- Email: [email protected]
A semiempirical scf-ci study of steric effects in naphthyl- and phenylphenanthrenes in relation to their electronic spectra
Journal E&tier
of MoIecuZm
Structure Publishing Company, Amsterdam. Printed in the NetherIands
A SEMIJZMPIRICAL SCF-CI NAPHTHYL-
AND
PHENYLPHENANTHRENES
THEIR ELECTRONIC BERNARD
STUDY. OF STERIC EFFECTS
391
IN
IN RELATLON TO
SPECTRA.
TINLAND
Section de .i?e&erchesde iU&anique Ondulatoire Appliquge, FacuItt!des Sciences de Lyon (France)
(Received May 6th, 1968)
SUMMARY
The conformation of I-(1’~naphthyl)-phenanthrene and 2- and I)-phenylphenanthrene have been investigated by means of semiempirical Pariser-Parr-Pople type calculations. The angle of twist between the plane of the phenyl or naphthyl group and the plane of the phenanthrene part of the molecule is predicted on the basis of a comparison with absorption spectra recorded in the liquid phase. The bond lengths have also been computed.
INTRCHXJCTION
The interaction between two n-orbitals is greatest when their axes are parallel. It will decrease if, for steric reasons, there is a twist angle between these axes. Then, spectral properties arise which differ from those expected on the basis of the planar model. The degree of deviation of the observed spectrum from that which would be expected on the basis of a planar model increases with the value of the angle of twist, 8. Accurate calculations of the theoretical spectrum for several values of 8 may therefore permit one to determine the real non-planar geometry of the molecule. A number of such studies have been made of the angle of t&&t in biphenyl ‘-r’. This angIe was found to be 0” in the crystalline phase, W-23” in the liquid phase and 42” in the vapour phase, in good agreement with experimental values. More recently12, a study was made of the angle of twist in l-phenylnaphthalene, 2_phenylnaphthalene, 9, IO-diphenylanthracene, I ,2’-dinaphthyl and 2,2’dinaphthyl, all in the liquid phase. For these molecules, the values of 8 estimated from the w absorption spectra are 46” 1S, 34O W, 60”, 0” and 0” respectively. The- hydrocarbon ~moleculesconsidered in this paper are: 2-phenylphenak threne, 9-phenylphenantbrene and I-(1-‘-naphthyl)-phenanthrene, all in the liquid. phase; J. i Mol.
Structure, 2 (1968) 391-396
B. TzINLAND
392 METHOD.AND
PARAMETERS
The SCF~MO-CI formalism of the Pariser-Parr-Pople method’ 3 - ls has been tised with.the variable-/3 approximation of Nishiioto and For$ter16*“. All molecules were assigned regular structures with equal atom-atom .bond lengths (1.4 A) around, the rings.and,all bond angles set equal to 120”. The twisted bond was assumed to he of constant length (1.5 A) as in the case of crystalline biphenylr8 for all values of the angle of twist 8. The two-center core integrals, the bond lengths (except the twisted bond that was kept equal to 1.5 A) and the two-center repulsion integrals between neighbouring atoms were adjusted at every iteration by means of the relations: B,rv= B,, .= Bpv = rJ&v =
-0.51&-2.04 -0.51 ppv- 1.90 -0.51 pIIv- 1.84 -0.18 prcv+ 1.517
for the phenyl groups for the naphthyl group for the phenanthrene group in all cases
YPV= 14.397/(a,, + r&
(ref. 19)
The semiempirical parameters used were: 1, = 11.16 eV and y, = 11.13 eV. In the.determination of the value of fi for the twisted bond, use was made of the approximate proportionality of /3 and the z-z overlap integral S2”. Thus, the value of /? for the benzene ring bonds was reduced by the factor”: S,_,/S,_, = 0.859. For 0 = 0”: BtWisted = -2.39 x 0.859 = -2.05 eV. For 0 > O”, we admitted the validity of the relation”: B*wisted = -2.05 x cos
8.
RESULTS
The computed and experimental electronic singlet transition energies and oscillator strengths of the absorption spectra in the liquid phase of the molecules studied are summarized in Tables 1-4. The experimental values of the oscillator strengthsfwere estimated from the absorption curves by means of the usual relation22: j- = 4.32 x lo-’
x smaxx A.5
where Avis the band width (in cm-‘) at half-maximum extinction. It may be seen from Table 1 that the variable-p method used gives fairly good results for the spectrum of phenanthrene. The values of 8 which give the best accordance between the experimental and computed spectra are .clearly 45” for 2-phenylphenanthrene and. 60” for 9-phenylphenanthrene. In ‘the case of I-(1’-naphthyl)-phenanthrene, it appears JSMOT, ‘Siiucture,2
(1968) 3911396.
STERIC TABLE
EFFECTS
IN NAPHTHYL-
AND PHENYLPHENANTHRENES
393
1 (eV)moscm+moti
~m~~~TraG4smoNEpjeRG~
co&. AE
expt. Akl;
3.682 4.199 4.629 4.920 5.042 5.308 5.506 5.872 6.032 6.093 6.157 6.652 6.756 6.768 7.385
SXRENG-R~SF~RP~NANTHRENX~
cak. f
tipi. f
0. 0.32 0. 1.54 0.59 0, 0.35 0. 0.15 0.29 0. 0.46 0.22 0. I.01
4.22 4.93 5.05 5.57
0.06 0.87 0.67 0.15
TABLE 2 ELECTRONICSPECXRUhfOF~-PHENYLPHENANTHRENE 8 = 0"
8 =
8 = 30”
15”
Ekpr. data2f
e = 45”
AE
f
AE
f
AE
f
AE
f
3.769 4.185 4.416 4.898 4.916 5.432 5.437 5.807 5.886 6.072 6.292 6.315 6.632 7.085
0.
3.776 4.194 4.438 4.917 4.929 5.453 5.452 5.818 5.909 6.088 6.294 6.319 6.625 7.097
0. 0. 2.42 0. 0.8 0. 0.05 0.04 0. 0.42 0. 0.17 0.29 0.3
3.794 4.213 4.511 4.972 4.964 5.515 5.500 5.853 5.978 6.133 6.297 6.331 6.607 7.085
0.
0.05 2.36 0. 0.86 0. 0.03 0.03 0. 0.37 0. 0.17 0.31 0.3
3.818 4.227 4.633 5.051 5.013 5.626 5.594 5.916 6.086 6.201 6.298 6.350 6.582 7.183
0.17 2.21 0. 0.92 0. 0. 0.01 0. 0.25 0. 0.21 0.32 0.29
0.01 2.41 iii3 0. 0.05 0.05 iii4 0. 0.18 0.29 0.3
AE
f
4.24 4.63
0.3 1 1.94
0.
from Table 4 that a value of 6 between 60” and 70” would be satisfactory. Unfortunately, there is no experimenta information available at present for comparison with these rest&s. The computed bond lengths of ah the molecules under consideration are listed in Table 5 according to the numbering scheme of Fig. 1. There is also a lack of experimental values for these interatomic distances. The calculations were performed on a CDC 3600 computer, -using a modified version of the original SCF MO CX program written in Fortran IV bv Bloor and Gilson and distributed by the QCPE organizationz3. J. Mol. Structure, 2 (1968) 391-396
B.-:TINLAND
394 TABLE 3 ELJXiXONIC
SPECTRUM
.e =
t3=0”
OF %PHENYLPHENANTHRFiNE
15”
e.=
30”
AE
f
AE
f
AE
f
AE
3.768 3.895 4.788 4.846 4.932 5.100 5.108 5.495 5.676 6.082 6.321 6.445 6.504 6.596 6.780 7.002
0.
3.773 3.916 4.806 4.853 4.959 5.115 5.129 5.513 5.687 6.088 6.312 6.447
0.
3.789 3.975 4.857 4.872 5.041 5.164 5.191 5.569 5.719 6.108 6.280 6.451 6.504 6.582 6.814 7.017
0.
0.67 1.13 1.07 .O. 0.2 0. 0. 0.29 0.32 0. 0.04 0.13 0. 0.78 0.59
3.809 4.058 4.935 4.896 5.170 5.252 5.288 5.665 5.766 6.143 6.215 6.454 6.505 6.566 6.864 7.035
TABLE
4
ELECTRONIC
e=
6.504 6.592 6.788 7.006
SPECTRUM
0.65 1.15 1.11 0. 0.18 0. 0. 0.27 0.32 0. 0.04 0.12 0. 0.75 0.6
0.59 1.19 I.22 0. 0.14 0. 0. 0.21 0.3 0. 0.03 0.09 0. 0.8 0.62
f 0.
0.5 1.21 1.36 0. 0.12 0. 0. 0.14 0.26 0. 0.03 0.06 0. 0.8 0.67
AE. 3.827 4.141 5.021 4.921 5.328 5.390 5.413 5.810 5.816 6.197 6.094 6.449 6.507 6.548 6.941 7.059
Expt. &taz4
f 0.. 0.42 1.19 1.50 0. 0.14 0. 0. 0.06 0.2 0. 0.03 0.04 0. 0.8 0.75
AE
f
4.16 5.05 4.87
0.19 1.04 0.6
OF l-(I’-NAPHTHYL)-PHENANTHRENE
8 = 15O
0”
e=600
8 = 45”
8 = 30”
e = 450
8 = 60”
Expt. data24
AE
f
AE
f
AE
f
AE
f
AE
f
AE
f
3.560 3.741 3.973 4.272 4.644 4.698 4.903 5.240 5.251 5.438 5.658 5.837 6.047 6.171 6.272 6.329
0.95
3.591 3.749 3.980 4.280 4.662 4.714 4.906 5.252 5.261 5.431 5.645 5.834 6.040 6.169 6.271 6.324
0.94 0. 0. 0.17 0. 0.61 0.5 1.51 0. 0.55 0.4 0. 0.48 0.8 0. 0.15
3.683 3.770 3.997 4.305 4.713 4.758 4.916 5.284 5.289 5.411 5.609 5.823 6.015 6.166 6.270 6.312
0.89 0.
3.828 3.798 4.020 4.340 4.786 4.822 4.932 5.294 5.331 5.410 5.555 5.809 5.971 6.162 6.267 6.295
0.81 0. 0. 0.17 0. 0.98 0.45 0.9 0. 1.03 0.39 0. 0.55 0.68 0. 0.08
4.002 3.824 4.040 4.384 4.861 4.889 4.950 5.226 5.376 5.473 5.496 5.794 5.904 6.159 6.263 6.277
0.7 0. 0. 0.19 0. 1.28 0.37 0.66 0. 1.19 0.45 0. 0.51 0.65 .O. 0.04
4.11
0.2
4.45
0.26
4.86
0.88
0.
0. 0.17 0. 0.56 0.51 1.53 0. c.55 0.4 0. 0.46 0.8 0. 0.16
J. Mol. Structure, 2 (1968) 391-396
0. 0.17 0. 0.75 0.49 1.40 0. 0.59 0.41 0. 0.52 0.73 0. 0.12
STERIC.EFFECTS’IN
2
1 2 3 4 :
3 4 11 13
6 7 8 9 9 10
! 8 I4 14 io 12
I
12
II 1t 13 1 2
12 13 14 15 15
1: I6 27 18 19 15 18 19 20 21 22 15 23
15 16 $7 18 19 20 20 23 23 21 22 24 24 24
NAPHTWYL-
1.386 1.409 E.387 1.413
X.367 1.438 1.415 1.410 1.443
AND
PHENYLPHB-NANTHRENES
1389 1.411 1.386 1.414 1.387 1.413
i-386 1.409 1.387 1.413 1.413 1.38?-
1.388 1.408 1.387, 1.413 1.387 1.413
1.401, I.386 1.415 1.438 1.367 1,438 1.414 1.4LO 1.443 XAIO
1.4Q!J 1.386 1.414 1.439 1.369 1.437 1.415 1.410 1.443 1.410
1*4O!J 1.386 1.415 1.438. 1.368 1.437 1.416 1.410 I.443 1.410 1.500
1.500 1.399 1.397 1.397 1.397 1.397 1.399
f.382 X.415 1.380
x.500 1.400 I.396 1.397 1.397 1.396. 1.400
1.380 1.423 1.423 1.416 1.380 1.422 1.424 1.4ts
f- fl’-nophthyl) - phenanthrene
7
395
B_ TINLAND
396 REFERENCES
1 G. H. BEAVEN, Steric e@cts in conjugated systems, Butterworths, London, 1958, p. 22. 2 A. GOLEBD%VSKI AND A. PARCZEWSKI,Theor. Chim. Acta, 7 (1967) 171. 3 Y. GONDO,J. Chem. Phys., 41 (1964) 3928. 4 R. GRINIER, Mol. Phys., 11 (1966) 197. 5 K. IGUCHI, J. Phys. Sot. Japan, 12 (19!7) 1250. 6 A. LONDON, L Chem. Phys., 13 (1945) 396. 7 J. N. M~RRELL, J. Chem. Sot., (1956),3779. 8 J_ N. M URRELL AND H. C. LONGUET-HIGGINS, Proc. Phys. Sac. London, 9 i.
T. STEWART, J. Chem. Sot.,
(1958) 4016.
A 68 (1960) 601.
10 H. SUZUKI, EIectronic absorption spectra and geometry of organic molecules, Academic Press, New York, 1967, p. 261. 11 B. TINLAND, Acta PhyS. Hung., in press. 12 B. TINLAND, Theor. Chim. Acta, in press. 13 R PARISER AND R. G. PARR, J. Chem. Phys, 21 (1953) 466, 767. 14 R. PARISER,J. Chem. Phys., 24 (1956) 250. 15 J. A. POPLE, Trans. Faraday Sot., .49 (1953) 1375. 16 K. NISHIMOTO AND L. S. FORSIER, Theor. Chim. Acta, 3 (1965) 407. 17 K. NISHIMOTO AND L. S. FORS~R, Theor. Chim. Acta, 4 (1966) 155. 18 Tables of interatomic distances and configuration in molecules and ions, The Chemical Society, London, 1958. 19 K. NISHIMOTO AND N. MATAGA; Z. Physik. Chem. Frankfurt, 12 (1957) 335. 20 8. S. MULLIKEN, C. A. RIEKE AND W. G. BROW, J. Am. Chem. Sot., 63 (1941) 41. 21 R. S. M~LLIKEN, C. A. RIEICE, D. ORLOFF AND H. ORLOFI=, J. Am. Chem. Sot., 17 (1949) 1248. 22 C. SANDOFGY,Efectronic spectra and quantum chemistry, Prentice Hall, Englewood Cliffs, 1964, p-103. 23 Quantum Chemisty Program Exchange, Chemistry Department, Indiana University, Bloomington, Ind. 24 R. A. FRIEDEL AND M. ORCHIN, Ubraviolet spectra of aromatic compounds, Wiley, London, 1951. J. Mol. Structure, 2 (1968) 391-396
of MoIecuZm
Structure Publishing Company, Amsterdam. Printed in the NetherIands
A SEMIJZMPIRICAL SCF-CI NAPHTHYL-
AND
PHENYLPHENANTHRENES
THEIR ELECTRONIC BERNARD
STUDY. OF STERIC EFFECTS
391
IN
IN RELATLON TO
SPECTRA.
TINLAND
Section de .i?e&erchesde iU&anique Ondulatoire Appliquge, FacuItt!des Sciences de Lyon (France)
(Received May 6th, 1968)
SUMMARY
The conformation of I-(1’~naphthyl)-phenanthrene and 2- and I)-phenylphenanthrene have been investigated by means of semiempirical Pariser-Parr-Pople type calculations. The angle of twist between the plane of the phenyl or naphthyl group and the plane of the phenanthrene part of the molecule is predicted on the basis of a comparison with absorption spectra recorded in the liquid phase. The bond lengths have also been computed.
INTRCHXJCTION
The interaction between two n-orbitals is greatest when their axes are parallel. It will decrease if, for steric reasons, there is a twist angle between these axes. Then, spectral properties arise which differ from those expected on the basis of the planar model. The degree of deviation of the observed spectrum from that which would be expected on the basis of a planar model increases with the value of the angle of twist, 8. Accurate calculations of the theoretical spectrum for several values of 8 may therefore permit one to determine the real non-planar geometry of the molecule. A number of such studies have been made of the angle of t&&t in biphenyl ‘-r’. This angIe was found to be 0” in the crystalline phase, W-23” in the liquid phase and 42” in the vapour phase, in good agreement with experimental values. More recently12, a study was made of the angle of twist in l-phenylnaphthalene, 2_phenylnaphthalene, 9, IO-diphenylanthracene, I ,2’-dinaphthyl and 2,2’dinaphthyl, all in the liquid phase. For these molecules, the values of 8 estimated from the w absorption spectra are 46” 1S, 34O W, 60”, 0” and 0” respectively. The- hydrocarbon ~moleculesconsidered in this paper are: 2-phenylphenak threne, 9-phenylphenantbrene and I-(1-‘-naphthyl)-phenanthrene, all in the liquid. phase; J. i Mol.
Structure, 2 (1968) 391-396
B. TzINLAND
392 METHOD.AND
PARAMETERS
The SCF~MO-CI formalism of the Pariser-Parr-Pople method’ 3 - ls has been tised with.the variable-/3 approximation of Nishiioto and For$ter16*“. All molecules were assigned regular structures with equal atom-atom .bond lengths (1.4 A) around, the rings.and,all bond angles set equal to 120”. The twisted bond was assumed to he of constant length (1.5 A) as in the case of crystalline biphenylr8 for all values of the angle of twist 8. The two-center core integrals, the bond lengths (except the twisted bond that was kept equal to 1.5 A) and the two-center repulsion integrals between neighbouring atoms were adjusted at every iteration by means of the relations: B,rv= B,, .= Bpv = rJ&v =
-0.51&-2.04 -0.51 ppv- 1.90 -0.51 pIIv- 1.84 -0.18 prcv+ 1.517
for the phenyl groups for the naphthyl group for the phenanthrene group in all cases
YPV= 14.397/(a,, + r&
(ref. 19)
The semiempirical parameters used were: 1, = 11.16 eV and y, = 11.13 eV. In the.determination of the value of fi for the twisted bond, use was made of the approximate proportionality of /3 and the z-z overlap integral S2”. Thus, the value of /? for the benzene ring bonds was reduced by the factor”: S,_,/S,_, = 0.859. For 0 = 0”: BtWisted = -2.39 x 0.859 = -2.05 eV. For 0 > O”, we admitted the validity of the relation”: B*wisted = -2.05 x cos
8.
RESULTS
The computed and experimental electronic singlet transition energies and oscillator strengths of the absorption spectra in the liquid phase of the molecules studied are summarized in Tables 1-4. The experimental values of the oscillator strengthsfwere estimated from the absorption curves by means of the usual relation22: j- = 4.32 x lo-’
x smaxx A.5
where Avis the band width (in cm-‘) at half-maximum extinction. It may be seen from Table 1 that the variable-p method used gives fairly good results for the spectrum of phenanthrene. The values of 8 which give the best accordance between the experimental and computed spectra are .clearly 45” for 2-phenylphenanthrene and. 60” for 9-phenylphenanthrene. In ‘the case of I-(1’-naphthyl)-phenanthrene, it appears JSMOT, ‘Siiucture,2
(1968) 3911396.
STERIC TABLE
EFFECTS
IN NAPHTHYL-
AND PHENYLPHENANTHRENES
393
1 (eV)moscm+moti
~m~~~TraG4smoNEpjeRG~
co&. AE
expt. Akl;
3.682 4.199 4.629 4.920 5.042 5.308 5.506 5.872 6.032 6.093 6.157 6.652 6.756 6.768 7.385
SXRENG-R~SF~RP~NANTHRENX~
cak. f
tipi. f
0. 0.32 0. 1.54 0.59 0, 0.35 0. 0.15 0.29 0. 0.46 0.22 0. I.01
4.22 4.93 5.05 5.57
0.06 0.87 0.67 0.15
TABLE 2 ELECTRONICSPECXRUhfOF~-PHENYLPHENANTHRENE 8 = 0"
8 =
8 = 30”
15”
Ekpr. data2f
e = 45”
AE
f
AE
f
AE
f
AE
f
3.769 4.185 4.416 4.898 4.916 5.432 5.437 5.807 5.886 6.072 6.292 6.315 6.632 7.085
0.
3.776 4.194 4.438 4.917 4.929 5.453 5.452 5.818 5.909 6.088 6.294 6.319 6.625 7.097
0. 0. 2.42 0. 0.8 0. 0.05 0.04 0. 0.42 0. 0.17 0.29 0.3
3.794 4.213 4.511 4.972 4.964 5.515 5.500 5.853 5.978 6.133 6.297 6.331 6.607 7.085
0.
0.05 2.36 0. 0.86 0. 0.03 0.03 0. 0.37 0. 0.17 0.31 0.3
3.818 4.227 4.633 5.051 5.013 5.626 5.594 5.916 6.086 6.201 6.298 6.350 6.582 7.183
0.17 2.21 0. 0.92 0. 0. 0.01 0. 0.25 0. 0.21 0.32 0.29
0.01 2.41 iii3 0. 0.05 0.05 iii4 0. 0.18 0.29 0.3
AE
f
4.24 4.63
0.3 1 1.94
0.
from Table 4 that a value of 6 between 60” and 70” would be satisfactory. Unfortunately, there is no experimenta information available at present for comparison with these rest&s. The computed bond lengths of ah the molecules under consideration are listed in Table 5 according to the numbering scheme of Fig. 1. There is also a lack of experimental values for these interatomic distances. The calculations were performed on a CDC 3600 computer, -using a modified version of the original SCF MO CX program written in Fortran IV bv Bloor and Gilson and distributed by the QCPE organizationz3. J. Mol. Structure, 2 (1968) 391-396
B.-:TINLAND
394 TABLE 3 ELJXiXONIC
SPECTRUM
.e =
t3=0”
OF %PHENYLPHENANTHRFiNE
15”
e.=
30”
AE
f
AE
f
AE
f
AE
3.768 3.895 4.788 4.846 4.932 5.100 5.108 5.495 5.676 6.082 6.321 6.445 6.504 6.596 6.780 7.002
0.
3.773 3.916 4.806 4.853 4.959 5.115 5.129 5.513 5.687 6.088 6.312 6.447
0.
3.789 3.975 4.857 4.872 5.041 5.164 5.191 5.569 5.719 6.108 6.280 6.451 6.504 6.582 6.814 7.017
0.
0.67 1.13 1.07 .O. 0.2 0. 0. 0.29 0.32 0. 0.04 0.13 0. 0.78 0.59
3.809 4.058 4.935 4.896 5.170 5.252 5.288 5.665 5.766 6.143 6.215 6.454 6.505 6.566 6.864 7.035
TABLE
4
ELECTRONIC
e=
6.504 6.592 6.788 7.006
SPECTRUM
0.65 1.15 1.11 0. 0.18 0. 0. 0.27 0.32 0. 0.04 0.12 0. 0.75 0.6
0.59 1.19 I.22 0. 0.14 0. 0. 0.21 0.3 0. 0.03 0.09 0. 0.8 0.62
f 0.
0.5 1.21 1.36 0. 0.12 0. 0. 0.14 0.26 0. 0.03 0.06 0. 0.8 0.67
AE. 3.827 4.141 5.021 4.921 5.328 5.390 5.413 5.810 5.816 6.197 6.094 6.449 6.507 6.548 6.941 7.059
Expt. &taz4
f 0.. 0.42 1.19 1.50 0. 0.14 0. 0. 0.06 0.2 0. 0.03 0.04 0. 0.8 0.75
AE
f
4.16 5.05 4.87
0.19 1.04 0.6
OF l-(I’-NAPHTHYL)-PHENANTHRENE
8 = 15O
0”
e=600
8 = 45”
8 = 30”
e = 450
8 = 60”
Expt. data24
AE
f
AE
f
AE
f
AE
f
AE
f
AE
f
3.560 3.741 3.973 4.272 4.644 4.698 4.903 5.240 5.251 5.438 5.658 5.837 6.047 6.171 6.272 6.329
0.95
3.591 3.749 3.980 4.280 4.662 4.714 4.906 5.252 5.261 5.431 5.645 5.834 6.040 6.169 6.271 6.324
0.94 0. 0. 0.17 0. 0.61 0.5 1.51 0. 0.55 0.4 0. 0.48 0.8 0. 0.15
3.683 3.770 3.997 4.305 4.713 4.758 4.916 5.284 5.289 5.411 5.609 5.823 6.015 6.166 6.270 6.312
0.89 0.
3.828 3.798 4.020 4.340 4.786 4.822 4.932 5.294 5.331 5.410 5.555 5.809 5.971 6.162 6.267 6.295
0.81 0. 0. 0.17 0. 0.98 0.45 0.9 0. 1.03 0.39 0. 0.55 0.68 0. 0.08
4.002 3.824 4.040 4.384 4.861 4.889 4.950 5.226 5.376 5.473 5.496 5.794 5.904 6.159 6.263 6.277
0.7 0. 0. 0.19 0. 1.28 0.37 0.66 0. 1.19 0.45 0. 0.51 0.65 .O. 0.04
4.11
0.2
4.45
0.26
4.86
0.88
0.
0. 0.17 0. 0.56 0.51 1.53 0. c.55 0.4 0. 0.46 0.8 0. 0.16
J. Mol. Structure, 2 (1968) 391-396
0. 0.17 0. 0.75 0.49 1.40 0. 0.59 0.41 0. 0.52 0.73 0. 0.12
STERIC.EFFECTS’IN
2
1 2 3 4 :
3 4 11 13
6 7 8 9 9 10
! 8 I4 14 io 12
I
12
II 1t 13 1 2
12 13 14 15 15
1: I6 27 18 19 15 18 19 20 21 22 15 23
15 16 $7 18 19 20 20 23 23 21 22 24 24 24
NAPHTWYL-
1.386 1.409 E.387 1.413
X.367 1.438 1.415 1.410 1.443
AND
PHENYLPHB-NANTHRENES
1389 1.411 1.386 1.414 1.387 1.413
i-386 1.409 1.387 1.413 1.413 1.38?-
1.388 1.408 1.387, 1.413 1.387 1.413
1.401, I.386 1.415 1.438 1.367 1,438 1.414 1.4LO 1.443 XAIO
1.4Q!J 1.386 1.414 1.439 1.369 1.437 1.415 1.410 1.443 1.410
1*4O!J 1.386 1.415 1.438. 1.368 1.437 1.416 1.410 I.443 1.410 1.500
1.500 1.399 1.397 1.397 1.397 1.397 1.399
f.382 X.415 1.380
x.500 1.400 I.396 1.397 1.397 1.396. 1.400
1.380 1.423 1.423 1.416 1.380 1.422 1.424 1.4ts
f- fl’-nophthyl) - phenanthrene
7
395
B_ TINLAND
396 REFERENCES
1 G. H. BEAVEN, Steric e@cts in conjugated systems, Butterworths, London, 1958, p. 22. 2 A. GOLEBD%VSKI AND A. PARCZEWSKI,Theor. Chim. Acta, 7 (1967) 171. 3 Y. GONDO,J. Chem. Phys., 41 (1964) 3928. 4 R. GRINIER, Mol. Phys., 11 (1966) 197. 5 K. IGUCHI, J. Phys. Sot. Japan, 12 (19!7) 1250. 6 A. LONDON, L Chem. Phys., 13 (1945) 396. 7 J. N. M~RRELL, J. Chem. Sot., (1956),3779. 8 J_ N. M URRELL AND H. C. LONGUET-HIGGINS, Proc. Phys. Sac. London, 9 i.
T. STEWART, J. Chem. Sot.,
(1958) 4016.
A 68 (1960) 601.
10 H. SUZUKI, EIectronic absorption spectra and geometry of organic molecules, Academic Press, New York, 1967, p. 261. 11 B. TINLAND, Acta PhyS. Hung., in press. 12 B. TINLAND, Theor. Chim. Acta, in press. 13 R PARISER AND R. G. PARR, J. Chem. Phys, 21 (1953) 466, 767. 14 R. PARISER,J. Chem. Phys., 24 (1956) 250. 15 J. A. POPLE, Trans. Faraday Sot., .49 (1953) 1375. 16 K. NISHIMOTO AND L. S. FORSIER, Theor. Chim. Acta, 3 (1965) 407. 17 K. NISHIMOTO AND L. S. FORS~R, Theor. Chim. Acta, 4 (1966) 155. 18 Tables of interatomic distances and configuration in molecules and ions, The Chemical Society, London, 1958. 19 K. NISHIMOTO AND N. MATAGA; Z. Physik. Chem. Frankfurt, 12 (1957) 335. 20 8. S. MULLIKEN, C. A. RIEKE AND W. G. BROW, J. Am. Chem. Sot., 63 (1941) 41. 21 R. S. M~LLIKEN, C. A. RIEICE, D. ORLOFF AND H. ORLOFI=, J. Am. Chem. Sot., 17 (1949) 1248. 22 C. SANDOFGY,Efectronic spectra and quantum chemistry, Prentice Hall, Englewood Cliffs, 1964, p-103. 23 Quantum Chemisty Program Exchange, Chemistry Department, Indiana University, Bloomington, Ind. 24 R. A. FRIEDEL AND M. ORCHIN, Ubraviolet spectra of aromatic compounds, Wiley, London, 1951. J. Mol. Structure, 2 (1968) 391-396