JP5470638B2 - Metallocene ionic liquid and method for producing the same - Google Patents

Description

  The present invention relates to a metallocene ionic liquid and a method for producing the same.

  In recent years, liquids having ionic properties at room temperature have attracted attention. Taking advantage of the volatile properties of ionic liquids such as non-volatility, flame retardancy, ionic conductivity, and heat resistance, for example, electrolytes for batteries such as lithium ion secondary batteries and fuel cells, solvents that utilize the symphoretic effect, catalysts, etc. It is expected to be used in the field.

  An ionic liquid is generally an ionic substance that is liquid at 100 ° C. or lower. For example, imidazolium salt derivatives, pyridinium salt derivatives, alkylammonium salt derivatives, phosphonium derivatives, and the like are known. For example, Non-Patent Documents 1 and 2 disclose ionic liquids in which a ferrocene moiety is introduced into an imidazole ring.

Ramjee Balasubramanian, 2 others, “Redox Ionic Liquid Phases: Ferrocenated Imidazoliums”, Journal of the American Chemical Society , (United States), American Chemical Society, August 9, 2006, Vol.128, No.31, p.9994-9995 Ye Gao, two others, “The First (Ferrocenylmethyl) imidazolium and (Ferrocenylmethyl) triazolium Room Temperature Ionic Liquids), Inorganic Chemistry, (United States), American Chemical Society, May 31, 2004, Vol. 43, No. 11, p. 3406-3412

  The type of ionic liquid and its characteristics are not yet fully known. The present inventors made it a subject to provide a novel metallocene type | system | group ionic liquid and its manufacturing method.

  The metallocene ionic liquid of the present invention is represented by the following general formula (1).

[Wherein, L ¹ and L ² may be the same or different from each other, and cyclopentadienyl ring, arene ring or derivatives thereof (at least one of L ¹ and L ² is a derivative having 1 to 12 carbon atoms) A linear alkyl group having 1 to 12 carbon atoms, a linear alkyl ether having 1 to 12 carbon atoms, a linear alkyl ester having 1 to 12 carbon atoms, and a halogen atom, provided that L ¹ and When L ² is a derivative and all hydrogen atoms in the ring structure are substituted with methyl groups, except when both L ¹ and L ² are tetramethylcyclopentadienyl rings); M ¹ is a transition Metal; X ⁻ represents a low symmetry anion. ]

L ¹ and L ² are preferably those represented by the following general formula (2) or (3).

[Wherein R ^{1 to} R ⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an ether group having 1 to 12 carbon atoms, or an ester having 1 to 12 carbon atoms. Represents a group. ]

[Wherein R ^{6 to} R ¹¹ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an ether group having 1 to 12 carbon atoms, or an ester having 1 to 12 carbon atoms. Represents a group. ]

M ¹ is preferably at least one metal atom selected from the group consisting of iron, cobalt, manganese, nickel, ruthenium, molybdenum, chromium, vanadium, titanium, rhodium, iridium, osmium and rhenium. X ⁻ represents at least one low symmetry selected from the group consisting of a bis (trifluoromethanesulfonyl) imide anion, a bis (heptafluoropropanesulfonyl) imide anion, and a bis (nonafluorobutanesulfonyl) imide anion. Anions are preferred.

  The present invention is a method for producing a metallocene ionic liquid represented by the following general formula (4), which is represented by the following metallocene derivative represented by the following general formula (5) and the following general formula (6). A method for producing a metallocene ionic liquid in which a silver salt is reacted is also included.

[Wherein M ¹ is a transition metal; R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. ˜12 ether group or C 1-12 ester group (provided that when R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all hydrogen atoms, R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all In the case of a methyl group, and R ²¹ and R ³¹ are hydrogen atoms, and R ^{22 to} R ²⁵ and R ^{32 to} R ³⁵ are each a methyl group); X ⁻ represents a low symmetric anion. ]

[Wherein, M ¹ , R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ have the same meanings as those in the general formula (4)].

[Wherein, X ⁻ has the same meaning as the above general formula (4)]

  According to the present invention, a novel metallocene-based ionic liquid can be obtained and expected to be used in the fields of battery electrolytes, solvents utilizing the symphoretic effect, catalysts, and the like.

  The metallocene ionic liquid of the present invention is characterized by comprising a compound represented by the following general formula (1).

[Wherein, L ¹ and L ² may be the same or different from each other, and cyclopentadienyl ring, arene ring or derivatives thereof (at least one of L ¹ and L ² is a derivative having 1 to 12 carbon atoms) A linear alkyl group having 1 to 12 carbon atoms, a linear alkyl ether having 1 to 12 carbon atoms, a linear alkyl ester having 1 to 12 carbon atoms, and a halogen atom, provided that L ¹ and L ² is a derivative and all hydrogen atoms in the ring structure are substituted with methyl groups, except for compounds in which both L ¹ and L ² are tetramethylcyclopentadienyl rings); M ¹ is a transition Metal; X ⁻ represents a low symmetry anion. ]

  As shown in the general formula (1), the metallocene ionic liquid of the present invention is characterized by using a cation shown in the following general formula (7) as a cation. Thus, by using a substituted metallocenium cation or the like as a cation, an ionic liquid can be realized without introducing an imidazole skeleton into the molecule. In the present invention, the ionic liquid refers to an ionic substance having a melting point of 100 ° C. or lower.

[Wherein, L ¹ , L ² , and M ¹ have the same meaning as in the above formula (1). ]

The cyclopentadienyl ring derivative or arene ring derivative represented by L ¹ or L ² is a linear alkyl group having at least one hydrogen atom of the cyclopentadienyl ring or arene ring, having 1 to 12 carbon atoms, It is substituted with at least one substituent selected from the group consisting of linear alkyl ethers having 1 to 12 carbon atoms, linear alkyl esters having 1 to 12 carbon atoms and halogen atoms. Here, specific examples of the arene ring include, for example, benzene, pentalene, indene and the like.

  Examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-amyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. , N-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group and the like linear alkyl groups; i-propyl group, i-butyl group, s-butyl group, t-butyl group, i-amyl And branched alkyl groups such as t-amyl group. Examples of the ether group having 1 to 12 carbon atoms include linear alkyl ether groups such as methyl ether group, ethyl ether group, n-propyl ether group, n-butyl ether group and n-pentyl ether group; . Examples of the ester group having 1 to 12 carbon atoms include linear alkyl ester groups such as a methyl ester group, an ethyl ester group, an n-propyl ester group, an n-butyl ester group, and an n-pentyl ester group; It is done.

The combination of L ¹ and L ² is not particularly limited, but at least one of them must be a derivative in which at least one of the hydrogen atoms of the ring structure is substituted, and both L ¹ and L ² are Embodiments of derivatives in which all hydrogen atoms of the ring structure are substituted with methyl groups; and embodiments in which both L ¹ and L ² are tetramethylcyclopentadienyl rings are excluded. When both L ¹ and L ² are unsubstituted, when both L ¹ and L ² are derivatives in which all hydrogen atoms of the ring structure are substituted with methyl groups, and L ¹ and L ² When both are tetramethylcyclopentadienyl rings, the melting point of the obtained metallocene ionic substance becomes very high, and an ionic liquid cannot be obtained.

For example, when both L ¹ and L ² are a cyclopentadienyl ring (unsubstituted metallocenium cation), a pentamethylcyclopentadienyl ring (decamethyl metallocenium cation), or tetramethyl In the case of a cyclopentadienyl ring (octamethyl metallocenium cation), the melting point of the resulting compound exceeds 100 ° C. The melting point of the compound using the unsubstituted metallocenium cation is, for example, 129 ° C. for the ferrocenebis (trifluoromethanesulfonyl) imide anion salt ([Cp ₂ Fe] [NTf ₂ ]), and cobaltsenbis (trifluoromethanesulfonyl). ) The melting point of imide anion salt ([Cp ₂ Co] [NTf ₂ ]) is 165.9 ° C. Melting points of compounds using decamethyl metallocenium cation, such as decamethyl ferrocene bis (trifluoromethanesulfonyl) imide anion salt ([(Me ₅ Cp) ₂ Fe] [NTf ₂ ]) and decamethyl cobalt senbis (trifluoro) The melting point of the lomethanesulfonyl) imide anion salt ([(Me ₅ Cp) ₂ Co] [NTf ₂ ]) is 200 ° C. or higher. The melting point of the compound using the octamethyl metallocenium cation, for example, the melting point of octamethylferrocenebis (trifluoromethanesulfonyl) imide anion salt ([(Me ₄ HCp) ₂ Fe] [NTf ₂ ]) is 223 ° C. .

It is preferable that at least one of the L ¹ and L ² is a derivative and has at least one linear alkyl group having 2 to 4 carbon atoms as a substituent. More preferably, both of L ¹ and L ² are derivatives, and each has at least one linear alkyl group having 2 to 4 carbon atoms as a substituent.

Examples of the L ^1, L ^2, preferably one represented by the following general formula (2) or (3).

[Wherein R ^{1 to} R ⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an ether group having 1 to 12 carbon atoms, or an ester having 1 to 12 carbon atoms. Represents a group. ]

[Wherein R ^{6 to} R ¹¹ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an ether group having 1 to 12 carbon atoms, or an ester having 1 to 12 carbon atoms. Represents a group. ]

  That is, examples of the substituted metallocene cation constituting the metallocene ionic liquid of the present invention include a substituted metallocenium cation represented by the following formula (8), a monoarene-substituted metallocene cation represented by the following formula (9), and the following: A bisarene-substituted metallocene cation represented by the formula (10) is preferred.

[Wherein M ¹ is a transition metal; R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. ˜12 ether group or C 1-12 ester group (provided that when R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all hydrogen atoms, R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all In the case of a methyl group, and R ²¹ and R ³¹ are hydrogen atoms, and R ^{22 to} R ²⁵ and R ^{32 to} R ³⁵ are each a methyl group). ]

[Wherein, M ¹ is a transition metal; R ^{21 to} R ²⁵ and R ^{31 to} R ³⁶ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. -12 ether group or C1-12 ester group (provided that R ^{21 to} R ²⁵ and R ^{31 to} R ³⁶ are all hydrogen atoms and R ^{21 to} R ²⁵ and R ^{31 to} R ³⁶ are all methyl groups. Except the case of). ]

[Wherein, M ¹ is a transition metal; R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. -12 ether group or C1-12 ester group (provided that R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ are all hydrogen atoms and R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ are all methyl groups. Except the case of). ]

Specific examples of the substituted metallocenium cation represented by the general formula (8) include 1,1′-dimethylferrocenium cation (hereinafter “[Me ₂ Fc] ⁺ ”), ethylferrocenium cation ( Hereinafter, “[EtFc] ⁺ ”), 1,1′-diethylferrocenium cation (hereinafter “[Et ₂ Fc] ⁺ ”), n-butylferrocenium cation (hereinafter “[n-BuFc] ⁺ ”). )), 1,1′-dibutylferrocenium cation (hereinafter “[n-Bu ₂ Fc] ⁺ ”), t-butylferrocenium cation (hereinafter “[t-BuFc] ⁺ ”), t− Amylferrocenium cation (hereinafter “[AmFc] ⁺ ”), Butyloctamethylferrocenium cation (hereinafter “[(CpMe ₄ C ₄ H ₉ ) (CpMe ₄ H) Fe] ⁺ ”), iodoferroce Nikkachi Down (hereinafter, "[IFc] ^+") substituted ferrocenium ion and the like; 1,1'-diethyl cobalt Se cation (hereinafter, "[(EtCp) ₂ Co] ^+") substituted cobalt-ion-like Is mentioned.

Specific examples of the monoarene-substituted metallocene cation represented by the general formula (9) include (ethylbenzene) (cyclopentadienyl) iron (1+) (hereinafter referred to as “[(C ₆ H ₅ Et) CpFe] ⁺ ”). ), (Benzene) (ethylcyclopentadienyl) iron (1+) (hereinafter “[(C ₆ H ₆ ) (EtCp) Fe] ⁺ ”), (ethylbenzene) (ethylcyclopentadienyl) iron (1+) (Hereinafter, [(C ₆ H ₅ Et) (EtCp) Fe] ⁺ ) and the like may be mentioned.

Specific examples of the bisarene-substituted metallocene cation represented by the general formula (10) include bis (ethylbenzene) chromium (1+) (hereinafter referred to as [(C ₆ H ₅ Et) ₂ Cr] ⁺ )). .

The metal atom represented by M ¹ is not particularly limited as long as it is a transition metal. Among these, at least one selected from the group consisting of iron, cobalt, manganese, nickel, ruthenium, molybdenum, chromium, vanadium, titanium, rhodium, iridium, osmium, and rhenium is preferable. The metal atom represented by M ¹ is preferably different depending on the structures of L ¹ and L ^2. For example, if the substituted metallocenium cation represented by the general formula (8) is used, iron or cobalt Is preferred. Here, when the metal constituting the substituted metallocenium cation has an odd number of electrons, the metallocenium-based ionic liquid exhibits magnetism, and the resulting ionic liquid becomes a magnetic fluid. Therefore, in the substituted metallocenium cation represented by the general formula (8), iron is particularly preferable as the metal represented by M ¹ . Moreover, when the metal which comprises the substituted metallocenium cation represented by the said General formula (8) is cobalt, the obtained ionic liquid becomes very stable with respect to oxygen.

  If it is a monoarene substituted metallocene cation represented by the general formula (9), iron, ruthenium or osmium is preferable. If it is a bisarene substituted metallocene cation represented by the general formula (9), chromium, molybdenum or rhenium is preferable.

The low symmetric anion represented by X ⁻ is not particularly limited as long as the molecule has a shape other than spherical symmetry, linear shape, regular tetrahedral shape, and regular octahedral shape and has low symmetry. Examples of the low symmetric anion include a low symmetric anion having a fluorine atom and a low symmetric anion having a cyano group. The reason why a low symmetric anion is used as the anion constituting the ionic liquid of the present invention is that an anion having a highly symmetrical molecule (for example, I ³⁻ , BF ⁴⁻ , PF ^6−, etc.) is used as the anion. This is because the resulting compound tends to have a high melting point. The melting point of a compound using an anion having a highly symmetric shape is, for example, 1,1′-diethylcobaltennium hexafluorophosphate ([(EtCp) ₂ Co] [PF ₆ ]) having a melting point of 148 ° C. It is.

Examples of the low symmetric anion having a fluorine atom include a bis (trifluoromethanesulfonyl) imide anion (hereinafter, “[NTf ₂ ] ⁻ ”) (the following formula (11a)), a bis (heptafluoropropanesulfonyl) imide anion ( Hereinafter, “[NHf ₂ ] ⁻ ”) (the following formula (11b)), bis (nonafluorobutanesulfonyl) imide anion (hereinafter “[NNf ₂ ] ⁻ ”) (the following formula (11c)), cyclo-hexafluoro Imide type anions such as propane-1,3-bis (sulfonyl) imide (the following formula (11d)); trifluoromethanesulfonic acid anion (the following formula (12a)), nonafluorobutanesulfonic acid anion (the following formula (12b)) Sulfonate anions such as: trifluoroacetate anion (following formula (13a)), pentafur Ropuropion anion (formula (13b)), heptafluoro butyrate (formula (13c)) carboxylate-based anions such as; and the like.

Examples of the low symmetric anion having a cyano group represented by X ⁻ include a dicyanoamine anion (the following formula (14a)) and a tricyanomethane anion (the following formula (14b)).

Among these, as the anion represented by X ⁻ , a low symmetric anion having a fluorine atom is preferable, and [NTf ₂ ] ⁻ , [NHf ₂ ] ⁻ and [NNf ₂ ] ⁻ are particularly preferable.

  Examples of the metallocene ionic liquid of the present invention include those represented by the following formulas (4), (15) and (16).

[Wherein M ¹ is a transition metal; R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. ˜12 ether group or C 1-12 ester group (provided that when R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all hydrogen atoms, R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all In the case of a methyl group, and R ²¹ and R ³¹ are hydrogen atoms, and R ^{22 to} R ²⁵ and R ^{32 to} R ³⁵ are each a methyl group); X ⁻ represents a low symmetric anion. ]

[Wherein, M ¹ is a transition metal; R ^{21 to} R ²⁵ and R ^{31 to} R ³⁶ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. -12 ether group or C1-12 ester group (provided that R ^{21 to} R ²⁵ and R ^{31 to} R ³⁶ are all hydrogen atoms and R ^{21 to} R ²⁵ and R ^{31 to} R ³⁶ are all methyl groups. X ⁻ represents a low symmetry anion. ]

[Wherein, M ¹ is a transition metal; R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. -12 ether group or C1-12 ester group (provided that R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ are all hydrogen atoms and R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ are all methyl groups. X ⁻ represents a low symmetry anion. ]

Formula (4), (15) and (16), substituents wherein the ring structure has (formula (4), the ^{R 21 ~R 25, R 31 ~R} 35, in Formula (15) R ²¹ to R ²⁵ , R ^{31 to} R ³⁶ and R ^{21 to} R ²⁶ and R ^{31 to} R ³⁶ ) in the formula (16) are preferably a linear alkyl group having at least one of 2 to 4 carbon atoms. In the general formulas (4), (15) and (16), at least one of R ^{21 to} R ²⁵ or R ^{21 to} R ²⁶ is a linear alkyl group having 2 to 4 carbon atoms, and the R It is particularly preferred that at least one of ^{31 to} R ³⁵ or R ^{31 to} R ³⁶ is a linear alkyl group having 2 to 4 carbon atoms.

Incidentally, the case M ¹ in the general formula (4) is an iron atom, for the resulting compound is unstable to a little oxygen, in order to stabilize against oxygen R ²¹ ~R ^25, R ³¹ to R ³⁵ is preferably a plurality of alkyl groups, e.g., butyl octamethyl body (R ²¹ = n-butyl group, R ³¹ = hydrogen ^{atom, R 22 ~R 25, R 32} ~R 35 = methyl group) Etc. are suitable.

Specific examples of the compound represented by the general formula (4) include 1,1′-dimethylferrocenium bis (trifluoromethanesulfonyl) imide salt (hereinafter, “[Me ₂ Fc] [NTf ₂ ]”), Ethylferrocenium bis (trifluoromethanesulfonyl) imide salt (hereinafter, “[EtFc] [NTf ₂ ]”), 1,1′-diethylferrocenium bis (trifluoromethanesulfonyl) imide salt (hereinafter, “[Et ₂ Fc] [NTf ₂ ] ”), n-butylferrocenium bis (trifluoromethanesulfonyl) imide salt (hereinafter“ [n-BuFc] [NTf ₂ ] ”), 1,1′-di-n-butylferro Seniumubisu (trifluoromethanesulfonyl) imide salt (hereinafter, _{"[n-Bu 2 Fc] [} NTf 2] "), t-butyl ferrocenium bis (trifluoperazine ) Imide salt (hereinafter, _{"[t-BuFc] [NTf 2} ] "), t-amyl ferrocenium bis (trifluoromethanesulfonyl) imide salt (hereinafter, "[AmFc] [NTf _2]"), butyl Octamethylferrocenium bis (trifluoromethanesulfonyl) imide salt (hereinafter, “[(CpMe ₄ C ₄ H ₉ ) (CpMe ₄ H) Fe] [NTf ₂ ]”), iodoferrocenium bis (trifluoromethanesulfonyl) Imide salt (hereinafter “[IFc] [NTf ₂ ]”), 1,1′-diethylcobaltennium bis (trifluoromethanesulfonyl) imide salt (hereinafter “[(EtCp) ₂ Co] [NTf ₂ ]”) , 1,1′-diethylcobaltennium bis (heptafluoropropanesulfonyl) imide salt (hereinafter referred to as “[(EtCp) ₂ C o] [NHf ₂ ] ”), 1,1′-diethylcobaltennium bis (nonafluorobutanesulfonyl) imide salt (hereinafter“ [(EtCp) ₂ Co] [NNf ₂ ] ”) and the like.

Specific examples of the compound represented by the general formula (15) include (ethylbenzene) (cyclopentadienyl) iron (1+) bis (trifluoromethanesulfonyl) imide salt (hereinafter referred to as “[(C ₆ H ₅ Et) CpFe] [NTf ₂ ] ”), (benzene) (ethylcyclopentadienyl) iron (1+) bis (trifluoromethanesulfonyl) imide salt (hereinafter“ [(C ₆ H ₆ ) (EtCp) Fe] [NTf ₂ ] "), (Ethylbenzene) (ethylcyclopentadienyl) iron (1+) bis (trifluoromethanesulfonyl) imide salt (hereinafter referred to as [(C ₆ H ₅ Et) (EtCp) Fe] [NTf ₂ ]"). It is done.

Specific examples of the compound represented by the general formula (16) include bis (ethylbenzene) chromium (1+) bis (trifluoromethanesulfonyl) imide salt (hereinafter referred to as [(C ₆ H ₅ Et) ₂ Cr] [NTf ₂ ])) And the like.

  Hereinafter, the manufacturing method of the metallocene ionic liquid of this invention is demonstrated.

  First, a method for producing a metallocene ionic liquid represented by the general formula (4) will be described.

  This production method is characterized in that a metallocene derivative represented by the following general formula (5) is reacted with a silver salt represented by the following general formula (6).

[Wherein, M ¹ , R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ have the same meanings as those in the general formula (4)].

[Wherein, X ⁻ has the same meaning as the above general formula (4)]

  In this reaction, the metallocene ionic liquid of the present invention is obtained by oxidizing the metal atoms constituting the metallocene derivative with the silver salt. An example of a synthesis scheme of a ferrocene-based ionic liquid is shown below.

  The metallocene derivative used in the production method is not particularly limited as long as it can form the substituted metallocenium cation represented by the general formula (8). Examples of the metallocene derivatives include 1,1′-dimethylferrocene, ethylferrocene, 1,1′-diethylferrocene, n-butylferrocene, 1,1′-dibutylferrocene, t-butylferrocene, t-amylferrocene, butyl. And ferrocene derivatives such as octamethylferrocene and iodoferrocene.

The silver salt represented by the general formula (6) used in this production method (hereinafter sometimes simply referred to as a silver salt) is not particularly limited as long as it is a salt composed of the anion and silver described above. Examples of the silver salt include a silver salt of a bis (trifluoromethanesulfonyl) imide anion (hereinafter “AgNTf ₂ ”), a silver salt of a bis (heptafluoropropanesulfonyl) imide anion (hereinafter “AgNHf ₂ ”), a bis Examples thereof include a silver salt of (nonafluorobutanesulfonyl) imide anion (hereinafter, “AgNNf ₂ ”).

  In this production method, the charging ratio (molar ratio) between the metallocene derivative and the silver salt is preferably 1.01 mol or more and 1.05 mol or less with respect to 1 mol of the metallocene derivative. By setting the charging ratio within the above range, a high purity ionic liquid can be obtained. The reaction may be performed at room temperature. In addition, it is preferable to perform all reaction operation of a metallocene derivative and silver salt under inert atmosphere.

  Examples of a mode in which the metallocene derivative is reacted with the silver salt include a solventless reaction or a liquid phase reaction, but a solventless reaction is preferable because it can be performed more simply and rapidly. In addition, when the ionic liquid obtained is a solid salt at room temperature, it is preferable to employ a liquid phase reaction.

  In the case of a solvent-free reaction, a solid or liquid state metallocene derivative and a silver salt may be simply mixed. The mixing method is not particularly limited, and for example, mixing may be performed using an agate mortar. In the case of a solventless reaction, after the reaction, the produced ionic liquid is filtered, and the ionic liquid is obtained by removing silver as a by-product and unreacted silver salt.

  In the case of a liquid phase reaction, the metallocene derivative and the silver salt may be dissolved in a solvent and then mixed and stirred. As the solvent, acetone, acetonitrile, ethanol or the like may be used. The solvent is preferably bubbled with nitrogen before use.

  When the liquid phase reaction is employed, it is necessary to remove by-product silver, unreacted silver salt and solvent from the reaction solution after the reaction. Silver as a by-product can be removed by filtering the reaction solution. Unreacted silver salt can be removed by washing the reaction solution with a washing solution that dissolves only the silver salt without dissolving the ionic liquid. As the cleaning liquid, hexane, pentane, or the like may be used. In order to facilitate washing of the reaction solution, it is preferable to concentrate the reaction solution under reduced pressure before washing. The solvent can be removed by reducing the pressure of the reaction solution.

  In addition, when a liquid phase reaction is employed, impurities such as decomposition products may remain in the obtained ionic liquid, and thus it is preferable to purify by recrystallization. The solvent and poor solvent used for recrystallization are not particularly limited, and may be appropriately selected depending on the ionic liquid. Examples of the solvent used for recrystallization include a diethyl ether / acetone mixed solvent, and examples of the poor solvent include pentane.

  Next, the anion exchange reaction of the metallocenium salt will be described. In this production method, the ionic liquid of the present invention is obtained by bringing the metallocenium salt into contact with the salt of the anion and exchanging the anion. An example of a synthesis scheme of a cobaltocene ionic liquid is shown below.

  The metallocenium salt used in this production method is not particularly limited as long as it is a salt of the aforementioned substituted metallocenium cation. Examples of the metallocenium salt include cobalt cenium salts such as 1,1'-diethyl cobalt cene hexafluorophosphate;

The anion salt is not particularly limited. For example, lithium bis (trifluoromethanesulfonyl) imide salt (hereinafter “LiNTf ₂ ”), lithium bis (heptafluoropropanesulfonyl) imide salt (hereinafter “LiNHf ₂ ”). And lithium bis (nonafluorobutanesulfonyl) imide salt (hereinafter referred to as “LiNNf ₂ ”).

  In this production method, the charging ratio (molar ratio) between the metallocenium salt and the anion salt is preferably 1.5 mol or more and 2 mol or less of the anion salt with respect to 1 mol of the metallocenium salt. The reaction may be performed at 20 to 100 ° C.

  In addition, the method of anion exchange reaction is not specifically limited, For example, after dissolving a metallocenium salt and an anion salt in a solvent, both may be mixed and stirred.

  Next, a method for producing the metallocene ionic liquid represented by the general formula (15) will be described. The method for producing the metallocene ionic liquid represented by the general formula (15) is not particularly limited, and may be appropriately selected depending on the desired ionic liquid. For example, one of the cyclopentadienyl rings of the metallocene is substituted with an arene ring to obtain a salt of a monoarene complex, and then anion exchange is performed.

  Next, a method for producing the metallocene ionic liquid represented by the general formula (16) will be described. The metallocene-based ionic liquid represented by the general formula (16) is a neutral bisarene complex (for example, chromium, manganese, etc. as a constituent metal) which is halogen-oxidized to perform anion exchange, or a silver salt. The method of oxidizing is mentioned. Synthesis examples of compounds similar to the metallocene-based ionic liquid of the present invention are described in, for example, F. Grepioni, G. Cojazzi, SM Draper, N. Scully, D. Braga, Organometallics, 17, 296 (1998). You can refer to these.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

Evaluation method 1. Melting point and glass transition temperature The melting point and glass transition temperature of the ionic liquids obtained in Production Examples 2, 3, 4, 5, 9, 10, 11, 12, 13, 14, and 15 were measured with a differential scanning calorimeter (TEA). -It measured using instrument company make, "Q100 type". The measurement conditions were a measurement temperature range of −160 ° C. to 60 ° C. and a temperature increase rate of 10 Kmin ⁻¹ .
The melting points of the ionic liquids obtained in Production Examples 1, 6, 7, and 8 were measured using a melting point measuring device (manufactured by Electrothermal, MEL-TEMP, “FU8E type”). The measurement conditions were that the temperature was gradually raised from room temperature in the atmosphere, and the temperature was visually read using a mercury thermometer.

2. Viscosity The viscosity of the ionic liquid was measured at 25 ° C. using a viscometer (manufactured by Toki Sangyo Co., Ltd., TV-22L). The measurement conditions were rotor No. 7 (3 ′ × R7.7) was used, and the rotation speed was 100 rpm.

3. Molar magnetic susceptibility The molar magnetic susceptibility of the ionic liquid was measured using a physical property measuring apparatus (manufactured by Quantum Design, PPMS). As measurement conditions, a sample of 128 mg to 172 mg was used in a temperature range of 300 K to 2 K and a magnetic field of 0.1 T to 5 T.

4). Elemental analysis Elemental analysis values were measured using a CHN coder (manufactured by Yanaco Analytical Industry, MT-5).

5. ¹ HNMR
Using deuterated chloroform (CDCl _3), it was measured by a nuclear magnetic resonance apparatus (JEOL Ltd., JNM-ECL-400). Chemical shifts were recorded from tetramethylsilane (SiMe ₄ ) as parts per million (ppm; δ scale) on the low magnetic field side, and tetramethylsilane (δ = 0) was referenced.

Production and production example 1 of metallocene ionic liquid ([Me ₂ Fc] [NTf ₂ ])
All the solvents used were nitrogen bubbled, and all experiments were performed under a nitrogen atmosphere. An acetone solution of 467 mg (1.20 mmol) of AgNTf _{2 was} added dropwise to an acetone solution (10 mL) of 260 mg (1.21 mmol) of 1,1′-dimethylferrocene with stirring. The solution was stirred at room temperature for 1 hour. After removing the precipitated silver with a syringe filter, the solution was concentrated under reduced pressure. This solution was washed several times with hexane until no color was formed, and then the solution was dried under reduced pressure to obtain the target substance. Recrystallization was performed by diffusing a poor solvent (pentane) into the diethyl ether / acetone mixed solvent of this salt to obtain [Me ₂ Fc] [NTf ₂ ]. The melting point of the obtained [Me ₂ Fc] [NTf ₂ ] was measured. The results are shown in Table 1.

Production Example 2 ([EtFc] [NTf ₂ ])
All operations were performed under a nitrogen atmosphere. AgNTf ₂ 788 mg (2.03 mmol) was added to ethyl ferrocene 425 mg (1.99 mmol), and the mixture was mixed for about 10 minutes in an agate mortar. The dark blue liquid formed was filtered through a syringe filter to remove AgNTf ₂ of silver and unreacted. By this operation, [EtFc] [NTf ₂ ] was obtained almost quantitatively. The melting point, viscosity, and molar magnetic susceptibility of the obtained [EtFc] [NTf ₂ ] were measured. The results are shown in Table 1.

Production Example 3 ([Et ₂ Fc] [NTf ₂ ])
[Et _{2] In the same} manner as in Production Example 2, except that ethylferrocene was changed to 374 mg (1.54 mmol) of 1,1′-diethylferrocene and the addition amount of AgNTf ₂ was changed to 615 mg (1.59 mmol). Fc] [NTf ₂ ] was prepared. Elemental analysis values of the obtained [Et ₂ Fc] [NTf ₂ ] were C36.73 mass%, H3.52 mass%, N2.67 mass% (calculated values C36.79 mass%, H3.47 mass%, N2.68% by mass). The melting point, viscosity, and molar magnetic susceptibility of the obtained [Et ₂ Fc] [NTf ₂ ] were measured. The results are shown in Table 1.

Production Example 4 ([n-BuFc] [NTf ₂ ])
Except that the ethylferrocene was changed to 256 mg (1.05 mmol) of n-butylferrocene and the addition amount of AgNTf ₂ was changed to 414 mg (1.07 mmol), a dark blue liquid [ n-BuFc] [NTf ₂ ] was prepared. Elemental analysis values of the obtained [n-BuFc] [NTf ₂ ] were C36.72% by mass, H3.69% by mass, N2.82% by mass (calculated values C36.79% by mass, H3.47% by mass, N2.68% by mass). The glass transition temperature, viscosity, and molar magnetic susceptibility of the obtained [n-BuFc] [NTf ₂ ] were measured. The results are shown in Table 1.

Production Example 5 ([n-Bu ₂ Fc] [NTf ₂ ])
Except that ethylferrocene was changed to 314 mg (1.05 mmol) of 1,1′-di-n-butylferrocene and the addition amount of AgNTf ₂ was changed to 439 mg (1.13 mmol), the same as in Production Example 2 [N-Bu ₂ Fc] [NTf ₂ ] was produced. Elemental analysis values of the obtained [n-Bu ₂ Fc] [NTf ₂ ] were C38.90% by mass, H4.50% by mass, N2.52% by mass (calculated values C39.14% by mass, H4.38% by mass). %, N2.54 mass%). The melting point, glass transition temperature, viscosity, and molar magnetic susceptibility of the obtained [n-Bu ₂ Fc] [NTf ₂ ] were measured. The results are shown in Table 1.

Production Example 6 ([t-BuFc] [NTf ₂ ])
Except that 1,1′-dimethylferrocene was changed to 166 mg (0.686 mmol) of t-butylferrocene and the addition amount of AgNTf ₂ was changed to 264 mg (0.679 mmol), the same as in Production Example 1 [ t-BuFc] [NTf ₂ ] was prepared. Elemental analysis values of the obtained [t-BuFc] [NTf ₂ ] were C36.72% by mass, H3.69% by mass, N2.82% by mass (calculated values C36.79% by mass, H3.47% by mass, N2.68% by mass). The melting point of the obtained [t-BuFc] [NTf ₂ ] was measured. The results are shown in Table 1.

Production Example 7 ([AmFc] [NTf ₂ ])
Except that 1,1′-dimethylferrocene was changed to 208 mg (0.812 mmol) of t-amylferrocene and the addition amount of AgNTf ₂ was changed to 318 mg (8.20 mmol), the same as in Production Example 1 [ AmFc] [NTf ₂ ] was prepared. The melting point of the obtained [AmFc] [NTf ₂ ] was measured. The results are shown in Table 1.

Production Example 8 ([(CpMe ₄ C ₄ H ₉ ) (CpMe ₄ H) Fe] [NTf ₂ ])
Except that 1,1′-dimethylferrocene was changed to 60.4 mg (0.18 mmol) of butyloctamethylferrocene and the addition amount of AgNTf ₂ was changed to 76.0 mg (0.20 mmol), Production Example 1 and In the same manner, [(CpMe ₄ C ₄ H ₉ ) (CpMe ₄ H) Fe] [NTf ₂ ] was produced. The melting point of the obtained [(CpMe ₄ C ₄ H ₉ ) (CpMe ₄ H) Fe] [NTf ₂ ] was measured. The results are shown in Table 1.

Production Example 9 ([IFc] [NTf ₂ ])
[IFc] [NTf ₂ ] was changed in the same manner as in Production Example 2 except that ethylferrocene was changed to 116 mg (0.371 mmol) of iodoferrocene and the addition amount of AgNTf ₂ was changed to 146 mg (0.376 mmol). Manufactured. It was confirmed that the melting point of the obtained [IFc] [NTf ₂ ] was not more than room temperature.

Production Example 10 ([(EtCp) ₂ Co] [NTf ₂ ])
All operations were performed in air. 326 mg (0.837 mmol) of 1,1′-diethylcobaltene hexafluorophosphate ([(EtCp) ₂ Co] [PF ₆ ]) was dissolved in a small amount of water in a boiling state. An excess amount of 510 mg (1.78 mmol) aqueous solution of LiNTf ₂ was added dropwise, and the mixture was heated and stirred for 30 minutes as it was, returned to room temperature and centrifuged, and after removing the aqueous phase, ether was added as a solvent. This ether solution was washed several times with water and dried over magnesium sulfate, and after removing the desiccant by filtration, the solvent was removed under reduced pressure, followed by vacuum heating and drying at 90 ° C. for 1 day. Through the above operation, [(EtCp) ₂ Co] [NTf ₂ ] was obtained almost quantitatively as an orange liquid, and the elemental analysis value of the obtained [(EtCp) ₂ Co] [NTf ₂ ]. C36.60 Mass%, H 3.48 mass%, N 2.72 mass% (calculated value C 36.58 mass%, H 3.45 mass%, N 2.67 mass%). [[EtCp) ₂ Co] [ The melting point and viscosity of NTf ₂ ] were measured and the results are shown in Table 1.

Production Example 11 ([(EtCp) ₂ Co] [NHf ₂ ])
The LiNTf _2, except changing the LiNHf ₂ 712mg (1.46mmol) got in the same manner as in Preparation Example _{10 [(EtCp) 2 Co]} [NHf 2]. The elemental analysis values of the obtained [(EtCp) ₂ Co] [NHf ₂ ] were as follows: C33.33% by mass, H2.75% by mass, N2.09% by mass (calculated values C33.12% by mass, H2.50% by mass). %, N1.93 mass%). The melting point and glass transition temperature of the obtained [(EtCp) ₂ Co] [NHf ₂ ] were measured. The results are shown in Table 1.

Production Example 12 ([(EtCp) ₂ Co] [NNf ₂ ])
The LiNTf _2, except changing the LiNNf ₂ 885mg (1.51mmol) got in the same manner as in Preparation Example _{10 [(EtCp) 2 Co]} [NNf 2]. It was confirmed that the melting point of the obtained [(EtCp) ₂ Co] [NNf ₂ ] was not more than room temperature.

Production Example 13 ([(C ₆ H ₅ Et) CpFe] [NTf ₂ ])
All the following operations were performed under light shielding. Ferrocene (300.8 mg, 1.613 mmol) was placed in a three-necked flask and substituted with N ₂ . Anhydrous ethylbenzene (10 mL) was added thereto to dissolve ferrocene. AlCl ₃ (430.2 mg, 3.226 mmol) was added thereto and stirred at room temperature for 30 minutes, followed by stirring at 100 ° C. for 1 hour, and aluminum powder (40.0 mg, 1.481 mmol) was added. Thereafter, the mixture was refluxed at 140 ° C. for 10 hours. Water was added to the system and stirring was continued for another hour. The reaction mixture was filtered and the filtrate was washed 3 times with ethyl acetate and once with hexane. An aqueous solution of LiNTf ₂ (483.6 mg, 1.684 mmol) was added to the obtained aqueous layer and stirred for 1 hour.

Dichloromethane was added to the system to separate it into an aqueous layer and an organic layer. The organic layer was washed with water until no emulsion was formed, and then the dichloromethane layer was dried over MgSO ₄ . After the desiccant was filtered off, the solvent was removed. The crude product was purified on an alumina column using dichloromethane as the solvent. After removing the solvent, recrystallization was performed from ethanol / methanol (volume ratio 2: 1) in a freezer at −50 ° C. The crystals were collected by suction filtration and dried in vacuo. The obtained [(C ₆ H ₅ Et) CpFe] [NTf ₂ ] was 300.3 mg of yellow fine crystals, and the yield was 36.7%.

Elemental analysis values of the obtained [(C ₆ H ₅ Et) CpFe] [NTf ₂ ] were C 35.42% by mass, H 3.04% by mass, N 3.00% by mass (calculated values C 35.52% by mass, H 2 .98 mass%, N 2.76 mass%). ¹ HNMR data are (400 MHz, CDCl ₃ , TMS): δ = 1.33 (t, 3H, J = 7.5), 2.77 (q, 2H, J = 7.5), 5.01 (S, 5H), 6.23 (m, 5H). The melting point of the obtained [(C ₆ H ₅ Et) CpFe] [NTf ₂ ] was measured. The results are shown in Table 1.

Production Example 14 ([(C ₆ H ₆ ) (EtCp) Fe] [NTf ₂ ])
Ferrocene was changed to 1,1′-diethylferrocene (243.7 mg, 1.006 mmol) and anhydrous ethylbenzene was changed to anhydrous benzene (10 mL), and the amount of each reagent added was changed to AlCl ₃ (268.3 mg, 2 0.012 mmol), aluminum powder (24.6 mg, 0.913 mmol), LiNTf ₂ (316.4 mg, 1.102 mmol). [(C ₆ H ₆ ) (EtCp) Fe] [NTf ₂ ] was produced in the same manner as in Production Example 13 except for this change. Elemental analysis values of the obtained [(C ₆ H ₆ ) (EtCp) Fe] [NTf ₂ ] are C35.27 mass%, H3.00 mass%, N3.13 mass% (calculated value C35.52 mass%, H2.98 mass%, N 2.76 mass%). ¹ HNMR data are (400 MHz, CDCl ₃ , TMS): δ = 1.19 (t, 3H, J = 7.5), 2.42 (q, 2H, J = 7.5), 5.03 (S, 4H), 6.24 (s, 6H). The melting point of the obtained [(C ₆ H ₆ ) (EtCp) Fe] [NTf ₂ ] was measured. The results are shown in Table 1.

Production Example 15 ([(C ₆ H ₅ Et) (EtCp) Fe] [NTf ₂ ])
Ferrocene was changed to 1,1′-diethylferrocene (305.2 mg, 1.260 mmol), and the addition amount of each reagent was changed accordingly to anhydrous ethylbenzene (15 mL), AlCl ₃ (386.6 mg, 2.899 mmol), The powder was changed to aluminum powder (33.5 mg, 1.243 mmol) and LiNTf ₂ (468.6 mg, 1.632 mmol). Except for this change, [(C ₆ H ₅ Et) (EtCp) Fe] [NTf ₂ ] was produced in the same manner as in Production Example 13. Since the obtained [(C ₆ H ₅ Et) (EtCp) Fe] [NTf ₂ ] is a liquid at room temperature, it is purified by an alumina column (CH ₂ Cl ₂ ), and is not recrystallized. Heat drying (80 ° C., 12 hours) was performed.

Elemental analysis values of the obtained [(C ₆ H ₅ Et) (EtCp) Fe] [NTf ₂ ] were C 38.52 mass%, H 3.88 mass%, N 2.88 mass% (calculated value C 38.14 mass%). H3.53 mass%, N2.62 mass%). The melting point of the obtained [(C ₆ H ₅ Et) (EtCp) Fe] [NTf ₂ ] was measured. The results are shown in Table 1.

  The metallocene ionic liquid of the present invention can be used for a solvent and an electrolytic solution as in the conventional ionic liquid. The metallocene ionic liquid of the present invention can be used as an oxidation reaction reagent when an iron atom or the like is used as a metal atom constituting the metallocenium cation. The metallocene-based ionic liquid of the present invention is used for magnetic fluids, MR fluids, magnetic recording media and the like because the resulting compound exhibits magnetism when an iron atom or the like is used as the metal atom constituting the metallocenium-based cation. be able to.

Claims (7)

A metallocene-based ionic liquid represented by the following general formula (1):
[Wherein, L ¹ and L ² may be the same or different from each other, and cyclopentadienyl ring, arene ring or derivatives thereof (at least one of L ¹ and L ² is a derivative having 1 to 12 carbon atoms) A linear alkyl group having 1 to 12 carbon atoms, a linear alkyl ether having 1 to 12 carbon atoms, a linear alkyl ester having 1 to 12 carbon atoms, and a halogen atom, provided that L ¹ and When L ² is a derivative and all hydrogen atoms in the ring structure are substituted with methyl groups, except when both L ¹ and L ² are tetramethylcyclopentadienyl rings); M ¹ is a transition metal; X ^- low symmetry anion (low symmetry anion having a low symmetry anion or a cyano group having a fluorine atom is, molecules spherical symmetry, linear, tetrahedral, lifting shapes other than octahedron type It represents a a a) low symmetry anion. ] X ^- Bis (trifluoromethanesulfonyl) imide anion, bis (heptafluoropropanesulfonyl) imide anion, bis (nonafluorobutanesulfonyl) imide anion, cyclo-hexafluoropropane-1,3-bis (sulfonyl) imide, trifluoromethanesulfone The acid anion, nonafluorobutanesulfonic acid anion, trifluoroacetic acid anion, pentafluoropropionic acid anion, heptafluorobutyric acid anion, dicyanoamine anion, tricyanomethane anion is at least one kind selected from Claim 1 The metallocene ionic liquid described. The metallocene ionic liquid according to claim 1 or 2 , wherein the L ¹ and L ² are represented by the following general formula (2) or (3).
[Wherein R ^{1 to} R ⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an ether group having 1 to 12 carbon atoms, or an ester having 1 to 12 carbon atoms. Represents a group. ]
[Wherein R ^{6 to} R ¹¹ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an ether group having 1 to 12 carbon atoms, or an ester having 1 to 12 carbon atoms. Represents a group. ] Wherein M ¹ is selected from the group consisting of iron, cobalt, manganese, nickel, ruthenium, molybdenum, chromium, vanadium, claim 1-3 is at least one metal atom selected titanium, rhodium, iridium, from the group consisting of osmium, and rhenium Metallocene ionic liquid as described in any one of these . 2. The X ⁻ is at least one selected from the group consisting of a bis (trifluoromethanesulfonyl) imide anion, a bis (heptafluoropropanesulfonyl) imide anion, and a bis (nonafluorobutanesulfonyl) imide anion. metallocene-based ionic liquid according to any one of 1-4. A method for producing a metallocene ionic liquid represented by the following general formula (4),
A method for producing a metallocene ionic liquid, comprising reacting a metallocene derivative represented by the following general formula (5) with a silver salt represented by the following general formula (6).
[Wherein M ¹ is a transition metal; R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. ˜12 ether group or C 1-12 ester group (provided that when R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all hydrogen atoms, R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ are all In the case of a methyl group and R ²¹ and R ³¹ are hydrogen atoms and R ^{22 to} R ²⁵ and R ^{32 to} R ³⁵ are methyl groups); X ⁻ represents a low-symmetric anion or cyano having a fluorine atom It represents a low-symmetric anion having a group (a low-symmetric anion is a low-symmetry anion in which the molecule has a shape other than spherical symmetry, linear type, regular tetrahedral type, and regular octahedral type) . ]
[Wherein, M ¹ , R ^{21 to} R ²⁵ and R ^{31 to} R ³⁵ have the same meanings as those in the general formula (4)].
[Wherein, X ⁻ has the same meaning as the above general formula (4)] The method for producing a metallocene ionic liquid according to claim 6 , wherein the reaction is a solvent-free reaction.