JP2016124712A - Metal atom-encapsulating fullerene generation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To encapsulate a metal atom in a fullerene molecule and make it possible to separate the fullerene molecule encapsulating the metal atom from a fullerene molecule not encapsulating the metal atom.SOLUTION: A fullerene ion beam, including a fullerene molecule f not encapsulating a metal atom, is made incident on an ion beam incident port IN of an ion beam flow channel 1 with a compound including the metal atom M adsorbed on the surface of the inner wall thereof. Thereby the fullerene molecule f encapsulates the metal atom M via collision with the inner wall, and a fullerene ion beam, including a fullerene molecule F encapsulating the metal atom M, is emitted from an ion beam emission port OUT of the ion beam flow channel 1. The orbit of the fullerene molecule F is controlled according to the mass, velocity, and electric charge.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique that enables separation from fullerene molecules that contain metal atoms in fullerene molecules but do not.

  Conventionally, as a technique for encapsulating atoms in fullerene molecules, a method is often used in which a compound containing atoms to be encapsulated in fullerene vapor is turned into plasma and the reaction product is deposited on a solid surface such as a substrate, electrode, or reactor wall. It was done.

  For example, Patent Document 1 proposes the inclusion reaction in plasma and the substrate deposition of inclusion fullerene by plasma flow irradiation. Attempts have also been made to increase the inclusion probability by using not only plasma but also electron beam or ultraviolet light irradiation.

  For example, Patent Document 2 attempts to generate nickel atom-containing fullerene molecules using an electron beam and plasma, and Patent Document 3 attempts to generate metal atom-containing fullerenes by irradiating metal vapor plasma with ultraviolet light. There has also been proposed a method in which a gas phase reaction in plasma is included, followed by separation and extraction as an atomically-encapsulated molecular ion beam, and irradiation and deposition on the substrate. In this method, only the molecular ions having the same mass as the encapsulated molecules can be selectively extracted by mass spectrometry using a magnetic field, so that highly pure encapsulated molecules can be deposited.

  For example, in Patent Document 4, a material (gas, solid) containing encapsulated atoms and fullerene molecules are mixed in an electron cyclotron resonance plasma (ion source), and then separated as particles having the same mass as the encapsulated fullerene ions. A deposition method is employed.

  In addition, as disclosed in Patent Document 5, there is a method in which a metallocene molecule having a molecular structure in which metal atoms are sandwiched by two five-membered rings is reacted with fullerene molecules in order to encapsulate metal atoms efficiently. This is not a strong chemical bond, but a metal atom is extracted from a weakly bonded metal compound by van der Waals force and is included in fullerene molecules by high pressure heating synthesis method, gas phase synthesis method, plasma synthesis method, etc. .

  On the other hand, as disclosed in Patent Document 6, an ion implantation method is proposed in which atoms to be encapsulated are accelerated by ionization after ionization and are implanted into target fullerene molecules instead of being encapsulated by plasma. Yes. Since this method uses an ion beam, it is easy to control the energy and irradiation conditions at the time of implantation, and the inclusion probability can be increased by setting the optimum conditions.

JP 2005-325015 A JP 2013-035725 A JP 2006-222078 A JP 2010-277871 A JP 2008-007373 A JP 2002-255518 A

  As described above, in the prior art, the inclusion reaction is mostly carried out in the plasma (or in the gas phase), but since various atoms, molecules, and active species move in the plasma at various speeds and directions, the inclusion reaction occurs. There is a problem that it is difficult to control the reaction. That is, it is almost impossible in plasma to encapsulate only desired atoms in a desired molecule, and therefore it is difficult to isolate and purify a desired encapsulated molecule.

  On the other hand, in the ion implantation method that does not use plasma, the inclusion efficiency can be increased by optimization, but it is difficult to separate and purify the inclusion fullerene molecules from the deposited fullerene molecules.

  An object of this invention is to provide the technique which enables isolation | separation with the fullerene molecule which encapsulates a metal atom in a fullerene molecule and does not encapsulate in view of said situation.

  The metal atom-encapsulating fullerene generating apparatus of the present invention includes an ion beam flow path having an ion beam incident port for receiving a fullerene ion beam including ionized fullerene molecules and an ion beam emitting port for emitting the fullerene ion beam, A metal atom to be included in the fullerene molecule is included in the inner wall of the ion beam channel in advance, and when the fullerene ion beam collides with the inner wall, the metal atom is included in the fullerene molecule, and the metal atom is included. The fullerene ion beam containing the fullerene molecule is emitted from the ion beam outlet.

  According to the present invention, if a desired metal atom is included in the inner wall of the ion beam channel in advance and a fullerene ion beam including fullerene molecules is incident on the ion beam entrance, the fullerene molecules collide with the inner wall and the metal molecules Since the fullerene ion beam containing the fullerene molecule containing the metal atom is emitted from the ion beam exit, the fullerene molecule containing the metal atom is not included by controlling the trajectory of the fullerene ion beam. Can be separated from fullerene molecules.

It is a conceptual diagram of the metal atom inclusion fullerene production | generation apparatus which concerns on this Embodiment. It is a figure which shows the molecular structure of a metallocene SAM film | membrane. It is a figure which shows the specific example of a metal atom inclusion fullerene production | generation apparatus. 1 is a diagram illustrating an example of a structure of an ion beam flow path 1. It is a figure which shows an example of the two-dimensional image which imaged the fullerene molecule radiate | emitted from the ion beam exit port OUT. It is a figure which shows an example of distribution of the flight time of a fullerene molecule. It is a figure which shows the two-dimensional image which selected and imaged only the fullerene molecule | numerator of the spectrum B shown in FIG. It is a figure of a modification.

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

  In the metal atom-encapsulating fullerene generating apparatus according to the present embodiment, the reaction of encapsulating metal atoms in fullerene molecules is not performed in plasma. For example, ionized fullerene molecules (hereinafter simply referred to as fullerene molecules) on a solid surface that has adsorbed metal atoms. This is performed by colliding with a fullerene ion beam containing. Since the fullerene ion beam is incident on the solid surface as a beam having a uniform velocity (equivalent to energy) and direction, the reaction is easier to control than the plasma. Further, since the fullerene ion beam is reflected in a specific direction on the solid surface, the fullerene molecules encapsulating metal atoms can be separated from the fullerene molecules not encapsulating by sorting the fullerene molecules by mass or the like. Therefore, fullerene molecules encapsulating metal atoms can be deposited on the substrate in a highly purified state.

  Furthermore, in order to allow the fullerene molecule to efficiently encapsulate metal atoms and to be easily separated and purified, in this embodiment, the following three original methods are performed.

  1. In order to collide fullerene molecules and metal atoms many times at a low speed, as shown in FIG. 1A, the entrance of the ion beam channel 1 (ion beam entrance IN IN) in which a compound containing metal atoms is adsorbed on the surface of the inner wall. In contrast, a fullerene ion beam containing fullerene molecules f not containing metal atoms as shown in FIG. As a result, the fullerene molecules collide with the inner wall and the metal molecules are included, and the metal atoms M as shown in FIG. 1C are included from the exit of the ion beam channel 1 (referred to as the ion beam exit OUT). A fullerene ion beam containing fullerene molecules F is emitted.

  The ion beam channel 1 is a guide that controls the traveling direction of the fullerene ion beam by utilizing reflection / scattering on a solid surface. For example, a curved convex surface and a curved concave surface as shown in FIG. Is a narrow gap that can be formed by facing each other with a gap of about several mm or less. The compound containing the metal atom M is adsorbed on the convex and concave surfaces, and the fullerene ion beam is incident on the ion beam flow path 1, whereby the fullerene molecule f and the metal atom M collide many times at a small angle. . As a result, fullerene molecules F containing metal atoms M are emitted from the ion beam flow path 1.

  2. As the compound containing the convex surface and the metal atom M adsorbed on the concave surface, for example, a self-assembled monomolecular film in which a metallocene molecule having a molecular structure as shown in FIG. A metallocene molecule in which a metal atom M such as iron, cobalt, nickel or the like is sandwiched between two carbon five-membered rings is bonded to a thiol molecule (or a derivative thereof) to terminate the thiol terminated with a metallocene molecule on the outermost surface. A self-assembled monolayer (metallocene SAM film) of molecules (or derivatives thereof) can be formed. Since the metal atom M sandwiched between the five-membered carbon rings is weakly bonded to the outermost surface, it is expected that the metal atom M is likely to be included by collision with the fullerene molecule.

  3. In order to separate and purify the fullerene ion beam after the inclusion of the metal atom M, the fullerene molecules of the fullerene ion beam that has passed through the ion beam flow path described above are caused to fly in an electromagnetic field, and according to the mass, velocity, and charge. Deposit in different places.

  In this embodiment, by using a fullerene ion beam without using plasma, it becomes easy to optimize the inclusion conditions, and the inclusion reaction can be controlled to a high degree.

  In addition, 1. As shown in FIG. 2, since the fullerene ion beam and the metal atom M collide many times at a small angle in the ion beam flow path 1, the inclusion probability can be increased.

  In addition, 2. As shown in FIG. 5, by using a self-assembled monolayer, a target in which metal atoms M that are weakly bonded by van der Waals force cover the outermost surface with high density can be realized, so that the inclusion probability of metal atoms M is increased. be able to.

  3. As shown in FIG. 2, since the fullerene ion beam containing the metal atom M can be separated by controlling the flight trajectory by the mass, velocity, and charge, the fullerene molecule containing the metal atom M is purified to a high purity. Can be deposited on a substrate.

  Such fullerene molecules encapsulating metal atoms M can be used, for example, for contrast media in magnetic resonance imaging (MRI) and drug delivery in the body in a drug delivery system (DDS). Can do.

  As shown in FIG. 3, the metal atom inclusion fullerene generation device of the specific example is a pulse electrode that guides the ion beam channel 1 and the fullerene ion beam B to the entrance of the ion beam channel 1 (referred to as ion beam entrance IN). 2. An electromagnetic field generator 3 for generating an electromagnetic field for controlling the trajectory of the fullerene ion beam B emitted from the exit of the ion beam channel 1 (referred to as an ion beam exit OUT) is provided.

  The ion beam flow path 1, the pulse electrode 2 and the electromagnetic field generator 3 are arranged in a vacuum chamber 4. In the traveling direction of the fullerene ion beam B after the trajectory control, a deposition substrate 5 on which fullerene molecules containing metal atoms M are deposited is disposed. The deposition substrate 5 is also disposed in the vacuum chamber 4.

  For example, a self-assembled monomolecular film (metallocene SAM film) terminated with the above-described metallocene molecule or a derivative thereof is adsorbed on the inner wall of the ion beam channel 1.

  Fullerene molecules containing metal atoms that have passed through the ion beam exit OUT pass through the electromagnetic field generator 3 for mass / velocity / charge selection as shown in FIG. Accordingly, the track is separated in a direction perpendicular to the paper surface of FIG. 3 and then deposited on the deposition substrate 5. That is, the fullerene molecule containing the metal atom is heavy and difficult to bend, but the fullerene molecule not containing the metal atom or the broken fullerene molecule is light and is bent greatly. Thus, separation and purification are easy because the fullerene molecules are deposited on the deposition substrate 5 while being sorted.

  Prior to the present application, a verification test was conducted. In the verification test, a two-dimensional position sensitive radiation detector (2D-PSD) is installed in place of the deposition substrate 5 in FIG. 3, and the ion beam channel 1 has a structure as shown in FIG. Road).

  As shown in FIG. 4, the ion beam channel 1 includes a member 11 having a curved convex surface and a member 12 having a curved concave surface. The convex surface and the concave surface face each other. The gap between the convex surface of the member 11 and the concave surface of the member 12 is curved, whereby the collision between the fullerene ion beam B and the inner wall (convex surface and concave surface) can be promoted.

  A hole is formed in the plate-like member 13, and the hole constitutes the ion beam entrance IN.

  The diameter of the fullerene ion beam B is, for example, 1.0 mm, and the diameter of the ion beam incident port IN is, for example, 1.5 mm.

  The fullerene ion beam B is incident from the hole (ion beam entrance IN) of the member 13. When the traveling direction is Z, the direction in which the members 11 and 12 face each other is Y, and the direction perpendicular to the Z direction and the Y direction is X, the lengths of the members 11 and 12 in the X and Z directions are, for example, 20.0 mm. The gap between the member 11 and the member 12 is, for example, 1.2 mm.

A thiol SAM film of ferrocene molecules (M = Fe) was adsorbed on the inner walls (convex surface and concave surface) of the members 11 and 12. Then, in order to measure the time of flight of fullerene molecules emitted from the ion beam exit OUT, a pulse voltage is applied to the pulse electrode 2 in FIG. 3, and a C ₆₀ ²⁺ fullerene ion beam B having energy of 4.8 keV is applied. The incident light was incident on the ion beam inlet IN for a time width (full width at half maximum) of 0.2 μs (1 μs is one millionth of a second). Then, the inclination of the ion beam flow path 1 with respect to the fullerene ion beam B was changed so that the tilt angle θ around the X axis in FIG.

  FIG. 5 is a two-dimensional image obtained by imaging fullerene molecules emitted from the ion beam exit port OUT by 2D-PSD when the tilt angle θ is −2 °. In this image, as shown in the legend, the shading is changed by a multiple of the predetermined number of fullerene molecules.

  FIG. 6 shows the flight time distribution of the fullerene molecules, where the horizontal axis TOF is the flight time and the vertical axis Count is the count value.

  In this demonstration test, the simplest two parallel plate electrodes were employed as the electromagnetic field generator 3 of FIG. By applying an electrostatic field of 40 V / cm between the parallel plate electrodes, the trajectory of the fullerene molecules after passing through the ion beam flow path 1 is changed from the front to the back of FIG. 3 (that is, the X axis in FIG. 4). In the negative direction) according to mass, velocity and charge. An AC electromagnetic field may be applied instead of the electrostatic field.

  For reference, when no electrostatic field was applied and the tilt angle θ was 0 °, the fullerene molecules reached the position of X = 5 mm and Y = 5 mm (position of the circle 51 in FIG. 5). Therefore, the “contrast-shaped” distribution with strong contrast seen around X = −20 mm and Y = 5 mm in FIG. 5 does not pass through the ion beam channel 1 even when the tilt angle θ is tilted to −2 °. It is a fullerene molecule that has passed straight through.

  In addition, since there are almost no fullerene molecules in the vicinity of X = 5 mm, almost all of the fullerene molecules that have passed through the ion beam channel 1 remain in an ionic state, indicating that neutralization has not occurred. .

  On the other hand, the small island-like distribution with low contrast seen around X = −10 mm and Y = 16 mm surrounded by a circle 52 in FIG. 5 is considered to be a fullerene molecule containing iron metal atoms.

  The result supporting this is the flight time distribution of FIG.

  It has been theoretically found that the flight time when the fullerene molecule permeates without impinging on the inner wall of the ion beam channel 1 is 12.7 μs. It can be considered that the spectrum A having a large intensity of 12.5 to 12.9 μs seen in FIG. 6 corresponds to this. The time width (full width) of about 0.4 μs of this spectrum corresponds to the pulse width of the fullerene ion beam incident on the ion beam channel 1 (twice the full width at half maximum).

  On the other hand, if it is assumed that momentum conservation between the fullerene molecule and the iron metal atom holds, the flight time of the fullerene molecule after collision (= completely inelastic collision) is theoretically 13.3 μs, and the fullerene does not contain metal atoms. 0.6 μs longer than the time of flight of the molecule. This is because the speed of the fullerene molecule which has become heavy due to the inclusion of metal atoms by collision is lower than the speed of the fullerene molecule which does not collide and does not contain metal atoms. And it is thought that the small spectrum B seen in 12.9-13.4 microseconds of FIG. 6 is equivalent to the fullerene molecule which included the metal atom by collision and became heavy. Actually, when only the fullerene molecules in the spectrum B are selected and a two-dimensional image is generated in the same manner as in FIG. 5, it can be seen that many fullerene molecules gather near X = −10 mm and Y = 16 mm as shown in FIG. . Therefore, it is considered highly likely that the fullerene molecules gathered at this position are fullerene molecules including iron metal atoms.

  From this verification test result, it has been experimentally verified that there is a high possibility that fullerene molecules bonded with at least iron metal atoms are emitted from the ion beam outlet OUT of the ion beam channel 1. In the future, we will continue to verify the inclusion by repeating additional tests with higher measurement accuracy and conducting various analyzes on the deposited fullerene molecules.

(Modification)
For example, the fullerene molecule used in the present embodiment can be applied to any cage-type molecule that can be made into an ion beam, such as a carbon-skeleton cage molecule and its derivatives, and a silicon-skeleton cage molecule. is there.

  Moreover, as a metal atom, suitable things according to a use, such as cobalt, nickel, and yttrium, can be used in addition to iron.

  In addition to the ion beam flow path 1 shown in FIG. 4, it is also effective to use an ion beam flow path whose inside is narrower as it is closer to the ion beam exit port OUT as shown in FIG. Thereby, the collision between the fullerene molecule f incident from the ion beam entrance IN and the inner wall surface of the ion beam channel 1 can be promoted. As a result, it is possible to increase the probability that the fullerene molecule F encapsulating metal atoms is emitted from the ion beam exit port OUT.

  Further, if it is narrower as it is closer to the ion beam exit OUT, as shown in FIG. 8 (b), the fullerene molecule f and the ion beam flow path can be obtained even when the inner wall is not curved and is configured as a plane. The collision of the inner wall surface of 1 can be promoted.

  As the electromagnetic field generator 3, in addition to the parallel plate electrodes employed in the verification test, two magnetic poles (pole pieces) installed in the vertical direction (that is, the Y-axis direction) in FIG. 3 are also effective. In addition, it is effective to share the parallel plate electrode and the magnetic pole.

  The pulse electrode 2 in FIG. 3 is a time-of-flight measurement device installed to verify that the ions that have reached the position 52 in FIG. 5 are iron-encapsulated fullerene ions in the verification test. It is not necessary for practical purposes to generate atomic inclusion fullerenes.

  Furthermore, in order to deposit fullerene molecules encapsulating metal atoms on the deposition substrate without breaking them, it is also effective to bring the potential of the deposition substrate and ion beam flow path close to the acceleration potential of the fullerene ion beam and make the potential difference about 100 V or less. is there.

DESCRIPTION OF SYMBOLS 1 Ion beam flow path 2 Electrode for pulses 3 Electromagnetic field generator 4 Vacuum chamber 5 Deposition substrate B Fullerene ion beam f Fullerene molecule not containing metal atom F Fullerene molecule containing metal atom M Metal atom IN Ion beam entrance OUT Ion beam Outlet

Claims (5)

An ion beam flow path having an ion beam entrance for entering a fullerene ion beam containing ionized fullerene molecules and an ion beam exit for emitting the fullerene ion beam;
A metal atom to be included in the fullerene molecule is included in the inner wall of the ion beam channel in advance, and when the fullerene ion beam collides with the inner wall, the metal atom is included in the fullerene molecule, and the metal atom is A metal atom-encapsulating fullerene generating device, wherein a fullerene ion beam containing fullerene molecules encapsulated is emitted from the ion beam exit. 2. The metal atom-encapsulated fullerene production according to claim 1, wherein the inner wall adsorbs a self-assembled monolayer of a thiol molecule or a derivative of a thiol molecule terminated with a metallocene molecule containing the metal atom. apparatus. The metal ion inclusion fullerene generation device according to claim 1, wherein the ion beam flow path is curved or becomes narrower as it is closer to the ion beam exit. 4. The metal atom-containing fullerene generation according to claim 1, further comprising an electromagnetic field generator that generates an electromagnetic field for controlling a trajectory of the fullerene ion beam emitted from the ion beam exit. 5. apparatus. 5. The deposition substrate on which fullerene molecules including the metal atoms contained in the fullerene ion beam after trajectory control by the electromagnetic field generator are to be deposited is arranged in a traveling direction of the fullerene ion beam. The metal atom inclusion fullerene production | generation apparatus of description.