Tables. For. Organic Structure Analysis

Transcription

1 Tables For Organic Structure Analysis prepared by Prof. Marcel Jaspars

2 Magnetic properties of commonly studied species. Nucleus Natural abundance (%) Approximate sensitivity at constant Bo for natural abundance 1 Resonance frequency at 2.35 T (100 Mz) Relative magnetic moment ( ) Relative quadrupole moment (Q) I = 1/2 [2] * *13C x N a x *19F Si a x *31P Free electrona 65, I = 0 [0] 12C O Si Si S S 4.4 I = 1 [3] x N x I = 3/2 [4] 11B Na S x Cl x Cl x Br Br I = 5/2 [6] 17O a x I I = 3 [7] 10B x [ ] Number of energy levels. a Negative magnetic moment. * Most useful. 1 Data from Bruker Almanac adjusted for natural abundance

3 Some useful NMR solvents Solvent 1 (ppm) (mult.) 13C (ppm) (mult.) (1) 20.0 (7) Liquid Range ( C) Dielectric Constant OD (ppm) in 1 NMR Acetic Acid-d (1) 2.04 (5) Acetone-d (5) (13) (7) Acetonitrile-d (5) (1) (7) Benzene-d (1) (3) Chloroform-d 7.27 (1) 77.2 (3) Cyclohexane-d (1) 26.4 (5) D2O Dichloromethane-d (3) 54.0 (5) p-dioxane-d (m) 66.7 (5) DMF-d (1) 2.92 (5) 2.75 (5) (3) 34.9 (7) 29.8 (7) DMSO-d (5) 39.5 (7) Methanol-d (1) 49.2 (7) (5) Pyridine-d (1) 7.58 (1) 7.22 (1) (3) (3) (5) TF-d (1) 1.73 (1) Toluene-d (m) 7.00 (1) 6.98 (m) 2.09 (5) 67.6 (5) 25.4 (1) (1) (3) (3) (3) 20.4 (7) TFA-d (1) (4) (4)

4 1 NMR shifts of common impurities in various solvents ( ppm (mult)) Impurity Chloroform-d DMSO-d6 Pyridine-d5 Benzene-d6 D2O Acetic Acid 2.13 (s) 1.95 (s) 2.13 (s) 1.63 (s) 2.16 (s) Acetone 2.17 (s) 2.12 (s) 2.00 (s) 1.62 (s) 2.22 (s) Acetonitrile 1.98 (s) 2.09 (s) 1.85 (s) 0.67 (s) 2.05 (s) Benzene 7.37 (s) 7.40 (s) 7.33 (s) 7.30 (s) 7.44 (s) t-butanol 1.28 (s) 1.14 (s) 1.37 (s) 1.06 (s) 1.23 (s) Chloroform 7.27 (s) 8.35 (s) 8.41 (s) 6.41 (s) ns Cyclohexane 1.43 (s) 1.42 (s) 1.38 (s) 1.40 (s) ns Dichloromethane 5.30 (s) 5.79 (s) 5.62 (s) 4.46 (s) ns Diethyl Ether 3.48 (q) 3.42 (q) 3.38 (q) 3.27 (q) 3.56 (q) 1.20 (t) 1.13 (t) 1.12 (t) 1.10 (t) 1.17 (t) DMF 8.01 (s) 7.98 (s) 7.91 (s) 2.95 (s) 2.92 (s) 2.72 (s) 2.40 (s) 3.00 (s) 2.88 (s) 2.76 (s) 2.66 (s) 1.98 (s) 2.86 (s) DMSO 2.62 (s) 2.52 (s) 2.49 (s) 1.91 (s) 2.70 (s) p-dioxane 3.70 (s) 3.61 (s) 3.61 (s) 3.38 (s) 3.75 (s) Ethanol 3.72 (q) 3.49 (q) 3.86 (q) 3.39 (q) 3.64 (q) 1.24 (t) 1.09 (t) 1.29 (t) (t) 1.16 (t) Ethyl Acetate 4.12 (q) 4.08 (q) 4.06 (q) 3.91 (q) 4.14 (q) 2.04 (s) 2.02 (s) 1.94 (s) 1.68 (s) 2.08 (s) 1.25 (t) 1.21 (t) 1.10 (t) 0.94 (t) 1.23 (t) Methanol 3.48 (s) 3.20 (s) 3.57 (s) 3.09 (s) 3.35 (s) Petroleum Ether 1.28 (bs) 1.28 (bs) 1.20 (bs) 1.22 (s) ns 0.90 (t) 0.89 (t) 0.86 (t) 0.89 (t) i-propanol 4.03 (m) 4.16 (m) 3.76 (m) 1.22 (d) 1.06 (d) 1.29 (d) 1.01 (d) 1.18 (d) n-propanol 3.60 (t) 3.75 (t) 3.76 (t) 3.61 (t) 1.60 (m) 1.45 (m) 1.70 (m) 1.40 (m) 1.57 (m) 0.93 (t) 0.87 (t) 0.97 (t) 0.80 (t) 0.89 (t) Pyridine 8.60 (m) 8.61 (m) 8.71 (m) 8.50 (m) 8.50 (m) 7.69 (m) 7.83 (m) 7.58 (m) 7.05 (m) 7.90 (m) 7.28 (m) 7.21 (m) 7.21 (m) 6.70 (m) 7.47 (m) TF 3.74 (m) 3.63 (m) 3.67 (m) 3.01 (m) 3.75 (m) 1.85 (m) 1.78 (m) 1.64 (m) 0.87 (m) 1.88 (m) Toluene 7.19 (m) 7.22 (m) 7.22 (m) 7.10 (m) ns 2.34 (s) 2.32 (s) 2.22 (s) 2.13 (s) Triethylamine 2.56 (q) 2.47 (q) 2.43 (q) 2.40 (q) 2.59 (q) 1.03 (t) 0.99 (t) 0.96 (t) 0.95 (t) 1.02 (t) ns=not soluble From: J. Org. Chem. 1997, 62,

5 Characteristics of Important Spectrometric Methods in Common Use -1 C-13 MS IR/RAMAN UV-VIS ORD/CD X-RAY Radiation type RF RF Not relevant IR UV to visible UV to visible X-ray Spectral scale 0-15 ppm ppm amu cm nm nm Not relevant Average sample mg 5 mg 1 mg 1 mg 1 mg 1 mg Single Crystal Molecular formula Partial Partial Yes No No No Yes Functional groups Yes Yes Limited Yes Very Limited Very Limited Yes Substructures Yes Limited Yes Limited Limited No Yes Carbon connectivity Yes Yes No No No No Yes Substituent regiochemistry Substituent stereochemistry Analysis of isomer mixtures Yes Yes No Limited No No Yes Yes Yes No Limited No No Yes Yes Yes Yes (by GC/MS LC/MS) Yes (by GC/IR) No No Yes (if separate) Purity information Yes Yes Yes Yes Limited Limited Limited What is measured Peak areas Chemical shifts Coupling Relaxation Chemical shifts Coupling Relaxation Singly or multiple charged ions Vibrational transitions Electronic transitions [ ] Relative atom positions R/S absolute stereochemistry Typical units (ppm) (ppm) m/z cm -1 nm nm - 5 E A 6 Typical Representations log 4 3 K B ppm (nm) -1, nm ORTEP ppm 1

6 1 NMR Chemical Shifts in Organic Compounds ppm Phenol -O Alcohols-O Thiols-S Amines-N 2 Amides Carboxylic acids-o Aldehydes eteroaromatics O RCONR O 2 C - CO- RCON 2 N Aromatics Z Alkenes Z=O, N, S RC=CR Z 2 2 C=CR 2 -C-O- ó -C-X Alcohols, alogens Amines R-N 2 R -C-N- ó -C 2 -N -C 2 -O- Alkynes ó- C C Methyl groups (R-Me) C 2 -X C 3 -O- C 3 -N C 3 -S- C 3 -Ph C 3 -C-X C 3 -CO- C 3 -C=C- Methylenes (-C 2 -) Ph-C 2 - O -CO-C 2 - -C 2 -C=C- R-C 2 -R 2 C Cyclopropyl Metals (M-C 3 ) M-C 3 ppm Relative to TMS (0 ppm) R O R N 2 N Z Z=O, N, S S R

7 13 C NMR Chemical Shifts in Organic Compounds sp 2 sp sp 3 4 o 3 o 2 o 1 o ppm alogen (C Tertiary) 230 C=O Ketone C=O Aldehyde C=O Acid C=O Ester, Amide C=S Thioketone C=N - Azomethine C=N - eteroaromatic C=C Alkene C=C Aromatic C=C eteroaromatic C C Alkyne C N Nitrile C Quat. C-O- C-N- C-S C-X C-C C-O- C-N- C-S- C-X alogen C 2 -C (C Secondary) C 2 -O- C 2 -N- C 2 -S- C 2 -X alogen C 3 -C (C Primary) C 3 -O- C 3 -N- C 3 -S- C 3 -X alogen ppm Cyclopropanes Epoxides *Relative to TMS (0 ppm) 4 o Quaternary, 3 o Tertiary, 2 o Secondary, 1 o Primary

8 15 N NMR Chemical Shifts in Organic Compounds Aliphatic amine Amonium salt Dimethyleneamine Anilinium ion Aniline ppm Piperidine Cyclic enamine Aminophosphine Guanidine Urea, carbamate, lactame Amide ppm Primary Secondary Tertiary Primary Secondary Tertiary Thiourea Thioamide Nitramine Indole, pyrrole idrazone, triazene Imide Nitrile, isonitrile Pyrrazole Diazocompound Diazonium salt Pyridine Imine Oxime Nitrocompound Nitrosocompound Ar-NO S-NO *Nitrometane as reference (380 ppm) N-NO N=N-N Pyridine Pyrazine Imine Terminal Tertiary Internal Pyrimidine Imidazole Primary Secondary NO 2 Imine Iso N Amine Amine

9 31 P NMR Chemical Shifts in Organic Compounds ppm Z-P=P-Z Z 2 N-P=NR ArP=C=Z 2 ArP=C=Ar ArP=C=Ar 2 ArP=C=O X=P(Y)=Z Z 3 P (TMS) 3 P Cl 3 P (RO) 3 P (Ar) 3 P (Me) 3 P 3 P Z-C P TMS-C P R-C P FC P R 3 -P-R R 2 P-PR 2 Z 3 P=O R 3 P=CR 2 Z 5 P R 2 P - M + Z 6 P - R(OR) 2 P=O Cl(OR) 2 P=O (OR) 5 P R 3 P=O RO 3 P=O Cl 2 RP=O R 2 (OR) 3 P R 4 P ppm *Reference 3 PO 4 85%. Adapted from A Complete Introduction to Modern NMR Spectroscopy. R. S. Macomber. J. Wiley and Sons

10 Symmetry Effects for omotopic; Enantiotopic, and Diasterotopic Groups GROUP A/B Relationships Methylenes Example Appearance 1 RMN Achiral solvent Appearance 1 RMN Chiral solvent omotopic Enantiotopic ppm ppm Diastereotopic ppm ppm Methyls ppm ppm omotopic Enantiotopic ppm ppm Diastereotopic ppm ppm ppm ppm

11 First-order Splitting Patterns of Some Common Spin Systems. Entry Structure Notation and Pattern for a Entry Structure a multiplets J ab =J ac d dd 1 7 b b' J ab > J ab' t t 2 8 ab > 0; b = b' J ab = J ab' t dd 3 9 J ac > J ab q dt 4 10 J ab >J ac q ddd 5 11 J ab >J ab' >J ac sp dq 6 12 J ab > J ac

12 Common Coupled Spin Systems Entry No. spins Spin Type J values by inspection Examples 1 2 AX Yes 2 2 AB Yes 3 3 AMX ABX ABC Yes J AB and J (AX+BX) None 4 3 A 2 X Yes 5 3 A 2 B Yes 6 4 A 3 X A 3 B Yes Yes 7 4 AMX 2 Yes 8 4 ABX 2 J AB rare ABCX ABCD None None X Y X Y 9 4 A 2 X 2 A 2 B 2 Yes No 10 4 AA'XX' J AX when J AA' or J XX' is small No when large 11 4 AA'BB' No 12 5 A 3 X 2 A 3 B A 3 MX A 3 XY Yes Yes Yes J XY

13 Examples of Magnetic and Chemical Equivalence. Type 1 Group Symmetry Chemical Equivalence Magnetic Equivalence Spectral Type 1 Spectral Appearance C 2 Cl 2 omotopic Yes Yes A ppm C 2 F 2 omotopic Yes Yes A 2 X ppm omotopic Yes Yes A ppm omotopic Yes No AA'XX' ppm omotopic Yes Yes A ppm Two homotopic sets Yes No AA'BB' ppm omotopic vinyl s Yes Yes A 2 X ppm Two homotopic sets Yes No AA'BB' ppm

14 13 C sp 3 Chemical Shifts Increment Values (ppm) a Primary Secondary b Z Tertiary c Z ' Cyclohexyl Z Base values [Z=] CN 3 3-3±1 0± ±2 3± C C ±1-4±2-2±1 C=C ±3 4±1-3±2 0 C 2 C I ±2-2± C 3 9 8±1-1±1-1±1 5±1 9±1-4± ring COO ±1 0±2 0±2 0 14±1 2± C ±1 0 17± ±1 5± CO N ±1-1±2 22±1 7±2-4± COC ±1-3± Br ±2-2±2 28±1 11±1-3±1-1± COCl ±1-1± NR ±1-1± Cl ±1-2± NR ±1-2± O 49±1 10-4±2-1±2 42±3 10±3-4±2-1±1 38± OCOR OR ±2-1±2 48±3 6± F a Some values based on calculated s; b : use 23.2 as base value and -increment; c, : use 29.8 as base values and -increment

15 1 NMR Substituted Double Bond Substituent Increment Values (ppm) a R t =R trans ; R c =R cis ; R g =R geminal Substituent gem cis trans C Alkyl Alkyl ring b C C 2 C C=C 2 (isol) C=C 2 (conj) c C C CN CO COR (isol) COR (conj) c COO (isol) COO (conj) c COCl COOR (isol) COOR (conj) c CON OR OC 6 5, O-conj OCOR C 2 O NR N(C 6 5 ) 2, N(conj) C 2 N NO F C 2 F Cl C 2 Cl Br C 2 Br I C 2 I a Calculate shifts using (C=C) = gem. + cis + trans b Based when the double bond is part of a ring c Used when the substituent or double bond in question is further conjugated to sp 2 systems C. Pascual, J. Meier, W. Simon elv. Chim. Acta 1966, 49, 164

16 13 C NMR Substituted Double Bond Chemical Shift Increment Values (ppm) Substituent X (base value) C C C C C C=C C C CN CO COC COO COCl COOC OC OC OCOC C 2 O N(C 3 ) NO F Cl C 2 Cl Br C 2 Br I C 2 I E. Prestch, A. Fürst, W. Robien Anal. Chim. Acta 1991, 248, 415.

17 1 NMR Benzene Ring Shift Increment Values (ppm) Substituent X (base value) C C C(C 3 ) C(C 3 ) C 2 Cl CF 3 Cl C 2 O C C=C C C CN CO COC COC COC(C 3 ) COO COCl COOC COOPh CON O OC OC OCOC OCOPh OSO 2 C N N(C 3 ) N(C 3 ) NCOC NMeCOC NN NO N=NPh S SC SPh SiMe PO(OMe) F Cl Br I

18 13 C NMR Benzene Ring Shift Increment Values (ppm) X Substituent X C-1 C-2 C-3 C-4 (base value) C C 2 C C 2 C 2 C 2 C C(C 3 ) C(C 3 ) Cyclopropyl Ring C C=C C C CF CCl CN C 2 CN C 2 COO C 2 O C 2 N C 2 Cl C 2 Br C 2 SMe C 2 SOMe C 2 Br CO COC COCF COC COO COO COCl COOC CON CON(C 3 ) O ONa OC OC OC=C OCOC OCN OSiMe OPO(OPh) N N(C 3 ) N(C 3 ) NC N(C 6 5 ) NCOC NO NC NCS S SMe SCMe SPh SOC SO 2 C SO 2 Cl SO SO 2 OMe Si SiMe SnMe F Cl Br I Pretsch, E., Furst, A.; Robien, W. Anal. Chim. Acta 1991, 248,

19 Summary of 2 J Values

20 Summary of 3 J Values J sp 3 carbons Type J(z) Type J(z) Type J(z) C 2 C 3 R OR C 3 C 2 Cl C 3 C 2 Br Cl OR RO OR O N O cis 7 trans 6 cis 5 trans 3 cis 6 trans 4 cis 10 trans 5 cis 9 trans 7 ax eq eq ax ax eq O ax exo endo exo endo cis 6-9 trans 5-7 cis 2-6 trans 7-10 ax - ax =12 ax - eq =4 eq - eq =4 ax - ax =11 ax - eq =4 exo - exo =10 endo - endo =13 endo - endo =4 sp 2 carbons Type J(z) Type J(z) Type J(z) Type J(z) O c c O N b a b a J ab =1.8 J bc =3.4 J ab =2.6 J bc =3.5 c c c c N b a b a b a b a J ab =5.5 J bc = J ab =9.6 J bc =5.1 J ab =7.5 J bc =7.5 J ab =5.5 J bc =7.5 N N O N O N S N c b a J ab =6.8 J bc =8.0 R 1 R 1 X X R 2 R 2 R 1 R X=alogen 7 X=alogen

21 Summary of 3 J Values (cont.)

22 Summary of 4 J and 5 J Coupling Constants