Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Utility Patent
2000-01-25
2001-01-02
Shaver, Paul F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C556S009000, C556S087000, C556S095000
Utility Patent
active
06169193
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to derivatives of siloles and germoles which have desirable electronic properties. More particularly, it relates to polysiloles, polygermoles, and silole-germole copolymers.
Siloles are compounds having a 5-member ring in which there are four carbons in the ring and one silicon. There are also two double bonds not involving the silicon. The ring may be substituted (or not) insofar as the carbon atoms are concerned, and the silicon is linked to two adjacent ring carbons. Typically, the silicon is also linked to two other atoms outside the ring (e.g. halogens). Germoles are similar except that germanium substitutes for silicon in the ring.
Siloles and germoles are of considerable commercial interest because of their unusual electronic properties. In particular, it has been proposed that they be used for electro-transporting materials and light-emitting diodes.
Recently, silole-polysilane copolymers were reported where single silole units were linked to a standard polysilane moiety, that moiety in turn being the repeat unit of the polymer. See generally T. Sanji et al., 120 J. Am. Chem. Soc. 4552-4553 (1998). The disclosure of this publication and of all other publications referred to herein are incorporated by reference as if fully set forth herein.
Also, there was a recent report of the synthesis of a four repeat silole oligomer. See Yamaguchi et al., 16 Organometalics 2486-2488 (1997). However, such oligomers do not have desirable film forming properties, or certain desired electrical properties. This greatly limits their utility.
There is therefore a continuing desire to develop additional compounds having varied electrical properties, particularly with respect to fluorescence, electroluminescence, and semiconducting.
BRIEF SUMMARY OF THE INVENTION
In one aspect, the invention provides compounds containing the following moiety:
wherein M is selected from the group consisting of silicon and germanium; n is at least five (preferably less than 10,000, even more preferably less than 500, most preferably between 8 and 100); and R
1
, R
2
, R
3
, and R
4
are for each of the n's individually selected from the group consisting of hydrogen, fluorine, alkyl having less than 30 carbons, alkoxy having less than 30 carbons, alkyl silyl having less than 30 carbons, arylalkyl having less than 30 carbons, and aryl having less than 30 carbons.
Most preferably, all R
1
, R
2
, R
3
, and R
4
are aryl, such as substituted or unsubstituted phenyl. For some applications, it is preferred that the compound be a homopolymer of such moieties, or a compound whose molecular weight is at least 90% from such moieties. In using the term homopolymer it should be understood that the term is meant to include polymers in which the units are identical except that in the terminal units the Si (or Ge) will be linked to some form of terminal group or atom (e.g. halogen, o-alkyl).
In one form, M is silicon for all n's. In another, M is germanium for all n's. In still another, M is silicon for at least one n and germanium for at least one n (e.g. they alternate).
In another aspect the invention provides a method of making the above compounds. One reacts dianions of one or more compounds selected from the group consisting of siloles and germoles, and/or salts thereof, with one or more compositions selected from the group consisting of dihalogenated siloles and dihalogenated germoles (in each case the dihalogenation referring to substitution on silicon or germanium). The overall conditions of the reaction are effective to cause a polymerization reaction (heat over 50° C., preferably over 125° C.).
In yet another aspect, the invention provides an alternative method of making the above compounds. One reduces a plurality of units of one or more chemicals selected from the group consisting of dihalogenated siloles and dihalogenated germoles (in each case the dihalogenation referring to substitution on silicon or germanium) using a material selected from the group consisting of lithium metal, sodium metal, and potassium metal. The reduced units are then coupled at a reaction condition above 50° C., preferably above 125° C.
Compounds made by the above methods have been determined to have important electrical properties. They are fluorescent and have shown electroluminescent properties. They should be particularly useful in organic transistors, in contexts where electron transporting materials are desired, and for single compound LED's for flat panel displays.
The objects of the present invention therefore include providing:
(a) compounds of the above kind which are fluorescent;
(b) compounds of the above kind which are electroluminescent; and
(c) efficient methods of making such compounds.
These and still other objects and advantages of the present invention (e.g. room temperature stability) will be apparent from the description which follows. The following description is merely of the preferred embodiments. The claims should therefore be looked to in order to understand the full scope of the invention.
REFERENCES:
patent: 5412105 (1995-05-01), Ito et al.
patent: 5498736 (1996-03-01), Tamao et al.
patent: 5741921 (1998-04-01), Kreuder et al.
T. Sanji et al., Silole-Incorporated Polysilanes, 120 J.Am. Chem. Soc. 4552-4553 (1998).
Yamguchi et al., Silicon-Catenated Silole Oligomers: Oligo(1,1-silole)s, 16 Organometallics 2486-2488 (1997).
W. Joo et al., Synthesis and reactivity of 1,1-disodio-2,3,4,5-tetraphenyl-1-silacyclopentadiene, 391 J. Organomet. Chem. 27-36 (1990).
R. West et al., The Dianion of Tetraphenylgermole is Aromatic, 36 Angewandte Chemie Int. Ed. Engl. 1002-1004 (1996).
Liu Yuxia
Sohn Honglae
West Robert C.
Quarles & Brady
Shaver Paul F.
Wisconsin Alumni Research Foundation
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