RU2257377C2 - Organocobalt complexes with tridentate schiff's bases as initiators of emulsion polymerization and copolymerization of diene and vinyl monomers - Google Patents

Abstract

FIELD: organometallic polymerization catalysts.

SUBSTANCE: invention relates to alkylcobalt(III) complexes with tridentate Schiff's bases wherein alkyl ligand contains functional group, notably hydroxyl, carboxyl, or amino group, in accordance with general formula:

(I),

in which W represents two-moiety unsaturated hydrocarbon bridge group expressed by formula =C(H)=C(CH₃)- (propene-1,2-diyl) or o-C₆H₄ (o-phenylene); X is OH, NH₂ or COONa; Y monovalent anion: Cl^-, Br^-, NO₃ ^- or ClO₄ ^-; and Z polymethylene bridge group (CH₂)_n, wherein n=3-11 when X = OH or NH₂ and n=2-11 when X = COONa. The complex are used as initiators of emulsion polymerization and copolymerization of diene and vinyl monomers to produce reactive bifunctional oligomers and polymers with terminal functions, which oligomers and polymers are suitable for further conjugation with corresponding reagents.

EFFECT: extended choice of specific polymerization catalysts.

3 tbl, 30 ex

Description

The invention relates to the fields of chemistry of organometallic compounds and polymers, in particular to alkyl cobalt (III) complexes with Schiff tridentates, in which the alkyl ligand contains a functional, namely hydroxyl, carboxyl or amino group, and the use of these complexes as initiators of emulsion polymerization and copolymerization of diene and vinyl monomers to produce reactive bifunctional oligomers and polymers with such end groups.

The introduction of functional groups into the polymer can be used to immobilize biologically active compounds, for example, to obtain immunodiagnostics and vaccination of catalysts (Hartley F. Fixed metal complexes - a new generation of catalysts. M: Mir, 1989), as well as to modify the properties of the polymer itself. Bifunctional oligomers obtained in a similar manner can serve as starting materials (components) for the production of polycondensation (co) polymers.

Until now, when using the emulsion polymerization method for this purpose, appropriately functionalized peroxides and azo compounds have been used as initiators (Ivanchev S.S., Uspekhi Khimii, 1991, 60, 1368-1390). However, in this case, the process has to be carried out at elevated (> 60 ° С) temperatures and relatively high initiator concentrations. The latter leads to the fact that the number of functional groups on the surface of a polymer particle far exceeds the optimum. As a result, surface lyophilization occurs and, as a result, the stability of these particles in physiological solution decreases when such suspensions are used as carriers of bioligands. On the contrary, in the case of using the proposed initiators, it is possible to control the number of functional groups on the particle surface by varying the initiator concentration.

It is known to use alkyl cobalt (III) complexes with a Schiff tridentate base - alkyl {2 - [(2-aminoethyl) imino] -3-alkyl-pent-3-en-4-olate} - (1,2-ethanediamine) cobalt (III ) bromides (I, where XZ is a simple, i.e., functionally unsubstituted alkyl group C _n H _{2n + 1} , and Y = Br), as initiators of emulsion polymerization (RF patent No. 2070202, 1991). These compounds are highly effective emulsion polymerization initiators operating at room and even lower temperatures; however, they do not introduce functional groups into the polymer.

The objective of the invention was to obtain new high-performance low-temperature emulsion polymerization initiators containing a hydroxyl, carboxyl or amino group in the initiating radical, which are suitable for subsequent conjugation of the resulting polymers with the corresponding reagents.

This problem is solved by the new structure of complexes (functionally substituted alkyl) of cobalt with Schiff tridentate bases of the general formula I

where W is a bridged two-unit unsaturated hydrocarbon group, namely —C (H) = C (CH ₃ ) - (propen-1,2-diyl, A), or о-С ₆ H ₄ (o-phenylene, B), X = OH, NH ₂ or COONa, Z is a saturated hydrocarbon bridging group, namely the polymethylene ((CH ₂ ) _n ) group, and Y is a singly charged anion, namely, Cl ^- , Br ^- , I ^- , NO ₃ ^- or ClO ₄ ^- . Until now, alkyl cobalt complexes with Schiff tridentate bases containing functional groups in the alkyl ligand have not been known.

Comparative analysis with analogues allows us to conclude that compounds of a new structure are proposed. Thus, the claimed technical solution meets the criterion of "novelty."

The indicated complexes are (ω-hydroxy-n-alkyl) -, (ω-amino-n-alkyl) - and [ω - (sodium carboxylato) -n-alkyl] {2 - [(2-aminoethyl) imino] pent- 3-en-4-olyato} - and - (2- {1 - [(2-amino-ethyl) imino] ethyl} phenolato) (1,2-ethanediamine) cobalt (III) bromides *, chlorides, iodides, nitrates and perchlorates (symbolic formulas [X (CH ₂ ) _n Co (acacen) (en)] Y (IA) and [X (CH ₂ ) _n Co (7-Me-salen) (en)] Y (IB), respectively ) first obtained by the authors, as described below.

Complexes I with a bromide counterion (Y = Br) and X = OH, COONa, Br ** were synthesized using the template method, mainly by analogy with published methods for preparing the corresponding complexes with simple ones, i.e. functionally unsubstituted alkyl ligands of C _n H _{2n + 1} , namely, complexes of the series [RCo (acacen) (en)] Br (RF patent 2070202, 1991) and [RCo (7-Me-salen) (en)] Br (I. Ya. Levitin et al., Inorg. Synth. (S. Kirschner, ed.), Wiley, New York, 1985, v.23, pp. 163-171), under anaerobic conditions and with constant stirring. Complexes with other counterions (Y = Cl, I, NO ₃ , ClO ₄ ) were obtained starting from the corresponding bromides by ion exchange reactions in solutions, also by analogy with complexes with simple alkyl ligands (I. Ya. Levitin et al., Inorg. Chim. Acta, 1985, 100, 65-77). Complexes, if possible, protected from light during all operations and stored in the dark. Evaporation of solutions was carried out in vacuum at a bath temperature of not higher than 30 ° C.

The complexes were identified and characterized using elemental analysis (table 1 *), 1 H-NMR, IR and electron spectroscopy, as well as TLC and capillary electrophoresis. Their yields and chromatographic characteristics are shown in table 2.

* as well as (ω-bromo-n-alkyl) {2 - [(2-aminoethyl) imino] pent-3-en-4-olato} - and - (2- {1 - [(2-aminoethyl) imino ] ethyl} -phenolato) (1,2-ethanediamine) cobalt (III) bromides ([Br (CH ₂ ) _n Co (acacen) (en)] Br and [Br (CH ₂ ) _n Co (7-Me-salen ) (en)] Br), which are intermediate products in the synthesis of the corresponding ω-amino-substituted complexes

** see previous note

* the numbering of the complexes is also given there

Option (I): Preparation of 6-hydroxyhexyl {2 - [(2-aminoethyl) imino] pent-3-en-4-olate} (1,2-ethanediamine) cobalt (III) bromide ([HO (CH ₂ ) ₆ Co (asasep) (en)] Br, No. 4).

A solution of acetylacetone - 3.08 ml (30 mmol) and ethylenediamine - 2.01 ml (30 mmol) in methanol (110 ml) was kept until it turned yellow. Then CoCl ₂ · 6H ₂ O was added - 3.6 g (15 mmol). Upon cooling with water, sodium hydroxide was gradually sprinkled with the resulting brown solution — 3.7 g (80 mmol); the solution turned into a carrot-red suspension. After the sodium hydroxide was dissolved, the water bath was heated to 25 ° C. Then, a 2% solution of PdCl ₂ in a 1 M aqueous solution of KCl — 0.3 ml and 2.94 ml (22.5 mmol) of 6-bromohexanol was added. After this, the reaction flask was protected from light. Then, ^l / ₁₀ part of a solution of 0.8 g (20 mmol) of NaBH ₄ in a solution of 0.4 g (≈ 10 mmol) of NaOH in 5 ml of methanol was added. The remaining solution was added gradually over 5 hours. After this, stirring the reaction mixture under anaerobic conditions continued for another hour. Then it was cooled for several hours at 0 ° C. The precipitate formed was filtered off and washed on the filter with methanol until the washing liquid ceased to stain. The washing liquid was combined with the mother liquor. The resulting solution was concentrated in vacuo to 30 ml and allowed to crystallize at 0 ° C. The resulting dark red precipitate was separated by filtration and dried by suction on a filter. Then it was washed with CH ₂ Cl ₂ until the wash liquid ceased to turn green. The red product remaining on the filter was dried by suction on the filter and finally in vacuum over calcium chloride. The crude product was purified by recrystallization from methanol. The complex thus isolated is a red crystalline powder.

Similarly, other complexes of the series [HO (CH ₂ ) _n Co (acacen) (en)] Br (No. 1-3, 5, 6) were obtained. Yields from 80% (n = 3) to 55% (n = 11) - see table. 2.

Option (2): Preparation of 5-aminoamyl {2 - [(2-aminoethyl) imino] pent-3-en-4-olate} - (1,2-ethanediamine) cobalt (III) bromide ([HO (CH ₂ ) ₅ Co (acasen) (en)] Br, No. 13).

a - Synthesis of the corresponding ω-bromoalkyl-cobalt complex ([Br (CH ₂ ) ₅ Co (acacen) (en)] Br, No. 12). - The synthesis was carried out by analogy with synthesis 1, with the difference that instead of 6 as an alkylating agent β-bromohexanol used 1,5-dibromopentane (6.13 ml - 45 mmol). The resulting (intermediate) product is a red crystalline powder.

b - Amination of the resulting ω-bromoalkyl-cobalt complex .- [Br (CH ₂ ) ₅ Co (acacen) (en)] Br (0.5 g) was dissolved in concentrated aqueous ammonia (70 ml). The resulting solution was left to stand at room temperature; the course of the reaction, which ended after 3 hours, was monitored by TLC under the conditions indicated in the table. 2. After adding Na ₂ CO ₃ (0.5 g), the resulting solution was concentrated in vacuo, and then extracted with dichloromethane. The extract was dried over Na ₂ SO ₄ and concentrated in vacuo. The product was precipitated with ether, filtered and dried on a filter. Got a red crystalline powder.

Options (3.4): Preparation of 2- (sodium carboxylato) ethyl- and 5- (sodium carboxylato) amyl {2 - [(2-aminoethyl) imino] pent-3-en-4-olate} (1,2 -ethanediamine) -cobalt (III) bromides ([NaOCO (CH ₂ ) _n Co (acacen) (en)] Br, n = 2, 5; Nos. 15 and 16).

The syntheses were carried out by analogy with synthesis 1, with the difference that instead of 6-bromohexanol, methanol solutions of 3-bromopropionate and 6-bromocaproate sodium, respectively, were used as the alkylating agent. They were prepared by adding 3-bromopropionic and 6-bromocaproic acids (22.5 mmol — 3.44 and 4.39 g, respectively) to cooled and stirred solutions of Na ₂ CO ₃ until gas evolution ceased; excess reagent was removed by decantation. Products are red crystalline powders.

Option (5): Obtaining 11-hydroxyundecyl (2- {1 - [(2-aminoethyl) imino] ethyl} phenolato) (1,2-ethanediamine) cobalt (III) bromide ([HO (CH ₂ ) ₁₁ Co ( 7-Me-salen) (en)] Br, No. 19).

The synthesis was carried out by analogy with synthesis 1, with the difference that o-hydroxyacetophenone (3.61 ml - 30 mmol) and 11-bromundecanol (5.65 g - 22.5 mmol) were used as ketoenol and an alkylating agent instead of acetylacetone and 6-bromohexanol. The product is a red crystalline powder.

Option (6) Obtaining 11- (sodium carboxylato) undecyl (2- {1 - [(2-aminoethyl) imino] ethyl} phenolato) - (1,2-ethanediamine) cobalt (III) bromide ([HO (CH ₂ ) ₁₁ Co (7-Me-salen) (en)] Br. No. 22), -

The synthesis was carried out by analogy with synthesis 5, with the difference that instead of 11-bromundecanol, an methanol solution of sodium 11-bromundecanoate prepared by adding 11-bromundecanoic acid (5.97 g - 22.5 mmol) Na ₂ CO to the cooled and stirred solution was used ₃ until gas evolution ceases; excess reagent was removed by decantation. The product is a red crystalline powder.

Option (7): Preparation of 6-hydroxyhexyl {2 - [(2-aminoethyl) imino] pent-3-en-4-olate} (1,2-ethanediamine) cobalt (III) chloride ([HO (CH ₂ ) ₆ Co (acasen) (en)] Cl, No. 8).

A saturated aqueous solution of PbCl ₂ (0.35 g - 1.25 mmol) was added dropwise to an almost saturated solution of [HO (CH ₂ ) ₆ Co (acacen) (en)] Br (1.10 t - 2.5 mmol) in methanol. After separation of the precipitate formed (PbBr ₂ ) by decantation, a twofold volume of cold water was added to the resulting solution and it was evaporated in vacuo until crystallization began. Finally crystallized at 0 ° C. The precipitated product was separated by filtration, washed with a small amount of ice water and dried on the filter. Received a red crystalline powder, yield 82%.

Similarly, based on the corresponding complexes I, Y = Br, other complexes with the chloride counterion I, Y = Сl were obtained (No. 7, 17, 20).

Option (8): Preparation of 6-hydroxyhexyl {2 - [(2-aminoethyl) imino] pent-3-en-4-olate} (1,2-ethanediamine) cobalt (III) iodide ([HO (CH ₂ ) ₆ Co (asasen) (en)] I, No. 10).

An almost saturated solution of [HO (CH ₂ ) ₆ Co (acacen) (en)] Br (1 g) in methanol was added to a saturated aqueous solution (5 ml) of NaI. The precipitated product was separated by filtration, washed with a small amount of ice water and dried on the filter. Received dark red crystals, yield 85%.

Similarly, starting from the corresponding complexes I, Y = Br and, respectively, NaClO ₄ or NaNO ₃ (instead of NaI), complexes with perchlorate and nitrate counterions I, Y = ClO ₄ and NO ₃ (No. 9 and 11, 18, 21) were obtained .

Examples of the synthesis of polymers in the presence of complexes I are given below. The initiators are given under the numbers given in table. 1.

Example 1 (according to the invention)

In a stirred reactor, 100 wt. including styrene, purified by double recondensation under vacuum, with an aqueous phase comprising 4 wt. including sodium alkyl sulfonate (E-30) with a length of the alkyl substituent C ₁₅ , initiator No. 9, and 200 wt. including water. The process is carried out with stirring in a nitrogen atmosphere at a temperature of 40 ° C and a pH of 7, for 5 hours to a conversion of 97%. The polymer contains 0.01% by weight of OH ^- groups.

Examples 2-7.

Perform analogously to example 1, with a change in the type of monomers, initiators, emulsifiers, temperature, pH and concentration of the ingredients.

Example 8 (comparative)

In a stirred reactor, 100 wt. including styrene, purified by double recondensation under vacuum, with an aqueous phase comprising 4 wt. including sodium alkyl sulfonate (E-30) with a length of alkyl substituent C ₁₅ , the initiator, consisting of 0.11 wt. including complex with an octyl substituent and 200 wt. including water. The process is carried out with stirring in a nitrogen atmosphere at a temperature of 20 ° C and pH = 7 for 5.0 hours to a conversion of 94%. The polymer does not contain functional groups.

The formulation and results of the use of complexes I as initiators of emulsion polymerization are shown in table 3.

The presence in the polystyrene obtained by initiating polymerization by complexes I, X = OH or NH ₂ , Z = (CH ₂ ) ₅ and Y = Br of functional groups containing a mobile hydrogen atom was proved by luminescence analysis using fluorosceinisothiocyanate as a label .

To increase the content of functional groups in the polymer, a molecular weight regulator can be introduced into the reaction mixture. The pH of the emulsion system is maintained by known buffering systems.

Claims (1)

Organocobalt complexes with tridentate Schiff bases of the general formula I

where W is a bridged two-unit unsaturated hydrocarbon group, namely —C (H) = C (CH ₃ ) - (propene-1,2-diyl) or o-C ₆ H ₄ (o-phenylene); X (functional group) - OH, NH ₂ or COONa; Y is a singly charged anion, namely Cl ^- , Br ^- , I ^- , NO ₃ ^- or ClO ₄ ^- , Z is a saturated hydrocarbon bridged, namely polymethylene, (CH ₂ ) _n group, where the number of units is n = 3-11 if X = OH or NH ₂ , and n = 2-11 if X = COONa; as initiators of emulsion polymerization and copolymerization of vinyl and diene monomers.