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Presentation on theme: "Down load แผ่นใส Power point ประกาศต่างๆที่ www.weerachai.tk Down load ได้ที่ www.weerachai.tk."— Presentation transcript:

1 Down load แผ่นใส Power point ประกาศต่างๆที่ Down load ได้ที่

2 Off Resonance Decoupling ทำให้ทราบว่า C แต่ละตัว จับกับ H กี่ตัว ตามกฏ n+1 rule Down load ได้ที่

3 A Quick Dip Into DEPT Distortionless Enhancement by Polarization Transfer -Mordern method of off-resonance -Requires an FT-pulsed spectrometer -CH (+) –CH or –CH3 (-) –CH2 protonated C Down load ได้ที่

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6 Compounds with Aromatic Rings Down load ได้ที่

7 Introduction to 2D NMR spectroscopy COSY The basic 2D NMR experiment based on through-bond scalar coupling is COSY(COrrelated SpectroscopY). The COSY experiment has the simplest pulse sequence of all 2D NMR experiments. The pulse sequence is shown in Figure Figure 1.1: The pulse sequence of the 2D correlated spectroscopy (COSY). Two 90-degree pulses are separated by the mixing period. In this experiment the spins undergo precession about one another, in addition to the usual precession about the applied magnetic field. During the mixing period, i.e., the second pulse, of this experiment, J-coupled spins exchange coherence and communicate the information about their precession frequencies. The result, for the COSY experiment, is that a cross peak between two spins, i, and j, will occur in the spectrum if spin i and j are directly coupled to one another. The cross peaks in COSY spectra are antiphase in character, that is, half of the multiplet is "up" and the other half is "down" as shown in a simulated 2D COSY spectrum in Figure Figure 1.2: Simulated 2D COSY contour plot of two coupling spins. Open circles with solid and dashed lines are cross peaks with positive and negative intensity, respectively. The dispersive diagonal peaks are represented by filled circles. This feature increases the difficulties of doing automated peak picking. To determine the center of each cross peak, two local maxima and minima have to be found which is difficult in a severely overlapped spectrum. Down load ได้ที่

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9 2-nitropropane Down load ได้ที่

10 Isopentyl acetate Down load ได้ที่

11 Isopentyl acetate Down load ได้ที่

12 citronellol Down load ได้ที่

13 HETCOR(HETeronuclear chemical shift CORrelation) HMQC (Heteronuclear Multiple Quantum Correlation) and HSQC (Heteronuclear Single Quantum Correlation) experiments correlate the chemical shift of proton with the chemical shift of the directly bonded carbon (or nitrogen). This experiment utilizes one-bond couplings 2-nitropropane Down load ได้ที่

14 Isopentyl acetate Down load ได้ที่

15 4-methyl-2-pentanol Down load ได้ที่


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