Modifying POSS compounds

Details Modifying POSS compounds Modifying POSS compounds

2000-11-14

2003-12-09

Moore, Margaret G. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

C528S009000, C556S010000, C556S403000, C556S408000, C556S409000, C556S452000, C556S459000, C556S460000

Reexamination Certificate

active

06660823

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to modifying polyhedral oligomeric silsesquioxane (POSS) compounds, particularly methods for controlling the stereo chemistry of functionalities or X groups to desired positions on POSS compounds and also to methods for inserting one or more ring substituents, other than silicon, into a POSS compound.
2. Description of Related Art
Recent art in the silsesquioxane field has taught processes for the chemical manipulation of the organic functionalities (substituents, e.g., denoted by R) contained on the silicon oxygen frameworks of polyhedral oligomeric silsesquioxanes (POSS). While these methods are highly useful for varying the organic functionalities contained on POSS molecules, they do not offer the ability to cleave and/or manipulate the silicon-oxygen frameworks of such compounds. Thus, these methods are of no utility for transforming the multitude of readily available polyhedral oligomeric silsesquioxanes systems into useful compounds that can be subsequently utilized for a multitude of catalysis and material applications.
Earlier art has reported that bases (e.g. NaOH, KOH, etc.) could be used to (1) catalyze the polymerization of polyhedral oligomeric silsesquioxanes into partly networked resins, (2) convert polysilsesquioxane resins into discrete polyhedral oligomeric silsesquioxane structures and (3) catalyze the redistribution of selected fully condensed polyhedral oligomeric silsesquioxane structures into other related fully condensed polyhedral oligomeric silsesquioxane structural types. While the base assisted/catalyzed method does afford the manipulation of silicon-oxygen frameworks, it is not effective at selectively producing incompletely condensed frameworks from completely condensed species. This limitation results from the intolerance of the silicon-oxygen framework present in polyhedral oligomeric silsesquioxanes to base.
Accordingly there is need and market for a method for opening and/or substituting on POSS rings that overcomes the above prior art shortcomings.
There has now been discovered a method that rapidly and effectively opens the silicon-oxygen frameworks of POSS compounds to produce species that can subsequently be converted to various functionalized POSS compounds.
SUMMARY OF THE INVENTION
Broadly the present invention provides a method for controlling the stereo chemistry of X groups to exo or endo positions on a polyhedral oligomeric silsesquioxane (POSS) compound including, adding reagents selected from the group of a) CF
3
SO
3
H then H
2
O, b) Me
3
SnOH then HCl aq. and c) HBF
4
/BF
3
then Me
3
SnOH then HCl aq, to the X groups to change one or more positions thereof to endo or exo, wherein the POSS compound is of the formula [(RSiO
1.5
)
m
(RXSiO
1.0
)
n
]
&Sgr;#
, n=4-24, m=1-12, #=m+n, R is aliphatic, aromatic, olefinic, alkoxy, siloxy or H and the X groups are selected from the type of OH, OSO
2
CF
3
, OSO
2
CH
3
, F, Cl, I, Br, Me
3
SnO, alkoxy and siloxy. Also provided are the POSS species formed by the above inventive method.
The invention further provides a method for inserting a ring substituent into a polyhedral oligomeric silsesquioxane (POSS) compound to produce a formula of the type [(RSiO 1.5)
m
(RSiO
1.0
)
n
(E)
j
]
&Sgr;#
. This includes, reacting [(RSiO
1.5
)
m
(RXSiO
1.0
)
n
]
&Sgr;#
, with a reagent selected from the group of H
2
NR, RB(OH)
2
, K
2
CrO
4
, R
4
NHSO
4
and H
2
PR to obtain at least one expanded POSS ring in [(RSiO
1.5
)
m
(RSiO
1.0
)
n
(E)
j
]
&Sgr;#
, where n is 4-24, m is 1-12, j is 1-8, # is m+n+j, R is aliphatic, aromatic, olefinic, alkoxy, siloxy or H, X is selected from the group of OSO
2
CF
3
, OSNMe
3
, OH, OSO
2
Cl, OSO
2
CH
3
, OS
3
H and halide and E is a ring substituent replacement for oxygen selected from the group of NR, PR, CrO
4
, SO
4
, O
2
BR, O
2
PR and O
2
P(O)R. Also provided are the POSS species formed by such inventive method.
Definition of Molecular Representations for POSS Nanostructures
For the purposes of explaining this invention's processes and chemical compositions the following definition for representations of nanostructural-cage formulas is made:
Polysilsesquioxanes are materials represented by the formula [RSiO
1.5
]
∞
where ∞=degree of polymerization within the material and R=organic substituent (H, cyclic or linear aliphatic or aromatic groups that may additionally contain reactive functionalities such as alcohols, esters, amines, ketones, olefins, ethers or halides). Polysilsesquioxanes may be either homoleptic or heteroleptic. Homoleptic systems contain only one type of R group while heteroleptic systems contain more than one type of R group.
POSS nanostructure compositions are represented by the formula:
[(RSiO
1.5
)
n
]
&Sgr;#
for homoleptic compositions
[(RSiO
1.5
)
m
(RSiO
1.5
)
n
]
&Sgr;#
for heteroleptic compositions
[(RSiO
1.5
)
m
(RXSiO
1.0
)
n
]
&Sgr;#
for functionalized heteroleptic compositions
[(RSiO
1.5
)
m
(RSiO
1.0
)
n
(E)
j
]
&Sgr;#
for heterofunctionalized heteroleptic compositions
[(XSiO
1.5
)]
&Sgr;#
for homoleptic silicate compositions
In all of the above R is the same as defined above and X includes OH, Cl, Br, I, alkoxide (OR), acetate (OOCR), peroxide (OOR), amine (NR
2
) isocyanate (NCO), and R. The symbol E refers to elements within the composition that include (silanes and silicones e.g. SiR
2
, SiR
2
OSiR
2
OSiR
2
), (metals and nonmetals e.g. CrO
2
, PO
2
, SO
2
, NR) The symbols m, n and j refer to the stoichiometry of the composition. The symbol &Sgr; indicates that the composition forms a nanostructure and the symbol # refers to the number of silicon atoms contained within the nanostructure. The value for # is usually the sum of m+n or m+n+j. It should be noted that &Sgr;# is not to be confused as a multiplier for determining stoichiometry, as it merely describes the overall nanostructural characteristics of the POSS system (aka cage size).
By “strong acid”, as used herein, is meant one with a pKa number ranging from −7 to 5 and is inclusive of superacids which cannot be assigned pKa values but which are characterized by Hammett acidity values H
0
that range from 30 to 2.0 with the preferred range being 8-16.
Thus the present invention discloses methods that enable the selective manipulation of the silicon-oxygen frameworks in polyhedral oligomeric silsesquioxane (POSS) cage molecules. It is desired to selectively manipulate the frameworks of POSS compounds because they are useful as intermediate chemical agents that can be further converted or incorporated into a wide variety of chemical feed-stocks useful for the preparation of catalyst supports, monomers, and polymers wherein they impart new and improved thermal, mechanical and physical properties to common polymeric materials.
Further the present invention teaches processes that enable the manipulation of the silicon-oxygen frameworks (the cage-like structure) of common polyhedral oligomeric silsesquioxane (POSS) compounds [(RSiO
1.5
)
n
]
&Sgr;#
(where R=aliphatic, aromatic, olefinic, alkoxy, siloxy or H and n=4-24) into new POSS species bearing frameworks with functionalities (e.g. silanes, silylhalides, silanols, silylamines, organohalides, alcohols, alkoxides, amines, cyanates, nitriles, olefins, epoxides, organoacids, esters, and strained olefins) for grafting, polymerization, or catalysis reactions.
Also in contrast to the prior art, the invention provides for the development of acid catalyzed processes that rapidly and effectively open the silicon-oxygen frameworks of polyhedral oligomeric silsesquioxanes to produce species that can subsequently be converted into stable incompletely condensed POSS-silanol and related functionalized POSS compounds. The use of acid reagents is desirable because the silicon-oxygen frameworks i

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