IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Synthesis and Characterization of New Symmetrical Pyromellitdiimide Derivatives and Their Amic Acids E. T. Ali , K. M. Lazim AL-Aliawy and J. H. Tomma Department of Chemistry, College of Education , Ibn Al-Haitham University of Baghdad Received in : 29 March 2011 Accepted in : 30 May 2011 Abstract The new symmetry pyromellitdiimide [VII]a-c,n were synthesized by two-step reactions from the corresponding pyromellitic dianhydride . A new symmetrical amic acid [VI]a-c,n was synthesized by the reaction of pyromellitic dianhydride with different heterocyclic amines in dry acetone . The second reaction step includes intramolecular cyclization of amic acid in the presence of sodium acetate -acetic anhydride system at 85 0 C. Structures of the synthesized compounds have been ascertained by their melting points , C.H.N analysis , UV-Vis, FTIR and 1HNMR spectroscopy. Key words :Pyromellitdiimide , Pyromellitic dianhydride , Pyromellitamic diacid Introduction Pyromellitdiimides are best known as segments of highly insulating polyimides dielectrics, it is though nevertheless quit surprising that two attempt has been made to fabricate transistor from pyromellitdiimide derivatives . Pyromellitdiimides derivatives can be easily prepared by one –step reaction between pyromellitic dianhydride and various amines . The facile synthesis of pyromellitdiimide derivatives offers an advantage in larges scale synthesis due to its high conversion yield and ease of purification . Many workers synthesized new pyromellitimide derivatives by using this method in different conditions[1- 7]. Another method to synthesis pyromellitdiimide derivatives includes two step, firstly synthesis of amic acid by nucleophilic addition of amine to acid anhydride, secondly condensation amic acid by heating to yield pyromellitdiimide by ring closure [8-11]. The pyromellitimides containing heterocyclic units very rare [10,12] , therefore we decided to synthesis and characterized the new amic acid containing thiazole, benzothiazole or oxadiazole unit and their pyromellitdiimide derivatives. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Experimental Materials: All the chemicals were supplied from Merck , Fluka ,GCC and Aldrich chemicals Co. and used as received. Techniques : FTIR spectra were recorded using potassium bromide discs on a shimadzu (8400S) and shimadzu (IR Prestige-21).1HNMR spectra were carried out by company : Bruker , model: ultra shield 300 MHz , origin : Switzerland and are reported in ppm(S), DMSO was used as solvent with TMS as an internal standard. Measurements were made at chemistry department, AL-Albyat university, Elemental microanalysis (C.H.N) were carried out by a (C.H.N) company : Euro vector , model EA3000A origin : Italy . AL-Albayt University , Jordan . Uncorrected melting points were determined by using Hot-Stage, Gallen Kamp melting point apparatus .UV-Vis spectra of solution were performed on CECL 7200 England Spectrophotometer using CHCl3 as a solvent. Synthesis methods Ethyl-4-Amino benzoate [I]: was prepared following the procedure by Vogel [13] , yield 99%, m.p.910C, lit 910C . COH2N O C2H5 [I] 4-amino phenyl hydrazide[II]: This compound was prepared according to the let.[14] , yield 99.5%, m.p. 2230C, lit 2230C. H2N C NH O NH2 [II] 5-(4-amino phenyl)-1,3,4-Oxadiazole-2-thiol [III]: This compound was prepared according to the let. [15], y ield 79%, m.p. 239 0 C. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 H2N NN O SH [III] n-alkyl bromide[IV]n: was prepared following the procedure by Vogel [13]. n=2,4,7 CnH2n+1Br [IV]n 2-alkyl-thio-5-[4-amino phenyl ]-1,3,4-oxadiazole[V]: H2N NN O SCnH2n+1 n =2,4,7[V] Potassium hydroxide (0.68g, 0.12mole) dissolved in minimum volume of water, was added drop wise to a stirred solution of oxadiazole (1.93 g , 0.01 mole) in (10mL) of dioxane at 25 0C. After heating the mixture for (15min.) and cooling , n-alkyl bromide (0.01mole) was added drop wise . The solution was refluxed for (2 hours) ; afterwards the solvent was evaporated on a rotator evaporator. Ice-water (100 mL) was added, the resulting precipitate was collected [16] , and recrystallized from ethanol. Yield(85-92)% . symmetrical ( N,N-pyromellitamic diacid)[VI]: NN O S, N S CO2H HO2C OC CO HN NH R R R= , N S n= [VI]a,b,c,n CnH2n+1 2,4,7; NN O SH , To a solution of pyromellitic dianhydride (0.218g, 0.001mole) in (15mL) acetone, a solution of the amine (0.002 mole) in (15mL) acetone was added dropwise during one hour, the mixture was then left at room temperature with continuous stirring for (24 hours), the product was then filtered off and recrystallized from acetone or chloroform. The physical properties of these compounds are given in Table 1. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Symmetrical ( N,N-pyromellitdiimide)[VII] NN O S, N S R= , N S n=CnH2n+1 2,4,7; NN O SH , a,b,c,n NN O O O O R R [VII] A(0.01 mole) of N,N-pyromellitamic diacid was placed in (250 mL) round bottom flask, a mixture of anhydrous sodium acetate ( 0.02mole ) and acetic anhydride (15mL) was added. The mixture was maintained between(85-90) ◦C by means of a water -bath and stirred for half hour . The mixture was allowed to stir for one hour at room temperature . The mixture was poured on distilled water (400mL ) and worked out as specified in each case. The physical data of diimides[VII] are listed in Table (2). Elemental analysis of compound [VII]7 : Theoretical : C% = 62.82 , H% = 5.23 , N% = 10.99 Found : C% = 62.856 , H% =5.315 , N% =11.032 Carboxylic Acid Chlorides [VIII]b,c: was prepared following the procedure by Vogel [13]. R-COCl [VIII] R = CnH2n +1 ;n =4,7 b,c N,N-Bis-[4-(2-thioacyl-1,3,4-oxadiazole-5-yl)-phenyl]-pyromellitdiimid [IX]a-c NN NN O S C R O O O O R= C4H9 C7H15 OCH3 ,, [IX] O SCR O NN O To a stirred of compound [VII]C (0.568g, 0.001mol), triethy lamine (0.2g, 0.002mol) in dried mixture of (5ml DM F:10ml THF), was added dropwise carboxylic acid chloride [VIII] (0.001mol) at (0-4) 0C. After the addition had been completed the resulting suspension was stirred at the same temperature for 3hrs .The triethylaminhydrochloride salt was precipitate . It was filtered and the filtrate was poured with stirring into (100 mL) ice-water then the mixture was extracted by adding (50mL) of diethy l ether. Yield(77-90)% . IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Result and Discussion Ethyl amino benzoate [I] was obtained from esterification of the carboxylic acid moiety of 4-aminobenzoic acid by using absolute ethanol saturated with dry (HCI) gas .Condensation this ester [I] with hydrazide hydrate yielded the 4-amino phenyl hydrazide [II] , which is characterization by higher melting point and by FTIR–spectrum , revealed stretching vibration at 3237 cm -1 of N-H group as well as stretching absorption at 1632 cm- 1 due to C=O (amid) group. The reaction of acid hydrazide[II] with CS2 in KOH medium leads to the formation of thio-oxadiazole [III] by intramoleculer cyclization reaction . The structure of oxadiazole was confirmed by melting point and by spectroscopy . The FTIR-absorption spectrum showed the disappearance of absorption bands due to C=O (amid) and N-H groups of acid hydrazide together with the appearance of a stretching bands at 1630 cm -1, 1308 cm-1, 3102 cm-1 which are assigned to C=N, C=S and N-H groups, respectively of oxadiazole unit . It also shows stretching bands in the region (1050-1260)cm -1 due to (C-O-C) oxadiazole ring. 2-alkyl-thio-5-[4-aminophenyl]-1,3,4-oxadiazole [V]n were prepared by the reaction of 2-mercapto-oxadiazole with different n-alkyl bromides in basic medium. The structure of these compounds were identified by FTIR spectroscopy .The FTIR spectra of these compounds showed disappearance of the two peaks attributed to N-H and C=S stretching and appearance of many peaks in the region (2855-2967) cm -1 due to aliphatic C-H stretching. The amic acid [VI] were synthesized by the reaction of one mole of pyromellitic dianhydride with two moles of different amines in acetone as solvent. The mechanism involves nucleophilic addition reaction , as follows scheme (1). Scheme (1) OO O OO O NH2R Acetone C C C C N H H N O O R R H H C CO2HC HO2C HN NH O O R R R-NH2 Proton exchange [VI] O O O O The structure of these acids was studied by FTIR, UV-Vis and 1 HNMR spectroscopy. The FTIR absorption-spectra showed the disappearance of absorption bands due to NH2 and other peaks characterized of cyclic anhydride of the starting materials together with the appearance of new absorption stretching bands due to O-H of carboxylic moiety at (2500-3450)cm-1, C=O (carboxylic acid) at (1688-1716)cm-1 , C=O (amid) at (1645-1678)cm -1 and C=N (endocyclic) at (1609-1628)cm -1 of heterocyclic unit. The FTIR data of functional groups which are characteristic of the these new amic acid[VI]a-f and the UV-Vis data (λmax) are listed in Table 3. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 1HNMR spectrum of compound [VI]n=4 , showed the following characteristic chemical shift ( DM SO as a solvent) : A triplet band at δ 1.40-1.45ppm due to terminal methyl proton. Four protons mulitiplet at δ 1.69-1.97ppm that could be related to -CH2CH2- protons and two protons triplet at δ 3.23-3.27ppm due to SCH2 . A singlet signal at δ 4.77ppm for protons of N-H, eight aromatic protons appear as two doublets bands at δ 6.64-6.67ppm and δ7.58-7.61ppm. A good sharp signal at δ 7.94 ppm due to the two protons of centre aromatic ring. Finally, two protons of carboxylic moiety appear as a broad weak band at δ 12.8-14.1ppm. Pyromellitimides [VII]a-f were obtained by the intramolecular cyclization of amic acid [VI]a-f in acetic anhydride and sodium acetate at 85 0 C. The mechanism involves nucleophilic substitution reaction as follows of scheme (2). NN O OO O C CO2HC HO2C HN NH O O R R CH3CO2 CH3CO2 C C C C NH HN O O R R H3C C O O C O CH3 C C O O HN NH O O R RC C H3C CH3 O O O O (80-90)0C RR Scheme (2) [VII] Na Na 2CH3CO2H H3C C O O C O CH3 O O O O NHNH O O O O O C CH3 O OCH3C O R R The structure of these compounds was studied by FTIR, UV-Vis and 1 HNMR spectroscopy. The FTIR spectra exhibited significant two peaks in region (1700-1800)cm -1 which could be attributed to stretching vibration of the carbonyl of the (imide cyclic) and two absorption bands around 1180cm -1 and 775cm-1 for asym. and sym. of C-N-C (cyclic). They also show the disappearance of absorption stretching bands of N-H , O-H and C=O (carboxylic moiety) groups of amic acid. The FTIR absorption bands data of these compounds[VII]a-f and the UV-Vis data (λmax ) are listed in Table (4). 1HNMR spectrum of pyromellitdiimide [VII]c, (DM SO as a solvent) showed a good peak at δ 2.69 ppm due to S-H group, eight aromatic protons of (AB) which are typical for p-disubstituted benzene appear as two doublets at δ 7.80-7.91 ppm [17] . A singlet signal at δ 7.95ppm for two protons of centre benzene ring and a sharp single at δ 10.38 ppm due to N-H group. Elemental analysis result of compound [VII]7 is in good agreement with the theoretical data . N,N-Bis-[4-(2-thioacyl-1,3,4-oxadiazole-5-yl)-phenyl] pyromellitdi-imid [IX]a-c synthesized by the reaction of [VII]c with acid chloride[VIII]a-c in mixture of (DMF+THF) in the basic medium Et3N.The FTIR spectra showed a good peak at (1686-1715) cm-1 due to C=O thioester . The FTIR data of thioester [IX]a-c showed in Table 4. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 References 1. Sharma ,P.; Kukreja , P.;Choudhary,V. and Narula , A. (2005) "Curing and Thermal Behaviour of Epoxy Resin in The Presence of Oromatic Imide –Amines", Ind. J. of Engin. and Mat. Sci. of Chem., 12: 259-264. 2. Lee , S.;Shin,G.; Chi,J.; Zin,W.; Jung , J.;Hahm ,S.; Ree , M. and Chang ,T. (2006) "Synthesis , characterization and liquid-crystal-aligning properties of novel aromatic polypyromellitimides bearing (n-alkyloxy) biphenyloxy side chains", Polymer, 47: 6606-6621. 3. Mathews , A.; Kim , I. and Ha ,C. (2007) " Synthesis, Characterization, and Properties of Fully Aliphatic Polyimides", M acromolecular Research, 15(2): 114-128. 4. Hoogenboom , R. and Schubert ,U. (2007) "Microwave-Assisted Polymer Synthesis : Recent Developments in a Rapidly Expanding Field of Research", Macromol. Rapid Commun., 28: 368–386. 5. Zheng ,Q.; Huang ,J.; Sarjeant , A. and Howard, E. Katz (2008) "Pyromellitic Di- imide Minimal Cores for High Mobility", J. AM. CHEM. SOC. 130: 410-411. 6. Darshan , Malhota , P. and Narula, K. (2009) "Effect of Structure of Diamide-Di- imide-Diamines Based on L-methionine on Curing Behavour and Thermal Stability of DGEBA", Ind. J. of Chem.,48B: 893-903. 7. Mallakpour ,Sh. and Rafiee ,Z. (2008) "Application of Microwave-assisted Reactions in Step-growth Polymerization: A Review", Iran. Polym. J.17(12):907-935. 8. Liu , P. (2005) "Preparation and Characterizations of Poly(amic acid) Grafted Silica Nanoparticles", Iran. Polym. J., l 14(11): 968-972. 9. Lucero, D.; Likhanova , N.; Hopfl , H.; Guzman , J.; Likhatchev, D. and Palou , R. ( 2006), " Efficient microwave-assisted synthesis of bisimides", General Papers ARKIVOC,(x), 7-20. 10. Faghihi , K.; Shabanian , M. and Hajibevgi , M. (2009) "Optically Active and Organosoluble Poly(amide-imide)s Derived from N,N'-(Pyromellitoy l)bis-L- histidine", Macromo. Res. ,17(11): 912-918. 11. Zahmatkesh , S. and Vakili , M. (2010) "Synthesis and Characterization of New Optically Active Poly (ethy l L-lysinamide)s and Poly (ethy l L-lysinimide)s", J. of Amino Acids ,1:1-6. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 12. Sato,Y.; Yoshida , M. and Ando , S. (2006) "Optical Properties of Rod-like Fluorinated Polyimides and Model Compounds Derived from Diamines having High Electro -donating Properties", J. of Photopolymer Sci. and Technology, 19(2): 297- 304. 13. A. I. Vogel , Practical , (1974),"Organic Chem., Longman Group Ltd.,Londdon, 3 rd Edition . 14. Atto, A.; Mohamed, M. and Hameed , A. (2000) "Synthesis , Spectroscopy and study of Some New 1,3,4-O xadiazole Derivatives, Iraqi J. Chem., 26(1) : 86-93. 15. Tomma , J.;Al-Mehdawy, M.; Mubbrik , S. and Al-Dujaili , A. (2004) "Synthesis Antibacterial Activity of Some New Schiff Bases containing 1,3,4-Oxadiazole Ring", Iraqi J. Sci., 45(1) : 39-45. 16. Tomma , J. and Al-Dujili , A. (2002) "M esomorphic Behaviour of Some New Schiff Base Esters Containing 1,3,4-Oxadiazole Unit ", 43(1): 35-57. 17. Tomma, j. (2001) "Synthesis Characterization and Investigation Effect of Chemical Constitution of Liquid-Crystalline Monomers , Dimers and Polymers. Table (1) The physical properties of symmetrical diamic acid [VI]a-[VI]7 Co m.N o. Nomenclature Structural formula Molecular formula M.P ◦C Yiel d% Color [VI] a N,N—-Bis-(2-thiazole)- pyromellitamic diacid CO 2 H HO2C N S N S HN NH O O C16H10N4O6S 2 >30 0 89 white [VI] b N,N — -Bis-(2- benzothiazole) - pyromellitamic diacid. CO2H H O2C C C O NH O HN S N N S C24H14N4O6S 2 >30 0 91 white [VI] c N,N—-Bis-[4-(5-phenyl)- 2-thio-1,3,4-oxadiazole - pyromellitamic diacid. CO2HC HO2C C O HN O NH NN O NN O HS SH C26H16N6O8S 2 >30 0 96 orang e [VI] 2 N,N—-Bis-[4-(2-ethylthio- 1,3,4-oxadiazole-5-yl)- phenyl] pyromellitamic diacid. C CO2HC HO2C O O NH HN NN O NN O S SC4H9 C4H9 C30H24N6O8S 2 >30 0 89 Orange [VI] 4 N,N—-Bis-[4-(2- butylthio-1,3,4- oxadiazole-5-yl)phenyl]- pyromellitamic diacid . CO2 H CO OC HO 2C HN NH NN O S C4H9 NN O SC4 H9 C34H32N6O8S 2 276- 278 90 Orange [VI] 7 N,N—-Bis-[4-(2- heptylthio-1,3,4- oxadiazole-5-yl)-phenyl]- pyromellitamic diacid. CO2H HO2C NN O SC7H15 NN O S C7HNH HN O O C40H44N6O8S 2 238 88 Yellow IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Table (2):The physical properties of symmetrical pyromellitdiimide [VII]a-c,n and [IX]a-c. Co m.N o. Nomenclature Structural formula Molecular formula M.P◦ C Yiel d% Colo r [VII ]a N,N — -Bis-(2- thiazole)- pyromellitdiimide NN N S N S O O O O C16H6N4O4 S2 198- 200 78 Pale yellow [VII ]b N,N—-Bis-(2- benzothiazole)- pyromellitdiimide NN N SS N O O OO C24H10N4O 4S2 >300 90 yellow [VII ]c N,N—-Bis-{[4-(2-thio- 1,3,4-oxadiazole)-5- yl]-phenyl} – pyromellitdiimid. NN O O O O NN O HS NN O SH C26H12N6O 6S2 182- 184 92 Pale yellow [VII ]2 N,N—-Bis-[4-(2- ethylthio-1,3,4- oxadiazole-5-yl)- phen- yl] - pyromellitdiimide. NN NN O NN O SC2H5 C2H5S O OO O C30H20N6O 6S2 160- 162 85 orange [VII ]4 N,N — -Bis-[4-(2- butylthio-1,3,4- oxadiazole-5-yl) phenyl]- pyromellitdiimide. NN O O O O NN O NN O S S C4H9C4H9 C34H28N6O 6S2 138- 140 88 Pale yellow [VII ]7 N,N—-Bis-[4-(2- heptylthio-1,3,4- oxadiazole-5- yl)phenyl] - pyromellitdiimide NN NN O SC7H 15 O O O O NN O C7H15 C40H40N6O 6S2 92-94 75 Yello w [IX] a N,N-Bis-[4(2-thio-4- (methoxyphenyloxy- 5-yl)-phenyl]- pyromellitdiimide NN NN O NN O S S CC O O O O H3CO O CH3 OO C42H24N6O 10S2 oily 80 yellow [IX] b N,N-Bis-[4-(2-thio- pentyloxy-1,3,4- oxadiazole-5-yl)- phenyl ] - pyromellitdiimide NN NN O NN O S S CC C4H9 C4H9 O O O O OO C36H28N6O 8S2 oily 77 Brown [IX] c N,N-Bis-[4(2-thio- heptyloxy-1,3,4- oxadiazole-5-yl)- phenyl ]- pyromellitdiimide NN NN O NN O S S CC C7H 15 C7H15 O O O O O O C42H40N6O 8S2 Crysta l Gum my 90 yellow IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Table(3):Characteristic FTIR absorption bands and UV data (λmax) of compounds [VI]a- Comp .No. λma (nm) V N- H VO-H VC-H aromatic VC-H aliphatic VC=O carboxylic VC= O amid VC=N endocyclic VC=C aromatic [VI]a 266 3302 3450- 2400 3113 1695 1659 1616 1580 [VI]b 264 3289 3200- 2450 3115 1688 1655 1628 1591 [VI]c 318 3352 3450- 2500 3103 1709 1678 1625 1607 [VI]2 306 3368 3400- 2400 3086 2967- 2855 1709 1670 1609 1587 [VI]4 300. 5 3350 3435- 2450 3077 2957- 2860 1716 1645 1609 1582 [VI]7 304 3348 3250- 2500 3075 2955- 2855 1710 1645 1609 1589 IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (3) 2011 Table(4):Characteristic FTIR absorption bands and UV data (λmax) of compounds [VII]a-c,n and [IX]a-c Com p.No. λmax(n m) VC-H arom. VC-H alipha. VC=O Imides Cyclic asym.,sym VC=N endocycl ic VC=C aromati c VC-N-C asym.,sym . Other [VII]a 268 3113 1800,1728 1685 1600 1172,779 [VII] b 250 3113 1787,1740 1634 1597 1195,772 [VII]c 302 3100 1728,1695 1622 1591 1180,760 VN-H at 3337 VC=S at 1317 [VII] 2 302.5 3100 2960- 2850 1740,1701 1605 1576 1179,775 [VII] 4 300 3110 2955- 2868 1736,1700 1607 1578 1182,765 [VII] 7 300 3051 2955- 2865 1740,1710 1601 1570 1175,768 [IX]a 310 3080 2959- 2859 1728,1700 1640 1606 1165,779 VC=0 thioester 1710 [IX]b 306.5 3100 2989- 2872 1724,1701 1645 1610 1175,780 VC=0 thioester 1715 [IX]c 315 3080 2959- 2872 1740,1710 1640 1607 1171,774 VC=0 thioester 1686 للعلوم الصرفة والتطبیقیة 2011) 3( 24المجلد مجلة ابن الھیثم وحوامض یمیدثنائي اال لبایروملیتل تحضیر وتشخیص مشتقات جدیدة متماثلة االمیك لها جمبد هرمز توما ، العلیاوي كاظم ماذي الزم ، عماد تقي علي جامعة بغداد، ابن الهیثم-كلیة التربیة، قسم الكیمیاء 2011آذار 29 :استلم البحث في 2011آیار 30: قبل البحث في الخالصة من ثنائي انهدرید ، خطوتین يعن طریق تفاعل ذ [VII]یمید اال ةثنائی تمیلحضرت مركبات البایرو ةمختلف أمیناتحضرت حوامض االمیك الجدیدة من تفاعل ثنائي انهدرید البایرومیلیتك مع ، اذ المقابل البایرومیلیتك ضمني ال حلقيالغلق التضمن خطوة التفاعل الثاني بینما ت. "مذیبا ن الجافاالسیتو باستعمالتحتوي حلقة غیر متجانسة (90-80)حرارةوبدرجة خالت الصودیوم- حامض االمیك بوجود انهدرید الخلیك لجزیئة 0 C . -UV وأطیاف وتحلیل العناصر درجات انصهارها قیاس طةات صحة تراكیب المركبات المحضرة بوستاثب Vis 1HNMR , FTIR : لها . حامض البایرمیلتامیك ,بایرومیلیتیك ثنائي االنهدرید , یمید ثنائي اال بایرومیلیت : الكلمات المفتاحیة