- Email: [email protected]
The rα structure of allene: a study of solvent effects in NMR of oriented molecules
of Molecular Structure, 162 (1987) 333-339 Elsevier Science Publishers B.V., Amsterdam -Printed
Journal
THE r, STRUCTURE OF ALLENE: A STUDY IN NMR OF ORIENTED MOLECULES
P. DIEHL, C. BARALDI, Department (Switzerland)
M. KELLERHALS
of Physics, University
in The Netherlands
OF SOLVENT
EFFECTS
and R. WASSER
of Base& Klingelbergstrasse
82, CH 4056
Base1
(Received 15 June 1987)
ABSTRACT NMR spectra of partially oriented allene in 14 different liquid crystal solvents have been analyzed. The resulting direct couplings corrected for harmonic vibrations were used to determine the restructures. Considerable solvent effects were detected which disappeared, if the data were corrected also for the correlated molecular deformation. A solvent independent restructure which agreed well with IR results, and the interaction parameters of the CH and CC bonds of allene for all the solvents were determined. INTRODUCTION
The forces which orient molecules dissolved in liquid crystals also deform the solute in a correlated way, i.e. the solute structure slightly depends upon the molecular orientation with respect to the liquid crystal director. This correlated deformation contributes to the observed direct couplings and causes a solvent dependence of the molecular structure [l] . Therefore the direct couplings must be corrected not only for harmonic vibrations [2] but also for the deformation. For the corrections the interactions between the liquid crystal and the solute are assumed to be additive segmental interaction tensors corresponding to torques acting on the individual bonds of the solute. The deformation contribution to the coupling depends upon the molecular force constants and the derivatives of the interaction tensors as well as of the direct couplings with respect to the normal coordinates. Obviously these contributions are rather complex and must be calculated by computer. In the interpretation of the observed direct couplings in terms of molecular structure and orientation the bond interaction tensors are introduced as unknown parameters. They are fitted iteratively together with the nuclear coordinates. This increase in the number of unknown parameters can usually be compensated by the use of data combined from several solvents. In this study of allene the five observed direct couplings over-determine the problem. There are two unknown structure parameters and two unknown bond interaction tensor anisotropies (AA) in each liquid crystal. Consequently the solvent effects can be determined separately for each solvent as well as for a combination of solvents. We have studied 14 different 0022-2860/87/$03.50
0 1987 Elsevier Science Publishers B.V.
334
solvents so that 70 direct couplings are available for the determination of two structure parameters and 28 bond interaction tensor anisotropies. A comparison of the results for the individual solvents provides an excellent test of the solvent effect theory. EXPERIMENTAL
Commercially available allene was dissolved in the degassed liquid crystals to which 13C-methane had been added as a reference. The solvents as well as the solute concentrations and the 13C-methane (CH) couplings are summarized in Table 1. Phase 4 and all the ZLI liquid crystals were obtained from Merck, E48 from BDH, HAB and EBBA from Roche. Indirect couplings were taken from the literature [ 31 . The ‘H spectra with ‘3C-satellites were recorded on a Bruker WH-90 DS FT-spectrometer at 90 MHz and analyzed with the computer program LEQUOR [ 41. The resulting direct couplings are summarized in Table 2. For the numbering of nuclei see Fig. 1. Corrections for harmonic vibrations based on a force field from the literature [5] were applied to the direct couplings measured. The percentage harmonic corrections are shown in Table 3. From these couplings the molecular r, structures were determined with the program SHAPE [6]. The direct couplings were then corrected for the correlated deformation and the resulting structures were calculated for the individual solvents. For the analysis the experimental errors of the direct couplings were increased by 0.5 Hz in order to take into account the approximations introduced by the theory of correlated deformation. Finally, the combined data were interpreted by one solvent independent molecular structure and two interaction tensor anisotropies (for the CH and CC bonds) for each solvent. The results of these three different approaches are summarized in Table 4 and compared with IR [7] and ED [S] data. DISCUSSION
The results of the structure analysis are presented graphically in Figs. 2 and 3 in which the distance-ratios r(CH),/r(CC) and also angles (HCH) are plotted as a function of the interaction tensor anisotropy AA for the CH bond of methane in the same solvent. A comparison of the uncorrected data with the data corrected for correlated deformation shows, that the solvent effects on the allene structure are roughly proportional to those on methane. The smallest allene solvent effects nearly coincide with the zero point of the methane interaction tensor anisotropy, as had been suggested earlier for different molecules [9]. The agreement, which means that CH bending is the dominant correlated deformation in allene, becomes more obvious in a plot of AA for the CH bond of allene (Table 5) versus AA for the CH bond of methane (Fig. 4). Again, as in many other molecules [l] , an excellent linear relationship is observed.
335 TABLE
1
Liquid and
solvents (CH) couplings
used this study, Hz) of
measured
of the ahene (in in same solvent=?
crystal solvent
DD
concentration (mol%) ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 Mixture of ZLI 1167 ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
(66 wt%)/EBBA
W-I)
of methane (Hz) -8.59(18) -4.25(37) -2.18(01) -2.18(32) -1.07(22) -0.65(18) 0.03( 24) 0.15(15) 0.65( 29) 0.77(27) 1.49(17) 2.24(23) 7.38(22) 7.75(23)
13 14 24 17 24 16 3.Ba 19 14 14 15 14 23 12
(34 wt%)
%)
aThe D couplings are converted to values referenced to the director by multiplying D by -2 if the orientation of the director is perpendicular to the applied magnetic field. (ZLI 1167, ZLI 2806 and ZLI 3125). The concentration of allene in E 48 is given in
wt% .
TABLE
2
Experimental
direct
coupling
Liquic crystal solvent
D (1,2)
ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 ZLI 1167/EBBA ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
-780.39(4) 1683.27(8) -387.04(2) 878.77(4) 902.52(4) -679.74(4) 1050.00(4) 777.54(3) 1514.08(6) 1432.58(6) 939.78(3) 1173.00(4) 534.28(4) 715.62(4)
constants
of allene in Hz
D (133)
D (1,5)
143.30(4) -307.30(6) 70.79(2) -160.56(5) -165.51(5) 124.01(3) -191.65(5) -141.72(3) -276.47(5) -251.56(5) -171.88(4) -214.34(5) -96.47(5) -130.16(5)
-184.75(17) 405.45(41) -92.31(07) 210.71(18) 224.22(17) -167.50(17) 256.84(36) 191.12(36) 376.39(30) 355.92(36) 237.46(30) 296.13(30) 149.75(20) 193.25(29)
D (1,6)
200.93(14) -430.59(30) 99.16(06) -225.01(14) -231.72(13) 173.55(13) -268.45(28) -198.50(26) -386.42(22) -365.85(26) -240.33(23) -299.56(21) -134.27(13) -181.59(21)
D (197)
65.23(18) -139.75(39) 32.33(07) -72.94(18) -75.17(17) 56.40(17) -87.14(34) -64.64(36) -125.75(30) -118.79(36) -77.83(30) -97.40(30) -43.69(17) -59.10(29)
336
Fig. 1. Numbering of atoms and definition of the coordinate system of aiiene TABLE 3 Harmonic vibration corrections for the direct coupling constants in ailene calculated from a force-field in the literature [ 5 ] Coupling Correction (W)
D (132) +4.10
D (1,3) -0.15
D (195) +8.31
D (196) +3.02
D (197) +0.11
TABLE 4 Solvent effects on the structure of allene, solvent independent structure from a combined analysis of 14 data-sets and comparison with IR and ED results Liquid crystal solvent
Uncorrected for deformation
Corrected for deformation
R(CH)I WCC)
L( HCH)
R(CH)/ R(CC)
L(HCH)
S,
0.8437(4) 0.8387(4) 0.8402(2) 0.8392(2) 0.8380(l) 0.8361(4) 0.8368(2) 0.8357(4) 0.8355(3) 0.8356(3) 0.8349(3) 0.8345(3) 0.8178(2) 0.8258(l)
117.627(08) 117.756(09) 117.682(05) 117.723(06) 117.993(05) 117.930(10) 117.874(10) 117.911(14) 117.999(08) 117.994(09) 118.127(10) 118.119(09) 118.977(07) 118.663(03)
0.8322(23) 0.8318(23) 0.8339( 13) 0.8316( 14) 0.8311(12) 0.8325(27) 0.8314(21) 0.8316(31) 0.8342(20) 0.8326( 20) 0.8315(23) 0.8329(21) 0.8319(15) 0.8311(24)
118.05(09) 118.00(09) 117.91(05) 118.00(05) 118.23(05) 118.04(10) 118.07(08) 118.05(12) 118.02(07) 118.08(08) 118.22(08) 118.15(08) 118.39(05) 118.40(09)
0.17849 0.19174 0.08836 0.10020 0.10236 0.15424 0.11930 0.08825 0.17153 0.16232 0.10619 0.13255 0.05903 0.07978
Combined analysis corrected for deformation
0.8315(14)
118.12(05)
Infrared spectroscopy [ 7 ] Electron diffraction [ 81
0.8309(10) 0.8247(12)
118.17(17) 118.4(l)
ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 ZLI 1167/EBBA ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
337
-4
-3
-2
-1
0
1
2 cl3 CH
A*c,
3 4
1
4
5
C1O-22 Jl
Fig. 2. Solvent effects on the bond distance ratio R(CH)/R(CC) in allene determined in the different solvents without (m) and with (0) correlation corrections as a function of the CH bond anisotropy of methane in the same solvent, solvent independent value from the combined analysis (l), infrared spectroscopy (2) and electron diffraction (3) results.
117.5j -4
I -3
I -2
I -1
I 0
I 1
“*w
I 2
(%H4)
I 3
I 4
I 5
C1O-22 Jl
Fig. 3. Solvent effect on the HCH bond angle in allene determined in the different solvents without (m) and with (0) correlation corrections as a function of the CH bond anisotropy of methane in the same solvent, solvent independent value from the combined analysis (l), infrared spectroscopy (2) and electron diffraction (3) results.
7
6
::-0, -4 -4
-3
-2
I -1
I 0
I 1 **c,
I 2
I 3
cl3 CH,)
I 4 [IO-** Jl
Fig. 4. Interdependence between the anisotropies of the CH bond interaction tensors of allene and methane in the different solvents.
The considerable solvent effects on the structure are reduced greatly by the correction for correlated deformation. Almost all the results agree within the errors with the IR data. Finally, the fit of the combined data gives results with reduced errors, in excellent agreement with IR but in disagreement with ED results.
TABLE 5 Anisotropies of the interaction parameters in 103’ X J of the allene CC and CH bonds and the CH bond of methane dissolved in the same solvents Liquid crystal
AA (C=c)
ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 ZLI 1167/EBBA ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
l&33(19) 19.24(19) 9.29(11) 10.42(10) 10.29(11) 15.29( 16) 12.07(12) 9.00(09) 16.77(17) 15.92(16) 10.46( 11) 12.93(13) 5.24(07) 7.37(09)
AA (C-H) 5.84(76) 4.46(79) 2.49(42) 2.56(42) 0.98(43) 1.90(67) 1.90(50) 1.17(38) 1.39(70) 1.38(67) 0.06(44) 0.11(55) -3.40(26) -2.79( 34)
AA (Methane) 4.19(09) 2.07(U)
1.06(01)
1.06(16) 0.52(11) 0.32( 09) -0.01(12) --0.07(08) --0.32( 14) -0.38(13) -0.73(08) -1.09(11) -3.60(11) -3.78(11)
339
CONCLUSIONS
The large scatter of structure results (r(CH)/r(CC) between 0.818 and 0.844, L(HCH) between 117.63” and 118.98”) obtained from direct couplings which have not been corrected for correlated deformation again confirms that generally the corrections must be performed. The fact that the structures derived from corrected data for 14 different solvents agree with each other and with IR data is excellent confirmation of the theory which attributes the solvent effects to correlated molecular deformation. The linear relationship between the anisotropies of the CH bond interaction tensors of allene and of methane indicate that similar interactions (probably van der Waals [lo] ) must be acting in both molecules. REFERENCES 1 2 3 4 5 6 7 8
M. Kellerhals, P. Diehl, J. Lounila and R. Wasser, J. Mol. Struct., 156 (1987) 255. S. Sfrkora, J. Vogt, H. Bosiger and P. Diehl, J. Magn. Reson., 36 (1979) 53. N. J. Koole and M. J. A. de Bie, J. Magn. Reson., 23 (1976) 9. P. Diehl, H. P. Kellerhals and W. Niederberger, J. Magn. Reson., 4 (1971) 352. F. Hegelund, J. L. Duncan and D. C. McKean, J. Mol. Spectrosc., 65 (1977) 366. P. Diehl, P. M. Henrichs and W. Niederberger, Mol. Phys., 20 (1971) 139. A. G. Maki and R. A. Toth, J. Mol. Spectrosc., 17 (1959) 136. A. Almenningen, 0. Bastiansen and M. Traetteberg, Acta Chem. Stand., 13 (1959) 1699. 9 J. Jokisaari and Y. Hiltunen, Mol. Phys., 50 (1983) 1013. 10 P. Lounila, Mol. Phys., 58 (1986) 897.
Journal
THE r, STRUCTURE OF ALLENE: A STUDY IN NMR OF ORIENTED MOLECULES
P. DIEHL, C. BARALDI, Department (Switzerland)
M. KELLERHALS
of Physics, University
in The Netherlands
OF SOLVENT
EFFECTS
and R. WASSER
of Base& Klingelbergstrasse
82, CH 4056
Base1
(Received 15 June 1987)
ABSTRACT NMR spectra of partially oriented allene in 14 different liquid crystal solvents have been analyzed. The resulting direct couplings corrected for harmonic vibrations were used to determine the restructures. Considerable solvent effects were detected which disappeared, if the data were corrected also for the correlated molecular deformation. A solvent independent restructure which agreed well with IR results, and the interaction parameters of the CH and CC bonds of allene for all the solvents were determined. INTRODUCTION
The forces which orient molecules dissolved in liquid crystals also deform the solute in a correlated way, i.e. the solute structure slightly depends upon the molecular orientation with respect to the liquid crystal director. This correlated deformation contributes to the observed direct couplings and causes a solvent dependence of the molecular structure [l] . Therefore the direct couplings must be corrected not only for harmonic vibrations [2] but also for the deformation. For the corrections the interactions between the liquid crystal and the solute are assumed to be additive segmental interaction tensors corresponding to torques acting on the individual bonds of the solute. The deformation contribution to the coupling depends upon the molecular force constants and the derivatives of the interaction tensors as well as of the direct couplings with respect to the normal coordinates. Obviously these contributions are rather complex and must be calculated by computer. In the interpretation of the observed direct couplings in terms of molecular structure and orientation the bond interaction tensors are introduced as unknown parameters. They are fitted iteratively together with the nuclear coordinates. This increase in the number of unknown parameters can usually be compensated by the use of data combined from several solvents. In this study of allene the five observed direct couplings over-determine the problem. There are two unknown structure parameters and two unknown bond interaction tensor anisotropies (AA) in each liquid crystal. Consequently the solvent effects can be determined separately for each solvent as well as for a combination of solvents. We have studied 14 different 0022-2860/87/$03.50
0 1987 Elsevier Science Publishers B.V.
334
solvents so that 70 direct couplings are available for the determination of two structure parameters and 28 bond interaction tensor anisotropies. A comparison of the results for the individual solvents provides an excellent test of the solvent effect theory. EXPERIMENTAL
Commercially available allene was dissolved in the degassed liquid crystals to which 13C-methane had been added as a reference. The solvents as well as the solute concentrations and the 13C-methane (CH) couplings are summarized in Table 1. Phase 4 and all the ZLI liquid crystals were obtained from Merck, E48 from BDH, HAB and EBBA from Roche. Indirect couplings were taken from the literature [ 31 . The ‘H spectra with ‘3C-satellites were recorded on a Bruker WH-90 DS FT-spectrometer at 90 MHz and analyzed with the computer program LEQUOR [ 41. The resulting direct couplings are summarized in Table 2. For the numbering of nuclei see Fig. 1. Corrections for harmonic vibrations based on a force field from the literature [5] were applied to the direct couplings measured. The percentage harmonic corrections are shown in Table 3. From these couplings the molecular r, structures were determined with the program SHAPE [6]. The direct couplings were then corrected for the correlated deformation and the resulting structures were calculated for the individual solvents. For the analysis the experimental errors of the direct couplings were increased by 0.5 Hz in order to take into account the approximations introduced by the theory of correlated deformation. Finally, the combined data were interpreted by one solvent independent molecular structure and two interaction tensor anisotropies (for the CH and CC bonds) for each solvent. The results of these three different approaches are summarized in Table 4 and compared with IR [7] and ED [S] data. DISCUSSION
The results of the structure analysis are presented graphically in Figs. 2 and 3 in which the distance-ratios r(CH),/r(CC) and also angles (HCH) are plotted as a function of the interaction tensor anisotropy AA for the CH bond of methane in the same solvent. A comparison of the uncorrected data with the data corrected for correlated deformation shows, that the solvent effects on the allene structure are roughly proportional to those on methane. The smallest allene solvent effects nearly coincide with the zero point of the methane interaction tensor anisotropy, as had been suggested earlier for different molecules [9]. The agreement, which means that CH bending is the dominant correlated deformation in allene, becomes more obvious in a plot of AA for the CH bond of allene (Table 5) versus AA for the CH bond of methane (Fig. 4). Again, as in many other molecules [l] , an excellent linear relationship is observed.
335 TABLE
1
Liquid and
solvents (CH) couplings
used this study, Hz) of
measured
of the ahene (in in same solvent=?
crystal solvent
DD
concentration (mol%) ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 Mixture of ZLI 1167 ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
(66 wt%)/EBBA
W-I)
of methane (Hz) -8.59(18) -4.25(37) -2.18(01) -2.18(32) -1.07(22) -0.65(18) 0.03( 24) 0.15(15) 0.65( 29) 0.77(27) 1.49(17) 2.24(23) 7.38(22) 7.75(23)
13 14 24 17 24 16 3.Ba 19 14 14 15 14 23 12
(34 wt%)
%)
aThe D couplings are converted to values referenced to the director by multiplying D by -2 if the orientation of the director is perpendicular to the applied magnetic field. (ZLI 1167, ZLI 2806 and ZLI 3125). The concentration of allene in E 48 is given in
wt% .
TABLE
2
Experimental
direct
coupling
Liquic crystal solvent
D (1,2)
ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 ZLI 1167/EBBA ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
-780.39(4) 1683.27(8) -387.04(2) 878.77(4) 902.52(4) -679.74(4) 1050.00(4) 777.54(3) 1514.08(6) 1432.58(6) 939.78(3) 1173.00(4) 534.28(4) 715.62(4)
constants
of allene in Hz
D (133)
D (1,5)
143.30(4) -307.30(6) 70.79(2) -160.56(5) -165.51(5) 124.01(3) -191.65(5) -141.72(3) -276.47(5) -251.56(5) -171.88(4) -214.34(5) -96.47(5) -130.16(5)
-184.75(17) 405.45(41) -92.31(07) 210.71(18) 224.22(17) -167.50(17) 256.84(36) 191.12(36) 376.39(30) 355.92(36) 237.46(30) 296.13(30) 149.75(20) 193.25(29)
D (1,6)
200.93(14) -430.59(30) 99.16(06) -225.01(14) -231.72(13) 173.55(13) -268.45(28) -198.50(26) -386.42(22) -365.85(26) -240.33(23) -299.56(21) -134.27(13) -181.59(21)
D (197)
65.23(18) -139.75(39) 32.33(07) -72.94(18) -75.17(17) 56.40(17) -87.14(34) -64.64(36) -125.75(30) -118.79(36) -77.83(30) -97.40(30) -43.69(17) -59.10(29)
336
Fig. 1. Numbering of atoms and definition of the coordinate system of aiiene TABLE 3 Harmonic vibration corrections for the direct coupling constants in ailene calculated from a force-field in the literature [ 5 ] Coupling Correction (W)
D (132) +4.10
D (1,3) -0.15
D (195) +8.31
D (196) +3.02
D (197) +0.11
TABLE 4 Solvent effects on the structure of allene, solvent independent structure from a combined analysis of 14 data-sets and comparison with IR and ED results Liquid crystal solvent
Uncorrected for deformation
Corrected for deformation
R(CH)I WCC)
L( HCH)
R(CH)/ R(CC)
L(HCH)
S,
0.8437(4) 0.8387(4) 0.8402(2) 0.8392(2) 0.8380(l) 0.8361(4) 0.8368(2) 0.8357(4) 0.8355(3) 0.8356(3) 0.8349(3) 0.8345(3) 0.8178(2) 0.8258(l)
117.627(08) 117.756(09) 117.682(05) 117.723(06) 117.993(05) 117.930(10) 117.874(10) 117.911(14) 117.999(08) 117.994(09) 118.127(10) 118.119(09) 118.977(07) 118.663(03)
0.8322(23) 0.8318(23) 0.8339( 13) 0.8316( 14) 0.8311(12) 0.8325(27) 0.8314(21) 0.8316(31) 0.8342(20) 0.8326( 20) 0.8315(23) 0.8329(21) 0.8319(15) 0.8311(24)
118.05(09) 118.00(09) 117.91(05) 118.00(05) 118.23(05) 118.04(10) 118.07(08) 118.05(12) 118.02(07) 118.08(08) 118.22(08) 118.15(08) 118.39(05) 118.40(09)
0.17849 0.19174 0.08836 0.10020 0.10236 0.15424 0.11930 0.08825 0.17153 0.16232 0.10619 0.13255 0.05903 0.07978
Combined analysis corrected for deformation
0.8315(14)
118.12(05)
Infrared spectroscopy [ 7 ] Electron diffraction [ 81
0.8309(10) 0.8247(12)
118.17(17) 118.4(l)
ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 ZLI 1167/EBBA ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
337
-4
-3
-2
-1
0
1
2 cl3 CH
A*c,
3 4
1
4
5
C1O-22 Jl
Fig. 2. Solvent effects on the bond distance ratio R(CH)/R(CC) in allene determined in the different solvents without (m) and with (0) correlation corrections as a function of the CH bond anisotropy of methane in the same solvent, solvent independent value from the combined analysis (l), infrared spectroscopy (2) and electron diffraction (3) results.
117.5j -4
I -3
I -2
I -1
I 0
I 1
“*w
I 2
(%H4)
I 3
I 4
I 5
C1O-22 Jl
Fig. 3. Solvent effect on the HCH bond angle in allene determined in the different solvents without (m) and with (0) correlation corrections as a function of the CH bond anisotropy of methane in the same solvent, solvent independent value from the combined analysis (l), infrared spectroscopy (2) and electron diffraction (3) results.
7
6
::-0, -4 -4
-3
-2
I -1
I 0
I 1 **c,
I 2
I 3
cl3 CH,)
I 4 [IO-** Jl
Fig. 4. Interdependence between the anisotropies of the CH bond interaction tensors of allene and methane in the different solvents.
The considerable solvent effects on the structure are reduced greatly by the correction for correlated deformation. Almost all the results agree within the errors with the IR data. Finally, the fit of the combined data gives results with reduced errors, in excellent agreement with IR but in disagreement with ED results.
TABLE 5 Anisotropies of the interaction parameters in 103’ X J of the allene CC and CH bonds and the CH bond of methane dissolved in the same solvents Liquid crystal
AA (C=c)
ZLI 2806 ZLI 1982 ZLI 1167 ZLI 1132 HAB ZLI 3125 E 48 ZLI 1167/EBBA ZLI 3308 ZLI 2452 ZLI 1275 ZLI 1460 EBBA PHASE 4
l&33(19) 19.24(19) 9.29(11) 10.42(10) 10.29(11) 15.29( 16) 12.07(12) 9.00(09) 16.77(17) 15.92(16) 10.46( 11) 12.93(13) 5.24(07) 7.37(09)
AA (C-H) 5.84(76) 4.46(79) 2.49(42) 2.56(42) 0.98(43) 1.90(67) 1.90(50) 1.17(38) 1.39(70) 1.38(67) 0.06(44) 0.11(55) -3.40(26) -2.79( 34)
AA (Methane) 4.19(09) 2.07(U)
1.06(01)
1.06(16) 0.52(11) 0.32( 09) -0.01(12) --0.07(08) --0.32( 14) -0.38(13) -0.73(08) -1.09(11) -3.60(11) -3.78(11)
339
CONCLUSIONS
The large scatter of structure results (r(CH)/r(CC) between 0.818 and 0.844, L(HCH) between 117.63” and 118.98”) obtained from direct couplings which have not been corrected for correlated deformation again confirms that generally the corrections must be performed. The fact that the structures derived from corrected data for 14 different solvents agree with each other and with IR data is excellent confirmation of the theory which attributes the solvent effects to correlated molecular deformation. The linear relationship between the anisotropies of the CH bond interaction tensors of allene and of methane indicate that similar interactions (probably van der Waals [lo] ) must be acting in both molecules. REFERENCES 1 2 3 4 5 6 7 8
M. Kellerhals, P. Diehl, J. Lounila and R. Wasser, J. Mol. Struct., 156 (1987) 255. S. Sfrkora, J. Vogt, H. Bosiger and P. Diehl, J. Magn. Reson., 36 (1979) 53. N. J. Koole and M. J. A. de Bie, J. Magn. Reson., 23 (1976) 9. P. Diehl, H. P. Kellerhals and W. Niederberger, J. Magn. Reson., 4 (1971) 352. F. Hegelund, J. L. Duncan and D. C. McKean, J. Mol. Spectrosc., 65 (1977) 366. P. Diehl, P. M. Henrichs and W. Niederberger, Mol. Phys., 20 (1971) 139. A. G. Maki and R. A. Toth, J. Mol. Spectrosc., 17 (1959) 136. A. Almenningen, 0. Bastiansen and M. Traetteberg, Acta Chem. Stand., 13 (1959) 1699. 9 J. Jokisaari and Y. Hiltunen, Mol. Phys., 50 (1983) 1013. 10 P. Lounila, Mol. Phys., 58 (1986) 897.