JPS5834478B2 - Cationic fence type iron tetraphenylporphyrin and gas adsorbent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an iron tetraphenylporphyrin having four cationic sterically hindered groups standing up on one side of a plane containing a porphyrin ring.

The term "cationic species type" as used herein means having a sterically hindered group as described above.

The present invention also relates to a gas adsorbent made of the above-mentioned iron tetraphenylporphyrin.

Oxygenation and oxidative degradation of iron(1) porphyrin complexes are known to occur according to the following equation.

Oxygenation reaction (in each of the above formulas, porphyrin is omitted, and B is an axial ligand such as imidazole or pyridine).

In the Journal of the American Chemical Society, Vol. 97, p. 1427 (1973), Coleman et al. (called porphyrins).

This picket fence porphyrin has a bulky steric hindrance group on one side of the plane containing the porphyrin ring, which prevents the ligands coordinating to the axial coordinate site from entering, but allows oxygen molecules to freely enter the space (oxygen binding pocket). ) is constructed, and the dimerization oxidation of the formula (3) is prevented.

Further, by carrying out the oxygenation in an organic aprotic solvent such as benzene, single molecule oxidation due to attack by protons shown in the above formula (5) is prevented.

Under these conditions, picket fence porphyrins are capable of reversible oxygen adsorption and desorption.

However, picket fence porphyrin itself is insoluble in water, and if even a trace amount of water is present in the oxygenation system, it undergoes oxidation of one molecule as shown in formula (5) above, rapidly reducing its oxygen adsorption and desorption ability. to lose.

The present inventors studied iron (river) porphyrins that can reversibly adsorb and desorb oxygen in water, and found that such iron porphyrins (1) are themselves water-soluble, and (2) have a structure that prevents attack by protons. This invention was completed based on the knowledge that the following conditions are necessary: (3) being able to prevent dimerization oxidation as well.

That is, the iron porphyrin of the present invention is a cationic fence-type iron tetraphenylporphyrin represented by the general formula (wherein, each R is a plane group containing a porphyrin ring, and "is, independently, a methyl group or an ethyl group)". be.

The cationic fence type iron tetraphenylporphyrin of the present invention has a bulky steric hindrance group R on one side of the plane containing the porphyrin ring, that is, it can prevent dimerization and oxidation like the picket fence porphyrin described above.

Furthermore, since the sterically hindered group R is cationic, it can prevent protons from entering the oxygen binding pocket due to electrostatic repulsion, and it itself becomes water-soluble.

Due to these properties, the cationic fence type iron tetraphenylporphyrin of the present invention reversibly adsorbs and desorbs oxygen in the form of an aqueous solution.

Note that it is most preferable that the porphyrin ring and the cation moiety are bonded based on the hardness of the steric hindrance group and the oxygen bonding pocket.

In order to produce the cationic fence-type iron tetraphenylporphyrin of the present invention, first, an aqueous solution of bromoacetic acid is added to an aqueous solution of a secondary amine represented by the formula (R') 2NH (where R is as described above). dripping,
Make it react.

At this time, NaOH is added in an amount equivalent to about 50 times that of bromoacetic acid in order to prevent the amide generation reaction.

After the reaction is completed, excess secondary amine is removed, neutralized, and triethylamine, ethyl chloroformate and α・α・α・α-
Men [Tetra (orthoaminophenylporphyrin)]
to react with P-(NHCOCH2N(R')2)4(
Here, a tetraphenylporphyrin ring is obtained.

This is purified using a silica gel column. Then, P+NH
-CO-CH2N(R')2]4 was treated with FeBr2 in DMF under an inert atmosphere (e.g. nitrogen) to introduce iron and purified on a basic alumina column to form Fe-IP (NH-CO -CH2N(R')2]4Br
get.

This is reacted with R'Br in aqueous DMF to quaternize the amino group, and the desired cationic fence-type iron tetraphenylporphyrin of the present invention obtained as described above has an axial orientation opposite to the sterically hindered group. By coordinating a ligand (axial ligand) to the position, the ability to adsorb and desorb gases such as oxygen and carbon oxide becomes excellent.

As the axial ligand, a nitrogen-containing compound is used, and this may be either a low-molecular one or a high-molecular one. Examples of low-molecular axial ligands include imidazole and its derivatives, such as imidazole and its derivatives. N-ethylimidazole, pyridine and derivatives thereof such as 4-methylpyridine.

Further, examples of polymeric axial ligands include a copolymer of N-vinylimidazole and vinylpyrrolidone, a copolymer of 4-vinylpyridine and vinylpyrrolidone, and the like.

Usually, it is desirable to add the axial ligand in an amount of 1 to 100 times, preferably 2 to 5 times, equivalent to the cationic fence type iron tetraphenylporphyrin.

In addition, when a polymer compound such as the one mentioned above is used as an axial ligand, its effect increases the water solubility of the cationic fence type iron tetraphenylporphyrin, and it is dispersed and fixed in the polymer chain, so that gases (particularly oxygen ) adsorption/desorption ability is improved.

The gas adsorbent having the above structure has an excellent effect of reversibly adsorbing and desorbing gases such as oxygen and carbon oxide in water and at room temperature.

Based on the above-mentioned properties, the compound of the present invention can be used as an oxygen carrier, a cocatalyst in oxygenation reactions, and a cocatalyst for fuel cells, and since it adsorbs and desorbs oxygen in water, it can be used as a material for artificial blood. It is promising as

Hereinafter, this invention will be explained in more detail with reference to Examples.

Example 1 (A) NaOH21,6? in 50 ml of a 40% aqueous solution of dimethylamine. Dissolve 1.5 bromoacetic acid in this
A solution of 1 dissolved in about 30 ml of water was gradually added dropwise while stirring.

After the dropwise addition was completed, the temperature was raised to 60°C and the reaction was continued for about 5 hours.

Next, the solvent was distilled off under reduced pressure, and at the same time, excess dimethylamine was removed.

Water was added to this to form an aqueous solution, which was then neutralized with diluted hydrochloric acid, and the solvent was distilled off under reduced pressure to dryness.

The product was extracted five times with methanol and twice with ethanol to obtain the desired product ■C1○ (.

H3)2NH-6H2oooH (hereinafter referred to as product (I)) was obtained.

The yield was 0.811P, and the yield was 41%.

The NMR spectrum (ppm) of product (I) is shown below.

(B) Product (i) 0.811S' in DMF about 1o
After dissolving in WLl and cooling to below 0°C, 1.62 rfLl of triethylamine and 1.1 ml of ethyl chloroformate were added while stirring, and the mixture was reacted for about 1 hour.

In addition to this, α・α・α・α-meso[tetra (orthoaminophenylporphyrin)] (hereinafter referred to as α・α・
0.123P (referred to as α・α-H2TamPP) was added, and the mixture was allowed to react at 0°C or below for 2 hours and then at room temperature for about 1 hour.

After the solvent was distilled off under reduced pressure, chloroform was added to form a solution, which was filtered.

The filtrate was concentrated under reduced pressure and applied to a silica gel column (C-30013
CrfLφ×3ocrrL), developed with chloroform, and mixed the developing solution with chloroform/methanol (10=1
．． The mixture was sequentially changed to a 5:1.2:1 mixture, and finally developed with methanol alone.

The part adsorbed on the column at the origin was taken out, extracted with a 50:1 mixture of methanol/hydrobromide, and neutralized with NH and OH.

After drying the solvent under reduced pressure, it was extracted with methanol 5 times, further extracted with dichloromethane, and the solvent was dried under reduced pressure to obtain the desired product IP+NHCOCH2N(CH3)2)4 (I
As mentioned above, P is 0.05 (hereinafter referred to as product (river))
P (yield 27%) was obtained.

The NMR spectrum (ppm) of this product (river) was as follows (in CDC13):

Pyrrole-H: 8.8 (8H); Amide N-H: 8.7
(4H) Phenyl group-H: s, o-7,3 (16H); Pyrrole-H 2.6 (2H) Methylene-CH2-: 3.8 (8H); Methyl N-
CH3: 30 (24H) (q Product (river) 50rn9 was dissolved in DMF5o1rLl, about 10 equivalents of FeBr2 was added while blowing nitrogen, and the mixture was reacted at 100°C for 5 hours.

After the reaction was completed, the solvent was dried under reduced pressure, and chloroborm was added to form a concentrated solution.

Add this to a basic alumina column (2crfLφ×8Crr
L) and eluted with a 2:1 chloroborum/methanol mixture, and the effluent was recrystallized from a dichloromethane/n-hebutane mixture to give the desired product Fe1P-(-NH-COCH2N(CH3)2.Br
] 4 (hereinafter referred to as product (In)) 38■ (yield 70
%) was obtained.

(0 product (I[I) 30μ is dissolved in DMF30−,
1.5 ml of water and about 6-7 equivalents of methyl bromide (based on the complex) were added and reacted for 12 hours at 30-40'C.

The product was recrystallized from a methanol/ether mixture to give the final desired product:
27 mg of Br (yield 83%) was obtained.

The NMR spectrum (ppm) of this product was as follows (in D20):

Pyrrole-H: 77-83 (8H); Amide NH:
9 (4H) Phenyl group-H: 6.8-9 (16H); Methylene-CH2-: 4.1 (8H) Methyl N-CH3: 3.4 (36H) Note that Br ion is 5% of the complex It was confirmed by the Nerhardt method that an equivalent amount was present.

Example 2 In the same manner as in Example 1, a compound of formula (A) in which R' is an ethyl group was produced as follows.

In Example 1 (A), a 35% aqueous solution of diethylamine (6oTLl) was used instead of the aqueous dimethylamine solution to obtain (C2H,)2NHCH2COOH (hereinafter referred to as product (rV)) (yield 48%). .

The NMR spectrum (ppm) of product (IV) is shown below.

In Example 1(B), product (IV) 0.92S' was used instead of product (I), and triethylamine was added to 1 ml of 1.5r1111 ethyl chloroformate and α
・Carry out the reaction with 0.12r of 2TamPP in α・α・α- to produce tp(NHcocn: 2N (C2H5)
2) 4 (hereinafter referred to as product (V)) was obtained (yield 1
5%).

The NMR spectrum (ppm) of this product (V) was as follows (in CDC13).

Pyrrole-H: 8.9 (8H); Amide-H: 8.
7(4H) Phenyl group-H: 8.1-7-3 (16H); Pyrrole-H-2,7(2H) Methylene-CH,2-: 3.9 (8H); Ethyl-CH2-: 3 .3 (16H) Ethyl-CH3: 1.8 (24H) Fe was introduced into the product (V) in the same manner as in Example 1 (C) to obtain FeP+NHCOCH2N(C2H5))4Br (hereinafter referred to as the product (Vl ) was obtained (yield 70%).

Finally, a similar reaction was carried out using ethyl bromide in place of methyl furomide in Example 1 (Q).
e Fe P(-NHCOCH2N(C2H5) 3 B
r, :14B r was obtained (yield 8o%).

The NMR spectrum of this product (99ml) was as follows (D201):

Pyrrole-H: 75-85 (8H); Amide NH:
8.9 (4H) Phenyl group -H: 7-9.1 (16H); Methylene CH2-: 4.2 (8H) Ethyl CH2: 3.7 (24H): Ethyl C
H3: 2.1 (36H) In addition, 5 equivalents of Br based on the complex was determined by the Nerhardt method.
The presence of ions was confirmed.

Example 3 The final product obtained in Example 1 was dissolved in water (phosphate buffer pH 7.0) at a concentration of 3 x 10-'' mol/l, to which was added 1.5 x 10-'' of N-ethylimidazole. It was dissolved at a concentration of 2 mol/l.

After blowing nitrogen gas into this aqueous solution for about 1 hour, it was charged into the sphere of a spectroscopic cell equipped with a Thunberg tube.

A very small amount of Na2S2O4 was placed in the cell part.

The bulb is frozen and degassed three times using a dry ice-methanol system, and the aqueous solution is transferred to the cell to obtain a reduced complex.

When this was observed with an ultraviolet-visible spectrophotometer, a Fe (river) type spectrum was obtained, which had a thick absorption at 537 nm.

When oxygen was blown into this aqueous solution and stirred, a spectrum of an oxygenated chain having an absorption maximum of 541 nm was obtained.

After leaving this in an oxygen atmosphere for several minutes and then freezing and degassing, the Fe(II) state returned to almost the same absorption spectrum.

Note that the measurements were performed at room temperature.

This spectral change is shown in the accompanying drawing.

In the figure, curve a is for the Fe(1) state, curve 2 is for the oxygenated state, and curve C is for the state after being left in the oxygenated state for several minutes and then frozen and degassed.

Example 4 Copolymer of KN-vinylimidazole and vinylpyrrolidone (molecular weight 38,000, imidazole unit 41 mol%, hereinafter P) was used instead of N-ethylimidazole as the axial ligand.
5 to 1 of the complex with imidazole unit (referred to as IPo)
The oxygenation reaction was examined in the same manner as in Example 3 except that 0 times equivalent was used.

First, a spectrum of Fe(Il) type having an absorption maximum at 538 nm was obtained, and after oxygen injection, a spectrum of an oxygenated complex having an absorption maximum at 542n7W was obtained.

When the oxygenated complex was left in an oxygen atmosphere for about 30 minutes and nitrogen was inhaled, the absorption spectrum returned to almost the same as that of the F, e (kawa) type.

The spectral changes were similar to the attached figures.

Example 5 In the same manner as in Example 3, the oxygenation reaction of the final product obtained in Example 2 was investigated.

However, as the axial ligand, PIPo of Example 4 was used in imidazole units in an amount equivalent to five times that of the complex.

First, a Fe (river) type spectrum with a thick absorption at 537 nm was obtained, and when brought into contact with oxygen, a spectrum of an oxygenated complex with a thick absorption at 541 nm was obtained.

When the oxygenated complex was left in an oxygen atmosphere for 30 minutes and nitrogen was blown into it, the absorption spectrum returned to almost the same as that of the Fe (river) type.

In addition, when the same operation as above was performed except that N-ethylimidazole was used as the axial ligand, 537n
A spectrum of the Fe (river) type having an absorption maximum at 545 nm and a spectrum of an oxygenated complex having an absorption maximum at 545 nm were obtained.

The above respective spectral changes were similar to those shown in the attached drawings.

Example 6 A Fe(II) type complex was obtained in the same manner as in Example 3, and CO gas was blown into it for 10 seconds.

The thickest visible absorption spectrum is 537 nm (
from 540nm (absorbance approx. 0.43) to 540nm (absorbance approx. 0.
．． 54), and formation of an Fe(■)/CO complex was confirmed.

This state did not change even after observation for one week under a CO atmosphere and one day under air. However, when the freezing and degassing operation was repeated three times under a high vacuum of about 100-77 flfflH, the original Fe(II) ) 100% returned to the mold.

This material was further blown with CO for 10 seconds, and the same degassing operation as above was repeated 5 times.
A spectrum with an absorbance of about 0.42 at 37 nm was obtained, confirming that it had returned to its original Fe(II) form.

Example 7 The same procedure as in Example 4 was carried out to obtain a Fe (river) complex.

When CO gas was blown into this for 10 seconds, the maximum visible absorption spectrum changed from 538 nm (absorbance approximately 0.44) for the Fe (kawa) type to 540.5 nm (absorbance approximately 0.44).
54), and Fe(■)・c.

Complex formation was confirmed.

Thereafter, as in Example 5, the operation of degassing → CO blowing → degassing was repeated five times, and as a result, the visible absorption
A spectrum with an absorbance of 0.427 was obtained at 38 nm, and it was confirmed that at least 98% of the product had returned to its original Fe(II) form.

Example 8 The same procedure as in Example 3 was used except that pyridine dissolved at a concentration of 1.5·10-2 mol/l was used as the axial ligand to obtain a visible absorption spectrum with a maximum of 535 nm (absorbance of approximately 0).
．． A Fe (kawa) complex solution showing 41) was obtained.

When oxygen was blown into the mixture and stirred, the spectrum was measured, and the absorption changed to 539 nm and absorbance to 0.36, confirming the formation of an oxygenated complex.

Hold this state for about 5 minutes, freeze and degas, and the maximum wavelength will be 535 nm.
It was confirmed that the absorbance returned to 0.35 (δ) and returned to the original Fe(II) state.

Furthermore, when high-purity nitrogen gas or an inert gas such as argon or helium was blown into the oxygen-saturated aqueous solution while stirring, the original Fe(II) state was similarly restored.

Example 9 The same procedure as in Example 7 was carried out except that CO was used instead of oxygen. confirmed.

When this aqueous solution was frozen and degassed under a high vacuum of 10-7n0-7n, the maximum absorption was 5351m, and the absorbance was 0.
It returned to the original Fe (river) state of 36.

Example 10 As an axial ligand, poly(4-vinylpyridine, vinylpyrrolidone) obtained by radical copolymerization by a conventional method (molecular weight 23000, 4-vinylpyridine unit 15 mol%)
An aqueous solution of Fe (kawa) complex (visible absorption spectrum maximum 53
4 nm, absorbance 0.40).

When oxygen was blown into this and stirred, a new spectrum with an absorption maximum of 539 nm and an absorbance of 0.32 was immediately observed, confirming the formation of an oxygen complex.

After being left for 5 minutes, the sample was frozen and degassed, and the spectrum was measured again to obtain an absorption maximum of 534 nm and an absorbance of 0.40, confirming that it had returned to its original Fe(kawa) complex.

Example 11 A CO complex aqueous solution was obtained in the same manner as in Example 1o except that CO was used instead of oxygen.

The visible absorption spectrum has a maximum thickness of 538 nm and an absorbance of 0.48°. This was frozen and degassed three times at 10-7 nmHg, and the spectrum was measured to confirm that it had returned to the original Fe complex with an absorption maximum of 534 nm and an absorbance of 0.40. confirmed.

[Brief explanation of drawings]

The attached drawing is a diagram of changes in visible absorption spectrum caused by contacting the cationic fence-type iron tetraphenylporphyrin of the present invention with oxygen.

Claims (1)

[Scope of Claims] 1. A cationic fence-type iron tetraphenylporphyrin represented by the general formula (wherein each R is a plane group containing a porphyrin ring, and " is, independently, a methyl group or an ethyl group) or the other of said planes. A complex thereof in which a ligand is coordinated to the side axial coordinate site. 2. A patent claim in which the ligand is imidazole or a derivative thereof, pyridine or a derivative thereof, or a polymeric ligand having an imidazole nucleus or a pyridine nucleus. The cationic fence type iron tetraphenylporphyrin or the complex thereof according to item 1. A gas adsorbent for oxygen gas and carbon monoxide gas consisting of a complex in which a ligand is coordinated to the axial coordinate site on the other side of 4. The ligand is imidazole or its derivative, pyridine or its derivative or imidazole. 5. The gas adsorbent according to claim 3, which is a polymeric ligand having a nucleus or a pyridine nucleus. 5. The gas adsorbent according to claim 3 or 4, which is in the form of an aqueous solution.