Infrared light absorbing aminium and diimmonium compositions

Abstract

Disclosed are infrared light absorbing aminium and diimmonium compositions that have at least one absorption maximum in the infrared spectral region between about 700 and 1500 nm and that are useful, for example, as infrared absorbers. In one example, an infrared light aminium absorbing composition includes an anionic borate moiety and an aminium radical cation, which has at least one absorption peak in the near infrared wavelength region between about 700 and 1500 nm. In another example, an infrared light diimmonium absorbing composition includes two anionic borate moieties and a diimmonium radical cation, which has at least one absorption peak in the near infrared wavelength region between about 700 and 1500 nm. Such compositions may be incorporated into films or bulk materials to form light filters for electromagnetic radiation, including laser radiation.

Claims

1. An infrared light absorbing aminium composition comprising: an aminium radical cation that has at least one absorption peak in the near infrared wavelength region between about 700 and 1500 nm and having the formula:
[4-R.sup.1R.sup.2NC.sub.6H.sub.3CH.sub.3][4-R.sup.3R.sup.4NC.sub.6H.sub.3CH.sub.3][4-R.sup.5R.sup.6NC.sub.6H.sub.3CH.sub.3]N.sup.+ where R.sup.1 through R.sup.6 are identical or different, optionally are linked to form rings, and are each an alkyl group, an arylalkyl group, an alkyl ether, or hydroxyalkyl group, and an anionic borate moiety having the formula:
[BX.sub.aY.sub.b].sup. in which a and b are integers, and a ranges from 0 to 3, b ranges from 1 to 4, and a+b=4; each X is a halogen atom, which is identical or different or an OH functional group, and each Y, which is identical or different, is a phenyl radical, which is substituted by at least one element or electron-withdrawing substituent or by one or more halogen atoms, or an aryl radical containing at least two aromatic ring members, which is optionally substituted.

2. The composition of claim 1, wherein R.sup.1 through R.sup.6 are hydrocarbons, having the formula (4-G.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N.sup.+., wherein each G is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isoamyl, hexyl, oxtyl, ethylhexyl, decyl, dodecyl, or benzyl.

3. The composition of claim 1, wherein the anionic borate moiety is (C.sub.6F.sub.5).sub.4B.sup..

4. The composition of claim 1, wherein the anionic borate moiety is selected from [3,5-bis(CF.sub.3).sub.2C.sub.6H.sub.3].sub.4B.sup., [(CF.sub.3)C.sub.6H.sub.4].sub.4B.sup., [(C.sub.6F.sub.5).sub.3BF].sup., [(C.sub.6F.sub.5).sub.2BF.sub.2].sup. or [(C.sub.6F.sub.5)BF3].sup..

5. The composition of claim 1, wherein R.sup.1 through R.sup.6 is n-butyl.

6. The composition of claim 1, wherein the methyl group on each arene in the aminium radical cation formula is ortho- to the central nitrogen.

7. A filter or filter element including the composition of claim 1, alone or in combination with one or more dyes, absorbers and/or additives.

8. A filter or filter element including the composition of claim 1, which is chemically bound to an oligomer or polymer.

9. The filter or filter element of claim 7 further including a liquid, gel, or solid in which the composition is dispersed.

10. The filter or filter element of claim 7 defining one of an optical wavelength filter, display filter, illumination source filter or laser radiation filter.

11. A contact lens including the composition of claim 1.

12. An infrared light absorbing diimonium composition comprising: a diimonium radical dication that has at least one absorption peak in the near infrared wavelength region between about 700 and 1500 nm and having the formula:
[4-R.sup.1R.sup.2NC.sub.6H.sub.3CH.sub.3][4-R.sup.3R.sup.4NC.sub.6H.sub.3CH.sub.3][4-R.sup.5R.sup.6NC.sub.6H.sub.3CH.sub.3]N.sup.+2 where R.sup.1 through R.sup.6 are identical or different, optionally are linked to form rings, and are each an alkyl group, an arylalkyl group, an alkyl ether or hydroxyalkyl group, and two anionic borate moieties, with each being identical or different and having the formula:
[BX.sub.aY.sub.b].sup. in which a and b are integers, and a ranges from 0 to 3, b ranges from 1 to 4, and a+b=4; each X is a halogen atom, which is identical or different or an OH functional group, and each Y, which is identical or different, is a phenyl radical, which is substituted by at least one element or electron-withdrawing substituent or by one or more halogen atoms, or an aryl radical containing at least two aromatic ring members, which is optionally substituted.

13. The composition of claim 12, wherein R.sup.1 through R.sup.6 are hydrocarbons, having the formula (4-G.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N.sup.+2, wherein each G is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isoamyl, hexyl, oxtyl, ethylhexyl, decyl, dodecyl, or benzyl.

14. The composition of claim 12, wherein at least one anionic borate moieties is (C.sub.6F.sub.5).sub.4B.sup..

15. The composition of claim 12, at least one anionic borate moiety is selected from [3,5-bis(CF.sub.3).sub.2C.sub.6H.sub.3].sub.4B.sup., [(CF.sub.3)C.sub.6H.sub.4].sub.4B.sup., [(C.sub.6F.sub.5).sub.3BF].sup., [(C.sub.6F.sub.5).sub.2BF.sub.2].sup. or [(C.sub.6F.sub.5)BF3].sup..

16. The composition of claim 12, wherein R.sup.1 through R.sup.6is n-butyl.

17. The composition of claim 12, wherein the methyl group on each arene in the diimonium radical dication formula is ortho- to the central nitrogen.

18. A filter or filter element including the composition of claim 12, alone or in combination with one or more dyes, absorbers or additives.

19. A filter or filter element including the composition of claim 12, which is chemically bound to an oligomer or polymer.

20. The filter or filter element of claim 18 further including a liquid, gel, or solid in which the composition is dispersed.

21. The filter or filter element of claim 18 defining one of an optical wavelength filter, display filter, illumination source filter or laser radiation filter.

22. A contact lens including the composition of claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention.

(2) FIG. 1 is an infrared light absorbing composition in accordance with an embodiment of the invention including an aminium radical cation with one methyl group on each arene and ortho- to the central nitrogen;

(3) FIG. 2 is an infrared light absorbing composition in accordance with an embodiment of the invention including a diimmonium dication with one methyl group on each arene and ortho- to the central nitrogen;

(4) FIG. 3 is a graph that demonstrates the shift to longer wavelengths in two infrared light absorbing compositions including an aminium radical cation, with 0 and 3 methyl groups; and

(5) FIG. 4 is a graph that demonstrates the shift to longer wavelengths in two infrared light absorbing compositions including a diimmonium dication, with 0 and 3 methyl groups.

DETAILED DESCRIPTION

(6) The present invention is directed to infrared light absorbing aminium and diimmonium compositions that have at least one absorption maximum between about 700 nm and 1500 nm, and filters or sensing materials including these compositions.

(7) In one embodiment, there is provided an infrared light aminium absorbing composition including an anionic borate moiety and an aminium radical cation, which has at least one absorption peak in the near infrared wavelength region between about 700 and 1500 nm. The aminium radical cationic can include the formula [4-R.sup.1R.sup.2NC.sub.6H.sub.3CH.sub.3][4-R.sup.3R.sup.4NC.sub.6H.sub.3CH.sub.3][4-R.sup.5 R.sup.6NC.sub.6H.sub.3CH.sub.3]N.sup.+., and the anionic borate moiety can have the formula [BX.sub.aY.sub.b].sup..

(8) With respect to the aminium radical cation, R.sup.1 through R.sup.6 can be identical or different, optionally are linked to form rings and are each an alkyl group, an arylalkyl group, an alkyl ether group or hydroxy alkyl group, optionally linked or chemically bound to an oligomer or polymer. The peak absorption wavelength can be tuned by changing the R groups. And with respect to the anionic borate moiety, a and b can be integers and a can range from 0 to 3 and b can range from 1 to 4, and a+b=4. Each X can be a halogen atom, which may be identical or different or an OH functional group, and each Y, which may be identical or different, can be a phenyl radical, which is substituted by at least one element or electron-withdrawing substituent, such as a perfluoroalkyl group, or by one or more halogen atoms or an aryl radical containing at least two aromatic ring members, which is optionally substituted.

(9) As shown in FIG. 1, in one example, the infrared light absorbing aminium composition includes a tri-methyl aminium ion wherein each of the CH.sub.3 groups in the formula is ortho- to the central nitrogen. This infrared light absorbing aminium composition shows a distinctive infrared absorption band near 1062 nm in acetone and near 1075 nm in polycarbonate resin when R.sup.1R.sup.6=n-butyl. In another example, the alkyl ether group can include oligo ethylene glycol ethers. In another example, the hydroxy alkyl group can include hydroxy ethyl.

(10) In another example, R.sup.1 through R.sup.6can be hydrocarbons having the formula (4-G.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N.sup.+., wherein each G is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isoamyl, hexyl, octyl, ethylhexyl, decyl, dodecyl or benzyl. In another example, R.sup.1 through R.sup.6 is n-butyl.

(11) In another embodiment, there is provided an infrared light absorbing diimmonium composition including two anionic borate moieties, which may be the same or different, and a diimonium dication, which has at least one absorption peak in the near infrared wavelength region between about 700 and 1500 nm. The diimmonium radical dication can have the formula [(4-R.sup.1R.sup.2NC.sub.6H.sub.3CH.sub.3)(4-R.sup.3R.sup.4NC.sub.6H.sub.3CH.sub.3)NC.sub.6H.sub.3CH.sub.3NR.sup.5R.sup.6].sup.2+, and the anionic borate moiety can have the formula [BX.sub.aY.sub.b].sup..

(12) with respect to the diimmonium radical dication, R.sup.1 through R.sup.6 can be identical or different, optionally are linked to form rings and are each an alkyl group, an arylalkyl group, an alkyl ether group or hydroxy alkyl group, optionally linked or chemically bound to an oligomer or polymer. The peak absorption wavelength can be tuned by changing the R groups. And with respect to the anionic borate moiety, a and b can be integers and a can range from 0 to 3 and b can range from 1 to 4, and a+b=4. Each X can be a halogen atom, which may be identical or different or an OH functional group, and each Y, which may be identical or different, can be a phenyl radical, which is substituted by at least one element or electron-withdrawing substituent, such as a perfluoroalkyl group or by one or more halogen atoms, or an aryl radical containing at least two aromatic ring members, which is optionally substituted.

(13) As shown in FIG. 2, in one example, the infrared light absorbing diimmonium composition includes a tri-methyl diimmonium ion wherein each of the CH.sub.3 groups in the formula is ortho- to the central nitrogen. In another example, the alkyl ether group can include oligo ethylene glycol ethers. In another example, the hydroxy alkyl group can include hydroxy ethyl.

(14) In another example, R.sup.1 through R.sup.6 can be hydrocarbons having the formula (4-G.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N.sup.+2, wherein each G is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isoamyl, hexyl, octyl, ethylhexyl, decyl, dodecyl or benzyl. In another example, R.sup.1 through R.sup.6is n-butyl.

(15) In one example, the anionic borate moiety in the infrared light absorbing aminium or diimmonium composition can include [3,5-(CF.sub.3).sub.2C.sub.6H.sub.3].sub.4B.sup., [(CF.sub.3)C.sub.6H.sub.4].sub.4B.sup., [(C.sub.6F.sub.5).sub.3BF].sup., [(C.sub.6F.sub.5).sub.2BF.sub.2].sup., [(C.sub.6F.sub.5).sub.2BF.sub.3].sup., (C.sub.6F.sub.5).sub.4B.sup., or [(CF.sub.3)C.sub.6H.sub.2F.sub.2].sub.4B.sup.. In another example, the borate anion is (C.sub.6F.sub.5).sub.4B.sup..

(16) In another embodiment, the infrared light absorbing composition further includes a host associated therewith to form an optical filter capable of filtering light.

(17) With respect to the ortho- positioned methyl groups, by incorporating the methyl groups onto the phenyl rings in positions ortho- to the central nitrogen in the infrared light absorbing composition, the infrared band shifts to longer wavelengths and the blue violet band simultaneously and unexpectedly shifts to shorter wavelengths relative to those compositions without the methyl groups. The effect of these dual shifts of both the visible and infrared bands serves to reduce the apparent color and increase the blue and red light transmission of a light filter designed for a particular optical density at wavelengths near 1000-1200 nm in the infrared, regardless of the specific application of the filter.

(18) Also, the infrared light absorbing compositions that incorporate one or more methyl groups onto the phenyl rings in positions ortho- to the central nitrogen, unexpectedly show, in some cases, melting points near or below room temperature and generally have very high solubility in organic solvents. The high solubility of the dyes in organic solvents facilitates the fabrication of thin film filters comprised of such dyes.

(19) The light absorbing aminium and diimmonium compositions generally absorb infrared light over a range of wavelengths and are useful for various light-filtering applications. The compositions may further include more than one light-absorbing compound. The additional light-absorbing compound(s) may also be aminium salts, diimmonium salts, polymethines, porphyrins, azaporphyrins, phthalocyanines, squarylium compounds, dithiolenes, etc., as such compounds are well known in the art. The compositions may also include additional reflective, refractive and/or diffractive elements capable of filtering and or transmitting optical radiation from the ultraviolet wavelengths through the infrared wavelengths. Furthermore, other dyes, light stabilizers, UV-absorbers, anti-oxidants, quenchers and the like may be included in the composition.

(20) When combined with a host, the infrared light-absorbing compositions, and other optional compounds, can generally form a light-filtering device. The host is generally either a liquid, a gel or a solid. For example, the host may be a matrix material or a film. In one embodiment, the host is a material selected from the group consisting of polycarbonate, polystyrene, polyvinyl chloride, polyacrylate, polyurethane, polymethylmethacrylate, silicone, silicon-based polymers, glass, sol-gel, hydrogel, polycrystalline materials, plastic, cellulose derivatives and combinations thereof. The light absorbing aminium or diimmonium compositions may be, without limitation, a coating on or an integral part of the host material. For example, optical filters may be fabricated by one of several conventional methods, such as injection molding, for incorporating the compositions into or onto various hosts.

(21) The resulting filter may include other additives or dyes to provide, for example, UV stabilization or a tailored spectral curve. The filter includes a host in combination with at least one of the light absorbing aminium or diimmonium compositions that has at least one absorption maximum in the near infrared spectral region between about 700 and 1500 nm. Again, such light absorbing aminium and diimmonium compositions can be useful in filters, either alone or in combination with other absorptive, reflective, refractive, or diffractive elements for optical radiation from the ultraviolet through the infrared.

(22) With respect to preparation of the light absorbing aminium and diimmonium compositions, by way of example, the aminium cation of the type shown in FIG. 1 can be prepared from (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N and about one equivalent of a silver salt, for example, Ag.sup.+(C.sub.6F.sub.5).sub.4B.sup., in a suitable solvent, such as methylene chloride, under conditions known to be useful for the synthesis of aminium cations. The resulting product may be isolated and purified by techniques such as extraction, crystallization, and chromatographic separation. More specifically, theamine (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N can be prepared in multiple steps. First, the triaryl framework can be prepared from 2-fluoro-5-nitrotoluene and 2-methyl-4-nitroaniline in two steps in DMF solvent according to the known methods described by Gorvin, J. C. S. Perkin Transactions I, 1988, pp 1331-1335, which is incorporated herein by reference in its entirety. Then, reduction of the resulting (4-O.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N intermediate can be carried out by use of hydrazine hydrate in DMF over a Pd/C catalyst and the resulting (4-H.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N can be alkylated by standard techniques with an alkyl halide, by example, 1-bromobutane in DMF with K.sub.2CO.sub.3 or 1-iodobutane in ethanol with Na.sub.2CO.sub.3. The aminium cation with a borate counterion (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N.sup.+.(C.sub.6F.sub.5).sub.4B.sup. was prepared by the addition of a solution of about 1 equivalent of Ag.sup.+(C.sub.6F.sub.5).sub.4B.sup. in methylene chloride to a solution of (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N in methylene chloride from about 20 to about 0 C. After warming the solution to room temperature overnight, the precipitate was filtered off and the filtrate was purified by chromatography on silica gel with methylene chloride eluent. The peak wavelength of the dye in acetone was observed at about 1062 nm and the edge of the violet band was observed at about 436 nm. Notably, the peak wavelength of the aminium composition with three methyl groups is shifted about 70 nm to longer wavelengths from the dye without the added methyl groups. SeeTables I and II below, which are discussed next. See also FIG. 3, which shows absorption spectra of the prepared aminium composition for 0 and 3 methyl groups (in the ortho position to the central nitrogen), normalized at the infrared peak, R.sup.1-R.sup.6=butyl.

(23) Tables I and II below list the wavelength of infrared light absorbing aminium compositions with 0 and 3 methyl groups (in the ortho position to the central nitrogen). The observation that the peak wavelengths of aminium compositions increase with changes in alkyl groups on the nitrogen from, for example, ethyl to butyl is well known. However, less well understood is the effect of one or more methyl groups on the phenyl rings and ortho- to the central nitrogen. The reason for the effect of the methyl groups on peak wavelength may or may not be associated with an increase in propeller angle of the phenyl groups at the central nitrogen.

(24) Overall, the improvement in blue and red light transmission as well as the solubility of the infrared absorbing tri(methylphenyl) compositions was unexpected.

(25) TABLE-US-00001 TABLE I Aminium Chromophore Spectral Properties, Acetone Peak Visible Percentage Full Width Wavelength Cut-off of peak Half (Acetone) wavelength absorption Maximum about (20% of IR at (FWHM, Chromophore +/10 nm absorption) 1064 nm nm) [(Bu.sub.2N)C.sub.6H.sub.4].sub.3N.sup.+. 993 nm 445 nm 39% 179 nm [(Bu.sub.2N)C.sub.6H.sub.4CH.sub.3].sub.3N.sup.+. 1062 nm 436 nm 99% 240 nm

(26) TABLE-US-00002 TABLE II Aminium Chromophore Spectral Properties, Polycarbonate Peak Visible Per- Full Wavelength Cut-off centage Width (Poly- wavelength of peak Half carbonate) (20% of absorp- Maximum about 1064 nm tion at (FWHM, Chromophore +/10 nm absorption) 1064 nm nm) [(Bu.sub.2N)C.sub.6H.sub.4].sub.3N.sup.+. 1005 nm 456 nm 55% 182 nm [(Bu.sub.2N)C.sub.6H.sub.3CH.sub.3].sub.3N.sup.+. 1073 nm 440 nm 99% 250 nm

(27) Further, by way of example, the diimmonium cation of the type shown in FIG. 2 can be prepared from (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N and a minimum of about two equivalents of a silver salt, for example, Ag.sup.+(C.sub.6F.sub.5).sub.4B.sup., in a suitable solvent, such as methylene chloride, under conditions known to be useful for the synthesis of diimmonium cations. The resulting product may be isolated and purified by techniques such as extraction, crystallization, and chromatographic separation. More specifically, the diimmonium dication shown in FIG. 2 with a borate counterion (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N.sup.+2 [(C.sub.6F.sub.5).sub.4B.sup.].sub.2 was prepared by the addition of a solution of about 2 equivalents of Ag.sup.+(C.sub.6F.sub.5).sub.4B.sup. in methylene chloride to a solution of (4-Bu.sub.2NC.sub.6H.sub.3CH.sub.3).sub.3N in methylene chloride from about 20 to about 0 C. Upon warming to room temperature, the precipitate was filtered off and the filtrate was purified by chromatography on silica gel with methylene chloride eluent. The peak wavelength of the dye in methylene chloride was observed at about 975 nm. See also FIG. 4, which shows the absorption spectra of the prepared diimmonium composition for 0 and 3 methyl groups(in the ortho- position to the central nitrogen), normalized at the infrared peak, showing increasing peak wavelength in nanometers with increasing number of methyl groups.

(28) While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will be readily apparent to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrated examples described. Accordingly, departures may be made from such details without departing from the scope of the Applicant's general inventive concept.