DE2645079A1 - Reversible oxygen carriers used as blood substitutes - comprise a complex of a tetra:dentate polymer with a transition metal - Google Patents

Abstract

A soluble polymeric metal complex comprises a transition Gp. IB, VIIB or VIIIB metal ion bonded covalently to a tetra-dentate polymer ligand. The metal ion has >=1 other ligand bonded axially to it and the polymer may be natural or (semi)-synthetic. Pref. polymers are water soluble having functional NH2, OH or carboxy gps. e.g. polyethers e.g. polyethylene glycol, dextrans, chemically modified proteins, polysaccharides, polyamino acids, PVA, PVP, polyurethanes, poly(meth)acrylic acid, polyethylene imine etc. The complexes can be used as reversible oxygen carriers to improve the oxygen concn. of solns. They may be used as blood substitute, in fuel cells, oxidation reactions as catalysts and in oxygen production.

Description

Polymeric oxygen carriers and process for their production

In mammals, hemoglobin serves as a reversible oxygen carrier and myoglobin. In hemoglobin is the low molecular tetradentate porphyrin as Iron complex (heme) fixed to the protein globin, with the imidazole nitrogen being a Histidine residue is bound as an axial ligand to the heme iron complex. The reversible Oxygenation of a low-molecular porphyrin metal complex with a low-molecular one axial, fifth ligand has so far not been successful under physiological conditions (see J.P.

Collman et al. j. At the. Chem. Soc. 97: 1427 (1975); J.E. Baldwin et al. J. Huff, J. Am. Chem. Soc. 96: 5600 (1974).

-There has been no shortage of attempts to imitate the globin zp by instead of protein, synthetic polymers, e.g. from pyridine or imidazole units are constructed as axial 5th ligands on low molecular weight metal-porphyrin complexes be bound in a complex manner. But even these connections do not form any under physiological Conditions reversible oxygenable complexes and an oxo complex can at best as an intermediate stage of an irreversible oxidation (cf.e.g. J.H. Wang, A.

Fakahara and E.B. Fleischer J. Am. Soc. 80: 1109 (1958); E. Tsuchida, K. Honda and H. Sata, Inorg. Chem. 15, 352 (1976).

It has now been found that reversible under physiological conditions oxygenatable complexes are obtained when the tetradentate porphyrin ligand and preferably also the axial 5th ligand are combined in a synthetic polymer, thus at least 4 or 5 ligands from the polymer are available for complex formation stand. According to the invention, several can covalently in one ol of a polymer bound "active centers" each with a tetradentate porphyrin ligand and one further 5th axial ligands may be included.

Water-soluble polymers with functional ones are suitable as base polymers Groups such as amino, hydroxy or carboxy groups.

According to the invention, polyethers such as polyethylene glycol (PEG), Dextrans, chemically modified proteins or polysaccharides, polyamino acids, polyvinylpyrrolidone, Polyvinylamine, polyethyleneimine, polyurethanes, polyvinyl alcohol, polyacrylic acids, Polymethacrylic acids or copolymers or polycondensates of these polymers are used will. The tetradentate ligand is attached to the functional groups of the polymer and the axial 5th ligand directly covalently bonded. On the other hand, the functional Groups of these polymers are further changed before the binding of the ligands, for example through the conversion of OH groups of polyethylene glycol to amino groups or bonds of any bi- or multifunctional compounds. So have according to the invention Diamines, diisocyanates, dialkholes, aminocarboxylic acids and peptides for further functionalization proven of base polymers.

Since when using PEG only the two terminal hydroxyl groups available as reactive centers and a higher loading of the soluble Generally desirable carrier has been obtained by polyaddition of diisocyanates and PEG represented a new polymer that is both high molecular weight and polyfunctional is. The diisocyanates used contain an additional functional group.

Synthesis scheme: (n + 1) HO- (CH2CH2O) mH + n OCN-R-NCO x nA nB H [OCH2CH20) m-CO-NH-R-NH-CO)] n (OCH2CH2O) mH X (AB) n For example, PEG (MW 1000) was mixed with 3-nitro-3-azapentane-1,5- diisocyanate implemented. After catalytic reduction, polymers of the following structure were obtained: (MW >>10,000; 1 NH2 group per 1 g PEG1000) The tetradentate ligand and the 5th axial ligand are bound to the polymer, the copolymer or the functionalized polymer via ester, amide, urethane or ether groups. The tetravalent ligand and the 5th axial ligand can be bound to two different or identical functional groups of the polymer, the copolymer or the functionalized polymer.

On the other hand, tetradentate ligand and axial ligand can be used one after the other arranged and thus bound via the same functional groups of the polymer be.

The 5th ligand can also advantageously be covalent via amide or ester bonds be fixed to a side group of the tetradentate ligand.

As tetradentate ligands that are bound to polymers macrocyclic containing 4 nitrogen atoms or 2 nitrogen and 2 oxygen atoms Systems, for example porphyrins, chlorins, phthalocyanines, SAD (salicylaldehyde-ethylene diimines) or their derivatives. These ligands contain alkyl or aryl side chains, with functional groups for fixing to the polymer.

The axial 5th ligands are amines or, preferably, nitrogen-containing Heterocycles such as pyridine and imidazole are used by alkyl or aryl groups are substituted. The heterocycles or their side chains contain functions such as amino, hydroxy, carbonyl or carboxy groups that form a covalent bond to the polymer or tetradentate ligand.

According to the invention, the axial ligand can also have 2 or more functional Groups that can be covalently fixed to both the polymer as a substituted also allow the tetradentate ligands. Amino acids, such as histidine, can be used as such bifunctional ligands.

Metals can be used as the central atom of a polymeric metal complex the groups I B, VII B and VIII, for example Fe, Co, Mn and Cu in their various Valence levels in question. The metal ions can already be attached to the tetradentate ligands be bound or subsequently introduced into the finished polymer complexing agent will. According to conventional methods, complexes are bound by the oxygen bond Metal ions of higher oxidation state with reducing agents in the for oxygenation suitable oxidation state (for example Fe (11 ?, Co (II)) transferred.

After the reducing agent has been separated off, the polymeric complexes are standing available for oxygenation. In the case of the soluble polymers thus represented Metal complexes simplify the removal of low molecular weight by-products by that permselective separation methods such as ultrafiltration and gel chromatography are used can be.

The soluble polymeric metal complexes thus represented can be used anywhere used where the amount of available oxygen in a solution is above normal Oxygen concentration should also be increased. This is for oxygen transport in organisms as a blood substitute, for fuel cells and oxidation reactions of Interest. Also as solid or homogeneous soluble catalysts or for recovery the compounds can be used by oxygen from air.

The following examples are intended to explain the invention without illustrating it limit.

Abbreviations AcOH 'glacial acetic acid API aminopropylimidazole AS amino acid Aspartic acid BOC- tert. Butyloxycarbonyl Bzl Benzyl DCCI dicyclohexylcarbodiimide DiBOC-His N -BOC (Im-BOC) histidine DC-urea dicyclohexylurea DMF dimethylformamide DMSO dimethyl sulfoxide Gly Glycine HOBt 1-Hydroxybenzotriazole i.V. in a vacuum PEG polyethylene glycol (bifunctional) PEG-OMe polyethylene glycol monomethyl ether (monofunctional PEG) PVP poly- (1-vinylpyrrolidinone- (2)) TFA. Trifluoroacetic acid THF tetrahydrofuran PEGx polyethylene glycol (bifunctional) with molecular weight x BOC-Gly-OBt-ester t-butyloxycarbonyl-glycyl-benzotriazolyl ester example 1 Hemin-His-Gly-PEG15000 The polyethylene glycol (PEG; MW 15000, Fluka) in methylene chloride dissolved, precipitated with diethyl ether at OOC, the filtered precipitate with ether washed and dried i.V. (all solvents are dried beforehand and distilled).

1.1 Esterification of PEG15000 with BOC-Glycine 15 g of this PEG (2 mmol functional groups) were dissolved in 150 ml CH2Cl2 and 20 mmol BOC-Gly and 20 mmol DCCI added. It was left to stand at room temperature for one day and from Urea derivative filtered off. It was refluxed for 6 days, the solution was concentrated, the product crystallized with diethyl ether, stirred for 10 minutes at 0 ° C and on sucked off a glass frit. The product was taken up in about 50 ml of methylene chloride, precipitated with ether, suctioned off and dried to constant weight.

Yield 15.0g.

1.2 Cleavage of the BOC protective group The BOC-Gly-PEG was in 150 ml Let CH2Cl2 / TFA (1: 1) stand for 20 minutes at room temperature, to about 30-50 ml concentrated, precipitated with ether, reprecipitated from CH2Cl2 / ether as above and dried. Yield 14.8 g of TFA.H-Gly-PEG. Loading (AS analysis): 0.13 mmol / g = 100% of theory. Th.

1.3 Coupling with histidine 6 g of H-Gly-PEG15000 were dissolved in 30 ml of CH2Cl2 dissolved and neutralized with N-methylmorpholine. 3 mmol of Di-BOC-His were added to this solution added to 20 ml of DMF and 3 mmol of DCCI.

After one hour the urea derivative was filtered off, the filtrate concentrated on a rotary evaporator precipitated with ether, filtered off, in absolute ethanol under warming taken up, left to stand at -1O0C for two hours and centrifuged off.

Yield 4.4 g of DiBOC-His-Gly-PEG15000.

1.4 Di-BOC cleavage from His Analog procedure under 2). loading with histidine: 93%.

1.5 Coupling with hemin 4.4 g of TFA.H-His-Gly-PEG15000 were in 40 ml CH2Cl2 added (approx. 0.6 mmol NH2 groups) and adjusted to pH 7 with N-methylmorpholine brought. Then 1 mmol hemin (= 2 mmol COOH groups) and 2 mmol DCCI were added. It was stirred for 48 hours at room temperature and filtered off with suction from the urea derivative The filtrate was brought to dryness and the residue was dissolved in methyl ethyl ketone / methanol with gentle warming (1: 1) dissolved and precipitated while cooling with ether. After redissolving in methyl ethyl ketone / methanol and ether was used to remove the hemin excess.

Example 2 2.1 0.5 mmoles of 3- (1-imidazolyl) propylamine dihydrochloride (can be prepared according to J. Heterocycl. Chem. 4 (1967), 633) was dissolved in ethanol and'mit Methylmorpholine adjusted to pH 7.

2.2 0.85 g (0.05 mmol) of the hemin-His-Gly-PEG15000 obtained according to Example 1 were dissolved in 5 ml of CH2Cl2 and, with ice cooling, 6.8 mg (0.05 mmol) of HPBt in 8 ml THF and 10.3 mg (0.05 mmol) DCCI in 2 ml CH2Cl2 added. After stirring for 10 minutes at 0 ° C., the solution was left to stand at room temperature for 20 minutes. Then became the precipitated TLC urea is filtered off and the filtrate is combined with the solution from 2.1.

After concentration to 10 ml, the mixture was stirred at pH 7 for 1 day. The solution was evaporated to dryness i.V. and the residue in so much warm, absolute ethanol added that the solution was about 5-10% polymer product contained. After 24 hours at -5 ° C., the polymer had crystallized out, whereupon it was 20 minutes centrifuged at 10,000 rpm, the supernatant solution decanted and the precipitate was washed with cold ethanol. Crystallization from ethanol was done twice repeated. Finally, the polymeric product was taken up again in ethanol and precipitated with ether as described.

Example 3 Representation of (PEG) polyfunctional 1 polyfunctional His Haemin 3.1 Polyfunctional polyethylene glycol (polyamine) In a three-necked flask equipped with a stirrer and thermometer, 5 ml of toluene were added to 10 g of purified PEG, MW 1000 (10 mM) and heated to 80.degree. 0.3 ml of tin laurate was added as a catalyst to the stirred solution and a solution of 10 mM diisocyanate in 3 ml of toluene was slowly added dropwise with vigorous stirring. After about 10 minutes, a further 5 ml of toluene were added to the viscous solution and the mixture was stirred for two hours at 80 ° C. After the solvent had been distilled off in vacuo, the residue was extracted twice with ether and taken up in ethanol to form a 10% solution, with AcOH adjusted to pH 4, added Raney nickel and hydrogenated at 100 atm. After the H2 uptake was complete, the catalyst was filtered off, enough water was added to the clear solution that a 70% solution was formed, and with a Diaflo UM-10 membrane up to ultrafiltered to constant weight in order to remove low molecular weight fractions After distilling off the water and drying the retendate, 10.2 g (= 85% of theory) of polyamine were obtained.

3.2 Coupling of the polyamine with histidine 2 g as shown in 3.1 Polymers with approx. 2 mmol NH2 groups were dissolved in 20 ml CH2Cl2 / DMSO (1: 3) and neutralized with N-methylmorpholine. 2 mM BOC-His were in 30 ml DMF / DMSO (1: 3) dissolved and mixed with 2 mM HOBt and 2 mM DCCI. After 30 minutes at 20 "C it became this solution was added to the polymer solution and stirred overnight. The solution was concentrated to about 20 ml and the polymer as an oily product by the dropwise addition of ether failed. The supernatant was decanted off.

3.3 Cleavage of the BOC protective group The product obtained under 3.2 was dissolved in 20 ml TFA / CH2Cl2 (1: 1) at room temperature, after 30 minutes the solution concentrated, the polymeric product precipitated with ether and the supernatant decanted off.

3.4 Coupling with hemin 1.3 g (2 mM) hemin were dissolved in 50 ml of CH2Cl2 and 5 ml of DMF dissolved. After adding 2 mM DCCI, the mixture was stirred at room temperature for 2 hours. It was then filtered and the solution to the polymer product obtained under 3.3, which was dissolved in 30 ml of DMSO and 20 ml of CH2Cl2, added. After 3 days it was filtered off and the solvent evaporated at 600C i.V. The residue was with approx. 50 ml H20 added. After filtering off insoluble components, the The filtrate is concentrated in the ultrafiltration cell (membrane UM 10) and dialyzed Remnants of reaction components removed. After that, the water was freeze-dried removed.

Hemin load: 100%. Yield: 1.3 g.

Example 4 polyvinylpyrrolidinone hemin 4.1 hydrolysis of poly- (1-vinylpyrrolidinone- (2)), (PVP), MG 40,000 according to Hoppe S.Z. physiol. Chem. 354, 1659 (1973) After hydrolysis was acidified to pH 5 and ultrafiltered. The solvent was evaporated i.V., the residue was taken up in dimethylformamide and the solution was added dropwise to ether. The precipitate was filtered off and dried over P205 in vacuo.

4.2 Determination of the degree of hydrolysis The degree of hydrolysis of product 4.1 was determined by titration of the secondary amino groups. It was 15%, i.e.

1 g of PVP contains 1.25 mM functional groups.

4.3 Blocking of the secondary amino groups by acetylation 5 g of the PVP produced in this way were dissolved in 30 ml of CH2Cl2, the solution with N-methylmorpholine adjusted to pH 8 and treated with 1 g of acetic anhydride (about 10 mM). the Solution was refluxed for one hour, concentrated to 20 ml and reduced at OOC vigorous stirring in 300 ml of ether added dropwise.

The precipitate was filtered off with suction and dried.

4.4 Activation of the carboxyl groups of the partially hydrolyzed PVP 5 g of the product obtained under 3.4 (6.25 mM) were dissolved in 30 ml of CH2Cl2 (A). 6.25 mM HOBt were dissolved in 10 ml DMF in a separate vessel (B). B was added to A. 6.25 mM DCCI were added, the mixture was stirred at 40 ° C. for 4 hours, the precipitated DC urea filtered off, the solution concentrated to about 20 ml and the polymer product precipitated by adding dropwise to 300 ml of ether. Yield: 4.7 g.

4.5 Reaction with ethylenediamine 4.7 g of the product obtained under 4.4 4 are dissolved in 30 ml of CH2Cl2 and at OOC with 5 ml of ethylenediamine (25-fold excess) offset. After a reaction time of 4 hours at room temperature, the solution is concentrated and the polymeric compound precipitated with ether as described. The product will again taken up in CH2Cl2 and precipitated again.

Yield: 4.0 g.

4.6 Coupling of hemin to the product obtained under 4.5 4 g des The product obtained under 4.5 (5 mM amino groups) is dissolved in 20 ml of CH2Cl2 and adjusted to pH 7 with morpholine (A).

4 mM hemin are dissolved in 10 ml dimethylformamide in a separate vessel, at OOC, 4 mM HOBt and 4 mM DCCI were added and the mixture was left to stand for 2 hours at room temperature (activated), (B.

Solution B then becomes a solution with the TLC urea being filtered off Am given and stirred for 16 hours at O; OC.

The solution is concentrated to remove excess hemin and the polymer precipitated with ether as described.

The filtered product is in a mixture of ethyl methyl ketone and ethanol (2: 1) taken up and precipitated with ether. After 2 hours at -100C the PVP hemin is filtered off and dried.

Yield: 3 g.

Hamin loading: 57 &. %.

Example 5 5.1 Esterification of polyethylene glycol monomethyl ether of molecular weight 10,000 (monofunctional PEG, MeO-PEG) with glycine BOC-Gly-PEG-OMe 30 mM (5.25 g) BOC-Gly and 30 mM (4.1 g) HOBt are at 30 mM DCCI in 50 ml THF / CH2Cl2 (1: 1) at 0 ° C for 15 minutes (preactivated). The TLC urea formed is filtered off and the filtrate is added to a solution of 50 g of MeO-PEG10000 (5 mM) in methylene chloride. The solution is concentrated and stirred at 40 ° C. for 24 hours. Then again 30 mM BOC-Gly-OBt-ester are added to the reaction solution and the mixture is stirred at 40 ° C. for a further 20 hours.

The solution is then treated with diethyl ether until it begins to become slightly cloudy added and on the rotary evaporator in an air bath by removing small amounts of ether cooled, the ester crystallizing out in a readily filterable manner. After approx.

The solution is filtered and left to stand at OOC for 30-60 minutes the precipitate washed with ether. The esterified polymer is through two times Reprecipitation purified from methanol.

5.2 Cleavage of the ol amino protective group 20.3 g of BOC-PEG-OMe become dissolved in 250 ml of 1.2 N HCl / glacial acetic acid at room temperature and stirred for 20 minutes. Of the Hydrogen chloride is then drawn off quickly on a rotary evaporator and the solution constricted. The viscous solution is abs in 200 ml. Ethanol added and the polymer product precipitated with ether. After standing overnight in the freezer, the precipitate becomes filtered off, collected on a glass frit and washed. Then the The polymer product was reprecipitated twice more from ethanol and the precipitate was then dried.

Loading with gycin according to amino acid analysis: 72% yield: 19.5 g.

5.3 Coupling with BOC- ~ -aspartic acid-B-benzyl ester 10.1 g HCl.Gly-PEG-OMe are dissolved in 70 ml of CH2Cl2 and neutralized with morpholine.

2.6 BOC-L-Asp (OBzl) -OH (8 mM) are dissolved in 20 ml of CH2Cl2 and cooled to OOC. A solution of 0.8 g DCCI (4 mM) in 10 ml CH2Cl2, which was also cooled to OOC, given. The solution is kept in the freezer for 15 minutes, then left to stand for 10 minutes at room temperature. While filtering off the precipitated DC urea, the filtrate is added directly to the Gly-PEG-OMe solution. The precipitation is washed with CH2Cl2. The solution is adjusted to pH 7 and concentrated. After 1 hour, the pH is checked again and, if necessary, neutralized with morpholine. The isolation (precipitation with ether) and purification of the product is as described performed.

Coupling time: 2.5 hours. Yield: 8.3 g conversion control potentiometrically or fluorimetrically with phthalaldehyde: 99% conversion.

5.4 BOC elimination analogously to 5.2 Yield: 8.1 g.

5.5 Coupling with DiBOC-Histidine Q To a solution of 8 g of the after 5.4 obtained neutralized peptide PEG ester in 50 ml CH2Cl2 is the preactivated Di-BOC-His added (5.6 g DiBOC-His = 16 mM + 1.6 g DCCI = 8 mM).

Response time: 5.5 hours. Conversion: 81% after titration.

It was preactivated with 3.8 g (10.7 mM) Di-BOC-His (preactivated with 1.1 g (5.35 mM) DCCI) post-coupled. Isolation and purification of the product as described.

Coupling time: 15 hours Conversion: 90 t.

Ratio Gly: Asp: His according to AS analysis = 1.2: 1: 1 (based on on His) 5.6 Splitting off of BOC protective groups analogous to 5.2.

Yield: 5.9 g 5.7 coupling of H + His-Asp-Gly-PEG-OMe OBzl of hematoporphyrin 2.1 g of the polymer obtained according to 5.6 (= 0.1 mM His after loading test) are in 30 ml of abs. Dissolved CH2Cl2 and 3 ml DMF and neutralized with N-methylmorpholine.

Then 0.1 mM hematoporphyrin, dissolved in 2 ml DMF, and 0.2 mM DCCI (413 mg), dissolved in a little CH2Cl2, added to the polymer solution. After about 1 hour Stirring at room temperature is adjusted to pH 7 with N-methylmorpholine, the solution Concentrated on a rotary evaporator to approx. 25 ml and stirred for 14 hours.

After filtering off the TLC urea, the solvent is evaporated off i.V., the residue was taken up in 50 ml of warm ethanol and the polymer with diethyl ether failed again. After two further cleaning steps (reprecipitation from ethanol) the product is dried.

Yield ~ 1.75g.

5.8 Esterification of the hydroxyl groups of the hematoporphyrin with BOC-Gly 1.75 g (0.16 mM polymer) of product 5.7 are dissolved in 30 ml of CH2Cl2. Separately 3.2 mM BOC-Gly (0.56 g) are dissolved in 10 ml of 'CH2Cl2 and a solution of 3.2 Added mM HOBt (432 mg) in 5 ml of THF. 3.2 mM DCCI (66 mg) are added to this solution added in 10 ml of CH2Cl2. After stirring for 30 minutes at room temperature, it is filtered off and the filtrate is added to the polymer solution. The reaction solution is on 25th ml, after having been adjusted to pH 7 with 0.5 ml of pyridine and morpholine became. After stirring for 1 hour at room temperature, the mixture is refluxed for 15 hours cooked.

The solvent is then evaporated off in vacuo. The residue will taken up in 30 ml of warm ethanol and precipitated the polymer product with ether. After three reprecipitations from ethanol, the product is dried.

Yield: 1.57 g.

5.9 Coupling with aminopropylimidazole The following solutions are prepared: a) 1.57 g (0.14 mM) of product 5.8 are dissolved in 20 ml of CH2Cl2.

b) 3.5 mM 3- (1-imidazolyl) propylamine dihydrochloride are added in 15 ml abs. Dissolved ethanol and neutralized with morpholine. After that the solution will come up 3-5 ml concentrated.

c) 18.7 mg of HOBt are dissolved in 1 ml of THF.

d) 28.5 mg DCCI are dissolved in a few ml CH2Cl2.

Solution c) is added to a), then solution d) and finally b) added within a minute. The mixture is then stirred for 16 hours at room temperature. After filtering off the precipitate, which is washed with CH2Cl2, the The filtrate was concentrated to dryness. The residue is in 25 ml of abs. Dissolved ethanol and the polymer product crystallizes out by cooling the solution to 20C (24 hours), centrifuged off, the supernatant solution discarded and the precipitate with cold Washed ethanol The residue is redissolved in approx. 15 ml of ethanol in the heat, the polymer precipitates out of this solution with ether, filtered off, the precipitate washed with ether and dried.

The cleaning step is repeated twice.

5.10 Removal of protective groups with HF (BOC and benzyl group) 1.5 g dry product from 5.9 with 1.5 g of anisole in a 25 ml polypropylene bottle filled, which is screwed with an attachment for introducing HF. Be at OOC 12-15 ml HF condensed and the mixture stirred for 30 minutes at 40C. The hydrogen fluoride is blown off with nitrogen at 300C. The last remnants of HF and anisole are removed in a desiccator charged with KOH under a high vacuum. After that, the Substance dissolved in 20 ml of DMF with heating, the polymeric product precipitated with ether and cleaned and dried as usual.

Yield: 1.33 g.

5.11 cyclization 1.33 g of product from 5.10 are dissolved in 40 ml of CH2Cl2 dissolved -and neutralized. 70 μM HOBt in 5 ml THF are added to this solution, then it is diluted to 90 ml with CH2Cl2.

After cooling to OOC, the reaction solution is cooled to OOC with a Solution of 70 μM DCCI in 10 ml CH2C 12 added.

After 1 hour at OOC, the mixture is stirred for three days at room temperature. The solution is then concentrated to 50 ml, filtered and the cyclized product precipitated with ether. The precipitate is taken up in DMF and the polymer product Reprecipitated with ether, filtered off and dried.

Yield: 1.25 g Gly: Asp: His ratio according to AS analysis = 2.9 : 1.2: 1 (based on His).

Example 6 Incorporation of metal into the polymeric hemin ligands 6.1 Incorporation of cobalt in polymer obtained according to example 5: 0.2 g polymer product (ru 0.01 mM porphyrin derivative) are dissolved in 20 ml of methanol with heating and heated to boiling. Within 5 minutes, 0.2 mM Co (II) acetate, which are dissolved in 2 ml of methanol are added. After 20 minutes of refluxing allowed to cool and diluted with abs. Methanol to 30 ml. The polymer product will then precipitated with ether. After standing at OOC for 2 hours, the precipitate is filtered off and washed. The product is dissolved in methanol with heating and with ether turned out as usual.

6. Iron incorporation in the polymer obtained according to Example 5: 0.42 g of product 5.11 are mixed with 1 ml of pyridine, dissolved in 40 ml of glacial acetic acid (p.a.) and with Gassed with nitrogen.

2 mM FeSO4 7 7H20 in a few ml of H20 are added to this solution of 12 minutes at 60-7O0C under nitrogen and stirring. After that 10 Stirred for minutes in the air and then concentrated to dryness.

The residue will. in least Dissolved H20 and adjusted to pH 7. After 2 hours, the precipitate is filtered off, the precipitate is washed and the filtrate is chromatographed on Sephadex (R) G 25.

Example 7 Reduction of the polymeric metal complexes: The ones to be reduced polymeric metal compound is dissolved in a few ml of 0.05 M phosphate buffer (pH 7.7) and gassed with nitrogen. Then sodium dithionite in 0.05 M phosphate buffer added (fv 50-fold excess).

With the exclusion of air, the solution is after about 5 minutes over a Column chromatographed with Sephadex G 25-fine (eluent: 0.05 M phosphate buffer pH 7.7).

Claims (3)

PATENT CLAIMS: 1. Synthetic polymeric soluble metal complex, characterized in that its central atom is a metal ion from group VIII, VIIb or Ib and that the polymer is covalently bonded to a tetradentate ligand and at least one other axial fifth ligand is bound to the central atom, wherein the polymer can be synthetic, semi-synthetic or natural. Process for the preparation of soluble polymeric metal complexes according to claim 1, characterized in that a low molecular weight, tetradentate Ligand or its metal complex via functional groups to soluble polymers, Copolymers or functionalized polymers of synthetic, semi-synthetic or of natural origin and bound at least one axial 5th ligand to the central atom is bound. 3. Use of a product according to claim 1 as an oxygen carrier.