energy conformer containing it. The vibrational frequency of O16–H23 decreases
from 3,619–3,623 when it is free to 3,400 in conformer 2-a. The other
IHBs engaging an ether O are considerably weaker. For instance, the length of
H23⋯O17 is 2.006–2.037/DF+, 2.083–2.095/HF when H25⋯O19 is also present,
Table 6 Dipole moment of the conformers of muchimangin B in the media considered
Conformer
Dipole moment (debye)
In vacuo
In solution
HF
DF+
In chloroform
In acetonitrile
In water
1-a
4.1662
3.9885
4.7594
5.1087
5.4182
1-b
1.7091
1.3588
1.5993
1.7075
1.7913
1-c
1.9821
1.8086
2.2881
2.5723
2.8092
1-d
1.2802
1.4782
1.7053
1.8188
1.8696
1-e
5.4458
5.4539
6.3211
6.7522
7.0890
1-f
3.1875
2.9062
3.4974
3.8409
4.3157
2-a
7.8440
7.8414
9.1170
9.6765
10.1632
1-g
5.8225
5.5955
6.4401
6.7994
7.0356
1-h
4.4311
5.8656
6.7562
7.1279
7.3608
1-i
3.9327
4.0896
−
a
5.1223
5.4417
2-b
7.2060
7.4112
8.5433
9.0041
9.3447
3-a
7.1609
6.8873
8.1754
8.7262
9.3896
3-b
3.5714
2.8503
3.2916
3.3307
3.5051
3-c
3.5924
3.3345
4.0677
4.4421
4.8917
4
6.8559
7.3908
8.7117
9.1853
9.7601
5-a
3.2392
3.1910
4.0539
4.4051
4.7842
5-b
2.6990
3.7297
4.3824
4.6768
4.9450
6-b
4.7504
3.7297
4.3824
4.6768
4.9450
6-a
7.0239
7.0554
8.4389
9.0318
9.5749
5-c
5.4365
5.2699
6.4487
7.0350
7.5681
6-c
2.0224
2.2156
2.6125
2.7015
2.7775
7
9.8406
10.2365
12.0693
12.7602
13.6835
8
7.5252
7.8278
9.2467
9.8144
10.3495
9-a
9.8322
9.6991
11.5354
12.2909
13.1572
9-b
5.3468
5.4582
6.4969
6.8280
7.2309
9-c
5.0431
5.0250
5.9585
6.2923
6.7949
10
7.8202
8.1286
9.8208
10.5829
11.2538
11-a
4.1903
4.2402
5.3132
5.7960
6.2369
11-b
1.7791
1.4909
1.8078
1.9832
2.1970
11-c
2.4432
2.2783
3.0073
3.4131
3.7158
The results in vacuo are from full optimization HF/6-31G(d,p) calculations and DFT/B3LYP/6-31
+G(d,p) calculations (respectively denoted as HF and DF+ in the column headings). The results in
solution are from PCM DFT/B3LYP/6-31+G(d,p) single point calculations on the in-vacuooptimised DFT/B3LYP/6-31+G(d,p) results
a The calculation in chloroform solution does not converge for this conformer
104
L. Mammino et al.
from 3,619–3,623 when it is free to 3,400 in conformer 2-a. The other
IHBs engaging an ether O are considerably weaker. For instance, the length of
H23⋯O17 is 2.006–2.037/DF+, 2.083–2.095/HF when H25⋯O19 is also present,
Table 6 Dipole moment of the conformers of muchimangin B in the media considered
Conformer
Dipole moment (debye)
In vacuo
In solution
HF
DF+
In chloroform
In acetonitrile
In water
1-a
4.1662
3.9885
4.7594
5.1087
5.4182
1-b
1.7091
1.3588
1.5993
1.7075
1.7913
1-c
1.9821
1.8086
2.2881
2.5723
2.8092
1-d
1.2802
1.4782
1.7053
1.8188
1.8696
1-e
5.4458
5.4539
6.3211
6.7522
7.0890
1-f
3.1875
2.9062
3.4974
3.8409
4.3157
2-a
7.8440
7.8414
9.1170
9.6765
10.1632
1-g
5.8225
5.5955
6.4401
6.7994
7.0356
1-h
4.4311
5.8656
6.7562
7.1279
7.3608
1-i
3.9327
4.0896
−
a
5.1223
5.4417
2-b
7.2060
7.4112
8.5433
9.0041
9.3447
3-a
7.1609
6.8873
8.1754
8.7262
9.3896
3-b
3.5714
2.8503
3.2916
3.3307
3.5051
3-c
3.5924
3.3345
4.0677
4.4421
4.8917
4
6.8559
7.3908
8.7117
9.1853
9.7601
5-a
3.2392
3.1910
4.0539
4.4051
4.7842
5-b
2.6990
3.7297
4.3824
4.6768
4.9450
6-b
4.7504
3.7297
4.3824
4.6768
4.9450
6-a
7.0239
7.0554
8.4389
9.0318
9.5749
5-c
5.4365
5.2699
6.4487
7.0350
7.5681
6-c
2.0224
2.2156
2.6125
2.7015
2.7775
7
9.8406
10.2365
12.0693
12.7602
13.6835
8
7.5252
7.8278
9.2467
9.8144
10.3495
9-a
9.8322
9.6991
11.5354
12.2909
13.1572
9-b
5.3468
5.4582
6.4969
6.8280
7.2309
9-c
5.0431
5.0250
5.9585
6.2923
6.7949
10
7.8202
8.1286
9.8208
10.5829
11.2538
11-a
4.1903
4.2402
5.3132
5.7960
6.2369
11-b
1.7791
1.4909
1.8078
1.9832
2.1970
11-c
2.4432
2.2783
3.0073
3.4131
3.7158
The results in vacuo are from full optimization HF/6-31G(d,p) calculations and DFT/B3LYP/6-31
+G(d,p) calculations (respectively denoted as HF and DF+ in the column headings). The results in
solution are from PCM DFT/B3LYP/6-31+G(d,p) single point calculations on the in-vacuooptimised DFT/B3LYP/6-31+G(d,p) results
a The calculation in chloroform solution does not converge for this conformer
104
L. Mammino et al.