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# Uv vis spektra senyawa kompleks2 penting

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### Uv vis spektra senyawa kompleks2 penting

1. 1. Analisis spektra UV-Vis senyawa kompleks
2. 2. Warna senyawa kompleks
3. 3. Konfigurasi elektronik atom multi-elektron Apakah makna konfigurasi 2p2 ? n = 2; l = 1; ml = -1, 0, +1; ms = ± 1/2 Penataan elektron yang sesuai microstatesbeda energi karena tolakan antar elektron (inter-electronic repulsions)
4. 4. Konfigurasi elektronik atom multi-elektron  pasangan RS Russell-Saunders (or LS) coupling Untuk tiap atom multi-elektronUntuk tiap elektron 2p L = total orbital angular momentum quantum number n = 2; l = 1 S = total spin angular momentum quantum number ml = -1, 0, +1 Spin multiplicity = 2S+1 ms = ± 1/2 ML = ∑ml (-L,…0,…+L) MS = ∑ms (S, S-1, …,0,…-S) • ML/MS menyatakan microstates • L/S menyatakan states (kumpulan microstates) • Group microstates dengan energi yang sama disebut terms
5. 5. Menentukan microstates untuk p2
6. 6. Spin multiplicity = 2S + 1
7. 7. Menentukan harga L, ML, S, Ms untuk terms yang berbeda 1 S2 P
8. 8. Mengklasifikasikan microstates p2 Largest ML is +2, so L = 2 (a D term) and MS = 0 for ML = +2, 2S +1 = 1 (S = 0) 1 D Next largest ML is +1, so L = 1 (a P term) and MS = 0, ±1 for ML = +1, 2S +1 = 3 3 P One remaining microstate ML is 0, L = 0 (an S term) and MS = 0 for ML = 0,Spin multiplicity = # columns of microstates 2S +1 = 1 1 S
9. 9. Next largest ML is +1, Largest ML is +2, so L = 1 (a P term) so L = 2 (a D term) and MS = 0, ±1 for ML = +1,and MS = 0 for ML = +2, 2S +1 = 3 2S +1 = 1 (S = 0) 3 P 1 D ML is 0, L = 0 2S +1 = 1 1 S
10. 10. Energy of terms (Hund’s rules) Lowest energy (ground term) Highest spin multiplicity 3 P term for p2 case 3 P has S = 1, L = 1 If two states havethe same maximum spin multiplicity Ground term is that of highest L
11. 11. before we did:p2 ML & M S the largest ML L spin multiplicity = Σcolumns or 2S+1, S the largest MS Microstate Table Spin multiplicity States (S, P, D) 3 P, 1D, 1S Terms Ground state term 3 P
12. 12. single e- (electronic state)  multi-e- (atomic state)
13. 13. For metal complexes we need to consider d1-d10 d2 3 F, 3P, 1G, 1D, 1SFor 3 or more electrons, this is a long tedious process But luckily this has been tabulated before…
14. 14. Transitions between electronic terms will give rise to spectra
15. 15. Remember what we’re after ?Theory to explain electronicexcitations/transitions observed for metalcomplexes
16. 16. Selection rules (determine intensities) Laporte rule g → g forbidden (that is, d-d forbidden) but g → u allowed (that is, d-p allowed) Spin rule Transitions between states of different multiplicities forbidden Transitions between states of same multiplicities allowedThese rules are relaxed by molecular vibrations, and spin-orbit coupling
17. 17. Breakdown of selection rules
18. 18. Group theory analysis of term splitting
19. 19. Free ion term for d23 F, 3P, 1G, 1D, 1S Real complexes
20. 20. Tanabe-Sugano diagrams• show correlation of spectroscopic transitions observed for ideal Oh complexes with electronic states• energy axes are parameterized in terms of Δo and the Racah parameter (B) which measures repulsion d2 between terms of the same multiplicity
21. 21. d2 complex: Electronic transitions and spectra only 2 of 3 predicted transitions observed
22. 22. TS diagrams Other dn configurations d3d1 d9 d2 d8
23. 23. Other configurations d3 The limit betweenhigh spin and low spin
24. 24. the spectra of dn hexaaqua complexes of 1st row TMs
25. 25. The d5 caseAll possible transitions forbidden Very weak signals, faint color
26. 26. symmetry labels
27. 27. Charge transfer spectra Metal character LMCTLigand character Ligand character MLCT Metal character Much more intense bands
28. 28. [Cr(NH3)6]3+
29. 29. Determining ∆o from spectrad1 d9 One transition allowed of energy ∆o
30. 30. Determining ∆o from spectramixingmixing Lowest energy transition = ∆o
31. 31. Ground state mixing E (T1g→A2g) - E (T1g→T2g) = ∆o