JP4192231B2 - Biphenyl derivative oligomer and liquid crystal - Google Patents

Description

（式中、ｐ＝１、２，３； ｑ＝０，１，２； ｎ，ｍ，ｋ＝３〜１２）
【００１１】
【化７】

（式中、ｑ＝１、２、３； ｎ＝３〜１２）
【００１２】
【化８】

（式中、ｐ＝１、２； ｋ，ｍ＝３〜１２； Ｘ＝ハロゲン）
【００１３】
本発明の式Ｉ及び式ＩＩの新規化合物は液晶性を持つビフェニル誘導体からなる液晶オリゴマーである。本発明の液晶オリゴマーの好ましい態様は一般の低分子液晶とは異なった物性を示すことで、多量体型の液晶オリゴマーになるにつれ、液晶から液体への透明点のエンタルピー変化は大きくなり、多量体型の液晶オリゴマーでは液晶状態から温度を下げると液晶の構造のままで固体状態へと変わり、液晶構造を保持したままの固体状態を形成させることができること、などを含む特徴を提供する。
【００１４】
さらに本発明は、上記のビフェニル誘導体オリゴマーの製法に関するもので、４−シアノ−４’−ヒドロキシビフェニルに式ＩＶ
【化９】

（式中、ｎ＝３〜１２； Ｘはハロゲン原子）
を反応させ式Ｖの化合物を合成し、
【化１０】

（式中、ｎ＝３〜１２； Ｘはハロゲン原子）
次いで、式Ｖの化合物と４’−ヒドロキシ−４−ビフェニルカルボン酸を反応させ式ＩＩの化合物および式Ｉの化合物を合成し、
式ＩＩの化合物と式ＩＶの化合物とを反応させ式ＩＩＩの化合物および式Ｉの化合物を合成し、
必要があれば式ＩＩの化合物と式ＩＩＩの化合物または式ＩＩの化合物と式Ｖの化合物とを反応させて得られる請求項１に記載の式Ｉの化合物を製造する方法である。
【００１５】
【発明の実施の形態】
次ぎに式Ｉの化合物、式ＩＩの化合物、式ＩＩＩの化合物の合成と、多量体型の液晶オリゴマーの物性の特徴について述べる。
【００１６】
本発明で合成した４−シアノ−４’−ヒドロキシビフェニル、４’−ヒドロキシ−４−ビフェニルカルボン酸、炭素数３から１２のメチレン鎖からなる式Ｉの化合物である液晶構造が３個連結した液晶三量体、４個連結した液晶四量体、５個連結した液晶五量体、６個連結した液晶六量体、７個連結した液晶七量体は全て新規化合物であり、それらの新規化合物の構造は核磁気共鳴スペクトル（ＮＭＲ）、赤外吸収スペクトル（ＩＲ）、質量スペクトル（マススペクトル）、元素分析などの手段により同定された。
【００１７】
４−シアノ−４’−ヒドロキシビフェニルと式ＩＶのα，ω―ジブロモアルカンの等モルを有機溶媒たとえばＮ，Ｎ―ジメチルホルムアミド、ＤＭＳＯに溶かし、塩基たとえば炭酸カリウム等モルを加え１２時間から２４時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をクロロホルムに溶解し、シリカゲルカラムクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒）で分離する。式Ｖの化合物たとえばα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）アルカンと液晶二量体とを得る。α，ω―ジブロモアルカンの他にα，ω―ジクロロアルカンやα，ω―ジヨードアルカンでも同様の反応が起こる。
（反応式１）
【００１８】
【化１１】

（ただし、Ｘはハロゲン原子）
【００１９】
また４−シアノ−４’−ヒドロキシビフェニルと式ＩＶの化合物たとえばα，ω―ジブロモアルカンのモル比を変えることで、α−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）アルカンと液晶二量体の収量を変えることができる。
なお、α−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）アルカンと液晶二量体の収率はｎの数により変化する。
【００２０】
反応式１の生成物であるα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）アルカンと４’−ヒドロキシ−４−ビフェニルカルボン酸の等モルをＮ，Ｎ―ジメチルホルムアミドに溶かし、炭酸カリウムの等モルを加え１５時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をクロロホルムに溶解し、シリカゲルクロマトグラフ（展開溶媒：クロロホルムまたはクロロホルムとメタノールの混合溶媒）で分離し、式ＩＩの化合物（ｑ＝１）と式Ｉの液晶三量体（ｎ＝ｍ，ｐ＝１，ｑ＝０）を得る。式ＩＩの化合物（ｑ＝１）で末端がＣＯＯＨでなくＯＨであることはＮＭＲとＩＲから確認される。
（反応式２）
【００２１】
【化１２】

【００２２】
反応式２の生成物である式ＩＩの化合物（ｐ＝１）と式ＩＶのα，ω―ジブロモアルカンの等モルをＮ，Ｎ―ジメチルホルムアミドに溶かし、炭酸カリウムの等モルを加え１５時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をクロロホルムに溶解し、シリカゲルクロマトグラフ（展開溶媒：クロロホルムまたはクロロホルムとヘキサンの混合溶媒）で分離し、式ＩＩＩの化合物（ｐ＝１）と式Ｉの液晶四量体（ｎ＝ｋ，ｐ＝１，ｑ＝１）を得る。
（反応式３）
【００２３】
【化１３】

【００２４】
反応式３の生成物である式ＩＩＩの化合物（ｐ＝１、ｎ＝ｍ）と４’−ヒドロキシ−４−ビフェニルカルボン酸の等モルをＮ，Ｎ―ジメチルホルムアミドに溶かし、炭酸カリウムの等モルを加え１５時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をクロロホルムに溶解し、薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒またはクロロホルムとメタノールの混合溶媒）で分離し、式ＩＩの化合物（ｑ＝２）と式Ｉの液晶五量体（ｎ＝ｍ＝ｋ，ｐ＝２，ｑ＝１）を得る。
（反応式４）
【００２５】
【化１４】

【００２６】
反応式４の生成物である式ＩＩの化合物（ｐ＝２）と式ＩＶのα，ω―ジブロモアルカンの等モルをＮ，Ｎ―ジメチルホルムアミドに溶かし、炭酸カリウムの等モルを加え１５時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をクロロホルムに溶解し、薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒またはクロロホルム）で分離し、式ＩＩＩの化合物（ｎ＝ｍ，ｐ＝３）と式Ｉの液晶六量体（ｎ＝ｍ＝ｋ，ｐ＝２，ｑ＝２）を得る。
（反応式５）
【００２７】
【化１５】

【００２８】
反応式５の生成物である式ＩＩＩの化合物（ｎ＝ｍ，ｐ＝３）と４’−ヒドロキシ−４−ビフェニルカルボン酸の等モルをＮ，Ｎ―ジメチルホルムアミドに溶かし、炭酸カリウムの等モルを加え１５時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をクロロホルムに溶解し、薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒またはクロロホルム）で分離し、式ＩＩの化合物（ｑ＝３）と式Ｉの液晶七量体（ｎ＝ｍ＝ｋ，ｐ＝３，ｑ＝２）を得る。
（反応式６）
【００２９】
【化１６】

【００３０】
上記の反応式３から反応式６において、メチレン鎖の数の異なる化合物間で反応を行うことができる。このことはメチレン鎖の数の異なった組み合わせにより、多数の物性の異なる多様な式Ｉの液晶オリゴマーを作ることを可能とする。なおメチレン鎖の数の異なる式Ｉの液晶三量体（ｐ＝１，ｑ＝０）の合成は反応式７として行う。
【００３１】
反応式２の生成物であり、メチレン鎖の数がｎの式ＩＩの化合物（ｐ＝１）とメチレン鎖の数がｍのα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）アルカンの等モルをＮ，Ｎ―ジメチルホルムアミドに溶かし、炭酸カリウム等モルを加え１５時間室温で攪拌する。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルクロマトグラフ（展開溶媒：ヘキサンとクロロホルムの混合溶媒またはクロロホルム）で分離し、反応式７の生成物としてメチレン鎖の数がｎとｍからなる式Ｉの液晶三量体（ｐ＝１，ｑ＝０）を得る。
【００３２】
（反応式７）
【化１７】

【００３３】
本発明の液晶オリゴマーは純粋な分子であるという点で高分子液晶とは異なる。またメチレン鎖の数により液晶オリゴマーの物性は異なる。たとえば、一般に純粋な低分子液晶は結晶から液晶に変わる融点のエンタルピー変化は大きく、液晶から液体への透明点のエンタルピー変化は小さい。ホットプレート上での偏光顕微鏡観察および／または示唆走査熱量計（ＤＳＣ）を用いて、本発明で合成した液晶オリゴマーの熱的挙動を検討する。その結果、式Ｉのメチレン鎖の数やｐ、ｑの数が大きい多量体型の液晶オリゴマーの場合、液晶から液体への透明点のエンタルピー変化は融点のエンタルピー変化より大きくなる。このような物性は、一般の低分子液晶では起こらないことから、純粋な多量体型液晶オリゴマーの特徴を見出したことになる。
【００３４】
さらに、式Ｉのメチレン鎖の数やｐ、ｑの数が大きい多量体型の液晶オリゴマーでは液晶状態から温度を下げると液晶の組織構造のままで固体状態へと変わる。この物性は炭素数が１０のメチレン鎖の液晶オリゴマー（ｎ＝ｍ＝ｋ＝１０）において、液晶四量体から液晶七量体までのものに見出される。このことはその固体状態が液晶状態の組織構造を保ったまま結晶化していることを示している。この物性は流動性のある液晶の構造を操作することにより、その固体状態での組織構造を制御できることを示している点で重要であり、新しい機能材料設計に有用である。
【００３５】
【実施例】
実施例としてｎ＝ｍ＝ｋ＝１０の場合の液晶三量体から液晶七量体の合成とその物性、およびｎ＝３とｍ＝１２またはｎ＝１２とｍ＝３からなる液晶三量体とｎ＝ｋ＝３とｍ＝１２またはｎ＝ｋ＝１２とｍ＝３からなる液晶四量体の合成を示す。以下に、本発明の実施例を示すが、本発明はこの実施例によって制限されるものではない。
【００３６】
実施例１： （反応式１、ｎ＝１０）
４−シアノ−４’−ヒドロキシビフェニル（アメリカ合衆国Ａｌｄｒｉｃｈ社製）１０ｍｍｏｌと１，１０−ジブロモデカン（特級試薬 和光純薬工業株式会社）１０ｍｍｏｌを、Ｎ，Ｎ―ジメチルホルムアミド（特級試薬 ナカライ工業株式会社）２００ｍｌに溶かし、炭酸カリウム（特級試薬 ナカライ工業株式会社）１０ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒）で分離し、反応式１の生成物としてα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）デカンを収率６９％で、液晶二量体を収率９％で得た。
【００３７】
実施例２： （反応式２、ｎ＝ｍ＝１０）
反応式１の生成物α−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）デカン４ｍｍｏｌと４’−ヒドロキシ−４−ビフェニルカルボン酸（アメリカ合衆国Ａｌｄｒｉｃｈ社製）４ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド１００ｍｌに溶かし、炭酸カリウム４ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣を薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルム）で分離した。反応式２の生成物として式ＩＩの化合物（ｎ＝１０，ｑ＝１）を収率４７％で、式Ｉの液晶三量体（ｎ＝ｍ＝１０，ｐ＝１，ｑ＝０）を収率１４％で得た。式ＩＩの化合物（ｎ＝１０、ｑ＝１）の末端がＣＯＯＨでなくＯＨであることはＮＭＲとＩＲから確認された。式ＩＩの化合物（ｎ＝１０、ｑ＝１）のＮＭＲスペクトルを図１に示す。図１よりＣＯＯＨのピークは観測されず、ＯＨのピーク（δ５．２３）が観測されることから式ＩＩの化合物であると確認された。
【００３８】
実施例３ （反応式３、ｎ＝ｍ＝ｋ＝１０）
反応式２で得た式ＩＩの化合物（ｎ＝１０，ｐ＝１）２ｍｍｏｌと１，１０−ジブロモデカン２ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム２ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣を薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルムとヘキサンの７：３の混合溶媒）で分離し、反応式３の生成物として式ＩＩＩの化合物（ｎ＝ｍ＝１０，ｐ＝１）を収率５６％で、式Ｉの液晶四量体（ｎ＝ｍ＝ｋ＝１０，ｐ＝１，ｑ＝１）を収率１５％で得た。
【００３９】
実施例４ （反応式４、ｎ＝ｍ＝ｋ＝１０）
反応式３で得た式ＩＩＩの化合物（ｎ＝ｍ＝１０，ｐ＝１）１ｍｍｏｌと４’−ヒドロキシ−４−ビフェニルカルボン酸１ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム１ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣を薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルムとヘキサンの９：１の混合溶媒）で分離し、反応式４の生成物として式ＩＩの化合物（ｎ＝１０，ｑ＝２）を収率５３％で、式Ｉの液晶五量体（ｎ＝ｍ＝ｋ＝１０，ｐ＝２，ｑ＝１）を収率７％で得た。
【００４０】
実施例５ （反応式５、ｎ＝ｍ＝ｋ＝１０）
反応式４で得た式ＩＩの化合物（ｎ＝１０，ｐ＝２）０．５ｍｍｏｌと１，１０−ジブロモデカン０．５ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム０．５ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣を薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルム）で分離し、反応式５の生成物として式ＩＩＩの化合物（ｎ＝ｍ＝１０，ｐ＝３）を収率３２％と式Ｉの液晶六量体（ｎ＝ｍ＝ｋ＝１０，ｐ＝２，ｑ＝２）を収率９％で得た。この液晶六量体の核磁気共鳴スペクトル（ＮＭＲ）を図２に、質量スペクトル（マススペクトル）を図３に示す。質量スペクトルよりＭＮａ^＋が１９６１即ちこの分子の分子量が１９６１−２３（Ｎａの原子量）＝１９３８であることが分かる。ビフェニル誘導体の六量体であることが確かめられた。
【００４１】
実施例７ （反応式６、ｎ＝ｍ＝ｋ＝１０）
反応式５の生成物である式ＩＩＩの化合物（ｎ＝ｍ＝１０，ｐ＝３）（０．２５ｍｍｏｌ）と４’−ヒドロキシ−４−ビフェニルカルボン酸（０．２５ｍｍｏｌ）をＮ，Ｎ―ジメチルホルムアミド（２０ｍｌ）に溶かし、炭酸カリウム（０．５ｍｍｏｌ）を加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣を薄層シリカゲルクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒）で分離し、式ＩＩの化合物（ｎ＝１０，ｑ＝３）を収率９％で、式Ｉの液晶七量体（ｎ＝ｍ＝ｋ＝１０，ｐ＝３，ｑ＝２）を収率４％で得た。
【００４２】
実施例８：式Ｉ（ｎ＝ｍ＝ｋ＝１０）の液晶多量体の熱量変化
式Ｉ（ｎ＝ｍ＝ｋ＝１０）の液晶多量体の熱量変化を示差走査熱量計（ＤＳＣ）により測定した。式Ｉの液晶三量体（ｐ＝１、ｑ＝０）は先行技術１や先行技術２の液晶と類似した物性を示したが、式Ｉの液晶四量体（ｐ＝１、ｑ＝１）からは液晶多量体になるに従って、液晶から液体へのエンタルピー変化は大きくなり、式Ｉの液晶六量体（ｐ＝２、ｑ＝２）では融点のエンタルピー変化より大きくなった。
【００４３】
実施例９：式Ｉ（ｎ＝ｍ＝ｋ＝１０）の液晶多量体の偏光顕微鏡観察
式Ｉ（ｎ＝ｍ＝ｋ＝１０）の液晶多量体の熱的変化における相組織はホットプレート上での偏光顕微鏡観察により明らかにした。式Ｉの液晶三量体（ｐ＝１、ｑ＝０）では等方性液体の温度を下げるとネマチック相が現れ、さらに温度を下げると結晶化が起こったのに対し、式Ｉの液晶四量体（ｐ＝１、ｑ＝１）から式Ｉの液晶七量体（ｐ＝３、ｑ＝２）では等方性液体の温度を下げるとスメクチックＡ相が現れ、さらに温度を下げると液晶の相構造のままで固体状態へと変わった。式Ｉ（ｎ＝ｍ＝ｋ＝１０）の液晶多量体の相転移温度とエンタルピー変化を表１に示した。なお温度の上昇および降下は５℃／ｍｉｎで測定した。
【００４４】
【表１】

なお相転移温度とエンタルピー変化は一度その分子を加熱し、等方性液体とした後に温度を下げて固体状態と、そのまま１２時間以上室温に置いたサンプルを用いて行われた。ここでＫは固体、Ｎはネマチック液晶、Ｓ_ＡはスメクチックＡ液晶、Ｓ_ＣはスメクチックＣ液晶、Ｉは等方性液体を示す。
【００４５】
表１の結果の中で、式Ｉの液晶六量体（ｐ＝２、ｑ＝２）の熱量変化を説明する。その化合物は１３９℃でスメクチック相に変わり、そのときのエンタルピー変化は２６ｋＪ／ｍｏｌであった。さらに加熱すると１８３℃で等方性液体に変わり、そのときのエンタルピー変化は３３ｋＪ／ｍｏｌであった。等方性液体の温度を下げると１７９℃でスメクチック相に変わり、そのときのエンタルピー変化は３０ｋＪ／ｍｏｌであった。さらに温度を下げると１３３℃で固体に変わり、そのときのエンタルピー変化は２２ｋＪ／ｍｏｌであった（図４参照）。
このように液晶から液体へのエンタルピー変化は大きく、液晶六量体では融点のエンタルピー変化より大きくなった。この液晶六量体では液晶状態から温度を下げると１２９℃で固体に変わるが、そのとき液晶の相組織のままで固体状態へと変わった（図５参照）。同様に液晶七量体でもその固体状態は液晶状態の組織を保ったまま結晶になっていることが分かる（図５参照）。この液晶オリゴマーの液晶状態の組織を保ったままの結晶構造は１０日以上安定であった。
【００４６】
ｎ＝３とｍ＝１２またはｎ＝１２とｍ＝３からなる液晶三量体とｎ＝ｋ＝３とｍ＝１２またはｎ＝ｋ＝１２とｍ＝３からなる液晶四量体の合成とその液晶範囲について述べる。なお液晶範囲は示差走査熱量計（ＤＳＣ）で測定し、温度の上昇および降下は５℃／ｍｉｎで行った。
【００４７】
実施例１０： （反応式１、ｎ＝３）
４−シアノ−４’−ヒドロキシビフェニル（アメリカ合衆国Ａｌｄｒｉｃｈ社製）１０ｍｍｏｌと１，３−ジブロモプロパン（特級試薬 和光純薬工業株式会社）１０ｍｍｏｌを、Ｎ，Ｎ―ジメチルホルムアミド（特級試薬 ナカライ工業株式会社）２００ｍｌに溶かし、炭酸カリウム（特級試薬 ナカライ工業株式会社）１０ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒）で分離し、反応式１の生成物としてα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）プロパンを収率４８％で、液晶二量体を収率７％得た。
【００４８】
実施例１１： （反応式２、ｎ＝ｍ＝３）
実施例１０の生成物α−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）プロパン４ｍｍｏｌと４’−ヒドロキシ−４−ビフェニルカルボン酸（アメリカ合衆国Ａｌｄｒｉｃｈ社製）４ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド１００ｍｌに溶かし、炭酸カリウム４ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：ヘキサンとクロロホルム）で分離し、反応式２の生成物として式ＩＩの化合物（ｎ＝３，ｑ＝１）を収率２１％で式Ｉの液晶三量体（ｎ＝ｍ＝３，ｐ＝１，ｑ＝０）を収率９％で得た。式Ｉの液晶三量体（ｎ＝ｍ＝３，ｐ＝１，ｑ＝０）の液晶範囲は昇温過程で１８６℃−２４２℃、降温過程で２３９℃―１２０℃であった。
【００４９】
実施例１２： （反応式１、ｎ＝１２）
４−シアノ−４’−ヒドロキシビフェニル（アメリカ合衆国Ａｌｄｒｉｃｈ社製）１０ｍｍｏｌと１，１２−ジブロモドデカン（アメリカ合衆国Ａｌｄｒｉｃｈ社製）１０ｍｍｏｌを、Ｎ，Ｎ―ジメチルホルムアミド（特級試薬 ナカライ工業株式会社）２００ｍｌに溶かし、炭酸カリウム（特級試薬 ナカライ工業株式会社）１０ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：クロロホルムとヘキサンの混合溶媒）で分離し、反応式１の生成物としてα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）ドデカンを収率５５％で、液晶二量体を収率１２％得た。
【００５０】
実施例１３： （反応式２、ｎ＝ｍ＝１２）
実施例１２の生成物α−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）ドデカン４ｍｍｏｌと４’−ヒドロキシ−４−ビフェニルカルボン酸（アメリカ合衆国Ａｌｄｒｉｃｈ社製）４ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド１００ｍｌに溶かし、炭酸カリウム４ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：ヘキサンとクロロホルム）で分離し、反応式２の生成物として式ＩＩの化合物（ｎ＝１２，ｑ＝１）を収率３８％で式Ｉの液晶三量体（ｎ＝ｍ＝１２，ｐ＝１，ｑ＝０）を収率８％で得た。式Ｉの液晶三量体（ｎ＝ｍ＝１２，ｐ＝１，ｑ＝０）の液晶範囲は昇温過程で１５１℃−１６１℃で、降温過程で１５７℃―１１３℃であった。
【００５１】
実施例１４： （反応式７、ｎ＝３，ｍ＝１２）
実施例１１の生成物である式ＩＩの化合物（ｎ＝３，ｐ＝１）１ｍｍｏｌと実施例１２の生成物であるα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）ドデカン１ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム１ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：ヘキサンとクロロホルム）で分離し、反応式７の生成物として式Ｉの液晶三量体（ｎ＝３，ｍ＝１２、ｐ＝１，ｑ＝０）を収率３２％で得た。式Ｉの液晶三量体（ｎ＝３，ｍ＝１２、ｐ＝１，ｑ＝０）の液晶温度の範囲は昇温過程で１６１℃−２２２℃で、降温過程で２１９℃―９６℃であった。
【００５２】
実施例１５： （反応式７、ｎ＝１２，ｍ＝３）
実施例１３の生成物である式ＩＩの化合物（ｎ＝１２，ｐ＝１）１ｍｍｏｌと実施例１２の生成物であるα−ブロモ−ω―（４−シアノビフェニル−４’−イルオキシ）プロパンｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム１ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：ヘキサンとクロロホルム）で分離し、反応式７の生成物として式Ｉの液晶三量体（ｎ＝１２，ｍ＝３、ｐ＝１，ｑ＝０）を収率２５％で得た。式Ｉの液晶三量体（ｎ＝１２，ｍ＝３、ｐ＝１，ｑ＝０）の液晶温度の範囲は昇温過程で１３８℃−１５６℃、降温過程で１５１℃―８０℃であった。
【００５３】
実施例１６： （反応式３、ｎ＝ｋ＝３，ｍ＝１２）
実施例１１の生成物である式ＩＩの化合物（ｎ＝３，ｐ＝１）１ｍｍｏｌと１，１２−ジブロモドデカン１ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム１ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：ヘキサンとクロロホルム）で分離し、反応式８の生成物として式Ｉの液晶四量体（ｎ＝ｋ＝３，ｍ＝１２、ｐ＝１，ｑ＝１）を収率６％で、式ＩＩＩの化合物（ｎ＝３、ｍ＝１２，ｐ＝１）を収率３２％で得た。式Ｉの液晶四量体（ｎ＝ｋ＝３，ｍ＝１２、ｐ＝１，ｑ＝１）の液晶温度の範囲は昇温過程で１２４℃−２２１℃で、降温過程で２１９℃―６６℃であった。また式ＩＩＩの化合物（ｎ＝３、ｍ＝１２，ｐ＝１）の液晶温度の範囲は昇温過程で１２６℃−１７０℃で、降温過程で１６７℃―９７℃であった。
【００５４】
実施例１７： （反応式３、ｎ＝ｋ＝１２，ｍ＝３）
実施例１３の生成物である式ＩＩの化合物（ｎ＝１２，ｐ＝１）１ｍｍｏｌと１，３−ジブロモプロパン１ｍｍｏｌをＮ，Ｎ―ジメチルホルムアミド５０ｍｌに溶かし、炭酸カリウム１ｍｍｏｌを加え１５時間室温で攪拌した。反応液をろ過し、ろ液の溶媒を蒸留し、残渣をシリカゲルカラムクロマトグラフ（展開溶媒：ヘキサンとクロロホルム）で分離し、反応式８の生成物として式Ｉの液晶四量体（ｎ＝ｋ＝１２，ｍ＝３、ｐ＝１，ｑ＝１）を収率４％で、式ＩＩＩの化合物（ｎ＝１２、ｍ＝３，ｐ＝１）を収率３０％で得た。式Ｉの液晶四量体（ｎ＝ｋ＝１２，ｍ＝３、ｐ＝１，ｑ＝１）の液晶温度の範囲は昇温過程で１０１℃−１４７℃で、降温過程で１３８℃―９２℃であった。また式ＩＩＩの化合物（ｎ＝１２、ｍ＝３，ｐ＝１）の液晶温度の範囲は昇温過程で８９℃−１１９℃で、降温過程で１１６℃―５７℃であった。
【００５５】
比較例１： ｎ＝１０の液晶二量体の相転移
先行技術２の炭素数が１０（ｎ＝１０）のメチレン鎖の液晶二量体の熱量変化を示差走査熱量計（ＤＳＣ）により測定し、炭素数１０のメチレン鎖の液晶多量体と比較した。この液晶二量体は実施例１で得られた。この液晶二量体は１６４℃で固体から液晶に変わり、そのときのエンタルピー変化は３８ｋＪ／ｍｏｌであった。さらに温度を上げると１８２℃で等方性液体になり、そのときのエンタルピー変化は６ｋＪ／ｍｏｌであった。等方性液体から温度を下げると１８０℃で液晶に変わり、そのときのエンタルピー変化は６ｋＪ／ｍｏｌであった。さらに温度を下げると１２４℃で固体になり、そのときのエンタルピー変化は３７ｋＪ／ｍｏｌであった。このとき液晶構造とは異なった結晶構造が観測された。炭素数が１０のメチレン鎖の液晶二量体のＤＳＣチャート図を図面６に示す。炭素数１０のメチレン鎖の液晶六量体のＤＳＣチャート図（図面４）と比較すると、液晶二量体の固体から液晶へのエンタルピー変化は大きく、液晶から等方性液体へのエンタルピー変化は小さい。一方液晶六量体などの多量体型の液晶オリゴマーでは液晶二量体の固体から液晶へのエンタルピー変化は小さく、液晶から等方性液体へのエンタルピー変化は大きく、このことが多量体型の液晶オリゴマーの特徴であることが分かる。また液晶構造が変わらずに固体状態へと変化することも多量体型の液晶オリゴマーの特徴であることが分かる。
【００５６】
【発明の効果】
以上の説明から理解されるように本発明の新規な化合物は、末端のコア部分として４−シアノ−４’−ヒドロキシビフェニルを用い、内部のコア部分として４−シアノ−４’−ヒドロキシビフェニルと類似した非対象な分子である４’−ヒドロキシ−４−ビフェニルカルボン酸を用い、それらのコア部分を炭素数３から１２のメチレン鎖で連結した、純粋なオリゴマー分子である。
そのオリゴマー分子は液晶性を示し、しかも一般の低分子液晶とは異なる特徴を有している。また本発明の液晶オリゴマーは純粋な分子である点で高分子液晶と異なっている。
本発明の液晶オリゴマーの特徴的な物性は、一般の低分子液晶とは異なり透明点の大きなエンタルピー変化と液晶から固体状態に変わる際に液晶構造をそのまま保っているという点にある。このことは流動性のある液晶構造を操作することにより、その固体状態の構造を制御できる点で極めて有用である。
【００５７】
【図面の簡単な説明】
【図１】式ＩＩの化合物（ｎ＝１０、ｑ＝１）の核磁気共鳴スペクトル（ＮＭＲ）の図である。
【図２】式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝２、ｑ＝２）の核磁気共鳴スペクトル（ＮＭＲ）の図である。
【図３】式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝２、ｑ＝２）の質量スペクトル（マススペクトル）の図である。
【図４】式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝２、ｑ＝２）のＤＳＣチャート図である。
【図５】（Ａ）式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝２、ｑ＝２）の液晶の偏光顕微鏡写真である。
（Ｂ）式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝２、ｑ＝２）の液晶状態からの急冷により生じた結晶の１０日後の偏光顕微鏡写真である。
（Ｃ）式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝３、ｑ＝２）の液晶の偏光顕微鏡写真である。
（Ｄ）式Ｉの化合物（ｎ＝ｍ＝ｋ＝１０、ｐ＝３、ｑ＝２）の液晶状態からの急冷により生じた結晶の１０日後の偏光顕微鏡写真である。
【図６】炭素数１０のメチレン鎖（ｎ＝１０）の液晶二量体のＤＳＣチャート図である。[0001]
[Technical field to which the invention belongs]
The present invention relates to novel compounds. More specifically, the present invention relates to a novel biphenyl derivative oligomer and a production method thereof, a liquid crystal using these, and a liquid crystal having novel physical properties.
[0002]
[Prior art]
The alkyl-substituted product of 4-cyano-4′-hydroxybiphenyl is an important low-molecular liquid crystal (Liquid Crystal Dictionary, Japan Society for the Promotion of Science, Liquid Crystal Section, 1994, Baifukan, p252, Appendix Table 2-5; hereinafter referred to as Prior Art 1) . Synthesis of a liquid crystal dimer in which 4-cyano-4'-hydroxybiphenyl is reacted with a compound of formula IV and 4-cyano-4'-hydroxybiphenyl is linked by a methylene chain is known (J. W. et al. Emsley, GR Ruckhurst, GN Shilstone, and I. Sage, Mol. Cryst. Liq. Cryst. 1984, 102, pp 223-233;
[0003]
One liquid crystal compound such as 4,4′-dihydroxybiphenyl or 4,4′-dihydroxyazobenzene was inserted between the liquid crystal dimers in which 4-cyano-4′-hydroxybiphenyl of Prior Art 2 was linked by a methylene chain. The synthesis of liquid crystal trimers is known (Furya, K. Asahi and A. Abe, Polymer J., 1986, 18, pp 779-782; T. Ikeda, T. Miyamoto, S. Kurihara, M. Tsuk and M. Tsuk. Tezuka, Mol.Cryst.Liq.Cryst., 1990, 182B, pp357-371; C. T. Imurie and G. R. Kuckhurst, J. Mater.Chem., 1998, 8, pp. 1339-134; 3). Furthermore, the synthesis of a liquid crystal tetramer in which two azomethine structures are inserted as a liquid crystal compound between the liquid crystal dimers of Prior Art 2 is known (C. T. Imurie, D. Stewart, C. Remy, D. et al. W. Christie and R. Harding, J. Mater. Chem., 1999, 9, pp 2321-2335;
[0004]
[Problems to be solved by the invention]
However, the liquid crystal dimer of the prior art 2, the liquid crystal trimer of the prior art 3, and the liquid crystal tetramer of the prior art 4 only show liquid crystallinity similar to general low-molecular liquid crystals.
In prior art 3 and prior art 4, a biphenyl compound having a structure different from that of 4-cyano-4'-hydroxybiphenyl is inserted between liquid crystal dimers having 4-cyano-4'-hydroxybiphenyl bonded to the terminal. Was.
Furthermore, no liquid crystal of a multimer type more than a pure liquid crystal pentamer has been known so far.
[0005]
The present invention relates to a liquid crystal trimer inserted as a core part inside a liquid crystal oligomer by introducing 4′-hydroxy-4-biphenylcarboxylic acid having a dipole as an asymmetric molecule into 4-cyano-4′-hydroxybiphenyl. The object is to provide a novel, pure multimeric compound ranging from a liquid crystal heptamer to a liquid crystal heptamer, and to provide a pure liquid crystal oligomer having characteristic properties that are not found in conventional low molecular liquid crystal properties. .
[0006]
[Means for Solving the Problems]
As a result of diligent research, the present inventor has used 4-cyano-4′-hydroxybiphenyl as the core portion of the terminal liquid crystal structure and 4′-hydroxy-4-biphenylcarboxylic acid as the core portion in the liquid crystal structure. By synthesizing a novel liquid crystal oligomer of the compound of the formula I having 3 to 7 core parts, in which the core parts are connected by a methylene chain having 3 to 12 carbon atoms, and clarifying its physical properties The invention has been completed and the above problems have been solved.
[0007]
The liquid crystal as used in the present invention refers to a liquid crystal when the temperature of the compound is raised, a liquid crystal when mixed with another compound, or a liquid crystal when dissolved in a specific solvent.
[0008]
The liquid crystal oligomer which is a compound of the formula I referred to in the present invention refers to a molecule exhibiting liquid crystallinity in which a plurality of structures composed of a core part such as a biphenyl group and a flexible part such as a hydrocarbon chain are connected. The structure of a liquid crystal molecule is an elongated molecule generally composed of a core part and a flexible part, and a liquid crystal trimer in which three structures composed of the core part and a flexible part are connected to a liquid crystal oligomer. There are a liquid crystal tetramer, a 5-linked liquid crystal pentamer, a 6-connected liquid crystal hexamer, and a 7-connected liquid crystal heptamer, and these are collectively referred to as a liquid crystal oligomer.
[0009]
Thus, according to the present invention, 4-cyano-4′-hydroxybiphenyl or 4′-hydroxy-4-biphenylcarboxylic acid is linked by a methylene chain having 3 to 12 carbon atoms to form a compound of formula I, of formula II A compound of formula III is provided.
[0010]
[Chemical 6]

(Wherein p = 1, 2, 3; q = 0, 1, 2; n, m, k = 3-12)
[0011]
[Chemical 7]

(Where q = 1, 2, 3; n = 3-12)
[0012]
[Chemical 8]

(Wherein p = 1, 2; k, m = 3-12; X = halogen)
[0013]
The novel compounds of formula I and formula II of the present invention are liquid crystal oligomers composed of biphenyl derivatives having liquid crystallinity. A preferred embodiment of the liquid crystal oligomer of the present invention shows physical properties different from those of general low-molecular liquid crystals. As the liquid crystal oligomer becomes a multimeric liquid crystal oligomer, the enthalpy change of the clearing point from the liquid crystal to the liquid increases, In the liquid crystal oligomer, when the temperature is lowered from the liquid crystal state, the liquid crystal structure changes to the solid state while maintaining the liquid crystal structure, and a solid state that maintains the liquid crystal structure can be formed.
[0014]
Furthermore, the present invention relates to a process for producing the above-mentioned biphenyl derivative oligomer, wherein 4-cyano-4′-hydroxybiphenyl is substituted with formula IV.
[Chemical 9]

(Where n = 3 to 12; X is a halogen atom)
To synthesize a compound of formula V
Embedded image

(Where n = 3 to 12; X is a halogen atom)
Next, a compound of formula V and 4′-hydroxy-4-biphenylcarboxylic acid are reacted to synthesize a compound of formula II and a compound of formula I,
Reacting a compound of formula II with a compound of formula IV to synthesize a compound of formula III and a compound of formula I;
A process for preparing a compound of formula I according to claim 1 obtained by reacting a compound of formula II and a compound of formula III or a compound of formula II and a compound of formula V if necessary.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, the synthesis of the compound of formula I, the compound of formula II, the compound of formula III and the characteristics of the physical properties of the multimeric liquid crystal oligomer will be described.
[0016]
4-Cyano-4'-hydroxybiphenyl synthesized in the present invention, 4'-hydroxy-4-biphenylcarboxylic acid, a liquid crystal in which three liquid crystal structures which are compounds of the formula I consisting of methylene chains having 3 to 12 carbon atoms are connected Trimer, 4-linked liquid crystal tetramer, 5-connected liquid crystal pentamer, 6-connected liquid crystal hexamer, and 7-connected liquid crystal heptamer are all new compounds, and these new compounds The structure of was identified by means such as nuclear magnetic resonance spectrum (NMR), infrared absorption spectrum (IR), mass spectrum (mass spectrum), and elemental analysis.
[0017]
An equimolar amount of 4-cyano-4'-hydroxybiphenyl and α, ω-dibromoalkane of formula IV is dissolved in an organic solvent such as N, N-dimethylformamide, DMSO, and a base such as potassium carbonate is added for 12 to 24 hours. Stir at room temperature. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is dissolved in chloroform, and separated by silica gel column chromatography (developing solvent: mixed solvent of chloroform and hexane). A compound of formula V, for example α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) alkane and a liquid crystal dimer is obtained. In addition to α, ω-dibromoalkane, the same reaction occurs with α, ω-dichloroalkane and α, ω-diiodoalkane.
(Reaction Formula 1)
[0018]
Embedded image

(Where X is a halogen atom)
[0019]
Further, α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) alkane and liquid crystal can be obtained by changing the molar ratio of 4-cyano-4′-hydroxybiphenyl and a compound of formula IV such as α, ω-dibromoalkane. Dimer yield can be varied.
The yield of α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) alkane and liquid crystal dimer varies depending on the number of n.
[0020]
Equimolar amounts of α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) alkane and 4′-hydroxy-4-biphenylcarboxylic acid, which are products of reaction formula 1, are dissolved in N, N-dimethylformamide, Add equimolar potassium carbonate and stir for 15 hours at room temperature. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is dissolved in chloroform and separated by silica gel chromatography (developing solvent: chloroform or a mixed solvent of chloroform and methanol), and the compound of formula II (q = 1) And a liquid crystal trimer of formula I (n = m, p = 1, q = 0). It is confirmed by NMR and IR that the compound of formula II (q = 1) is not OH but COOH.
(Reaction Formula 2)
[0021]
Embedded image

[0022]
An equimolar amount of the compound of formula II (p = 1), which is the product of reaction formula 2, and α, ω-dibromoalkane of formula IV is dissolved in N, N-dimethylformamide, and equimolar amount of potassium carbonate is added for 15 hours at room temperature. Stir with. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is dissolved in chloroform and separated by silica gel chromatography (developing solvent: chloroform or a mixed solvent of chloroform and hexane), and the compound of formula III (p = 1) And a liquid crystal tetramer of formula I (n = k, p = 1, q = 1).
(Reaction Formula 3)
[0023]
Embedded image

[0024]
An equimolar amount of potassium carbonate is dissolved in an equimolar amount of the compound of formula III (p = 1, n = m) and 4′-hydroxy-4-biphenylcarboxylic acid, which is the product of reaction formula 3, in N, N-dimethylformamide. And stirred at room temperature for 15 hours. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is dissolved in chloroform, and separated by thin layer silica gel chromatography (developing solvent: a mixed solvent of chloroform and hexane or a mixed solvent of chloroform and methanol). (Q = 2) and a liquid crystal pentamer of formula I (n = m = k, p = 2, q = 1) are obtained.
(Reaction Formula 4)
[0025]
Embedded image

[0026]
An equimolar amount of the compound of formula II (p = 2), which is the product of reaction formula 4, and α, ω-dibromoalkane of formula IV is dissolved in N, N-dimethylformamide, and equimolar amount of potassium carbonate is added for 15 hours at room temperature. Stir with. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was dissolved in chloroform, separated by thin layer silica gel chromatography (developing solvent: a mixed solvent of chloroform and hexane or chloroform), and the compound of formula III (n = m, p = 3) and the liquid crystal hexamer of formula I (n = m = k, p = 2, q = 2).
(Reaction Formula 5)
[0027]
Embedded image

[0028]
An equimolar amount of the compound of formula III (n = m, p = 3) and 4′-hydroxy-4-biphenylcarboxylic acid, which is the product of reaction formula 5, is dissolved in N, N-dimethylformamide, and equimolar amount of potassium carbonate. And stirred at room temperature for 15 hours. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is dissolved in chloroform, separated by thin layer silica gel chromatography (developing solvent: a mixed solvent of chloroform and hexane or chloroform), and the compound of formula II (q = 3) and a liquid crystal heptamer of formula I (n = m = k, p = 3, q = 2).
(Reaction Formula 6)
[0029]
Embedded image

[0030]
In the above reaction formulas 3 to 6, the reaction can be performed between compounds having different numbers of methylene chains. This makes it possible to produce a variety of liquid crystal oligomers of the formula I with different physical properties by different combinations of methylene chains. The synthesis of liquid crystal trimers of formula I (p = 1, q = 0) having different numbers of methylene chains is carried out as reaction formula 7.
[0031]
The product of reaction formula 2, the compound of formula II with n methylene chains (p = 1) and α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) with m methylene chains Dissolve equimolar alkane in N, N-dimethylformamide, add equimolar potassium carbonate and stir for 15 hours at room temperature. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is separated by silica gel chromatography (developing solvent: mixed solvent of hexane and chloroform or chloroform), and the number of methylene chains is n as the product of reaction formula 7. A liquid crystal trimer of formula I consisting of m (p = 1, q = 0) is obtained.
[0032]
(Reaction Formula 7)
Embedded image

[0033]
The liquid crystal oligomer of the present invention is different from a polymer liquid crystal in that it is a pure molecule. The physical properties of the liquid crystal oligomer vary depending on the number of methylene chains. For example, in general, a pure low-molecular liquid crystal has a large melting point enthalpy change from crystal to liquid crystal and a small clear point enthalpy change from liquid crystal to liquid. The thermal behavior of the liquid crystal oligomer synthesized in the present invention is examined by using a polarizing microscope on a hot plate and / or a suggested scanning calorimeter (DSC). As a result, in the case of a multimeric liquid crystal oligomer having a large number of methylene chains and p and q in Formula I, the enthalpy change of the clearing point from the liquid crystal to the liquid is larger than the enthalpy change of the melting point. Since such physical properties do not occur in general low-molecular liquid crystals, the characteristics of pure multimeric liquid crystal oligomers have been found.
[0034]
Furthermore, in the case of a multimeric liquid crystal oligomer having a large number of methylene chains and p and q in the formula I, when the temperature is lowered from the liquid crystal state, it changes to a solid state with the liquid crystal structure maintained. This physical property is found in a liquid crystal oligomer having a methylene chain having 10 carbon atoms (n = m = k = 10), from a liquid crystal tetramer to a liquid crystal heptamer. This indicates that the solid state is crystallized while maintaining the structure of the liquid crystal state. This physical property is important in that it shows that the structure of the solid state can be controlled by manipulating the structure of the liquid crystal with fluidity, and is useful for designing new functional materials.
[0035]
【Example】
As an example, synthesis and properties of a liquid crystal heptamer from a liquid crystal trimer when n = m = k = 10, and a liquid crystal trimer consisting of n = 3 and m = 12 or n = 12 and m = 3 And n = k = 3 and m = 12, or n = k = 12, and m = 3. Examples of the present invention are shown below, but the present invention is not limited by these examples.
[0036]
Example 1: (Scheme 1, n = 10)
10 mmol of 4-cyano-4′-hydroxybiphenyl (manufactured by Aldrich, USA) and 10 mmol of 1,10-dibromodecane (special grade reagent, Wako Pure Chemical Industries, Ltd.), Dissolved in 200 ml, 10 mmol of potassium carbonate (special grade reagent, Nakarai Kogyo Co., Ltd.) was added and stirred at room temperature for 15 hours. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: mixed solvent of chloroform and hexane), and α-bromo-ω- (4 -Cyanobiphenyl-4'-yloxy) decane was obtained in a yield of 69%, and a liquid crystal dimer was obtained in a yield of 9%.
[0037]
Example 2: (Reaction formula 2, n = m = 10)
4 mmol of the product α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) decane and 4 mmol of 4′-hydroxy-4-biphenylcarboxylic acid (manufactured by Aldrich, USA) were added to N, N-dimethylformamide. After dissolving in 100 ml, 4 mmol of potassium carbonate was added and stirred at room temperature for 15 hours. The reaction solution was filtered, the solvent of the filtrate was distilled, and the residue was separated by thin layer silica gel chromatography (developing solvent: chloroform). As a product of reaction formula 2, a compound of formula II (n = 10, q = 1) was obtained in 47% yield and a liquid crystal trimer of formula I (n = m = 10, p = 1, q = 0). The yield was 14%. It was confirmed by NMR and IR that the end of the compound of formula II (n = 10, q = 1) was not OH but COOH. The NMR spectrum of the compound of formula II (n = 10, q = 1) is shown in FIG. From FIG. 1, no COOH peak was observed, and an OH peak (δ 5.23) was observed, confirming the compound of formula II.
[0038]
Example 3 (Scheme 3, n = m = k = 10)
2 mmol of the compound of formula II obtained in reaction formula 2 (n = 10, p = 1) and 2 mmol of 1,10-dibromodecane were dissolved in 50 ml of N, N-dimethylformamide, 2 mmol of potassium carbonate was added and stirred at room temperature for 15 hours. . The reaction solution is filtered, the solvent of the filtrate is distilled, and the residue is separated by thin-layer silica gel chromatography (developing solvent: 7: 3 mixed solvent of chloroform and hexane). Compound (n = m = 10, p = 1) was obtained in 56% yield, and liquid crystal tetramer of formula I (n = m = k = 10, p = 1, q = 1) was obtained in 15% yield. It was.
[0039]
Example 4 (Scheme 4, n = m = k = 10)
1 mmol of the compound of formula III (n = m = 10, p = 1) obtained in reaction formula 3 and 1 mmol of 4′-hydroxy-4-biphenylcarboxylic acid are dissolved in 50 ml of N, N-dimethylformamide, and 1 mmol of potassium carbonate is added. Stir for 15 hours at room temperature. The reaction solution is filtered, the solvent of the filtrate is distilled, and the residue is separated by thin-layer silica gel chromatography (developing solvent: 9: 1 mixed solvent of chloroform and hexane). The compound (n = 10, q = 2) was obtained in 53% yield, and the liquid crystal pentamer of formula I (n = m = k = 10, p = 2, q = 1) was obtained in 7% yield.
[0040]
Example 5 (Scheme 5, n = m = k = 10)
Dissolve 0.5 mmol of the compound of formula II obtained in reaction formula 4 (n = 10, p = 2) and 0.5 mmol of 1,10-dibromodecane in 50 ml of N, N-dimethylformamide, and add 0.5 mmol of potassium carbonate. Stir for 15 hours at room temperature. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by thin layer silica gel chromatography (developing solvent: chloroform), and the compound of formula III (n = m = 10, p) as the product of reaction formula 5 = 3) and a liquid crystal hexamer of formula I (n = m = k = 10, p = 2, q = 2) was obtained in a yield of 9%. FIG. 2 shows a nuclear magnetic resonance spectrum (NMR) and FIG. 3 shows a mass spectrum (mass spectrum) of this liquid crystal hexamer. From the mass spectrum, MNa ⁺ Is 1961, that is, the molecular weight of this molecule is 1961-23 (atomic weight of Na) = 1938. It was confirmed to be a hexamer of a biphenyl derivative.
[0041]
Example 7 (Scheme 6, n = m = k = 10)
The compound of formula III (n = m = 10, p = 3) (0.25 mmol) and 4′-hydroxy-4-biphenylcarboxylic acid (0.25 mmol), which is the product of reaction formula 5, are converted to N, N-dimethyl. Dissolved in formamide (20 ml), potassium carbonate (0.5 mmol) was added and stirred at room temperature for 15 hours. The reaction solution is filtered, the solvent of the filtrate is distilled, and the residue is separated by thin layer silica gel chromatography (developing solvent: mixed solvent of chloroform and hexane) to obtain the compound of formula II (n = 10, q = 3). A liquid crystal heptamer of formula I (n = m = k = 10, p = 3, q = 2) was obtained in 4% yield with a yield of 9%.
[0042]
Example 8: Change in calorific value of liquid crystal multimer of formula I (n = m = k = 10)
The calorimetric change of the liquid crystal multimer of the formula I (n = m = k = 10) was measured with a differential scanning calorimeter (DSC). The liquid crystal trimer of formula I (p = 1, q = 0) showed similar properties to the liquid crystals of prior art 1 and prior art 2, but the liquid crystal tetramer of formula I (p = 1, q = 1). ), The enthalpy change from the liquid crystal to the liquid became larger as the liquid crystal multimer was obtained, and in the liquid crystal hexamer of formula I (p = 2, q = 2), it became larger than the enthalpy change of the melting point.
[0043]
Example 9: Observation of a liquid crystal multimer of the formula I (n = m = k = 10) with a polarizing microscope
The phase structure in the thermal change of the liquid crystal multimer of the formula I (n = m = k = 10) was clarified by observation with a polarizing microscope on a hot plate. In the liquid crystal trimer of formula I (p = 1, q = 0), when the temperature of the isotropic liquid is lowered, a nematic phase appears, and when the temperature is further lowered, crystallization occurs. From the monomer (p = 1, q = 1) to the liquid crystal heptamer of formula I (p = 3, q = 2), the smectic A phase appears when the temperature of the isotropic liquid is lowered, and when the temperature is further lowered, the liquid crystal It changed into a solid state with the phase structure of. Table 1 shows the phase transition temperature and enthalpy change of the liquid crystal multimer of the formula I (n = m = k = 10). The temperature rise and fall were measured at 5 ° C./min.
[0044]
[Table 1]

The phase transition temperature and enthalpy change were performed using a sample which was heated at room temperature for 12 hours or more as it was after the molecule was heated to form an isotropic liquid and the temperature was lowered. Where K is solid, N is nematic liquid crystal, S _A Is smectic A liquid crystal, S _C Denotes a smectic C liquid crystal, and I denotes an isotropic liquid.
[0045]
Among the results in Table 1, the change in the calorific value of the liquid crystal hexamer of formula I (p = 2, q = 2) will be explained. The compound turned into a smectic phase at 139 ° C., and the enthalpy change at that time was 26 kJ / mol. When further heated, it changed to an isotropic liquid at 183 ° C., and the enthalpy change at that time was 33 kJ / mol. When the temperature of the isotropic liquid was lowered, it changed to a smectic phase at 179 ° C., and the enthalpy change at that time was 30 kJ / mol. When the temperature was further lowered, it changed to a solid at 133 ° C., and the enthalpy change at that time was 22 kJ / mol (see FIG. 4).
Thus, the enthalpy change from the liquid crystal to the liquid was large, and the liquid crystal hexamer was larger than the enthalpy change of the melting point. In this liquid crystal hexamer, when the temperature was lowered from the liquid crystal state, it changed to a solid at 129 ° C., but at that time, it changed to a solid state while maintaining the phase structure of the liquid crystal (see FIG. 5). Similarly, it can be seen that even in the liquid crystal heptamer, the solid state is a crystal while maintaining the structure of the liquid crystal state (see FIG. 5). The crystal structure of the liquid crystal oligomer while maintaining the structure of the liquid crystal state was stable for 10 days or more.
[0046]
Synthesis of a liquid crystal trimer consisting of n = 3 and m = 12 or n = 12 and m = 3 and a liquid crystal tetramer consisting of n = k = 3 and m = 12 or n = k = 12 and m = 3 The liquid crystal range will be described. The liquid crystal range was measured with a differential scanning calorimeter (DSC), and the temperature was raised and lowered at 5 ° C./min.
[0047]
Example 10: (Reaction Scheme 1, n = 3)
10 mmol of 4-cyano-4′-hydroxybiphenyl (manufactured by Aldrich, USA) and 10 mmol of 1,3-dibromopropane (special grade reagent, Wako Pure Chemical Industries, Ltd.), N, N-dimethylformamide (special grade reagent, Nacalai Industrial Co., Ltd.) Dissolved in 200 ml, 10 mmol of potassium carbonate (special grade reagent, Nakarai Kogyo Co., Ltd.) was added and stirred at room temperature for 15 hours. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: mixed solvent of chloroform and hexane), and α-bromo-ω- (4 -Cyanobiphenyl-4'-yloxy) propane was obtained in a yield of 48%, and a liquid crystal dimer was obtained in a yield of 7%.
[0048]
Example 11: (Reaction Scheme 2, n = m = 3)
4 mmol of the product α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) propane and 4 mmol of 4′-hydroxy-4-biphenylcarboxylic acid (manufactured by Aldrich, USA) were added to N, N-dimethylformamide. After dissolving in 100 ml, 4 mmol of potassium carbonate was added and stirred at room temperature for 15 hours. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: hexane and chloroform), and the compound of formula II (n = 3, q = 1) was obtained in a yield of 21% and a liquid crystal trimer of formula I (n = m = 3, p = 1, q = 0) was obtained in a yield of 9%. The liquid crystal range of the liquid crystal trimer of formula I (n = m = 3, p = 1, q = 0) was 186 ° C.-242 ° C. during the temperature rising process and 239 ° C.-120 ° C. during the temperature lowering process.
[0049]
Example 12: (Reaction Scheme 1, n = 12)
10 mmol of 4-cyano-4′-hydroxybiphenyl (manufactured by Aldrich, USA) and 10 mmol of 1,12-dibromododecane (manufactured by Aldrich, USA) were dissolved in 200 ml of N, N-dimethylformamide (special grade reagent, Nakarai Industrial Co., Ltd.) 10 mmol of potassium carbonate (special grade reagent Nacalai Kogyo Co., Ltd.) was added and stirred at room temperature for 15 hours. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: mixed solvent of chloroform and hexane), and α-bromo-ω- (4 -Cyanobiphenyl-4'-yloxy) dodecane was obtained in a yield of 55%, and a liquid crystal dimer was obtained in a yield of 12%.
[0050]
Example 13: (Reaction scheme 2, n = m = 12)
4 mmol of the product α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) dodecane and 4 mmol of 4′-hydroxy-4-biphenylcarboxylic acid (manufactured by Aldrich, USA) were added to N, N-dimethylformamide. After dissolving in 100 ml, 4 mmol of potassium carbonate was added and stirred at room temperature for 15 hours. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: hexane and chloroform), and the compound of formula II (n = 12, q = 1) A liquid crystal trimer of formula I (n = m = 12, p = 1, q = 0) was obtained in a yield of 8% with a yield of 38%. The liquid crystal range of the liquid crystal trimer of formula I (n = m = 12, p = 1, q = 0) was 151 ° C.-161 ° C. during the temperature rising process and 157 ° C.-113 ° C. during the temperature decreasing process.
[0051]
Example 14: (Reaction Scheme 7, n = 3, m = 12)
1 mmol of the compound of formula II (n = 3, p = 1) which is the product of Example 11 and 1 mmol of α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) dodecane which is the product of Example 12. Was dissolved in 50 ml of N, N-dimethylformamide, 1 mmol of potassium carbonate was added, and the mixture was stirred for 15 hours at room temperature. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is separated by silica gel column chromatography (developing solvent: hexane and chloroform), and the liquid crystal trimer of formula I (n = 3) is obtained as the product of reaction formula 7. , M = 12, p = 1, q = 0) with a yield of 32%. The liquid crystal temperature range of the liquid crystal trimer of formula I (n = 3, m = 12, p = 1, q = 0) is 161 ° C.-222 ° C. during the temperature rising process and 219 ° C.-96 ° C. during the temperature lowering process. there were.
[0052]
Example 15: (Reaction Scheme 7, n = 12, m = 3)
1 mmol of the compound of formula II (n = 12, p = 1) which is the product of Example 13 and mmol of α-bromo-ω- (4-cyanobiphenyl-4′-yloxy) propane which is the product of Example 12. Was dissolved in 50 ml of N, N-dimethylformamide, 1 mmol of potassium carbonate was added, and the mixture was stirred for 15 hours at room temperature. The reaction solution is filtered, the solvent of the filtrate is distilled, the residue is separated by silica gel column chromatography (developing solvent: hexane and chloroform), and the liquid crystal trimer of formula I (n = 12) is obtained as the product of reaction formula 7. , M = 3, p = 1, q = 0) with a yield of 25%. The liquid crystal temperature range of the liquid crystal trimer of formula I (n = 12, m = 3, p = 1, q = 0) was 138 ° C.-156 ° C. during the temperature rise process and 151 ° C.-80 ° C. during the temperature drop process. It was.
[0053]
Example 16: (Reaction scheme 3, n = k = 3, m = 12)
Dissolve 1 mmol of the compound of formula II (n = 3, p = 1) and 1 mmol of 1,12-dibromododecane in 50 ml of N, N-dimethylformamide and add 1 mmol of potassium carbonate for 15 hours at room temperature. Stir. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: hexane and chloroform), and the liquid crystal tetramer of formula I (n = k) as the product of reaction formula 8 = 3, m = 12, p = 1, q = 1) in 6% yield and the compound of formula III (n = 3, m = 12, p = 1) in 32% yield. The liquid crystal temperature range of the liquid crystal tetramer of formula I (n = k = 3, m = 12, p = 1, q = 1) is 124 ° C.-221 ° C. during the temperature rising process and 219 ° C.-66 during the temperature decreasing process. ° C. The range of the liquid crystal temperature of the compound of formula III (n = 3, m = 12, p = 1) was 126 ° C.-170 ° C. during the temperature rising process and 167 ° C.-97 ° C. during the temperature lowering process.
[0054]
Example 17: (Reaction scheme 3, n = k = 12, m = 3)
Dissolve 1 mmol of the compound of formula II (n = 12, p = 1) and 1 mmol of 1,3-dibromopropane in 50 ml of N, N-dimethylformamide and add 1 mmol of potassium carbonate for 15 hours at room temperature. Stir. The reaction solution was filtered, the solvent of the filtrate was distilled, the residue was separated by silica gel column chromatography (developing solvent: hexane and chloroform), and the liquid crystal tetramer of formula I (n = k) as the product of reaction formula 8 = 12, m = 3, p = 1, q = 1) in 4% yield and the compound of formula III (n = 12, m = 3, p = 1) in 30% yield. The liquid crystal temperature range of the liquid crystal tetramer of formula I (n = k = 12, m = 3, p = 1, q = 1) is 101 ° C.-147 ° C. during the temperature rising process, and 138 ° C.-92 during the temperature decreasing process. ° C. The range of the liquid crystal temperature of the compound of formula III (n = 12, m = 3, p = 1) was 89 ° C.-119 ° C. during the temperature rising process and 116 ° C.-57 ° C. during the temperature lowering process.
[0055]
Comparative Example 1: Phase transition of n = 10 liquid crystal dimer
The change in the calorific value of the liquid crystal dimer of methylene chain having 10 (n = 10) carbon atoms in prior art 2 was measured by a differential scanning calorimeter (DSC) and compared with the liquid crystal multimer of methylene chain having 10 carbon atoms. This liquid crystal dimer was obtained in Example 1. This liquid crystal dimer changed from a solid to a liquid crystal at 164 ° C., and the enthalpy change at that time was 38 kJ / mol. When the temperature was further increased, the liquid became an isotropic liquid at 182 ° C., and the enthalpy change at that time was 6 kJ / mol. When the temperature was lowered from the isotropic liquid, it changed to liquid crystal at 180 ° C., and the enthalpy change at that time was 6 kJ / mol. When the temperature was further lowered, it became a solid at 124 ° C., and the enthalpy change at that time was 37 kJ / mol. At this time, a crystal structure different from the liquid crystal structure was observed. A DSC chart of a methylene chain liquid crystal dimer having 10 carbon atoms is shown in FIG. Compared with the DSC chart of a liquid crystal hexamer with 10 carbon atoms in methylene chain (Figure 4), the enthalpy change from liquid crystal to isotropic liquid is small and the enthalpy change from liquid crystal to isotropic liquid is small. . On the other hand, multimer-type liquid crystal oligomers such as liquid crystal hexamers have a small enthalpy change from a liquid crystal dimer to a liquid crystal, and a large enthalpy change from a liquid crystal to an isotropic liquid. It turns out that it is a feature. In addition, it is understood that the liquid crystal structure changes to a solid state without changing, which is a feature of the multimeric liquid crystal oligomer.
[0056]
【The invention's effect】
As understood from the above description, the novel compound of the present invention uses 4-cyano-4′-hydroxybiphenyl as the terminal core moiety and is similar to 4-cyano-4′-hydroxybiphenyl as the inner core moiety. It is a pure oligomer molecule using 4′-hydroxy-4-biphenylcarboxylic acid, which is a non-target molecule, and having a core portion connected by a methylene chain having 3 to 12 carbon atoms.
The oligomer molecules exhibit liquid crystallinity and have characteristics different from general low-molecular liquid crystals. The liquid crystal oligomer of the present invention is different from a polymer liquid crystal in that it is a pure molecule.
The characteristic properties of the liquid crystal oligomer of the present invention are that, unlike general low-molecular liquid crystals, a large enthalpy change of the clearing point and that the liquid crystal structure is maintained as it is when the liquid crystal changes to a solid state. This is extremely useful in that the solid state structure can be controlled by manipulating the fluid liquid crystal structure.
[0057]
[Brief description of the drawings]
FIG. 1 is a nuclear magnetic resonance (NMR) diagram of a compound of formula II (n = 10, q = 1).
FIG. 2 is a nuclear magnetic resonance (NMR) spectrum of the compound of formula I (n = m = k = 10, p = 2, q = 2).
FIG. 3 is a diagram of the mass spectrum (mass spectrum) of a compound of formula I (n = m = k = 10, p = 2, q = 2).
FIG. 4 is a DSC chart of the compound of formula I (n = m = k = 10, p = 2, q = 2).
FIG. 5 is a polarizing micrograph of a liquid crystal of (A) a compound of formula I (n = m = k = 10, p = 2, q = 2).
(B) Polarization micrograph after 10 days of crystals formed by rapid cooling from the liquid crystal state of the compound of formula I (n = m = k = 10, p = 2, q = 2).
(C) Polarized micrograph of liquid crystal of compound of formula I (n = m = k = 10, p = 3, q = 2).
(D) Polarization micrograph after 10 days of a crystal formed by rapid cooling from a liquid crystal state of a compound of formula I (n = m = k = 10, p = 3, q = 2).
FIG. 6 is a DSC chart of a liquid crystal dimer of a methylene chain (n = 10) having 10 carbon atoms.

Claims (5)

Formula I

(Wherein p = 1, 2, 3; q = 0, 1, 2; n, m, k = 3-12)
A biphenyl derivative oligomer represented by Formula II

(Where q = 1, 2, 3; n = 3-12)
A biphenyl derivative oligomer represented by Formula III

(Wherein p = 1, 2; n, m = 3-12; X = halogen)
A biphenyl derivative oligomer represented by   A liquid crystal comprising at least one biphenyl derivative oligomer according to any one of claims 1 to 3. 4-Cyano-4'-hydroxybiphenyl is converted to formula IV

(Where n = 3 to 12; X is a halogen atom)
To synthesize a compound of formula V

(Where n = 3 to 12; X is a halogen atom)
Next, a compound of formula V and 4′-hydroxy-4-biphenylcarboxylic acid are reacted to synthesize a compound of formula II and a compound of formula I,
Reacting a compound of formula II with a compound of formula IV to synthesize a compound of formula III and a compound of formula I;
A process for preparing a compound of formula I according to claim 1 obtained by reacting a compound of formula II and a compound of formula III or a compound of formula II and a compound of formula V if necessary.

Images