Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-06-22
2002-12-24
Raymond, Richard L. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06498249
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to new compounds that are a combination of covalently linked phthalocyanine and linear siloxane polymeric structures having a unique and novel combination of optical and rheological properties which are useful in protective eye wear, nonlinear optical devices and for optical data storage applications.
2. Description of the Related Art
Previously developed phthalocyanine materials have not possessed the handling and processing characteristics of a single-component fluid coupled with an optical transparency, nonlinear optical absorption and refraction, chemical stability and moisture resistance. These are desirable characteristics for use as thin films in nonlinear optical and optical recording applications. Known methods for preparing phthalocyanines as thin films include vacuum deposition (sublimation, molecular beam, laser desorption), spraying or casting of a fine suspension or solution, Langmuir-Blodgett transfer, mechanical abrasion, and dispersion in a binder. The transparent thin film is a highly desirable physical form for these materials as it allows utilization of the chromophore in optical applications such as optical limiting and optical recording media which typically involve as material response to irradiation with a laser.
The deposition method, optical quality, and stability of a phthalocyanine film are determined by the molecular structure and properties of the material. Without peripheral substituents, phthalocyanine compounds are microcrystalline and relatively insoluble. Thin film preparation by vacuum deposition or high pressure abrasive techniques must frequently be accompanied by high temperatures. The microcrystalline character and the presence of different crystalline polymorphs contribute to optical scattering. These effects diminish the transparency of the phthalocyanine film. Temperature variation and exposure to chemical vapors (including water) causes conversions between different crystalline forms further diminishing the quality of the film. (See M. S. Mindorff and D. E. Brodie,
Can. J. Phys.,
59, 249 (1981); F. Iwatsu, T. Kobayashi and N. Uyeda,
J. Phys. Chem.,
84, 3223 (1980); F. W. Karasek and J. C. Decius,
J. Am. Chem. Soc.,
74, 4716 (1952))
When peripheral substituents are bonded to the phthalocyanine, molecular packing efficiency and crystallinity are reduced, and the resultant materials may be soluble in a variety of solvents. Film forming techniques involving the use of solvents, such as simple evaporation methods and Langmuir-Blodgett transfer techniques, are feasible processing methods. However, many peripherally substituted phthalocyanines do not form films of good transparent optical quality. The peripheral groups need to be large in size and preferably of mixed isomer substitution to be effective. While crystalline packing is hindered by the presence of peripheral substituents, there are strong attractive van der Waal forces at work between the planar faces of phthalocyanine rings which result in the constituent molecules aggregating into ordered domains. These domains, if large enough, cause optical scattering which strongly deteriorates the transparency and optical quality of thin films. (See T. Kobayashi, in
Crystals: Growth Properties and Applications
, N. Karl, editor, Springer-Verlag, New York, Vol 13 (1991) pp. 1-63; A. Yamashita and T. Hayashi,
Adv. Mater.,
8, 791 (1996)).
The interaction between adjacent phthalocyanine rings in an aggregate also results in a strong electronic perturbation of the molecular structure and a broadening of its absorption in the visible spectrum. This interaction in many cases detracts from the sought after nonlinear optical properties. (See S. R. Flom, J. S. Shirk, J. R. Lindle, F. J. Bartoli, Z. H. Kafafi, R. G. S. Pong and A. W. Snow, in
Materials Res. Soc. Proc.,
Vol. 247, (1992) pp 271-276).
Control of phthalocyanine aggregation is important first to reduce the ordered domain size below a threshold where optical scattering occurs and second to reduce the pertubation of the phthalocyanine electronic structure to a level where spectral broadening and excited state lifetime shortening do not seriously diminish the nonlinear optical absorption of the phthalocyanine chromophore. The former is critical since optical transparency is required for a device of the current invention to function. For sufficient control of optical scattering, the ordered molecular domain size must be smaller than the light wavelength of application interest (usually in the 350 to 1500 nm range). The latter is less critical, but significant improvement in nonlinear optical properties can be realized if aggregation can be reduced to dimer formation or less.
Aggregation can be totally eliminated by blocking the co-facial approach of phthalocyanine rings by axial substitution onto metal ions complexed in the phthalocyanine cavity. (See N. B. McKeown,
J. Mater. Chem.,
10, 1979 (2000); M. Brewis, G. J. Clarkson, V. Goddard, M. Helliwell, A. M. Holder and N. B. McKeown,
Angew. Chem. Int. Ed.,
37, 1092 (1998); A. R. Kane, J. F. Sullivan, D. H. Kenny and M. E. Kenney,
Inorg. Chem.,
9, 1445 (1970)). However, this approach is limited to a small number of tetravalent octahedrally coordinating metals such as silicon. For reasons discussed below, the nonlinear optical properties of this small group of metallophthalocyanines are not particularly useful. (See H. S. Nalwa and J. S. Shirk, in
Phthalocyanines: Properties and Applications
, C. C. Leznoff and A. B. P. Lever, editors, VCH Publishers, Inc., New York (1996) Ch. 3).
Another approach to aggregation control is to utilize very large peripheral substituent groups that hinder the co-facial approach of phthalocyanine rings. Classes of such peripheral substituents are flexible oligomers (see D. Guillon, P. Weber, A. Skoulios, C. Piechocki and J. Simon,
Molec. Cryst. Liq. Cryst.,
130, 223 (1985); P. G. Schouten, J. M. Warman, M. P. Dehaas, C. F. van Nostrum, G. H. Gelineck, R. J. M. Nolte, M. J. Copvyn, J. W. Zwikker, M. K. Engel, M. Hannack, Y. H. Chang and W. T. Ford,
J. Am. Chem. Soc.,
116, 6880 (1994)), dendrimers (see M. Kimura, K. Nakada, Y.,
Chem. Comm.,
1997, 1215; M. Brewis, B. M. Hassan, H. Li, S. Makhseed, N. B. McKeown and N. Thompson,
J. Porphyrins Phthalocyanines,
4, 460 (2000); M. Brewis, M. Helliwell, N. B. McKeown, S. Reynolds and A Shawcross,
Tetrahedron Lett.,
42, 813 (2000)), and capping groups (see D. D. Dominguez, A. W. Snow, J. S. Shirk and R. G. S. Pong,
J. Porphyrins and Phthalocyanines,
5, 582 (2001)). Examples of these three types of peripheral groups have had limited success in reducing aggregation. In many cases where the large peripheral groups have significant structural symmetry and uniformity of size, liquid crystal formation with its consequent optical scattering has resulted. (See N. B. McKeown,
Phthalocyanine Materials: Synthesis, Structure and Function,
Cambridge University Press, Edinburgh (1998) pp. 62-86). The liquid crystallinity has been avoided by utilizing peripheral groups with irregular symmetry combined with hydrogen bonding functional groups (see R. D. George and A. W. Snow,
Chem. Mater.,
6, 1587 (1994)) or using a polydispersity of peripheral group chain lengths (see A. W. Snow, J. S. Shirk and R. G. S. Pong,
J. Porphyrins Phthalocyanines,
4, 518 (2000)). In the former case an epoxy-amine chemistry was utilized and a non-birefringent organic glass was obtained, while in the latter case polyethylene oxide chemistry was employed and an isotropic liquid was obtained. The organic glass or liquid has very favorable melt processing characteristics.
Another requirement on the nature of the peripheral group is that it must be chemically inert toward the metal ions complexed in the phthalocyanine cavity. Many of the metal ions that instill very useful nonlinear optical properties to the phthalocyanine chromophore are moderately labile and may be removed from the phthalocyanine cavity by competing complexing agents. This is particular
Flom Steven R.
Maya Eva M.
Pong Richard G. S.
Shirk James S.
Snow Arthur W.
Forman Rebecca L.
Karasek John J.
Raymond Richard L.
The United States of America as represented by the Secretary of
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