PHOTOCHROMIC AND ELECTROCHROMIC COMPOUNDS AND SYNTHESIS AND USE THEREOF

• US 20100190868A1
• Filed: 05/25/2006
• Published: 07/29/2010
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Solutia Canada, Inc. (Eastman Chemical Company)
• Original Assignee: Switch Materials, Inc.
• Inventors: Gauthier, Simon, Wuestenberg, Bettina, Adams, Michael, Lemieux, Vincent, Branda, Neil R.
• Granted Patent: US 8,536,205 B2
• Time in Patent Office: Days
• US Class Current: 514/772
• CPC Class Codes: C07D 333/18 by sulfur atoms
• CPC Class Codes: C07D 333/22 Radicals substituted by doubly bound hetero atoms, or by two hetero atoms other than halogen singly bound to the same carbon atom
• CPC Class Codes: C07D 333/24 Radicals substituted by carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals
• CPC Class Codes: C07D 333/28 Halogen atoms
• CPC Class Codes: C07D 333/78 condensed with rings other than six-membered or with ring systems containing such rings
• CPC Class Codes: C07D 409/08 linked by a carbon chain containing alicyclic rings
• CPC Class Codes: C07D 409/14 containing three or more hetero rings
• CPC Class Codes: C09K 2211/1007 Non-condensed systems
• CPC Class Codes: C09K 2211/1092 containing sulfur as the only heteroatom
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: Y10T 436/14 Heterocyclic carbon compound [i.e. , O, S, N, Se, Te, as only ring hetero atom]
• CPC Class Codes: Y10T 436/142222 Hetero-O [e.g., ascorbic acid, etc.]

Abstract

Novel photochromic and electrochromic hexadiene compounds are described. The compounds are reversibly convertible between ring-open and ring-closed isomeric forms as indicated in structures I(o) and I(c) below. (See formula in original abstract of application) The conversion between the different isomeric forms may be induced by light or electricity. In one embodiment the compounds may include a charge transfer moiety including electron donor and acceptor groups. The electron donor and acceptor are linearly conjugated in the ring-open form to enable electron transfer but are electrically insulated in the ring-closed form. Methods for synthesizing the compounds from photochemically and/or electrically inert precursors are also described. For example, the photoresponsive compounds may be synthesized by reacting diene precursors with dienophiles in a condensation reaction. The compounds may be utilized in reactivity-gated photochromic or electrochromic applications. In one embodiment of the invention, compounds of the invention may be used in a method to selectively release a releasable agent, such as a small molecule. According to this method, a photochemically inert precursor compound is reacted with the releasable agent to form a carrier compound comprising a switching moiety, the switching moiety being reversibly convertible between a thermally unstable form and a thermally stable form. The switching moiety may be selectively converted between the first and second forms to cause controlled release of the releasable agent from the carrier compound.

Claims

1. A compound reversibly convertible between a first ring-open isomeric form represented by the formula I(o) and a second ring-closed isomeric form represented by I(c)

wherein X is a heteroatom selected from the group consisting of S, N and O;

R₁ is selected from the group consisting of H, a halogen, alkyl, aryl and substituted aryl;

R₂ is selected from the group consisting of alkyl, aryl and substituted aryl;

R₃ is selected from the group consisting of H and alkyl;

R₄ is selected from the group consisting of H, alkyl, aryl, substituted aryl, an electron-donating group, an electron-accepting group, and a constituent of an optionally substituted heterocycle;

R₅ is selected from the group consisting of alkyl, aryl, substituted aryl, an electron-donating group and an electron-accepting group;

R₆ is selected from the group consisting of alkyl, aryl, substituted aryl, an electron-donating group, an electron-accepting group and a constituent of an optionally substituted heterocycle; and

R₇ and R₈ are each selected from the group consisting of a constituent of a 5 membered ring comprising H or a halogen or an optionally substituted 6 membered ring;

wherein, when R₄ and R₆ are constituents of a thiophene ring and R₅ is an alkyl, aryl or substituted aryl, then R₇ and R₈ are constituents of an optionally substituted six-membered ring;

and wherein, when R₇ and R₈ are constituents of a 5 membered halogenated ring then R₄, R₅ and R₆ are independently not an alkyl or aryl.

2. The compound as defined in claim 1, wherein said compound is convertible between said first and second isomeric forms in response to a light stimulus.

3. The compound as defined in claim 1, wherein said compound is convertible between said first and second isomeric forms in response to an electrical stimulus.

4. The compound as defined in claim 2, wherein said compound is converted from said first form to said second form in response to ultraviolet light and is converted from said second form to said first form in response to visible light.

5. The compound as defined in any one of the preceding claims, wherein R₇ and R₈ together comprise a pentene ring.

6. The compound as defined in claim 5, wherein said pentene ring is halogenated.

7. The compound as defined in claim 6, wherein said pentene ring is fluorinated.

8. The compound as defined in any of the preceding claims wherein R₇ and R₈ together comprise an optionally substituted six membered ring.

9. The compound as defined in claim 1, wherein R₄ and R₆ together comprise a heterocycle.

10. The compound as defined in claim 9, wherein said heterocycle is a thiophene ring.

11. The compound as defined in any one of claims 1-10, wherein R₄ comprises an electron-donating group and R₅ and R₆ comprise an electron-accepting group.

12. The compound as defined in any one of claims 1-10, wherein R₄ comprises an electron-accepting group and R₅ and R₆ comprise an electron-donating group.

13. The compound as defined in claims 11 and 12, wherein said electron-donating group and said electron-accepting group are linearly conjugated in said first ring-open form.

14. The compound as defined in claim 13, wherein said electron-donating group and said electron-accepting group are electrically insulated in said second ring-closed form.

15. The compound as defined in any one of claims 11-14, wherein said electron-accepting group is a carbonyl-based functional group.

16. The compound as defined in any one of claims 11-14, wherein said electron-accepting group comprises a dicyanoethylene group.

17. The compound as defined in any one of claims 11-16, wherein said electron-accepting and electron-donating groups are electronically connected to each other by an alkene in said first ring-open form.

18. The compound as defined in any of the preceding claims wherein said first and second isomeric forms are thermally stable.

19. The compound as defined in any one of claims 1-17, wherein said first ring-open isomeric form is thermally unstable and said second ring-closed isomeric form is thermally stable.

20. The compound as defined in claim 1, wherein R₄ is selected from the group consisting of n-C₃H₁, C₆H₅, 4-C₆H₄—

OCH₃, 3,4,5-C₆H₂(OCH₃)₃, 4-C₆H₄—

NO₂ and 4-pyridyl.

26. The compound as defined in claim 21, wherein said compound comprises the structure defined in claim 1.

27. The compound as defined in claim 1 or 26, wherein switching said compound between said first and second forms alters the chemical reactivity of said compound.

42. A method of synthesizing a photoactive hexatriene compound having the structure defined in claim 1, wherein said method comprises:

(a) providing a photochemically inert precursor compound; and

(b) chemically reacting said precursor compound with a reactant to form said photoactive hexatriene compound.

43. The method as defined in claim 42, wherein said step of chemically reacting said precursor and said reactant is reversible.

44. The method as defined in claim 42 or 43, wherein said precursor compound is a diene and wherein said reactant is a dienophile.

45. The method as defined in claim 44, wherein said dienophile is an alkene.

46. The method as defined in claim 42, wherein said chemically reacting is a condensation reaction.

47. The method as defined in claim 42, wherein said chemically reacting is a cycloaddition.

48. The method as defined in claim 42, wherein said precursor comprises a butadiene backbone.

49. The method as defined in claim 42, wherein said precursor is a butadiene derivative.

50. The method as defined in claim 43, wherein said precursor and said reactant are liberated when said chemical reaction is reversed.

21. A chemical compound comprising:

(a) a charge transfer moiety comprising an electron donor and an electron acceptor; and

(b) a switching moiety reversibly convertible between a first form and a second form in response to a light or an electrical stimulus, wherein said electron donor and electron acceptor are linearly conjugated to permit charge transfer when said switching moiety is in said first form and wherein said electron donor and electron acceptor are electronically insulated to prevent charge transfer when said switching moiety is in said second form.

22. The compound as defined in claim 21, wherein said

switching moiety comprises a hexatriene subunit configured in a ring-open configuration in said first form and a ring-closed configuration in said second form.

23. The compound as defined in claim 22, wherein said first and second forms are photoactive.

24. The compound as defined in any one of claims 21-23, wherein conversion of said switching moiety between said first form and said second form causes a change in hybridization of at least one carbon atom connecting said electron donor and said electron acceptor.

25. The compound as defined in claim 21, wherein said charge transfer moiety comprises a dicyanoethylene substituent.

28. The compound as defined in claim 21, wherein said compound is thermally stable in said first and second forms.

29. The compound as defined in claim 21, wherein said compound is thermally unstable in said first form and thermally stable in said second form.

30. A method of selectively releasing a releasable agent comprising:

(a) providing a precursor compound;

(b) reacting said precursor compound with said releasable agent to form a carrier compound, wherein said carrier compound comprises a switching moiety reversibly convertible between a first thermally unstable form and a second thermally stable form in response to a light or an electrical stimulus; and

(c) selectively converting said switching moiety between said second form and said first form to cause controlled release of said releasable agent from said carrier compound.

31. The method as defined in claim 30, wherein said releasable agent is a small molecule.

32. The method as defined in claim 30 or 31, wherein said step of selectively converting said switching moiety comprises exposing said carrier compound to a predetermined wavelength of light.

33. The method as defined in any one of claims 30-32, wherein said carrier compound is delivered to a target location prior to said step of selectively converting said switching moiety.

34. The method as defined in claim 33, wherein said target location is located in vivo.

35. The method as defined in any one of claims 30-34, wherein said switching moiety comprises a hexatriene subunit.

36. The method as defined in claim 30, wherein said carrier compound comprises a charge transfer moiety comprising an electron donor and an electron acceptor, wherein said electron donor and acceptor are and electronically conjugated in said first form and electronically insulated in said second form.

37. The method as defined in claim 36, wherein said precursor is a diene and wherein said reacting comprises chemically reacting said diene with said releasable agent.

38. The method as defined in claim 30, wherein said precursor is photochemically inert.

39. The method as defined in claim 31, wherein said small molecule is selected from the group consisting of therapeutic agents, biochemical effectors, polymer precursors and chemical reagents.

40. The method as defined in claim 30, wherein said method comprises:

(a) providing multiple releasable agents;

(b) coupling each of said multiple releasable agents to said carrier compound; and

(c) selectively releasing said multiple releasable agents by sequentially exposing said carrier compound to different wavelength of light, each of said wavelengths corresponding to at least one of said releasable agents.

41. A photoactive conjugate comprising a compound having a switching moiety reversibly convertible between a first thermally unstable form and a second thermally stable form in response to a light or an electrical stimulus and at least one small molecule bound to said compound, wherein said small molecule is releasable from said compound when said switching moiety is switched from said second form to said first form.

51. A method of testing for the presence of a target compound in a sample comprising:

(a) providing a photochemically inert precursor compound;

(b) chemically reacting said precursor compound with said sample; and

(c) detecting whether said chemical reaction produces a photoactive hexatriene reaction product.

52. A precursor useful for preparation of a photoactive hexatriene compound, wherein said precursor is selected from the group consisting of:

(a) an aldehyde or a ketone capable of reacting with an activated methylene in a dehydration or deoxygenation reaction to form said hexatriene compound; and

(b) a diene capable of reacting with a dienophile in a condensation reaction to form said hexatriene compound.

53. The precursor as defined in claim 52, wherein said precursor is photochemically inert.

54. The precursor as defined in claim 52 or 53, wherein said diene is a butadiene.

55. The precursor as defined in claim 52 or 53, wherein said diene is a cyclopentadiene.

56. The precursor as defined in claim 55 wherein said cyclopentadiene is non-fluorinated.

57. The precursor as defined in claim 52 or 53, wherein said diene is a cyclohexadiene.

58. The precursor as defined in claim 52 or 53, wherein said diene is a fulvene.

59. The precursor as defined in claim 54, wherein diene is represented by the formula II

wherein X is a heteroatom selected from the group consisting of S, N and O;

R₁ is selected from the group consisting of H, a halogen, alkyl, aryl and substituted aryl;

R₂ is selected from the group consisting of alkyl, aryl and substituted aryl;

R₃ is selected from the group consisting of H and alkyl;

R₄ is selected from the group consisting of H, alkyl, aryl, substituted aryl, an electron-donating group, an electron-accepting group, and a constituent of an optionally substituted heterocycle;

R₅ is selected from the group consisting of alkyl, aryl, substituted aryl, an electron-donating group and an electron-accepting group;

R₆ is selected from the group consisting of alkyl, aryl, substituted aryl, an electron-donating group, an electron-accepting group and a constituent of an optionally substituted heterocycle; and

R₇ and R₈ are each selected from the group consisting of a constituent of a 5 or and optionally substituted 6 membered ring.