JP3588813B2 - Dichroic dye, liquid crystal composition containing the dye, and liquid crystal device - Google Patents

Description

【０００９】
（式中、Ｒ¹ 、Ｒ² はアルキル基、アルコキシアルキル基、フルオロアルキル置換アルキル基、または、アルキル基、アルコキシ基、或いはハロゲン原子を置換基として有していてもよいアラルキル基を示し、また、Ｒ¹ とＲ² は互いに連結して含窒素脂肪族環を形成してもよい。Ｒｆは炭素数１〜１２のパーフルオロアルキル基もしくはω−Ｈ−パーフルオロアルキル基を示す。Ｚ¹ 〜Ｚ⁹ はそれぞれ水素原子、ハロゲン原子、メチル基またはメトキシ基を示し、Ｚ¹ とＺ² 、Ｚ⁴ とＺ⁵ またはＺ⁷ とＺ⁸ は互いに連結して脂肪族環、芳香族環または含窒素芳香族環の一部を形成してもよい。ｍは１または２、ｎは１〜８の数を示す。）で表されるパーフルオロアルキルアルキルスルホニル基を含有するジスアゾ系またはトリスアゾ系二色性色素に存する。
本発明のジス又はトリスアゾ系二色性色素は下記の反応式
【００１０】
【化３】

【００１１】
により合成されるパーフルオロアルキルアルキルスルホニル基を含むアニリン類を用いて、公知のジアゾ化カップリング反応を適用することにより合成することができる。
【００１２】
前示一般式〔Ｉ〕に於けるＲ^１ 、Ｒ^２ はそれぞれ独立にメチル、エチル、直鎖状または分枝状のプロピル、ブチル、ヘキシル、オクチルなどのＣ１〜Ｃ１８のアルキル基、エトキシメチル、ブトキシメチル、エトキシエチル、ブトキシエチルなどのアルコキシアルキル基、パーフルオロエチルメチル、パーフルオロブチルエチル、パーフルオロヘキシルエチルなどのフルオロアルキル置換アルキル基、ベンジル、フェネチル、４−ブチルベンジル、４−ブトキシエチルベンジル、４−ペントキシベンジル、４−クロルベンジルなどの置換基（例えばアルキル基、アルコキシ基、ハロゲン原子）を有していてもよいアラルキル基が挙げられ、またＲ^１ 、Ｒ^２ は互に連結してピロリジン環、ピペリジン環、モルホリン環などの含窒素脂肪族環を形成してもよい。
【００１３】
Ｒｆはトリフルオロメチル基、ペンタフルオロエチル基、ヘプタフルオロプロピル基、ノナフルオロブチル基、ウンデカフルオロペンチル基、ヘプタデカフルオロオクチル基などの炭素数１〜１２のパーフルオロアルキル基もしくは３Ｈ−パーフルオロプロピル基、４Ｈ−パーフルオロブチル基、６Ｈ−パーフルオロヘキシル基、８Ｈ−パーフルオロオクチル基など末端に水素原子を１個含有する炭素数１〜１２のω−Ｈ−パーフルオロアルキル基を示す。
【００１４】
Ｚ^１ 〜Ｚ^９ は、それぞれ、水素原子、ハロゲン原子、メチル基またはメトキシ基を示し、Ｚ^１ とＺ^２ 、Ｚ^４ とＺ^５ またはＺ^７ とＺ^８ が互いに連結した場合はテトラリン環の脂肪族環部分、ナフタリン環の芳香族環部分またはキノリン環の含窒素芳香環部分を形成してもよく、Ｒ^１ とＺ^８ またはＲ^２ とＺ^９ は互に連結してジュロリジン環、テトラヒドロキノリン環の含窒素脂肪族環部分を形成してもよい。
【００１５】
本発明の二色性色素の中でも、特にジスアゾ系色素は特に赤色系でも青味赤色〜赤紫の深色系の色相を有する為、ブラックの液晶組成物の成分として有用である。
【００１６】
本発明の液晶組成物は前示一般式〔Ｉ〕で示されるアゾ系二色性色素を、〔液晶デバイスハンドブック：日本学術振興会第１４２委員会編（１９８９）；ｐ１５４〜ｐ１９２，ｐ７１５〜ｐ７２２〕記載のネマチックあるいはスメクチック相を示すビフェニル系、フェニルシクロヘキサン系、フェニルピリミジン系、シクロヘキシルシクロヘキサン系などの各種の液晶化合物または液晶組成物に公知の方法で混合することにより容易に調製することができる。このような液晶化合物の例としては、特開平３−１４８９２号公報等に記載の化合物が挙げられる。この他、ＴＦＴ液晶素子に用いられるフッ素系液晶も好適に使用できる。
【００１７】
また本発明の液晶組成物はコレステリルノナノエートなどの液晶相を示しても示さなくても良い光学活性化合物を含有してもよく、あるいは紫外線吸収剤、酸化防止剤などの各種の添加剤を含有しても良い。
【００１８】
このようにして得られた液晶組成物を、少なくとも一方が透明な電極付基板間に挟持することにより、ゲストホスト効果を応用した素子〔松本正一、角田市良“液晶の最新技術”工業調査会，３４（１９８３）；Ｊ．Ｌ．Ｆｅｒｇａｓｏｎ，ＳＩＤ８５Ｄｉｇｅｓｔ，６８（１９８５）等〕などを構成することができる。該基板としては通常ガラス板或いはアクリル樹脂、ポリカーボネート樹脂、エポキシ樹脂等の各種合成樹脂板が挙げられ、その基板上に電極層が形成される。透明電極層としては、酸化インジウム、酸化インジウムスズ（ＩＴＯ）、酸化スズ等の金属酸化物から成るものが通常使用される。透明電極層の液晶に接する表面は必要に応じて配向処理を施す。該配向処理の方法としては、例えばポリイミドを塗布して平行配向にする方法、ＳｉＯを斜めの角度から蒸着して平行配向にする方法等が適宜用いられる。
【００１９】
通常、基体は互に配向処理層面が対向するようにしてスペーサー等を介して一体化し、１〜５０μ好ましくは１〜１５μの素子間隔の素子を構成し、この素子間隔の中に液晶を封入することにより液晶素子が作成される。
【００２０】
【発明の効果】
本発明の高い二色性と高い着色力をもつ赤色系の二色性色素およびこれを含むフッ素系液晶組成物などにより、コントラストおよび耐久性に優れた表示素子などの液晶素子を構成することができる。
【００２１】
【実施例】
次に、本発明を実施例により、具体的に説明するが本発明はこれら実施例により何ら限定されるものではない。
【００２２】
実施例１
ジメチルホルムアミド２０ｍｌにＰ−ニトロチオフェノール３０ｍｍｏｌを加えて、撹拌下にナトリウムハイドライド５０ｍｍｏｌを添加し、室温で３時間撹拌したのち、２−（パーフルオロブチル）エチルアイオダイド３５ｍｍｏｌを加えて、窒素雰囲気下に室温で一夜間撹拌して反応させた。次いで反応混合物を水１５０ｍｌ中に排出して黄色の析出物を濾取、ヘキサンから再結晶して下記構造の目的物を得た。
【００２３】
【化４】

【００２４】
以下に本化合物の物性値を示す。
ｂｐ１３６℃／１．０ｍｍＨｇ；
^１ＨＮＭＲ（ＣＤＣｌ_３ ）δ２．５０（ｔｔ，Ｊ＝１６．５ａｎｄ８．２Ｈｚ，２Ｈ），３．２９（ｔｔ，Ｊ＝８．２ａｎｄ２．４Ｈｚ，２Ｈ），７．３８（ｄ，Ｊ＝８．９Ｈｚ，２Ｈ），８．１８（ｄ，Ｊ＝８．９Ｈｚ，２Ｈ）；
ＥＩＭＳ（７０ｅＶ）ｍ／ｚ（ｒｅｌ ｉｎｔｅｎｓｉｔｙ）４０１（Ｍ^＋ ，１００），３７１（１８），１６８（２５）．
【００２５】
この化合物４ｍｍｏｌを酢酸１０ｍｌに加え、過マンガン酸カリ１０ｍｍｏｌを含む水７５ｍｌを４０℃で撹拌下に加え、１５分後に反応物をナトリウムハイドロサルファイトを含む過剰の水中に排出し、白色の析出物を濾取、ヘキサンから再結晶して下記の目的物を得た。
【００２６】
【化５】

【００２７】
以下に本化合物の物性値を示す。
ｍｐ１２１〜１２３℃；
^１ＨＮＭＲ（ＣＤＣｌ_３ ）δ２．０６（ｔｔ，Ｊ＝１７．１ａｎｄ８．２Ｈｚ，２Ｈ），２．８１（ｔｔ，Ｊ＝８．２ａｎｄ４．０Ｈｚ，２Ｈ），７．５９（ｄ，Ｊ＝８．５Ｈｚ，２Ｈ），７．９０（ｄ，Ｊ＝８．５Ｈｚ，２Ｈ）；
ＥＩＭＳ（７０ｅＶ）ｍ／ｚ（ｒｅｌ ｉｎｔｅｎｓｉｔｙ）４３３（Ｍ^＋ ，６），１８６（１００），１２２（７４），７７（３８）．
【００２８】
この化合物２ｍｍｏｌ、濃塩酸１２ｍｍｏｌをメタノール２５ｍｌとともに加熱還流させ、これに鉄粉１２ｍｍｏｌを徐々に加えて撹拌し、薄層クロマトにて原料物質の消失を確認したのち、苛性ソーダを含む過剰の水中に排出して析出物を瀘別し、次いでこれをメタノールを用いてソクレー抽出した。この抽出物を濃縮後、ジクロルメタンを用いてカラムクロマト精製を行ない下記の目的物を得た。
【００２９】
【化６】

【００３０】
以下に本化合物の物性値を示す。
^１ＨＮＭＲ（ＣＤＣｌ_３ ）δ２．５６（ｔｔ，Ｊ＝１７．７ａｎｄ８．４Ｈｚ，２Ｈ），３．２７（ｔｔ，Ｊ＝８．４ａｎｄ３．７Ｈｚ，２Ｈ），４．３０（ｂｒ ｓ，２Ｈ），６．７４（ｄ，Ｊ＝８．７Ｈｚ，２Ｈ），７．６８（ｄ，Ｊ＝８．７Ｈｚ，２Ｈ）；
ＥＩＭＳ（７０ｅＶ）ｍ／ｚ（ｒｅｌ ｉｎｔｅｎｓｉｔｙ）４０３（Ｍ^＋ ，６４），１５６（１００），１０８（６９），９２（７９），６５（５９）．
この化合物０．８ｇ（２ｍｍｏｌ）を含むアセトン−ジメチルホルムアミド混合液（混合比１：１）２０ｍｌへ濃塩酸０．５ｍｌを加え、０℃に冷却して亜硝酸ナトリウム０．１４ｇ（２ｍｍｏｌ）を含む水溶液５ｍｌを加えた。１５分後、この混合液に下記化合物
【００３１】
【化７】

【００３２】
０．４２ｇ（２ｍｍｏｌ）を含む水溶液１０ｍｌを０℃で加え、同温度で１時間撹拌し反応させた後、反応混合物を過剰の水に排出して析出物を濾取した。得られた生成物を水酸化ナトリウム４ｇを含む水溶液中で６時間還流させ、冷却後、目的物をジクロロメタンにより抽出し、ジクロロメタン：アセトンの４：１混合液を用いてカラムクロマトにより精製して下記構造のモノアゾ化合物を０．５ｇ（収率５０％）得た。
【００３３】
【化８】

【００３４】
以下に本化合物の物性値を示す。
ｍｐ１９７〜１９８℃；
^１ＨＮＭＲ（ＣＤＣｌ_３ ）δ２．６２（ｔｔ，Ｊ＝１８．０ａｎｄ８．２Ｈｚ，２Ｈ），３．３７（ｔｔ，Ｊ＝８．２ａｎｄ４．８Ｈｚ，２Ｈ），４．２２（ｂｒ ｓ，２Ｈ），６．７６（ｄ，Ｊ＝８．８Ｈｚ，２Ｈ），７．８６（ｄ，Ｊ＝８．８Ｈｚ，２Ｈ），８．０２（ｄ，Ｊ＝３．０Ｈｚ，４Ｈ）；
ＥＩＭＳ（７０ｅＶ）ｍ／ｚ（ｒｅｌ ｉｎｔｅｎｓｉｔｙ）５０７（Ｍ^＋ ，１８），１２０（４２），９２（１００）；
ＵＶ（ＥｔＯＨ）４２４ｎｍ（１９８００）．
【００３５】
上記構造式で示されるパーフルオロアルキルアルキルスルホニル基を含有するモノアゾ系化合物０．５ｇをアセトン、ジメチルホルムアミド（ＤＭＦ）、水混合物（アセトン：ＤＭＦ：水＝２：０．５：０．５）２５ｍｌ、濃塩酸０．２５ｍｌに溶解した後、０℃に冷却して、亜硝酸ナトリウム０．０７ｇを含む水溶液を加え、１５分後、このジアゾ液にＮ，Ｎ−ジエチルアニリン０．３ｇを含むアセトン５ｍｌを０℃で撹拌下に加え、同温度で１時間反応後、反応物を過剰の水に排出して析出物を濾取し、ジクロルメタンを用いてカラムクロマトにより精製し、下記構造式の色素を得た。
【００３６】
【化９】

【００３７】
この色素の物性値を以下に示す。
λｍａｘ（ＥｔＯＨ）：５０５ｎｍ
^１ＨＮＭＲ（ＣＤＣｌ_３ ）δ１．２６（ｔ，Ｊ＝７．０Ｈｚ，６Ｈ），２．６４（ｔｔ，Ｊ＝１８．０ａｎｄ８．４Ｈｚ，２Ｈ），３．３９（ｔｔ，Ｊ＝８．４ａｎｄ４．０Ｈｚ，２Ｈ），３．４９（ｑ，Ｊ＝７．０Ｈｚ，４Ｈ），６．７５（ｄ，Ｊ＝９．２Ｈｚ，２Ｈ），７．９１（ｄ，Ｊ＝９．２Ｈｚ，２Ｈ），７．９９（ｄ，Ｊ＝８．７Ｈｚ，２Ｈ），８．１０（ｄ，Ｊ＝８．７Ｈｚ，２Ｈ），８．１１（ｓ，４Ｈ）；
ＥＩＭＳ（７０ｅＶ）ｍ／ｚ（ｒｅｌ ｉｎｔｅｎｓｉｔｙ）６６７（Ｍ^＋ ，２３），１４８（１００）；
【００３８】
このアゾ系色素を商品名ＺＬＩ−１５６５（Ｅ，ＭＥＲＣＫ社製）として市販されているフェニルシクロヘキサン系液晶混合物に１ｗｔ％の濃度で溶解させ赤色のゲストホスト型液晶組成物を調製した。これをポリイミド系樹脂を塗布、硬化、ラビング処理した透明電極付きガラス基板を対向させ、液晶が平行配向となるように構成したギャップ９μのセルに封入した。
【００３９】
この赤色に着色したセルの配向方向に平行な直線偏光に対する吸光度（Ａ／／）および配向方向に垂直な直線偏光に対する吸光度（Ａ⊥）を測定し、その吸収ピーク（λｍａｘ：５１２ｎｍ）におけるオーダーパラメーター（Ｓ）を下記の式
【数１】
Ｓ＝（Ａ／／−Ａ⊥）／（Ａ／／＋２Ａ⊥）
から求めた結果、Ｓ＝０．７６であった。
【００４０】
上記のＺＬＩ−１５６５の代りに商品名ＺＬＩ−４７９２ （Ｅ．ＭＥＲＣＫ社製）として市販されているフッ素系液晶混合物を用いて、同様にしてオーダーパラメーターを求めた結果、Ｓ＝０．７６（λｍａｘ：５０６ｎｍ）であった。
【００４１】
実施例２
下記構造式で示されるパーフルオロアルキルアルキルスルホニル基を含有するモノアゾ系化合物
【００４２】
【化１０】

【００４３】
を用いて、実施例１と同様にして下記構造式の色素を得た。
【００４４】
【化１１】

【００４５】
この色素の物性値を以下に示す。
λｍａｘ（ＥｔＯＨ）：４９１ｎｍ
^１ＨＮＭＲ（ＣＤＣｌ_３ ）δ１．２６（ｔ，Ｊ＝７．０Ｈｚ，６Ｈ），２．６４（ｔｔ，Ｊ＝１６．５ａｎｄ８．８Ｈｚ，２Ｈ），３．３９（ｔｔ，Ｊ＝８．８ａｎｄ２．０Ｈｚ，２Ｈ），３．４９（ｑ，Ｊ＝７．０Ｈｚ，４Ｈ），６．７５（ｄ，Ｊ＝８．８Ｈｚ，２Ｈ），７．７８（ｄ，Ｊ＝８．８Ｈｚ，２Ｈ），７．９１（ｄ，Ｊ＝８．９Ｈｚ，２Ｈ），７．９９（ｄ，Ｊ＝８．９Ｈｚ，２Ｈ），８．０５−８．１３（ｍ，４Ｈ）；
ＥＩＭＳ（７０ｅＶ）ｍ／ｚ（ｒｅｌ ｉｎｔｅｎｓｉｔｙ）７６７（Ｍ^＋ ，１），１４８（１００）；
【００４６】
このアゾ系色素を実施例１と同様に商品名ＺＬＩ−１５６５（Ｅ．ＭＥＲＣＫ社製）として市販されているフェニルシクロヘキサン系液晶混合物に溶解させて液晶組成物を調製し、これをセルに封入した。その吸収ピーク（λｍａｘ：５０６ｎｍ）におけるオーダーパラメーター（Ｓ）は０．６５であった。
【００４７】
上記のＺＬＩ−１５６５の代りに商品名ＺＬＩ−４７９２ （Ｅ．ＭＥＲＣＫ社製）として市販されているフッ素系液晶混合物を用いて、同様にしてオーダーパラメーター（Ｓ）を求めた結果、Ｓ＝０．６５（λｍａｘ：５０４ｎｍ）であった。
【００４８】
実施例３
上記の実施例１，２に準じた方法により得られたアゾ系色素のフッ素系液晶混合物：商品名ＺＬ１−４７９２（Ｅ．ＭＥＲＣＫ社製）中におけるオーダーパラメーター（Ｓ）と色相を表−１に示す。尚、表１中、Ｎｏ．９とＮｏ．１０は参考例である。
【００４９】
【表１】

【００５０】
【表２】

[0001]
[Industrial applications]
The present invention relates to a novel red to blue azo dichroic dye, a liquid crystal composition containing the same, and a liquid crystal device.
[0002]
[Prior art]
At present, various display modes other than a twist nematic (TN) type display mode and a super twist (STN) mode have been proposed as liquid crystal displays. Among them, a guest-host (GH) type display system using a dye dissolved in a liquid crystal is widely used as a display panel of an automobile or the like because of a feature such as a wide viewing angle.
[0003]
As the characteristics of the dichroic dye used in the GH mode, the following items 1) dichroism 2) solubility 3) light resistance 4) excellent coloring power are required.
[0004]
On the other hand, as the red dichroic dye required for forming a black liquid crystal composition having a large market need, a dye having an alkyl group, a nitro group, or a cyano group at a terminal has been conventionally known. . As a substituent containing a fluorine atom, a trifluoromethyl group has been studied, but other groups are not yet sufficient.
[0005]
However, conventional dichroic dyes having a nitro group or a cyano group have great disadvantages in light resistance and solubility, and dyes having an alkyl group tend to have a pale hue such as yellowish red and bluish red. However, it is difficult to obtain a deep color hue.
Further, there is a problem that these conventional dyes have insufficient affinity such as solubility with respect to a fluorine-based liquid crystal compound used in recent TFT liquid crystal devices and the like.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a red dichroic dye having less of the above-mentioned difficulties, a liquid crystal composition containing the same, and a liquid crystal element.
[0007]
[Means for Solving the Problems]
The present inventors have found that a disazo-based or trisazo-based dye containing a perfluoroalkylalkylsulfonyl group has excellent solubility in a fluorine-based liquid crystal compound and exhibits deep red color, and has reached the present invention. That is, the gist of the present invention is represented by the following general formula [I]
[0008]
Embedded image

[0009]
(Wherein, R ^1, R ² is an alkyl group, an alkoxyalkyl group, fluoroalkyl-substituted alkyl group, or an alkyl group, an alkoxy group, or an aralkyl group which may have a halogen atom as a substituent, also , R ¹ and R ² are linked may form a nitrogen-containing aliphatic ring .Rf together .Z ¹ ~ showing a perfluoroalkyl group or omega-H- perfluoroalkyl group having 1 to 12 carbon atoms Z ⁹ represents a hydrogen atom, a halogen atom, a methyl group or a methoxy group, and Z ¹ and Z ² , Z ⁴ and Z ⁵ or Z ⁷ and Z ⁸ are mutually linked to form an aliphatic ring, an aromatic ring or a nitrogen-containing group. May form a part of an aromatic ring, m represents 1 or 2, and n represents a number of 1 to 8.) Disazo or trisazo bicolor containing a perfluoroalkylalkylsulfonyl group represented by the formula: Sex pigment Exist for.
The di- or trisazo-based dichroic dye of the present invention has the following reaction formula:
Embedded image

[0011]
Can be synthesized by applying a known diazotization coupling reaction using an aniline containing a perfluoroalkylalkylsulfonyl group synthesized by the above method.
[0012]
In the general formula [I], R ¹ and R ² each independently represent a C1 to C18 alkyl group such as methyl, ethyl, linear or branched propyl, butyl, hexyl, octyl, etc., ethoxymethyl, Alkoxyalkyl groups such as butoxymethyl, ethoxyethyl and butoxyethyl; fluoroalkyl-substituted alkyl groups such as perfluoroethylmethyl, perfluorobutylethyl and perfluorohexylethyl; benzyl, phenethyl, 4-butylbenzyl and 4-butoxyethylbenzyl And an aralkyl group which may have a substituent (eg, an alkyl group, an alkoxy group, a halogen atom) such as 4-pentoxybenzyl and 4-chlorobenzyl, and R ¹ and R ² are mutually linked. Nitrogen-containing aliphatic rings such as pyrrolidine ring, piperidine ring and morpholine ring It may be formed.
[0013]
Rf is a perfluoroalkyl group having 1 to 12 carbon atoms such as a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, an undecafluoropentyl group, a heptadecafluorooctyl group, or 3H-perfluoro. A ω-H-perfluoroalkyl group having 1 to 12 carbon atoms and having one terminal hydrogen atom, such as a propyl group, a 4H-perfluorobutyl group, a 6H-perfluorohexyl group, and an 8H-perfluorooctyl group.
[0014]
Z ^{1 to} Z ⁹ each represent a hydrogen atom, a halogen atom, a methyl group or a methoxy group, and when Z ¹ and Z ² , Z ⁴ and Z ^5, or Z ⁷ and Z ⁸ are linked to each other, a tetralin ring aliphatic An aromatic ring moiety, an aromatic ring moiety of a naphthalene ring, or a nitrogen-containing aromatic ring moiety of a quinoline ring, wherein R ¹ and Z ⁸ or R ² and Z ⁹ are linked to each other to form a julolidine ring or a tetrahydroquinoline ring; May form a nitrogen-containing aliphatic ring moiety.
[0015]
Among the dichroic dyes of the present invention, disazo dyes are particularly useful as a component of a black liquid crystal composition because they have a deep red to reddish purple hue even in a red color.
[0016]
The liquid crystal composition of the present invention comprises an azo dichroic dye represented by the above general formula [I] [Liquid crystal device handbook: edited by the 142nd Committee of the Japan Society for the Promotion of Science (1989); p154-p192, p715-p722. The compound can be easily prepared by mixing a liquid crystal compound or a liquid crystal composition such as a biphenyl-based, phenylcyclohexane-based, phenylpyrimidine-based, or cyclohexylcyclohexane-based compound having a nematic or smectic phase described above with a known method. Examples of such a liquid crystal compound include compounds described in JP-A-3-14892 and the like. In addition, a fluorine-based liquid crystal used for a TFT liquid crystal element can be preferably used.
[0017]
The liquid crystal composition of the present invention may contain an optically active compound which may or may not show a liquid crystal phase such as cholesteryl nonanoate, or may contain various additives such as an ultraviolet absorber and an antioxidant. You may.
[0018]
An element utilizing the guest-host effect by sandwiching the thus obtained liquid crystal composition between substrates with at least one transparent electrode [Shoichi Matsumoto, Ichiyo Tsunoda “Latest Technology of Liquid Crystal” Association, 34 (1983); L. Fergason, SID85Digest, 68 (1985), etc.]. Examples of the substrate include a glass plate or various synthetic resin plates such as an acrylic resin, a polycarbonate resin, and an epoxy resin. An electrode layer is formed on the substrate. As the transparent electrode layer, one composed of a metal oxide such as indium oxide, indium tin oxide (ITO), and tin oxide is usually used. The surface of the transparent electrode layer in contact with the liquid crystal is subjected to an alignment treatment as needed. As a method of the alignment treatment, for example, a method of applying polyimide to make parallel alignment, a method of depositing SiO from an oblique angle to make parallel alignment, and the like are appropriately used.
[0019]
Usually, the substrates are integrated via a spacer or the like so that the surfaces of the alignment treatment layers face each other to form an element having an element spacing of 1 to 50 μm, preferably 1 to 15 μm, and a liquid crystal is sealed in the element spacing. Thus, a liquid crystal element is created.
[0020]
【The invention's effect】
By using the red dichroic dye having high dichroism and high coloring power of the present invention and a fluorine-based liquid crystal composition containing the same, a liquid crystal element such as a display element having excellent contrast and durability can be formed. it can.
[0021]
【Example】
Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.
[0022]
Example 1
30 mmol of P-nitrothiophenol was added to 20 ml of dimethylformamide, 50 mmol of sodium hydride was added with stirring, and the mixture was stirred at room temperature for 3 hours. Then, 35 mmol of 2- (perfluorobutyl) ethyl iodide was added, and the mixture was added under a nitrogen atmosphere. The reaction was stirred overnight at room temperature. Then, the reaction mixture was discharged into 150 ml of water, and a yellow precipitate was collected by filtration and recrystallized from hexane to obtain a target product having the following structure.
[0023]
Embedded image

[0024]
The physical properties of the compound are shown below.
bp 136 ° C./1.0 mmHg;
¹ H NMR (CDCl ₃ ) δ 2.50 (tt, J = 16.5 and 8.2 Hz, 2H), 3.29 (tt, J = 8.2 and 2.4 Hz, 2H), 7.38 (d, J = 8. 9 Hz, 2H), 8.18 (d, J = 8.9 Hz, 2H);
EIMS (70 eV) m / z (rel intensity) 401 (M ⁺ , 100), 371 (18), 168 (25).
[0025]
4 mmol of this compound was added to 10 ml of acetic acid, 75 ml of water containing 10 mmol of potassium permanganate was added under stirring at 40 ° C., and after 15 minutes, the reaction product was discharged into an excess of water containing sodium hydrosulfite to give a white precipitate. Was collected by filtration and recrystallized from hexane to give the following desired product.
[0026]
Embedded image

[0027]
The physical properties of the compound are shown below.
mp 121-123 ° C;
¹ H NMR (CDCl ₃ ) δ 2.06 (tt, J = 17.1 and 8.2 Hz, 2H), 2.81 (tt, J = 8.2 and 4.0 Hz, 2H), 7.59 (d, J = 8. 5 Hz, 2H), 7.90 (d, J = 8.5 Hz, 2H);
EIMS (70 eV) m / z (rel intensity) 433 (M ⁺ , 6), 186 (100), 122 (74), 77 (38).
[0028]
2 mmol of this compound and 12 mmol of concentrated hydrochloric acid were heated under reflux together with 25 ml of methanol, and 12 mmol of iron powder was gradually added thereto, followed by stirring. After confirming the disappearance of the raw material by thin layer chromatography, the solution was discharged into excess water containing caustic soda. The precipitate was filtered off and then extracted with methanol using Soclay. After concentrating this extract, column chromatography purification was performed using dichloromethane to obtain the following target compound.
[0029]
Embedded image

[0030]
The physical properties of the compound are shown below.
¹ H NMR (CDCl ₃ ) δ 2.56 (tt, J = 17.7 and 8.4 Hz, 2H), 3.27 (tt, J = 8.4 and 3.7 Hz, 2H), 4.30 (br s, 2H), 6.74 (d, J = 8.7 Hz, 2H), 7.68 (d, J = 8.7 Hz, 2H);
EIMS (70 eV) m / z (rel intensity) 403 (M ⁺ , 64), 156 (100), 108 (69), 92 (79), 65 (59).
0.5 ml of concentrated hydrochloric acid is added to 20 ml of an acetone-dimethylformamide mixed solution (mixing ratio 1: 1) containing 0.8 g (2 mmol) of this compound, cooled to 0 ° C., and contains 0.14 g (2 mmol) of sodium nitrite. 5 ml of an aqueous solution was added. After 15 minutes, the following compound was added to the mixture.
Embedded image

[0032]
10 ml of an aqueous solution containing 0.42 g (2 mmol) was added at 0 ° C., and the mixture was stirred and reacted at the same temperature for 1 hour. The reaction mixture was discharged into excess water, and the precipitate was collected by filtration. The obtained product was refluxed for 6 hours in an aqueous solution containing 4 g of sodium hydroxide, and after cooling, the desired product was extracted with dichloromethane and purified by column chromatography using a 4: 1 mixture of dichloromethane: acetone to obtain the following. 0.5 g (yield 50%) of a monoazo compound having the structure was obtained.
[0033]
Embedded image

[0034]
The physical properties of the compound are shown below.
mp 197-198 ° C;
¹ H NMR (CDCl ₃ ) δ 2.62 (tt, J = 18.0 and 8.2 Hz, 2H), 3.37 (tt, J = 8.2 and 4.8 Hz, 2H), 4.22 (br s, 2H), 6.76 (d, J = 8.8 Hz, 2H), 7.86 (d, J = 8.8 Hz, 2H), 8.02 (d, J = 3.0 Hz, 4H);
EIMS (70 eV) m / z (rel intensity) 507 (M ⁺ , 18), 120 (42), 92 (100);
UV (EtOH) 424 nm (19800).
[0035]
0.5 g of a monoazo compound containing a perfluoroalkylalkylsulfonyl group represented by the above structural formula is mixed with 25 ml of acetone, dimethylformamide (DMF) and water (acetone: DMF: water = 2: 0.5: 0.5). After dissolving in 0.25 ml of concentrated hydrochloric acid, the solution was cooled to 0 ° C., and an aqueous solution containing 0.07 g of sodium nitrite was added. After 15 minutes, acetone containing 0.3 g of N, N-diethylaniline was added to the diazo solution. 5 ml was added under stirring at 0 ° C., and after reacting at the same temperature for 1 hour, the reaction product was discharged into excess water, the precipitate was collected by filtration, and purified by column chromatography using dichloromethane to obtain a dye having the following structural formula Got.
[0036]
Embedded image

[0037]
The physical properties of this dye are shown below.
λmax (EtOH): 505 nm
_{^{1 HNMR (CDCl 3) δ1.26 (}} t, J = 7.0Hz, 6H), 2.64 (tt, J = 18.0and8.4Hz, 2H), 3.39 (tt, J = 8.4and4. 0 Hz, 2H), 3.49 (q, J = 7.0 Hz, 4H), 6.75 (d, J = 9.2 Hz, 2H), 7.91 (d, J = 9.2 Hz, 2H), 7.99 (d, J = 8.7 Hz, 2H), 8.10 (d, J = 8.7 Hz, 2H), 8.11 (s, 4H);
EIMS (70 eV) m / z (rel intensity) 667 (M ⁺ , 23), 148 (100);
[0038]
The azo dye was dissolved at a concentration of 1 wt% in a phenylcyclohexane-based liquid crystal mixture commercially available as ZLI-1565 (trade name, manufactured by MERCK) to prepare a red guest-host type liquid crystal composition. A glass substrate with a transparent electrode, which was coated with a polyimide resin, cured and rubbed, faced, and was sealed in a cell having a gap of 9 μm so that the liquid crystal was aligned in parallel.
[0039]
The absorbance (A //) for linearly polarized light parallel to the orientation direction and the absorbance (A⊥) for linearly polarized light perpendicular to the orientation direction of the cell colored in red were measured, and the order parameter at the absorption peak (λmax: 512 nm) was measured. (S) is calculated by the following equation:
S = (A // − A⊥) / (A // + 2A⊥)
As a result, S = 0.76.
[0040]
As a result of similarly determining the order parameter using a fluorine-based liquid crystal mixture commercially available under the trade name ZLI-4792 (manufactured by E. MERCK) instead of ZLI-1565, S = 0.76 (λmax) : 506 nm).
[0041]
Example 2
A monoazo compound having a perfluoroalkylalkylsulfonyl group represented by the following structural formula:
Embedded image

[0043]
And a dye having the following structural formula was obtained in the same manner as in Example 1.
[0044]
Embedded image

[0045]
The physical properties of this dye are shown below.
λmax (EtOH): 491 nm
¹ H NMR (CDCl ₃ ) δ 1.26 (t, J = 7.0 Hz, 6H), 2.64 (tt, J = 16.5 and 8.8 Hz, 2H), 3.39 (tt, J = 8.8 and 2. 0 Hz, 2H), 3.49 (q, J = 7.0 Hz, 4H), 6.75 (d, J = 8.8 Hz, 2H), 7.78 (d, J = 8.8 Hz, 2H), 7.91 (d, J = 8.9 Hz, 2H), 7.99 (d, J = 8.9 Hz, 2H), 8.05-8.13 (m, 4H);
EIMS (70 eV) m / z (rel intensity) 767 (M ⁺ , 1), 148 (100);
[0046]
This azo dye was dissolved in a phenylcyclohexane-based liquid crystal mixture commercially available under the trade name ZLI-1565 (manufactured by E. MERCK) in the same manner as in Example 1 to prepare a liquid crystal composition, which was sealed in a cell. . The order parameter (S) at the absorption peak (λmax: 506 nm) was 0.65.
[0047]
The order parameter (S) was determined in the same manner by using a fluorine-based liquid crystal mixture commercially available under the trade name ZLI-4792 (manufactured by E. MERCK) instead of ZLI-1565, and as a result, S = 0. 65 (λmax: 504 nm).
[0048]
Example 3
Table 1 shows the order parameter (S) and hue in a fluorine-based liquid crystal mixture of an azo dye obtained by a method according to Examples 1 and 2 described above: trade name ZL1-4792 (manufactured by E. MERCK). Show. In Table 1, No. 9 and no. Reference numeral 10 is a reference example.
[0049]
[Table 1]

[0050]
[Table 2]

Claims (3)

The following general formula [I]

(Wherein, R ^1, R ² is an alkyl group, an alkoxyalkyl group, fluoroalkyl-substituted alkyl group, or an alkyl group, an alkoxy group, or an aralkyl group which may have a halogen atom as a substituent, also , R ¹ and R ² are linked may form a nitrogen-containing aliphatic ring .Rf together .Z ¹ ~ showing a perfluoroalkyl group or omega-H- perfluoroalkyl group having 1 to 12 carbon atoms Z ⁹ represents a hydrogen atom, a halogen atom, a methyl group or a methoxy group, and Z ¹ and Z ² , Z ⁴ and Z ⁵ or Z ⁷ and Z ⁸ are mutually linked to form an aliphatic ring, an aromatic ring or a nitrogen-containing group. May form a part of an aromatic ring, m represents 1 or 2, and n represents a number of 1 to 8.) Disazo or trisazo bicolor containing a perfluoroalkylalkylsulfonyl group represented by the formula: Sex pigment A liquid crystal composition comprising a liquid crystal compound and a diazo or trisazo dichroic dye containing the perfluoroalkylalkylsulfonyl group according to claim 1. A liquid crystal device comprising the liquid crystal composition according to claim 2 sandwiched between two substrates with electrodes, at least one of which is transparent.