JP2002037615A - Metal-including fullerene ion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an unstable characteristic which a metal-including fullerene posseses and also to provide a metal-including fullerene material having a new characteristic. SOLUTION: The metal-including fullerene formed by electrolysis has an electronic structure of a closed shell and is represented by the general formula M Cn (M=Sc, Y, La, Lanthanide element, Actinoid element, n = an even number of 60, 70>=).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an anionic species and a cationic species formed by electrolytically reducing or oxidizing a metal-encapsulated fullerene. The metal-encapsulated fullerene anion and cation of the present invention have a closed-shell electronic structure, have an electronic structure similar to ordinary empty fullerene, and can cause conversion of various molecules by being ionic. . Further, after the chemical modification, it can be converted to a metal-encapsulated fullerene having a closed shell structure, and such a molecular conversion allows the metal-encapsulated fullerene to be widely applied. Utilizing the cation and anion properties of this new metal-encapsulated fullerene, functional materials such as electric and electronic materials with improved conductivity
It can be expected to be used as a catalyst due to an increase in reactivity, or to be converted into a modified metal-encapsulated fullerene to form a derivative such as a drug.

[0002]

2. Description of the Related Art The progress of fullerene science has been remarkable, and the creation of new fullerenes other than empty fullerenes has attracted attention. A metal-encapsulated fullerene having a metal atom encapsulated in the internal cavity of an empty fullerene has new electronic properties with the electron transfer from the internal metal atom to the carbon cage. For example, a metal-encapsulated fullerene La ＠ C by R. Samalleyr et al.
Since the report of ₈₂ , M ＠ containing Sc, Y, La atoms, etc.
Metal-encapsulated fullerenes such as C ₈₂ (M = Sc, Y, La, etc.) have been actively studied. The present inventor reported, as the first reaction of metal-encapsulated fullerenes, a method for synthesizing an organosilicon derivative in which disilirane was added to a double bond of metal-encapsulated fullerenes (Nature 1995, 374, 600, J. Che.
m. Commu. 1995,1343). However, since these metal-encapsulated fullerenes are radical fullerenes having an open shell structure, they are unstable in air and are difficult to handle. These are major obstacles to material applications.

Under such circumstances, the present inventor previously described a relatively stable metal-containing azafullerene cation by FAB (Fast A).
stable generation using the tom bombardment method,
And a technique for utilizing such a stable cation molecular magnet (JP-A-2000-159513). As a result, application as a new material in the field of electronic materials and medical fields utilizing the new physical properties of the cation is expected. However, the technique for stably presenting the cation is under special conditions such as in FAB, and has a disadvantage that it cannot be handled under normal conditions such as normal temperature and normal pressure.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the unstable characteristics of the metal-encapsulated fullerene and to create a new metal-encapsulated fullerene material having new characteristics. The inventor of the present invention has found that the unstable structure of the metal-encapsulated fullerene has a radical (electron spin) on the carbon gauge and is based on an open shell structure. It is considered that the metal-encapsulated fullerene has a closed shell structure by giving or removing electrons to the metal-encapsulated fullerene, in other words, by reducing or oxidizing the metal-encapsulated fullerene, thereby improving the instability of the metal-encapsulated fullerene. I thought. Therefore, in examining a means for reducing or oxidizing the metal-encapsulated fullerene, it is possible to stably handle even under atmospheric pressure and in the presence of light by electrolytically oxidizing and reducing in a solution. The present inventors have found that the metal-encapsulated fullerene anion or cation can be present in a state, and also studied various properties of the stable ion to examine the possibility of the ion for various uses. Was solved.

[0005]

According to the present invention, there is provided a compound represented by the general formula M ＠ Cn wherein the electronic structure formed by the electrolytic method is a closed shell structure.
(However, M = Sc, Y, La, lanthanide element, actinoid element, n = 60, 70 and even more) and is a metal-encapsulated fullerene ion. Preferably, the metal-containing fullerene ion is characterized in that n is 82, and more preferably, the metal-containing fullerene ion is characterized in that M is La or Pr.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail.
A. La @ C₈₂And Pr ＠ C₈₂Metallic fuller etc.
There are also isomers. The inventor of this regard
(J, Phys. Chem., 1994, 98, 12831, Che
m.Phys.Lett., 2000, 319, 153). La and Pr @ C₈₂
In the case of C₈₂Have different structures (C₈₂Structural isomer)
Two isomers containing La or Pr atoms in the di
The main product (which is obtained in large quantities)
) And by-products (the amount obtained is smaller than the main product)
), Respectively La or PrＰC₈₂-A and
La or Pr @ C₈₂-B, or La or Pr
＠C₈₂-I and La or Pr @ C₈₂Named -II
Have been. Here, it is expressed according to the former naming.
You. Each isomer has an absorption spectrum (FIG. 1,
2), electron spin spectrum (Fig. 3), redock potential
Etc. in all properties (Figures 1 to 3 and Table 1
reference). Table 1 shows La ＠ C₈₂-A, La ＠ C₈₂-B, Pr
＠C₈₂-A and Pr @ C ₈₂Shows the oxidation-reduction potential of -B
You. In the table^OXE is the oxidation potential,^redE is the reduction potential
Represent.

[0007]

[Table 1]

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following embodiments, equipments and the like used will be described together. 1. UV-visible absorption spectrum: Perkin-Elmer Lambda 19
& Hewlett-Paccardmodel 8453 Spectrometer 2. Near infrared: Perkin-Elmer model 330 spectrometer ESR (Electron spin resonance): Bruker ER 1
00D (X band ESR spectrometer with variable temperature device 4. A normal CV measuring device is used as the three-electrode cell, and two Pt nets constituting the working electrode and the counter electrode are sintered glass for the voltage controlled bulk electrolysis. H-type cell separated by frit was used 5. Production of anions and cations of metal-encapsulated fullerene Anions and cations of metal-encapsulated fullerenes were redox vs. M ＠ C ₈₂ ^{(n + 1))} / M ＠ C, respectively. _A negative or positive voltage of 150 to 200 mV is applied from E _{1/2 of 82} ⁿ⁻ and M ＠ C ₈₂ ^{n +} / M ＠ C ₈₂ ^{(n−1) +} to dissolve 0.2 M of the electrolyte TBAP, and ODCB / TCB ( 3: 1) Produced in solution TBAP = (n-Bu) ₄ N (+) ClO ₄ (-) = tetra-n-butylammonium perchlorate ODCB = Cl ₂ C ₆ H ₄ = Orthodichlorobenzene, TCB = ClC ₆ H ₅ = chlorobenzene

Example 1 1 mg of the metal-encapsulated fullerene La @ C ₈₂ -A isomer was added to 0.1 mg.
2M tetrabutylammonium perchlorate (TBA
Dissolve in 8 mL of P) / orthodichlorobenzene (ODCB) solution, and perform argon bubbling for 20 minutes. Under the atmosphere,
Electrolysis was performed at 0 V to synthesize La @ C ₈₂ -A anion. The ultraviolet-visible-near-infrared absorption spectrum (FIG. 4) and the nuclear magnetic resonance spectrum of the anion were measured. ^{13 in} FIG.
3 shows a CNMR (125 MHz) spectrum. The spectrum consists of seventeen peaks of approximately equal intensity and seven peaks, approximately half the intensity of said peak. 24 total NMR
Signals appear in the chemical shift range of 135～158Ppm, which is a little wider than the chemical shift range of the air-C ₈₂ (131~151ppm). No change was observed in the UV-visible near-infrared absorption spectrum after the solution of the La @ C ₈₂ -A anion was allowed to stand in air for 4 months.

Example 2 1 mg of the metal-encapsulated fullerene La @ C ₈₂ -A isomer was added to 0.1 mg.
After dissolving in 8 mL of 2M TBAP / ODCB solution and performing argon bubbling for 20 minutes, under an argon atmosphere in an H-type cell in which three kinds of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE) are set) + 0.8 V at perform electrolysis, La @ C ₈₂ a -A cation were synthesized. measure of .la @ C ₈₂ -A cation been of ultraviolet-visible-near infrared absorption spectrum of the cation (FIG. 4b) solution, No change was observed in the ultraviolet-visible near-infrared absorption spectrum after standing for one week in air: La {C ₈₂ , La}.
FIG. 4 shows UV-visible-near-infrared absorption spectra of C ₈₂ (−) and La ＠ C ₈₂ (+). FIG. 6 (DPV = differential puls vol.) Shows the potential characteristic of anion and cation formation of La @ C ₈₂ -A (SCE = reference calomel electrode).
tammetry).

Example 3 1 mg of the metal-encapsulated fullerene La @ C ₈₂ -B isomer was added in 0.1 mg.
After dissolving in 8 mL of 2M TBAP / ODCB solution and performing argon bubbling for 20 minutes, under an argon atmosphere in an H-type cell in which three kinds of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE) are set) Electrolysis was performed at 0 V to synthesize an anion of LaＬC ₈₂ -B.The ultraviolet-visible-near-infrared absorption spectrum of the anion (FIG. 7A) and the nuclear magnetic resonance spectrum (FIG. 8) were measured. ＠C ₈₂ −
No change was observed in the ultraviolet-visible-near infrared absorption spectrum after the solution of the anion B was allowed to stand in the air for one week.

Example 4 1 mg of the metal-encapsulated fullerene La @ C ₈₂ -B isomer was added to 0.1 mg.
After dissolving in 8 mL of 2M TBAP / ODCB solution and performing argon bubbling for 20 minutes, under an argon atmosphere in an H-type cell in which three kinds of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE) are set) Electrolysis was carried out at +0.8 V to synthesize a cation of La @ C ₈₂ -B, and the ultraviolet-visible-near-infrared absorption spectrum of the cation [FIG.
Was measured.

Example 5 1 mg of the metal-encapsulated fullerene Pr @ C ₈₂ -A isomer was added to 0.1 mg.
After dissolving in 8 mL of 2M TBAP / ODCB solution and performing argon bubbling for 20 minutes, under an argon atmosphere in an H-type cell in which three kinds of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE) are set) Electrolysis was performed at 0 V to synthesize an anion of Pr @ C ₈₂ -A. The UV-visible-near infrared absorption spectrum of the anion (FIG. 9A) and the nuclear magnetic resonance spectrum (FIG. 10) were measured.

Example 6 1 mg of the metal-encapsulated fullerene Pr ＠ C ₈₂ -A isomer was added to 0.1 mg.
After dissolving in 8 mL of 2M TBAP / ODCB solution and performing argon bubbling for 20 minutes, under an argon atmosphere in an H-type cell in which three kinds of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE) are set) Electrolysis was performed at +0.8 V to synthesize a cation of Pr @ C ₈₂ -A, and the ultraviolet-visible-near-infrared absorption spectrum of the cation (FIG. 9B) was measured.

Example 7 1 mg of the metal-encapsulated fullerene Pr @ C ₈₂ -B isomer was added in 0.1 mg.
2M TBAP / ortho-dichlorobenzene ODCB solution
After dissolving in 8 mL and performing argon bubbling for 20 minutes, electrolysis was performed at 0 V under an argon atmosphere in an H-type cell in which three types of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE)) were set. Pr @ were synthesized anions of C _{8 2} -B. ultraviolet-visible-near infrared absorption spectrum of the anion [FIG 11 (a)] measurements were performed.

Example 8 1 mg of the metal-encapsulated fullerene Pr @ C ₈₂ -B isomer was added to 0.1 mg.
After dissolving in 8 mL of 2M TBAP / ODCB solution and performing argon bubbling for 20 minutes, under an argon atmosphere in an H-type cell in which three kinds of electrodes (Pt working electrode, Pt auxiliary electrode, and reference calomel electrode (SCE) are set) Electrolysis was performed at +0.8 V to synthesize a cation of Pr @ C ₈₂ -B.UV-NIR absorption spectrum of the cation [FIG.
Was measured.

Example 9 1 m of an ODCB solution of 1.5 × 10 ⁻⁵ M La @ C ₈₂ -A anion
After freeze degassing L, the tube was sealed in a UV cell, and NIR was measured. After heating in an oven at 150 ° C. for 10 minutes, an ultraviolet-visible-near-infrared absorption spectrum was measured, but no change was observed. Further heating at 170 ° C. for 10 minutes showed that the anions were stable. These facts revealed that this anion was thermally stable [FIG. 12 (a)].

Example 10 1 m of an ODCB solution of 1.5 × 10 ⁻⁵ M La @ C ₈₂ -A anion
After freeze-degassing L, the tube was sealed in a UV cell, and an ultraviolet-visible-near-infrared absorption spectrum was measured. Light irradiation of 500nm or more
After irradiation with light of 400 nm or more for 1 minute and 5 minutes, the ultraviolet-visible near-infrared absorption spectrum was measured, but no change was observed. Next, when light irradiation of 300 nm or more was performed for 1 minute, absorption around 950 nm derived from anions disappeared. In addition, mass analysis of this solution showed that La ＠ C
A signal corresponding to _82- A was obtained. From these results, it was clarified that the anion was stable to light of 400 nm or more, but that it rapidly formed a polymer by polymerization reaction or the like when irradiated with light of 300 nm or more [FIG. 12 (b)].

Example 11 1 m of an ODCB solution of 1.5 × 10 ⁻⁵ M La @ C ₈₂ -A anion
The NIR of L was measured and used as the initial value. Phenol (pKa = 10), thiophenol (pKa = 8), p
Addition of -nitrophenol (pKa = 7) and 2,4-dinitrophenol (pKa = 4) did not change the ultraviolet-visible-near-infrared absorption spectrum. From these facts, La
The ＠C ₈₂ -A anion was found to be stable in weak acids. It has been confirmed that it is stable even in water. On the other hand, when acetic acid (pKa = 5) was added, a slight decrease in absorption was observed. Dichloroacetic acid (pKa = 1)
Was added, the disappearance of the anion absorption around 950 nm and 1
Absorption by La @ C ₈₂ -A appeared around 000 nm. That is, it was clarified that oxidation was quickly performed by a strong acid. FIG. 13 shows the changes in the spectrum when La @ C ₈₂ -A (-) and the above compounds were added.

Example 12 ODCB solution of 1.5 × 10 ^-5 M La @ C ₈₂ -B anion 1
After freezing and degassing the mL, the tube was sealed in a UV cell, and an ultraviolet-visible-near-infrared absorption spectrum was measured. After heating in a 125 ° C. oven for 10 minutes, the ultraviolet-visible-near infrared absorption spectrum was measured, but no change was observed. 1 at 160 degrees
Upon heating for 0 minutes, the anions were stable. These facts revealed that this anion was thermally stable [FIG. 14 (a)].

Example 13 ODCB solution 1 of 1.5 × 10 ^-5 M La @ C ₈₂ -B anion
After freezing and degassing the mL, the tube was sealed in a UV cell, and an ultraviolet-visible-near-infrared absorption spectrum was measured. Light irradiation of 400nm or more
After 10 minutes, the ultraviolet-visible near-infrared absorption spectrum was measured, but no change was observed. Next, when light irradiation of 300 nm or more was performed for 30 seconds, absorption due to anions disappeared. In addition, mass analysis of this solution showed that La
A signal corresponding to ΔC ₈₂ -B was obtained. From these facts, the anion is stable to light of 400 nm or more,
It was clarified that light irradiation of nm or more quickly formed a polymer by polymerization reaction or the like [FIG. 14 (b)].

Example 14 1 m of ODCB solution of 1.5 × 10 ⁻⁵ M La @ C ₈₂ -A anion
L is desorbed from excess adamantyldiazirine (reaction formula 1) and diphenyldiazomethane (reaction formula 2)
The tube was sealed in a cell, and an ultraviolet-visible-near-infrared absorption spectrum was measured. The reaction did not proceed at room temperature,
Upon heating, absorption due to anions disappeared.
When the mass spectrometry of this solution was performed, the formation of an adduct (1 to 3 was added) was clarified.

[0023]

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[0024]

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Examples 15 and 16 Anthracene and acetylene derivatives (CH ₃ OOC≡)
COOCH ₃ ) was also reacted under the same conditions as in Example 14, and the formation of an adduct was confirmed as in Example 14.

Examples 17 and 18 The La @ C ₈₂ anion (n-Bu ₄ N cation) was insoluble in water.
Stable to water and stable in air, but decomposed by dimethyl sulfate [(CH ₃₀ ) ₂ SO ₂ ]. The La @ C ₈₂ anion can be oxidized by a chemical oxidizing agent (p-BrC ₆ H ₄ ) ₃ ⁺ SbCl ₆ ⁻ to form a metal-encapsulated fullerene from the anion. Furthermore, metal-encapsulated fullerene neutral, chemical oxidants _{(p-BrC 6 H 4)} 3 + SbCl 6 - is oxidized, it is possible to generate cations from neutral body.

From these facts, it is suggested that the metal-encapsulated fullerene of the present invention is stable and easy to handle, and can be effectively used as a reagent for promoting the reaction under controlled conditions. .

[0028]

As described above, the cationic and anionic species of the metal-encapsulated fullerene of the present invention are stable fullerenes each having a closed shell structure, so that they are easy to handle. Furthermore, by redox of anionic species and cationic species, it can be converted to a metal-encapsulated fullerene derivative having an original open shell structure. That is, the cation species and the anion species of the metal-encapsulated fullerene are:
It has both the electronic properties of metal-encapsulated fullerenes derived from the transfer of electrons from internal metal atoms to the carbon gauge and the electronic properties of empty fullerenes themselves. From these facts, through the development of a new method for converting a metal-encapsulated fullerene into a molecule, an excellent effect is expected that the metal-encapsulated fullerene is expected to be applied to a functional material, a raw material for synthesizing a pharmaceutical derivative, a highly active catalyst, and the like.

[Brief description of the drawings]

FIG. 1 is an ultraviolet-visible-near-infrared absorption spectrum of La @ C ₈₂ -A and Pr @ C ₈₂ -A.

FIG. 2 is an ultraviolet-visible-near-infrared absorption spectrum of La @ C ₈₂ -B and Pr @ C ₈₂ -B.

FIG. 3. Electron spin resonance (ESR) spectra of La @ C ₈₂ -A and La @ C ₈₂ -B

FIG. 4 La ＠ C ₈₂ -A (−), La ＠ C ₈₂ -A
UV-visible near-infrared absorption spectrum of (+) and La @ C ₈₂ -A

FIG. 5 ¹³ C NMR spectrum of La @ C ₈₂ -A (-)

FIG. 6: DPV of La @ C ₈₂ -A

FIG. 7: La @ C ₈₂ -B (-), La @ C ₈₂ -B
(+) And La @ C ₈₂ -B of the ultraviolet-visible-near-infrared absorption spectrum

FIG. 8 ¹³ C NMR spectrum of La @ C ₈₂ -B (-)

FIG. 9: Pr @ C ₈₂ -A (-), Pr @ C ₈₂ -A
Ultraviolet-visible-near-infrared absorption spectrum of (+) and Pr @ _C82- A

FIG. 10 ¹³ C NMR of Pr @ C ₈₂ -A (-)

FIG. 11 Pr ＠ C ₈₂ -B (−), PrＰC ₈₂ -B
Ultraviolet-visible-near-infrared absorption spectrum of (+) and Pr @ C82-B

FIG. 12 shows the stability of La @ C ₈₂ -A (-) to (a) heat and (b) light.

FIG. 13 Stability of La @ C ₈₂ -A (−) to acids

FIG. 14 shows the stability of La @ C ₈₂ -B (−) to (a) heat and (b) light.

Claims (3)

[Claims] 1. A general formula M ＠ Cn (where M = Sc, Y, L) in which an electronic structure formed by an electrolytic method is a closed shell structure.
a, lanthanide element, actinoid element, n = 60, 7
Metal-encapsulated fullerene ion represented by an even number of 0 or more). 2. The metal-encapsulated fullerene ion according to claim 1, wherein n is 82. 3. The metal-encapsulated fullerene ion according to claim 1, wherein M is La or Pr.