Ethylene sensor

1. A sensor comprising:

a conductive material comprising a carbon-carbon multiple bond moiety, the conductive material being in electrical communication with at least two electrodes, wherein the conductive material includes a plurality of carbon nanotubes; and

a transition metal complex mixed with the conductive material, wherein the transition metal complex is capable of forming a stable complex with ethylene and capable of interacting with the carbon-carbon multiple bond moiety.

2. The sensor of claim 1 , wherein the transition metal complex is associated with the carbon nanotube by coordination of the transition metal to the carbon-carbon multiple bond moiety.

3. The sensor of claim 1 , wherein the transition metal complex is associated with the carbon nanotube by a covalent link between the carbon nanotube and a ligand of the transition metal complex.

4. The sensor of claim 1 , wherein the transition metal complex is associated with the carbon nanotube by a polymer which is non-covalently associated with the carbon nanotube.

5. The sensor of claim 1 , wherein the transition metal complex is bound to the carbon-carbon multiple bond moiety of the conductive material.

6. The sensor of claim 1 , wherein the transition metal complex has formula (I):

wherein:

M is a transition metal;

each R 1 , independently, is H, halo, alkyl, or haloalkyl;

each R 2 , independently, is H, halo, alkyl, haloalkyl, or aryl;

R 3 is H or alkyl; and

L is absent or represents a ligand;

or the transition metal complex has formula (II):

wherein:

M is a transition metal;

each R 4 , independently, is alkyl, haloalkyl, aryl, or trialkylsilyl;

A is —CH(R 5 )—X—CH(R 5 )— wherein X is N or CH, and each R 5 , independently, is H, halo, alkyl, or haloalkyl; or A is —P(R 6 ) 2 —, wherein each R 6 , independently, is alkyl; and

L is absent or represents a ligand.

7. The sensor of claim 6 , wherein the transition metal complex has the formula:

wherein:

each R 1 , independently, is H, methyl, or trifluoromethyl;

each R 2 , independently, is H, methyl, trifluoromethyl, or phenyl;

R 3 is H or methyl; and

L is absent, a thiol, or a carbon-carbon multiple bond.

8. The sensor of claim 1 , wherein the transition metal complex and the carbon-carbon multiple bond moiety are mixed with a polymer.

9. The sensor of claim 8 , wherein the carbon-carbon multiple bond moiety is a carbon nanotube and the polymer is a polymer bead.

10. A method of sensing ethylene, comprising: exposing a sensor to a sample, the sensor including:

a conductive material comprising a carbon-carbon multiple bond moiety, the conductive material being in electrical communication with at least two electrodes, wherein the conductive material includes a plurality of carbon nanotubes; and

a transition metal complex capable of forming a stable complex with ethylene and interacting with the carbon-carbon multiple bond moiety; and

measuring an electrical property at the electrodes.

11. The method of claim 10 , wherein the sample is a gas.

12. The method of claim 10 , wherein the electrical property is resistance or conductance.

13. The method of claim 10 , wherein the transition metal complex is associated with the carbon nanotube by coordination of the transition metal to the carbon-carbon multiple bond moiety.

14. The method of claim 10 , wherein the transition metal complex is associated with the carbon nanotube by a covalent link between the carbon nanotube and a ligand of the transition metal complex.

15. The method of claim 10 , wherein the transition metal complex is associated with the carbon nanotube by a polymer which is non-covalently associated with the carbon nanotube.

16. The method of claim 10 , wherein the transition metal complex is bound to the carbon-carbon multiple bond moiety of the conductive material.

17. The method of claim 10 , wherein the transition metal complex has formula (I):

wherein:

M is a transition metal;

each R 1 , independently, is H, halo, alkyl, or haloalkyl;

each R 2 , independently, is H, halo, alkyl, haloalkyl, or aryl;

R 3 is H or alkyl; and

L is absent or represents a ligand;

or the transition metal complex has formula (II):

wherein:

M is a transition metal;

each R 4 , independently, is alkyl, haloalkyl, aryl, or trialkylsilyl;

A is —CH(R 5 )—X—CH(R 5 )—wherein X is N or CH, and each R 5 , independently, is H, halo, alkyl, or haloalkyl; or A is —P(R 6 ) 2 —, wherein each R 6 , independently, is alkyl; and

L is absent or represents a ligand.

18. The method of claim 17 , wherein the transition metal complex has the formula:

wherein:

each R 1 , independently, is H, methyl, or trifluoromethyl;

each R 2 , independently, is H, methyl, trifluoromethyl, or phenyl;

R 3 is H or methyl; and

L is absent, a thiol, or a carbon-carbon multiple bond.

19. A method of making a sensor comprising:

forming a complex including a conductive material comprising a carbon-carbon multiple bond moiety, and a transition metal complex capable of forming a stable complex with ethylene and interacting with the carbon-carbon multiple bond moiety; and

placing the conductive material in electrical communication with at least two electrodes^ wherein the conductive material includes a plurality of carbon nanotubes.

20. The method of claim 19 , wherein the transition metal is copper.

21. The method of claim 19 , wherein the electrodes are gold.

22. The method of claim 19 , wherein the sensor is configured to sense ethylene.

23. The method of claim 19 , wherein the complex is Cu(I) scorpionate.

24. The method of claim 19 , wherein placing the conductive includes drop-casting a solution of the transition metal complex and a polymer onto the at least two electrodes.

25. The method of claim 24 , wherein the polymer can be selected from the group consisting of a hydrophobic polymer, a fluorinated polymer, a conjugated or partially conjugated polymer and combinations thereof.

26. The method of claim 19 , further comprising combining the complex mixture with a selector.

27. The method of claim 19 , wherein the selector includes a transition metal salt.

28. A method of making a sensor comprising:

forming a complex including a conductive material comprising a carbon-carbon multiple bond moiety, and a transition metal complex capable of forming a stable complex with ethylene and interacting with the carbon-carbon multiple bond moiety, wherein the conductive material includes a plurality of carbon nanotubes: spray drying the complex at a temperature to obtain a viscous conductive material; and placing the viscous conductive material in electrical communication with at least two electrodes.

29. The method of claim 28 , wherein the temperature is between 100 and 210° C.

30. The method of claim 28 , wherein the spray drying takes place in an inert atmosphere.