US5059701A
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Methods for preparation of cyclopentadienyliron (II) arenes
Assignee: 3M Co
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Filing: 1990-09-20
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Granted: 1991-10-22
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Expires: 2010-09-20
Abstract
Abstract Two improved methods for preparation of compounds with the structure shown in equation X [(Cp)--Fe--(Ar)].sup.+.sub.b X.sup.b- (X) where Cp is an eta 5 complexed, substituted or unsubstituted, cyclopentadienyl or indenyl anion, Ar is an eta 6 complexed substituted or unsubstituted, pi-arene ligand anad X is a b-valent anion where b is an integer between 1 and 3. The two methods, which differ in the source of the cyclopentadienyl anion - Lewis acid complex, utilize a Lewis acid assisted ligand transfer reaction. The cyclopentadienyl anion ligand, assisted by a Lewis acid is transferred to ferrous ion in the presence of an arene. In the first method, the cyclopentadienyl anion is derived from ferrocene and ferrous chloride. In this reaction, the cyclopentadienyliron (II) arene product is derived partially from ferrocene and partially from the ferrous salt. In the second method, the cyclopentadienyl anion - Lewis acid complex is formed by direct reaction of the Lewis acid with an inorganic cyclopentadienide salt. The cyclopentadienyliron (II) arene product of this reaction is derived entirely from the ferrous salt. Cyclopentadienyliron (II) arene cations are of great interest due to their utility as photoactivatable catalysts for a variety of polymerization reactions.
Inventors
- 👤 Steven J. Keipert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:26
CPC Classifications
C; C07; C07F; C07F15/00; C07F15/02; C07F17/00; C07F17/02
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
44 words
A method for preparing a cyclopentadienyliron (II) arene cation complex salt comprising the steps: a) providing a mixture comprising ferrocene, an arene, a Lewis acid, and a ferrous salt in an amount sufficient to effect complete reaction, b) isolating the product of said reaction.
Claim 2
Independent Claim
44 words
A method for preparing a cyclopentadienyliron (II) arene cation complex salt comprising the steps: a) providing a mixture comprising ferrocene, an arene, a Lewis acid, and a ferrous salt in an amount sufficient to effect complete reaction, b) isolating the product of said reaction.
Claim 3
Dependent Claim
16 words
The method as recited in claim 1 wherein said mixture further comprises an inert, non-polar diluent.
Claim 4
Dependent Claim
25 words
The method as recited in claim 2 wherein said mixture further comprises a reducing metal selected from the group consisting of aluminum, magnesium, and zinc.
Claim 5
Dependent Claim
58 words
The method as recited in claim 3 wherein said cyclopentadienyliron (II) cation complex salt has the formula: ((Cp)--Fe--(Ar)).sup.+.sub.b X.sup.b- wherein Cp is an eta 5 complexed cyclopentadienyl anion, or an eta 5 complexed indenyl anion, Ar is an eta 6 complexed arene, X is an anion of valence b, and b is an integer 1, 2, or 3.
Claim 6
Dependent Claim
75 words
The method of claim 4 wherein said Lewis acid is selected from a first group consisting of aluminum chloride, aluminum bromide, boron chloride, gallium chloride and a combination of a Lewis acid selected from said first group and a Lewis acid selected from a second group consisting of titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride and tin tetrachloride wherein said second Lewis acid, when present, does not exceed a 0.2:1 ratio between said acid and ferrocene.
Claim 7
Dependent Claim
35 words
A method of claim 1 for preparing cyclopentadienyliron (II) arene cation complex salt further comprising: a) quenching the reaction of said reacting step by hydration of said Lewis acid prior to isolating the resulting product.
Claim 8
Dependent Claim
38 words
The method cf claim 6 wherein said quenching step further includes: a) adding absolute alcohol, wherein said absolute alcohol is methanol, ethanol or isopropanol; b) providing external cooling; and c) transferring said reaction mixture to an aqueous mixture.
Claim 9
Dependent Claim
50 words
The method of claim 7 wherein said mixture comprises at least 1 mole of ferrocene, at least 2 moles of arene, at least 0.2 moles of ferrous salt, at least 1 mole of a Lewis acid, at least 0.1 mole of a reducing metal and optionally, an inert, non-polar diluent.
Claim 10
Dependent Claim
54 words
The method of claim 7 wherein said mixture comprises of at least 0.25 mole of ferrocene, 200-300 ml of arene, wherein said arene is one of xylene or cumene, at least 0.75 mole of anhydrous aluminum chloride, at least 0.25 mole of anhydrous ferrous chloride and at least 0.25 g. atom of powdered aluminum.
Claim 11
Dependent Claim
79 words
The method of claim 9 for providing cyclopentadienyliron (II) arene cation complex salt further comprising the step: a) adding PF 6 - or SbF 6 - to said resulting product prior to said isolating step wherein one of cyclopentadienyliron (II) xylene + PF 6 - , cyclopentadienyliron (II) cumene +PF 6 - , cyclopentadienyliron (II) xylene + SbF 6 - or cyclopentadienyliron (II) cumene + SbF 6 - is the product salt precipitated; and b) purifying said precipitated product.
Claim 12
Dependent Claim
25 words
The method of claim 7 wherein said ratio of ferrocene to anhydrous aluminum chloride to anhydrous ferrous chloride to powdered aluminum is at least 1:3:1:1.
Claim 13
Independent Claim
47 words
A method for preparing a cyclopentadienyliron (II) cation complex salt comprising the steps: a) reacting a mixture comprising a metal cyclopentadienide salt, an arene in the presence of a Lewis acid, and with sufficient ferrous salt to effect completion of the reaction; b) isolating the resultant product.
Claim 14
Independent Claim
47 words
A method for preparing a cyclopentadienyliron (II) cation complex salt comprising the steps: a) reacting a mixture comprising a metal cyclopentadienide salt, an arene in the presence of a Lewis acid, and with sufficient ferrous salt to effect completion of the reaction; b) isolating the resultant product.
Claim 15
Dependent Claim
18 words
The method of claim 12 wherein said reaction of said reacting step takes place under an inert atmosphere.
Claim 16
Dependent Claim
15 words
The method of claim 13 wherein said reaction mixture further comprises an inert, non-polar diluent.
Claim 17
Dependent Claim
24 words
The method of claim 14 wherein said reaction mixture further comprises a reducing metal selected from the group consisting of aluminum, magnesium, and zinc.
Claim 18
Dependent Claim
42 words
The method of claim 15 wherein said cyclopentadienide salt has the general formula: M.sup.b+ (Cp).sub.b.sup.- wherein M is a metal cation of valence b, b is an integer 1, 2, or 3, and Cp is a cyclopentadienyl anion, or an indenyl anion.
Claim 19
Dependent Claim
25 words
The method of claim 16 wherein said Lewis acid is selected from the group consisting of aluminum chloride, aluminum bromide, boron chloride, and gallium chloride.
Claim 20
Dependent Claim
29 words
The method of claim 12 further comprising the step: a) quenching the reaction of said reacting step by hydration of said Lewis acid prior to isolating the resulting product.
Claim 21
Dependent Claim
41 words
The method of claim 18 wherein said quenching step further comprises: a) adding absolute alcohol, wherein said absolute alcohol is at least one of methanol, ethanol or isopropanol; b) providing external cooling; c) transferring said reaction mixture to an aqueous mixture.
Claim 22
Dependent Claim
62 words
The method of claim 16 wherein said mixture comprises at least 1 mole of metal cyclopentadienide, at least 1 mole of arene, at least 0.5 mole of ferrous salt, at least 0.5 mole of a Lewis acid, at least 1 mole of a reducing agent wherein said reducing agent is one of aluminum, magnesium or zinc and optionally, an inert, non-polar diluent.
Claim 23
Dependent Claim
57 words
The method as recited in claim 16 wherein said cyclopentadienyliron (II) cation complex salt has the formula: ((Cp)--Fe--(Ar)).sup.+.sub.b X.sup.b- wherein Cp is an eta 5 complexed cyclopentadienyl anion, or an eta 5 complexed indenyl anion; Ar is an eta 6 complexed arene; X is an anion of valence b; and b is an integer 1,.2 or 3.
Claim 24
Dependent Claim
50 words
The method of claim 16 wherein said mixture comprises of at least 0.5 mole of anhydrous aluminum chloride, at least 0.25 g. atom of powdered aluminum, at least 0.25 mole of anhydrous ferrous chloride, at least 200 ml of an arene, wherein said arene is one of xylene or cumene.
Claim 25
Dependent Claim
63 words
The method of claim 22 for providing cyclopentadienyliron (II) arene cation complex salt further comprising: a) adding at least 0.25 mole of ammonium hexafluorophosphate or sodium hexafluoroantimonate to said product mixture prior to said isolating step, wherein one of cyclopentadienyliron (II) xylene hexafluorophosphate, cyclopentadienyliron (II) cumene hexafluorophosphate, cyclopentadienyliron (II) xylene hexafluoroantimonate or cyclopentadienyliron (II) cumene hexafluoroantimonate is precipitated; b) isolating said precipitated product.
References Cited (Backward Citations)
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