Microsoft Word - 200-216 Chemistry | 200 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 Synthesis and Spectral Characterization of Some New Aromatic Schiff Bases Derivated from 2,4- Dinitrophenylhydrazine Anwar Th. Mahmood Noor A. Khudhair Dept. of Chemistry/ Collage of Science/ University of Baghdad Received in: 29/December/2015,Accepted in:31/January/2016 Abstract Four novel Schiff bases SB1 to SB4 as new aromatic compound not hydrolysed under ordinary conditions were synthesized in this study by condensation reactions between2,4- dinitrophenylhydrazine: firstly with 2,4,4`-trihydroxybenzophenone to give SB1, secondly with 4- hydroxybenzophenone to give SB2, thirdly with 4-dimethylaminobenzaldhyde to give SB3 and fourthly with 4-aminobenzaldehyde to give SB4. The molecular structures of these aromatic Schiff bases obtained were identified and characterized based on melting points, elemental analysis(CHN), FT-IR and UV-Visible spectra. The electronic absorption spectra of Schiff bases obtained were studied in the solvents of ethanol, DMF, water, chloroform, carbon tetrachloride and cyclohexane. The recorded absorption bands in ethanol solvent were assigned to corresponding electronic transitions were discussed. The absorption bands at 291 to 411 nm obtained in electronic spectra of the synthesized new aromatic Schiff bases were assigned to (π→π*) transition which originates from substituted benzophenone or benzaldehyde rings and directed along of molecule in Schiff bases. These transitions are assumed to represent the intramolecular charge-transfer complexes bands in which the substituted two moieties of benzophenone and benzaldehyde rings are the charge donors and the substituted phenylhydrazine ring is the charge acceptor. Also, the effect of polar, non-polar solvents on the electronic transitions of charge-transfer bands have measured and discussed. The physical-spectroscopic parameters in molecular structural shapes of intra CT complexes molecules such as transition energies, molar extinction coefficients, molecular oscillate strength; transition molecular dipole moment and molecular resonance have been calculated and discussed. Key word: Schiff base, charge-transfer complexes, FT-IR, CHN, UV-Visible Chemistry | 201 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 1. Introduction. Schiff bases are an important species of organic compounds. Which where prepared in 1864 by a German chemist, Hugo Schiff, Nobel prize winner [1]. These compounds are produced from condensation of primary amines or hydrazine compounds with carbonyl compounds such as aldehydes or ketones. Structurally, Schiff base which also known as azomethine or imine compound in addition to hydrazone class is an analogue of aldehyde or ketone of aldehyde or ketone in which the carbonyl group will be replaced by an imine group (-CH=N- or C=N-) [2,3]. The preparation of Schiff bases are reversible reactions and take place under acid catalysis or by direct fusion [4-6]. In recent years, Schiff bases have been shown to a wide range of biological activity, including antibacterial, antifungal, antiviral, anticancer, antimonial, antiprotiferate, anti-inflammatory, antipyretic and Biocidal properties [7-11]. The azomethine and hydrazone group (-CH=N-NH- or C=N-NH-) in Schiff bases have been shown to be decisive to their biological activities [12,13]. Schiff bases are a set of organic intermediates which are used also in the synthesis and chemical analysis. They are used in the production of the drugs and agrochemical industry. The transition elements and the other certain metallo-elements are known to from aromatic Schiff bases complexes [14,15]. Aromatic Schiff bases behave as flexi-dentate ligands and ordinarily coordinate through nitrogen atom of imine group, oxygen atom of the de-pronated phenolic group and other donor atoms [16]. Charge-transfer complexes of Schiff bases are great importance in chemical interaction, including intramolecular charge-transfer complexes, biochemical and bioelectrochemical energy transfer processes, biological systems, drugs- acceptors binding mechanisms and drugs analysis [17-20]. Moreover, charge-transfer complexations are of great importance in many applications and fields, such as electrical conductivities of materials, optical activities, surface chemistry, solar energy storage, semiconductors and investigations of redox processes [21-23].based on this, we decided preparation new aromatic Schiff bases are not hydrolysed under ordinary condition and derived from 2,4,4`- trihydroxybenzophenone, p-hydroxybenzophenone, p-dimethylaminobenzaldehyde and p- aminobenzaldehyde with 2,4-dinitrophenylhydrazine may fit-those purpose, then identification of molecular structures by elemental analysis and spectra of IR, and UV- Visible. The study also includes explanation of electronic transition, determination of the physical spectroscopic parameters. 2. Experimental 2.1 Chemical Materials All of the chemicals used were of high purity degree and were used without purification. The solvents of ethanol and methanol were used of Analar grade and supplied by Fluka Company, while the solvents of cyclohexane, carbon, tetrachloride, chloroform and dimethylformamide were of Spectroscopic grade which were supplied by BDH Company. Organic compounds of 4-hydroxybenzophenone (98% purity grade) and 2,4- dinitrophenylhydrazine (99% purity grade) were supplied by Merck Company, 4- Aminobenzaldehyde and 4-dimethylaminobenzaldehyde (99% purity grade) were supplied by BDH Company, while 2,4,4`-trihydroxybenzophenone (98% purity grade) was supplied by INC Company. Chemistry | 202 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 2.2 Instruments Melting points were recorded using Gallenkamp melting points apparatus which measures the extent to 280˚C. The elemental analyses of the carbon, hydrogen and nitrogen contents were determined using a Perkin-Elmer CHN 2400 (USA). FT-IR spectra data were obtained by Shimadzu-8400S- FT-IR Spectrophotometer in the wave number range of 4000-400 cm-1 which included in KBr discs. The electronic absorption spectra were recorded in different solvents and media over wavelength range of 190-900nm by the Varian DMS 100 UV-Visible double-beam spectrophotometer which linked thermostaticall controlled unit. The instrument was equipped with a quartz cell of path length 1.0cm. 2.3 Synthesis of Schiff Bases. Four aromatic Schiff bases were prepared as follows: (1) Schiff bases SB1 was prepared by mixing equimolar amounts (0.05 mol) of 2,4-dinitrophenylhydrazine (0.9909gm, m.p. 197- 200 ˚C) and 2,4,4`-trihydroxybenzophenone (0.1512gm, m.p. 196-197˚C), both dissolved in 25 ml ethanol solvent then added (2-3) drops of concentrated HCl (36%). The reaction mixture was heated under back reflux for 8 hour, after cooling maroon crystals product was separated, then filtered. The solid product was crystallized by ethanol, then dried. Melting point of SB1 was recorded higher than 280˚C. Schiff bases SB2 prepared by mixing equimolar amounts of 2,4-dinitrophenylhydrazine (0.9907gm) and 4-hydroxybenzophenone (0.9911gm, m.p. 110-112˚C), both dissolved in 25 ml ethanol solvent and added (2-3) drops of concentrated HCl (36%). The reaction mixture heated under back reflux for two hour, after cooling orange precipitate was separated, then filtered. The solid precipitate was recrystallized by ethanol, and then dried. Melting point of SB2 was recorded 218-220˚C. Schiff base SB3 prepared by mixing equimolar amounts ofand 2,4-dinitrophenylhydrazine (0.991gm) and 4- dimethylaminobenzaldehyde (0.736gm, m.p. 73-75˚C), both dissolved in 30 ml methanol solvent and then added (3) drops nearly of concentrated HCl (36%). The reaction mixture heated under back reflux for 1 hour, after cooling black precipitate was separated in solution, and then filtered. The black precipitate was crystallized by methanol, then dried. Melting point of SB3 was recorded than 235-237˚C. Schiff bases SB4 was prepared by mixing equimolar amounts of 2,4-dinitrophenylhydrazine (0.9911gm) and 4-amiobezaldehyde (0.6061 gm, m.p. 165-168˚C), both dissolved in 30 ml methanol solvent and added (3) drops of concentrated HCl (36%). The reaction mixture heated under back reflux for 2 hour, after cooling black brown precipitate was separated in solution, then filtered and washed by cyclohexane.. The black brown precipitate was recrystallized by methanol, and then dried. Melting point of SB4 was recorded higher than 184-186˚C.The molecular structures of these Schiff bases characterized and identified by their melting points, elemental analysis (CHN) and spectra of FT-IR and UV-Visible. 2.4 Preparation of Samples Solutions. Standard solutions were prepared for spectral measurements of the materials that included in this study from 2,4-dinitrophenylhydrazine, aromatic carbonyls derivatives and the prepared new aromatic Schiff bases in gravimetric method. We weight the required amount from solute substance in certain volume of proper solvent in volumetric flask to prepare standard stock solution, than prepare different concentrations for spectral measurement in UV-Visible spectroscopy in dilution method from standard solution. Chemistry | 203 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 3. Results and Discussion 3.1 Chemistry and Characterization. New Schiff bases have been synthesized from the condensation 2,4-dinitrophenylhydrazine with2,4,4`-trihydroxybenzophenone,4–hydroxybenzophenone, 4-dimethylaminobenzaldehyde and 4-aminobenzaldehyde(Scheme(1)). They are stable at room temperature and commonly soluble in methanol, ethanol, water and DMF. The elemental analysis (CHN), yield percentage physical state, color and melting point of these Schiff bases SB1-SB4 are presented in Table(1). 3.2 Melting Points. From melting points in Table(1), it is expected that there in Schiff base SB1 both inter- and intramolecular hydrogen bonds because of three hydroxyl groups in ortho- and para- positions on the phenyl groups. It is known that intermolecular hydrogen bonding increase the melting point of the organic compounds [24]. Also, the melting point of the Schiff bases SB1, SB2 and SB3 , ˃280, 218 and 235˚C respectively, are higher than Schiff base SB4. However, melting point of Schiff base SB4 is lower (184˚C) than Schiff base SB1which includes intra- and intermolecular hydrogen bonding. Some substituted aromatic Schiff bases exhibit the ketamine tautomeric shapes and their common feature which is the presence of the substituted hydroxyl or amino group on the aromatic ring [24]. The low melting point of Schiff base SB4 may be explained by (I) and (II) tautomerism shapes as shown below: H2N C H N H N O2N NO2 HN H2 C H N H N O2N NO2 (I) (II) 3.3 FT-Infrared Spectra. The relevantFT-IR spectral absorption bands that can provide the identification structural evidences as FT-IR spectral data (from KBr disks) of the synthesized new aromatic Schiff bases are shown in Table(2), which are recorded as characteristic bands wave numbers (cm-1) data from FT-IR spectra of the Figures 1to 4. The FT-IR spectra of these Schiff bases show very strong or strong intensity of absorption bands at 1607-1635cm-1 assigned to stretching vibration of azomethine bond (υC=N) which are as follows: 1614, 1014, 1607 and 1635cm-1 attributable to SB1to SB4 respectively[24, 25]. The presence of aromatic rings has been identified by their characteristic aromatic ring vibration at (1400-1500), (1050-1100) and (700-900) cm-1 regions, including the bending vibration bands of C-N bond (ɤC-N) which are (1055, 1097), (1051, 1086, 1078 and 1018 cm-1 assigned to SB1to SB4 respectively. The stretching vibration bands at 1275cm-1 attributable to vibration of C-O bond (υC-O)in SB1and SB2 [24-26]. The absence of absorption bands characteristic of C=O bond (υC=O) and primary amine (υN-H) confirm the formation of the synthesized new aromatic Schiff bases framework, accept N-H bond in SB4. The stretching vibration bands of C-H bond in (υC-H) IN –CH=N- group appear at 3090 and 2966cm-1 for SB3 and SB4 respectively, while stretching vibration band of NO2 group appear at 1512, 1510, 1512 and 1529cm-1 as strong intensities in SB1, SB2, SB3 and SB4 spectra, respectively. The strong intensities absorption bands at 1337, 1335, 1325 and 1350cm-1 attributable to the stretching vibration bands of N-N bond (υN-N). The band at 3070cm-1in the spectrum SB1 (Figure1) shows the OH….N intramolecular hydrogen bond between proton of hydroxyl group in ortho- position and nitrogen atom [24, 25]. Also,the broad band at 3454 and 3421cm-1 attributable to hydroxyl group bonded by Chemistry | 204 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 intermolecular hydrogen bonding in SB1 and SB2 respectively, while the broad band at 3138cm-1 attributable to primary amine bonded by intermolecular hydrogen bonding. The stretching vibration band with strong intensity at 3277cm-1 is attributable to C-H bond of methyl group in SB3 in Figure (3) [25, 26]. 3.4 Electronic Spectra and Their Explanation. Figure (5) to (8) represent the electronic spectra of the synthesized new aromatic Schiff bases which contain substituted phenyl rings with hydroxyl, dimethylamino, amino or nitro and azomethine groups. Table (3) shows all the absorption bands of electronic transition. These absorption bands can be explained as follows: The absorption band at 198, 197, 201 and 201nm in the electronic spectra of SB1 to SB4 respectively, all these represent the local excitations (π → π*) transitions of the substituted phenyl rings, which correspond the transition (1A1g → 1E1u) at 184nm of benzene ring [6, 25, 27], and support that in this work absorption intensities of these bands decrease for their values compared with the intensity value at 184nm (6000 m2.mol-1) of benzene ring [25]. This can be explained due to azomethine and nitro groups presence which do as electron-withdrawing groups and cause an inductive effect in each of SB1 to SB4, hence decreases the transition intensities on the aromatic substituted phenyl rings [6, 25]. The absorption bands 207, 217 and 222 nm all shoulders in electronic spectra of SB1, SB2 and SB4 respectively represent the local excitations (π→π*) transitions of substituted phenyl rings which correspond to the electronic transition (1A1g → 1B1u) at 203nm of benzene ring [25]. We think that the absorption bands for this transition in SB3 did not appears because its intensity can be submerged under B-band or /and K-band [25, 27]. The absorption bands at 224, 244, 241 and 242nm as shoulder in the electronic spectra of Schiff bases SB1 to SB4 respectively, represent the local excitations (π → π*) transitions of substituted phenyl rings which correspond the electronic transition (1A1g → 1B2u) at 256nm of benzene molecule [6, 25], while the bands at (298, 293), (291, 385), (314, 411) and (320, 406) nm in electronic spectra of SB1 to SB4 respectively, all these bands represent (π→ π*) transitions which are originated from substituted groups as electron- donating groups on carbonylic ring, and extended over the whole Schiff bases molecule to substitute to nitro groups as electron-withdrawing groups on the hydrazine phenyl rings. The presence of one or more hydroxyl group in the ortho or para position or both and dimethylamino or amino group at the para position in the Schiff base molecule enhances such transition [25, 27]. Theses absorption bands can suggest there is due to intramolecular charge transfer effect of the formed molecular chromophore which includes electron donor part and electron acceptor part within the same molecule of Schiff base. These intracharge-transfer states are similar to the intracharge-transfer in p-nitroaniline molecule which absorbs the light at 376nm as follows [27, 28]: NH2N O O NH3N O O h Molecular chromophore (CTC) which absorbs the at 376 nm.   3.5 Spectroscopic-Physical Parameters of Infra CT Complexes. The spectroscopic and physical parameters of intracharge-transfer complexes in SB1 to SB4, such as transition energy (hυCT), molar extinction coefficient (εCT),the molecular oscillate strength (ƒCT), transition molecular dipole moment(μCT), resonance energy (ER) in the molecular structure shape of intracharge-transfer complex molecule. These parameters were calculated and inserted in Table (4) for SB1 to SB4 dissolved in ethanol solvent at 20oC. All values have been appointed by charge-transfer band with least energy in the electronic spectra of SB1-SB4 as shown in the figures (5) to (8). The transition energy of the (π → π*) Chemistry | 205 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 transition at intracharge-transfer band was calculated using the conversion factor between the energy by electron volt unit (eV) and wavelength (λCT) by nanometer (nm) as shown in equation(1). hυCT(eV) = 1240.8 (nm. eV) / λmax(nm) (1) The molecular oscillate strength at excited state of the intracharge-transfer complex molecule has been estimated using approximate formula by equation (2) [29 and 30]. ƒCT = 4.319 x 10-9 ԐCT . ∆ῡ1/2 (2) Where ∆ῡ1/2 is the half band width and ԐCT is the extinction coefficient. The value (4.319*10-9) in equation (1) is number without units. When units of ԐCT and ∆ῡ1/2 are (l.mol- 1.cm-1) and (cm-1) respectively, the units of ƒCT in equation (2) becomes (l.mol-1.cm-2). The molecular oscillator strength represents quantitative measurement of a dimensionless used to express the electronic charge-transfer probability from HOMO of electron donor part to LUMO of electron acceptor part within the molecular structure of intracharge-transfer complex molecule [31, 32].The transition molecular dipole moment at excited state of the intracharge-transfer complex molecule has been calculated by the equation (3)   Where ῡCT is the wave number of charge-transfer band. The value 9.582*10-2 is constant by unit (Debye. l 1/2. mol1/2. cm1/2). When the values units of ԐCT (l.cm-1.mol-1), ῡCT (cm-1) and ∆ῡ1/2 (cm-1),the unit of µCTbecomes(Debye).value of transition molecular dipole moment reflects quantitative measurement for the intracharge-transfer overlap range and the direction which gives the polarization of the transition, in addition to determine how the molecular system will interact with an electromagnetic wave, while the square of the value (µ2CT) reflects the strength of the interaction due to the distribution of charge within the structure of molecular chromophore [27, 28]. The molecular resonance energy at ground state of the intramolecular charge-transfer complex molecule in has been estimated by the theoretical equation (4) [33]. ER = h CT .  CT 7.7x 10-4 + ( 3.5 CT ) (4) Where value (7.7*10-4) is the same unit of ԐCT, while the value (3.5) is number without units. When unit of (hυCT) is electron volt, the unit of ER in equation (4) becomes (eV). Molecular resonance energy valuereflects obviously as contributing factor to stability of the molecular chromophores of intramolecular charge-transfer complex molecule [28]. Returning to Table (4), the values of the (μCT) and (ER) reflect the relative stability of intracharge-transfer complexes molecules and these values increase with increasing the stability of the molecular chromophores shapes for Schiff bases molecules from SB1to SB2, as well as from SB3 to SB4 except molecular resonance energy (ER) value of SB3 is less. The stability of Schiff base SB3 is less compared with Schiff base SB4 due to the steric hindrance effect of dimethyl groups with unshared-pair of electrons on nitrogen atom [25]. The results of the(hυCT) and (ԐCT)agree well with the values of (ER) and (μCT).This agreement support the explanation provided. The relative high values of (ƒCT) and (μCT) for intramolecular charge-transfer complexes in Schiff bases SB1,SB2 and SB4 suggested the formation of inner sphere complexes (D+→A−) in the excited state, while lower values for SB3 suggested the formation of outer sphere complex (D+δ→A−δ) in excited state [34]. Scheme (3) shows molecular structures of intramolecular charge-transfer complexes of SB1 to SB4, which can be responsible for light absorption, and the values of physical parameters (ƒCT, μCT, ER). Chemistry | 206 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 3.6 Effect of Solvent Polarity on the Electronic Transitions Table (5) shows nonpolar solvent effect (cyclohexane, carbon tetrachloride and chloroform) on absorption bands in electronic spectra of SB1-SB4, Table (6) shows polar solvent effect (ethanol, dimethylformamide and water). Clearly, the data seem that the polar and nonpolar solvents did not affect the absorption band at 193-263nm in the electronic spectra of SB1 to SB4, but there is marked effect on the longer wavelength absorption bands than 285 nm. Table (7) shows such effects and Figures (9) to (12) illustrate that the red shift (∆ῡ) in λmax for longest wavelength absorption band of SB1-SB4. The red shift increases rapidly with increasing dielectric constant of the solvent until the value (50) nearly for SB1, (30) for SB2, (10) for SB3, and (24.33) for SB4, after that the increase becomes gradual to the value of water 76.5. The increase of red shift (∆ῡ) with dielectric constant of solvent may explained as follows: After absorption light, the excited state of Schiff base molecule becomes more polarthan its ground state, therefore the polar solvent stabilizes the excited state by connecting dipole of Schiff base molecule with positive and negative ends of the solvent molecules. The more delocalization of the charge in the excited state of Schiff base molecule, higher increase of red shift (∆ῡ) with dielectric constant occurs. This effect is very clear in the all cases of SB1-SB4.In these molecules there are hydroxyl, amino and dimethylamino groups which increase the delocalization of the charge in Schiff base molecule and leading to higher values of red Shift.Scheme(4) shows excited molecular shapes of intramolecular charge-transfer complexes and their CT bands in different solvents. 4. Conclusion In recent years, considerable attentions has been devoted to the formation stable intra- and intermolecular charge-transfer complexes which consist within aromatic Schiff bases as drugs, biological activity compounds or semiconductors, in addition to numerous of other important applications. This interest stems from significant physical and chemical properties of these compounds. 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Bull., 56(19), 1993-2000. 32- Refat, M. S.(2011) ; Spectroscopic and Thermal Investigations of Charge-Transfer Complexes formed Between Sulfadoxine Drug and Different Types of Acceptor; J. mol. Struct. 985(2,3), 380-390. 33- Briegleb, G.; Czekalla, and physikchem(1960); Electron Donor-Acceptor Complex; J. Frankfunt, 24, 237-244. 34- Anwar, T. M. and Ahmed, T. B.(2013) ; Physical-Spectroscopic Study of Charge- Transfer Complexes of Some Purine Derivatives with (π) and (δ) Electron Acceptor; Iraqi J. Sci., 54(4), 994-102. Chemistry | 209 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 Table(1): Physical characterization and elemental analysis CHN data of new Schiff bases SB1 – SB4. Schiff base formula and 1 – M.wt /g.mol Physical state and (Color) % Yield C)º(m.p / CHN Elements analysis (Calculated) C% H% N% 1SB 7O4N14H19C 410.36 Crystals (maroon) 87 (˃280) 55.56 (55.61) 3.35 (3.41) 13.70 (13.66) 2SB 5O4N14H19C 378.36 Crystals ( orange) 85 (218–220) 60.38 (60.32) 3.65 (3.70) 14.75 (14.81) 3SB 4O5N15H15C 329.33 Crystals ( black) 76 (235–237) 54.64 (54.71) 4.50 (4.56) 21.35 (21.28) SB4 C13H11N5O4 301.28 Crystal (black brown) 91 (184–186) 51.69 (51.83) 3.58 (3.65) 22.99 (23.26) Table (2): Characterization infrared band frequencies (cm-1) data for prepared Schiff bases (SB1 - SB4). υ: streching vib. , ɤ: bending vib. , br. : broad S. : Strong, m. : medium, vs..: very strong. Table (3): Electronic spectra bands data of the prepared aromatic Schiff bases in ethanol solvents at temperature 20ºC. Aromatic Schiff base λ max / nm (Ԑ / m 2 . mol-1 ) SB1 198 (3620 ± 90) sh. 207(3250±70) sh.244(1750± 60) sh.298(910±30) 395 (2190±40) SB2 197 (3880 ± 100) sh.217 (2480±50) sh.244(1890±70) sh. 291(920±40) 385 (2830 ± 80) SB3 201 (430 ± 30) sh.241(120±10) 314(120±5) 411 (220 ± 10) SB4 200 (3020 ± 110) sh.222 (2360±90) sh.242 (1790±60) sh.330(1360±20) 406 (2490 ± 30) λmax: wavelength of absorption maximum, Ԑ: Extinction coefficient and sh. : shoulder. Schif f base υ(O-H), υ(=CH)*, υ(N-H)**,υ(CH)*** υ(C=N) ɤ(C-N) with ring υ(NO2) ɤ(N-N) υ(C-O) with ring Aromatic ring vibration H-bonding in the IR spectra SB1 3485s. 3454 br.m.bonded. 3070 br.m.bonded. 1614vs. 1055m. 1097m. 1512s. 1337s. 1275s. 702m. 743s. 833s. 866s. 919s. 962s. 1418s. 1458w. Intra and inter H-bonding SB2 3477s. 3421br.m. bonded. 1614vs. 1051w. 1086s. 1510s. 1335s. 1275s. 700s. 743m. 779m. 831s. 918m. 966w. 1420s. Inter H-bonding SB3 3090 m. * 3277 *** 1607vs. 1078w. 1512s. 1325s. ------- 708m. 743s. 820s. 903w. 926m. 946s. 1414s. 1447m. -------- SB4 3308 vs. * 3138 br.s.bonded** 2966w. 1636s . 1018m. 1530s . 1350s . ------- 837s. 995m. 1450s. Inter H- bonding Chemistry | 210 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 Table (4): The values of transition energy, oscillate strength and values of transition dipole moment of intramolecular CT complexes for the synthesized aromatic Schiff bases SB1- SB4 in ethanol solvent and temperature 20ºC. Aromatic Schiff bases λmax/nm hυCT/ eV ԐCT / dm3.mol-1. cm-1 ∆ῡ½/ cm -1 ƒCT/(cm. molecule-1*1022) µCT/ Debye ER/ eV SB1 395 3.141 21923 7207 1.134 7.570 0.897 SB2 385 3.223 28323 6156 1.251 7.851 0.921 SB3 411 3.019 2223 8143 0.130 2.614 0.863 SB4 406 3.056 24852 6956 1.241 8.029 0.873 Table (5):The non-polar solvents affect data on the electronictransitions in temperature 200C. Schiff base λmax / nm ( / m2. mol-1 ) Cyclohexane Carbon tetrachloride Chloroform SB1 389 * 257 ( 1410 ± 30) sh. 298 (830 ± 20) 390 (2230 ± 50 ) sh. 251 * sh. 301 391 SB2 377 * 255 (1730 ± 40) sh. 289 (610 ± 20) 378 (3380 ± 60) sh. 255 (1640 ±30) sh. 290 (820 ± 20) 380 (2390 ± 50) SB3 sh. 196 ( 630 ± 30) 206(680 ± 30) 235 (840 ± 40) sh. 251(740 ± 30) 309(660 ± 20) sh. 321(630 ± 10) 407(1040 ± 50) 246 (160 ± 5) 263 (130 ± 5) 312 (190 ± 10) 408 (400 ± 10) sh. 257(440 ± 10) 313 (540 ± 20) 409 (1790 ± 50) SB4 390 * 257( 1400 ± 40 ) sh.328 ( 1310 ± 30 ) 391( 2810 ± 60 ) sh. 253 * sh. 329 392 λmax: Wavelength of absorption maximum. *: Filtrate of saturated solution or not quantity dissolved. Chemistry | 211 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 Table (7): Variation of red shift (∆ῡ) with dielectric constant of the solvent (ε*) for highest wavelength absorption band in different solvent at temperature 20ºC. SB4 SB3 SB2 SB1 *ε Solvent ∆ῡCT ῡCT λCT ∆ῡCT ῡCT λCT ∆ῡCT ῡCT λCT CTῡ∆ CTῡ CTλ 000 25640 390 000 24570 407 000 26530 377 000 25710 389 2.023 CycloC6H12 60 25580 391 60 24510 408 70 26460 378 70 25640 390 2.238 4CCl 130 25510 392 120 24450 409 210 26320 380 130 25580 391 4.720 3CHCl 1010 24630 406 240 24330 411 560 25970 385 390 25320 395 24.33 OH5H2C 1130 24510 408 360 24210 413 620 25910 386 1010 24700 405 36.71 NCHO2)3(CH 1430 24210 413 590 23980 417 820 25710 389 1900 23810 420 78.54 O2H Table (6): The polar solvents affect data on the electronic transitions in temperature 200C. Schiff base λmax / nm ( / m2. mol – 1 ) Ethanol DMF Water SB1 198( 3620 ± 90) sh. 207(3250±70) sh.244(1750±60) sh. 298 (910±30) 395 (2150±40) 190 (4470± 80) sh.240(2480±50) 320(1480 ± 40) 405 (2420 ±60) 221(880±30) sh.257(760±20) 329(750±20) 420(880±30) SB2 197(338 ±100) sh.217 (2480±50) sh.244 (1890±70) sh. 291(920±40) 385 (2830±80) 196(9600±100) sh.219(5050±80) sh.244(4050 ±60) 296(227 ±20) 386(5050 ±70) sh.195(2290±60) 220(1630±20) sh.246(153±50) sh.299(780±40) 389(1930±50) SB3 201 (430 ± 30) sh.241(120 ± 10) 314 (120 ± 5) 411 (220 ± 10) 193(1280±40) 219(1800±60) sh.244(440±20) sh.307(500±20) b 333 (550 ±20) 413 (340 ±10) 195 a sh.217 251 sh. 309 334 417 SB4 200 (3020 ± 110) sh.222(2360±90) sh. 242(1790±60) sh.330(1360±20) 406 (2490 ± 30) 196 (4970±90) sh.225(3000±50 b 257(2240±40) sh.333(2110±40) 408(3540±70) 195(1560±60) 225(1410±30) 261(1260±20) sh.341(1420±30) 413 (1650±50) a: Not quantity dissolved. b:not clear-cut shoulder nearly. Chemistry | 212 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 Figure (1): FT-IR spectrum of Schiff base SB1. Figure (2): FT-IR spectrum of Schiff base SB2. Figure (3): FT-IR spectrum of Schiff base SB3. Figure (4): FT-IR spectrum of Schiff base SB4.               Figure (5): Electronic spectrum of SB1 in ethanol [(1) 1.998x10-5, (2) 3.996x10-5,(3) 5.994x10-5, (4) 7.992x10-5 mol. dm-3]. 190 262 334 406 478 550 Wavelength / nm 0.0 0.5 1.0 1.5 2.0 2.5 A b so rb an ce (2) (3) (4) (1) SB1 Figure (6): Electronic spectrum of SB2 in ethanol [(1) 1.584x10-5, (2) 3.168x10-5, (3) 4.752x10-5, (4) 6.336x10-5 mol. dm-3]. 190 262 334 406 478 550 Wavelength / nm 0.00 0.46 0.92 1.38 1.84 2.30 A b so rb an ce (2) (3) (4) (1) SB2 Chemistry | 213 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016             Figure (7): Electronic spectrum of SB3 in ethanol .[(1) 2.256x10-4, (2) 3.384x10-4, (3) 3.572x10-4, (4) 3.760x10-4 mol. dm-3]. 190 262 334 406 478 550 Wavelength / nm 0.00 0.38 0.76 1.14 1.52 1.90 A b so rb an ce (1) (2) (3) (4) SB3 Figure (9): The relationship between dielectric constant and red shifts for SB1. 0 16 32 48 64 80 Dielectric constant 0 380 760 1140 1520 1900 R ed s h if t / cm -1 1 2 3 5 1 Carbon tetrachloride 2 Chloroform 3 Ethanol 4 DMF 5 Water SB1 4 Figure (10): The relationship between dielectric constant and red shift for SB2. 0 16 32 48 64 80 Dielectric constant 0 164 328 492 656 820 R ed s h if t / cm -1 1 2 3 4 5 1 Carbon tetrachloride 2 Chloroform 3 Ethanol 4 DMF 5 Water SB2 Figure (11): The relationship between dielectric constant and red shift for SB3. 0 16 32 48 64 80 Dielectric constant 0 118 236 354 472 590 R ed s h if t / cm -1 1 2 3 4 5 1 Carbon tetrachloride 2 Chloroform 3 Ethanol 4 DMF 5 Water SB3 Figure (12): The relationship between dielectric constant and red shiftfor SB4. 0 16 32 48 64 80 Dielectric constant 0 286 572 858 1144 1430 R ed s h if t / cm -1 1 2 3 4 5 1 Carbon tetrachloride 2 Chloroform 3 Ethanol 4 DMF 5 Water SB4 Figure (8): Electronic spectrum of SB4 d in ethanol [(1) 2.04x10-5, (2) 4.08x10-5, (3) 6.12x10-5, (4) 8.16x10-5 mol. dm-3]. 190 262 334 406 478 550 Wavelength / nm 0.00 0.44 0.88 1.32 1.76 2.20 A b so rb an ce (2) (3) (4) (1) SB4 Chemistry | 214 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 R C R1 O + H2N H N O2N NO2 Ref lux RR1C N H N O2N NO2 Schif f bases (SB1-SB4) R R1 (1) (2) HO OH R R1 HO HO (H3C)N H2N (3) (4) H H Scheme (1): Synthesis of new Schiff bases.   OH HO C N H N O2N N O O HO Diraction of intra - CT h OH HO C N N H O2N N O O HO C H N H N O2N N Diraction of intra - CT (H3C)2 N O O H C N N H O2N N O O (H3C)2 N h Molecular chromophore (CTC) which absorbs the light at 298, 395nm Intra-CT in SB2 obtains in a similar to intra-aCT of SB1 Intra-CT in SB4obtains in a similar to intra-aCT of SB3 Molecular chromophore (CTC) which absorbs the light at 291, 385nm Scheme (2): Intramolecular charge-transfer in the synthesized aromatic Schiff bases.     OH HO C N N H O2N N O O HO H C N N H O2N N O O H2N H C N N O2N N O O (H3C)2 N HO C N N H O2N N O O OH HO C N N H O2N N O O HO (or / and)    CT = 1.134 x 10 -24 cm. molecule-1 CT = 7.570 Debye ER = 0.897 eV   CT x 10 -24cm. molecule-1 CT =7.851 Debye ER = 0.921 eV   C0.130 x  cm.molecule-1 CT = 2.614 Debye ER = 0.863 eV  V C 1.241 x 10 -2 cm. molecule-1 C= 8.029 Debye ER = 0.873 eV Scheme (3): Molecular structures of intramolecular CT complexes of SB1to SB4 which be responsible for light absorption and values of physical parameters. Chemistry | 215 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016   OH HO C N N H O2N N O O HO H C N N H O2N N O O H2N H C N N O2N N O O (H3C)2 N SB1 389 Cyclo C6H12 390 CCl4 391 CHCl3 395 C2H5OH 405 DMF 420 H2O CT/ nm Solvent 377 Cyclo C6H12 378 CCl4 380 CHCl3 385 C2H5OH 386 DMF 389 H2O OH HO C N N H O2N N O O SB2 CT/ nm Solvent 407 Cyclo C6H12 408 CCl4 409 CHCl3 411 C2H5OH 413 DMF 417 H2O CT/ nm Solvent 390 Cyclo C6H12 391 CCl4 392 CHCl3 406 C2H5OH 408 DMF 413 H2O SB3 SB4 Scheme (4): Excited molecular shapes of intramolecular CT complexes and λmaxin different solvents. Chemistry | 216 2016) عام 2العدد ( 29مجلة إبن الهيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 29 (2) 2016 تحضير وتشخيص طيفي لبعض قواعد شف االروماتية الجديدة ثنائي نيتروفنيل هيدرازين-,24المشتقة من أنور ذيب محمود الذيب نور علي خضير جامعة بغداد /كليه العلوم /قسم الكيمياء 2016:/كانون الثاني/31في،قبل 2015 كانون األول//29استلم في: الخالصه -2حضرت اربع قواعد شف اروماتية جديدة ال تتحلل مائيا بالظروف االعتيادية في هذه الدراسة بتفاعالتالتكاثف بين هيدروكسي -4وثانيامع SB1ثالثي هيدروكسي بنزوفينون ليعطي -4′4,2,ثنائي نيتروفينل هيدرازين:اوال مع,4 . SB4امينوبنزالدهايد ليعطي -4ورابعا مع SB3ثنائي مثيل امينوبنزالديهايد ليعطي -4ثالثا مع , وSB2بنزوفينون ليعطي ۥخصت التراكيب الجزيئية لقواعد شف االروماتية هذه على اساس تعيين درجات انصهارها وتحليل العناصر الدقيق شلقد المرئية. ان االنتقاالت االلكترونيه التي تم الحصول عليها درست في -ت الحمراء وفوق البنفسجيةوتسجيل اطيافها تح مذيبات االيثانول وثنائي مثيل فورمايد والماي والكلورفورم ورابع كلوريد الكاربون والهكسان الحلقي, وتعود حزم لمناظره.تعود حزم االمتصاص التي تم الحصول عليها االمتصاص المسجلة في مذيب االيثانول الى انتقالتها االلكترونيه ا )نانومترا في االطياف االلكترونية لقواعد شف االروماتية الجديدة المحضرة الى االنتقاالت 411الى 291عند → ∗) نتقاالت بانها ت هذه االَّالناشئة من حلقات البنزوفينون وااللديهايد المعوضة والممتدة على طول الجزيئة في قواعد شف. عد الشحنة الضمني إذ حيث تلعب اجزاء حلقات البنزوفينون والبنزالديهايد المعوضه كواهبات للشحنة - حزم معقدات انتقال وحلقه الفينيل هيدرازين المعوضه كمستقبل للشحنة. وايضا تم قياس ومناقشة تأثير المذيبات القطبية وغير القطبية في الشحنة.- مه معقد انتقالاالنتقاالت االلكترونية لحز الشحنة الضمني مثل - حسبت ونوقشت المعامالت الطيفية والفيزياوية للهيئات التركيبة الجزيئية لجزيئات معقدات انتقال طاقات االنتقال ومعامل االمتصاص الموالري وشدة التذبذب الجزيئي وعزم ثنائي القطب الجزيئي االنتقالي وطاقه الرنين الجزيئي. معقدات شف، معقدات انتقال الشحنة، طيف االشعة تحت الحمراء، األشعة المرئية فوق قواعد شف، :المفتاحية الكلمات البنفسجية، تحليل العناصر الدقيقة