The Preparation, Characterization and the Study of the Linear Optical Properties of a New Azo Compound

Transcription

1 Journal of Basrah Researches ((Sciences)) Volume 37.Number 15 April ((011)) The Preparation, Characterization an the Stuy of the Linear Optical Properties of a New Azo Compoun 1 Hasanain A S. A Majee, Alaa Yassin Al-Ahma an 1 Kawkab Ali Hussain 1 Department of Chemistry Department of Physics College of Eucation Basrah University. Basrah Iraq ISSN (Receive 19 January 011; Accepte 8 March 011) Abstract Azo ye was prepare from 4,4-iaminoiphenyl sulfone with chromotrpic aci by fox metho. Azo ye was ientifie via IR-Infrare spectrophotometer, UV-visible spectroscopy an elemental analysis (CHN). The basic optical properties of azo ye have been stuie at room temperature. The optical energy gap was estimate from the absorption coefficient values using Taue s proceure. The values of the static refractive inex ( n ), the static ielectric constant ( ), oscillator energy ( E o), ispersion energy ( E ), the moments of optical ispersion spectra, an the ban gap energy ( E g ) have been etermine by the Wimple-Diomenico metho. Key wors: Azo ye, Ban gap energy, Refraction inex, Oscillator parameters. Introuction The iscovery of iazo compouns occurre aroun the year 1858, which parallels heterocycles or enolizable aliphatic groups [4]. Azo yes can be classifie either accoring to the beginning of what is consiere the starting chemical guieline (characteristic chemical point of moern organic chemistry[1]. Azo yes contain one or more azo groups ( - N =N - ) groups) or by color aspects (application in ye works) [5]. Azo yes are the most important which are linke to SP hybriize carbon class of inustrial yes, both in number an atoms, base on the number of such groups []. amount, in yeing wool, semiconuctivity The synthesis of most azo yes involves the textile an foo inustries [6-9] iazotization of a primary aromatic amine, In the present stuy azo compoun were followe by coupling with one or more prepare an Ientifie by IR, UV Visible nucleophilic aromatic compoun such as an aryl spectroscopy an elemental analysis (CHN). amine or a phenol [3]. The azo groups are The optical constants of the sample are generally connecte to benzene an naphthalene etermine by optical characterization metho. rings, but can also be attache to aromatic corresponing author. aress: alaa_ta005@yahoo.com 64

2 The Preparation, Characterization an the Stuy of the Linear Optical Properties of a New Methanol, chromotropic aci isoium salt ehyrate, soium hyroxie from ( Fluka Co.), 4,4-iaminoiphenyl sulfone, soium nitrite, hyrochloric aci from (Merck Co.), were purifie before using [10]. Physical measurements, IR spectra were recore on a Buck Scientific Moel 500. IR spectrophotometer using a KBr isc in the range ( ) cm -1. Absorption Spectra in Methanol were etermine on a U Experimental Reagent HITACH UV-visible spectrophotometer in the range ( nm). The melting point (MP) of the compouns was etermine with a 9300 Moel Electro thermal melting point. IR, UVvisible spectrophotometer an melting point was performe by Chemistry Department Eucation College Basrah University. Elemental analysis ( CHN ) of the compouns was etermine with (Euro Vector EA 3000A Italy) was performe by AL-al-bayt university. Methos Synthesis of the Azo Dyes The above azo yes were prepare by a metho similar to that escribe by Fox [11]. In the present metho the yes were prepare as the follows: 1. (0.006mole, g) of amine was issolve in ml of conc. HCl an then 10ml of istille water was ae, the mixture was stirre an kept in ice bath g of NaNO was issolve in about 5ml of istille water an kept in ice bath. 3. Diazonium salt was prepare by aing soium nitrite solution in step () ropwise to the col solution of amine in the step (1) with stirring an kept the temperature below 50 o C. 4. Coupler was prepare by issolving (0.006mole,.4017g) of chromotropic aci isoium salt ehyrate in 5% soium hyroxie solution an keeping in ice bath. 5. The iazonium salt was ae ropwisely to the couplers with constant stirring, keeping the temperature below 50 o C; the yes were neutralize with ilute hyrochloric aci solution. 6. The resulting crues were recrystallize from methanol the purity of the resulting azo ye, 94% yiel, M.P. >300 o C, orange color. Azo ye has been characterize by elemental analysis, IR, an UV spectra. The structure of the azo ye is shown in figure 1. SO3H O O N N S NH OH NH Figure 1. chemical structures of the prepare azo ye compoun 65

3 A Majee, Al-Ahma & Hussain In this paper, we escribe the synthesis of azo ye from 4,4-iaminoiphenyl sulfone with chromotrpic aci, were forme in goo yiel, an it s stable at room temperature an are nonhygroscopic. The structures of the compositions of the prepare azo ye were etermine by elemental analysis for C, H an N. The obtaine results are shown in Table 1. A reasonable agreement between the foun an calculate ata was foun. The azo ye was ientifie by IR spectroscopy in the range ( ) cm -1 as KBr iscs is shown in Figure 4. The stretching vibration of the OH groups which appeare in the region ( ) cm -1. The ban shows broa appearance ue to its Result an Discussion relatively low frequency. It can be conclue that the OH groups may form a hyrogen bon with nitrogen atom. Also azo ye shows two absorption bans ( ) cm -1 which may be attribute to the ( -NH) group, which overlaps with the stretching vibration of the OH groups. The ban corresponing to N=N stretching vibration usually lies aroun 1500 cm - 1 [1], the C=C stretching vibration of the aromatic ring shows a strong ban in the region (1590) cm -1, stretching vibration of the (C-H) aromatic appear at (900) cm -1 [13-14]. The all mentione bans were shown in table1. Figure. IR-spectrum of azo ye 73

4 The Preparation, Characterization an the Stuy of the Linear Optical Properties of a New Table 1. IR an C.H.N ata for azo ye compoun (Br:broa, s:sharp, m:meium, w:weak) Wave numbers ( cm -1 ) Calculate (Foun)(%) Compoun O-H C=C N-H N=N C-H C H N m m br s m Azo ye I (53.00) (3.63) (11.3) Azo ye has receive great attention ue to its environmental stability, ease of preparation, an its optical an electrical properties. Optical properties of any azo ye are important for optical applications, because optical properties are irectly relate to their structural an electronic properties [15]. Linear optical properties have been the subject of numerous investigation by both theoreticians an experimentalists in recent years ue to the potential applications in optical signal processing an computing [16]. Detaile The azo ye film use in the present stuy was prepare as follows: (0.5gm) of azo ye power was issolve in (10 ml )ethanol, the ye solution was stirre at room temperature for 45min, then the solution is filtere through (0.m)syringe filter. The film was prepare by the repeat- spray metho on a clean glass slie substrate of (5 mm 5 mm 1 mm) in size that is heate up to 70 o C. Smooth film without ust an solvent resiues was obtaine. The thickness of the film is about (30 m), an the film samples have goo purity an uniform thickenss. Linear Optical Properties: Sample Preparation an Optical Measurements investigation of linear optical coefficients is ables to fabricate materials, appropriately esigne at the molecular level for specific applications such as optoelectronic evices. Knowlege of optical constant of the materials (optical ban gap an extinction coefficient) is vital to scrutinize the atomic structure, electronic ban structure an electrical properties. The refractive inex provies the information about the chemical boning an electronic structure of the material [17]. UV-visible spectroscopy has been use to characterize the sample in the spectral range ( nm) in steps of nm. The transmittance (T) an the absorbance (A) of azo ye measurements using ouble beam UV- Visible spectrophotometer (U HITACH). These measurements were performe at room temperature. Fig.(1) shows the spectral istribution of absorbance for azo ye film in the spectral range ( nm), figure 3 shows that the peak of absorption is locate at 305 nm. 67

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6 A Majee, Al-Ahma & Hussain Figure 3. Absorption spectra of azo ye film The analysis of optical transmission spectra is one of the most prouctive tools for unerstaning an eveloping the ban structure an energy ban gap of materials. The spectral epenence on transmittance (T) an reflectance (R) for azo ye is given in figure 4. The reflectance was calculate using the following equation [18] Where is the cell path length an ( ) is the absorption coefficient. From the transmittance an the reflectance spectral of azo ye we can see that at a large wavelength ( >800 nm) the azo ye shows high transmission. The in quality(r+t<1) at wavelength ( < 800 nm) implies the existence of absorption, i.e. an absorbing region. T (1 R) exp( ) (1) 73

7 The Preparation, Characterization an the Stuy of the Linear Optical Properties of a New Figure4. The spectral istribution of transmittance (T) an reflectance (R) as a function of wavelength for azo ye film. The refraction inex (n) an extinction coefficient (k) provies the optical properties of the azo ye an the are relate by [19]. 1 R 4R n ( ) ( k ) () 1 R (1 R) The absorption coefficient ( ) can be calculate from the transmittance spectral ata using Beer Lamber s formula (.303( A / )), where A is the optical absorbance of the ye. The extinction coefficient (k) can be obtaine from the relation ( k / 4 ), where is the wavelength of the light. Figure 5 an 6 show the variation of the refraction inex an extinction coefficient as a function of wavelength. From the figures we can see that the values of refractive inex (n) an extinction coefficient (k) in the region of ( nm) are sharply ecreases with increasing of the wavelength. In the region ( nm) the values of n an k ecreases graually. This is ue to high energy transition. 69

8 A Majee, Al-Ahma & Hussain Figure 5. Refraction inex as a function of wavelength for azo ye film. Figure 6. Extinction coefficient as a function of wavelength for azo ye film. 73

9 The Preparation, Characterization an the Stuy of the Linear Optical Properties of a New By employing the Wemple-DiDomenico single oscillator moel [0] in the region of normal ispersion ( > 300nm), we analyz the measure refractive inices an the ata are then use to obtain the oscillator parameters. Equations (3) escribes the relationship between the refractive inices an the oscillator parameters. 1 E ( n 1) E E E E Where (E =h ) is the photon energy, h is the Planck constant, is the photon frequency, E ) is the average excitation energy for ( o (3) electronic transitions an ( E ) is the ispersion energy which is a measure of the average strength of inter-ban optical transitions or the oscillator strength. Figure 7 shows the plotting 1 of ( n 1) against ( h ) which allows us to etermine the oscillator strength parameters by fitting a linear function to the lower energy ata. The point of interception with the orinate at ( E( h ) 0) yiels the value of ielectric constant at higher wavelength ( ). The values of ( Eo ) an ( E ) are obtaine from the intercept an the slope of the curve an the static refractive inex ( n ) is calculate using this E relation n ( h 0) 1. E Figure 7. Variation of ( n 1) versus (hv) for azo ye film. The moments of optical ispersion spectra M -1 an M -3, can be evaluate using the relations [0]. 1 E (4) 3 M M 3 M 1 E (5) M 3 The variation in the absorption coefficient () is relate to the photon energy h for the interban transition by the relation [1] 71

10 A Majee, Al-Ahma & Hussain opt r h B ( h E g ) (6) Where (r=1/) an () in the case of irect an inirect optical transition respectively, h is the photon energy, B is the opt ban tail parameter an ( E ) is the optical ban gap. Figure 8 shows the irect allowe g transition (r=1/). Extrapolating the linear part towars lower photon energies, the point of interception with h axis at (( h ) 0) giving the corresponing irect energy ban gap ( E ). g Figure 8. Depenence of ( h) on the photon energy. The values of the static refractive inex n ), the static ielectric constant ), ( ( oscillator energy ( E o ), ispersion energy ( E ), the moments of optical ispersion spectra M -1 an M -3, an irect energy ban gap ( E ) are liste in table. g n E (ev ) (ev ) Table. Optical constant of azo ye film. E E E (ev ) M 1 (ev) 3 (ev) M ( ) E g E E g

11 A Majee, Al-Ahma & Hussain Azo ye compouns has been synthesize from from 4,4-iaminoiphenyl sulfone with chromotrpic aci. The azo yes were investigate by infrare spectra an C.H.N analysis. Optical transmission an absorption spectrum is use to calculate the optical Conclusions absorption coefficient, refractive inex, extinction coefficient, optical ban gap an oscillator parameters. The UV-visible spectroscopic stuies shows that the new Azo compoun has high refractive inex an high value of static ielectric constant. References [1]T. Manel., an Y. Inber., Chem. Phys. Lett. 165, 387(004). []W. Catelen., an G. Koller., J. Phys. Chem. 198, 879(006). [3]A. Cheo., an J. Marteze., J. Phys. Chem. 65, 31(006). [4 ] Q. Zheange., an H. Chin., J.Am. Chem.Soc. 143, (003) [5] X. Wang., an S. Hungir., V. Frish., Chem. Mater. 14, (007) [6]R. Bruenti., an A. Millan., In. J. Chem, 64A, 63, (008). [7]F. Ciolksce., an Q. Rabuk., J.Chem.Phys.76, 885 (006) [8] B. Ayle., an Y. Danels., Molecules Reviews, 13, , (007) [9] A. Tawer., an T. Zhenat., Molecules, 13, (005). [10 ] W. L. F. Armarego an D. D. Perrin, Purification of Laboratory Chemicals 101,08(1998) [11] J. J, Fox., J. Chem. Soc, 97, 1339, (1910). [ 1] K. Nakanish an P.Solomon." Infrare Absorption Spectroscopy ". HOLDEN- DAY, Inc Lonon, Syeny.(1977). [13] W. J.Crrile an G.P.Eilis, "Spactral an Chemical Charactreization of organic Compouns". Thir Eition Great Britauin (1994). [14 ] T. Kalabovi., an G. Xaenet, Russian J. Coor. Chem. 45, 54, (009). [15] Deshmukh, D K Burghate, S N Shilaskar, G N Chauhari an P T Deshmukh, Inian J. of Pure & Appl. Phys. V46, pp (008). [16 ] P. V. Mehta, N. Tripathi, an S. K. Kumar, Chalcogenie Lett., 39 (005). [17 ] Yin M. Li HP. Tang SH. Ji W.,Appl. Phys. B (000). [18 ] J. I. Pankove, Optical Processes in semiconuctors, Dover Publication Institute, New York, [19] M. R. Islam an J. Poer, Cryst. Res. Technol. 44,86 (009). [0] S. H. Wemple an M. Diomenico,Jr., J. Phys. Rev. B Vol. 3 p (1971). [1] E. A. Davis an N. F. Mott, Philos. Mag., 903 (1970). :