JPH07120419A - Measuring method for substance containing carbon fluorine and hydrogen by nuclear magnetic resonance - Google Patents

Abstract

PURPOSE:To provide a nuclear magnetic resonance spectrum being easily analysed by using two pairs of squarely crossing coils and a probe capable of measuring <2>H, and measuring a substance while decoupling in a wide range. CONSTITUTION:Signals from oscillators 1-4 are supplied to high frequency amplifiers 10-13, through high frequency gate units 6-9 driven by a pulse generator 5. The signals of the oscillator 1 for <13>C and the oscillator 2 for <19>F are supplied to the inside coil 15 of a probe 14, and the signals of the oscillator 3 for <1>H and the oscillator 4 <2>H for obtaining a lock signal for stabilizing a magnetic field are supplied to the outside coil 16. An observation receiver 17 for <13>C and an observation receiver 18 for <19>F are connected to the coil 15, an observation receiver 19 for <1>H and a receiver 20 for lock signal are connected to the coil 16, and different frequencies can be simultaneously impressed to the probe from the four oscillators. Respective radio cycles of the oscillators 3, 2 and 4, 1 are impressed to separate coils so as to make the electrostatic combination to the minimun, and hence <13>C, <19>F, <1>H can be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear magnetic resonance measuring method, and more particularly to a nuclear magnetic resonance measuring method for a compound containing three kinds of nuclei of ¹³ C, ¹⁹ F and ¹ H.

[0002]

2. Description of the Related Art Fluorine-containing compounds have unique properties that cannot be obtained by general compounds having a basic carbon-hydrogen bond, and many fluorine-containing compounds utilizing these unique properties have been developed. Has been done. However, ¹³ C, ¹⁹
As measured by a nuclear magnetic resonance apparatus for the purpose of structural analysis such as fluorine compound containing F and ¹ H, due to the spin coupling of ¹⁹ F is ^{complex, 19 F- 13 C, 1 H-} 13 C, 19
Even in heteronuclear correlation nuclear magnetic resonance such as F- ¹ H, ¹⁹ F
The spectra obtained by the complex spin coupling from are very complicated and their analysis is extremely difficult.

In such heteronuclear-nuclear-correlation nuclear magnetic resonance, radio waves having different frequencies are simultaneously irradiated, and the coupling of one of the nuclides is removed by a radio wave of high intensity, and the other nuclide is observed by decoupling. Being measured.
For example, in the measurement of ¹³ C, by performing the decoupling between the hydrogen nuclei, it has been made to obtain a single spectrum of ¹³ C.

If ¹⁹ F can be decoupled during the detection time of two-dimensional nuclear magnetic resonance, it can be expected that the spectrum can be simplified and the analysis can be facilitated. However, the chemical shift range of ¹⁹ F is wide and the entire range is once. This method also could not be applied because it could not be decoupled.

[0005]

SUMMARY OF THE INVENTION An object of fluorine useful for structural analysis of organic substances containing an ^{19 F- 13 C, 1 H- 13} C,
^In heteronuclear correlation nuclear magnetic resonance such as ¹⁹ F- ¹ H, ¹⁹ F
It is an object to obtain a nuclear magnetic resonance spectrum that can be easily analyzed by performing a measurement excluding complicated spin coupling from.

[0006]

[Means for Solving the Problems] Carbon by nuclear magnetic resonance,
In a method of measuring a substance containing fluorine and hydrogen, a probe capable of measuring ¹³ C, ¹⁹ F and ¹ H, which is composed of two pairs of orthogonal coils, and ² H for forming a stable magnetic field is used, and a pulse train is configured. Method of measuring substances containing carbon, fluorine and hydrogen by nuclear magnetic resonance, irradiating a pulse train having a broadband frequency component obtained by changing the frequency and phase of each pulse to be measured while performing decoupling over a wide range Is. In addition, one coil is for ¹⁹ F or ¹ H and ¹³ C, and the other coil is for ¹ H or ¹⁹ F and ² H. Further, it is a measuring method characterized by performing magnetization transfer from ¹⁹ F or ¹ H to ¹³ C.

[0007]

[Function] The probe for nuclear magnetic resonance measurement is provided with measuring coils of ¹ H and ¹⁹ F, which have similar resonance frequencies, at positions where mutual mutual electrostatic coupling is reduced, and ¹³ C and ² H
The coil is also provided at a position where mutual mutual electrostatic coupling is reduced, and a pulse having a broadband pulse component is irradiated to completely decouple the chemical shift of fluorine to obtain a spectrum easy to analyze.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of main components of a nuclear magnetic resonance apparatus for carrying out the method of the present invention. The nuclear magnetic resonance apparatus has radio frequency generators of a ¹³ C oscillator 1, a ¹⁹ F oscillator 2, a ¹ H oscillator 3 and a ² H oscillator 4, and a signal from each oscillator is a pulse generator 5. It is supplied to the high frequency amplifiers 10 to 13 through the high frequency gate units 6 to 9 driven by the pulse from. The signal from the ¹³ C oscillator and the signal from the ¹⁹ F oscillator are supplied to the inner coil 15 provided in the probe 14. Further, the signal from the ¹ H oscillator and the signal from the ² H oscillator for obtaining the lock signal for stabilizing the magnetic field are supplied to the outer coil 16, and the inner coil 15 includes the ¹³ C observation receiver 17 , ¹⁹ F
Observation receiver 18 is connected to the outer coil,
^{The 1} H observation receiver 19 and the lock signal receiver 20 are connected, and different frequencies can be simultaneously applied to the probe from the four oscillators. Also, for example, 9.4
In the case of the magnetic field of T, the ¹ H oscillator uses the frequency of 400 MHz and the ¹⁹ F oscillator uses the frequency of 376 MHz. Since the resonance frequencies are close to each other, it is difficult to double-tune the two resonance frequencies. is there. Therefore, it is necessary to separately apply these radio frequencies to two coils arranged so as to minimize mutual electrostatic coupling.
Similarly, ² H Oscillator using 60 MHz, ¹³ C
Use oscillators, because it uses 100 MHz, these by applying to the separate coils ¹³ C, ¹⁹ F, ¹
It becomes possible to measure H.

FIG. 2 is a view for explaining an arrangement example of coils inside the probe. The pair of inner coils 15 and the pair of outer coils 16 are arranged to be orthogonal to each other and to minimize electrostatic coupling. Further, it is preferable to dispose a nuclide measuring coil having a low abundance ratio inside the sample, and generally to dispose a ¹³ C coil inside. In the above example, the inner coil 15 is used for ¹³ C and ¹⁹ F, and the outer coil 16 is used for ¹ H and ² H, respectively. However, ¹ H and ¹⁹ F whose frequencies are close to each other are separated. The other ¹³ C and ² H may be in the opposite combination if in charge. For example, the inner coil 15 may be used for ¹³ C and ¹ H, and the outer coil 16 may be used for ¹⁹ F and ² H.

The most typical measurement by correlated nuclear magnetic resonance between ¹ H, ¹⁹ F, and ¹³ C is F—C or H—C cosY in a decoupled state of ¹ H or ¹⁹ F. In either case, the development time (t ₁ ) is ¹⁹ F or
It develops with a chemical shift of ¹ H, and the detection time (t ₂ ) is ¹ H
Both ¹⁹ and ¹⁹ F need to be decoupled, but ¹ H
When ¹⁹ F both chemical shifts throughout to decouple, when applied simultaneously both resonance frequency of the ¹ H and ¹⁹ F, since heat generated by the dielectric loss is expected power applied must be as small as possible. Therefore, in the measurement method by nuclear magnetic resonance of the present invention, the MPF proposed by the present applicant is used.
It is necessary to apply a wideband decoupling method such as wideband decoupling with a (phase frequency modulation) sequence. These are disclosed in JP-A-3-148080, J. Magn. Reson. 77 , 53, (198
8), J. Magn. Reson. 104 , 103,
By simultaneously controlling the frequency and phase of each pulse as described in (1993) etc., a wideband decoupling pulse is obtained.

An example of such a decoupling pulse train is shown in Table 1. In Table 1, since the pulse train is symmetric with respect to the reference frequency, only the first half of the symmetrical rectangular continuous pulse is shown. The magnetic field strength B of each pulse in the pulse train is constant irrespective of time, and the phase is FM coordinate system (coordinate system represented by the frequency at each offset).
Is defined in. The unit of radio frequency is γB, and the unit of pulse width and phase is degree. The ordinal number at the top indicates the order of the rectangular pulse in a certain pulse train. The second half of the pulse train is 2n
In a pulse train consisting of rectangular pulses, P (j), φ
(J) and f (j) are the j-th pulse width, phase,
Letting frequency be P (2n + 1-j) = P (j), φ
(2n + 1-j) = φ (j), f (2n + 1-j) =-
f (j), represented by (1 ≦ j ≦ n).

[0012]

[Table 1]

Further, FIG. 3 shows a measurement sequence using a pulse train for wideband decoupling. In this measurement sequence, ¹ H or ¹⁹ F is decoupled by hatching, ¹³ C is measured together with ¹⁹ F or ¹ H, or ¹³ C in the state where both ¹⁹ F and ¹ H are decoupled is measured. It shows that measurement is possible.

FIG. 4 shows F—C cosY { ¹ H} obtained by measuring an organic compound (vinylidene fluoride rubber) containing fluorine and hydrogen by using the pulse sequence of FIG.
Further, H-C cosY { ¹⁹ F} is shown in FIG. The ¹⁹ F signal for this compound is distributed in the chemical shift range up to 100 ppm. The structure of the monomer unit of this polymer compound is known, but the fine structure of the polymer is unknown. In this figure, both ¹ H and ¹⁹ F are completely decoupled. In addition, this data is an enlargement of a part of the spectrum observed with a 2048 × 1024 matrix at room temperature. This pulse sequence is an example, and can be applied to all the methods of the two-dimensional H-C hetero reported up to now, and can also be used as the two-dimensional ¹⁹ F- ¹³ C hetero.

Further, in this type of sample, since various ratios of ¹⁹ F and ¹ H exist, and the structural analysis is also extremely complicated, the effect of chemical shift is removed by decoupling, and further, ¹⁹ The magnetization of F or ¹ H is transferred to ¹³ C to improve the measurement sensitivity of ¹³ C,
Various pulse sequences can be considered as a means for assigning signals by changing the phase. For example, as shown in FIG. 6, the pulse sequence shown in FIG. 6A in which magnetization transfer of ¹⁹ F and ¹ H is incorporated into the pulse sequence shown in FIG.
The pulse sequence of FIG. 6 (b), which incorporates broadband decoupling, makes it possible to determine the position of the carbon to which fluorine is attached and the form of its attachment. Further, the method of the present invention can be applied to the measurement of 3D NMR of HFC and 2D and 3D NMR of HPC.

[0016]

INDUSTRIAL APPLICABILITY ¹⁹ F of a fluorine-containing organic compound whose spectrum was difficult to analyze in the measurement by nuclear magnetic resonance
- In ¹³ C, ¹ H- ¹³ C, ¹⁹ F- different nuclide correlation nuclear magnetic resonance, such as ¹ H, along with the full decoupling of ¹⁹ F shows the chemical shifts in a wide range, magnetization transfer to a specific ¹³ C This makes it possible to obtain a spectrum in which the structural analysis of the organic fluorine compound is easy.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of main components of a nuclear magnetic resonance apparatus for carrying out the method of the present invention.

FIG. 2 is a diagram illustrating an arrangement example of coils inside a probe.

FIG. 3 is a time chart showing a measurement sequence using a pulse train for wideband decoupling.

FIG. 4 is a diagram showing F—C cosY { ¹ H} obtained by measuring an organic compound (vinylidene fluoride rubber) containing fluorine and hydrogen using the measurement sequence of FIG. 3.

FIG. 5 is a diagram showing H—C cosY { ¹⁹ F} obtained by measuring an organic compound (vinylidene fluoride rubber) containing fluorine and hydrogen using the measuring sequence of FIG.

FIG. 6 is a diagram showing another measurement sequence.

[Explanation of symbols]

1 ... ¹³ C oscillator, 2 ... ¹⁹ F oscillator, 3 ... ¹ H oscillator, 4 ... ² H oscillator, 5 ... Pulse generator, 6-9 ...
High frequency gate unit, 10 to 13 ... High frequency amplifier, 1
4 ... Probe, 15 ... Inner coil, 16 ... Outer coil,
17 ... ¹³ C observation receiver, 18 ... ¹⁹ F observation receiver, 1
9 ... ¹ H observation receiver, 20 ... Lock signal receiver

Front Page Continuation (72) Inventor Tsukasa Imanari 3-1-2, Musashino, Akishima-shi, Tokyo Inside JEOL Ltd.

Claims (3)

[Claims] 1. A method for measuring a substance containing carbon, fluorine and hydrogen by nuclear magnetic resonance, wherein ¹³ C, ¹⁹ F and ¹ H consisting of two pairs of orthogonal coils and ² H for forming a stable magnetic field are measured. In addition to using a probe capable of measuring, the pulse having a wideband frequency component obtained by changing the frequency and phase of each pulse constituting the pulse train is irradiated to perform decoupling over a wide range and measurement is performed. Of measuring substances containing carbon, fluorine and hydrogen by nuclear magnetic resonance. 2. One of the coils is either ¹⁹ F or ¹ H
It is for ¹³ C and the other coil is either ¹ H or ¹⁹ F
^The method for measuring a substance containing carbon, fluorine and hydrogen by nuclear magnetic resonance according to claim 1, which is for ² H. 3. The method for measuring a substance containing carbon, fluorine and hydrogen by nuclear magnetic resonance according to claim 1, wherein the measurement is performed by performing magnetization transfer from ¹⁹ F or ¹ H to ¹³ C.