1
SUPPLEMENTARY MATERIAL
Derivatives of benzo[b]furan. Part I. Conformational studies of khellinone and visnaginone
Tomás Peña Ruiza, Aleksandra Drzewieckab,c, Anna E. Koziolb, Manuel Fernández Gómeza,
Kinga Ostrowskad,e, Marta Strugae, Jerzy Kossakowskie
aDepartment of Physical and Analytical Chemistry, University of Jaen, 23071 Jaen, Spain
bFaculty of Chemistry, Maria Curie-Sklodowska University, 23-031 Lublin, Poland
cInstitute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland
dDepartment of Organic Chemistry, Faculty of Pharmacy, Medical University of Warsaw, 02-097 Warsaw, Poland
e Department of Medicinal Chemistry, Faculty of Medicine I, Medical University of Warsaw, 02-007 Warsaw, Poland
Intramolecular hydrogen bond
The stability of the intramolecular hydrogen bond between the acetyl and hydroxyl groups in molecules 1 and 2 (Fig. 1) has also been analysed. The energy surface for the rotation of –OH and –C(=O)CH3 (Fig. 1S) has been explored by rotation of the torsion angles t3(O3-C9-C5-C6) and t4(H4-O4-C6-C5) respectively. Thus, the rotation of the acetyl group (t3, Fig. 1S-left) does not produce any new stable conformer and involves a barrier to rotation around 18 Kcal/mol for both molecules irrespective the selected functional. Changing t4 (Fig. 1S-right), two new stable conformers are obtained for 1 with an intramolecular hydrogen bond between the hydroxyl group and methoxy group at C7; at t4=-180º, both B3LYP and B1B95 yield the same conformer but at t4=+180º the conformers are different, then the conformer obtained by B3LYP involves a stabilizing intramolecular interaction between the carbonyl group and a hydrogen atom of the methoxy group C4-OCH3. This interaction does not appear initially with B1B95 but it has been tested that additional rotation steps of the acetyl group produce such a result. These new minima do not influence the conformational equilibrium previously described since they are rather unstable respect to most stable analysed conformers (the structures of the new conformers can be requested via e-mail to the corresponding author). For visnaginone2 most stable structure, only one additional minimum appears without any intramolecular hydrogen bond. As it is observed in Figure 1S-right, the barriers to rotation are in the range 14-17 Kcal/mol for 1 irrespective of the functional while for 2 it amounts to ca. 16 kcal/mol
The barrier to rotation for the acetyl group has been used as a reference for the estimation of the strength of the intramolecular hydrogen bond since it does not produce any new conformer involving other intramolecular hydrogen bonds and the maximum does not contain them too. Table 1S reports the values of the barrier to torsion for t3 by using several approaches. Thus, it is observed that both B3LYP and B1B95 functionals yield similar values. In order to take into account the basis set superposition error (BSSE), unrestricted calculations have to be conducted. Wehave checked also that the UB3LYP/6-31G(d)//RB3LYP/6-31G(d) approach does not substantially modify the value of the barrier. As it is reported, the BSSE is almost insignificant, 0.3 Kcal/mol for UB3LYP/6-31G(d). The approach UB3LYP/aug-cc-pVDZ//RB3LYP/6-31G(d) decreases the barrier to rotation by ca 0.9 Kcal/mol (the BSSE for this approximation is lower than 0.1 Kcal/mol). Visnaginone2 exhibits similar results. Thus, it can be summarized that the strength of the intramolecular hydrogen bond on the basis of the rotation of the acetyl group is ca 18 Kcal/mol.
NBO analysis supports the high stability of the commented structural motif despite the values for the second order contributions and those arising from their deletion are clearly overestimated.
Test of the theoretical approaches
Once the exploration of the TES for the rotation of the methoxy groups has been done to find all minima, an evaluation of the performance for the different theoretical methods has been conducted. Thus, the calculated geometry of the most stable conformers for 1 and 2, namely 1a and 2a, are compared to the molecular structure observed in solid phase. Root Mean Square (RMS) deviations were calculated for each type of geometrical parameter (bond length, bond angle and torsion angle):
Differences between values of parameters calculated (xcalc) and measured in solid or gas phase (xexp) were analyzed (i.e. for bond distances, bond angles and torsion angles). Three theoretical methods were used, two DFT functionals (B3LYP and B1B95) and one ab-initio MP2.
The B1B95/6-31G(d) approach yields the closest values to the experimental bond distances, 0.011 Å (1a) (Table 3S, supplementary) and both B1B95 and B3LYP functionals with the 6-31G(d) basis set, give similar and relatively low RMSs for bond angles (0.5º and 0.4º, respectively, 1a). The torsion angles deserve some further explanations. The calculated RMS for the DFT/6-31G(d) is6º (1a) when the torsional angle t2 is consider. Once this parameter is removed (as the main factor of discordance between experimental and calculated geometries) the RMS decreases to 2º for 1a and 2a.
The ab-initio MP2(full)/6-31G(d) approach gives higher values of RMS for each parameter type. In addition, it is observed that ab-initio approach distorts the planarity of the benzene ring up to 3º for some torsional angles (Tables 3S and 4S).Thus, the MP2(full) method has been excluded from the conformational analysis in the liquid phase and the vibrational studies.
The B3LYP method better simulates the vibrational spectrum than B1B95 approach (Figure 2S). Thus, B3LYP functional has been chosen to test the widely implemented basis sets [6-31G(d), 6-31+G(d), 6-31+G(d,p), 6-311++G(d,p)] in predicting the geometry of molecules 1 and 2. The RMS values for bond distances and bond angles do not change with increasing the basis set size, only the RMS for torsion angle for 1 becomes lower for 6-311++G(d,p). This basis set yields t2=-7.8º, this value is closer to the value of torsional angle observed in solid. Thus, the energy surface for both t1 and t2 for 1 have been also calculated with B3LYP/6-311++G(d,p) approximation to investigate this discrepancy. In the TES for t1, only an increase of the barriers to torsion is observed respect to B3LYP/6-31G(d) (Fig. 5). In the TES for t2, the position of both minima and maxima are roughly the same with B3LYP/6-311++G(d,p), but a decrease of both barriers to torsion and relative energy among the stable conformers are observed (Figure 7). It can be considered that both approaches, B3LYP/6-31G(d) and B3LYP/6-311++G(d,p), lead to the same qualitative result, i. e. there is a high degree of freedom for the rotation of the C4–OCH3 group.
Table 1S. Methods used for the estimation of the relative energy E [Kcal/mol] for the intramolecular O-H…O hydrogen bond.
1 / ERB3LYP/6-31G(d) / 17.8
2 / E
RB3LYP/6-31G(d) / 18.3 / NBO / E
UB3LYP/6-31G(d) / 18.3 / LP(1)O136 BD*(1)O10-H11 / 6.6
UB3LYP/6-31G(d)+BSSE / 18.0 / LP(2)O136 BD*(1)O10-H11 / 37.8
RB3LYP_adz* / 17.4 / Deletion / 48.4
RB1B95/6-31G(d) / 17.9
* _adz: aug-cc-DZP
Table 2S. Vibrational assignment for visnaginone 2
Experimental frequencies (cm-1) / Scaled theoretical frequencies (cm-1) / Description*IR_Gas / IR_Solid / Raman_Solid / t2=0º / t2=-70º
3160 / 3150 / 3150 / 3180 / 3171 / C(Fur)-H sym str.
3133 / 3124 / 3125 / 3160 / 3144 / C(Fur)-H asym str.
3070 / 3070 / 3117 / 3115 / Str. C(phenyl)-H
2998 / 3058 / -OH Str.S
3003 / 3005 / 3039 / 3042 / C(methyl)-H asym str.
3030 / 3030 / C(methyl)-H asym str.
3015 / 3015 / C(methyl)-H asym str.
3009 / -OH Str.
2995 / 2980 / C(methyl)-H asym str.
2954 / 2958 / 2960 / 2949 / 2949 / C(methyl)-H sym str.
2954 / 2931 / 2930 / 2924 / 2914 / C(methyl)-H sym str.
1627 / 1623 / 1639 / 1641 / C=O Str., Phenyl ring str.-def.
1593 / 1605 / 1615 / 1621 / C=O Str., Phenyl ring str.-def.
1585 / 1581 / 1581 / 1581 / Phenyl ring str., C-O-H def.
1549 / 1548 / 1552 / 1542 / Fur. Ring str., C(Fur)-H rocking
1472 / 1471 / 1478 / 1474 / 1473 / Methyl(methoxy) asym. def.
1455 / 1463 / 1462 / Methyl(methoxy) sym. def.
1450 / 1460 / 1451 / Methyl(methoxy) asym. def.
1442 / 1441 / 1442 / Methyl(acetyl) asym. Def.
1439 / 1437 / C-O-H def. str. C-OH
1427 / 1429 / 1427 / 1428 / Methyl(methoxy) sym. def.
1417 / 1421 / 1418 / 1420 / Methyl(acetyl) asym. Def.
1386 / 1388 / 1388 / 1385 / Benzofuran Ring Str.
1368 / 1367 / 1374 / 1363 / 1365 / Methyl(acetyl) sym. Def.
1354 / 1353 / 1356 / 1350 / 1347 / Methyl(acetyl) sym. Def., Benzofuran Ring Str.
1293 / 1298 / 1291 / 1295 / rocking C(Fur)-H
1277 / 1273 / 1283 / 1290 / Str. C-OH, C-C(acetyl) str.
Table 2S cont. Vibrational assignment forvisnaginone 2
Experimental frequencies (cm-1) / Scaled theoretical frequencies (cm-1) / Description*IR_Gas / IR_Solid / Raman_Solid / t2=0º / t2=-70º
1256 / 1267 / 1250 / 1247 / Phenyl ring str.
1209 / 1211 / 1209 / 1207 / 1194 / Methyl(methoxy) rocking
1180 / 1186 / 1193 / 1179 / 1183 / Rocking C(phenyl)-H
1152 / 1162 / 1161 / 1163 / 1154 / fur. ring str. C-O , rocking C(fur)-H | rocking methyl(methoxy)S
1135 / 1145 / 1144 / 1152 / 1146 / rocking methyl(methoxy) | Fur. ring str.-def.S
1148 / 1134 / rocking methyl(methoxy) | Fur. Ring def., rocking C(fur)-HS
1091 / 1107 / 1106 / 1105 / 1078 / Fur. Ring def., str O-C(methyl)
1056 / 1058 / 1059 / 1055 / Fur. Ring str.-def.
1028 / 1034 / 1036 / 1041 / 1034 / Fur. Ring str.-def. | Rocking methyl(acetyl)S
1024 / 1036 / 1022 / Rocking methyl(acetyl) | Fur. Ring str.-def.S
973 / 981 / 983 / 973 / 960 / Str. O-C(methyl), rocking methyl(acetyl)
950 / 954 / 955 / 940 / 933 / Rocking methyl(acetyl), str. C(phenyl)-(acetyl)
908 / 908 / 908 / 911 / 910 / Fur. Ring def.
849 / 858 / 849 / 847 / 845 / Fur. Ring str.-def | Asym. Opl C(Fur)-H, Fur. Ring str.S
844 / Asym. Opld C(Fur)-H, Fur. Ring str.S
818 / 829 / 824 / 835 / 835 / Asym. Opl C(Fur)-H | Opl C(phenyl)-H, Opl C-OHS
824 / Opl C(phenyl)-H, Opl C-OH
761 / 772 / 762 / 762 / 760 / Fur. Ring def., rocking C-OCH3
763 / 736 / 753 / Sym. Opl. C(Fur)-H, phenyl ring def.
736 / 745 / 786 / 771 / HO- torsion
703 / 706 / 712 / 731 / Phenyl ring def., Opl. C-OCH3, Opl. C-C(acetyl)
688 / 682 / 685 / 690 / 693 / Opl. C-OH, Phenyl ring def., Opl. C-C(acetyl)
672 / 673 / 668 / Acetyl def., C(acetyl)-CH3 str., rocking C-OH
635 / 635 / 635 / 622 / 651 / Opl -OCH3, opld -OH, phenyl ring tors., butterfly
584 / 588 / 589 / 581 / 577 / Acetyl def., phenyl ring def.
582 / 581 / 576 / 575 / Opl C(acetyl)-C(phenyl), opl -OH, Fur ring tors.
568 / 569 / 559 / 563 / Fur. Ring tors.
542 / 549 / 550 / 546 / 541 / Phenyl ring def., acetyl def., rocking -OH
Table 2S cont. Vibrational assignment for visnaginone2
Experimental frequencies (cm-1) / Scaled theoretical frequencies (cm-1) / Description*IR_Gas / IR_Solid / Raman_Solid / t2=0º / t2=-70º
425 / 416 / 414 / Rocking C(acetyl)-C(phenyl), rocking -OH, rocking C(phenyl)-C(acetyl)
398 / 400 / 394 / Rocking C(acetyl)-C(phenyl), rocking -OH, rocking C(phenyl)-C(acetyl)
372 / 369 / 357 / C-O-CH3 def, phenyl ring def.
347 / 332 / 330 / Rocking C(acetyl)-C(phenyl), phenyl ring def.
335 / 326 / 322 / butterfly, phenyl ring tors.
315 / 296 / 296 / Opl acetyl, phenyl ring tors
274 / 269 / Methyl(methoxy) tors
260 / 261 / 237 / Rocking C(phenyl)-C(acetyl), rocking C-OCH3
230 / 234 / 203 / Methyl(acetyl) tors
230 / 226 / 160 / Rocking C(phenyl)-C(acetyl), rocking C-OCH3
197 / 186 / 138 / butterfly, phenyl ring tors.
162 / 142 / 125 / Phenyl ring tors, -OH tors.
87 / 89 / -OH tors, acetyl tors
45 / 85 / C-OCH3 tors., Methyl(methoxy) tors
34 / 42 / Methyl(methoxy) tors, acetyl tors
*The description of the normal modes is based on the Potential Energy Distribution matrix for the most stable conformer, t2=0º. For those bands interesting for the conformational analysis with a significant difference in the description of the modes respect to the most stable conformer, the description of the modes for the secondary minima has been also included.
S: The symbol “|” and superindex “S” indicate that the description corresponds to the secondary minima.
a Opl: Out of plane deformations
Table 2S. Geometric data for khellinone. Bond distances (Å) and angles (°) formost stable conformer 1a.
Parameter / solid / MP2(full) / B1B95 / B3LYP6-31G(d) / 6-31G(d) / 6-31+G(d) / 6-31+G(d,p) / 6-311++G(d,p)
r(C2-O1) / 1.380 / 1.377 / 1.364 / 1.376 / 1.377 / 1.377 / 1.375
r(C3-C2) / 1.327 / 1.359 / 1.344 / 1.350 / 1.352 / 1.352 / 1.348
r(C3A-C3) / 1.449 / 1.437 / 1.450 / 1.457 / 1.458 / 1.458 / 1.457
r(C4-C3A) / 1.398 / 1.395 / 1.399 / 1.405 / 1.406 / 1.405 / 1.402
r(C5-C4) / 1.411 / 1.410 / 1.420 / 1.429 / 1.430 / 1.430 / 1.427
r(C6-C5) / 1.436 / 1.437 / 1.435 / 1.445 / 1.446 / 1.446 / 1.443
r(C7-C6) / 1.383 / 1.403 / 1.396 / 1.404 / 1.404 / 1.404 / 1.402
r(C7A-C7) / 1.378 / 1.390 / 1.381 / 1.386 / 1.387 / 1.387 / 1.384
r(O5-C7) / 1.378 / 1.366 / 1.359 / 1.368 / 1.368 / 1.367 / 1.365
r(C11-O5) / 1.405 / 1.439 / 1.420 / 1.432 / 1.436 / 1.437 / 1.436
r(O4-C6) / 1.347 / 1.354 / 1.330 / 1.339 / 1.341 / 1.339 / 1.337
r(C9-C5) / 1.476 / 1.483 / 1.472 / 1.478 / 1.479 / 1.477 / 1.478
r(O3-C9) / 1.240 / 1.247 / 1.239 / 1.247 / 1.249 / 1.251 / 1.243
r(C10-C9) / 1.491 / 1.508 / 1.505 / 1.515 / 1.514 / 1.512 / 1.511
r(O2-C4) / 1.344 / 1.382 / 1.349 / 1.360 / 1.360 / 1.360 / 1.358
r(C8-O2) / 1.397 / 1.434 / 1.408 / 1.420 / 1.423 / 1.424 / 1.424
a(C3-C2-O1) / 112.2 / 112.5 / 112.3 / 112.2 / 112.0 / 112.0 / 112.0
a(C3A-C3-C2) / 106.9 / 105.6 / 106.3 / 106.5 / 106.6 / 106.6 / 106.6
a(C4-C3A-C3) / 138.0 / 135.1 / 138.4 / 138.1 / 137.9 / 137.9 / 137.8
a(C5-C4-C3A) / 119.6 / 119.8 / 119.9 / 119.8 / 119.8 / 119.7 / 119.7
a(C6-C5-C4) / 119.3 / 118.9 / 119.3 / 119.1 / 118.9 / 119.1 / 119.1
a(C7-C6-C5) / 121.6 / 121.7 / 121.5 / 121.6 / 121.8 / 121.7 / 121.7
a(C7A-C7-C6) / 116.3 / 116.5 / 116.3 / 116.3 / 116.2 / 116.2 / 116.2
a(O5-C7-C6) / 122.6 / 123.0 / 122.8 / 123.1 / 123.1 / 123.2 / 123.1
a(C11-O5-C7) / 114.5 / 113.1 / 114.6 / 115.5 / 116.0 / 116.0 / 116.1
a(O4-C6-C5) / 121.4 / 122.9 / 122.6 / 122.2 / 122.2 / 121.7 / 121.9
a(C9-C5-C4) / 123.3 / 122.7 / 123.4 / 123.6 / 123.5 / 123.7 / 123.7
a(O3-C9-C5) / 119.6 / 120.3 / 120.2 / 120.3 / 120.0 / 119.9 / 119.9
a(C10-C9-O3) / 116.3 / 117.2 / 115.9 / 115.9 / 116.0 / 116.0 / 116.2
a(O2-C4-C3A) / 124.3 / 118.4 / 124.2 / 124.3 / 124.2 / 124.3 / 124.3
a(C8-O2-C4) / 121.9 / 111.9 / 120.8 / 121.5 / 121.9 / 121.8 / 121.8
Table 2S cont. Geometric data for khellinone. Torsion angles (°) formost stableconformer 1a.
Parameter / solid / MP2(full) / B1B95 / B3LYP6-31G(d) / 6-31G(d) / 6-31+G(d) / 6-31+G(d,p) / 6-311++G(d,p)
t(C3A-C3-C2-O1) / 0.3 / 0.8 / 0.1 / 0.1 / 0.1 / 0.1 / 0.1
t(C4-C3A-C3-C2) / 179.7 / -176.7 / -179.5 / -179.5 / -179.8 / -179.7 / -179.3
t(C5-C4-C3A-C3) / 179.6 / 177.6 / 179.8 / 179.7 / 180.0 / 179.9 / 179.1
t(C6-C5-C4-C3A) / -0.9 / -1.2 / 0.5 / 0.5 / 0.8 / 0.7 / 0.5
t(C7-C6-C5-C4) / 1.6 / 1.1 / -1.0 / -1.0 / -1.6 / -1.5 / -1.1
t(C7A-C7-C6-C5) / -1.1 / -2.7 / 0.6 / 0.6 / 1.4 / 1.3 / 1.0
t(O5-C7-C6-C5) / 175.5 / 177.0 / 177.4 / 177.0 / 176.5 / 176.5 / 176.5
t(C11-O5-C7-C6) / 83.3 / 70.0 / 71.4 / 70.1 / 70.6 / 69.4 / 69.9
t(O4-C6-C5-C4) / -179.2 / 178.9 / 179.1 / 179.1 / 178.5 / 178.6 / 178.8
t(C9-C5-C4-C3A) / 177.9 / -176.1 / -180.0 / -179.9 / -179.8 / -180.0 / 179.9
t(O3-C9-C5-C4) / 175.8 / -173.6 / -179.2 / -179.3 / -178.2 / -178.5 / -179.0
t(C10-C9-O3-C5) / -178.4 / 178.7 / 179.8 / 179.8 / 179.7 / 179.8 / 179.9
t(O2-C4-C3A-C3) / 1.6 / -4.1 / -0.2 / -0.2 / -0.1 / -0.1 / -0.3
t(C8-O2-C4-C3A) / -16.4 / -77.5 / -0.5 / -0.9 / -0.5 / -1.0 / -7.8
Table 3S. Geometric data for visnaginone. Bond distances (Å) and angles (°) formost stable conformer 2a.
Parameter / solid / MP2(full) / B1B95 / B3LYP6-31G(d) / 6-31G(d) / 6-31+G(d) / 6-31+G(d,p) / 6-311++G(d,p)
r(C2-O1) / 1.382 / 1.377 / 1.365 / 1.377 / 1.378 / 1.378 / 1.376
r(C3-C2) / 1.317 / 1.359 / 1.344 / 1.350 / 1.352 / 1.352 / 1.348
r(C3A-C3) / 1.458 / 1.437 / 1.450 / 1.457 / 1.458 / 1.458 / 1.457
r(C4-C3A) / 1.395 / 1.395 / 1.400 / 1.406 / 1.407 / 1.406 / 1.404
r(C5-C4) / 1.418 / 1.409 / 1.420 / 1.430 / 1.431 / 1.431 / 1.428
r(C6-C5) / 1.428 / 1.439 / 1.437 / 1.446 / 1.447 / 1.447 / 1.444
r(C7-C6) / 1.378 / 1.394 / 1.389 / 1.396 / 1.396 / 1.396 / 1.393
r(C7A-C7) / 1.374 / 1.383 / 1.374 / 1.379 / 1.379 / 1.380 / 1.376
r(O4-C6) / 1.348 / 1.352 / 1.328 / 1.337 / 1.340 / 1.337 / 1.336
r(C9-C5) / 1.470 / 1.483 / 1.471 / 1.477 / 1.479 / 1.476 / 1.478
r(O3-C9) / 1.244 / 1.246 / 1.239 / 1.247 / 1.249 / 1.250 / 1.242
r(C10-C9) / 1.488 / 1.508 / 1.505 / 1.515 / 1.514 / 1.513 / 1.512
r(O2-C4) / 1.341 / 1.382 / 1.347 / 1.358 / 1.358 / 1.358 / 1.356
r(C8-O2) / 1.409 / 1.434 / 1.409 / 1.421 / 1.424 / 1.425 / 1.424
a(C3-C2-O1) / 112.6 / 112.5 / 112.2 / 112.1 / 111.9 / 111.9 / 111.9
a(C3A-C3-C2) / 106.8 / 105.5 / 106.2 / 106.5 / 106.5 / 106.5 / 106.5
a(C4-C3A-C3) / 138.3 / 135.3 / 138.5 / 138.2 / 138.1 / 138.1 / 138.0
a(C5-C4-C3A) / 119.9 / 120.2 / 120.3 / 120.2 / 120.2 / 120.1 / 120.1
a(C6-C5-C4) / 118.6 / 118.4 / 118.8 / 118.6 / 118.4 / 118.6 / 118.6
a(C7-C6-C5) / 122.4 / 121.8 / 121.5 / 121.6 / 121.9 / 121.8 / 121.8
a(C7A-C7-C6) / 116.0 / 116.7 / 116.7 / 116.7 / 116.6 / 116.5 / 116.7
a(O4-C6-C7) / 116.5 / 115.7 / 116.4 / 116.4 / 116.2 / 116.7 / 116.5
a(C9-C5-C6) / 118.3 / 118.8 / 117.7 / 117.6 / 117.9 / 117.6 / 117.6
a(O3-C9-C5) / 119.5 / 120.3 / 120.2 / 120.2 / 119.9 / 119.8 / 119.9
a(C10-C9-O3) / 116.2 / 117.3 / 115.9 / 115.9 / 116.0 / 116.1 / 116.2
a(O2-C4-C3A) / 124.3 / 118.3 / 124.0 / 124.1 / 124.0 / 124.1 / 124.1
a(C8-O2-C4) / 121.7 / 112.0 / 120.9 / 121.7 / 122.0 / 121.9 / 122.0
Table 3S. Geometrical data for visnaginone. Torsion angles (°) formost stable conformer 2a.
Parameter / solid / MP2(full) / B1B95 / B3LYP6-31G(d) / 6-31G(d) / 6-31+G(d) / 6-31+G(d,p) / 6-311++G(d,p)
t(C4-C3A-C3-C2) / 178.2 / -179.0 / 180.0 / 180.0 / 180.0 / 180.0 / 180.0
t(C5-C4-C3A-C3) / -176.4 / -178.6 / 180.0 / 180.0 / 180.0 / 180.0 / 180.0
t(C6-C5-C4-C3A) / -0.1 / -4.2 / 0.0 / 0.0 / 0.0 / 0.0 / 0.0
t(C7-C6-C5-C4) / -1.2 / 3.5 / 0.0 / 0.0 / 0.0 / 0.0 / 0.0
t(C7A-C7-C6-C5) / 1.4 / -1.9 / 0.0 / 0.0 / 0.0 / 0.0 / 0.0
t(O4-C6-C7-C7A) / -179.5 / 179.4 / 180.0 / 180.0 / 180.0 / 180.0 / -180.0
t(C9-C5-C6-C7) / 178.3 / -176.1 / 180.0 / 180.0 / 180.0 / 180.0 / 180.0
t(O3-C9-C5-C6) / 3.8 / -9.8 / 0.0 / 0.0 / 0.0 / 0.0 / 0.0
t(C10-C9-O3-C5) / 179.5 / -178.1 / -180.0 / 180.0 / 180.0 / 180.0 / -180.0
t(O2-C4-C3A-C7A) / 179.0 / -179.0 / 180.0 / 180.0 / 180.0 / 180.0 / 180.0
t(C8-O2-C4-C3A) / 15.9 / 79.0 / 0.0 / 0.0 / 0.0 / 0.0 / 0.0
Figure 1S. Energy surface for the rotation of the acetyl (left) and hydroxyl (right) groups of molecules 1 and 2.
Figure 2S.Preliminary comparison of the visnaginone2 experimental IR gas-phase spectrum with the theoretical ones for B1B95/6-31G(d) and B3LYP/6-31G(d). Region 1400-1000 cm-1.
1
Fig. 3SLeft column: IR spectra for 2. Right column: 2nd derivative. Row A: Gas phase. Row B: solid phase. Row C: black/solid line – conformer 2a, red/dashed – line conformer 2b.