Soluble copper amino alkoxides

More storage stable solutions comprising an organic solvent containing a soluble copper amino alkoxide are disclosed. The compound is of the formula ##STR1## where and R is lower alkyl such as methyl or ethyl.

BACKGROUND OF THE INVENTION 
Certain disclosures exist in the prior art in regard to copper amino 
alkoxide compositions, for example. For example, Japanese Patent 
Publication No. 62/240,691, dated Oct. 21, 1987, describes compounds of 
the general formula Cu(ORNR'.sub.2).sub.2 where R is alkylene and at least 
one R' is hydroxyalkyl. 
More recently, in Science (Jan. 6, 1989), Vol. 243, pp. 66-69 a 
hydrolyzable compound of the formula Cu(OCH.sub.2 CH.sub.2 N(C.sub.2 
H.sub.5).sub.2).sub.2, for example, is disclosed in regard to the 
formation of the superconductor YBa.sub.2 Cu.sub.3 O.sub.6+x. 
Related U.S. Ser. No. 270,570, filed Nov. 18, 1988, of Carl C. Greco et al. 
discloses certain metal (dialkylaminoalcoholate) solutions of the general 
formula M(ORNR'.sub.2).sub.2, where M is a superconductor metal precursor 
(e.g., copper), R is alkylene of from 2 to 3 carbon atoms, and R' is alkyl 
of from 1 to 8 carbon atoms. Examples of suitable compounds which are 
given in this related application have the general formula Cu(OCH.sub.2 
CH.sub.2 NR'.sub.2).sub.2 where R' can be methyl or ethyl. Solutions 
containing such copper compounds, for example, dissolved therein can be 
formed but, upon standing for several weeks or more, some degree of 
undesired precipitation of the copper (dialkylaminoalcoholate) values 
originally dissolved therein. 
U.S. Pat. No. 3,856,835 to D. G. Guillot describes various reaction 
products of an organometallic compound and an aminopolyol which are useful 
as catalyst compositions for the polymerization of an epoxide compound. 
Examples 11-12 describe the polymerization of propylene oxide in the 
presence of a catalyst formed by the reaction of diphenylmagnesium with a 
lower molar amount of either 3-dimethylamino-l,2-propanediol or 
3-diethylamino-l,2-propanediol This patent fails to describe the structure 
of its catalyst composition other than indicating that some 
carbon-magnesium bonds remain unreacted. All of the Examples use a 
magnesium-containing organometallic reactant and do not employ any with 
such metals as zinc, aluminum, calcium, cadmium, strontium, gallium, or 
barium The compositions formed using the process described in the Guillot 
patent would be mixtures and not substantially pure heavy metal amino 
alkoxides as described herein. 
SUMMARY OF THE INVENTION 
Superior solutions having greater storage stability (i.e. a lessened 
tendency for precipitation of the metal compounds contained dissolved 
therein) can be formed in accordance with the present invention. The 
present invention relates to compounds of the general formula 
##STR2## 
where M is a heavy metal (such as barium, lead, copper, or the like) and R 
is lower alkyl and to solutions containing them. 
DETAILED DESCRIPTION OF THE INVENTION 
The compounds of the present invention relate to heavy metal amino alkoxide 
compounds of the formula just given above where R can be lower alkyl of 
from about 1 to about 3 carbon atoms. Representative examples include 
those compounds where R is methyl or ethyl. The term "heavy metal" as used 
herein is deemed to be inclusive of those heavy metals having an atomic 
weight of about 60 or greater capable of forming the type of compounds 
depicted therein and are inclusive of such alkaline earth metals as barium 
and strontium and such transition metals as copper and lead. The metals 
are divalent and, when combined with the amino alkoxide ligands shown, are 
believed to be capable of six coordination sites The first two are 
believed to be covalent bonds with the oxygen atoms leading to the alkyl 
amino groups. The next two are believed to be coordination bonds between 
the electron rich hydroxy substituents. The last two are believed to be 
coordination bonds between the two electron rich nitrogen atoms of the 
amino functionality. However, this coordination explanation for the good 
solubility should be construed as no more than a possible theoretical 
explanation for the present invention by which the present applicant does 
not intend to be bound. 
These compounds can be easily synthesized as described in greater detail in 
Examples 2 and 3 shown below by suspending the metal alkoxide, such as 
copper methoxide, in an appropriate organic solvent, such as 
tetrahydrofuran, followed by the addition of 
3-(dialkylamino)-l,2-propanediol with appropriate heating of the mixture 
to bring about the appropriate exchange reaction and yield the solution 
containing the desired copper amino alkoxide therein. As demonstrated by a 
comparison of Example 4 and Comparative Example 5, below, the instant 
compounds have superior solubility over time as compared to the type of 
copper (dialkylaminoalcoholate) compounds covered in U.S. Ser. No. 
270,570. Examples 6 and 7 illustrate synthesis of lead and barium amino 
alkoxides pursuant to this invention. The solutions have utility, for 
example, in forming superconductor precursor compositions which can be 
calcined to form a superconductor oxide composition. 
The present invention, unlike the Guillot disclosure, allows for the 
production of the disclosed heavy metal amino alkoxides in substantially 
pure form substantially free of metal-carbon bonds since they are not 
synthesized using organometallic compounds as a reagent. The term 
"substantially pure" as used herein is intended to connote compositions of 
such heavy metal amino alkoxides which are free from the metal-carbon 
component which must be present in the Guillot compositions. 
The present invention is further illustrated by the Examples which follow.

EXAMPLE 1 
Copper (II) chloride (34 gm, 0.25 mole) was dissolved in 600 cc of methanol 
and 5 gm (0.725 mole) of lithium was then added. The solution was stirred 
for four hours at room temperature at the end of which a blue solid 
precipitate had formed. The precipitate was filtered from the reaction 
mixture and was washed four times with 250 cc of methanol each time The 
blue solid (copper methoxide) was vacuum dried and was used in Examples 2 
and 3. 
EXAMPLE 2 
Copper methoxide (15 gm, 0.12 mole) from Example 1 was suspended in 350 cc 
of tetrahydrofuran at room temperature. To this was added, with good 
stirring, over a fifteen minute period, 35 gm of 
3-(diethylamino)-l,2-propanediol (0.24 mole). The resulting solution was 
refluxed for one hour during which time 50 cc of solvent was removed. The 
solution was then collected as the product. Analysis showed 3.11% copper 
in solution. Therefore, according to the analysis, the amount of copper 
alkoxide of the formula 
##STR3## 
in solution was 17.4 gm or 9.2%, by weight. 
EXAMPLE 3 
Copper methoxide (10.5 gm, 0.084 mole) from Example 1 was suspended in 350 
cc of toluene at room temperature. To this was added 24.6 gm of 
3-(diethylamino)-l,2-propanediol (0.168 mole). The resulting solution was 
refluxed for two hours and was then stripped of solvent. Distillation was 
performed under slight vacuum using a pot temperature of around 80.degree. 
C. A viscous oil remained as the product (29.8 gm). This oil was analyzed 
and was then redissolved in 211 gm of toluene to arrive at a concentration 
of the desired copper alkoxide, as in Example 2, of 12%, by weight The 
solution was stored in a dry box for about three months with no evidence 
of any precipitation. 
EXAMPLE 4 
In a 500 ml, one neck flask, was added 150 gm of the copper 
alkoxide-tetrahydrofuran solution from Example 2. This solution contained 
3.11%, by weight, of copper (0.0735 mole). To this solution was added 190 
gm of the barium alkoxide of diethylaminopropanediol in xylene solution. 
This solution contained 3.5%, by weight, barium (0.049 mole). Finally, 
there was added 59 gm of a solution of yttrium diethylaminoethoxide in 
xylene containing 3.7%, by weight, yttrium (0.0245 mole). The above 
solution was distilled at 80.degree. C. under a vacuum of 80 mm of mercury 
to a final residue weight of 155 gm. The solutions therefore contained 
3.02%, by weight, copper, 4.35%, by weight, barium, and 1.41%, by weight, 
yttrium. This solution was extremely storage stable with no signs of 
precipitation after standing two months. 
COMATIVE EXAMPLE 5 
In 600 cc of methanol was dissolved 34 gm of copper (II) chloride (0.253 
mole) To this solution was added 5 gm of lithium (0.725 mole) The solution 
was stirred for four hours at room temperature At the end of this time 
there was formation of a blue solid precipitate (copper methoxide) The 
precipitate was filtered from the reaction mixture and was washed four 
times With 250 cc of methanol each time to remove LiCl and unreacted 
copper chloride. The blue solid was vacuum dried in the vacuum oven at 
40.degree. C. under nitrogen, and was then suspended in 400 cc of toluene. 
To this slurry was added 86 gm (0.76 mole) of diethylaminoethanol over a 
ten minute period. The reaction mixture was heated to 35.degree. C. under 
a vacuum of 25 mm of mercury for forty-five minutes to remove the 
methanol. About 100 cc of methanol-toluene was distilled off during this 
time, keeping the pot temperature below 40.degree. C. A clear dark blue 
solution resulted after the heating period and was diluted with more 
toluene to arrive at a final weight of 668 gm. The amount of copper 
alkoxide, of the formula Cu(OCH.sub.2 CH.sub.2 N(Et).sub.2).sub.2, in this 
solution was 74.8 gm or 11.2%, by weight. 
The material was stored in a dry box for several weeks with no evidence of 
any precipitation A portion of this material was mixed with a solution of 
barium diethylaminoethoxide and allowed to stand at room temperature under 
nitrogen. This solution was also stable for many weeks. No sign of 
precipitation was noted. However, after one month's standing there was a 
slight formation of a precipitate in the original copper alkoxide 
solution. The amount of precipitation can be increased by heating the 
solution above 50.degree. C. for only a few hours. 
EXAMPLE 6 
A one liter, three neck flask was equipped with a condenser thermometer, 
stirrer, and addition funnel Lead (II) acetylacetonate (40.5 gm) and 600 
cc of xylene was added to the flask. To this slurry was then added 29.4 gm 
(0.2 mole) of 3-(diethylamino)l,2-propanediol under a blanket of nitrogen. 
The reaction was heated to reflux at which point all solids became soluble 
The reaction mixture was refluxed for two hours during which time 150 cc 
of solvent was distilled off. The distillation was required to remove 
by-product acetylacetone. The reaction mixture was filtered to remove a 
small amount of fines. The filtrate weight 328 gm and contained 6.3% lead. 
The yield was quantitative for lead diethylamino-hydroxypropoxide of the 
following formula: 
##STR4## 
This lead compound can be spun coated onto an appropriate substrate and 
pyrolyzed to form a lead oxide coating. 
EXAMPLE 7 
To the same equipment used in Example 6 was added 16.4 gm (0.12 mole) of 
barium metal and 250 cc of xylene To the resulting slurry was added 35 gm 
(0.24 mole) of 3-(diethylamino)l,2-propanediol under a blanket of 
nitrogen. The reaction was heated to reflux and all solids solubilized as 
hydrogen was observed coming off from the reaction media. The reaction 
media was refluxed for two hours during which time most of the hydrogen 
was evolved. The reaction mixture was then filtered to remove a small 
amount of fines. The filtrate weighed 396 gm and contained 3.54% barium. 
The yield (83.3%) of the theoretical amount of the desired barium compound 
of the formula: 
##STR5## 
The amino alkoxides shown herein can be applied in organic coatings to an 
appropriate substrate and be pyrolyzed to form metal oxide films. 
The foregoing Examples are provided to illustrate certain embodiments of 
the invention and should, for that reason, not be construed in a limiting 
sense. The scope of protection that is desired is set forth in the claims 
which follow.