JP2004043340A - Urethane compound and organic photorefractive material using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a urethane compound which can be produced by a simple production method, is liquid, and gives organic photorefractive materials which have excellent photorefractive characteristics and have high moldability without using a plasticizer. <P>SOLUTION: The urethane compound is represented by the formula (I): A-R<SB>1</SB>-OCONH-G-NHCOO-R<SB>2</SB>-P (I) (G is a divalent aromatic ring or alicyclic type organic group; A is a non-linear optical function group; P is a photocarrier-generating, transporting function group; R<SB>1</SB>and R<SB>2</SB>are each independently a 2 to 12C alkylene). The organic photorefractive material uses the urethane compound. <P>COPYRIGHT: (C)2004,JPO

Description

のいずれかであるのが好ましい。
【００２３】
また、Ａ（非線形光学機能団）は、
【化６】

（式中、ｎは０〜１０の整数を意味する。）
のいずれかであるのが好ましい。
【００２４】
また、芳香族環又は脂環式の二価の有機基であるＧとしては、下記（８）〜（１３）が挙げられる。
【化７】

（式中、ｍは１〜４の整数を意味する。）
【００２５】
本発明の化合物のうち、特に好ましい化合物の例としては、下式（１４）：
【化８】

で表される非対称反応性ジイソシアナート化合物より誘導されるウレタン化合物などが挙げられる。
【００２６】
（本発明ウレタン化合物の製造法）
つぎに、前記式（Ｉ）の化合物の製造法について説明する。式（Ｉ）の化合物の代表的な製造法によれば、２つのイソシアナート基（好ましくは反応性の異なる：非対称反応性）を有するジイソシアナート化合物▲１▼を用いて、このイソシアナート基に対し高い反応性を有する水酸基含有のカルバゾール誘導体など光キャリア発生・輸送機能分子▲２▼と、水酸基含有のジシアノビニルアニリン誘導体などの非線形光学機能分子▲３▼とを反応させる。
【００２７】
▲１▼　ジイソシアナート化合物
本発明化合物の製造に用いることのできる前記ジイソシアナート化合物の代表的なものとしては、４−イソシアナトベンジルイソシアナートのほか、４−（２−イソシアナト）エチルフェニルイソシアナート、４−（３−イソシアナト）プロピルフェニルイソシアナート、４−（４−イソシアナト）ブチルフェニルイソシアナート、３−イソシアナトメチルフェニルイソシアナート、３−（２−イソシアナト）エチルフェニルイソシアナート、３−（３−イソシアナト）プロピルフェニルイソシアナート、３−（４−イソシアナト）ブチルフェニルイソシアナート、２−イソシアナトメチルフェニルイソシアナート、２−（２−イソシアナト）エチルフェニルイソシアナート、２−（３−イソシアナト）プロピルフェニルイソシアナート、２−（４−イソシアナト）ブチルフェニルイソシアナートなど、分子内に芳香族及び脂肪族イソシアナート基を有する非対称反応性のジイソシアナートが挙げられる。
【００２８】
また、４−イソシアナトメチル−１−メチルシクロヘキシルイソシアナート、３−イソシアナトメチル−１−メチルシクロヘキシルイソシアナート、２−イソシアナトメチル−１−メチルシクロヘキシルイソシアナートなど、２つのイソシアナート基に隣接する置換基の立体障害により非対称性を生ずるジイソシアナート化合物であってもよい（Ｈ．Ｗ．Ｉ．　Ｐｅｅｒｌｉｎｇｓ　ｅｔ．　ａｌ．，　Ｊ．　Ｐｏｌｙｍ．　Ｓｃｉ．：　Ｐａｒｔ　Ａ：　Ｐｏｌｙｍ．　Ｃｈｅｍ．　３９，　３１１２　（２００１））。
【００２９】
本発明にて特に好ましいイソシアナート化合物の構造式を下記に示す。
【化９】

（式中、ｍは１〜４の整数を意味する）
【００３０】
本発明において原料ジイソシアナート化合物として、イソシアナート基の反応性が異なるものを用いると、合成過程において中間体単離などの煩雑な操作を行うことなく目的物が得られる。また、この化合物は低分子化合物でありながら結晶性が低く、ガラス状の透明薄膜が形成可能であって成形加工性にも優れる。
【００３１】
なお、ジイソシアナートは、芳香族炭化水素に結合したイソシアナート基（芳香族イソシアナート基）と脂肪族炭化水素に結合したイソシアナート基（脂肪族イソシアナート基）とを一分子内に有し、それぞれのイソシアナート基は置換基効果によって異なる反応性を有する。すなわち、芳香族イソシアナート基に対する水酸基の求核付加反応性（ウレタン化反応）は、反応条件を選択すると、芳香族炭化水素の電子吸引性に伴って、脂肪族イソシアナート基の１００〜３００倍を示す。このような反応性の差異により先に芳香族イソシアナート基に一方の機能を有する化合物を結合し、その後、他方の機能を有する化合物を脂肪族イソシアナート基と結合させ、中間体の単離操作などを行うことなく簡便に分子内に異なる機能団を導入できる。
【００３２】
▲２▼　光キャリア発生・輸送機能分子
本発明化合物の典型的な製造法では、前記ジイソシアナート化合物▲１▼の１つのイソシアナート基と、水酸基含有の光キャリア発生・輸送機能分子▲２▼が反応する。かかる光キャリア発生・輸送機能分子の好ましいものとしては、長鎖アルキル基の一端に光キャリア発生・輸送機能団を有し、他端にイソシアナートと反応可能な水酸基を有する化合物が挙げられる。
上記▲２▼は光キャリア発生・輸送機能団と長鎖アルキルアルコールを反応して得ることができる。
【００３３】
（イ）上記光キャリア発生・輸送機能団としては、カルバゾール、４−アミノフェニル−ジフェニルアミン、トリス（４−アミノフェニル）アミン、４−アミノ−ベンズアルデヒド−Ｎ，Ｎ−ジフェニルヒドラゾンなど、１級又は２級アミノ基を有する下記（１ａ〜４ａ）の化合物が挙げられる。
【００３４】
【化１０】

【００３５】
（ロ）上記光キャリア発生・輸送機能団と反応する長鎖アルキルアルコールとしては、１１−ヒドロキシウンデシルブロマイドのほか、２−クロロエタノール、４−クロロブタノール、５−ブロモペンタノール、６−ブロモヘキサノール、８−ブロモオクタノールなどであってよく、またこれらの化合物から誘導したものでよい。
【００３６】
（ハ）そして、光キャリア発生・輸送機能分子として特に好ましいものは、Ｎ−（１１−ヒドロキシ）ウンデシルカルバゾールなど、長鎖アルキル基の一端に光キャリア発生・輸送機能団であるカルバゾール基を有し、他端に水酸基を有する化合物が挙げられる。この化合物は１１−ヒドロキシウンデシルブロマイドとカルバゾールを用い、カルバゾール中アミノ基による１１−ヒドロキシウンデシルブロマイド中ブロモメチル基に対する求核置換反応により製造される。
【００３７】
求核置換反応による製造法としては、上記光キャリア・発生機能団と上記長鎖アルキルアルコールを溶媒などに溶解して塩基性条件下に過熱・攪拌するなど、一般的に知られるアミノ基のアルキル化反応条件を選択すればよい。具体的には、Ｎ，Ｎ−ジメチルホルムアミドなどの高極性溶媒に基質を溶解させ、水酸化カリウムや炭酸カリウムなどの塩基性化合物を加える方法や、トルエンなどの低極性溶媒に基質を溶解させ、水酸化ナトリウム水溶液を加えた２相系での反応条件を適宜選択することができる。
【００３８】
▲３▼　非線形光学機能分子
他方のイソシアナート基と反応する非線形光学機能分子の代表的なものとしては、長鎖アルキル基の一端に非線形光学機能団を有し、他端にイソシアナートと反応する水酸基を有する化合物が挙げられる。
上記▲３▼は非線形光学機能団と長鎖アルキルアルコールを反応して得ることができる。
【００３９】
（イ）上記非線形光学機能団としては、Ｎ−メチル−４−ジシアノビニルアニリン、Ｎ−エチル−４−ジシアノビニルアニリン、Ｎ−プロピル−４−ジシアノビニルアニリン、Ｎ−ブチル−４−ジシアノビニルアニリン、Ｎ−エチル−２−ジシアノビニルアニリン、Ｎ−プロピル−２−ジシアノビニルアニリン、Ｎ−ブチル−２−ジシアノビニルアニリンなどのＮ−アルキルジシアノアニリン類であってよく、また、ディスパースレッド１やディスパースオレンジ３などのアミノ基含有アゾ系色素化合物を用いることができ、特に下式（５ａ）〜（７ａ）の化合物が好ましい。
【００４０】
【化１１】

（式中、ｎは前記に同じ）
【００４１】
（ロ）上記非線形光学機能団と反応する長鎖アルキルアルコールとしては、前記の光キャリア発生・輸送機能分子において用いたものをいずれも用いてよい。
【００４２】
（ハ）そして、非線形光学機能分子として好ましいものは、Ｎ−（５−ヒドロキシ）ペンチル−Ｎ−エチル−４−ジシアノビニルアニリンなど、長鎖アルキル基の一端に非線形光学機能団である４−ジシアノビニルアニリン基などを有し、他端にイソシアナートと結合する水酸基を有するものが挙げられる。かかる化合物を製造するには、Ｎ−エチル−４−ホルミルベンゼンと５−ブロモペンタノールを用い、Ｎ−エチル−４−ホルミルベンゼン中アミノ基による５−ブロモペンタノール中ブロモメチル基に対する求核置換反応を行う。
【００４３】
求核置換反応による製造法は前記同条件でよい。また、５−ブロモペンタノールをそのまま用いる場合には、後述のジシアノマロン酸縮合において合成操作が煩雑化して収率低下を招くおそれがあるので、５−ブロモペンタノールの代わりに、水酸基を保護した化合物すなわち合成等価体を用いることも可能である。ここで合成等価体としては、５−ブロモペンタノールの水酸基を無水酢酸と反応させて得られる１−アセトキシ−５−ブロモペンタンなどがある。この合成等価体は、そのまま上記求核反応に適用可能であり、この後、アセトキシ基を加水分解することにより、目的物を高収率で得ることが可能である。合成等価体を用いるかどうかは、収率や反応効率に応じて適宜使い分けることができる。ついで、この中間体のアルデヒド基とジシアノマロン酸を縮合する。
【００４４】
（第１段：芳香族イソシアナート基に対する反応）
つぎに、前記ジイソシアナート化合物と、２種の水酸基含有化合物（光キャリア発生・輸送機能分子、非線形光学機能分子）との反応操作についてより具体的に説明する。この場合、より反応性の高い芳香族イソシアナート基を先に一方の水酸基含有化合物と反応させ、つぎに他方の水酸基含有化合物を反応性の低い脂肪族イソシアナート基と反応させる逐次的な反応条件を選択する。
【００４５】
具体的には、反応初期にジイソシアナート化合物のイソシアナート基に対し等モル量の水酸基含有化合物を加える。添加は滴下や粉末添加等の方法によりゆっくりと行い、水酸基含有化合物に対するジイソシアナート化合物の量を常に過剰となるよう維持する。このようにして、ジイソシアナート化合物中の各イソシアナート基に対する水酸基含有化合物の反応選択性を高くし、逐次的反応を可能とする。
【００４６】
反応初期の反応選択性を高くするには、反応温度を可能な限り低くし、ゆっくりと反応を行ってもよい。ただし反応温度が低すぎると反応効率が低下し、ウレタン結合生成時に競合するイソシアネート三量化反応などの副反応も進行しやすくなる。したがって、反応温度は−１０〜３０℃が好ましく、特に０℃程度で水酸基含有化合物を加えることが好ましい。
【００４７】
反応に用いる溶媒としては、シクロヘキサン、ペンタン、ヘキサン等の脂肪族炭化水素類；ベンゼン、トルエン、クロロベンゼン等の芳香族炭化水素類；ＴＨＦ（テトラヒドロフラン）、ジエチルエーテル、エチレングリコールジエチルエーテル等のエーテル類；アセトン、メチルエチルケトン、４−メチル−２−ペンタノン等のケトン類；プロピオン酸メチル、酢酸エチル、酢酸ブチル等のエステル類などの低極性溶媒が好ましい。その後、反応完結のため、そのまま高極性溶媒を追加するか、別法として低極性溶媒を留去などにより除去した後、高極性溶媒を加えてもよい。低極性溶媒としては反応操作性やモノマー基質溶解性を考慮するＴＨＦなどのエーテル類が特に好ましい。
反応選択性向上のため、反応中のモノマー基質濃度は低いのが好ましいが、反応効率、及び反応操作を考慮すると、モノマー基質が０．１〜０．３ｍｏｌ／ｌとなるように溶媒を用いるのが好ましい。
【００４８】
触媒としては、効率的なウレタン結合生成のためＮ，Ｎ，Ｎ’，Ｎ’−テトラメチル−１，３−ブタンジアミン、トリエチルアミン、トリブチルアミンなどの三級アルキルアミン類；１，４−ジアザビシクロ［２．２．２］オクタン、１　，８−ジアザビシクロ［５．４．０］ウンデカ−７−エンなどの縮環アミン類；ジブチルスズジラウリン酸エステル（ＤＢＴＬ）、テトラブチルスズ、トリブチルスズ酢酸エステルなどのアルキルスズ類が用いられる。これらのうち、アルキルスズ類及び縮環アミン類は、アルキルアミン類に比べウレタン結合生成反応に対して活性の高い触媒である（Ｆ．Ｈｏｓｔｅｔｔｌｅｒ　ａｎｄ　Ｅ．Ｆ．Ｃｏｘ，　Ｉｎｄ．Ｅｎｇ．Ｃｈｅｍ．，５２，６０９−６１０，　（１９６０））。
【００４９】
これら触媒の使用にあたっては、反応初期の反応選択性を低くするためトリアルキルアミンを用いるのが好ましく、この後、活性の高い触媒を用いて効率よく反応を行うのが好ましい。前記トリアルキルアミン類の触媒量は、反応選択性、反応効率、反応操作を考慮し、モノマー基質に対し１〜３０ｍｏｌ％になるよう用いるのが好ましい。
【００５０】
（第２段：脂肪族イソシアナート基の反応）
こうして高反応性の芳香族イソシアナート基と、水酸基含有化合物である光キャリア発生・輸送機能分子と非線形光学機能分子のどちらかとの反応を行った後、脂肪族イソシアナート基と他方の水酸基含有化合物との反応を行い目的物を得る。
【００５１】
この工程では反応を効率よく行う必要があり、溶媒は基質溶解性の高いものが好ましい。反応の初段階において中間体の沈殿などが生じるようであれば、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−メチルピロリドンなどの高極性溶媒を追加する。また、反応初段階に用いた低極性溶媒を留去後、これらの高極性溶媒を加えてもよい。溶媒量は、基質濃度１０〜３０ｍｏｌ％となるように調製するのが好ましい。かかる濃度は高いほど反応は速やかに進行するが、高すぎるとビゥレット結合やイソシアヌレート結合などにより副生成物を生じる恐れがある。
触媒量は基質に対し０．１〜１０ｍｏｌ％であるのが好ましい。触媒量がこれより多いと前記の副反応が優先する可能性がある。反応速度を高くするには前記ＤＢＴＬなどの有機スズ系触媒が好ましい。
【００５２】
前記反応条件により、例えば４−イソシアナトメチルフェニルイソシアナートに対して、まず光キャリア発生・輸送機能分子としてのＮ−（１１−ヒドロキシ）ウンデシルカルバゾール、ついで非線形光学機能分子としてのＮ−（５−ヒドロキシ）ペンチル−Ｎ−エチル−ジシアノビニルアニリンを反応させて目的物（単離収率５６％）を得た。この化合物は溶媒に溶かし室温で放置すると結晶化して不透明な固体として析出する（融点Ｔｍ：９０℃）が、融点以上に加熱溶融した後急冷するとガラス転移点（Ｔｇ）２４℃の非晶質固体となった。すなわち、この化合物は熱処理して過冷却液体とすることにより結晶化が妨げられガラス状固体となり、フォトリフラクティブ材料として用いることが可能である。また、この化合物のガラス転移温度は室温以下であるので、可塑剤等を配合せずに室温付近においても分子配向効果（オリエンテーションエンハスメント効果）を得ることが可能であり、流動性が高く成形加工性も良好である。
【００５３】
（フォトリフラクティブ材料の調製）
つぎに、本発明の化合物を用いてフォトリフラクティブ材料を調製し、その特性を検討した。本発明の化合物は、そのままでもフォトリフラクティブ材料として使用し得るが、光照射エネルギーの利用効率向上のため、予め増感剤を配合するのが好ましい。
【００５４】
このような増感剤としては、フラーレン（Ｃ_６０）及びＣ_７０の類縁体、２，４，７−トリニトロフルオレノン、２，４，７−トリニトロ−９−フルオレニリデンマロニトリルなどが好ましい。増感剤の使用量は適宜調整してよいが、式（Ｉ）の化合物１００重量部に対して０．０１〜１重量部が好ましい。増感剤の使用量がこれより少ないとその効果が充分でなく、一方、これより多いと混合物の析出や絶縁破壊を招く恐れなどがある。
【００５５】
フォトリフラクティブ材料の調製にあたっては、成分を均一に混合することが必要であり有機溶媒に溶かして均一にした後混合するか、固体のまま混合して熱溶融し均一とするなど、目的に応じた方法が適宜採用されてよい。
【００５６】
（フォトリフラクティブ効果の評価方法）
本発明にて得られた有機材料のフォトリフラクティブ効果を評価するには、電圧を加えてコヒーレント光の照射を行った。すなわち、前記材料をインジウム酸化チタン（ＩＴＯ）電極がコートされた２枚の電極ガラス板にスペーサーと共に挟み込み、加熱、減圧処理して材料中の微少気泡などを除去し評価に供した。
【００５７】
評価は前記回折効率、ゲイン定数、応答速度について行った。なお、空間電場の形成を促進するため、前記評価用試料のガラス端部のＩＴＯ電極にリード線を取り付け、直流電圧を加えた測定も行った。回折効率の測定は、縮退４光波混合法により、ヘリウム−ネオンレーザーをコヒーレント光光源とし、ｓ−偏光書き込み、ｐ偏光読み出しによって行った。得られた回折光強度と透過光強度比から回折効率を求めた。また応答速度は先の回折効率測定の際、時間に対して回折効率が増大する測定結果をもとに下記の数式１により求めた。
【００５８】
【数１】

（式中、ｔは測定経過時間（秒）であり、Ｉ（ｔ）は経過時間（ｔ）における回折光強度、（∞）は飽和回折光強度である。）
【００５９】
ゲイン定数測定は、２光波混合測定により行い、ｓ偏光書き込みにより行った。得られたビーム強度をもとに下記の数式２により実際のゲイン定数を求めた（堤直人、高分子加工、４８，２０（２０００））。
【００６０】
【数２】

（式中、Ｌは相互作用長であり、γは出力される２つの光束の強度比である。）
【００６１】
【実施例】
つぎに本発明を実施例に基づきさらに具体的に説明する。
［実施例１］
（ａ）非線形光学機能分子の合成
Ｎ−エチルアニリン１６ｍｌ、１−アセトキシ−５−ブロモペンタン２０ｍｌ（１１９．６ｍｍｏｌ）、トリエチルアミン２０ｍｌをトルエン１２５ｍｌに加えて１２０℃で１９時間攪拌した。反応混合物に含まれる沈殿物を濾別後、低沸点生成物を留去し、さらにカラムクロマトグラフィーで精製して、Ｎ−エチル−Ｎ−（５−アセチルオキシ）ペンチルアニリン１４．８ｇを得た。収率５０％
【００６２】
次に無水ジメチルホルムアミドに氷冷下、オキシ塩化リン５．８ｍｌを加えて３０分攪拌し室温にした後、前記のＮ−エチル−Ｎ−（５−アセチルオキシ）ペンチルアニリン１３．９ｇ（５５．５ｍｍｏｌ）を加え、９０℃で２０時間攪拌した。反応溶液に水６００ｍｌを注ぎ、エーテル、クロロホルムの順で抽出した。有機層を無水硫酸マグネシウムで乾燥後、溶媒を留去して得た反応混合物をカラムクロマトグラフィーで精製して、Ｎ−エチル−Ｎ−（５−アセチルオキシ）ペンチル−４−ホルミルアニリン１１．８ｇを得た。収率７７％。
【００６３】
最後にジシアノマロン酸３．３ｇ（５０ｍｍｏｌ）、前記Ｎ−エチル−Ｎ−（５−アセチルオキシ）ペンチル−４−ホルミルアニリン１０．８ｇ（４５．６ｍｍｏｌ）、Ｎ，Ｎ−ジメチルアミノピリジン０．７ｇ（４．３ｍｍｏｌ）をイソプロパール６０ｍｌに加え、４０℃で３日間攪拌した。溶媒を留去して得られる反応混合物をエーテルに加え、水で洗浄した。有機層硫酸マグネシウムで乾燥後、溶媒を留去し、さらにカラムクロマトグラフィーで精製することにより、非線形光学機能分子であるＮ−（５−ヒドロキシ）ペンチル−Ｎ−エチル−４−ジシアノビニルアニリン１２．５ｇ得た。収率６７％。
【００６４】
（ｂ）光キャリア発生・輸送機能分子の合成
１１−ヒドロキシウンデシルブロマイド２０．６ｇ（８２．０ｍｍｏｌ）、カルバゾール９．２ｇ（５５ｍｍｏｌ）、トリエチルベンジルアンモニウムクロライド０．４ｇ（１．７ｍｍｏｌ）と水酸化ナトリウム１０ｇをアセトン５０ｍｌに加えて室温で１２時間攪拌した。反応溶液をろ過して不溶物を除去し、溶媒を留去して反応混合物を得た。この反応混合物に水を加え、さらに濃塩酸を任意量加えて酸性水溶液とした後、酢酸エチルで抽出した。抽出した有機層を炭酸水素ナトリウム水溶液、水、飽和食塩水の順で洗浄して、硫酸マグネシウムで乾燥した。溶媒を留去し、得られた反応混合物をカラムクロマトグラフィーで精製し、光キャリア発生・輸送機能分子であるＮ−（１１−ヒドロキシ）ウンデシルカルバゾールを得た。収量１７．０ｇ（収率９０％）。
【００６５】
（ｃ）フォトリフラクティブ材料の製造
非対称反応性ジイソシアナートである４−イソシアナトベンジルイソシアナート０．４９ｇ（２．８ｍｍｏｌ）に、前記（ａ）のＮ−（５−ヒドロキシ）ペンチル−Ｎ−エチル−４−ジシアノビニルアニリン０．７８ｇ（２．８ｍｍｏｌ）、トリエチルアミン０．０３ｇ（０．３ｍｍｏｌ）のＴＨＦ溶液（５０ｍｌ）を氷冷下に１時間かけて加え、さらに３０℃で１９時間攪拌した。つぎに、前記（ｂ）のＮ−（１１−ヒドロキシ）ウンデシルカルバゾール０．９５ｇ（２．８ｍｍｏｌ）とジブチルスズジラウリン酸エステル０．０２ｇ（０．０４ｍｍｏｌ）を加えて加熱還流しながら１９時間攪拌した。溶媒を留去して得られる反応混合物をカラムクロマトグラフィーで精製し目的物を得た。収量１．３０ｇ（収率５９％）。
【００６６】
得られた化合物が目的化合物であることを^１Ｈ−ＮＭＲ（図１）、^１３Ｃ−ＮＭＲ（図２）及び元素分析により確認した。また、示差走査熱分析（ＤＳＣ）により、この化合物はガラス転移温度２４℃の非晶質固体であることを確認した（図３）。
【００６７】
^１Ｈ−ＮＭＲ（ＤＭＳＯ−ｄ_６）　δ　ｉｎ　ｐｐｍ：１．０９−１．７４（ｍ，−ＣＨ_２−Ｎ−ＣＨ_２−ＣＨ _３ ，−ＣＨ_２−（ ＣＨ _２ ） _９ −ＣＨ_２−，−ＣＨ_２−（ ＣＨ _２ ） _３ −ＣＨ_２−，２７Ｈ）、３．３０−３．４９（ｍ，−ＣＨ _２ −Ｎ−ＣＨ _２ −ＣＨ_３，４Ｈ）、３．９２（ｔ，Ｊ＝６．４Ｈｚ，−ＣＨ_２−Ｃａｒｂａｚｏｌｅ）、４．０５−４．０９（ｍ，４Ｈ，−ＣＨ_２−Ｏ−）４．３６（ｔ，Ｊ＝６．４Ｈｚ，−ＣＨ _２ −Ｃ_６Ｈ_４）、６．８２−８．１４（ｍ，　Ｃ_６Ｈ_４，　＝ＣＨ−，−ＣＨ_２−ＮＨ−ＣＯ_２−，１８Ｈ）、９．５４（ｂｒ，−Ｃ_６Ｈ_４−ＮＨ−ＣＯ_２−，１Ｈ）
【００６８】
^１３Ｃ−ＮＭＲ（ＤＭＳＯ−ｄ_６）　δ　ｉｎ　ｐｐｍ：１２．１，　２２．７，　２５．３，　２６．５，　２６．６，　２８．４，　２８．５，　２８．６，　２８．７，　２８．８，　２８．９，　４２．１，　４３．３，　４４．７，　６３．７，　６３．９，　６８．０，　１０９．１，　１１１．６，　１１５．６，　１１６．４，　１１８．０，　１１８．４，　１１８．６，　１２０．２，　１２２．０，　１２５．６，　１２７．４，　１３３．８，　１３３．９，　１３７．９，　１３９．９，１５２．５，　１５３．６，　１５６．５，　１５８．５
【００６９】

【００７０】
（有機フォトリフラクティブ材料の製造）
このようにして得られた化合物よりフォトリフラクティブ材料の調製をつぎのように調製した。すなわち、前記（Ｃ）にて得られた化合物０．３０ｇに対し、増感剤としてフラーレン０．００１５ｇをテトラヒドロフラン５ｍｌに加えた。超音波により基質の溶解並びにフラーレンの微分散化を行った後、濾過して溶液中の不純物を除去した。溶媒を留去し、減圧乾燥処理をして所望のフォトリフラクティブ材料を得た。
【００７１】
得られた材料のフォトリフラクティブ効果を確認するため測定評価用試料を作成した。すなわち前記材料とスペーサー（１００μｍ厚のテフロン（登録商標）シート）をＩＴＯ電極付きガラス板に置き、さらにＩＴＯ電極が対向するよう、もう一枚のＩＴＯ電極付きガラス板で挟んで測定評価試料とした。
【００７２】
回折効率は縮退４光波混合法により測定した。具体的には上記試料をチルト角６０°に設置，空間電界形成を促すためにＩＴＯ電極に直流電圧を加えて測定した。光源としてはヘリウムネオンレーザーを用い、同光源を２分割後、入射角１９°でｓ偏光の干渉光を照射した。これに同光源から取り出したｐ偏光を読み出し光として照射し、回折光強度を測定した。その結果、直流電圧が７０Ｖ／μｍ時に回折効率は１５％に達することがわかった。またこのとき書き込み光照射開始から回折効率が１５％に達するまで回折光強度変化追跡により応答速度は８秒であることがわかった。
【００７３】
ゲイン定数は上記同様の条件下、ｐ偏光を書き込み光として照射したところ２つの光束間でのエネルギー移動が認められ、ゲイン定数は８ｃｍ^−１であることがわかった。このように本発明の材料は高いフォトリフラクティブ効果が得られることがわかった。
【００７４】
【発明の効果】
本発明の光キャリア発生化合物は製造法が簡便で液状を呈し、可塑剤を用いることなくフォトリフラクティブ材料が得られる。このフォトリフラクティブ材料は、従来のものに比べて優れたフォトリフラクティブ特性を有し、高い成形加工性を有する。本発明の材料は、光通信、光情報処理分野において優れた空間光変調素子を提供し得る。
【図面の簡単な説明】
【図１】実施例１にて得られた化合物の^１Ｈ−ＮＭＲスペクトルである。
【図２】実施例１にて得られた化合物の^１３Ｃ−ＮＭＲスペクトルである。
【図３】実施例１にて得られた化合物の示差走査熱分析（ＤＳＣ）による測定結果である。[0001]
The present invention relates to a novel urethane compound having two types of functional groups, a photocarrier generation / transport functional group and a nonlinear optical functional group, in the same molecule. This compound has a photorefractive effect, and can be used for a light modulation element that performs non-linear signal processing on signal light, such as light amplification, light switching, or generation of phase conjugation, by adding a sensitizer.
[0002]
As the starting diisocyanate compound of the compound of the present invention, those having a difference in reactivity between two isocyanate groups are preferable. If the reactivity of the isocyanate group is different, different functional groups can be easily introduced into the same molecule at a high yield, and the compound obtained by the asymmetric structure of the isocyanate group has an amorphous property. Easy to have.
[0003]
The compound of the present invention has a functional site necessary for the expression of photorefractive properties in the molecule in advance and is an amorphous material, so that a photorefractive material can be easily prepared.
[0004]
[Prior art]
The photorefractive effect is a phenomenon in which the refractive index of a substance changes due to an electro-optic effect caused by a spatial electric field. That is, when light irradiation is performed on a specific substance, electrons or holes (hereinafter, referred to as photocarriers) generated in the substance move, are captured by a trap center, and form a spatial electric field in the substance. It is considered that the refractive index changes due to the primary electro-optic effect caused by the spatial electric field generated here.
[0005]
In addition, when the conductivity of the material itself is low, the formation of a space electric field is promoted by applying a voltage from the outside. The details of the mechanism of the generation and movement of the photocarriers and the capture at the trap center are unknown, but the generation of the photocarriers is carried out directly from the photocarrier generation compound or from the photocarrier generation compound and the sensitizer. It is thought that it is formed from the complex formed. It is considered that carrier movement is caused by the hopping mechanism (on-sagger mechanism) using the compound as a medium. Further, it is considered that the trap center is caused by the presence of materials having different ionization potentials such as structural defects and impurities in the substance in addition to the compound (WE Moerner et al. Al. Chem. Mater. 11, 1784-1791 (1999)).
[0006]
When a substance exhibiting such a photorefractive effect is irradiated with a coherent (coherent) two-beam light beam, for example, instead of a single light beam with a uniform intensity, the light is distributed according to the spatial distribution of the light intensity of the coherent light beam. An optical carrier concentration distribution is formed, and the refractive index of the substance changes periodically in response to this, so that a so-called refractive index grating is formed. In such a refractive index grating, energy transfer occurs between two light beams because the light intensity distribution of the irradiation interference light (and the spatial electric field formed by the light intensity distribution) and the phase of the periodic change in the refractive index are different. .
[0007]
Therefore, by utilizing such characteristics, the photorefractive material is expected to be used for an optical modulation element that performs nonlinear signal processing on signal light, such as hologram recording, optical switching, and phase conjugate mirror.
[0008]
As a figure of merit for evaluating the photorefractive effect, diffraction efficiency, gain constant (or gain coefficient), response speed, and the like are used. The diffraction efficiency indicates the ratio of the intensity of light transmitted and diffracted when a light beam enters the refractive index grating. The gain constant indicates the rate of energy transfer between two light beams. The response speed indicates the speed from the incidence of light to the formation of the refractive index grating, and is considered to be a value affected by the photocarrier generation speed, the same movement speed, and the speed of the electro-optic response.
[0009]
In order to obtain such a photorefractive material, at least two functions are required: a function of generating and transporting photocarriers, and a nonlinear optical function capable of electro-optical response. In addition, since light scattering and the like cause deterioration of photorefractive characteristics, high transparency is required for the photorefractive material. Further, the photorefractive material needs to have various forms in the above-mentioned application, and excellent moldability is required.
[0010]
For example, lithium niobate and barium titanate, which are inorganic materials, are highly transparent materials, exhibit photocarrier generation ability by adding impurities (dopants), and provide a photorefractive effect. However, these inorganic compounds are single crystals and are hard and brittle, so that they have poor moldability. Furthermore, there is a problem that the above-mentioned dopant treatment and single crystal growth operation are complicated, and it is not easy to put the photorefractive material into practical use.
[0011]
On the other hand, a photorefractive material using a single crystal of an organic low molecular compound is also known, but such a material also has low moldability and has not been put to practical use (P. Gunter et. Al., Solid State Commun. 66, {1846} (1991)).
[0012]
In such a technical background, research on a photorefractive material using an amorphous polymer compound having high moldability and transparency is being actively conducted in recent years.
[0013]
As an initial study example of such an amorphous polymer, it is proposed that a colorless and transparent polymer compound such as an epoxy resin is used as a base material, and a functional compound necessary for obtaining a photorefractive effect is added thereto and mixed. Was done. Although such a material has excellent properties such as moldability, a large amount of a polymer not involved in the photorefractive effect is added to the material, so that photorefractive properties such as diffraction efficiency are not sufficient (W.ΔE). {Moerner et. Al.} Phys. Rev. Lett. 66, 1846 (1991)).
[0014]
Next, attempts have been made to obtain a desired material by using a high molecular compound having a photocarrier generating function or a nonlinear optical function as a base resin and imparting a function not present in the material by adding and mixing a low molecular compound.
[0015]
In particular, a low molecular compound having a non-linear optical function such as 2,5-dimethyl-4- (p-nitrophenylazo) anisole, and a high molecular compound having a photocarrier generating function such as polyvinyl carbazole; A low molecular weight compound having a sensitizer such as 4,4,7-trinitro-9-fluorenone was added, and ethylcarbazole was added as a plasticizer to lower the glass transition temperature of the polymer composition to around room temperature. Materials have been proposed. Such materials have moldability and have high photorefractive properties over inorganic materials (N. Peyhambarian et. Al. Nature 371, 497 (1994)).
[0016]
The high photorefractive property obtained from the polymer material is such that the addition of a plasticizer lowers the glass transition temperature of the material and facilitates molecular motion. On the other hand, it is considered that the molecular orientation can be changed quickly, and as a result, a large nonlinear optical response is easily generated. This is called an orientation enhancement effect.
[0017]
In order to obtain the photorefractive effect from the above, a material that has a photocarrier generation / transport function and a nonlinear optical function, is transparent, and is easy to obtain orientation enhancement, that is, a material having a low glass transition temperature. Is considered important. However, such a material requires a large amount of a plasticizer to lower the glass transition temperature, and when left for a long period of time, the stability of the material over time, such as the precipitation (crystallization) of the plasticizer, is low. Has become an obstacle. Therefore, there is a strong demand for a material having the above-mentioned functions and high stability over time.
[0018]
[Problems to be solved by the invention]
In order to solve the problems of the conventional photorefractive material based on a polymer compound, the present inventors have in the same molecule the main function necessary for the expression of photorefractive properties, and have a low functionality such as a plasticizer. Intensive research was conducted to obtain a material free from concerns about molecular compound precipitation.
[0019]
As a result, a compound having a photocarrier generation / transport function such as carbazole and a compound having a non-linear optical function such as dicyanovinylaniline analog are respectively added to a bifunctional diisocyanate compound via an alkylene group. The present inventors have found that the urethane compound has high photorefractive properties, and have completed the present invention.
[0020]
Summary of the Invention
The present invention provides a compound represented by the following formula (I).
AR₁-OCONH-G-NHCOO-R₂−P (I)
In the formula, G is an aromatic or alicyclic divalent organic group, and is preferably a residue derived from an asymmetric reactive diisocyanate compound. A is a nonlinear optical function group, and P is an optical carrier generation / transport function group. Also, R₁And R₂Is an alkylene group having 2 to 12 carbon atoms, which may be the same or different.
The present invention also provides an organic photorefractive material obtained by mixing a sensitizer with the compound.
[0021]
As shown in the formula (I), this compound can be used for an aromatic diisocyanate compound having two isocyanate groups (preferably having different reactivities) with a photocarrier generation / transport function group and a nonlinear optical function group. Are compounds bonded via a urethane skeleton. This compound has low crystallinity, and once heated and melted above its melting point, quenched, and then converted to a supercooled liquid, it becomes a glassy solid without crystallization at room temperature and forms a transparent thin film like a polymer compound. Is possible.
[0022]
DETAILED DISCLOSURE OF THE INVENTION
Next, the present invention will be described in more detail. The lower formula (I) of the present invention:
AR₁-OCONH-G-NHCOO-R₂−P (I)
Specific examples of the compound represented by are P (photocarrier and transport functional group).
Embedded image

It is preferably any one of
[0023]
A (nonlinear optical function group)
Embedded image

(In the formula, n means an integer of 0 to 10.)
It is preferably any one of
[0024]
Examples of G that is an aromatic ring or alicyclic divalent organic group include the following (8) to (13).
Embedded image

(In the formula, m means an integer of 1 to 4.)
[0025]
Among the compounds of the present invention, examples of particularly preferred compounds include the following formula (14):
Embedded image

And a urethane compound derived from an asymmetric reactive diisocyanate compound represented by
[0026]
(Method for producing the urethane compound of the present invention)
Next, a method for producing the compound of the formula (I) will be described. According to a typical production method of the compound of the formula (I), a diisocyanate compound (1) having two isocyanate groups (preferably having different reactivity: asymmetric reactivity) is used to prepare the isocyanate group. A photocarrier generation / transport functional molecule (2) such as a hydroxyl group-containing carbazole derivative having high reactivity with a nonlinear optical functional molecule (3) such as a hydroxyl group-containing dicyanovinylaniline derivative.
[0027]
(1) Diisocyanate compound
Representative examples of the diisocyanate compound that can be used for the production of the compound of the present invention include 4- (2-isocyanato) ethylphenyl isocyanate, 4- (3-isocyanato) ethylphenyl isocyanate, in addition to 4-isocyanatobenzyl isocyanate. Isocyanato) propylphenyl isocyanate, 4- (4-isocyanato) butylphenyl isocyanate, 3-isocyanatomethylphenylisocyanate, 3- (2-isocyanato) ethylphenylisocyanate, 3- (3-isocyanato) propylphenylisocyanate , 3- (4-isocyanato) butylphenyl isocyanate, 2-isocyanatomethylphenylisocyanate, 2- (2-isocyanato) ethylphenylisocyanate, 2- (3-isocyanato) propylphenylisocyanate, 2 (4-isocyanato) and butyl phenyl isocyanate, asymmetry reactive diisocyanates having aromatic and aliphatic isocyanate groups in the molecule.
[0028]
Also, it is adjacent to two isocyanate groups such as 4-isocyanatomethyl-1-methylcyclohexyl isocyanate, 3-isocyanatomethyl-1-methylcyclohexyl isocyanate, and 2-isocyanatomethyl-1-methylcyclohexyl isocyanate. A diisocyanate compound which produces asymmetry due to steric hindrance of a substituent may be used (HWI I Peerings et. Al., J. Polym. Sci .: Part A: Polym. Chem. 39, 3112). 2001)).
[0029]
The structural formula of the isocyanate compound particularly preferred in the present invention is shown below.
Embedded image

(Wherein, m represents an integer of 1 to 4)
[0030]
In the present invention, when a starting diisocyanate compound having a different reactivity of an isocyanate group is used, a target product can be obtained without performing a complicated operation such as isolation of an intermediate in a synthesis process. In addition, this compound is a low-molecular compound but has low crystallinity, can form a glassy transparent thin film, and has excellent moldability.
[0031]
The diisocyanate has an isocyanate group (aromatic isocyanate group) bonded to an aromatic hydrocarbon and an isocyanate group (aliphatic isocyanate group) bonded to an aliphatic hydrocarbon in one molecule. The respective isocyanate groups have different reactivities depending on the substituent effect. That is, the nucleophilic addition reactivity of a hydroxyl group to an aromatic isocyanate group (urethane-forming reaction) is 100 to 300 times that of an aliphatic isocyanate group with the electron withdrawing property of an aromatic hydrocarbon when reaction conditions are selected. Is shown. Due to such a difference in reactivity, a compound having one function is bonded to an aromatic isocyanate group first, and then a compound having another function is bonded to an aliphatic isocyanate group, and an intermediate is isolated. It is possible to easily introduce different functional groups into the molecule without performing such steps.
[0032]
▲ 2 ▼ Photocarrier generation / transport molecule
In a typical production method of the compound of the present invention, one isocyanate group of the diisocyanate compound (1) reacts with a hydroxyl group-containing photocarrier generation / transport functional molecule (2). Preferred examples of such a photocarrier generation / transport functional molecule include compounds having a photocarrier generation / transport group at one end of a long-chain alkyl group and a hydroxyl group capable of reacting with an isocyanate at the other end.
The above (2) can be obtained by reacting a photocarrier generation / transport functional group with a long-chain alkyl alcohol.
[0033]
(A) The photocarrier generation / transport functional groups include primary or secondary such as carbazole, 4-aminophenyl-diphenylamine, tris (4-aminophenyl) amine, 4-amino-benzaldehyde-N, N-diphenylhydrazone. And the following compounds (1a to 4a) having a secondary amino group.
[0034]
Embedded image

[0035]
(B) Examples of the long-chain alkyl alcohol that reacts with the photocarrier generation / transport functional group include 2-chloroethanol, 4-chlorobutanol, 5-bromopentanol, and 6-bromohexanol in addition to 11-hydroxyundecyl bromide. , 8-bromooctanol and the like, and those derived from these compounds.
[0036]
(C) Particularly preferred as a photocarrier generation / transport functional molecule is a carbazole group which is a photocarrier generation / transport functional group at one end of a long-chain alkyl group such as N- (11-hydroxy) undecylcarbazole. And a compound having a hydroxyl group at the other end. This compound is produced by a nucleophilic substitution reaction of 11-hydroxyundecyl bromide and carbazole with a bromomethyl group in 11-hydroxyundecyl bromide by an amino group in carbazole.
[0037]
As a production method by a nucleophilic substitution reaction, generally known alkyl groups of amino groups such as dissolving the photocarrier / generating functional group and the long-chain alkyl alcohol in a solvent and heating and stirring under basic conditions. The reaction conditions may be selected. Specifically, a method of dissolving the substrate in a highly polar solvent such as N, N-dimethylformamide and adding a basic compound such as potassium hydroxide or potassium carbonate, or dissolving the substrate in a low polar solvent such as toluene, The reaction conditions in a two-phase system to which an aqueous sodium hydroxide solution is added can be appropriately selected.
[0038]
▲ 3 ▼ Nonlinear optical function molecule
Representative examples of the nonlinear optical functional molecule that reacts with the other isocyanate group include compounds having a nonlinear optical functional group at one end of a long-chain alkyl group and a hydroxyl group that reacts with the isocyanate at the other end. .
The above (3) can be obtained by reacting a nonlinear optical functional group with a long-chain alkyl alcohol.
[0039]
(A) Examples of the nonlinear optical functional groups include N-methyl-4-dicyanovinylaniline, N-ethyl-4-dicyanovinylaniline, N-propyl-4-dicyanovinylaniline, and N-butyl-4-dicyanovinylaniline. N-alkyldicyanoanilines such as N-ethyl-2-dicyanovinylaniline, N-propyl-2-dicyanovinylaniline and N-butyl-2-dicyanovinylaniline; Amino group-containing azo dye compounds such as Perth Orange 3 can be used, and compounds of the following formulas (5a) to (7a) are particularly preferable.
[0040]
Embedded image

(Where n is the same as above)
[0041]
(B) As the long-chain alkyl alcohol that reacts with the nonlinear optical functional group, any of those used in the above-described photocarrier generation / transport functional molecules may be used.
[0042]
(C) A preferred non-linear optical functional molecule is a non-linear optical functional group such as N- (5-hydroxy) pentyl-N-ethyl-4-dicyanovinylaniline at one end of a long-chain alkyl group. Those having a vinylaniline group or the like and having a hydroxyl group bonded to the isocyanate at the other end are exemplified. In order to produce such a compound, N-ethyl-4-formylbenzene and 5-bromopentanol are used, and a nucleophilic substitution reaction of an amino group in N-ethyl-4-formylbenzene for a bromomethyl group in 5-bromopentanol is performed. I do.
[0043]
The production method by a nucleophilic substitution reaction may be the same conditions as described above. When 5-bromopentanol is used as it is, the synthesis operation may be complicated in the later-described dicyanomalonic acid condensation and the yield may be reduced. Therefore, the hydroxyl group is protected instead of 5-bromopentanol. It is also possible to use compounds, ie synthetic equivalents. Here, examples of the synthetic equivalent include 1-acetoxy-5-bromopentane obtained by reacting the hydroxyl group of 5-bromopentanol with acetic anhydride. This synthetic equivalent can be directly applied to the nucleophilic reaction, and thereafter, the target compound can be obtained in high yield by hydrolyzing the acetoxy group. Whether or not to use a synthetic equivalent can be appropriately selected depending on the yield and the reaction efficiency. Then, the aldehyde group of this intermediate and dicyanomalonic acid are condensed.
[0044]
(First stage: Reaction for aromatic isocyanate group)
Next, the operation of reacting the diisocyanate compound with two kinds of hydroxyl group-containing compounds (photocarrier generation / transport functional molecules and nonlinear optical functional molecules) will be described more specifically. In this case, a sequential reaction condition in which a more reactive aromatic isocyanate group is first reacted with one hydroxyl group-containing compound, and then the other hydroxyl group-containing compound is reacted with a less reactive aliphatic isocyanate group. Select
[0045]
Specifically, a hydroxyl group-containing compound is added in an equimolar amount to the isocyanate group of the diisocyanate compound at the beginning of the reaction. The addition is carried out slowly by a method such as dropping or powder addition, and the amount of the diisocyanate compound relative to the hydroxyl group-containing compound is always maintained in an excessive amount. In this manner, the reaction selectivity of the hydroxyl group-containing compound with respect to each isocyanate group in the diisocyanate compound is increased, and a sequential reaction is enabled.
[0046]
In order to increase the reaction selectivity at the beginning of the reaction, the reaction may be carried out slowly by lowering the reaction temperature as much as possible. However, if the reaction temperature is too low, the reaction efficiency is lowered, and side reactions such as isocyanate trimerization, which compete at the time of urethane bond formation, also easily proceed. Therefore, the reaction temperature is preferably from -10 to 30 ° C, and it is particularly preferable to add the hydroxyl group-containing compound at about 0 ° C.
[0047]
As the solvent used in the reaction, aliphatic hydrocarbons such as cyclohexane, pentane and hexane; aromatic hydrocarbons such as benzene, toluene and chlorobenzene; ethers such as THF (tetrahydrofuran), diethyl ether and ethylene glycol diethyl ether; Ketones such as acetone, methyl ethyl ketone and 4-methyl-2-pentanone; low polar solvents such as esters such as methyl propionate, ethyl acetate and butyl acetate are preferred. Thereafter, for the completion of the reaction, a high-polarity solvent may be added as it is, or alternatively, a low-polarity solvent may be removed by distilling off the low-polarity solvent, and the like. As the low polarity solvent, ethers such as THF are particularly preferable in consideration of reaction operability and monomer substrate solubility.
In order to improve the reaction selectivity, the monomer substrate concentration during the reaction is preferably low. However, in consideration of the reaction efficiency and the reaction operation, a solvent is used so that the monomer substrate becomes 0.1 to 0.3 mol / l. Is preferred.
[0048]
Examples of the catalyst include tertiary alkylamines such as N, N, N ′, N′-tetramethyl-1,3-butanediamine, triethylamine and tributylamine for efficient urethane bond formation; 1,4-diazabicyclo [ Condensed amines such as 2.2.2] octane, 1 ［, 8-diazabicyclo [5.4.0] undec-7-ene; alkyltins such as dibutyltin dilaurate (DBTL), tetrabutyltin and tributyltin acetate Are used. Among them, alkyltins and condensed amines are catalysts having higher activity for urethane bond formation reaction than alkylamines (F. Hostettler and EF Cox, Ind. Eng. Chem., 52). , 609-610, {(1960)].
[0049]
In using these catalysts, it is preferable to use a trialkylamine in order to lower the reaction selectivity at the beginning of the reaction, and then it is preferable to carry out the reaction efficiently using a highly active catalyst. The catalytic amount of the trialkylamine is preferably 1 to 30 mol% based on the monomer substrate in consideration of the reaction selectivity, the reaction efficiency, and the reaction operation.
[0050]
(2nd stage: Reaction of aliphatic isocyanate group)
After reacting the highly reactive aromatic isocyanate group with one of the photocarrier generation / transport functional molecule and the nonlinear optical functional molecule, which is a hydroxyl group-containing compound, the aliphatic isocyanate group and the other hydroxyl group-containing compound are reacted. To give the desired product.
[0051]
In this step, the reaction needs to be performed efficiently, and the solvent is preferably one having high substrate solubility. If an intermediate precipitates in the first stage of the reaction, a highly polar solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone is added. After distilling off the low-polarity solvent used in the initial stage of the reaction, these high-polarity solvents may be added. The amount of the solvent is preferably adjusted so that the substrate concentration becomes 10 to 30 mol%. The higher the concentration, the faster the reaction proceeds. However, if the concentration is too high, a by-product may be generated due to a biuret bond or an isocyanurate bond.
The amount of the catalyst is preferably 0.1 to 10 mol% based on the substrate. If the amount of the catalyst is larger than this, the above-mentioned side reaction may take precedence. To increase the reaction rate, an organotin-based catalyst such as DBTL is preferable.
[0052]
Under the above reaction conditions, for example, N- (11-hydroxy) undecylcarbazole as a photocarrier generation / transport functional molecule and N- (5 as a non-linear optical functional molecule with respect to 4-isocyanatomethylphenylisocyanate, for example. -Hydroxy) pentyl-N-ethyl-dicyanovinylaniline was reacted to obtain the desired product (isolation yield: 56%). This compound dissolves in a solvent and crystallizes when left at room temperature and precipitates as an opaque solid (melting point Tm: 90 ° C.). However, when heated and melted above its melting point and rapidly cooled, an amorphous solid having a glass transition point (Tg) of 24 ° C. It became. That is, this compound is heat-treated to be a supercooled liquid, thereby preventing crystallization and becoming a glassy solid, and can be used as a photorefractive material. In addition, since the glass transition temperature of this compound is lower than room temperature, it is possible to obtain a molecular orientation effect (orientation enhancement effect) even at around room temperature without blending a plasticizer or the like, and has a high fluidity and a molding process. The properties are also good.
[0053]
(Preparation of photorefractive material)
Next, a photorefractive material was prepared using the compound of the present invention, and its properties were examined. The compound of the present invention can be used as it is as a photorefractive material, but it is preferable to add a sensitizer in advance in order to improve the utilization efficiency of light irradiation energy.
[0054]
Such sensitizers include fullerene (C₆₀) And C₇₀And 2,4,7-trinitrofluorenone, 2,4,7-trinitro-9-fluorenylidenemalonitrile and the like are preferred. The use amount of the sensitizer may be appropriately adjusted, but is preferably 0.01 to 1 part by weight based on 100 parts by weight of the compound of the formula (I). If the amount of the sensitizer is less than this, the effect is not sufficient. On the other hand, if the amount is more than this, there is a possibility that a mixture is precipitated or dielectric breakdown is caused.
[0055]
In preparing a photorefractive material, it is necessary to uniformly mix the components and dissolve it in an organic solvent to make it uniform, or mix it, or mix it as a solid and heat melt it to make it uniform according to the purpose. A method may be appropriately adopted.
[0056]
(Method of evaluating photorefractive effect)
In order to evaluate the photorefractive effect of the organic material obtained in the present invention, irradiation with coherent light was performed while applying a voltage. That is, the material was sandwiched between two electrode glass plates coated with an indium titanium oxide (ITO) electrode together with a spacer, heated and depressurized to remove microbubbles and the like in the material, and used for evaluation.
[0057]
The evaluation was performed on the diffraction efficiency, the gain constant, and the response speed. In addition, in order to promote the formation of a spatial electric field, a lead wire was attached to the ITO electrode at the glass end of the evaluation sample, and measurement was performed by applying a DC voltage. The diffraction efficiency was measured by degenerate four-wave mixing using a helium-neon laser as a coherent light source and writing s-polarized light and reading p-polarized light. The diffraction efficiency was determined from the obtained ratio of the intensity of diffracted light to the intensity of transmitted light. In addition, the response speed was obtained by the following equation 1 based on the measurement result in which the diffraction efficiency increases with time in the above diffraction efficiency measurement.
[0058]
(Equation 1)

(Where t is the elapsed measurement time (seconds), I (t) is the intensity of the diffracted light at the elapsed time (t), and (∞) is the intensity of the saturated diffracted light.)
[0059]
The gain constant was measured by two-wave mixing, and was written by writing s-polarized light. Based on the obtained beam intensity, an actual gain constant was calculated by the following equation 2 (Naoto Tsutsumi, Polymer Processing, 48, 20 (2000)).
[0060]
(Equation 2)

(Where L is the interaction length, and γ is the intensity ratio of the two output light beams.)
[0061]
【Example】
Next, the present invention will be described more specifically based on examples.
[Example 1]
(A) Synthesis of nonlinear optical functional molecules
16 ml of N-ethylaniline, 20 ml (119.6 mmol) of 1-acetoxy-5-bromopentane and 20 ml of triethylamine were added to 125 ml of toluene, followed by stirring at 120 ° C. for 19 hours. After the precipitate contained in the reaction mixture was filtered off, the low-boiling point product was distilled off, and the residue was further purified by column chromatography to obtain 14.8 g of N-ethyl-N- (5-acetyloxy) pentylaniline. . Yield 50%
[0062]
Next, 5.8 ml of phosphorus oxychloride was added to anhydrous dimethylformamide under ice cooling, and the mixture was stirred for 30 minutes to reach room temperature, and then 13.9 g of the above-mentioned N-ethyl-N- (5-acetyloxy) pentylaniline (55. 5 mmol) and stirred at 90 ° C. for 20 hours. 600 ml of water was poured into the reaction solution, and extracted with ether and chloroform in this order. After the organic layer was dried over anhydrous magnesium sulfate, the solvent was distilled off, and the obtained reaction mixture was purified by column chromatography to obtain 11.8 g of N-ethyl-N- (5-acetyloxy) pentyl-4-formylaniline. Got. Yield 77%.
[0063]
Finally, 3.3 g (50 mmol) of dicyanomalonic acid, 10.8 g (45.6 mmol) of N-ethyl-N- (5-acetyloxy) pentyl-4-formylaniline, and 0.7 g of N, N-dimethylaminopyridine (4.3 mmol) was added to 60 ml of isopropal and stirred at 40 ° C. for 3 days. The reaction mixture obtained by distilling off the solvent was added to ether and washed with water. After drying with magnesium sulfate in an organic layer, the solvent was distilled off, and the residue was further purified by column chromatography to obtain N- (5-hydroxy) pentyl-N-ethyl-4-dicyanovinylaniline which is a nonlinear optical functional molecule. 5 g were obtained. Yield 67%.
[0064]
(B) Synthesis of photocarrier generation / transport functional molecules
20.6 g (82.0 mmol) of 11-hydroxyundecyl bromide, 9.2 g (55 mmol) of carbazole, 0.4 g (1.7 mmol) of triethylbenzylammonium chloride and 10 g of sodium hydroxide were added to 50 ml of acetone, and the mixture was added at room temperature for 12 hours. Stirred. The reaction solution was filtered to remove insolubles, and the solvent was distilled off to obtain a reaction mixture. Water was added to the reaction mixture, and an arbitrary amount of concentrated hydrochloric acid was added to make an acidic aqueous solution, followed by extraction with ethyl acetate. The extracted organic layer was washed with an aqueous sodium hydrogen carbonate solution, water and saturated saline in this order, and dried over magnesium sulfate. The solvent was distilled off, and the obtained reaction mixture was purified by column chromatography to obtain N- (11-hydroxy) undecylcarbazole as a photocarrier generation / transport functional molecule. Yield 17.0 g (90% yield).
[0065]
(C) Production of photorefractive materials
To 0.49 g (2.8 mmol) of 4-isocyanatobenzyl isocyanate which is an asymmetric reactive diisocyanate, N- (5-hydroxy) pentyl-N-ethyl-4-dicyanovinylaniline of (a) was added. A THF solution (50 ml) of 78 g (2.8 mmol) and 0.03 g (0.3 mmol) of triethylamine was added over 1 hour under ice cooling, and the mixture was further stirred at 30 ° C. for 19 hours. Next, 0.95 g (2.8 mmol) of N- (11-hydroxy) undecylcarbazole of the above (b) and 0.02 g (0.04 mmol) of dibutyltin dilaurate were added, and the mixture was stirred for 19 hours while heating under reflux. did. The reaction mixture obtained by distilling off the solvent was purified by column chromatography to obtain the desired product. Yield 1.30 g (59% yield).
[0066]
That the obtained compound is the target compound¹H-NMR (FIG. 1),¹³It was confirmed by C-NMR (FIG. 2) and elemental analysis. Further, the compound was confirmed to be an amorphous solid having a glass transition temperature of 24 ° C. by differential scanning calorimetry (DSC) (FIG. 3).
[0067]
¹H-NMR (DMSO-d₆) {Δ} in} ppm: 1.09-1.74 (m, -CH₂-N-CH₂−CH ₃ , -CH₂−( CH ₂ ) ₉ -CH₂-, -CH₂−( CH ₂ ) ₃ -CH₂−, 27H), 3.30−3.49 (m, −CH ₂ -N-CH ₂ -CH₃, 4H), 3.92 (t, J = 6.4 Hz, -CH₂-Carbazole), 4.05-4.09 (m, 4H, -CH₂−O−) 4.36 (t, J = 6.4 Hz, −CH ₂ -C₆H₄), 6.82-8.14 (m, ΔC₆H₄, = CH-, -CH₂−NH-CO₂−, 18H), 9.54 (br, −C₆H₄−NH-CO₂−, 1H)
[0068]
¹³C-NMR (DMSO-d₆) Δ in ppm: 12.1, 22.7, 25.3, 26.5, 26.6, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, 42 .1, $ 43.3, $ 44.7, $ 63.7, $ 63.9, $ 69.1, $ 109.1, $ 111.6, $ 115.6, $ 116.4, $ 118.0, $ 118.4, $ 118.6 , $ 120.2, $ 122.0, $ 125.6, $ 127.4, $ 133.8, $ 133.9, $ 137.9, $ 139.9, 152.5, $ 153.6, $ 156.5, $ 158.5
[0069]

[0070]
(Manufacture of organic photorefractive materials)
A photorefractive material was prepared from the compound thus obtained as follows. That is, to 0.30 g of the compound obtained in the above (C), 0.0015 g of fullerene as a sensitizer was added to 5 ml of tetrahydrofuran. After dissolving the substrate and finely dispersing the fullerene by ultrasonic waves, the solution was filtered to remove impurities in the solution. The solvent was distilled off, followed by drying under reduced pressure to obtain a desired photorefractive material.
[0071]
A sample for measurement evaluation was prepared to confirm the photorefractive effect of the obtained material. That is, the above-mentioned material and a spacer (a Teflon (registered trademark) sheet having a thickness of 100 μm) were placed on a glass plate with an ITO electrode, and further sandwiched by another glass plate with an ITO electrode so that the ITO electrodes were opposed to each other to obtain a measurement evaluation sample. .
[0072]
Diffraction efficiency was measured by a degenerate four-wave mixing method. Specifically, the sample was placed at a tilt angle of 60 ° and measured by applying a DC voltage to the ITO electrode in order to promote the formation of a spatial electric field. A helium neon laser was used as a light source. The light source was divided into two parts, and irradiated with s-polarized interference light at an incident angle of 19 °. This was irradiated with p-polarized light extracted from the same light source as readout light, and the intensity of diffracted light was measured. As a result, it was found that the diffraction efficiency reached 15% when the DC voltage was 70 V / μm. At this time, the response speed was found to be 8 seconds by tracking the change in the intensity of the diffracted light from the start of the writing light irradiation until the diffraction efficiency reached 15%.
[0073]
When the p-polarized light was irradiated as the writing light under the same conditions as above, energy transfer between the two light beams was recognized, and the gain constant was 8 cm.^-1It turned out to be. Thus, it was found that the material of the present invention can obtain a high photorefractive effect.
[0074]
【The invention's effect】
The photocarrier-generating compound of the present invention has a simple production method and exhibits a liquid state, and a photorefractive material can be obtained without using a plasticizer. This photorefractive material has excellent photorefractive properties as compared with conventional materials, and has high moldability. The material of the present invention can provide an excellent spatial light modulator in the fields of optical communication and optical information processing.
[Brief description of the drawings]
FIG. 1 shows the results of the compound obtained in Example 1.¹It is an H-NMR spectrum.
FIG. 2 shows the results of the compound obtained in Example 1.¹³It is a C-NMR spectrum.
FIG. 3 is a measurement result by differential scanning calorimetry (DSC) of the compound obtained in Example 1.

Claims (6)

A compound represented by the following formula (I).
AR ₁ -OCONH-G-NHCOO-R ₂ -P (I)
(Wherein G is an aromatic ring or alicyclic divalent organic group, A is a nonlinear optical functional group, P is a photocarrier generation / transport functional group, and R ₁ and R ₂ are each independently a carbon atom. It means an alkylene group of the number 2 to 12.) In the formula (I), P is

Where A is

(In the formula, n means an integer of 0 to 10.)
A compound of claim 1 which means any of the following. G is

(In the formula, m means an integer of 1 to 4.)
The compound according to claim 1, wherein the compound is The following equation (14):

The compound according to claim 2 or 3, which is represented by the formula: Reacting the photocarrier generation / transport function group and the nonlinear optical function group with the long-chain alkyl alcohol and the photocarrier generation / transport function molecule and the non-linear optical device molecule with the asymmetric reactive diisocyanate compound The resulting compound. An organic photorefractive material obtained by mixing a sensitizer with the compound according to claim 1.

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