Metallocenyl-phthalocyanines

Details Metallocenyl-phthalocyanines Metallocenyl-phthalocyanines

1999-08-02

2002-06-04

Shah, Mukund J. (Department: 1624)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C540S139000, C556S143000, C428S064100

Reexamination Certificate

active

06399768

ABSTRACT:

The present invention relates to novel metallocenyl-phthalocyanines, to a process for their preparation and to their use.
The field of this invention is that of the optical recording of information for writable recording media, the information being recorded via different optical properties of a dye on written and unwritten places. Corresponding recording media are known, for example, under the name “WORM” systems (
w
rite
o
nce
r
ead
m
any) and are further categorised into e.g. “CD-R” or “DVD-R”.
The use of dyes which absorb radiation in the near infrared range (NIR range) for recording information in WORM systems is described, inter alia, by M. Emmelius in Angewandte Chemie, No. 11, pages 1475-1502 (1989). By irradiating such recording materials with laser it is possible to achieve the change in absorption required for recording information in binary form via physical changes (for example by sublimation or diffusion) or via chemical changes (for example photochromism, isomerisations or thermal decomposition of the dye).
Substituted phthalocyanines are an important class of dyes for use in such WORM systems because they have high NIR absorptions in the range from 700 nm to 900 nm when correspondingly substituted and dependent on the central atom which is usually present.
The most stringent requirements are placed on the recording layer to be used, such as high refractive index, high initial reflectivity, narrow absorption bands in the solid state, uniformity of the writing width at different pulse duration, high light stability in daylight as well as under weak laser radiation (readout) coupled with high sensitivity to intense laser radiation (inscribing), low noise, high resolution as well as, most importantly, very little statistical jitter of the pits over a desired value at optimum writing performance.
As the recording layer is normally applied from a solution, typically by spin-coating, the dyes should also be readily soluble in conventional solvents, which are described, inter alia, in EP-A 511 598 (independently from the distinction made therein between polar and nonpolar solvent).
Phthalocyanine compounds containing at least one ferrocene unit as substituent are known. J. Organomet. Chem. 468(1-2) (1994), for example, describes 205-212 1, 1″,1″″,1 ″″″(29H,31H-phthalocyanine-2,9,16,23-tetrayl)tetrakis-ferrocene; Quin. Chem. Lett. 4(4) (1993) 339-342 describes [1-(11-ferrocenylundecyl)-1′-[4-[4-[[9,16,23-tris(2,2-dimethylpropoxy)-29H,31H-phthalocyanine-2-yl]oxy]phenoxy]butyl]4,4 ′-bipyridiniumato(2-)-N
29
,N
30
,N
31
,N
32
]-zinc dibromide; New J. Chem. 21(2) (1997) 267-271 describes 1,1″-[[9,23-bis(dodecylthio)29H,31,H-phthalocyanine-2,16-diyl]bis(nitrilomethylidine)]bisferrocene; and J. Organomet. Chem. 541(1-2) (1997) 441-443 describes the synthesis of [Cp(dppe)Fe—CN—MnPc]
2
O (with dppe=1,2-ethanediylbis(diphenylphosphine); Cp=cyclopentadienyl; Pc=phthalocyanine).
J.Chem.Soc., Chem.Commun. 1995,1715-1716 describes the preparation of liquid crystalline ferrocenyl-phthalocyanines, ferrocenecarbonyl chloride being reacted with a hydroxy group-substituted and metal-free phthalocyanine to the corresponding ester compound.
Inorg. Chem. 37 (1998) 411-417 describes the synthesis of bis(ferrocenecarboxylato)(phthalocyaninato)silicium, the ferrocene unit being bound to the central atom.
WO-A 9723354 describes optical recording materials based on phthalocyanines which contain as substituents inter alia ferrocene units bound to the central atom.
The use of CD-R as archiving and back-up media for computer data increasingly requires faster writing speeds. In contrast, use as audio medium requires slower (1x) speeds. Accordingly, the recording layers continuously need to be optimised for such a wide-band behaviour (at present 1x-8x), which places extraordinarily high requirements on the recording layers to be used. It is known that recording layers containing phthalocyanines show very good measurement values for high speeds (2x-6x) but less favourable 1x-values for the length deviation of the pits and lands from the norm, and also for the jitter. Jitter is in effect understood to be a time error at the change of a signal as a result of a pit or a marked range being too short or too long. On a CD-R, for example, the length of the pits can vary between 3T and 11T (1T=231.4 ns). If, for example, the length of a 3T pit is even marginally fallen short of or exceeded, then this may result in an increased number of BLERs (=block error rate, designating the number of physical errors on the CD) and thus in a loss in quality. The error rate (BLER) should as a rule be less than 220 per second.
Different proposals have been made to solve the cited difficulties when using phthalocyanines; in particular attempts were made to lower the decomposition temperature which is higher than that of other dye classes, especially cyanines.
DE-A 4 112 402, for example, proposes to use as recording film a mixture consisting of a phthalocyanine and a cyanine (as light absorber element) which absorbs in the cited wave-length range. However, also in this instance does repeated readout result in the destruction of the light absorber so that the desired properties are not obtained. It is moreover known that cyanine dyes are not lightfast and that it is therefore usually necessary to add a stabiliser.
EP-A 600 427 describes an optical recording medium, the recording layer of which comprises a phthalocyanine and an additive, e.g. a ferrocene derivative, a metal acetylacetonate or an antiknock additive. According to that application, the addition of the cited additives improves the quality of the recording. Disadvantages are, however, the use of an additional substance in the form of an additive and the difficulties in the recovery of the dye which is obtained in the production of the recording layer because, to use the dye again, the additive must either be removed or its amount must be readjusted.
JP-A 8-118800 describes optical recording media, the recording layer of which comprises an azo compound which is substituted by a ferrocene unit. Furthermore, mixtures of these azo compounds with, inter alia, phthalocyanines and pentamethinecyanines are described. The disadvantage in this case is that neither the azo compound nor the phthalocyanines can be used by themselves to give a satisfactory recording layer.
Accordingly, it is the object of this invention to provide additional phthalocyanines which are substituted by metallocene units and to provide improved recording materials based on phthalocyanines for the production of, and for use in, optical recording media. In particular, the metallocenyl-phthalocyanines used as recording materials in optical information recording media, preferably in CD-R, shall fulfill the desired wide-band behaviour (1x-8x) and shall have excellent recording and reproduction characteristics in the wave-length of a semiconductor laser (770-790 nm).
In addition, preferred jitter values in the range of ±35 ns and length deviations in the ranges of ±40 ns (T3 pits/lands) and ±60 ns (T11 pits/lands) shall be maintained.
Furthermore, an improved process for the recovery of the dye used in the production of the recording layer shall be found. It should moreover be possible to use the metallocenyl-phthalocyanines by themselves, i.e. without additional additives, as recording materials.
Accordingly, a metallocenyl-phthalocyanine or its metal complex of a divalent metal, oxometal, halogenometal or hydroxymetal has been found in which at least one of the four phenyl rings of the phthalocyanines contains, bound via a bridge unit E, at least one metallocene radical as substituent, E being composed of a chain of at least two atoms or atom groups selected from the group consisting of —CH
2
—, —C(═O)—, —CH(C
1
-C
4
alkyl)—, —C(C
1
-C
4
alkyl)
2
—, —NH—, —S—, —O— and —CH═CH—.
In addition there have been

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