JP7557813B2 - Metallocene Boron Polysubstituted Derivatives - Google Patents

Description

The present invention relates to metallocene boron polysubstituted derivatives.

Metallocenes such as ferrocene are organometallic compounds that have a cyclopentadienyl anion as a ligand, and are known for their use as catalysts. On the other hand, organoboron compounds are known as important synthetic intermediates in organic synthesis, and in recent years many of them have been synthesized as luminescent materials and are used in organic devices such as organic electroluminescent elements.

Regarding boronated metallocene compounds, Patent Document 1 discloses the use of boronated ferrocene compounds in fluoride or cyanide sensors.

As a method for producing a boronated ferrocene compound, Patent Document 1 discloses a method using n-BuLi. Furthermore, Patent Document 2 discloses a method using boron triiodide.

WO 2008/78092 JP 2019-43940 A

As an example of a boronated metallocene compound, a multi-boron substituted compound is disclosed in Patent Document 1. However, the method using n-BuLi described in Patent Document 1 is not practical because it requires reaction conditions at very low temperatures. In addition, Patent Document 2 shows an example of producing a mono-boron substituted ferrocene, but does not disclose an example of producing a multi-boron substituted compound.
An object of the present invention is to provide a novel poly-substituted metallocene boron derivative.

The present inventors conducted extensive research to solve the above problems, and obtained a novel compound, a metallocene boron polysubstituted derivative having a boron-containing substituent with two nitrogen atoms substituted on the boron, by a method including a process of reacting boron triiodide with a raw material metallocene. After further research, the inventors have completed the present invention. In other words, the present invention provides the following metallocene boron polysubstituted derivative and a method for producing a metallocene derivative using the same.

<1> A metallocene boron polysubstituted derivative,
having two or more boron-containing substituents bonded to any cyclopentadienyl ring at a boron;
At least one of the boron-containing substituents is a group represented by any one of the following formulas (a) to (e):

(In formulae (a) to (e), * indicates a bonding position, and R ¹ to R ⁸ each independently represent hydrogen, halogen, a hydroxyl group, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group.)

<2> The metallocene boron polysubstituted derivative according to <1>, wherein at least one of the boron-containing substituents is a group represented by formula (a).

<3> The metallocene boron polysubstituted derivative according to <2>, represented by formula (10):

In formula (10), M is Fe, Ni, Ru, Mn, Cr, Co, Os, or V;
^Y1 's each independently represent a hydrogen atom, -B(OH) ₂ , -B( ^ORa ) ₂ , a group represented by any one of formulas (a) to (q), a boron fluoride group, or _-BI2 ;
However, at least ^one Y is a group other than hydrogen;
R ^a is hydrogen or alkyl having 1 to 30 carbon atoms, any -CH ₂ - in the alkyl may be substituted with -O-, -S-, -CO-, >N-R or -SiH ₂ -, any -CH ₂ CH ₂ - may be substituted with -CH═CH- or -C≡C-, R of the >N-R is aryl which may be substituted with alkyl or halogen, heteroaryl which may be substituted with alkyl or halogen, or alkyl which may be substituted with halogen, and at least one hydrogen in R ^a may be substituted with halogen,
In formulae (a) to (q), * indicates a bonding position, and R ¹ to R ⁸ each independently represent hydrogen, halogen, a hydroxyl group, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group.

<4> At least one boron-containing substituent other than the group represented by any one of formulas (a) to (e) is selected from the group consisting of -B(OH) ₂ , -B( ^ORa ) ₂ , a group represented by any one of formulas (f) to (q), a boron fluoride group, and -BI2 _;
R ^a is hydrogen or alkyl having 1 to 30 carbon atoms, any -CH ₂ - in the alkyl may be substituted with -O-, -S-, -CO-, >N-R or -SiH ₂ -, any -CH ₂ CH ₂ - may be substituted with -CH═CH- or -C≡C-, R of the >N-R is aryl which may be substituted with alkyl or halogen, heteroaryl which may be substituted with alkyl or halogen, or alkyl which may be substituted with halogen, and at least one hydrogen in R ^a may be substituted with halogen,
In the formulas (f) to (q), * indicates a bonding position, and R ¹ to R ⁸ each independently represent hydrogen, halogen, a hydroxyl group, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group. The metallocene boron poly-substituted derivative according to any one of <1> to <3>.

<5> The metallocene boron poly-substituted derivative according to <4>, which contains at least one boron-containing substituent selected from the group consisting of -B(OH) ₂ , a group represented by formula (n), a boron fluoride group, and _-BI2, as a boron-containing substituent other than the group represented by any one of formulas (a) to (e).
<6> R ^a is alkyl having 1 to 9 carbon atoms,
The metallocene boron poly-substituted derivative according to any one of <1> to <5>, wherein R ¹ to R ⁸ are each independently hydrogen, alkyl having 1 to 9 carbon atoms, alkoxy having 1 to 9 carbon atoms, alkenyl having 2 to 8 carbon atoms, phenyl, naphthyl, anthracenyl, pyrenyl, triphenylenyl, chrysenyl, perylenyl, carbazolyl, dibenzofuranyl, or dibenzothiophenyl.
<7> The polysubstituted metallocene boron derivative according to <6>, wherein R ¹ to R ⁸ are each independently hydrogen or alkyl having 1 to 9 carbon atoms.
<8> An organic device comprising the poly-substituted metallocene boron derivative according to any one of <1> to <7>.
<9> A method for producing a poly-substituted metallocene derivative having two or more types of substituents bonded to any of the cyclopentadienyl rings, comprising using the poly-substituted metallocene boron derivative according to <4> or <5> as a production intermediate.

The present invention provides a novel metallocene boron polysubstituted derivative. The metallocene boron polysubstituted derivative of the present invention can be used as a synthetic intermediate for the production of various metallocene polysubstituted derivatives. The metallocene boron polysubstituted derivative of the present invention is also expected to be used as a light-emitting material or charge transport material for organic devices such as organic electroluminescent devices.

The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits. In this specification, "hydrogen" in the explanation of the structural formula means "hydrogen atom (H)".

In this specification, chemical structures and substituents are sometimes expressed by the number of carbon atoms, but when a chemical structure is substituted with a substituent or when a substituent is further substituted with a substituent, the number of carbon atoms means the number of carbon atoms in each of the chemical structure and the substituent, and does not mean the total number of carbon atoms in the chemical structure and the substituent, or the total number of carbon atoms in the substituent and the substituent. For example, "substituent B of carbon number Y substituted with substituent A of carbon number X" means that "substituent B of carbon number Y" is substituted with "substituent A of carbon number X", and the carbon number Y is not the total number of carbon atoms in the substituents A and B. Also, for example, "substituent B of carbon number Y substituted with substituent A" means that "substituent B of carbon number Y" is substituted with "substituent A (with no carbon number limit)", and the carbon number Y is not the total number of carbon atoms in the substituents A and B.

1. Metallocene boron polysubstituted derivatives Metallocenes are organometallic compounds having two cyclopentadienyl anions as ligands, and in the present invention, the metal in the metallocene is preferably a two-coordinate metal. A compound in which the metal in the metallocene is Fe is ferrocene. A metallocene boron polysubstituted derivative is a metallocene derivative in which at least two boron-containing substituents are substituted on the metallocene, and a metallocene boron tetrasubstituted derivative is a metallocene derivative in which four boron-containing substituents are substituted on the metallocene. The boron-containing substituents are bonded to the cyclopentadienyl ring via boron. When two boron-containing substituents are substituted on the cyclopentadienyl ring, the substitution positions of the boron-containing substituents are preferably the 1st and 3rd positions of each of the two cyclopentadienyl rings. That is, when the metallocene boron polysubstituted derivative is a metallocene boron tetrasubstituted derivative, it is preferably a 1,1',3,3'-substituted product. In addition, when the metallocene boron polysubstituted derivative has two boron-containing substituents, the two boron-containing substituents may be bonded to the same cyclopentadienyl ring or different cyclopentadienyl rings, but are preferably bonded to different cyclopentadienyl rings.

The stereostructure of the polysubstituted metallocene boron derivatives varies depending on the type and number of boron-containing substituents, and is not particularly limited.
Metallocene boron polysubstituted derivatives may exist as enantiomers or diastereomers depending on the number and type of boron-containing substituents. Regardless of the structural formula shown, any stereoisomer in any pure form, any mixture of stereoisomers, racemates, etc. are all intended to be included within the scope of the present invention.

The metallocene boron polysubstituted derivative of the present invention has two or more boron-containing substituents bonded to any of the cyclopentadienyl rings at boron, and at least one of the boron-containing substituents is a group represented by any of formulas (a) to (e). The metallocene boron polysubstituted derivative of the present invention has two or more boron-containing substituents, preferably 2 to 6, and more preferably 2 to 4. The metallocene boron polysubstituted derivative of the present invention has one or more groups represented by any of formulas (a) to (e), preferably 1 to 4, and more preferably 1 to 3. Of the groups represented by any of formulas (a) to (e), the group represented by formula (a) is particularly preferred.
The polysubstituted metallocene boron derivatives of the present invention may have substituents other than the boron-containing substituents.

The metallocene boron polysubstituted derivative of the present invention preferably contains at least one other boron-containing substituent selected from the group consisting of -B(OH) ₂ , -B(OR ^a ) ₂ , a group represented by any of formulas (f) to (q), a boron fluoride group, and -BI ₂ as a boron-containing substituent other than the group represented by any of formulas (a) to (e). This is because it has a structure that simultaneously has a substituent that can be converted to another substituent by a coupling reaction and a substituent that cannot be converted, and is particularly useful as a manufacturing intermediate for the production of various metallocene polysubstituted derivatives. For example, the above boron-containing substituents such as -B(OH) ₂ can be converted to various substituents by a coupling reaction, but the group represented by any of formulas (a) to (e) cannot be converted by a coupling reaction. By utilizing this, only the boron-containing substituent that can be subjected to a coupling reaction is converted first, and then the group represented by any of formulas (a) to (e) is converted to -B(OH) ₂ or the like, so that another substituent can be introduced by a coupling reaction. That is, starting from a metallocene boron polysubstituted derivative having a group represented by any one of formulas (a) to (e) and the above-mentioned other boron-containing substituent, a metallocene polysubstituted derivative in which a different substituent is introduced at a position can be obtained.

In the above definitions, R ^a is hydrogen or alkyl having 1 to 30 carbon atoms, any -CH ₂ - in the alkyl may be substituted with -O-, -S-, -CO-, >N-R or -SiH ₂ -, any -CH ₂ CH ₂ - may be substituted with -CH=CH- or -C≡C-, R in the >N-R is aryl which may be substituted with alkyl or halogen, heteroaryl which may be substituted with alkyl or halogen, or alkyl which may be substituted with halogen, and at least one hydrogen in R ^a may be substituted with halogen.
Moreover, the formulas (a) to (q) are as follows.

In formulae (a) to (q), * indicates a bonding position, and R ¹ to R ⁸ each independently represent hydrogen, halogen, a hydroxyl group, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group.

In R ^a and R ¹ to R ⁸ , "alkyl" may be either linear or branched, and examples thereof include linear alkyl having 1 to 24 carbon atoms or branched alkyl having 3 to 24 carbon atoms. An alkyl having 1 to 18 carbon atoms (branched alkyl having 3 to 18 carbon atoms) is preferred, an alkyl having 1 to 9 carbon atoms (branched alkyl having 3 to 9 carbon atoms) is more preferred, an alkyl having 1 to 6 carbon atoms (branched alkyl having 3 to 6 carbon atoms) is even more preferred, and an alkyl having 1 to 4 carbon atoms (branched alkyl having 3 to 4 carbon atoms) is particularly preferred.

Specific examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, 2 -Ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, 3,5,5-trimethylhexyl, n-decyl, n-undecyl, 1-methyldecyl, n-dodecyl, n-tridecyl, 1-hexylheptyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-eicosyl, etc.

In R ¹ to R ⁸ , "alkenyl" may be either linear or branched, and examples thereof include linear alkenyl having 2 to 24 carbon atoms or branched alkenyl having 3 to 24 carbon atoms. Alkenyl having 2 to 18 carbon atoms (branched alkenyl having 3 to 18 carbon atoms) is preferred, alkenyl having 2 to 9 carbon atoms (branched alkenyl having 3 to 9 carbon atoms) is more preferred, alkenyl having 2 to 6 carbon atoms (branched alkenyl having 3 to 6 carbon atoms) is even more preferred, and alkenyl having 2 to 4 carbon atoms (branched alkenyl having 3 to 4 carbon atoms) is particularly preferred.

Specific examples of "alkenyl" include vinyl, allyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, 3-methyl-1-butenyl, 2-methyl-1-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-methyl-1-pentenyl, 2-methyl-1 -pentenyl, 3-methyl-1-pentenyl, 4-methyl-1-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-heptenyl, 2-heptenyl, 3-heptenyl, 4-heptenyl, 5-heptenyl, 6-heptenyl, 1-octenyl, 2-octenyl, 3-octenyl, 4-octenyl, 5-octenyl, 6-octenyl, 7-octenyl, etc. Among these, vinyl and allyl are preferred.

In R ¹ to R ⁸ , examples of "alkoxy" include linear alkoxy having 1 to 24 carbon atoms or branched alkoxy having 3 to 24 carbon atoms. An alkoxy having 1 to 18 carbon atoms (branched alkoxy having 3 to 18 carbon atoms) is preferred, an alkoxy having 1 to 9 carbon atoms (branched alkoxy having 3 to 9 carbon atoms) is more preferred, an alkoxy having 1 to 6 carbon atoms (branched alkoxy having 3 to 6 carbon atoms) is even more preferred, and an alkoxy having 1 to 4 carbon atoms (branched alkoxy having 3 to 4 carbon atoms) is particularly preferred.

Specific examples of "alkoxy" include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, s-butoxy, t-butoxy, pentyloxy, hexyloxy, heptyloxy, and octyloxy.

In R ¹ to R ⁸ , "halogen" includes fluorine, chlorine, bromine and iodine.

In R ¹ to R ⁸ , specific examples of "aryl" include a monocyclic ring system such as phenyl, a bicyclic ring system such as biphenylyl, a fused bicyclic ring system such as naphthyl (1-naphthyl or 2-naphthyl), a tricyclic ring system such as terphenylyl (m-terphenylyl, o-terphenylyl or p-terphenylyl), a fused tricyclic ring system such as acenaphthylenyl, fluorenyl, phenalenyl, phenanthrenyl, a fused tetracyclic ring system such as triphenylenyl, pyrenyl, naphthacenyl, a fused pentacyclic ring system such as perylenyl, pentacenyl, etc.

In R ¹ to R ⁸ , examples of "heteroaryl" include pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl, isoquinolinyl, cinnoline, and phenyl. nyl, quinazolinyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiinyl, phenoxazinyl, phenothiazinyl, phenazinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thiophenyl, benzothiophenyl, isobenzothiophenyl, dibenzothiophenyl, naphthobenzothiophenyl, furazanyl, thianthrenyl, and the like.

In formulas (a) to (q), R ¹ to R ⁸ are preferably each independently hydrogen, alkyl having 1 to 9 carbon atoms, alkoxy having 1 to 9 carbon atoms, alkenyl having 2 to 8 carbon atoms, phenyl, naphthyl, anthracenyl, pyrenyl, triphenylenyl, chrysenyl, perylenyl, carbazolyl, dibenzofuranyl, or dibenzothiophenyl. It is more preferable that ^{R 1} to R ⁸ are each independently hydrogen or alkyl having 1 to 9 carbon atoms. In formula (a), it is more preferable that R ¹ to R ⁸ are all hydrogen. In formula (e), it is more preferable that R ¹ to R ⁴ are all hydrogen, and R ⁵ and R ⁶ are all hydrogen, or one of them is hydrogen and the other is methyl. In formula (n), it is more preferable that R ¹ to R ⁴ are all methyl.

R ^a in --B(OR ^a ) ₂ is preferably an alkyl group having 1 to 9 carbon atoms.
The boron fluoride group includes groups in which --BF ₃ ^-- forms a salt. For example, --BF ₃ Li, --BF ₃ Na and --BF ₃ K are preferred, with BF ₃ K being more preferred.
The formula (m) may be in the form of a salt, and examples of such salts include Li salts, Na salts and K salts, with K salts being preferred.

As described above, the metallocene boron polysubstituted derivative of the present invention preferably has at least one group represented by formula (a), and is preferably, for example, a metallocene boron polysubstituted derivative represented by formula (10).

In formula (10), M is Fe, Ni, Ru, Mn, Cr, Co, Os, or V;
Each ^Y1 is independently hydrogen, -B(OH) ₂ , -B( ^ORa ) ₂ , a group represented by any one of the above formulas (a) to (q), a boron fluoride group, or _-BI2 , and the definitions and preferred ranges of ^Ra , ^R1 to ^R8 are the same as those described above.
In formula (10), at least one Y ¹ is a group other than hydrogen. In formula (10), it is preferred that at least one of the two Y ^{1 s} bonded to the upper cyclopentadienyl ring is a group other than hydrogen.

Specific examples of the metallocene boron polysubstituted derivatives of the present invention include the following compounds. Note that the following structure is just one example.

More specific examples include the following compounds:

2. Method for Producing Poly-Substituted Metallocene Boron Derivatives The poly-substituted metallocene boron derivatives of the present invention may be produced by any known method, but are preferably produced by a method including a step of reacting a metallocene compound with boron triiodide. A boron diiodide-substituted metallocene can be obtained by reacting a metallocene compound with boron triiodide. Furthermore, a reaction is carried out in which at least one of -BI ₂ in this boron diiodide-substituted metallocene is replaced with -B(OH) ₂ , -B(OR ^a ) ₂ , a group represented by any one of formulas (f) to (q), or a boron fluoride group. Then, a reaction is carried out in which at least one of the substituted groups is converted into a group represented by any one of formulas (a) to (e), thereby obtaining the poly-substituted metallocene boron derivatives of the present invention.

2-1. Boron diiodide-substituted metallocene As described above, a boron diiodide-substituted metallocene can be obtained by reacting a metallocene compound with boron triiodide. Here, it is preferable that the metallocene compound as the starting material is not substituted with a boron-containing substituent.
For example, a boron diiodide tetra-substituted metallocene can be obtained by reacting a metallocene compound with greater than four molar equivalents of boron triiodide.

The amount of boron triiodide added may be adjusted depending on the number of boron-containing substituents in the metallocene boron polysubstituted derivative to be produced. For example, when producing a metallocene boron polysubstituted derivative having four boron-containing substituents, the amount is preferably more than 5 molar equivalents of tetrasubstituted metallocene boron diiodide, more preferably more than 8 molar equivalents, and even more preferably more than 10 molar equivalents. The upper limit is preferably about 50 molar equivalents or less, and more preferably about 20 molar equivalents or less.

In the above production method, a Lewis acid may be added to promote the reaction. Preferred Lewis acids include boron trifluoride diethyl ether complex, boron trichloride, boron tribromide, aluminum chloride, aluminum bromide, silver trifluoromethanesulfonate (I), iron chloride (III), and iron bromide (III).

The reaction solvent used in the above production method may be any solvent that does not inhibit the reaction itself, and may be selected from common solvents such as hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane, and halogenated aromatic hydrocarbons such as chlorobenzene, 1,2-dichlorobenzene, 2,4-dichlorotoluene, and 1,2,4-trichlorobenzene, either alone or in combination. It is also possible to carry out the reaction using only the reaction substrates without using a reaction solvent.

The above production method is desirably carried out at an appropriate reaction temperature. That is, it is preferable to carry out the method at a temperature between -78°C and the boiling point of the reaction substrate or solvent used in order to simplify the operation. Considering the balance between the reaction rate and the amount of by-products produced, it is more preferable to carry out the method at a temperature between 20°C and 250°C. The above production method can be carried out in air, but is preferably carried out in an inert gas atmosphere such as nitrogen or argon.

2-2. Reaction of boron diiodide-substituted metallocene By reacting the boron diiodide-substituted metallocene obtained as above with water, alcohol, diol (R ^a -OH), dicarboxylic acid (OH-R ¹⁰ -OH), or alkali metal fluoride (LiF, NaF, KF, etc.), a further intermediate for the production of the metallocene boron polysubstituted derivative of the present invention can be obtained. For example, by reacting the boron diiodide tetrasubstituted metallocene (Y) with water, alcohol (R ^a -OH), or diol or dicarboxylic acid (OH-R ¹⁰ -OH), a boronic acid compound represented by the following formula (1-1), a boronic acid ester compound (1-2), or a boronic acid ester compound represented by the following formula (1-4) can be produced, respectively. The substituents of these compounds can be further converted to groups represented by any one of formulas (a) to (e) as described below, to obtain the metallocene boron polysubstituted derivative of the present invention. The symbols in each formula are as defined above.

R ^a in the water or alcohol "R ^a -OH" used in the reaction has the same meaning as R ^a above.

Specific examples of alcohols that can be used include methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, 1-butanol, 2-butanol, cyclobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 1-pentanol, 2-ethyl-2-propanol, 1-hexanol, 2-hexanol, 4-methyl-2-pentanol, 3,3-dimethyl-1-butanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 1-octanol, 1,1,3,3-tetramethyl-1-butanol, Examples of such alcohols include ethanol, 2-octanol, 2-ethyl-1-hexanol, 2-propyl-1-pentanol, 1-nonanol, 2,2-dimethyl-1-heptanol, 2,6-dimethyl-4-heptanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, 1-undecanol, 2-undecanol, 1-dodecanol, 1-tridecanol, 6-tridecanol, 1-tetradecanol, 1-heptadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, and 1-eicosanol.

R ¹⁰ in the diol "OH-R ¹⁰ -OH" used in the reaction is an alkylene having 1 to 30 carbon atoms or an arylene having 6 to 16 carbon atoms, in which any -CH ₂ - in the alkylene may be substituted with -O-, -S-, -CO-, >N-R or -SiH ₂ -, any -CH ₂ CH ₂ - may be substituted with -CH═CH- or -C≡C-, at least one hydrogen may be substituted with a halogen, and at least one hydrogen in the arylene may be substituted with an alkyl having 1 to 10 carbon atoms or a halogen. Here, R in the >N-R is an aryl which may be substituted with an alkyl or a halogen, a heteroaryl which may be substituted with an alkyl or a halogen, or an alkyl which may be substituted with an alkyl or a halogen.

Examples of the alkylene having 1 to 30 carbon atoms include the divalent groups of "alkyl having 1 to 30 carbon atoms" explained above as R ^a .

Specific examples of arylenes having 6 to 16 carbon atoms include 1,2-phenylene, 1,4-phenylene, 1,2-naphthylene, 2,3-naphthylene, and 4,5-naphthylene.

Specific examples of diols that can be used include ethylene glycol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,2-cyclohexanediol, benzopinacol, pinacol, 1-(1-hydroxycyclohexyl)-cyclohexane-1-ol, 1-(4-methoxyphenyl)-cyclohexane-1-ol, and 1-(1-hydroxyphenyl)-cyclohexane-1-ol. Examples of dicarboxylic acids that can be used include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, malic acid, itaconic acid, fumaric acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid, and N-methyliminodiacetic acid.

In the esterification, a Bronsted base such as triethylamine, N,N-diisopropylethylamine, tetramethylpiperidine, pentamethylpiperidine, or N,N-dimethyl-p-toluidine may be added for the purpose of promoting the reaction, or the alcohol "R ^a -OH" or the diol or dicarboxylic acid "OH-R ¹⁰ -OH" may be converted into a metal salt in advance and then used.

The reaction solvent used in the above production method may be any solvent that does not inhibit the reaction itself, and may be selected from, for example, common organic solvents such as hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane, halogenated aromatic hydrocarbons such as chlorobenzene, 1,2-dichlorobenzene, 2,4-dichlorotoluene, and 1,2,4-trichlorobenzene, as well as diethyl ether, tetrahydrofuran, dichloromethane, chloroform, ethyl acetate, benzene, toluene, and acetonitrile, either alone or in combination. It is also possible to carry out the reaction using only the reaction substrate without using a reaction solvent.

The above production method is desirably carried out at an appropriate reaction temperature. That is, it is preferable to carry out the method at a temperature between -78°C and the boiling point of the solvent used in order to simplify the operation. Considering the balance between the reaction rate and the amount of by-products produced, it is more preferable to carry out the method at a temperature between 0°C and 100°C. The above production method can be carried out in the air, but is preferably carried out in an inert gas atmosphere such as nitrogen or argon.

The desired boric acid ester can be obtained by reacting a monohydric alcohol with a boron diiodide-substituted metallocene. For example, when the boron diiodide-substituted metallocene is a boron diiodide tetra-substituted metallocene, the amount of monohydric alcohol to be reacted may be more than 8 molar equivalents, more preferably more than 10 molar equivalents, and even more preferably more than 15 molar equivalents. The upper limit is preferably about 100 molar equivalents or less, and more preferably about 50 molar equivalents or less.

The desired boric acid ester can be obtained by reacting a dihydric alcohol or a divalent carboxylic acid with a boron diiodide-substituted metallocene. For example, when the boron diiodide-substituted metallocene is a boron diiodide tetra-substituted metallocene, the amount of dihydric alcohol or divalent carboxylic acid to be reacted may be more than 4 molar equivalents, more preferably more than 8 molar equivalents, and even more preferably more than 10 molar equivalents. The upper limit is preferably about 50 molar equivalents or less, and more preferably about 20 molar equivalents or less.

In the above production method, the product can be isolated from the reaction system after completion of the reaction by a method used in normal chemical operations. For example, the reaction can be stopped by adding water to the reaction solution, and then extracted from the reaction system with an organic solvent. If necessary, the reaction product can be purified by recrystallization, distillation, silica gel chromatography, or other purification procedures, either alone or in combination, to produce a boronic acid or boronic acid ester with a higher purity. Alternatively, the reaction product can be converted to a compound that is easier to purify by converting the functional group without purifying it, and then the desired compound can be obtained by performing the above-mentioned purification procedures, either alone or in combination.

More specific examples of the boronic acid ester compound represented by formula (1-4) include compounds represented by the following formulae (1-n), (1-p), (1-p), and (1-q), which have formulae (n) to (q) as boron-containing substituents and are obtained by reacting the following diols (n') to (q') with (Y).

2-3. Method using boronic acid compound (1-1) The boronic acid compound represented by formula (1-1) can be converted to a compound more stable against acids and oxidizing agents. For example, by reacting it with a diamine, a dicarboxylic acid, a carboxylic acid, potassium hydrogen fluoride, or the like, it is possible to obtain a compound in which the boron-containing substituent is -BF ₃ K or a group represented by formula (a) to formula (l). These compounds can be used as starting materials for producing various compounds. As examples, compounds (1-3), (1-a), and (1-l) having -BF ₃ K, formula (a), and formula (l) as the boron-containing substituent are listed below. Note that metallocene boron polysubstituted derivatives having other boron fluoride groups (-BF ₃ Li, -BF ₃ Na) instead of -BF ₃ K can also be produced in the same manner.

The metallocene boron polysubstituted derivative of the present invention can be obtained by further converting the boronic acid compound (1-1) or the above compound (1-n) into a group represented by any one of formulas (a) to (e). An example of reacting compound (1-n) with an equal amount of diaminonaphthalene (a') to convert it into compound (1-a-1) is shown below.

2-4. Other Production Intermediates Examples of tetra-substituted metallocene boron derivatives that can be used as production intermediates for the poly-substituted metallocene boron derivatives of the present invention are given below.

More specific examples include the following compounds:

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these.

Synthesis Example (1): Synthesis of 1,1',3,3'-tetrakis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ferrocene (ferrocene-1,1',3,3'-(Bpin) ₄ ) (Compound No. 4)

Under a nitrogen atmosphere, a Schlenk containing ferrocene (37.2 mg, 0.20 mmol), boron triiodide (940 mg, 2.4 mmol) and 1,2,4-trichlorobenzene (2.0 ml) was heated to 150°C and stirred for 16 hours. The reaction solution was cooled to room temperature and hydrogen iodide was removed under reduced pressure. The reaction solution was cooled to 0°C and triethylamine (4.00 ml, 29 mmol) and pinacol (851 mg, 7.2 mmol) were added using a cannula. After stirring at room temperature for 30 minutes, the solvent was removed under reduced pressure to obtain the crude product. The resulting crude product was washed with hexane and purified by GPC (eluent: 1,2-dichloroethane) to obtain 1,1',3,3'-tetrakis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ferrocene (compound No. 4, 42.8 mg, yield 31%) as a brown solid.

The structure of the obtained compound No. 4 was confirmed by NMR measurement.
^1H -NMR (400MHz, CDCl ₃ ): δ = 1.34-1.35 (m, 48H), 4.53 (d, 4H), 4.59 (s, 2H)
^13C -NMR (101MHz, CDCl ₃ ): 25.0 (8C + 8C), 77.3 (4C), 81.1 (2C), 83.1 (8C)

Synthesis Example (2): Synthesis of 1,1',3-tris(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3'-(2,3-dihydro-1H-naphtho[1,8-d,e][1,3,2]diazaborinyl)ferrocene (ferrocene-1,1',3-(Bpin) ₃ -3'-Bdan) (Compound No. 50)

Under a nitrogen atmosphere, a 30 ml two-neck flask containing 1,1',3,3'-tetrakis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ferrocene (0.103 g, 0.15 mmol), 1,8-diaminonaphthalene (23.7 mg, 0.15 mmol), n-butanol (2.0 ml) and mesitylene (8.0 ml) was heated to 140°C and stirred for 60 hours. The reaction solution was cooled to room temperature and the solvent was removed under reduced pressure to obtain a crude product. The resulting crude product was purified by GPC (eluent: 1,2-dichloroethane) and silica gel column chromatography (eluent: hexane/ethyl acetate = 7/1) to obtain 1,1',3-tris(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3'-(2,3-dihydro-1H-naphtho[1,8-d,e][1,3,2]diazaborinyl)ferrocene (compound No. 50, 20.8 mg, yield 19%) as an orange solid.

The structure of the obtained compound No. 50 was confirmed by NMR measurement.
^1H -NMR (400MHz, CDCl ₃ ): δ = 1.36-1.38 (m, 24H), 1.41-1.43 (m, 12H), 4.42 (s, 1H), 4.50-4.56 (m, 5H), 6.40 (d, 2H), 6.48 (s, 2H), 7.02 (d, 2H), 7.13 (t, 2H)
^13C -NMR (101MHz, CDCl ₃ ): 25.0-25.1 (4C + 4C), 25.2 (2C + 2C), 75.5 (1C), 76.9 (1C), 77.5 (1C), 78.9 (1C), 80.0 (1C), 82.7 (1C), 83.3-83.6 ( 4C+1C+1C), 105.3 (2C), 117.0 (2C), 120.0 (1C), 127.5 (2C), 136.5 (1C), 141.9 (2C).
(The NMR signal of the carbon atom located α to the boron atom is not observed.)

Synthesis Example (3): Synthesis of 1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1'-(2,3-dihydro-1H-naphtho[1,8-d,e][1,3,2]diazaborinyl)ferrocene (ferrocene-1-Bpin-1'-Bdan, Compound No. 74 in which M is Fe)

Under a nitrogen atmosphere, an autoclave containing 1,1'-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ferrocene (compound No. 74 where M is Fe, 87.6 mg, 0.20 mmol), 1,8-diaminonaphthalene (47.5 mg, 0.30 mmol), n-butanol (3.0 ml) and mesitylene (12 ml) was heated to 250°C and stirred for 4 hours. The reaction solution was cooled to room temperature and the solvent was distilled off under reduced pressure to obtain a crude product. The resulting crude product was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 7/1) and washing with hexane to obtain 1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1'-(2,3-dihydro-1H-naphtho[1,8-d,e][1,3,2]diazaborinyl)ferrocene (29.6 mg, yield 31%) as an orange solid.

The structure of the obtained compound was confirmed by NMR measurement.
^1H -NMR (400MHz, CDCl ₃ ): δ = 1.45 (s, 12H), 4.28 (t, 2H), 4.35 (t, 2H), 4.38-4.39 (m, 4H), 6.26 (s, 2H), 6.42 (d, 2H), 7.03 (d, 2H), 7.14 (t, 2H)
^13C -NMR (101MHz, CDCl ₃ ): 25.1 (4C), 71.2 (2C), 72.3 (2C), 72.4 (2C), 75.2 (2C), 83.6 (2C), 105.4 (2C), 117.2 (2C), 119.7 (1C), 127.6 (2C), 1 36.4 (1C), 141.6 (2C).
(The NMR signal of the carbon atom located α to the boron atom is not observed.)

The present invention provides a novel metallocene boron polysubstituted derivative. The metallocene boron polysubstituted derivative of the present invention is expected to be used as a light-emitting material, charge transport material, and semiconductor material for organic devices such as organic electroluminescent devices, organic field effect transistors, and organic thin-film solar cells, and is also expected to be used as a positive electrode material or a negative electrode material for secondary batteries. It is also expected to be used as a synthetic intermediate for such materials, and application to new materials is expected through stepwise coupling with conjugated compounds. Furthermore, by introducing phosphorus or nitrogen, it is expected to be used as a ligand for transition metal catalysts.

Claims (9)

A metallocene boron poly-substituted derivative having two or more boron-containing substituents bonded to any of the cyclopentadienyl rings at boron ,
At least one of the boron-containing substituents is a group represented by any one of the following formulas (a) to (e):
The compound contains at least one boron-containing substituent other than the group represented by any one of formulas (a) to (e) selected from the group consisting of -B (OH) ₂ , -B(ORa ⁾ 2 _, a group represented by any one of formulas (f) to (q), a boron fluoride group, and -BI2 _;
R ^a is an alkyl group having 1 to 9 carbon atoms;
In formulae (a) to (q), * indicates a bonding position, and R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group.
Metallocene boron polysubstituted derivatives.

The metallocene boron polysubstituted derivative according to claim 1, wherein at least one of the boron-containing substituents is a group represented by formula (a). The metallocene boron polysubstituted derivative according to claim 2, represented by formula (10):

In formula (10), M is Fe, Ni, Ru, Mn, Cr, Co, Os, or V;
^Y1 's each independently represent a hydrogen atom, -B(OH) ₂ , -B( ^ORa ) ₂ , a group represented by any one of formulas (a) to (q), a boron fluoride group, or _-BI2 ;
However, at least one Y ¹ is --B(OH) ₂ , --B(OR ^a ) ₂ , a group represented by any one of formulas (f) to (q), a boron fluoride group, or --BI ₂ . The metallocene boron poly-substituted derivative according to any one of claims ₁ to 3, which contains at least one boron-containing substituent other than the group represented by any one of formulas (a) to (e) selected from the group consisting of -B(OH) ₂ , a group represented by formula (n), a boron fluoride group, and -BI2. The metallocene boron polysubstituted derivative according to any one of claims 1 to 4, wherein R ¹ to R ⁸ are each independently hydrogen, alkyl having 1 to 9 carbon atoms, alkoxy having 1 to 9 carbon atoms, alkenyl having 2 to 8 carbon atoms, phenyl, naphthyl, anthracenyl, pyrenyl, triphenylenyl, chrysenyl, perylenyl, carbazolyl, dibenzofuranyl, or dibenzothiophenyl. 6. The metallocene boron polysubstituted derivative according to claim 5 , wherein R ¹ to R ⁸ are each independently hydrogen or alkyl having 1 to 9 carbon atoms. Contains a group represented by formula (n), in which R ¹ ~R ⁴ The metallocene boron polysubstituted derivative according to any one of claims 1 to 6, wherein each of is methyl. The metallocene boron polysubstituted derivative according to any one of claims 1 to 7, wherein the metal in the metallocene is Fe. A metallocene boron polysubstituted derivative represented by any one of the following formulas: