JP3859312B2 - Optical recording material - Google Patents

Description

（式中、Ａはニトロ基、Ｂは炭素原子数１〜８のアルキル基、ハロゲン原子、ニトリル基、またはニトロ基を示し、Ｒ₁ およびＲ ₂ は各々独立に炭素原子数１〜８のアルキル基、または基−（Ｙ−Ｏ）_q −Ｒ₃ −Ｚ（Ｙは炭素原子数２〜４のアルキレン基を示し、Ｒ₃ は炭素原子数１〜２０の二価の炭化水素基を示し、Ｚは水素原子またはハロゲン原子を示す。）を示し、Ｘは−Ｃ（ＣＨ₃ ）₂ −を示し、Ａｎ^- はアニオンを示し、ｐは１、ｑは１を示す。）
【００１９】
【発明の実施の形態】
以下、本発明の光学記録材料について詳細に説明する。
【００２０】
本発明に係る上記一般式（Ｉ）で表される化合物は、光学記録媒体の記録層に使用される色素である。
上記一般式（Ｉ）で表される化合物において、Ｂ、Ｒ₁ 、Ｒ ₂ で表される炭素原子数１〜８のアルキル基としては、メチル、エチル、プロピル、イソプロピル、ブチル、第二ブチル、第三ブチル、イソブチル、アミル、イソアミル、第三アミル、ヘキシル、ヘプチル、オクチル、イソオクチル、第三オクチル、２−エチルヘキシル等があげられ、Ｙで表される炭素原子数２〜４のアルキレン基としては、例えば、エチレン、プロピレン、ブチレンなどの直鎖あるいは分岐のアルキレン基があげられる。ＢおよびＺで表されるハロゲン原子としては、弗素、塩素、臭素、沃素などがあげられる。
【００２１】
R₃で表される炭素原子数１〜２０の二価の炭化水素基としては、二価の脂肪族基あるいは芳香族基であり、例えば、二価の脂肪族基としては、メチレン、エチレン、プロピレン、ブチレン、ペンチレン、ヘキシレン、ヘプチレン、オクチレン、ノニレン、デシレン、ウンデシレン、ドデシレン、トリデシレン、テトラデシレン、ペンタデシレン、ヘキサデシレン、ヘプタデシレン、オクタデシレン、ノナデシレン、エイコシレンなどの直鎖あるいは分岐のアルキレン基があげられ、これらは分子中に不飽和結合あるいは環状構造を有してもよく、二価の芳香族基としては、例えば、フェニレン、ナフチレンなどの基があげられ、これらは置換基を有してもよく、さらに一種以上のアルキレン基と一種以上の芳香族基が相互に結合したものであってもよいが、特に炭素原子数１〜１０のアルキレン基であるものが溶剤への溶解性に一層優れるため好ましい。
【００２２】
また、Ｘは−Ｃ（ＣＨ₃ ）₂ −を表し、Ｘが−Ｃ（ＣＨ₃ ）₂ −であるものが溶剤への溶解性に優れる。
【００２３】
さらに、An^-で表されるアニオンとしては、例えば、塩素アニオン、臭素アニオン、沃素アニオン、弗素アニオン等のハロゲンアニオン；過塩素酸アニオン、チオシアン酸アニオン、六フッ化リンアニオン、六フッ化アンチモンアニオン、四フッ化硼素アニオンなどの無機系アニオン、または、ベンゼンスルホン酸アニオン、トルエンスルホン酸アニオン、トリフルオロメタンスルホン酸アニオン等の有機スルホン酸アニオン；オクチルリン酸アニオン、ドデシルリン酸アニオン、オクタデシルリン酸アニオン、フェニルリン酸アニオン、ノニルフェニルリン酸アニオン等の有機リン酸アニオンなどの有機系アニオン、あるいは、例えば、クエンチャーアニオンとして、特開昭６０−２３４８９２号公報に記載されたようなものがあげられる。該クエンチャーアニオンの代表例としては、下記〔化３〕の一般式（Ａ）および（Ｂ）で表されるアニオンがあげられる。
【００２４】
【化３】

【００２５】
また、ｐは１を示し、ｐが１である化合物が、書き込みおよび再生の６２０〜６９０ｎｍの波長に対して感度に優れる。
【００２６】
上記一般式（Ｉ）で表される化合物の代表例としては、下記〔化４〕〜〔化１０〕に示すΦ−１〜Φ−７などが挙げられる。尚、以下の例示では、アニオンを省いたシアニン色素カチオンで示している。
【００２７】
【化４】

【００２８】
【化５】

【００２９】
【化６】

【００３０】
【化７】

【００３１】
【化８】

【００３２】
【化９】

【００３３】
【化１０】

【００３４】
これらの化合物の中でも、特に、Ｂがニトリル基である化合物、またはＢがニトロ基である化合物が分子吸光係数が大きく好ましい。
【００３５】
上記一般式（Ｉ）で表される化合物からなる本発明の光学記録材料は、上記シアニン色素カチオンとアニオンとの塩であり、従来周知の方法に準じて製造することができる。
【００３６】
次に、上記一般式（Ｉ）で表される化合物の具体的な合成例を挙げる。
【００３７】
合成例１
１，１’−ジイソアミル−３，３，３’，３’−テトラメチル−５−ニトロ−５−シアノ−インドレニン−２−トリメチンシアニン過塩素酸塩（Φ−１の過塩素酸塩）の製造
【００３８】
上記色素の半量体である１−イソアミル−２−〔２−アニリノ−エテン（１）−イル〕−３，３−ジメチル−５−ニトロインドレニン過塩素酸塩を次のように合成した。
【００３９】
温度計、冷却管、窒素導入管つき丸底２００ｍｌフラスコに１−イソアミル−２，３，３−トリメチル−５−ニトロインドレニン過塩素酸塩（Mw=374）３７．４ｇとＮ，Ｎ’−ジフェニルホルムアミジン（Mw=196）２１．６ｇとを加え、ピリジン７９ｇを溶媒として窒素気流下、１１６℃で２時間反応させた。反応終了後、ピリジンを脱溶媒除去しアセトン２００ｇに溶解した後２００ｇのシリカゲルに吸着させ乾燥した。これを２ｋｇシリカゲルを充填したカラム上部に仕込み、酢酸エチル─ヘキサンの混合溶媒を展開液としてカラム分離したところ目的物３６ｇ（収率７６％）を得た。
【００４０】
次に、得られた１−イソアミル−２−〔２−アニリノ−エテン（１）−イル〕−３，３−ジメチル−５−ニトロインドレニン 過塩素酸塩（Mw=477）１４．３ｇと１−イソアミル−２，３，３−トリメチル−５−シアノインドレニン 過塩素酸塩（Mw=354）１１．２ｇを２００ｍｌ丸底フラスコに仕込み、ピリジン４７．４ｇを溶媒として１１６℃で２時間反応させた後、無水酢酸（Mw=102）３．１ｇを加えさらに１１６℃で１時間反応した。反応終了後上記と同様にしてカラム分離を行い、目的物１６ｇ（収率７２％）を得た。λ_max ＝５７５ｎｍ（クロロホルム溶液、以下同じ）ε＝２．１０×１０⁵ であった。
【００４１】
合成例２
１，１’−ジｎ−プロピル−３，３，３’，３’−テトラメチル−５−ニトロ−５’−クロロインドレニン−２−トリメチレンシアニン過塩素酸塩（Φ−２の過塩素酸塩）の製造
【００４２】
合成例１と同様にして、半量体である１−ｎ−プロピル−２−〔２−アニリノ−エテン（１）−イル〕−３，３−ジメチル−５−ニトロインドレニン 過塩素酸塩を一旦合成し、つぎに１−ｎ−プロピル−２，３，３−トリメチル−５−クロロ−インドレニン 過塩素酸塩と反応させて合成した。λ_max ＝５７４ｎｍ、ε＝１．７９×１０⁵ であった。
【００４３】
合成例３〜５
置換基が、Φ−３からΦ−５の構造式に対応する原料を用いる以外は合成例１と同様に行い、下記に示す化合物を合成した。
【００４４】
１，１’−ジｎ−ブチル−３，３，３’，３’−テトラメチル−５−ニトロ−５’−ブロモインドレニン−２−トリメチレンシアニン過塩素酸塩（Φ−３の過塩素酸塩）
λ_max = ５７６nm，ε= １．８１×１０⁵
【００４５】
１−ｎ−ブチル−１’−ｎ−プロピル−３，３，３’，３’−テトラメチル−５−ニトロ−５’−メチルインドレニン−２−トリメチレンシアニン過塩素酸塩（Φ−４の過塩素酸塩）
λ_max = ５７４nm，ε= １．７５×１０⁵
【００４６】
１−イソアミル−１’−〔１−（２−フェノキシ）エチル〕−３，３，３’，３’−テトラメチル−５，５’−ジニトロインドレニン−２−トリメチレンシアニン過塩素酸塩（Φ−５の過塩素酸塩）
λ_max = ５８１nm，ε= １．９５×１０⁵
【００４７】
合成例６
１，１’−ジ〔１−（２−フェノキシ）エチル〕−３，３，３’，３’−テトラメチル−５，５’−ジニトロインドレニン−２−トリメチレンシアニン過塩素酸塩（Φ−６の過塩素酸塩）の製造
【００４８】
温度計、冷却管、窒素導入管つき丸底５００ｍｌフラスコに１−〔１−（２−フェノキシ）エチル〕−２，３，３−トリメチル−５−ニトロインドレニン過塩素酸塩（Mw=424）１２７ｇとオルトギ酸トリメチル（MW=142) ２２．７ｇとを加え、ピリジン２８４ｇを溶媒として窒素気流下、１００℃まで１時間で昇温し、その後１１０℃で加熱還流を２時間行った。さらに分水器を取りつけ、生成するエタノール除きながら、１１５℃で加熱還流を２時間行った。反応終了後ピリジンを留去し、メタノール８０ｇを加え加熱溶解し、蒸留水８０ｇを５０℃において１時間で滴下した。２時間攪拌後、２０℃でろ過し、乾燥して８１ｇの目的物を得た。収率７１％、λ_max ＝５８３ｎｍ、ε＝１．９９×１０⁵ であった。
【００４９】
合成例７
１，１’−ジイソアミル−３，３，３’，３’−テトラメチル−５，５’−ジニトロインドレニン−２−トリメチレンシアニン過塩素酸塩（Φ−７の過塩素酸塩）の製造
【００５０】
合成例６の１−〔１−（２−フェノキシ）エチル〕−２，３，３−トリメチル−５−ニトロインドレニン過塩素酸塩のかわりに、１−イソアミル−２，３，３−トリメチル−５−ニトロインドレニン過塩素酸塩（Mw=374）１１２ｇを用いる以外は同様に反応を行い、目的物７６ｇを得た。収率７７％、λ_max = ５８２nm，ε= ２．０９×１０⁵ であった。
【００５１】
本発明の光学記録材料は、光学記録媒体の記録層として適用され、その形成にあたっては従来周知の方法を用いることができる。一般には、メタノール、エタノール等の低級アルコール類、メチルセルソルブ、エチルセルソルブ、ブチルセルソルブ、ブチルジグリコール等のエーテルアルコール類、アセトン、メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン、ジアセトンアルコール等のケトン類、酢酸エチル、酢酸ブチル、酢酸メトキシエチル等のエステル類、アクリル酸エチル、アクリル酸ブチル等のアクリル酸エステル類、２，２，３，３−テトラフルオロプロパノール等のフッ化アルコール類、ベンゼン、トルエン、キシレン等の炭化水素類、メチレンジクロライド、ジクロロエタン、クロロホルム等の塩素化炭化水素類等の有機溶媒に溶解した溶液を基体上に塗布することによって容易に形成することができる。
【００５２】
上記記録層の厚さは、通常、０．００１〜１０μであり、好ましくは０．０１〜５μの範囲が適当である。上記記録層の形成方法は特に制限を受けず、例えばスピンコート法等の通常の方法を用いることができる。
【００５３】
本発明の光学記録材料を、光学記録媒体の記録層に含有させる際の該記録層に対する使用量は、好ましくは５０〜１００重量％である。
【００５４】
また、上記記録層は、本発明の光学記録材料の他に、必要に応じて、ポリエチレン、ポリエステル、ポリスチレン、ポリカーボネート等の樹脂類を含有してもよく、界面活性剤、帯電防止剤、滑剤、難燃剤、安定剤、分散剤、酸化防止剤、架橋剤等を含有してもよい。
【００５５】
更に、上記記録層は、一重項酸素等のクエンチャーとして芳香族ニトロソ化合物、遷移金属キレート化合物等を含有してもよい。これらの化合物としては、例えば、特開昭５９−５５７９５公報に提案されているような公知の化合物が用いられる。該化合物は、記録層に対して好ましくは０〜５０重量％の範囲で使用される。
【００５６】
このような記録層を設層する上記基体の材質は、書き込み光及び読み出し光に対して実質的に透明なものであれば特に制限はなく、例えば、ポリメチルメタクリレート、ポリエチレンテレフタレート、ポリカーボネート等の樹脂、ガラス等が用いられる。また、その形状は、用途に応じ、テープ、ドラム、ベルト等の任意の形状のものが使用できる。
【００５７】
また、上記記録層上に、金、銀、アルミニウム、銅などを用いて蒸着法あるいはスパッタリング法により反射膜を形成させることもできるし、アクリル樹脂、紫外線硬化樹脂等による保護層を形成すこともできる。
【００５８】
本発明の光学記録材料は、ＬＤ、ＣＤ、ＤＶＤ、ＣＤ−Ｒ、ＤＶＤ−Ｒ等の光ディスク用の色素として使用することができ、特に書き込み再生に６２０〜６９０ｎｍの波長の光を用いるＤＶＤ−Ｒに好適である。
【００５９】
【実施例】
以下、実施例によって本発明を更に詳細に説明する。しかしながら、本発明は下記の実施例によって制限を受けるものではない。
【００６０】
実施例１
チタンキレート化合物（Ｔ−５０：日本曹達社製）を塗布、加水分解して下地層（０．０１μ) を設けた直径１２cmのポリカーボネートディスク基板上に、下記〔表１〕に示す色素及び芳香族ニトロソ化合物（ＤＱ−２４：旭電化工業（株）製）の１：０．１（重量比）のエチルセルソルブ溶液をスピンコーティング法にて塗布して、厚さ１００ｎｍの記録層を形成した。
【００６１】
さらに、記録層上に１００ｎｍの金の反射膜を蒸着法により形成した。
【００６２】
このようにして作成した各媒体を、３．６ｍ／ｓで回転させながら半導体レーザー (６３５nm、集光部出力７mW、周波数２KHz)を用いて基板裏面側から書き込みを行った。
【００６３】
次いで、半導体レーザー (６５０nm、集光部出力０．１mW) を読み出し光とし、基板をとおしての反射光を検出してスペクトラムアナライザーにて、バンド巾３０KHz でＣ／Ｎ比を測定した。
【００６４】
また、０．１mWのレーザーを読み出し光とし、１μ秒巾、３KHz のパルスとして、静止状態で５分間照射した後及び４０℃、相対湿度８８％の条件下に２５００時間保存した後の、基体裏面側からの反射率の変化（％）を測定した。
【００６５】
それらの結果を下記〔表１〕に示す。
【００６６】
【表１】

【００６７】
【化１１】

【００６８】
【化１２】

【００６９】
実施例２
下記〔表２〕に示す色素を用いて実施例１と同様に各媒体を作成し、分光エリプソメーター（Ｍ−１５０、日本分光（株）製）を用いて屈折率（ｎ）と消衰係数（ｋ）を測定した。それらの結果を下記〔表２〕に示す。
【００７０】
【表２】

【００７１】
上記実施例から明らかなように、本発明に係る前記一般式（Ｉ）で表される化合物（ニトロ基を有するシアニン色素）を用いた場合（実施例１−１〜１−９、２−１〜２−９）は、従来のシアニン色素を用いた場合（比較例１−１、１−２、２−１、２−２）と比較して、書き込み感度に優れ、照射後及び保存後の反射率の低下が著しく小さく、またｎとｋのバランスが優れることから、極めて信頼性の高い記録が可能となる。
【００７２】
【発明の効果】
本発明の光学記録材料は、光安定性、保存安定性及び溶媒への溶解性が良好であり、且つ感度の高いものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical recording material used for an optical recording medium for recording information by applying information as a thermal information pattern by a laser or the like. Specifically, the optical recording material has a wavelength in the visible and near-infrared region and has a low energy. The present invention relates to an optical recording material used for an optical recording medium capable of high-density optical recording and reproduction by a laser or the like.
[0002]
[Prior art and problems to be solved by the invention]
In general, the optical recording medium has a feature that the recording medium does not wear and deteriorate because the recording head does not contact the writing or reading head. In particular, the optical recording medium that gives information as thermal information is not developed in a dark room. Its development has been active because it has the advantage of being unnecessary.
[0003]
Such an optical recording medium uses recording light as heat. For example, information is recorded at high density by forming optically detectable pits on a thin recording layer provided on a substrate. be able to.
[0004]
Information is written on the recording medium by scanning a laser focused on the surface of the recording layer and forming pits in the recording layer that has absorbed the irradiated laser energy. In the information recorded on this recording medium, formed pits can be detected by reading light.
[0005]
As the recording layer of such an optical recording medium, an inorganic substance such as a metal thin film such as an aluminum vapor deposition film, a tellurium oxide thin film, a bismuth thin film or a chalcogenide amorphous glass film has been mainly used so far.
[0006]
These thin films are difficult to form by a coating method and need to be formed by sputtering or vacuum vapor deposition, but this method has a drawback that the operation is complicated. Moreover, the use of the above-described inorganic substances has drawbacks such as high reflectivity for laser light, high thermal conductivity, and low utilization of laser light.
[0007]
Therefore, a method has been proposed in which an organic compound mainly composed of a dye as an optical recording material, which can form pits with a semiconductor laser, instead of an inorganic substance, is used as a recording layer.
[0008]
As these dyes, for example, cyanine dyes such as indolenine, thiazole, imidazole, oxazole, quinoline, and selenazole are known. These dyes are salts of cyanine dye cations with various anions such as halogen anions and perchlorate anions. In particular, indolenine dyes are preferably used because of their high sensitivity.
[0009]
An optical recording medium (CD-R) that can be written and reproduced by a near-infrared semiconductor laser having a wavelength of 770 to 830 nm corresponding to the compact disc (CD) standard has been put to practical use as an optical storage medium using such a dye. Yes.
[0010]
Recently, a red semiconductor laser with a wavelength of 620 to 690 nm shorter than 770 nm has been developed, and the recording density is increased by making the beam spot smaller, and the moving image can be stored using data compression technology. Capacitive optical recording media (digital versatility discs, DVDs) are also in practical use.
[0011]
The present invention relates to a cyanine dye that is optimal for an optical recording medium (DVD-R) that can be additionally recorded or recorded, in conformity with the DVD standard.
[0012]
For example, a dye used for an optical recording medium that performs writing at 635 nm and uses a wavelength of 650 nm for reading has sensitivity for writing at 635 nm and has a high reflectance at 650 nm, that is, a large molecular extinction coefficient. Things are desirable.
[0013]
For example, Japanese Patent Application Laid-Open No. 59-55795 has proposed an optical recording medium using an indocarbocyanine dye in the recording layer as a dye compatible with writing with a red semiconductor laser of 620 to 690 nm.
[0014]
However, it cannot be said that these dyes exactly match the absorption wavelength of the above-mentioned DVD-R standard, and the reflectance is not sufficient.
[0015]
Accordingly, an object of the present invention is to provide an optical recording material that is used for a recording layer of an optical recording medium, has good light stability, storage stability, and solubility in a solvent, and has high sensitivity. Objective.
[0016]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that a compound in which a specific substituent is added to an indolenine cyanine dye can achieve the above object.
[0017]
The present invention has been made on the basis of the above knowledge, and comprises an optical recording material comprising a compound represented by the following general formula (I): It is to provide.
[0018]
[Chemical 2]

(In the formula, A represents a nitro group, B represents an alkyl group having 1 to 8 carbon atoms, a halogen atom, a nitrile group, or a nitro group , and R ₁ and R ₂ each independently represents an alkyl having 1 to 8 carbon atoms. group or a _{group, - (Y-O) q} -R 3 -Z (Y represents an alkylene group having 2 to 4 carbon atoms, R ₃ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, Z represents a a hydrogen atom or a halogen atom), X is -C (CH _{3) 2} -. indicates, an ^- represents an anion, p is 1, q is 1).
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the optical recording material of the present invention will be described in detail.
[0020]
The compound represented by the general formula (I) according to the present invention is a dye used for the recording layer of an optical recording medium.
In the compound represented by the general formula (I), B, the alkyl group of R _1, carbon atom number of 1 to 8, represented by R _2, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, Tertiary butyl, isobutyl, amyl, isoamyl, tertiary amyl, hexyl, heptyl, octyl, isooctyl, tertiary octyl, 2-ethylhexyl and the like. Examples of the alkylene group having 2 to 4 carbon atoms represented by Y include Examples thereof include linear or branched alkylene groups such as ethylene, propylene and butylene . Examples of the halogen atom represented by B and Z include fluorine, chlorine, bromine and iodine.
[0021]
The divalent hydrocarbon group having 1 to 20 carbon atoms represented by R ₃ is a divalent aliphatic group or an aromatic group. Examples of the divalent aliphatic group include methylene, ethylene, And linear or branched alkylene groups such as propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, octadecylene, nonadecylene, and eicosylene. The molecule may have an unsaturated bond or a cyclic structure, and examples of the divalent aromatic group include groups such as phenylene and naphthylene, which may have a substituent, and The above alkylene group and one or more aromatic groups are bonded to each other. May be but is preferable since those are more excellent in solubility in solvent in particular is an alkylene group having 1 to 10 carbon atoms.
[0022]
Also, X is -C (CH _{3) 2} - represents, X is -C (CH _{3) 2} - and which ones Ru excellent solubility in solvents.
[0023]
Furthermore, examples of the anion represented by An ⁻ include halogen anions such as chlorine anion, bromine anion, iodine anion, and fluorine anion; perchlorate anion, thiocyanate anion, phosphorus hexafluoride anion, and antimony hexafluoride anion. , Inorganic anions such as boron tetrafluoride anion, or organic sulfonate anions such as benzenesulfonate anion, toluenesulfonate anion, trifluoromethanesulfonate anion; octyl phosphate anion, dodecyl phosphate anion, octadecyl phosphate anion, Examples of organic anions such as organic phosphate anions such as phenyl phosphate anion and nonylphenyl phosphate anion, and quencher anions include those described in JP-A-60-234892. Representative examples of the quencher anion include anions represented by the following general formulas (A) and (B):
[0024]
[Chemical 3]

[0025]
Further, p represents 1, compound p is 1, Ru excellent sensitivity to the wavelength of the write and playback 620～690Nm.
[0026]
Typical examples of the compound represented by the general formula (I) include Φ-1 to Φ-7 shown in the following [Chemical Formula 4] to [Chemical Formula 10]. In the following examples, cyanine dye cations are used with the anions omitted.
[0027]
[Formula 4]

[0028]
[Chemical formula 5]

[0029]
[Chemical 6]

[0030]
[Chemical 7]

[0031]
[Chemical 8]

[0032]
[Chemical 9]

[0033]
[Chemical Formula 10]

[0034]
Among these compounds, a compound in which B is a nitrile group or a compound in which B is a nitro group is particularly preferable because of its large molecular extinction coefficient.
[0035]
The optical recording material of the present invention comprising the compound represented by the general formula (I) is a salt of the cyanine dye cation and anion and can be produced according to a conventionally known method.
[0036]
Next, specific synthesis examples of the compound represented by the general formula (I) will be given.
[0037]
Synthesis example 1
1,1′-Diisoamyl-3,3,3 ′, 3′-tetramethyl-5-nitro-5-cyano-indolenin-2-trimethine cyanine perchlorate (Φ-1 perchlorate) Manufacturing [0038]
1-isoamyl-2- [2-anilino-ethene (1) -yl] -3,3-dimethyl-5-nitroindolenine perchlorate, which is a half-mer of the above dye, was synthesized as follows.
[0039]
37.4 g of 1-isoamyl-2,3,3-trimethyl-5-nitroindolenine perchlorate (Mw = 374) and N, N′- in a round bottom 200 ml flask with a thermometer, a cooling tube and a nitrogen introduction tube 21.6 g of diphenylformamidine (Mw = 196) was added, and the reaction was carried out at 116 ° C. for 2 hours under a nitrogen stream using 79 g of pyridine as a solvent. After completion of the reaction, pyridine was removed from the solvent, dissolved in 200 g of acetone, adsorbed on 200 g of silica gel and dried. This was charged into the upper part of a column packed with 2 kg of silica gel and subjected to column separation using a mixed solvent of ethyl acetate and hexane as a developing solution to obtain 36 g of the desired product (yield 76%).
[0040]
Next, 14.3 g of 1-isoamyl-2- [2-anilino-ethene (1) -yl] -3,3-dimethyl-5-nitroindolenine perchlorate (Mw = 477) obtained and 1 -11.2 g of isoamyl-2,3,3-trimethyl-5-cyanoindolenine perchlorate (Mw = 354) was charged into a 200 ml round bottom flask and reacted at 116 ° C. for 2 hours using 47.4 g of pyridine as a solvent. Thereafter, 3.1 g of acetic anhydride (Mw = 102) was added, and the mixture was further reacted at 116 ° C. for 1 hour. After completion of the reaction, column separation was performed in the same manner as above to obtain 16 g (yield 72%) of the target product. λ _max = 575 nm (chloroform solution, the same applies hereinafter) ε = 2.10 × 10 ⁵ .
[0041]
Synthesis example 2
1,1′-Di-n-propyl-3,3,3 ′, 3′-tetramethyl-5-nitro-5′-chloroindolenine-2-trimethylene cyanine perchlorate (Φ-2 perchlorate Acid salt) [0042]
In the same manner as in Synthesis Example 1, 1-n-propyl-2- [2-anilino-ethene (1) -yl] -3,3-dimethyl-5-nitroindolenine perchlorate, which is a half-mer, was once added. And then reacted with 1-n-propyl-2,3,3-trimethyl-5-chloro-indolenine perchlorate. λ _max = 574 nm and ε = 1.79 × 10 ⁵ .
[0043]
Synthesis Examples 3-5
The compounds shown below were synthesized in the same manner as in Synthesis Example 1 except that the raw material corresponding to the structural formula of Φ-3 to Φ-5 was used as the substituent.
[0044]
1,1′-di-n-butyl-3,3,3 ′, 3′-tetramethyl-5-nitro-5′-bromoindolenine-2-trimethylene cyanine perchlorate (Φ-3 perchlorate) Acid salt)
λ _max = 576 nm, ε = 1.81 × 10 ⁵
[0045]
1-n-butyl-1′-n-propyl-3,3,3 ′, 3′-tetramethyl-5-nitro-5′-methylindolenine-2-trimethylene cyanine perchlorate (Φ-4 Perchlorate)
λ _max = 574 nm, ε = 1.75 × 10 ⁵
[0046]
1-isoamyl-1 ′-[1- (2-phenoxy) ethyl] -3,3,3 ′, 3′-tetramethyl-5,5′-dinitroindolenin-2-trimethylene cyanine perchlorate ( Φ-5 perchlorate)
λ _max = 581 nm, ε = 1.95 × 10 ⁵
[0047]
Synthesis Example 6
1,1′-di [1- (2-phenoxy) ethyl] -3,3,3 ′, 3′-tetramethyl-5,5′-dinitroindolenin-2-trimethylene cyanine perchlorate (Φ -6 perchlorate)
1- [1- (2-phenoxy) ethyl] -2,3,3-trimethyl-5-nitroindolenine perchlorate (Mw = 424) in a round bottom 500 ml flask with thermometer, condenser and nitrogen inlet 127 g and 22.7 g of trimethyl orthoformate (MW = 142) were added, and 284 g of pyridine was used as a solvent, and the temperature was raised to 100 ° C. over 1 hour in a nitrogen stream, followed by heating to reflux at 110 ° C. for 2 hours. Further, a water separator was attached, and refluxing was performed at 115 ° C. for 2 hours while removing the produced ethanol. After completion of the reaction, pyridine was distilled off, 80 g of methanol was added and dissolved by heating, and 80 g of distilled water was added dropwise at 50 ° C. over 1 hour. After stirring for 2 hours, it was filtered at 20 ° C. and dried to obtain 81 g of the desired product. The yield was 71%, λ _max = 583 nm, and ε = 1.99 × 10 ⁵ .
[0049]
Synthesis example 7
Preparation of 1,1'-diisoamyl-3,3,3 ', 3'-tetramethyl-5,5'-dinitroindolenin-2-trimethylene cyanine perchlorate (Φ-7 perchlorate) [0050]
Instead of 1- [1- (2-phenoxy) ethyl] -2,3,3-trimethyl-5-nitroindolenine perchlorate in Synthesis Example 6, 1-isoamyl-2,3,3-trimethyl- The reaction was conducted in the same manner except that 112 g of 5-nitroindolenine perchlorate (Mw = 374) was used to obtain 76 g of the desired product. The yield was 77%, λ _max = 582 nm, and ε = 2.09 × 10 ⁵ .
[0051]
The optical recording material of the present invention is applied as a recording layer of an optical recording medium, and conventionally known methods can be used for forming the recording layer. Generally, lower alcohols such as methanol and ethanol, ether alcohols such as methyl cellosolve, ethyl cellosolve, butyl cellosolve and butyl diglycol, and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and diacetone alcohol , Esters such as ethyl acetate, butyl acetate and methoxyethyl acetate, acrylic acid esters such as ethyl acrylate and butyl acrylate, fluorinated alcohols such as 2,2,3,3-tetrafluoropropanol, benzene and toluene It can be easily formed by applying a solution dissolved in an organic solvent such as hydrocarbons such as xylene, chlorinated hydrocarbons such as methylene dichloride, dichloroethane and chloroform onto the substrate.
[0052]
The thickness of the recording layer is usually 0.001 to 10 [mu], preferably 0.01 to 5 [mu]. The method for forming the recording layer is not particularly limited, and a normal method such as a spin coating method can be used.
[0053]
When the optical recording material of the present invention is contained in the recording layer of the optical recording medium, the amount used with respect to the recording layer is preferably 50 to 100% by weight.
[0054]
In addition to the optical recording material of the present invention, the recording layer may contain resins such as polyethylene, polyester, polystyrene, and polycarbonate, if necessary, a surfactant, an antistatic agent, a lubricant, You may contain a flame retardant, a stabilizer, a dispersing agent, antioxidant, a crosslinking agent, etc.
[0055]
Further, the recording layer may contain an aromatic nitroso compound, a transition metal chelate compound, or the like as a quencher such as singlet oxygen. As these compounds, for example, known compounds as proposed in JP-A-59-55795 are used. The compound is preferably used in the range of 0 to 50% by weight based on the recording layer.
[0056]
The material of the base for forming such a recording layer is not particularly limited as long as it is substantially transparent to writing light and reading light. For example, a resin such as polymethyl methacrylate, polyethylene terephthalate, and polycarbonate is used. Glass or the like is used. Moreover, the shape can use arbitrary shapes, such as a tape, a drum, a belt, according to a use.
[0057]
In addition, a reflective film can be formed on the recording layer by vapor deposition or sputtering using gold, silver, aluminum, copper, or a protective layer made of acrylic resin, ultraviolet curable resin, or the like. it can.
[0058]
The optical recording material of the present invention can be used as a dye for optical disks such as LD, CD, DVD, CD-R, and DVD-R, and in particular, DVD-R that uses light having a wavelength of 620 to 690 nm for writing and reproduction. It is suitable for.
[0059]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples.
[0060]
Example 1
A titanium chelate compound (T-50: manufactured by Nippon Soda Co., Ltd.) was applied and hydrolyzed to form a base layer (0.01 μm) on a 12 cm diameter polycarbonate disk substrate. A 1: 0.1 (weight ratio) ethyl cellosolve solution of a nitroso compound (DQ-24: manufactured by Asahi Denka Kogyo Co., Ltd.) was applied by a spin coating method to form a recording layer having a thickness of 100 nm.
[0061]
Further, a 100 nm gold reflective film was formed on the recording layer by vapor deposition.
[0062]
Writing was performed from the back side of the substrate using a semiconductor laser (635 nm, condensing unit output 7 mW, frequency 2 KHz) while rotating each medium thus prepared at 3.6 m / s.
[0063]
Next, a semiconductor laser (650 nm, condensing part output 0.1 mW) was used as the readout light, the reflected light through the substrate was detected, and the C / N ratio was measured with a spectrum analyzer at a bandwidth of 30 KHz.
[0064]
Also, the back surface of the substrate after 0.1 mW laser as reading light, 1 μsec wide, 3 KHz pulse after irradiation for 5 minutes in a static state and after storage for 2500 hours at 40 ° C. and 88% relative humidity The change (%) in reflectance from the side was measured.
[0065]
The results are shown in [Table 1] below.
[0066]
[Table 1]

[0067]
Embedded image

[0068]
Embedded image

[0069]
Example 2
Each medium was prepared in the same manner as in Example 1 using the dyes shown in [Table 2] below, and the refractive index (n) and extinction coefficient were measured using a spectroscopic ellipsometer (M-150, manufactured by JASCO Corporation). (K) was measured. The results are shown in [Table 2] below.
[0070]
[Table 2]

[0071]
As is clear from the above examples, the compounds represented by the general formula (I) according to the present invention (cyanine dyes having a nitro group) were used (Examples 1-1 to 1-9, 2-1). ˜2-9) is superior in writing sensitivity as compared with the case of using a conventional cyanine dye (Comparative Examples 1-1, 1-2, 2-1, 2-2), and after irradiation and after storage. Since the reduction in reflectance is extremely small and the balance between n and k is excellent, extremely reliable recording is possible.
[0072]
【The invention's effect】
The optical recording material of the present invention has good light stability, storage stability and solubility in a solvent, and has high sensitivity.

Claims (4)

An optical recording material comprising a compound represented by the following general formula (I):

(In the formula, A represents a nitro group, B represents an alkyl group having 1 to 8 carbon atoms, a halogen atom, a nitrile group, or a nitro group , and R ₁ and R ₂ each independently represents an alkyl having 1 to 8 carbon atoms. group or a _{group, - (Y-O) q} -R 3 -Z (Y represents an alkylene group having 2 to 4 carbon atoms, R ₃ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, Z represents a a hydrogen atom or a halogen atom), X is -C (CH _{3) 2} -. indicates, an ^- represents an anion, p is 1, q is 1). 2. The optical recording material according to claim 1, wherein in the general formula (I), B is a nitrile group. 2. The optical recording material according to claim 1, wherein, in the general formula (I), B is a nitro group. The optical recording material according to any one of claims 1 to 3 , which is used for an optical recording medium capable of writing and reproducing at a wavelength of 620 to 690 nm.