Organic Structure Determination Using 2-D NMR Spectroscopy: A Problem-Based Approach (Advanced Organic Chemistry)

Cover Page......Page 1
Title: Organic Structure Determination Using 2-D NMR Spectroscopy......Page 4
ISBN 0120885220......Page 5
Contents (with page links)......Page 8
Preface......Page 14
1.2 Consequences of Nuclear Spin......Page 16
1.3 Application of a Magnetic Field to a Nuclear Spin......Page 18
1.4 Application of a Magnetic Field to an Ensemble of Nuclear Spins......Page 20
1.5 Tipping the Net Magnetization Vector from Equilibrium......Page 26
1.6 Signal Detection......Page 27
1.8 The 1-D NMR Spectrum......Page 28
1.9 The 2-D NMR Spectrum......Page 30
1.10 Information Content Available Using NMR......Page 31
2.1 Sample Preparation......Page 34
2.1.2 Sample Purity......Page 35
2.1.5 Drying NMR Tubes......Page 36
2.1.7 Sample Volume......Page 37
2.1.8 Solute Concentration......Page 39
2.1.9 Optimal Solute Concentration......Page 41
2.2 Locking......Page 42
2.3 Shimming......Page 43
2.5 Modern NMR Instrument Architecture......Page 44
2.5.2 Probe Tuning......Page 46
2.5.3 When to Tune the NMR Probe and Calibrate RF Pulses......Page 47
2.5.4 RF Filtering......Page 48
2.6 Pulse Calibration......Page 49
2.7 Sample Excitation and the Rotating Frame of Reference......Page 51
2.8 Pulse Roll-off......Page 52
2.9 Probe Variations......Page 54
2.9.2 Flow-Through NMR Probes......Page 56
2.9.3 Cryogenically Cooled Probes......Page 57
2.9.4 Probe Sizes (Diameter of Recommended NMR Tube)......Page 58
2.9.5 Normal Versus Inverse Coil Configurations in NMR Probes......Page 59
2.11 Signal Digitization......Page 60
3.1 Setting the Spectral Window......Page 66
3.2 Determining the Optimal Wait Between Scans......Page 68
3.3 Setting the Acquisition Time......Page 71
3.4 How Many Points to Acquire in a 1-D Spectrum......Page 72
3.5 Zero Filling and Digital Resolution......Page 73
3.6 Setting the Number of Points to Acquire in a 2-D Spectrum......Page 74
3.7 Truncation Error and Apodization......Page 76
3.8 The Relationship Between T[sub(2)]* and Observed Line Width......Page 77
3.9 Resolution Enhancement......Page 79
3.10 Forward Linear Prediction......Page 80
3.11 Pulse Ringdown and Backward Linear Prediction......Page 81
3.12 Phase Correction......Page 82
3.13 Baseline Correction......Page 85
3.14 Integration......Page 86
3.15 Measurement of Chemical Shifts and J-Couplings......Page 88
3.16 Data Representation......Page 91
4.1 The Nature of the Chemical Shift......Page 98
4.2 Aliphatic Hydrocarbons......Page 101
4.4 Olefinic Hydrocarbons......Page 103
4.6 Aromatic Hydrocarbons......Page 105
4.7 Heteroatom Effects......Page 106
5.1 Homotopicity......Page 110
5.2 Enantiotopicity......Page 112
5.3 Diastereotopicity......Page 113
5.5 Magnetic Equivalence......Page 114
6.1 Origin of J-Coupling......Page 116
6.2 Skewing of the Intensity of Multiplets......Page 118
6.3 Prediction of First-Order Multiplets......Page 121
6.4 The Karplus Relationship for Spins Separated by Three Bonds......Page 125
6.5 The Karplus Relationship for Spins Separated by Two Bonds......Page 126
6.7 Decoupling Methods......Page 128
6.8 One-Dimensional Experiments Utilizing J-Couplings......Page 130
6.9 Two-Dimensional Experiments Utilizing J-Couplings......Page 132
6.9.1.1 COSY......Page 133
6.9.1.1.1 Phase Sensitive COSY......Page 134
6.9.1.2 TOCSY......Page 135
6.9.1.3 INADEQUATE......Page 138
6.9.2.1 HMQC and HSQC......Page 139
6.9.2.2 HMBC......Page 147
7.1 The Dipolar Relaxation Pathway......Page 152
7.2 The Energetics of an Isolated Heteronuclear Two-Spin System......Page 153
7.3 The Spectral Density Function......Page 154
7.4 Decoupling One of the Spins in a Heteronuclear Two-Spin System......Page 156
7.5 Rapid Relaxation via the Double Quantum Pathway......Page 157
7.6 A One-Dimensional Experiment Utilizing the NOE......Page 159
7.7.1 NOESY......Page 162
7.7.2 ROESY......Page 163
8 Molecular Dynamics......Page 166
8.1 Relaxation......Page 167
8.3 Slow Chemical Exchange......Page 168
8.4 Intermediate Chemical Exchange......Page 169
8.5 Two-Dimensional Experiments that Show Exchange......Page 171
9 Strategies for Assigning Resonance to Atoms Within a Molecule......Page 172
9.1 Prediction of Chemical Shifts......Page 173
9.3 Prediction of [sup(1)]H Multiplets......Page 174
9.4 Good Bookkeeping Practices......Page 175
9.5 Assigning [sup(1)]H Resonances on the Basis of Chemical Shifts......Page 177
9.6 Assigning [sup(1)]H Resonances on the Basis of Multiplicities......Page 178
9.7 Assigning [sup(1)]H Resonances on the Basis of the gCOSY Spectrum......Page 181
9.8 The Best Way to Read a gCOSY Spectrum......Page 184
9.9 Assigning [sup(13)]C Resonances on the Basis of Chemical Shifts......Page 186
9.10 Pairing [sup(1)]H and [sup(13)]C Shifts by Using the HSQC/HMQC Spectrum......Page 188
9.11 Assignment of Nonprotonated [sup(13)]C's on the Basis of the HMBC Spectrum......Page 193
10 Strategies for Elucidating Unknown Molecular Structures......Page 198
10.1 Initial Inspection of the One-Dimensional Spectra......Page 199
10.2 Good Accounting Practices......Page 202
10.4 Completion of Assignments......Page 206
11.1: 2-Acetylbutyrolactone in CDCl[sub(3)] (Sample 26)......Page 214
11.2: α-Terpinene in CDCl[sub(3)] (Sample 28)......Page 216
11.3: (1R)-endo-(+)-Fenchyl Alcohol in CDCl[sub(3)] (Sample 30)......Page 220
11.4: (–)-Bornyl Acetate in CDCl[sub(3)] (Sample 31)......Page 224
11.5: N-Acetylhomocysteine Thiolactone in CDCl[sub(3)] (Sample 35)......Page 229
11.6: Guaiazulene in CDCl[sub(3)] (Sample 52)......Page 232
11.7: 2-Hydroxy-3-Pinanone in CDCl[sub(3)] (Sample 76)......Page 236
11.8: (R)-(+)-Perillyl Alcohol in CDCl[sub(3)] (Sample 81)......Page 239
11.9: 7-Methoxy-4-Methylcoumarin in CDCl[sub(3)] (Sample 90)......Page 242
11.10: Sucrose in D[sub(2)]O (Sample 21)......Page 245
12.1 Longifolene in CDCl[sub(3)] (Sample 48)......Page 248
12.2 (+)-Limonene in CDCl[sub(3)] (Sample 49)......Page 253
12.3 L-Cinchodine in CDCl[sub(3)] (Sample 53)......Page 256
12.4 (3aR)-(+)-Sclareolide in CDCl[sub(3)] (Sample 54)......Page 261
12.5 (–)-Epicatechin in Acetone-d[sub(6)] (Sample 55)......Page 266
12.6 (–)-Eburnamonine in CDCl[sub(3)] (Sample 71)......Page 270
12.7 trans-Myrtanol in CDCl[sub(3)] (Sample 72/78)......Page 273
12.8 cis-Myrtanol in CDCl[sub(3)] (Sample 73/77)......Page 276
12.9 Naringenin in Acetone-d[sub(6)] (Sample 89)......Page 279
12.10 (–)-Ambroxide in CDCl[sub(3)] (Sample Ambroxide)......Page 283
13.1 Unknown 13.1 in CDCl[sub(3)] (Sample 20)......Page 286
13.2 Unknown 13.2 in CDCl[sub(3)] (Sample 41)......Page 289
13.3 Unknown 13.3 in CDCl[sub(3)] (Sample 22)......Page 293
13.4 Unknown 13.4 in CDCl[sub(3)] (Sample 24)......Page 295
13.5 Unknown 13.5 in CDCl[sub(3)] (Sample 34)......Page 297
13.6 Unknown 13.6 in CDCl[sub(3)] (Sample 36)......Page 300
13.7 Unknown 13.7 in CDCl[sub(3)] (Sample 50)......Page 302
13.8 Unknown 13.8 in CDCl[sub(3)] (Sample 83)......Page 305
13.9 Unknown 13.9 in CDCl[sub(3)] (Sample 82)......Page 308
13.10 Unknown 13.10 in CDCl[sub(3)] (Sample 84)......Page 310
14.1 Unknown 14.1 in CDCl[sub(3)] (Sample 32)......Page 314
14.2 Unknown 14.2 in CDCl[sub(3)] (Sample 33)......Page 317
14.3 Unknown 14.3 in CDCl[sub(3)] (Sample 51)......Page 320
14.4 Unknown 14.4 in CDCl[sub(3)] (Sample 74)......Page 324
14.5 Unknown 14.5 in CDCl[sub(3)] (Sample 75)......Page 327
14.6 Unknown 14.6 in CDCl[sub(3)] (Sample 80)......Page 330
14.7 Unknown 14.7 in ACETONE-d[sub(6)] (Sample 86)......Page 334
14.8 Unknown 14.8 in CDCl[sub(3)] (Sample 87)......Page 337
14.9 Unknown 14.9 in CDCl[sub(3)] (Sample 88)......Page 341
14.10 Unknown 14.10 in CDCl[sub(3)] (Sample 72)......Page 344
C......Page 348
D......Page 349
E......Page 350
F......Page 351
J......Page 353
N......Page 354
P......Page 355
R......Page 357
S......Page 358
T......Page 359
Z......Page 360
Glossary of Symbols......Page 361
C......Page 364
E......Page 366
G......Page 367
H......Page 368
J......Page 369
M......Page 370
O......Page 371
P......Page 372
R......Page 373
S......Page 374
T......Page 375
U......Page 376
Z......Page 377