TRICYCLIC SPACER SYSTEMS FOR NONLINEAR OPTICAL DEVICES

Abstract

A compound for spacing nonlinear optical chromophores of the Formula I

##STR00001##

and the commercially acceptable salts, solvates and hydrates thereof, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, W, X, Y, Z, Q.sup.1, Q.sup.2, Q.sup.4 and L have the definitions provided herein.

Claims

1. A compound for spacing nonlinear optical chromophores of the Formula I ##STR00017## or a commercially acceptable salt thereof; wherein R.sub.3 is a C.sub.6-C.sub.10 aryl, C.sub.6-C.sub.10 heteroaryl, 4-10 membered heterocyclic or a C.sub.6-C.sub.10 saturated cyclic group; 1 or 2 carbon atoms in the foregoing cyclic moieties are optionally substituted by an oxo (O) moiety; and the foregoing R.sup.3 groups are optionally substituted by 1 to 3 R.sup.5 groups; R.sub.1 and R.sub.2 are independently selected from the list of substituents provided in the definition of R.sub.3, (CH.sub.2).sub.t(C.sub.6-C.sub.10 aryl) or (CH.sub.2).sub.t(4-10 membered heterocyclic), t is an integer ranging from 0 to 5, and the foregoing R.sub.1 and R.sub.2 groups are optionally substituted by 1 to 3 R.sup.5 groups; R.sub.4 is independently selected from the list of substituents provided in the definition of R.sub.3, a chemical bond (), or hydrogen; each Q.sup.1, Q.sup.2, and Q.sup.4 is independently selected from hydrogen, halo, C.sub.1-C.sub.10 alkyl, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, nitro, trifluoromethyl, trifluoromethoxy, azido, OR.sup.5, NR.sup.6C(O)OR.sup.5, NR.sup.6SO.sub.2R.sup.5, SO.sub.2NR.sup.5R.sup.6, NR.sup.6C(O)R.sup.5, C(O)NR.sup.5R.sup.6, NR.sup.5R.sup.6, S(O).sub.jR.sup.7 wherein j is an integer ranging from 0 to 2, NR.sup.5(CR.sup.6R.sup.7).sub.tOR.sup.6, (CH.sub.2).sub.t(C.sub.6-C.sub.10 aryl), SO.sub.2(CH.sub.2).sub.t(C.sub.6-C.sub.10 aryl), S(CH.sub.2).sub.t(C.sub.6-C.sub.10 aryl), O(CH.sub.2).sub.t(C.sub.6-C.sub.10 aryl), (CH.sub.2).sub.t(4-10 membered heterocyclic), and (CR.sup.6R.sup.7).sub.mOR.sup.6, wherein m is an integer from 1 to 5 and t is an integer from 0 to 5; with the proviso that when R.sup.4 is hydrogen Q.sup.4 is not available; said alkyl group optionally contains 1 or 2 hetero moieties selected from O, S and N(R.sup.6) said aryl and heterocyclic Q groups are optionally fused to a C.sub.6-C.sub.10 aryl group, a C.sub.5-C.sub.8 saturated cyclic group, or a 4-10 membered heterocyclic group; 1 or 2 carbon atoms in the foregoing heterocyclic moieties are optionally substituted by an oxo (O) moiety; and the alkyl, aryl and heterocyclic moieties of the foregoing Q groups are optionally substituted by 1 to 3 substituents independently selected from nitro, trifluoromethyl, trifluoromethoxy, azido, NR.sup.6SO.sub.2R.sup.5, SO.sub.2NR.sup.5R.sup.6, NR.sup.6C(O)R.sup.5, C(O)NR.sup.5R.sup.6, NR.sup.5R.sup.6, (CR.sup.6R.sup.7).sub.mOR.sup.6 wherein m is an integer from 1 to 5, OR and the substituents listed in the definition of R.sup.5; each R.sup.5 is independently selected from H, C.sub.1-C.sub.10 alkyl, (CH.sub.2).sub.t(C.sub.6-C.sub.10 aryl), and (CH.sub.2).sub.t(4-10 membered heterocyclic), wherein t is an integer from 0 to 5; said alkyl group optionally includes 1 or 2 hetero moieties selected from O, S and N(R.sup.6) said aryl and heterocyclic R.sup.5 groups are optionally fused to a C.sub.6-C.sub.10 aryl group, a C.sub.5-C.sub.8 saturated cyclic group, or a 4-10 membered heterocyclic group; and the foregoing R.sup.5 substituents, except H, are optionally substituted by 1 to 3 substituents independently selected from nitro, trifluoromethyl, trifluoromethoxy, azido, NR.sup.6C(O)R.sup.7, C(O)NR.sup.6R.sup.7, NR.sup.6R.sup.7, hydroxy, C.sub.1-C.sub.6 alkyl, and C.sub.1-C.sub.6 alkoxy; each R.sup.6 and R.sup.7 is independently H or C.sub.1-C.sub.6 alkyl; X, Y and Z are each independently selected from C (carbon), O (oxygen), N (nitrogen), and S (sulfur), and are included within R.sup.3; X, Y, and Z are immediately adjacent to one another; W is any non-hydrogen atom in R.sup.3 that is not X, Y, or Z; and L is a labile group or a nonlinear optical chromophore; with the proviso that when the compound of Formula I has the structure: ##STR00018## wherein L represents a labile group selected from the group consisting of hydroxyl groups, alkoxy groups, nitro groups, amines and halogens, and wherein Q.sup.1 and Q.sup.2 each represent a butoxy group; Q.sup.4 is not a methoxy group.

2. The compound of claim 1 wherein R.sup.1 and R.sup.2 are [1,3,4]thiadiazol-2-yl; R3 is indole; R4 is a single chemical bond; and Q.sup.1, Q.sup.2, and Q.sup.4 are methoxy.

3. The compound of claim 2 wherein X and Y are carbon, Z is nitrogen and L is amine.

3. A compound according to claim 1 wherein the compound of Formula I is selected from the group consisting of: ##STR00019## ##STR00020##

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0040] FIG. 1 A general representation of the spacer systems of the present invention wherein the chromophore is represented as a crayon in 1A;

[0041] FIG. 2 Schematic representation of spacer system with attached chromophore core;

[0042] FIG. 3 Schematic representation of spacer system having attached Q group functionality and attached chromophore;

[0043] FIG. 4 Nonlimiting Examples of Specific Polymerizable Functionality Introduced with Reactive Alkylating Agents;

[0044] FIG. 5 Nonlimiting Examples of Specific Functionality Capable of Secondary Bonding for Applications Introduced with Reactive Alkylating Agents;

[0045] FIG. 6 Nonlimiting Examples of Specific Functionality Capable of Secondary Bonding by Condensation Polymerization Crosslinking Approaches through Block/Deblock Technology Employing the Reactive Alkylating Agents as Key Intermediates;

[0046] FIG. 7 Nonlimiting Conventional Crosslinking Agents Applicable to the Production of Crosslinked Materials;

[0047] FIG. 8 Structural illustration depicting Q group attachment on the spacer, the chromophore or a combination thereof;

[0048] FIG. 9 Conventional Process for the Production of Useful 4-Phenyl-m-Terphenyl Intermediates with Reactive Amino, Diazo, Halogen and Hydroxy Functionality;

[0049] FIG. 10 Specific Nonlimiting Examples of Introduction of Spacer 4-Phenyl-m-Terphenyl Functionality into a Novel Chromophore System with a 1-Amino-4-Phenyl-m-Terphenyl Key Intermediate;

[0050] FIG. 11 Visible Absorption Spectra of Chromophores compared to Spacer System with the 4-phenyl-m-terphenyl Spacer Function;

[0051] FIG. 12 Conventional Processes for the Production of Useful Organometallic 4-Phenyl-m-Terphenyls by Reaction with Periodic Group IA Metals with the Halogen Functionality of 1-Halo-4-Phenyl-m-Terphenyls;

[0052] FIG. 13 Conventional Processes for the Production of Useful Organometallic 4-Phenyl-m-Terphenyl Intermediates by Reaction with Periodic Group IIA Metals with the Halogen Functionality of 1-Halo-4-Phenyl-m-Terphenyls;

[0053] FIG. 14 Specific Nonlimiting Examples of Application of Conventional Block-Deblock Techniques for Q-Functionalization of methoxylated spacer 4-Phenyl-m-Terphenyl Systems;

DETAILED DESCRIPTION OF THE INVENTION

[0054] The compounds of Formula I are useful as agents for spacing nonlinear optical chromophores to prevent the chromophores from aggregating. Many useful NLO chromophores are known to those of ordinary skill in the art. While any NLO chromophore that provides the desired NLO effect and is compatible with the synthetic methods used to form the NLO spacer/chromophore may be used in the present invention, preferred NLO chromophores include an electron donating group and an electron withdrawing group.

[0055] FIG. 1 presents in a general fashion the tricyclic structure of the chromophore spacer system of the present invention. Typically, the spacer, which consists of R.sup.1, R.sup.2 and R.sup.3, is attached to a non-linear optical chromophore, L in FIG. 1, near the center of the chromophore rather than the end of the chromophore. The spacer effectively wraps around the chromophore L to create a small void space V that prevents other molecular species, including solvents, from interacting with the chromophore. Consequently, the spacer R.sup.1, R.sup.2 and R.sup.3, protects the chromophore L from physical contact and chemical attack by molecular species which may interfere with the electronic properties of the chromophore. In addition, the spacers effectively prevent the active chromophores from aggregating in the common head-to-tail pattern during processing. In certain embodiments of the present invention a fourth ring system R.sup.4 may be added to the spacer R.sup.1, R.sup.2 and R.sup.3, at the R.sup.3 position to provide additional separation between the individual chromophores. FIG. 2 illustrates a spacer system incorporating all four ring moieties R.sup.1, R.sup.2, R.sup.3, and R.sup.4.

[0056] Essential to all subject systems of this Invention is the spacer system shown in 1B individually and multiply in 1C. Shown in 1D is the essential component on a chromophore substituted with optional Q-Groups. Shown in 1E, 1F, 1G and 1H are Q-Groups that are substituted. All systems illustrated as 1B, 1C, 1D, 1E, 1F, 1G and 1H lie within the scope of this Invention for Level 1 applications.

[0057] The various cyclic moieties of the spacer R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may incorporate additional functional groups Q that add thermal stability to the spacer/chromophore system and also allow the spacer to serve as a polymeric monomer capable of being inserted into any of a number of polymer systems including polyamides, polyimides, polyesters, etc. FIG. 3 shows a terphenyl spacer with functional groups Q1, Q2 and Q4 attached to the peripheral cyclic moieties R1, R2 and R4 respectively. In one embodiment the individual Q groups may be selected from substituents that become chemically reactive during poling processes that align the chromophores, such that the individual Q groups polymerize with one another creating a nonlinear optical polymer with engineered spacing between the chromophores.

[0058] Nonlimiting examples of Q groups capable of providing polymerizable functionality to the spacer are provided in FIG. 4. The functional groups listed in FIG. 4 may be introduced to the spacer as reactive alkylating agents. Additional functional groups that serve as potential Q groups are listed in FIG. 5. The functional groups of FIG. 5 may also be introduced to the spacer as reactive alkylating agents in a block/deblock process as shown in FIG. 14. High stability methoxy blocking groups may be terminally located at various points of the spacer systems. Chemical methods well-known to those skilled in the art may be used to replace or deblock these groups with more reactive hydroxy constituents which may in turn be easily replaced with a broad variety of R-groups. Additional functionality that may serve as Q groups include the various monomers from polymer condensation reactions. FIGS. 5, 6 and 7 include nonlimiting examples of various functional groups that are known monomers that may be used as Q groups to link spacers with attached chromophores.

[0059] A nonlimiting list of potential Q groups are provide in FIGS. 4-8. The salt is reacted with an appropriate alkylating agent, RX, to introduce the desired Q-Group functionality wherein .sup.Q=.sup.OR. Such processes are well known to those skilled-in-the-art.

[0060] FIG. 8 illustrates that the Q groups can be attached to any portion of the spacer/chromophore system including R1, R2, R3, R4 and the chromophore. If reactive functional groups are placed on the R1 and R2 rings then a string of spacer/chromophore monomers can be attached in a polymeric fashion. If reactive functional groups are also attached to the R4 group crosslinking is encouraged and may be managed to some extent in the poling process. Crosslinking produces thermally stable organic optical materials. An increase in nonlinear optical properties can also be expected due to the manufacture of aligned chromophores in the poling process. The chromophores are aligned in the optimal orientation for optical activity and locked into place during the crosslinking process.

[0061] The compounds of Formula I may be prepared according to the following reaction schemes and discussions. The reaction schemes provide specific non-limiting examples of the manufacture of tricyclic spacer systems of the present invention. Each scheme demonstrates the structure common to all spacer systems of the present invention which is a central or primary cyclic structure, R.sup.3, having three atoms X, Y, and Z that are directly bonded to one another and where secondary cyclic moieties R.sup.1 and R.sup.2 are bound to atoms X and Z respectively. FIGS. 2 and 3 illustrate generically the relationship between the X, Y and Z atoms of R.sup.3 and the cyclic moieties of R.sup.1 and R.sup.2. Specific examples of the spatial relationship between R.sup.1, R.sup.2 and R.sup.3 are illustrated in schemes 1 and 2 Unless otherwise indicated, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, W, X, Y, Z, Q.sup.1, Q.sup.2, Q.sup.4, and L in the reaction scheme and discussion that follow are as defined above.

##STR00005##

[0062] With reference to scheme 1 above, a compound of Formula I may be prepared by treating a 1-phenyl-ethanone substituted by a Q group (Q.sup.1) with a benzaldehyde substituted with Q.sup.3 to provide a 1,3-diphenyl-propenone where both phenyl groups are substituted. A second 1-phenyl-ethanone with Q4 substitution is reacted with the 1,3-diphenyl-propenone to produce the 2, 4, 6 triphenyl substituted pyranyl intermediate. The pyranyl intermediate is converted to a 2-Nitro-[1,1;3,1]terphenyl with phenyl substitution at the 5 position of the central ring. Additional chemistry may be performed on the nitro functional group to provide any number of labile functional groups that will be reactive with desired binding sites on a nonlinear optical chromophore. FIG. 9 demonstrates how the terphenyl nitro can be easily converted to an amine via hydrogenation. The amine can then serve as a labile group to bond to a chromophore as depicted in FIG. 10 or as a means to make any number of labile functional groups via a diazonium intermediate as depicted in FIG. 9. Specific examples illustrated in FIG. 9 include the manufacture of hydroxyl and halo terphenyls. Halo terphenyls are particularly useful because they may serve as intermediates in the production of synthetically desirable organometallic terphenyl compounds as depicted in FIG. 12 or Grignard reagents as depicted in FIG. 13.

[0063] FIG. 11 provides a comparison of the visible absorption spectra of various functional groups attached to the same nonlinear optical chromophore (PT). The terphenyl spacer with phenyl substitution in the R.sup.4 position has the highest max at 712 nm. The spacer with the next longest max is the 1,3,5-Triisopropyl-benzene group at 672 nm. The advantage of a tricyclic system having a central cyclic structure flanked by two additional cyclic structures only one bond length from the point of attachment to the chromophore is demonstrated by the longer wavelength of the terphenyl spacer. Without being bound to any specific theory it is believed that the increased size of the spacer and the unique geometry of the tricyclic spacer system prevents interaction of the chromophore with solvent molecules thereby inducing an absorption spectrum where the higher max indicates a larger exclusion radius which preserves the optical characteristics of the chromophore. When polar aprotic solvent molecules surround the highly polar chromophore core, the solvents align in a low energy configuration to oppose the dipole of the chromophore effectively creating a localized electric field. This electric field alters the ground state CT energy of the chromophore changing its photonic absorption in a fashion known as solvatochromism. The spacer systems exclude the approach of the solvent molecules thus reducing the overall field strength.

[0064] An alternative tricyclic spacer system is depicted in Scheme 2 wherein the central R.sup.3 cyclic moiety is an indole and R.sup.1 and R.sup.2 are both phenyl groups having methoxy Q groups. R.sup.4 is a chemical bond and Q.sup.4 is methoxy.

##STR00006## ##STR00007##

[0065] The present invention is illustrated by the following Examples. It will be understood, however, that the invention is not limited by the specific details of the following Examples.

Example 1

[0066] Preparation 4-Phenyl-m-Terphenyl Functionality into a Novel Chromophore (PT) (wherein A=NO2) with a 1-Amino-4-Phenyl-m-Terphenyl Key Intermediate.

##STR00008## ##STR00009##

Example 2

[0067] Preparation of 1,3-Bis-(4-methoxy-biphenyl-4-yl)-5-(4-methoxy-phenyl)-1H-indole Spacer with Attached Chromophore (PT) wherein A=NO.sub.2.

##STR00010## ##STR00011## ##STR00012##

Example 3

[0068] Specific Nonlimiting Conventional Synthetic Scheme for the Production of a Spacer system wherein the R.sub.3 Ring System is the Heterocyclic Indole Nucleus with a 5-Methoxy Substituent and wherein the R.sub.1 and R.sub.2 are Respectively the Hereocyclic 2-(1,3,4-Thiadiazole) Nucleus with a 5-Methoxy Substituent and a 4-Anisyl Substituents.

##STR00013## ##STR00014##

Example 4

[0069] Specific Nonlimiting Conventional Synthetic Scheme for the Production of a Spacer system wherein the R.sub.3 Ring System is the Heterocyclic Indole Nucleus with a 5-Methoxy Substituent and wherein the R.sub.1 and R.sub.2 are the Hereocyclic 2-(1,3,4-Thiadiazole) Nuclei.

##STR00015## ##STR00016##

[0070] While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.