydroxyl group of the particle to form a covalent bond between the linker molecule and the particle.
2. The method of claim 1 wherein the (RO) n Si moiety comprises a trimethoxysilane moiety.
3. The method of claim 1 wherein the linker molecule is 3-aminopropyltrimethoxysilane.
4. The method of claim 1 wherein the (RO) n Si moiety comprises a triethoxysilane moiety.
5. The method of claim 1 wherein all m atoms of the backbone of the spacer group S are carbon atoms.
6. The method of claim 1 wherein m=3.
7. The method of claim 1 wherein the spacer group S comprises at least one hetero atom.
8. The method of claim 7 wherein the spacer group S comprises at least one secondary amine.
9. The method of claim 8 wherein the linker molecule is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.
10. The method of claim 1 wherein the step of reacting at least one of the RO groups of the linker molecule with a hydroxyl group of the particle to form a covalent bond between the linker molecule and the particle, is performed after the reacting of the O-methylisourea hemisulfate with the linker molecule.
11. The method of claim 1 wherein the step of reacting at least one of the RO groups of the linker molecule with a hydroxyl group of the particle to form a covalent bond between the linker molecule and the particle, is performed before the reacting of the O-methylisourea hemisulfate with the linker molecule.
12. The method of claim 1 wherein the particle is an insoluble inorganic porous particle.
13. The method of claim 12 wherein the particle comprises vitrous SiO 2 .
14. The method of claim 13 wherein the particle comprises surface hydroxyl groups.
15. The method of claim 14 wherein the particle is a silica particle.
16. The method of claim 15 wherein the particle is a silica gel particle.
17. The method of claim 16 wherein the silica gel particle comprises a particle size of about 25-100 microns and a pore size of about 60-2000 Angstroms.
18. The method of claim 1 wherein residual hydroxyl groups are present on a surface of the particle after the reacting of the at least one of the RO groups of the linker molecule with a hydroxyl group of the particle to form a covalent bond between the linker molecule and the particle.
19. The method of claim 1 wherein the method does not include a step of equilibrating the particle in an atmosphere having a defined relative humidity prior to the reacting of the at least one of the RO groups of the linker molecule with a hydroxyl group of the particle to form a covalent bond between the linker molecule and the particle.