Ph. D. THESIS 2009

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conformation of the enol form, stabilized by hydrogen bonds (the best agreement between spectra). For theoretical modeling of IR spectra of the enol form were considered two tautomeric structures, namely conf_A, where the Hbonds are established between the enol OH group and the oxygen belonging to the methoxy fragment, and conf-B, where the H-bonds are established between the enol OH group and the carbonyl oxygen of the ester group. Both structures are presented in Figure 5. Therefore, for the sake of clarity we will still use these names in order to denote the corresponding structures during this study. a b Figure 5. Two possible conformations of the enol form: a) conf_A; b) conf_B. In Figure 6 are presented comparatively the experimental spectrum in solution and the theoretical spectra for both conformations modeled for compound 1. Absorbance [a.u.] 100 80 60 40 20 0 1628 1663 1600 1650 1700 1750 1800 1850 Wavenumber [cm -1 ] 1739 13 Conf_A Conf_B Exp Figure 6. Theoretical and experimental IR spectra (1600 – 1800 cm-1) in the C=O and C=C stretching region, using dichloromethane as solvent. The presence of carbon-carbon double bond peak around 1630 cm -1 associated with the carbon-oxygen double bond peak around 1660 cm -1 , characteristic to the carbonyl stretching vibration in enols, comes to support the preference of compound 1 for enol form. The partial unagreement between the theoretical and experimental spectra originates from the dimension of the basis
set used , the anarmonicities that occurs and the fact that the molecule is considered as being isolated. 1.4. Solid state investigations The experimental FT-IR and FT-Raman spectra of the 1 are presented in Figure 7, in order to draw conclusions about the vibrational behaviour of compound 1. Absorbance (a.u.) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 (2) (1) 706 839 757 809 840 923 947 992 1031 FT-IR (1) FT-Raman (2) 1171 1101 1168 1195 1278 1311 1353 1438 1447 0.0 600 800 1000 1200 1400 1600 1800 Wavenumber (cm-1 ) 1241 1256 1357 1446 1630 1627 1660 1729 1740 1661 1734 1743 14 Absorbance (a.u.) 0.20 0.15 0.10 0.05 0.00 839 2844 757 2844 2871 2870 2947 2959 2938 2956 454 368 233 3003 3029 3005 3025 3050 (2) 2900 3000 3100 Wavenumber (cm -1 ) a b Figure 7. a) FT-IR (ATR) and FT-Raman spectra of the compound 1; b) The corresponding high wavenumber spectral regions. Excitation: 1064 nm, 380 mW Th e e xp er im en t a l FT-IR a n d FT-Ra m a n sp ect r a o f t h e co m p o u n d 2 a r e p r e se n t ed in Figu r e 8 , in o r d er t o est a b lish co m m o n a s well a s d iffer en t elem en t s a b o u t t h e v ib r a t io n a l b eh a vio u r o f 2 r e la t iv ely t o co m p o u n d 1 . Due to the molecular symmetry, a considerable number of frequency lines are missing both from the IR and Raman spectra (Figure 8), while the other lines have very small intensity. Both absorption spectra are simpler than in the case of structure 1. (1)
Page 1 and 2: “BABES-BOLYAI” UNIVERSITY CLUJ-
Page 3 and 4: General Introduction OUTLINE Part A
Page 5 and 6: 3.6.1. Dots 188 3.6.2. 3D structure
Page 7 and 8: Part A: Synthesis and Structural An
Page 9 and 10: H 3C H 3C O O O C C O O 1a O O C C
Page 11 and 12: The two forms are in equilibrium an
Page 13: Figu re 4 . Th e 13 C-NMR APT (CDCl
Page 17 and 18: Figure 9. ORTEP diagram for the bic
Page 19 and 20: 1.5.1. Tetramethyl 3,7-dihydroxybic
Page 21 and 22: Table 7. The selected molecular par
Page 23 and 24: a b Figure 14. 1 H NMR spectrum (CD
Page 25 and 26: Figure 16. 13 C NMR spectrum APT (C
Page 27 and 28: Absorbance (a. u.) Absorbance (a.u.
Page 29 and 30: icyclo[3.3.1]nonane-3,7-dione solut
Page 31 and 32: m u lt ip let a t a t δ ==1 .7 6 p
Page 33 and 34: Figure 22. 13 C NMR APT spectrum of
Page 35 and 36: Figure 24. NMR investigation of the
Page 37 and 38: (mol·l -1 ) syn 8.8 x10 -3 1.4373
Page 39 and 40: a b Figure 29. 3D FTIR spectra in s
Page 41 and 42: Figure 32. ORTEP diagram for the cy
Page 43 and 44: H2 … N3 = 1.839 Å H5 … N6 = 1.
Page 45 and 46: 2. Conclusions of the part A Differ
Page 47: 20. L. J. Bellamy, “Advanced in I
Page 50 and 51: 2. Experimental part: fabrication a
Page 52 and 53: 3 m 30 m a b Figure 4. Optical imag
Page 54 and 55: (NA 1.25) in phase-contrast (a) and
Page 56 and 57: was chosen instead of an aqueous on
Page 58 and 59: Our goal is to develope a lasser as
Page 60 and 61: Figure 15. a Optical image of gold
Page 62 and 63: the power as parameter exhibits a m
Page 64 and 65:
a b Figure 21 a) Optical image of g
Page 66:
4.5.3. 3D structures The 3D structu
Page 69 and 70:
Selected References 1. E. S. Wu, J.
Page 71:
VIII. J. Bosson-Ehoomann, A. Mihut,
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Ph. D. THESIS 2009

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