WO1997019088A1

WO1997019088A1 - Novel nonlinear optical molecules and polymers incorporating them

Info

Publication number: WO1997019088A1
Application number: PCT/US1996/017058
Authority: WO
Inventors: David W. Polis
Original assignee: Hoechst Celanese Corporation
Priority date: 1995-11-21
Filing date: 1996-10-24
Publication date: 1997-05-29

Abstract

Disclosed herein are novel fused rigid rod aromatic multiring molecules of general formula (II) wherein D and A represent electron donor and electron acceptor groups respectively, X represents O or S. These compounds exhibit high nonlinear optical activity. Also disclosed are polymers comprising such molecules.

Description

NOVEL NONLINEAR OPTICAL MOLECULES AND POLYMERS INCORPORATING THEM

BACKGROUND OF THE INVENTION This invention discloses novel organic molecules that contain fused ring rigid rod moieties possessing high nonlinear optical activity, and also polymers that contain such organic moieties in their repeat units .

Nonlinear optical activities generally result from interaction of materials with light, and are described in terms of second order nonlinearity, third order nonlinearity, and so on. An introduction to the theory and practical applications of nonlinearity, especially of organic materials, is provided by Nonlinear Optical Properties of Organic Molecules and Crystals, Volumes. 1 & 2 , edited by D. S. Chemla and J. Zyss, Academic Press, 1987.

It is known that organic small molecules and polymeric materials with large delocalized Il-electron systems can exhibit nonlinear optical response, which in many cases is a much larger response than that exhibited by inorganic materials. Examples of such organic small molecules include 2-methyl-4- nitroaniline. Examples of such polymers are described in Nonlinear Optical Properties of Organic and

Polymeric Materials, ed. D. J. Williams, ACS Symposium Series No. 233, American Chemical Society, Washington, D.C, 1983. Such materials generally contain in their nonlinear molecular units electron donor groups and acceptor groups linked by a conjugated Il-electron unit. This structural pattern gives rise to delocalization of the ϋ-electrons . The delocalized H-electrons are believed to give rise to nonlinear effects when the material interacts with high intensity monochromatic laser radiation. These effects are manifested as generation of different orders of light frequencies called harmonic frequencies.

While a nonlinear molecule can theoretically generate different orders of harmonic frequencies when it interacts with light, it is generally believed that in order to generate the even numbered harmonic frequencies such as second order, fourth order, and the like, the molecule must possess a "non-centrosymmetric" structure. The non-centrosymmetric structure must be inherent microscopically and induced macroscopically. A theoretical explanation of non-centrosymmetry and its relationship to harmonic generation can be found in Nonlinear Optical Properties of Organic and Polymeric Materials, referred to above . in addition to the possibility of electronic interactions with light, organic and polymeric materials can be modified structurally to suitably optimize properties such as mechanical stability, thermo-oxidative stability, and laser damage threshold. Laser damage threshold is an expression of the ability of a material to withstand high intensity laser radiation. The utility of a nonlinear optical material frequently is in a device where the material is subjected to high intensity laser radiation. Unless the material is capable of withstanding such radiation, the device may fail in its intended function.

Furthermore, several organic polymers can be cast as thin films by techniques well known in the ar . Thin films have the advantage of better utility than single crystals in device fabrication. Inorganic materials generally are single crystals.

Thin films of organic or polymeric materials with large second order nonlinearities in combination with silicon-based electronic circuitry have potential utilities in devices for laser modulation and deflection, information control in optical circuitry and the like. Novel processes occurring through third order nonlinearity such as degenerate four-wave mixing, whereby real-time processing of optical fields occurs, have potential utility in devices that have applications in such diverse fields as optical communications and integrated circuitry. Devices based on optical nonlinearity of materials are described in, for example, U.S. Patent Nos. 3,234,475; 3,395,329; 3,694,055; 4,428,873; 4,515,429; 4,583,818; and by P. W. Smith et al in Applied Physics Letters, 30 (6), 280 (1977) . Devices based on organic materials with conjugated electron systems are described, for example, in U.S. Patents 4,865,406 and 5,224,196. Nonlinear optical materials can be used either as small molecules in a guest-host combination or, more preferably, as a covalently linked part of organic polymers. Guest-host combinations are physical mixtures of a nonlinear small molecule and a film-forming polymer. Such mixtures have the disadvantage of insufficient loading of the nonlinear material and phase separation. In contrast to the guest-host combination, polymer systems where the nonlinear optical moiety is covalently linked to the polymer chain avoid such disadvantages and are generally referred to as nonlinear optical polymers.

Nonlinear moieties can be covalently linked to a polymer in either of two ways . They may exist as part of the main chain of the polymer or as pendant side groups, examples of which are also described in the afore-mentioned U.S. Patent 5,187,234. An illustrative side chain polymer is a polymer of Formula I, disclosed in U.S. Patent 4,865,430 and referred to as the "DANS" polymer hereafter:

Formula I

While such polymers exhibit good nonlinear optical activity, increasing sophistication of devices demands higher levels of such activity in polymers. Thus, there is a continuing interest in the preparation of novel polymers and copolymers containing nonlinear optical moieties with high activity. There is also an increased effort to develop novel nonlinear optical devices based on such polymers. Since the nonlinear optical activity of the polymers depends directly on the nonlinear optical activity of the moieties in their repeat units, there is a continuing interest to prepare novel organic molecules which possess an inherent high nonlinear optical activity. It would also be useful if such molecules can be made part of polymers as repeat units .

Accordingly, it is an object of this invention to provide novel organic molecules which exhibit high nonlinear optical response and which can be used as repeat units in polymers.

It is yet another object of this invention to provide novel nonlinear optical polymers which exhibit high nonlinear optical properties . It is a further object of this invention to provide nonlinear optical media incorporating a transparent nonlinear optical component which comprises such polymers . Other objects and advantages of the present invention shall become apparent from the accompanying description and examples .

SUMMARY OF THE INVENTION One or more of the foregoing objectives are achieved by the provision in the present invention of novel nonlinear optically active moieties. These moieties are ladder units containing electron donor and electron acceptor functionalities conjugatively linked via a fused rigid rod heterocyclic ring system. The fused heterocyclic ring system is typically a multi- ring system, such as, for example, a 5-ring system illustrated by the benzoxazinophenoxazine moiety or the benzoxazinophenothiazine moiety. The benzoxazinophenoxazine moiety is exemplified by the compounds of Formula lla, and the benzoxazinophenothiazine moiety by compounds of Formula lib, with "D" and "A" representing electron donor

(i.e., donates electrons into the ring system by π- interaction) and electron acceptor (i.e. withdraws electrons from the ring system by π-interaction) respectively, and R_x and R₂ being the same or different and being independently hydrogen, a C1-C6 alkyl, a halogen or an aryl such as a phenyl or naphthyl:

Formula lla: X=0 Formula lib: X=S Examples of the D group include, but are not limited to N- (2, 2-dimethyl-3-hydroxypropyl) ; N- (4, 4-bis- (4- acetoxyphenyl) -valeroyl; N- (5, 5-bis- (4-hydroxyphenyl) - hexyl;

-O- or R₃ is hydrogen or a Cl — C₄ alky], q is 2 — 3

Examples of the A group include, but are not limited to, N0₂, C(CN)₂, C(H) (CN), C(H) (N0₂), C(H) (CF₃) , C(H) (S0₂CH₃) and C(H) (S0₂CF₃) . These inventive moieties possess exceptionally large N.L.O. activity, as shown by their high nonlinear optical susceptibility ("β values") . The moieties are also versatile enough to form parts of the main chain of the polymer, or to form pendant side chains from a polymer chain.

The present invention also relates to formation of solid film media having an induced non-centrosymmetric structure using the polymers of the invention. The polymers of this invention have sufficient solubility in organic solvents such as halogenated hydrocarbons, ketones, esters, amides, and the like to be cast as films, using methods known to those skilled in the art, in order to obtain films with excellent transparency. The term "transparent" as employed herein refers to an optical medium which is transparent or light transmitting with respect to entering light frequencies (called fundamental frequencies) as well as created light frequencies (called harmonic frequencies) which terms are well known in the art and are explained in the afore-mentioned U.S. Patent 5,187,234, as well as in Nonlinear Optical Properties of Organic Molecules and Crystals, Volumes 1 & 2, mentioned earlier. The harmonic frequencies that are frequently used in device fabrication are the second harmonic ("frequency doubling") and third harmonic frequencies.

Due to its excellent film characteristics, harmonic generation, and very low light scattering, films made from the polymers of the invention are ideally suited for fabricating nonlinear optical devices, such as frequency doublers, optical switches, light modulators, and the like. Several other nonlinear optical devices are described in U.S. Patent No. 4,865,406.

DETAILED DESCRIPTION OF THE INVENTION The present invention discloses novel N.L.O. moieties which contain an electron donor group and an electron acceptor group conjugatively linked, asymmetrically substituted, through a fused 5-ring heterocyclic ring system such as a benzoxazinophenoxazine or benzoxazinophenothiazine, as described earlier. As one skilled in the art knows, extension of π-structure through such fused ladder-type 5-ring system and its planarity should lead to a very high π-overlap while the heteroatoms contribute to a net lowering of the excited state, thereby maximizing the polarization effects in such π-systems. However, at the same time, one also confronts the intractability of such fused ring systems. Rigid rod planar structures with a high electron density tend to pack in well defined crystalline states. The resulting Van-der Wall interactions generally inhibit solvating ability, making thereby the synthesis of, and manipulative ability with, such systems very difficult. It was therefore quite surprising that the inventive moieties were tractable enough to be polymerized, and the polymers could be formed into films. An embodiment of the present invention is described below with a typical synthesis of the 5-ring system, 3-amino-10-nitro-6, 13-dichlorotriphenodioxazine (Formula III) . However, it will be understood that such description is exemplary only and is for purposes of exposition and not for purposes of limitation. The synthetic scheme is outlined in Figure 1 :

Figure 1

In step 1, 2, 3,5, 6, -tetrachlorobenzoquinone ("chloranil") and 2-amino-5-nitrophenol were condensed under anhydrous conditions to form 7-nitro-1, 2,4- trichloro-3H-phenoxazine-3-one (Formula IV) . This compound was purified, and then reacted with 4-amino- 3-hydroxybenzoic acid to form 3-carboxy-10-nitro-6, 13- dichlorotriphenodioxazine (Formula V) . This compound was then converted to its acid chloride form (Formula VI) which had good solubility and was then reacted with sodium azide to form the carbazide (Formula VII) . VII was then converted into the isocyanate (Formula VIII) by Curtiuε transformation and then hydrolyzed to yield 3-amino-10-nitro-6, 13-dichlorotriphenodioxazine

(Formula III) . This compound showed a β value that was

3.9 times the β of 4-amino-4 ' -nitrostilbene, the N.L.O. moiety in the DANS polymer. Furthermore, compound of Formula III had a high thermal stability as shown by DSC and TGA studies.

Several variants of the compound of Formula III may also be prepared by suitable modification of the above synthetic approach or other suitable known processes . When the starting benzoquinone is not commercially available, it may be prepared by methods known in the art, or preferably by a novel method of oxidizing the appropriate hydroquinone by sulfuryl chloride, as is disclosed in copending U.S. Patent application, Serial No. , filed September, 1995. Some other 5-ring compounds that were prepared following the procedure described above for the dichloro 5 ring compound are listed in Table 1. Some of these compounds were obtained by appropriate derivatization of the amine group during the synthesis; such derivatization not only enhanced the solubility of the resulting N.L.O. moieties, but also facilitated their incorporation into polymeric systems. Indeed, several of these compounds had good solubility in organic solvents such as, aromatic hydrocarbons, esters and ketones, thus facilitating their incorporation into polymer skeletons.

Table 1

Compound Ri R₂ R₃ of Formula

IX NH₂ t-butyl OH

X COOH Cl Cl

XI COOH Br Br

XII COOH OCH(CF₃)₂ OCH(CF₃)₂

XIII COOH OCH(CF₃)₂ OH

XIV COOH t-butyl t-butyl

XV COOH t-butyl OH

XVI COOH Cl Cl

XVII C0C1 t-butyl OH

XVIII NH₂ t-butyl OH

XIX N- -(2 , 2-dimethyl-

3- -hydroxypropyl) Cl Cl

XX N- (4, 4-bis- (4- acetoxyphenyl) - valeroyl Cl Cl

XXI N- (5, 5-bis- (4- hydroxyphenyl) - hexyl Cl Cl

In another embodiment of the invention, the 5-ring N.L.O. moieties may be incorporated into polymers, either in the main chain or as pendant side chains, depending upon, among others, the nature of the moiety, polymerization conditions and any comonomer used. As an illustration, a main chain polymer was prepared by reacting a mixture of the bisphenol monomer of Formula XXI and 4, 4 ' -hexafluoroisopropylidene diphenol with triphosgene, under basic conditions. Incorporation of up to as much as 30 mole% of compound XXI into the polymer, a polycarbonate, could be demonstrated.

In another experiment, glycidyl methacrylate was polymerized by free radical polymerization, and compound V was grafted onto the resulting polyglycidyl methacrylate. Up to 5 mole% incorporation of compound III into the polyglycidyl methacrylate to yield the copolymer XXII was observed.

Formula XXII As one skilled in the art knows, several of these 5- ring compounds may also be converted into other polymer structures such as, for example, polyesters, polyurethanes, polyamides and the like. The polymers prepared according to the invention were soluble in solvents such as, for example, trifluoroacetic acid, N-methylpyrrolidinone, and 2- (2- ethoxy) -ethoxy ethanol, and thus fabricated into films. Films of the polycarbonate, for example, could be prepared from its solution in trifluroacetic acid. Such films can be converted into suitable optical media and devices by well known procedures in the art .

The following nonlimiting examples are provided in order to further illustrate the present invention.

EXAMPLES In the following Examples, g refers to grams, ml to milliliters, mmole refers to millimole, °C to degrees Celsius, and 'ambient temperature' to ranges between 20-28°C.

Example 1. Synthesis of 7-nitro-l, 2 , 4-trichloro- 3H-phenoxazine-3-one : In a 2 liter three neck round bottom flask equipped with a mechanical stirrer were placed 2-amino-5-nitro phenol (7.7 g, 0.05 mole) ,

2,3,5,6- tetrachlorobenzoquinone (12.4 g, 0.0505 mole, 1.01 eq.) and 1 liter of absolute ethanol. To this well-stirred suspension (the chloranil remained only partially soluble) was added anhydrous sodium acetate

(~8.2 g, 0.1 mole, 2 eq.) in one shot. The suspension immediately darkened to deep red without any temperature rise and micro-crystalline precipitates appeared. After stirring an additional 2 hours the product was filtered in a coarse-fritted funnel and washed with 200 ml of water, followed by an additional 300 ml of absolute ethanol. Drying in a vacuum oven at 100°C for three hours yielded 17.02 g (98.6%) , mp 235- 237°C.

Example 2. Synthesis of 3-carboxy-10-nitro-6 , 13- dichlorotriphenodioxazine: In a 3 liter 3 neck round bottom flask equipped with a reflux condenser and a mechanical stirrer were placed 7-nitro-l, 2 , 4-trichloro- 5-phenoxazine-3-one (25.5 g, 0.074 mole) , 2 liters of absolute ethanol, and 4-amino-3-hydroxybenzoic acid (13.56 g, 0.088 mole, 1.2 eq. ) . To this well stirred warming suspension was added anhydrous sodium acetate (20 g, 0.24 mole, 3.3 eq. ) in one shot and the mixture heated to reflux for 18 hours . Upon cooling the mixture was acidified with 100 ml of 3 M hydrochloric acid, stirred for an additional hour, and the product collected by suction filtration. After copious water washing and a final absolute ethanol wash, the crude acid was transferred to a soxhelet extractor and extracted with acetone for approximately 3 days . After drying the product weighed between 9 - 17 g (29%-51%) .

Example . Synthesis of 3-carboxoyl-10-nitro- 6 , 13-dichlorotriphenodioxazine chloride: In a 500 ml single neck round bottom flask equipped with a condenser and drying tube were placed 3-carboxyl-10- nitro-6, 13-dichlorotripheno-dioxazine (5.0 g, 0.011 mole) , 100 ml of toluene, and freshly distilled thionyl chloride (5 g, 0.04 mole, 3.6 eq) . The mixture was heated at reflux for 18 hrs after which it was thoroughly cooled, filtered on a fine fritted sintered funnel, and washed with toluene (approximately 50 ml) . Upon drying the product weighed 4.2 g (80%) .

Example 4. Synthesis of 3-carbazoyl-10-nitro- 6 , 13-dichlorotriphenodioxazine: In a 500 ml single neck round bottom flask fitted with a drying tube was placed 3-carboxoyl-10-nitro-6, 13- dichlorotriphenodioxazine chloride (4.2 g, 0.009 mole) and 100 ml of NMP (which had previously been dried over anhydrous sodium carbonate) . To this solution was added sodium azide (1.2 g, 2.2 eq) dissolved in a minimum amount of water:NMP (1:1 v/v) all in one shot. The mixture was allowed to stir overnight at room temperature and then it was poured into 3 liters of 20% aqueous sodium chloride solution in a large separatory funnel. The crystalline precipitate which formed slowly settled (about 12 hrs) to the bottom of the funnel facilitating a more concentrated suspension to deliver to the collection funnel. The precipitate/water suspension was then dripped onto a fine fritted funnel where the product was collected and washed several times with water. After extensive air drying the product weighed 4.2 g (essentially 100%) .

Example 5. Synthesis of 3-isocyanato-10-nitro- 6 , 13-dichlorotriphenodioxazine (the isocyanate compound of Formula VIII) : In a 500 ml round bottom flask equipped with a condenser and drying tube were placed 3-carbazoyl-10-nitro-6, 13-dichlorotripheno-dioxazine (4.2 g, 0.009 mole) , and 200 ml of toluene. This was heated up to reflux for 18 hrs and cooled. On cooling crystals of the isocyanate grew on the side of the flask and were collected by filtration. On air drying the product yielded 3.6 g (92%) .

Example 6. Synthesis of 3-amino-10-nitro-6, 13- dichlorotriphenodioxazine: In a 500 ml round bottom flask equipped with a condenser were placed 3- isocyanato-10-nitro-6, 13-dichlorotriphenodioxazine from Example 5 (1.0 g, 0.002 mole) , and 50 ml of toluene. This was heated to reflux and 50 ml of 10% sodium hydroxide solution added. An emulsion formed and there was an immediate purple/blue tinge. Heating was continued until a definite separation was seen between the layers and then the product could be isolated by a procedure involving separation and centrifugation of the aqueous layer. The product remained as a green solid in the bottom of the centrifuge tube and was isolated by standard procedures known to those skilled in the ar . Aqueous soluble impurities were then removed from the material by soxhelet extraction with water. Typical yield was 0.5 g or about 50%. (This hydrolysis could also be done by acid hydrolysis method, as shown, for example, in Example 18 below.)

Example 7. Synthesis of 2,5-di- (hexafluoroisopropoxy) -1,4-dichloro-benzoαuinone : In a 500 ml three neck flask equipped with a solid addition funnel, condenser, and drying tube was placed hexaflouroisopropanol (3.9g, 0.022 mole) in 200 ml of dry THF. Solid sodium (5.0 g, 0.05 mole) was then added slowly at a rate to provide gentle reflux. The addition funnel was then charged with chloranil (2.45 g, 0.01 mole) and the solids added over a 1 hour period. The addition of the chloranil resulted first in the appearance of a greenish solution which slowly decolorized to yellow. Upon completion of the chloranil addition the solution was refluxed for 4 hours and cooled. Any excess alkaline products were neutralized by the addition of 1% aqueous hydrochloric acid in methanol, and the precipitate was collected by filtration and washed with methanol. A pure product was obtained from recrystallization from cyclohexane (yield, 4.1 g, 78%, mp 112-114) .

Example 8. Synthesis of 7-nitro-2-chloro-1, 4- di- (hexafluoroisopropoxyl) -3H-phenoxazine-3-one : This compound was prepared in a fashion similar to that of the dichloro compound above. Crystals of the 3-ring derivative precipitated from the reaction mixture,- more was obtained from the mother liquors also. The product was recrystallized from absolute ethanol (20 ml per gram) for analysis, but the filtered product is quite pure for subsequent steps. The total yield was 4.2 g (82%, mp 181-183) . Example 9. Synthesis of 3-carboxy-10-nitro- 6 , 13-di- (hexafluoroisopropoxyl) -triphenodioxazine:

This compound was prepared similar to that of 3- carboxy-10-nitro-6, 13-dichlorotriphenodioxazine above. The yield was 90%.

Example 10. Synthesis of 3-carboxγl-10-nitro- 6, 13-di (hexaflouroisopropoxyl) -triphenodioxazine chloride and then the corresponding azide: These were prepared from the acid of Example 9 by a procedure described previously for the acid chloride and the azide, under Examples 3 and 4 above (yield 2.5 g, 87%) .

Example 11. Synthesis of 3-carboxy-10-nitro- 6 , 13-di (hexafluoroisopropoxyl) -triphenodioxazine trifluoroacetyl amide: The synthesis of the trifluoro amide was done by in-situ decomposition of the azide of Example 10 and capture of the intermediate isocyanate by trifluoroacetic acid. Thus, a suspension of 3- carboxy-10-nitro-6, 13-di (hexafluoroisopropoxyl) - triphenodioxazine azide (2.91 g, 0.005 mole) in toluene (250 ml) was heated to 50° C in a three neck 500 ml round bottom flask equipped with a condenser, drying tube and addition funnel. To the addition funnel was charged trifluoroacetic acid (2.85 g, 5 eq) which was added over a 5-minute period. On completion of the addition, the flask was brought to reflux and maintained thereat for at least 24 hours. The reaction was monitored by IR; at the midway point (12 hrs) an additional equivalent of trifluoroacetic acid was added. On formation of the amide a reddening of the product was noticed. Concentration of the reaction solution yielded the product 3.1 g (essentially 100%) which was used without further purification. Example 12. Synthesis of 3-amino-10-nitro-6 , 13- di (hexafluoroisopropoxyl) -triphenodioxazine: The hydrolysis of the above trifluoroacetamide by traditional routes yielded the desired amine.

Synthesis of 2, 5-di-t-butyl-3, 6-dichlorobenzoquinone derivatives

Example 13. Synthesis of 2 , 5-di-t-butyl-3 , 6- dichlorobenzoquinone: This compound was synthesized from 2, 5-di-t-butylbenzoquinone in 60% overall yield by the procedure described by H. W. Moore and W. Weyler, J. Amer. Chem. Soc , Vol. 93 (11) , 2812 (1971) . Since 2, 5-dibutylbenzoquinone was not available commercially it was synthesized from 2, 5-di-t-butyl-hydroquinone by oxidation with sulfuryl dichloride, as described in copending patent application, Serial No.

, filed September 1995. In a single neck 500 ml round bottom flask equipped with a reflux condenser were placed 2, 6-di-t-butyl-1, 4-hydroquinone (46.8 g, 0.210 mole) and sulfuryl dichloride (56.8 g, 33,8 ml, 2 eq) . No agitation was required. The suspension was then heated by means of an oil bath to reflux, and on heating for an additional hour the product appeared as a bright yellow-orange solid. The flask was then cooled, the solid broken up with a glass rod and the contents poured into a 1 liter Erlenmeyer flask containing 500 ml of 50% aqueous ethanol. After sufficient agitation (~1 hr stir time) the product had broken up into small granules and was filtered with suction. Upon drying in vacuo yielded 45.6 g (_>98% yield) . The product was quite pure (mp 149-152 °C) but was recrystallized from 75% aqueous ethanol to yield 37.5 g (78% overall) with a mp of 151-152°C. This was then converted to the dichloro compound as described by Moore et al , referred to above.

Example 14. Synthesis of 3-carboxy-10-nitro- 6, 13-di-t-butyltriphenodioxazine: The di-chloro-di-t- butyl quinone was converted to 3-carboxy-l0-nitro-6, 13- di-t-butyl-triphenodioxazine similar to Examples 1 and 2 in 20% yield.

Example 15. Synthesis of 3-carboxoyl-10-nitro- 6, 13-di-t-butyltriphenodioxazine chloride: In a 250 ml single neck round bottom flask equipped with a condenser and drying tube were placed 3-carboxy-10- nitro-6, 13-di-t-butyltripheno-dioxazine (1.3 g, 0.0027 mole) , 100 ml of toluene, and freshly distilled thionyl chloride (1.0 g, 0.08 mole, 3 eq.) . The mixture was heated at 110°C for 4 hours after which the solvent and excess thionyl chloride were stripped off on a roto- evaporator to yield l.l g (82%) of the acid chloride. (acid chloride C=0, 1742 cm^"1,- acid C=0, 1597 cm^"1) .

Example 16. Synthesis of 3-carbazoyl-10-nitro- 6, 13-di-butyltriphenodioxazine: This was prepared similar to the dichloro compound above. In a 100 ml single neck round bottom flask fitted with a drying tube was place 3-carboxoyl-10-nitro-6, 13-di-t- butyltriphenodioxazine chloride (1.2 g, 0.0024 mole) and 15 ml of dry N-methylpyrrolidinone ("NMP") . To this solution was added in one shot a solution of sodium azide (0.17 g, 2,2 eq) dissolved in a minimum amount of water:NMP (1:1, v/v) . The mixture was allowed to stir overnight at room temperature and then it was poured into 150 ml of water. The crystalline precipitate which formed slowly settle the product was collected and washed several times with water. After extensive air drying the product weighed 0.45 g (37%) . The disappearance of the carbonyl of the acid chloride and the characteristic infrared absorption of the acyl azide moiety provided an effective method of monitoring the progress of the reaction (acyl azide C=0, 2139 cm^"

Example 17. Synthesis of the isocyanate from the carbazide: In a 100 ml round bottom flask equipped with a condenser and drying tube were placed 3- carbazoyl-10-nitro-6, 13-di-t-butyltriphenodioxazine (0.45 g, 0.00088 mole) , and 25 ml of toluene. This was heated up to reflux for 18 hrs and the solvent stripped by roto-evaporation. Scraping the product from the flask yielded a total of 0.39 g (92%) of the desired product which showed no azide moiety by IR and possessed the distinctive isocyanate absorption (isocyanate N=C=0, 2217 cm^"1) .

Example 18. Synthesis of 3-amino-10-nitro-6 , 13- di-t-butyltriphenodioxazine: In a 500 ml round bottom flask equipped with a condenser were placed 3- isocyanato-10-nitro-6, 13-di-t-butyltriphenodioxazine (0.35 g, 0.00077 mole) , and 50 ml of concentrated hydrochloric acid. This was heated to approximately

50°C for 4 hours. (Immediately on contact with the acid there appeared a purple/blue tinge.) The resulting suspension was then cooled and filtered, after which the precipitate was suspended in 50 ml of water and then neutralized with 40% sodium hydroxide. After filtration, extensive water washings and drying, the product was isolated as a dark purple dust (0.27 g, 81%) .

Other Derivatives; Example 19. Synthesis of 3-amino-10-nitro-6 , 13- di- (hexadecylfluoro) -triphenodioxazine: Following a procedure similar to the preparation of the dichloro compound above, 2, 5-di- (hexadecylfluoro) -1, 4- dichlorobenzoquinone was prepared. This compound is converted to the triphenodioxazine compound by following steps described above.

Example 20. Synthesis of 2- (N- (2-hydroxyethyl) - N-methylamino) -3,4,6- trichlorobenzoαuinone: In a one liter single neck round bottom flask were placed 2 , 3 , 4, 6-tetrachlorobenzoquinone (chloranil) (18.45 g, 0.075 mole) , a magnetic stir bar, and 300 ml of THF. To this vigorously stirred suspension was added N-(2- hydroxyethyl) -N-methylamine (12.39 g, 13.25 ml, 2.1 eq) dropwise. The reaction was immediate, with the solution turning a dark green color and the temperature rising slightly. This solution was then stirred an additional hour and then decanted into a clean single neck 1 liter round bottom flask followed by concentration of the solution on a roto-evaporator. The crude solid was air dried and then dissolved in about 100 ml THF. Approximately 800 g of 230-400 mesh silica gel was loaded onto a chromatography column in ethyl acetate. The THF solution was loaded on this column and eluted with about 2 liters of ethyl acetate to isolate the desired product. Yield 75-80%.

Example 21. Synthesis of the 7-nitro-l- (N-2- hydroxyethyl) -N-methylamino) -2, 4-dichloro-3H- phenoxazine-3-one: This was prepared by a procedure described in Example 1 to yield 6 to 7 grams (40 to 50%) of the desired material which may be recrystallized from aqueous ethanol. This compound may be converted to the 5-ring N.L.O. active material by a procedure described earlier for the other 5-ring compounds .

Example 22. Synthesis of 4,4-bis-(4- acetoxyphenyl) -valeric acid: The synthesis of 4,4-bis- (4-acetoxyphenyl) -valeric acid was done by reacting 4, 4-dihydroxyphenyl valeric acid with acetic anhydride using sodium acetate as catalyst . Thus the dihydroxy acid was suspended in acetic anhydride (100 ml) containing sodium acetate. The mixture was brought to reflux for 2 hours, cooled, and the excess acetic acid decomposed by pouring into water. The two layers were separated and the product was dissolved in 100 ml of diethyl ether. The ether layer was washed twice with 10 percent sodium carbonate, once with water and finally with saturated sodium chloride solution followed by drying and concentration. The resulting thick oil slowly crystallized on standing to the product of high purity (yield 88 percent) .

Example 23. 4,4-bis- (4-acetoxyphenyl) -valeroyl chloride: This compound was synthesized from the above acetate by reaction with thionyl chloride in toluene followed by concentration. Thus the acetate and thionyl chloride in toluene were refluxed for 4 hours followed by work-up resulting in a low melting solid (yield essentially quantitative) . This compound was confirmed by IR as containing no carboxylic acid and was used without further purification.

Example 24. Synthesis of 3-N- (4, 4-bis- (4- acetoxyphenyl) -valeroyl) -10-nitro-6 , 13- dichlorotriphenodioxazine amide: The 4, 4-bis- (4- acetoxyphenyl) -valeroyl chloride prepared above was reacted with the 5 ring nitro-amine of Example 6 by traditional routes in THF to prepare the title compound which was recrystallized from acetonitrile.

Example 25. Synthesis of 3-N- (5 , 5-bis- (4- hydroxyphenyl) -hexyl) -10-nitro-6, 13- dichlorotriphenodioxazine amine: The amide prepared above was thoroughly dried in vacuum overnight at 50° C and placed in a pre-dried three neck 500 ml round bottom flask equipped with a nitrogen purged addition funnel and condenser with drying tube. The flask was charged with 100 ml of freshly distilled THF (from sodium) and cooled in an ice bath to 5 C. The addition funnel was then charged with required amount of lithium aluminum hydride in THF (1 M solution) and addition was carried out to keep the flask at a gentle boil. After the addition was complete, the flask was cooled and 10 ml of methanol containing 1% hydrochloric acid was slowly added. The mixture was allowed to sit for 1 hour at room temperature. Filtration gave the crude product which was purified by placing the entire precipitate in concentrated hydrochloric acid (100 ml) followed by diluting with 500 ml of water, filtering the product and washing with water until the filtrate was neutral . After drying in vacuum the product could be directly used in the following polymerization.

Example 26. Copolymerization of 3-N- (5 , 5-bis- (4-hydroxyphenyl) -hexyl) -10-nitro-6 , 13- dichlorotriphenodioxazine amine with triphosgene: The bisphenol monomer from Example 25(0.05g, 0.000075 mole) and 4, 4 ' -hexafluoroisopropylidene- diphenol ("6-F bisphenol-A") (1.23 g, 0.0037 mole) were dissolved in 10% aqueous NaOH (50ml) containing 0.01 mole % of tetrabutylammonium chloride. To this well stirred solution was added triphosgene (l.lg, 0.0038 mole) dissolved in 50 ml methylene chloride. The reaction was immediate and was stirred vigorously for 4 hours. The resulting polymer was isolated by precipitation in methanol followed by water washing until the filtrate was neutral. On drying the polymer weighed 1.2 g (80%) . This represented the incorporation of 2 mole % (4%/wt) . The polymer was soluble in trifluoroacetic acid and formed clear films on a glass substrate. Polymers with higher levels of incorporation (about 30 mole%) could also be prepared. These polymers were soluble in 2- (2-ethoxy) -ethoxy ethanol at 200° C.

Example 27. From polyglycidyl methacryalte: Polyglycidyl methacrylate was prepared first by traditional routes. The 5 ring amino-nitro compound of Example 5 was dissolved in 1:1 NMP: chlorobenzene and then reacted with the polyglycidyl methacrylate to achieve approximately 15% by weight (7 molar percentage) incorporation into the polymer.

Claims

CLAIMSWhat is claimed is :

1. nonlinear optical organic compound of the general formula:

wherein D and A represent electron donor and electron acceptor groups respectively, X represents 0 or S, and R-_L and R₂ are the same or different and are independently hydrogen, a C1-C6 alkyl, a halogen or an aryl such as a phenyl or naphthyl moiety.

2. The nonlinear optical compound of claim 1, wherein D is selected from the group consisting of N- (2,2- dimethyl-3-hydroxypropyl) ; N- (4, 4-bis- (4- acetoxyphenyl) -valeroyl; N- (5, 5-bis- (4-hydroxyphenyl) - hexyl,-

O- or -S R₃ is hydrogen or a Cl — C₄ alkyl, q is

and A is selected from the group consisting of N0₂, C(CN)₂, C(H) (CN) , C(H) (N0₂) , C(H) (CF₃) , C(H) (S0₂CH₃) and C(H) (S0_{2 (}CF₃) .

3. The nonlinear optical compound of claim 2, wherein D is an amine and A is a nitro group.

4. The nonlinear optical compound of claim 1, wherein X is 0.

5. The nonlinear optical compound of claim 3, wherein R_x and R₂ are the same and are Cl, t-butyl or OCH(CF₃)₂.

6. The nonlinear optical compound of claim 2, wherein D is N- (5, 5-bis- (4-hydroxyphenyl) -hexyl and A is N0₂.

7. A polymer which comprises, in its repeat units, the moiety with the general formula:

wherein X is 0 or S, D represents a group that donates electrons into said moiety by π-interaction, A represents a group that withdraws electrons from said moiety by π-interaction, and R_x and R are the same or different and are independently hydrogen, a C1-C6 alkyl, a halogen or an aryl such as a phenyl or naphthyl moiety.

8. The polymer of claim 7, wherein said moiety forms part of the main chain of said polymer.

9. The polymer of claim 8, which is a polycarbonate.

10. The polymer of claim 7, wherein said moiety forms part of the side chain of said polymer.

11. The polymer of claim 10, which is a vinyl polymer.

12. A transparent nonlinear optical medium comprising said polymer of claim 7.