P 3 spektrometri proton nmr

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Slide ini membahas mengenai : pengertian, kegunaan, prinsip dasar, bentuk spektrum, dan Interpretasi spektrum proton NMR.

Transcript of P 3 spektrometri proton nmr

  • 1. SPEKTROMETRI PROTON NMROLEH :YUSBARINA, M.SiJURUSAN P. KIMIA FTK UIN SUSKA RIAU

2. NMR ?NUCLEAR MAGNETIC RESONANCEATAURESONANSI MAGNET INTIH-NMR C-NMR 3. Kegunaan H-NMR?Memberikan gambaran mengenai :1. Jenis hidrogen2. Jumlah hidrogen3. Lingkungan hidrogen dalamsuatu senyawa 4. Prinsip dasar H-NMR?NMR didasarkan pada penyerapangelombang radio oleh inti intitertentu dalam molekul organik,apabila molekul tersebut berada dalammedan magnet yang kuat 5. Fenomena Resonansi Magnetik IntiModel fisika klasik:Inti atom bermuatan positif dan berputar pada porosnya(spin) membentuk medan magnet yang berputar penempatan di dalam suatu medan magnet (Bo)menghasilkan putaran presesi yang menyerap di daerahgelombang radio frekuensi presesi dinyatakan oleh: 6. Proses terjadinya resonansi? 7. When molecules containing hydrogen atoms areplaced in an external magnetic field ; themagnetic moment of each proton nucleusaligns itself in one of two differentorientations: 8. The parallel protons absorb energy (radiowaves) and the magnetic moment turnaround (flip) to the high energy antiparallelstate (Resonance) 9. 2 Cara agar terjadi resonansi?Bo tetap,frekuensi radiasielektromagnetikdiubah - ubahfrekuensi radiasielektromagnetiktetap, Bo diubah ubah sampaidicapai resonansi,Lebih memuaskan 10. Bentuk spektrum NMR? 11. The spectrum is measured on a delta ( ) scale in unitsof parts per million (ppm)Lower frequency is to the left in the spectrum; theseabsorptions are said to be downfieldHigher frequency is to the right in the spectrum:these absorptions are said to be upfieldThe small signal at 0 corresponds to an internalstandard called tetramethylsilane (TMS) used tocalibrate the chemical shift scaleThe number of signals in the spectrum correspondsto the number of unique sets of protons 12. Pergesaran Kimia?Perbandingan antara letak resonansisuatu proton tertentu dengan letakresonansi proton standar 13. Chemical Shift Chemical shifts are measured in relation to theinternal reference tetramethylsilane (TMS) The protons of TMS are highly shielded because of thestrong electron donating capability of silicon The scale for chemical shifts is independent ofthe magnetic field strength of the instrument(whereas the absolute frequency depends on fieldstrength) 14. Ada apa denganTMS?1. TMS mempunyai dua belas proton yang setarakimia,karenya memberikan satu puncak tunggal2. TMS merupakan cairan yang volatil, dapat ditambahkandalam jumlah sedikit pada larutan sampel dalampelarutnya, sampel dapat diperoleh kembali denganmenguapkan pelarutnya3. Proton pada hampir semua senyawa organik mengalamiresonansi pada medan yang lebih rendah daripada protonTMS4. TMS bersifat inert dan tidak larut dalam air 15. Faktor yang mempengaruhipergesaran kimia? 16. Faktor intramolekular1. Efek induksi2. Efek anisotropi3. Efek mesomeriFaktor intermolekuler1. Ikatan hidrogen2. Temperatur3. Pelarut 17. Fields induced by sigma bonds The induced field from circulating sigma bondelectrons opposes Ho in the vicinity of proton 18. A proton that is bonded to the same carbon as anelectronegative atom is more deshielded than protonon other carbons. (Inductive Effect) H3C-F H3C-ClH3C-Br H3C-IIncreased shielding of HC FHHHF causes a decrease ine density around each atom 19. The inductive effectCHHHCHHCHHX effect of X is importantin decreasing e densityaround this protoneffect of X is oflittle importancein decreasinge density aroundthis protonSiCH3CH3CH3CH3greater e density on H:highly shieldedTetramethylsilane(TMS) 20. Summary of induced field effects 21. Equivalent and nonequivalent protonsMENGHITUNG PROTON 22. CH3CH2OCH2CH3six equivalent protonsfour equivalent protons 23. CCH3CH3HBr six equivalent protonsCH3CH3CH3 Br six equivalent protonstwo 24. Spin-spin coupling Protons that split each other signals are saidto have undergone spin-spin coupling 25. n+1 Rule The number of peaks of a particular proton isequal to number (n) of nonequivalent protonson the adjacent atoms + 1 26. Notice: 27. Splitting pattern: The singletIf no neighboring nonequivalent protons present one single peak (singlet) (S).eg.CH3 Cl CH3OCCH3OCCH3CH3BrCH3 HHHHHH 28. The doublet If one neighboring nonequivalent proton present two peaks (doublet) (d).egCH3 CHClCl CH3 CHClCH3OCH3HHCH3H HC CHHClCl ClClequivalent Hs => S 29. The triplet If two neighboring nonequivalent protons present three peaks (triplet) (t).egCH3CH2ClC CHHClCl ClHClCH2CH2OCH3 30. The quartet If a proton is neighboring to CH3 it will observe3+1=4 peaks (quartet) (q)egCH3CH2Cl CH3CHCl2CH3CH2OCH2CH3