Patent Application: US-48593505-A

Abstract:
compounds of formula are disclosed . the tetrapyrole ring in formula can be substituted with a metal cation ; r 1 , r 2 , r 3 and r 4 separately represent a hydrogen atom , a c1 - 4 alkyl or alkyloxy radical , or a phenyl radical optionally substituted by vinyl , hydroxy , nitro , amino , bromo , chloro , fluoro , iodo , benzyloxy , or hydroxymethyl radicals ; r 5 , r 6 , r 7 and r 8 separately represent a hydrogen atom or a c1 - 4 alkyl radical ; r a , r b and r c separately represent a hydrogen atom , a c1 - 4 alkyl or alkyloxy radical optionally substituted by a halogen , or a phenyl radical optionally substituted by vinyl , hydroxy , nitro , amino , bromo , chloro , fluoro , iodo , benzyloxy , or hydroxymethyl radicals , wherein at least one of r a , r b , and r c is a phenyl radical . compounds of formula bound to a silica , a sol - gel material or a mesoporous silica are useful for selective trapping of carbon monoxide .

Description:
according to a first specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which just one of the r a , r b or r c groups represents an unsubstituted phenyl radical or a phenyl radical substituted by one or more identical or different groups chosen , independently of one another , from vinyl , hydroxyl , nitro , cyano , carboxyl , amino , bromo , chloro , fluoro , iodo or benzyloxy radicals , linear or branched alkyl radicals comprising from 1 to 4 carbon atoms or linear or branched alkyloxy radicals comprising from 1 to 4 carbon atoms , said alkyl and alkyloxy radicals themselves being either unsubstituted or substituted by one or more bromo , chloro , fluoro or iodo groups . according to a second specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which just one of the r a , r b or r c groups represents a radical chosen from the 4 - bromophenyl , 4 - chlorophenyl , 4 - iodophenyl , 4 - nitrophenyl , 4 - cyanophenyl , 4 - carboxyphenyl , 4 - hydroxyphenyl , 4 - aminophenyl , 4 -( hydroxymethyl ) phenyl or 4 - vinylphenyl radicals and the other two groups from r a , r b or r c each represent a hydrogen atom . according to a third specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which r a and r b each represent a hydrogen atom . according to a fourth specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which either r a and r c or r b and r c each represent a hydrogen atom . according to a fifth specific aspect of the present invention , the three groups r a , r b and r c each represent a hydrogen atom . according to a sixth specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which r 1 , r 2 , r 3 and r 4 , which are identical or different , represent , independently of one another , an unsubstituted phenyl radical or a phenyl radical substituted by one or more identical or different groups chosen , independently of one another , from vinyl , hydroxyl , nitro , amino , cyano , carboxyl , bromo , chloro , fluoro , iodo or benzyloxy radicals , linear or branched alkyl radicals comprising from 1 to 4 carbon atoms or linear or branched alkyloxy radicals comprising from 1 to 4 carbon atoms , said alkyl and alkyloxy radicals themselves being either unsubstituted or substituted by one or more bromo , chloro , fluoro or iodo groups . according to a seventh specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which r 5 , r 6 , r 7 and r 8 , which are identical or different , represent , independently of one another , a linear or branched alkyl radical comprising from 1 to 4 carbon atoms and more particularly a methyl radical or an ethyl radical . according to an eighth specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which r 5 , r 6 , r 7 and r 8 are identical and each represent a methyl radical or an ethyl radical . according to a ninth specific aspect , a subject matter of the invention is a compound of formula ( i ) as defined above in which r 1 , r 2 , r 3 and r 4 are identical and each represent a phenyl radical . another subject matter of the invention is a compound of formula ( ii ): r 1 , r 2 , r 3 , r 4 , r 5 , r 6 , r 7 , r 8 , r a , r b and r c are as defined above and m represents a metal cation chosen from the cobalt ( co ), rhodium ( rh ), iridium ( ir ), manganese ( mn ), iron ( fe ), ruthenium ( ru ) and osmium ( os ) ions , y represents an organic or inorganic anion and α represents an integer or decimal number so that the compound of formula ( ii ) is electrically neutral . y is chosen from the anions conventionally used in the chemistry of organometallic complexes and more particularly from the chloride , bromide , iodide , acetate , trifluoroacetate , propionate , benzoate , trifluoromethylsulfonate , mesylate , benzenesulfonate , tosylate or tetrafluoroborate anions . according to a tenth specific aspect of the present invention , a subject matter of the latter is an organometallic complex , the cationic part of which is represented by the formula ( ii ′) as defined above in which m represents a metal cation chosen from fe ( iii ) and co ( iii ). another subject matter of the invention is a silica modified by a compound of formula ( i ) or of formula ( ii ) as defined above in which at least one of the r a , r b or r c groups represents an unsubstituted phenyl radical or a substituted phenyl radical , characterized in that the spacer arms which make possible the anchoring of the molecules of formulae ( i ) or of the cations of formulae ( ii ′) to silica gel are , on the one hand , bonded to said compounds via one of the 2 -, 3 - or 4 - positions of one or more of the phenyl radicals represented by at least one of the r a , r b or r c groups and , on the other hand , bonded to one or more of the free silanol functional groups of a silica gel via a covalent bond si — o . according to an eleventh specific aspect of the present invention , in the modified silica as defined above , the divalent radical connecting to the silicon atom participating in one or more covalent bonds si — o and the 2 -, 3 - or 4 - position of said phenyl radical is chosen from the following divalent radicals : — ch ═ ch —, — nh —( ch 2 ) n —, — o —( ch 2 ) m — or — nh ( c ═ o )— ch 2 — nh —( ch 2 ) p —, in which n , m and p , which are identical or different , represent , independently of one another , an integer greater than or equal to 0 and less than or equal to 4 . another subject matter of the invention is a sol - gel material derived from a compound of formula ( i ) or from a compound of formula ( ii ) as defined above in which the three r a , r b and r c groups represent an unsubstituted phenyl radical or a substituted phenyl radical , characterized in that the 2 -, 3 - or 4 - position of said phenyl radicals is substituted by a monovalent radical having an end group : in which r 14 represents a methyl radical , an ethyl radical or an isopropyl radical . according to a twelfth specific aspect of the present invention , a subject matter of the latter is a sol - gel material as defined above in which the monovalent radical having an end group — si ( or 14 ) 3 is chosen from the following radicals : — ch ═ ch — si ( or 14 ) 3 , — nh —( ch 2 ) n — si ( or 14 ) 3 , — o —( ch 2 ) m — si ( or 14 ) 3 in which n , m and p , which are identical or different , represent , independently of one another , an integer greater than or equal to 0 and less than or equal to 4 and r 14 represents a methyl radical , an ethyl radical or an isopropyl radical . another subject matter of the invention is a mesoporous silica modified by a compound of formula ( i ) or of formula ( ii ) as defined above in which at least one of the r a , r b or r c groups represents an unsubstituted phenyl radical or a substituted phenyl radical , characterized in that the spacer arms which make possible the anchoring of the molecules of formulae ( i ) or of the cations of formulae ( ii ′) to silica gel are , on the one hand , bonded to said compounds via one of the 2 -, 3 - or 4 - positions of just one or several of the phenyl radicals represented by at least one of the r a , r b or r c groups and , on the other hand , bonded to one or more of the free silanol functional groups of the mesoporous silica via a covalent bond si — o . according to a thirteenth specific aspect of the present invention , in the modified mesoporous silica as defined above , the divalent radical connecting the silicon atom participating in one or more covalent bonds si — o and the 2 -, 3 - or 4 - position of said phenyl radical is chosen from the following divalent radicals : — ch ═ ch —, — nh —( ch 2 ) n —, — o —( ch 2 ) m — or — nh ( c ═ o )— ch 2 — nh —( ch 2 ) p —, in which n , m and p , which are identical or different , represent , independently of one another , an integer greater than or equal to 0 and less than or equal to 4 . another subject matter of the invention is a process for the separation of carbon monoxide from a gas mixture comprising it , characterized in that said mixture is brought into contact with either a compound of formula ( ii ), or with a silica modified by a compound of formula ( ii ), or with a sol - gel material of compound of formula ( ii ), or with a mesoporous silica modified by a compound of formula ( ii ), as defined above , so as to bring about the adsorption of the carbon monoxide on said compounds . such a process can be employed to detect the presence of carbon monoxide in a given atmosphere and more particularly in humid air . it can also be employed to separate carbon monoxide from hydrogen in the processes in industrial chemistry which result in this mixture . the following experimental part illustrates the invention without , however , limiting it . the synthesis represented in fig3 is carried out by condensation of two equivalents of carboxy - pyrrole with an appropriate dipyrromethane with acid catalysis . an intermediate of biladiene “ a - c ” type is easily obtained , which intermediate is cyclized under the action of a base before being subjected to an oxidation reaction in order to form the corrole . 3 , 4 under some conditions , it is possible to directly synthesize the corrole macrocycle in a single stage . this reaction 5 , represented in fig4 , is carried out without solvent and can be carried out in the presence of a solid support of alumina type . this method , represented in fig5 , consists in bringing together a dipyrromethane and a dipyrryl sulfide in methanol in an acidic medium 6 . the intermediate compound is a “ meso ” thiamacrocycle , the structure of which depends on the nature of the substituents in the β - pyrrole position . the extrusion of the sulfur can be obtained by thermolysis in dichlorobenzene and in the presence of triphenylphosphine . however , this synthetic route does not at present allow high yields of corrole to be obtained . the metallation of the corrole , represented in fig6 , is easily carried out by cobalt diacetate in a chcl 3 / ch 3 oh mixture at reflux . another access route , represented in fig7 , uses the template effect of the cobalt ion 7 - 9 to directly obtain the cobalt complex . however , this methodology presupposes access to a complex , the central element of which carries an axial phosphine ligand which may partially inhibit the subsequent coordination of the carbon monoxide . the three cobalt complexes chosen as examples for studying the properties of carbon monoxide and oxygen are represented in fig8 . the affinity of co ( iii ) for carbon monoxide will depend on the electron density present on the lewis acid metal . the more depleted the metal ion in electrons ( by the presence of electron - withdrawing substituents on the corrole ), the greater should be its affinity with regard to carbon monoxide . consequently , corrole iii should therefore be expected to have a greater affinity for co in comparison with corroles i and ii ( fig9 ). this scale of reactivity for corroles i , ii and iii will be confirmed , first , by the measurement of the half - saturation pressure p 1 / 2 ( co ) and , secondly , by that of the frequency of infrared vibration of the co bond . adsorption of co by the various complexes was measured at 21 ° c . on an asap 2010 micromeritics ™ device . the experimental data obtained were processed by a nonlinear adjustment according to a law of langmuir type : in which formula v m is the maximum volume of gas coordinated to the co ( iii ), k is the stability constant corresponding to the equilibrium : in all cases , two langmuir isotherms are necessary to account for the adsorption phenomenon which has to be caused by the cobalt sites having different accessibility in the solid state , as is represented in fig1 . in this figure , it is noticed that , even if the cobalt sites are identical from a chemical viewpoint , they are not identical from a “ geographical ” viewpoint , that is to say that the active sites do not all have the same accessibility for carbon monoxide . this is because , by route 2 , carbon monoxide has first to diffuse into the solid before being able to be chemisorbed . in order to account for this phenomenon , it has therefore been necessary to make use of two p 1 / 2 ( co ) values , i . e . two langmuir isotherms . the complex i does not fix carbon monoxide in the solid state . this result is particularly important since it demonstrates that the adsorption of carbon monoxide cannot be attributed solely to a co ( iii ) entity . this observation is in agreement with the literature results , for which no coordination of carbon monoxide had been demonstrated with a co ( iii ) complex . in the present case , the complex i does not possess a sufficient lewis acidity to make possible the creation of a co ( iii )- co bond . the isotherm for adsorption of carbon monoxide by the complex ii is represented in fig1 . the total volume of carbon monoxide at one atmosphere is 4 . 11 cm 3 . g − 1 , i . e . a yield of 10 % with respect to the number of potential sites of the molecule . this result is in agreement with poor accessibility of the co ( iii ) sites within the solid compound . a dispersion of corrole in a film of langmuir - blodgett type or the immobilization of the complex on a solid support of silica or organic polymer type , for example , should render the sites more accessible . however , for an application of sensor type , whatever the volume of co adsorbed , the detection limits of the sensor will be determined by the co partial pressure from which the chemosorption of the gas on the corrole occurs . corrole ii fixes co from low gas pressures . the thermodynamic constants were determined by the nonlinear least squares adjustment method with two langmuir isotherms ( fig1 ). a very good match between the experimental values and the calculated isotherm is obtained from two langmuir isotherms . this results in a p 1 / 2 ( co ) of 20 . 6 torr for the first langmuir isotherm , indicating good affinity of the complex ii for co . this isotherm reflects the chemosorption of co on readily accessible co ( iii ) sites , whereas the second langmuir isotherm accounts both for the diffusion and for the adsorption of the gas on the sites accessible with difficulty . this is why the p 1 / 2 ( co ) for the second isotherm is very high in this case : 1 303 torr . subsequently , only the p 1 / 2 ( co ) relating to the first langmuir isotherm will be taken into account . it is important to note that the adsorption of co indeed corresponds to a phenomenon of chemosorption at the cobalt atom . for this , the properties of adsorption of co on corrole iv , represented in fig1 , the potential sites of which for fixing the gas are blocked by two imidazole molecules , were studied . corrole iv does not fix carbon monoxide , even at co pressures of 850 torr . the infrared spectrum of this compound does not exhibit vibration bands characteristic of co fixed to a metal . these two results confirm that co is indeed bonded to the co ( iii ) in corrole ii . for the purpose of an application as carbon monoxide sensor , it is necessary for the process of fixing the gas to be reversible . after degassing the compound ii / co under 10 − 3 torr for 12 h , a second isotherm was recorded . this isotherm and that corresponding to the first adsorption are represented in fig1 . this figure demonstrates the complete reversibility of the system with regard to co , since the volume of co adsorbed after the second cycle is identical to that measured after the first cycle . this complete reversibility is confirmed by the infrared analysis in diffuse reflection mode of the compound ii / co ( fig1 ). the infrared analysis confirms the good reversibility of the system . this is because , in fig1 , a gradual desorption of the co is indeed observed when the complex is re - exposed to the air ( spectra 1 to 5 ). this desorption results from the decrease in the co partial pressure in the system . it subsequently becomes complete when the corrole ii is degassed under 3 torr over 5 min , since no band is present at 2 045 cm − 1 in the infrared ( spectrum 6 ). fig1 represents the isotherm for adsorption of carbon monoxide for corrole iii , and the adjustment obtained with two langmuir isotherms . as for the preceding compounds , a very good match is observed between the experimental values and the adjustment obtained from two langmuir isotherms . the first value of p 1 / 2 ( co ) is 2 . 85 torr , which indicates an excellent affinity of the complex iii for co . if this result is compared with that obtained for corrole ii ( p 1 / 2 ( co )= 20 . 6 torr ), an increased affinity of corrole iii for co is observed in comparison with corrole ii . this confirms the hypothesis of a greater affinity with regard to co for the complexes in which the co ( iii ) atom is depleted in electrons ( see fig9 ). the affinity for carbon monoxide can therefore be adjusted as desired by addition of more electron - withdrawing or less electron - withdrawing substituents at the periphery of the corrole macrocycle . the reversibility of the co adsorption was also tested over four adsorption - desorption cycles for corrole iii . the corresponding isotherms are presented in fig1 . a partial reversibility is observed during the adsorption - desorption cycles . the total volume of co adsorbed at 850 torr is 5 . 22 - 5 . 34 cm 3 . g − 1 for the first two cycles and falls to 3 . 80 - 3 . 98 cm 3 . g − 1 for the third and fourth cycles . this result can be explained in that perhaps not all the sites were freed between the second and third cycles , given the high affinity of corrole iii for carbon monoxide . however , it should be pointed out that the value of p 1 / 2 ( co ) does not vary much according to the cycles . this partial reversibility is confirmed by the infrared analysis in diffuse reflection mode of the compound iii / co . even after degassing under 3 torr for 5 min , the band at 2 078 . 8 cm − 1 ( relating to the co vibration ) has not completely disappeared . this clearly demonstrates the strength of the co ( iii )- co bond in the case of corrole iii / co . many molecules are known for their properties of fixing carbon monoxide but , in all cases , they also fix oxygen . this absence of selectivity ( necessary for their use as sensor ) makes it impossible to use them for a process for detecting co in an ambient atmosphere . furthermore , cobalt or iron complexes , known for their ability to coordinate o 2 or co , prove to be unstable in air over time because of the presence of oxygen and of moisture . their application as sensor is therefore impossible . the co , o 2 and n 2 adsorption isotherms for corrole ii are presented in fig1 . they reveal the following points : 1 — the amount of n 2 or o 2 fixed is very low with respect to the volume of co adsorbed , in particular at low pressures . 2 — the nitrogen and oxygen adsorption isotherms are identical ; this indicates that the phenomenon involved corresponds to physisorption . from a chemical viewpoint , the co / o 2 or co / n 2 selectivity of the complex is therefore infinite . however , if this selectivity is regarded as being the ratio between the volumes of the various gases adsorbed at a given pressure , it is of the order of 50 for pressures below 5 torr ( insert in fig1 ). this co / o 2 or co / n 2 selectivity is markedly greater in the case of corrole iii , since the amount of co adsorbed is greater from low pressures . fig1 represents the co , o 2 and n 2 adsorption isotherms for corrole iii , and the two selectivity curves . the selectivity of the compound is noteworthy at low pressures , since it is of the order of 300 for pressures below 5 torr , i . e . six times that of corrole ii . this results simply from the greater affinity of corrole iii for co . the ratio of the p 1 / 2 ( co ) values for the two complexes reveals a factor of 7 in favor of corrole iii . such a co / o 2 selectivity in the solid state is without precedent in the literature and brings to prominence the advantage of such molecules in the field of sensors . these results are compared with those obtained for an iron ( ii ) porphyrin of picket fence type known for more than 20 years for coordinating , in organic solution , o 2 and co with a very high selectivity with regard to co . 1 , 10 we presented , in fig1 , the structure of the picket - fence iron ( ii ) porphyrin (( to - pivpp ) fe ( 1 , 2 - me 2 im )) with a base of imidazole type coordinated to the iron atom . co or o 2 coordinates to the vacant site of the iron ( ii ) in the porphyrin cavity 11 . this porphyrin complex is in fact currently one of the best synthetic models for myoglobin and hemoglobin since it reversibly coordinates oxygen 1 , 10 , 12 , 13 . this coordination involves an electron transfer from the metal to the oxygen , thereby generating a superoxide anion and bringing about the formal oxidation of iron ( ii ) to iron ( iii ). thus , the metal centers capable of fixing an oxygen molecule have to have a vacant coordination site and a low degree of oxidation . the formation of the oxygenated entity is stabilized , on the one hand , by the presence of a distal cavity ( coordination site opposite to the base ) and , on the other hand , by the existence of hydrogen bonds within the cavity between the amide groups of the pivaloyl pickets and the superoxide anion . by modifying these two parameters , it is possible to greatly vary the selectivity of these complexes with regard to oxygen and carbon monoxide . as has been indicated , this molecule is one of the compounds having the greatest affinity in solution for co . it also fixes oxygen in solution but less strongly . the values of the thermodynamic constants relating to the fixing of co and o 2 by this complex are listed in table 1 below . the ratio m , representative of the co / o 2 selectivity , is one of the highest to date . however , these values were obtained in solution and have never been recorded in the solid state for carbon monoxide , and just one publication describes the coordination of oxygen 14 to picket - fence iron ( ii ) in a solid state . it was therefore important to carry out a full study in the solid state by making series of measurements analogous to those carried out on the corroles . fig2 represents the isotherm for adsorption of carbon monoxide in the solid state for ( to - pivpp ) fe ( 1 , 2 - me 2 im ), and the adjustment obtained with two langmuir isotherms . a p 1 / 2 ( co ) value of 0 . 63 torr was calculated for the first langmuir isotherm , indicating an excellent affinity of ( to - pivpp ) fe ( 1 , 2 - me 2 im ) for co . as in the case of the corrole complexes , the second langmuir isotherm accounts both for the diffusion and for the adsorption of the gas on less accessible sites . however , the p 1 / 2 ( co ) is relatively low : 23 torr . this reflects a good affinity of these “ less accessible ” sites for co . the total volume adsorbed at p = 850 torr is 9 . 29 cm 3 . g − 1 , which represents 50 % of the active sites . the reversibility of ( to - pivpp ) fe ( 1 , 2 - me 2 im ) with regard to co was also studied ( see fig2 ). under relatively mild degassing conditions ( 50 ° c . ), the fixing of co to ( to - pivpp ) fe ( 1 , 2 - me 2 im ) is not completely reversible ( cycles 1 - 3 , fig2 ). this is explained by a very strong bond existing between the iron and the co . on the other hand , after degassing at 120 ° c . for 12 h , the total volume adsorbed is slightly greater than that obtained during the first cycle ( isotherms 1 and 4 ). it should also be noted that , for the four cycles , the value of p 1 / 2 ( co ) is between 0 . 3 and 0 . 6 torr . the great stability of the fe — co bond is confirmed by the infrared analysis in diffuse reflection mode of ( to - pivpp ) fe ( 1 , 2 - me 2 im )/ co ( fig2 ). for compounds possessing an fe — co bond , the band corresponding to the vibration of the co bond appears at a low frequency , which indicates that the fe — co bond is strong , because of a very marked π retrodonation from the metal to the ligand . fig2 represents the isotherm for adsorption of oxygen in the solid state for ( to - pivpp ) fe ( 1 , 2 - me 2 im ), and the adjustment obtained with two langmuir isotherms . a p 1 / 2 ( o 2 ) value of 34 . 2 torr was calculated for the first langmuir isotherm , indicating a good affinity of the compound for o 2 . this affinity is markedly lower than for co ( p 1 / 2 ( co )= 0 . 63 torr ; fig2 ). a behavior in agreement with that obtained in solution is clearly re - encountered here . the total volume adsorbed at p = 850 torr is 9 . 29 cm 3 . g − 1 ( result identical to that obtained for co ), which represents 50 % of the active sites . likewise , the reversibility of ( to - pivpp ) fe ( 1 , 2 - me 2 im ) with regard to o 2 was studied ( see fig2 ). in contrast to what was observed for carbon monoxide , the reversibility appears to be better for oxygen , since the total volume adsorbed does not decrease very much between each cycle . this is explained by a weaker bond between o 2 and the iron ; mild degassing conditions are then sufficient to desorb o 2 . complete reversibility should be obtained by heating under vacuum . the values obtained for the cobalt ( iii ) corroles and for ( to - pivpp ) fe ( 1 , 2 - me 2 im ) are presented in table 2 . it is important to remember that the oxygen adsorbed by the corroles corresponds to a physisorption phenomenon . conversely , for ( to - pivpp ) fe ( 1 , 2 - me 2 im ), a chemical bond between the iron and o 2 is involved . the “ chemical ” selectivity is therefore infinite for corroles ii and iii . however , even taking into account physisorbed o 2 , corrole iii exhibits a markedly greater selectivity than that obtained for the porphyrin . furthermore , it can be handled in the air and does not decompose in the presence of moisture . these results , which are without precedent , demonstrate the potentialities of such a molecule in various fields of application and in particular in that of carbon monoxide sensors . 15 ml of 33 % hydrobromic acid in acetic acid are added to a suspension of 2 . 38 g ( 7 . 5 mmol ) of 5 , 5 ′- dicarboxy - 3 , 3 ′- diethyl - 4 , 4 ′- dimethyldipyrrylmethane and of 2 . 26 g ( 15 mmol ) of 3 , 4 - diethyl - 2 - formylpyrrole [ or 2 . 15 g ( 7 . 5 mmol ) of 3 , 3 ′- diethyl - 5 , 5 ′- diformyl - 4 , 4 ′- dimethyldipyrrylmethane and 2 . 51 g ( 15 mmol ) of 2 - carboxy - 3 , 4 - diethylpyrrole ] in 120 ml of ethanol at reflux . the reaction mixture is then brought to reflux for 10 minutes . after cooling the solution , the biladiene - a , c ( reaction intermediate ) precipitates during the addition of 150 ml of diethyl ether . the biladiene - a , c is filtered off , rinsed with ether and dried . a purple powder is obtained with a yield of 70 %. the biladiene - a , c is subsequently dissolved in 500 ml of methanol saturated with nahco 3 and the solution is stirred for 10 minutes . 730 mg of p - chloranil are subsequently added and , after stirring for an additional 10 minutes , 7 ml of 50 % hydrazine hydrate in water are added . after stirring for 10 minutes , the corrole precipitates in the form of a purple - pink powder . the corrole is then filtered off and washed copiously with water . the corrole is subsequently recrystallized from a ch 2 cl 2 / ch 3 oh mixture , filtered off and dried . proton nmr ( cdcl 3 ) ( δ in ppm ): − 2 . 93 ( s , 3h , nh ); 1 . 84 ( t , 6h , ch 3 ); 1 . 87 ( t , 6h , ch 3 ); 1 . 89 ( t , 6h , ch 3 ); 3 . 38 ( s , 6h , ch 3 ); 3 . 90 ( q , 4h , ch 2 ); 3 . 95 ( q , 4h , ch 2 ); 4 . 06 ( q , 4h , ch 2 ); 9 . 51 ( s , 1h , h - 10 ); 9 . 53 ( s , 2h , h - 5 , 15 ). infrared spectrometry ( kbr ; v in cm − 1 ): 3350 ( nh ); 2961 ( ch ); 2928 ( ch ); 2867 ( ch ). uv - visible spectrophotometry ( ch 2 cl 2 ): λ max , nm ( ε × 10 − 3 m − 1 . cm − 1 ): 395 ( 126 . 5 ); 407 ( 101 . 2 ); 549 ( 18 . 9 ); 593 ( 23 . 6 ). after dissolution of 4 . 72 g ( 12 . 8 mmol ) of 5 , 5 ′- dicarboxy - 3 , 3 ′, 4 , 4 ′- tetramethyldipyrryltoluene in 200 ml of trifluoroacetic acid , the red solution is stirred at ambient temperature for 5 minutes . a solution of 7 g ( 25 . 6 mmol ) of 3 , 4 - diphenyl - 2 - formyl - pyrrole in 200 ml of methanol is then added dropwise . stirring is maintained for 15 minutes and 70 ml of 33 % hydrobromic acid in acetic acid are added . the reaction mixture is stirred for 15 minutes and then the solvents are evaporated . a solid is obtained which has green highlights ( biladiene - a , c ). the biladiene - a , c is then dissolved in 1 l of methanol saturated with nahco 3 and is stirred for 15 minutes . 4 . 3 g of p - chloranil are then added and the reaction medium is again stirred for 15 minutes . finally , 43 ml of 50 % hydrazine hydrate in water are added and , after stirring for an additional 15 minutes , the solvents are evaporated . the solid obtained is taken up in dichloromethane and washed with water to neutral ph . the organic phase is subsequently dried over mgso 4 , filtered and evaporated . the solid obtained is passed through an alumina chromatographic column ( eluent : 100 % ch 2 cl 2 ). the purple fraction which elutes in the solvent front is collected and evaporated . the corrole is subsequently recrystallized from a ch 2 cl 2 / ch 3 oh mixture , filtered off and dried . proton nmr ( cdcl 3 ) ( δ in ppm ): 2 . 22 ( s , 6h , ch 3 ); 3 . 17 ( s , 6h , ch 3 ); 6 . 57 - 7 . 95 ( m , 25h , ar — h ); 9 . 40 ( s , 2h , h - 5 , 15 ). uv - visible spectrophotometry ( ch 2 cl 2 ): 4 max , nm ( ε × 10 − 3 m − 1 . cm − 1 ): 418 ( 85 . 3 ); 566 ( 14 . 3 ); 604 ( 12 . 1 ). the synthesis described here was developed by the team of professor gross in 1999 5 . this synthesis makes it possible to obtain , in a single stage , a corrole from two commercial products at a lower cost . the synthesis is performed in the presence of a solid support of alumina type and is carried out without solvent . 2 . 94 g ( 15 mmol ) of pentafluorobenzaldehyde and 0 . 967 ml ( 15 mmol ) of pyrrole are added to 200 mg of alumina which is dehydrated and milled beforehand . the reaction mixture is stirred at 60 ° c . for 4 hours . the solid obtained is then dissolved in dichloromethane and 200 mg of ddq are added . the purple solution is evaporated and the solid obtained is passed through an alumina chromatographic column ( eluent : 100 % ch 2 cl 2 ). the purple fraction which migrates in the solvent front is collected and then evaporated . the corrole is subsequently recrystallized from a ch 2 cl 2 / ch 3 oh mixture , filtered off and dried . proton nmr ( cdcl 3 ) ( δ in ppm ): 7 - 9 ( 4 dd , 8h , hpyr .). the corrole is dissolved in chloroform and is brought to reflux . 1 . 2 equivalents of co ( o 2 cch 3 ) 2 , dissolved in the minimum amount of methanol , are added to this solution . the reaction medium is stirred at reflux for 10 minutes and then the solvents are evaporated . the solid is subsequently taken up in dichloromethane and washed with water . the organic phase is subsequently dried over mgso 4 , filtered and then evaporated . the cobalt corrole obtained is recrystallized from a ch 2 cl 2 / ch 3 oh mixture , filtered off and dried . the cobalt corroles are obtained with yields of greater than 90 %. the main analytical characteristics of the complexes obtained are summarized in the following table : the grafting to silica is carried out by anchoring the corrole macrocycle , which may or may not be metallated , via a functionalized arm to the free silanol functional groups of silica gel according to the following reaction process : the first stage consists of the addition of the functionalized arm to just one of the aryl groups r a , r b or r c of the corrole ( scheme 1 ). this arm can be functionalized by vinyl or amino groups or by a halogen atom . the length of this arm can vary from zero carbon atoms ( the functional group is then directly attached to the trialkoxysilane unit ) to a maximum of four atoms . the aryl residue to which the spacer arm will be attached is functionalized in the r 9 , r 10 , r 12 or r 13 position by the appropriate group according to scheme 1 . the second stage corresponds to the grafting of the functionalized macrocycle to the silica gel by reaction of the trialkoxysilyl unit with one , two or three accessible silanol functional groups of the silica ( scheme 2 ). the sol - gel materials are synthesized by proceeding in the following way : route 1 : polycondensation of corroles or metallocorroles mono -, di - and trisubstituted in the meso position ( r a , r b and r c ) by spacers possessing trialkoxysilyl endings ( scheme 3 ). the preliminary functionalization of the aryl groups r a , r b and r c will be carried out according to the same protocol as that described above for the grafting to the silica gel ( scheme 1 ). the polycondensation will be carried out by reaction of the trisubstituted corrole or metallocorrole mentioned beforehand with the stoichiometric amount of water in the presence of a catalyst ( fluoride , acid or base ) in any organic solvent which makes it possible to dissolve the reaction medium . route 2 : copolymerization of corroles or metallocorroles mono -, di - and trisubstituted in the meso position ( r a , r b and r c ) by arms possessing trialkoxysilyl endings with a tetraalkoxysilane ( formation of a cogel ) ( scheme 3 ). the functionalization of the corrole or metallocorrole is entirely identical to that described above . the copolycondensation will be carried out by reaction of the trisubstituted corrole or metallocorrole mentioned beforehand with the tetraalkoxysilane and the stoichiometric amount of water in the presence of a catalyst ( fluoride , acid or base ) in any organic solvent which makes it possible to dissolve the reaction medium . this family of materials , discovered by beck in 1992 , is known as mts ( mesoporous templated silica ) and two representatives of this family , known as hms ( hexagonal mesoporous silica ) or msu , correspond to our requirements . the arrangement of the hms or msu material is brought about by polycondensation of a hydrolyzable precursor in the presence of a neutral surface - active agent , such as a c 8 to c 18 primary amine ( hms ) or a polyethylene oxide ( msu ). the structuring agent is easily removed by extraction with ethanol . the removal of the surfactant thus releases hexagonal channels having a uniform mean diameter and exhibiting a noteworthy accessibility to various molecules . the anchoring of the corrole unit within the pores of the material can be carried out by reaction of the macrocycle , mono - or difunctionalized by a sequence comprising an end trialkoxysilane group , with the free silanol groups of the material ( scheme 4 ). the preliminary functionalization of the aryl groups r a and / or r b and / or r c is carried out according to the same protocol as that mentioned above ( scheme 1 ). the grafting to silica is carried out by anchoring the corrole macrocycle , which mayor may not be metallated , via a functionalized arm to the free silanol functional groups of silica gel according to the following reaction process : the first stage consists of the addition of the functionalized arm to just one of the aryl groups ra , r b or r c of the corrole ( fig2 ). this arm can be functionalized by vinyl or amino groups or by a halogen atom . the length of this arm can vary from zero carbon atoms ( the functional group is then directly attached to the trialkoxysilane unit ) to a maximum of four atoms . the aryl residue to which the spacer arm will be attached is functionalized in the r 9 , r 10 , r 12 or r 13 position by the appropriate group according to fig2 . the second stage corresponds to the grafting of the functionalized macrocycle to the silica gel by reaction of the trialkoxysilyl unit with one , two or three accessible silanol functional groups of the silica ( fig2 ). the sol - gel materials are synthesized by proceeding in the following way : route 1 : polycondensation of corroles or metallocorroles , mono -, di - and trisubstituted in the meso position ( r a , r b and r c ) by spacers possessing trialkoxysilyl endings ( fig2 ). the preliminary functionalization of the aryl groups r a , r b and r c , will be carried out according to the same protocol as that described above for the grafting to the silica gel ( fig2 ). the poly - condensation will be carried out by reaction of the trisubstituted corrole or metallocorrole mentioned beforehand with the stoichiometric amount of water in the presence of a catalyst ( fluoride , acid or base ) in any organic solvent which makes it possible to dissolve the reaction medium . route 2 : copolymerization of corroles or metallocorroles mono -, di - and trisubstituted in the meso position ( r a , r b and r c ,) by arms possessing trialkoxysilyl endings with a tetraalkoxysilane ( formation of a cogel ) ( fig2 ). the functionalization of the corrole or metallocorrole is entirely identical to that described above . the copolycondensation will be carried out by reaction of the trisubstituted corrole or metallocorrole mentioned beforehand with the tetraalkoxysilane and the stoichiometric amount of water in the presence of a catalyst ( fluoride , acid or base ) in any organic solvent which makes it possible to dissolve the reaction medium . this family of materials , discovered by beck in 1992 , is known as mts ( mesoporous templated silica ) and two representatives of this family , known as hms ( hexagonal mesoporous silica ) or msu , correspond to our requirements . the arrangement of the hms or msu material is brought about by polycondensation of a hydrolyzable precursor in the presence of a neutral surface - active agent , such as a c 8 to c 18 primary amine ( hms ) or a polyethylene oxide ( msu ). the structuring agent is easily removed by extraction with ethanol . the removal of the surfactant thus releases hexagonal channels having a uniform mean diameter and exhibiting a noteworthy accessibility to various molecules . the anchoring of the corrole unit within the pores of the material can be carried out by reaction of the macrocycle , mono - or difunctionalized by a sequence comprising an end trialkoxysilane group , with the free silanol groups of the material ( fig2 ). the preliminary functionalization of the aryl groups r a and / or r b and / or r c is carried out according to the same protocol as that mentioned above ( fig2 ). 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