1. Mustafa KUMRU Fatih University, Faculty of Arts and Sciences, Physics Department, 34500 Büyükçekmece, Istanbul

2. CONTENTS 1. INTRODUCTION 2. EXPERIMENTAL 3.1 Material 3.2 FT-IR Spectroscopy of Molecules 3.2.1 FT-FIR Spectroscopy of Molecules 3.3 FT-Raman Spectroscopy of molecules 3.4 Dispersive Raman spectroscopy of molecules 3. RESULTS 4.1 Vibrational Spectra of 2QC 4.2 Vibrational Spectra of 3QC 4.3 Vibrational Spectra of 4QC 4. CONCLUSIONS

3. Quinoline is an aromatic nitrogen compound characterized by a double –ring structure contains a benzene fused to pyridine at two adjacent carbon atoms. Quinoline and its derivatives have been the research area of many scientists due to their presence in the areas : Biological medicine Chemicals many other industrial processes 2-Quinolinecarboxaldehyde 3-Quinolinecarboxaldehyde4-Quinolinecarboxaldehyde INTRODUCTION Structures and vibrational spectra of these molecules were investigated.

4. Materials 2QC and 4QC with 97% purity were purchased from Alfa Aesar, U.S.A., 3QC with 98% purity was purchased from Alfa Aesar, Germany. These molecules have been used without any further purification. EXPERIMENTAL

5. IR Measurements Mid IR spectra were recorded with ATR. The room temperature far FT-IR (FT-FIR) spectra of 2,3,4-quinolinecarboxaldehyde (600-50 cm -1 ) were recorded by preparing Polyethylene Pellets (PE) by using Nicolet 6700 FT-IR spectrometer. The PE and the sample are mixed and ground in a mortar. The metallic anvil die accessory used for making the pellets, is also used in this case. Unlike pellets, the die is heated to 250 °C on a heater until its red light turns off. The temperature is expected to be approximately 130–150 °C (the melting temperature of PE is 120–130 °C). The mixture of PE and the sample are quickly added in the die, which is assembled and put under 5-ton pressure for 2 min. The die is disassembled and the resulting PE pellet is put in the sample pellet holder into the IR spectrometer and FIR spectrum is recorded in the 650–50 cm -1 region.

6. FT-Raman Measurements The FT- Raman spectra were recorded with NXR 9650 FT-Raman Spectrometer in the range of 4000-50 cm -1 at the room temperature. The laser have been used has the wavelength of 1024 nm and The InGaAs detector have been used. Dispersive Raman Measurements The Dispersive Raman spectra of 2QC, 3QC and 4QC were recorded with Dispersive Raman Microscope (DXR) in the range 3500-50 cm -1 at the room temperature. The laser used has the wavelength of 780 nm.

7. EVALUATION OF THE RESULTS

8. Vibrational Spectra of 2QC : FT-IR spectrum of 2QC

9. FT-FIR spectrum of 2QC

10. FT-Raman spectrum of 2QC

11. Dispersive Raman spectrum of 2QC

12. The ring C-H stretching vibrations of 2QC are observed at 3058, 3054, 3034, 3019, 3016, 3000 cm -1. The C-H in plane bending vibrations of 2QC are found at 1299, 1264, 1231, 1203, 1149, 1114 cm -1. The C-H out of plane bending vibrations are found at 998, 990, 986, 838, 762, 752 cm -1. All C-H vibrations are in good agreement with the literature. The ring C-C stretching vibrations give rise to bands in the region 1637- 1503 cm -1. The in plane and out of plane C-C-C deformation bands occur in the region at 752-523 cm -1. The ring C-CHO stretching vibration occurs at 1231 cm -1.

13. The ring C-N stretching vibrations observed at 1336 cm -1 (IR) and 1358 cm - 1 (Dispersive Raman) are from the ring C-N stretching. The C=N ring stretching vibration were observed at 1503 cm -1 (IR). The C=O stretching vibration of 2QC is observed at 1703 cm-1 in FT-IR, 1709 cm -1 in FT-Raman and 1704 cm -1 in Dispersive Raman. However, The C-O in plane bending vibration is observed at 748 cm -1 in FT-IR, 746 cm -1 in Dispersive Raman. The C-O out of plane bending vibration is at 282 cm -1.

14. Vibrational Spectra of 3QC : FT-IR spectrum of 3QC

15. FT-FIR spectrum of 3QC

16. FT-Raman spectrum of 3QC

17. Dispersive Raman spectrum of 3QC

18. The C-H stretching vibrations are observed at 3070, 3066, 3043, 3029, 3006, 3000 cm -1. However, one C-H stretching vibration of the aldehyde groups is observed at 2689 cm -1. The C-H in plane bending vibrations of 3QC have been found at 1266, 1211, 1162, 1141, 1122 cm -1. The C-H out of plane bending vibrations are found at 993, 983, 907, 876, 786 cm -1. The C-C stretching vibration frequencies are observed in the region 1601- 1422 cm -1. The C-C-C deformation bands occur in the region 751-523 cm -1. The ring C-CHO stretching vibration are observed at 1162 cm -1 (FT-IR) and 1167 cm -1 (Raman).

19. The ring C-N vibration frequency was observed at 1335 cm -1 (FT-IR) are from. The C=N ring stretching vibrations were observed at 1569 cm -1 (FT-IR), 1600 cm -1 (FT-Raman) and 1567 cm -1 (Dispersive Raman). The C=O stretching vibration of 3QC was observed at 1695 cm -1 in FT-IR, 1690 cm -1 in FT-Raman and 1686 cm -1 in Dispersive Raman. The C-O in plane bending vibration is observed at 668 cm -1 in FT-IR. The C-O out of plane bending vibration is at 268 cm -1.

20. Vibrational Spectra of 4QC : FT-IR spectrum of 4QC

21. FT-FIR spectrum of 4QC

22. FT-Raman spectrum of 4QC

23. Dispersive Raman spectrum of 4QC

24. The C-H stretching vibrations which are observed at 3080, 3066, 3057, 3028, 3011, 3008 cm -1. However, one C-H stretching vibration of the aldehyde groups is observed at 2832 cm -1. The C-H in plane bending vibrations of 4QC are found at 1290, 1265, 1210, 1158, 1137, 1095 cm -1. The C-H out of plane bending vibrations are found at 961, 883, 847, 772, 748 cm -1. The ring C-C stretching vibrations occur in the region 1634-1343 cm -1. The C-C-C deformation bands occur in the region 772-547 cm -1. C-CHO stretching vibration occur at 1210 cm -1.

25. The ring C-N stretching vibration bands were observed at 1320 cm -1 (IR) and 1301 cm -1 (Raman). Furthermore, the C=N ring stretching vibrations were found at 1568 cm -1 (IR) and 1563 cm -1 (Raman). The C=O stretching vibration has been observed at 1739 cm -1 in FT-IR, 1697 cm -1 in FT-Raman. The C-O in plane bending vibration has been observed at 709 cm -1 in FT-IR, 710 cm -1 Raman and 706 cm -1 in Dispersive Raman. The C-O out of plane bending vibration was observed at 138 cm -1 in Raman.

26. Vibrational Spectra of 2QC, 3QC and 4QC in FT-IR

27. Vibrational Spectra of 2QC, 3QC and 4QC in FT-FIR

28. Vibrational Spectra of 2QC, 3QC and 4QC in FT-RA

29. Vibrational Spectra of 2QC, 3QC and 4QC in Disp. Ra

30. Experimental vibrational frequencies of 2QC, 3QC and 4QC and their mode assignments

33. Experimental and calculated scaled vibrational frequencies of 2QC

36. Experimental and calculated scaled vibrational frequencies of 3QC

39. Experimental and calculated scaled vibrational frequencies of 4QC

42. V ibrational spectra of n-quinolinecarboxaldehyde, where n = 2, 3 and 4, have been obtained experimentally by using FT-IR (including mid and far region), FT-Raman and Dispersive Raman methods. The position of carboxaldehyde (-HC=O) unit affects the vibrational spectra significantly. There is a strong broad peak in the spectrum of 4QC at 3226 cm -1 that is absent in the spectra of 2QC and 3QC. This peak arises from the H- bond between one of the benzene hydrogens and O of carboxaldehyde, i.e. H  O. CONCLUSIONS H

43. Our Related Articles: V. Küçük, A. Altun, M. Kumru, "Combined experimental and theoretical studies on the vibrational spectra of 2-quinolinecarboxaldehyde", Spectrochim Acta Part A 85(2012)92–98 M. Kumru, V. Küçük, T. Bardakçı, “Theoretical and experimental studies on the vibrational spectra of 3-quinolinecarboxaldehyde", Spectrochim Acta Part A 90(2012)28–34 M. Kumru, V. Küçük, P. Akyürek, “Vibrational spectra of Quinoline-4- carbaldehyde: Combined experimental and theoretical studies”, (Submitted to Journal)

44. Acknowledgement Fatih University research fund Assoc. Prof. Ahmet ALTUN Assoc. Prof. Kurtuluş GÖLCÜK Assoc. Prof. Levent SARI Dr. Vesile KÜÇÜK Tayyibe BARDAKÇI Perihan AKYÜREK Mustafa KOCADEMİR