Novel Substituent Effect on 77Se NMR Chemical Shifts Caused by 4c-6e versus 2c-4e and 3c-4e in Naphthalene Peri Positions: Spectroscopic and Theoretical Study

Article abstract of DOI:10.1021/jo9903860

δ(⁸Se) values for 1-[8-(P-YC₆H₄Se)C₁₀H₆]SeSe[C ₁₀H₆(SeC₆H₄Y-p)-8′]-1′ (1: Y = H, OMe, Me, Cl, Br, COOEt, and NO₂) showed a good correlation with those of 1-(MeSe)-8-(p-YC₆H₄Se)C₁₀H₆ (2). While the δ(¹Se) values correlated well with δ(⁸Se) in 2 with a positive proportionality constant of 0.252 (regular correlation), a similar correlation for 1 gave a negative proportionality constant of -0.282 (inverse correlation). To clarify the mechanism associated with the inverse correlation in 1, together with the regular correlation in 2, ab initio MO calculations, containing the GIAO magnetic shielding tensor for the Se nucleus (σ(Se)), were performed on p-YC₆H₄^ASeH- - -^BSeH-^BSeH- - -H^ASeC₆H₄Y-p (3: model of Se₄ 4c-6e for 1) and on p-YC₆H₄^ASeH- - -^BSeH₂ (4 and 5: models of Se₂ π type 2c-4e and ^ASe- - -^BSe-H 3c-4e for 2, respectively) with the 6-311+G(2d,p) basis sets at B3LYP and/or HF levels. The characteristic nature of the substituent effects on atomic charges and δ(Se) values in 3 is demonstrated to be Y^δ-←C₆H₄-Se^δ+- - -Se^δ+-Se^δ+- - -Se^δ+-C₆H₄-Y^δ- and Y^δ-←C₆H₄-Se^down- - -Se^up-Se^up- - -Se^down-C₆H₄-Y^δ-, respectively, (Y = electron-withdrawing) and in 5 is Y^δ-←C₆H₄-Se^δ+- - -Se^δ--H^δ+ and Y^δ-←C₆H₄-Se^down- - -Se^down-H^down, respectively. In the case of 4, a substantial contribution through the naphthylidene group is suggested. These results indicate that the nature of the interaction between the linear four Se atoms in 1 is of the 4c-6e type and that between the two Se atoms in 2 is π type 2c-4e and/or 3c-4e according to the conformations around the Se atoms. The observed NMR parameters are well explained by model calculations on 3-5. Plots of ⁴J(¹Se,⁸Se) versus δ(⁸Se) of 1 and 2 gave good correlations with negative proportionality constants, which indicates that the J values become larger as the electron density on the ⁸Se atoms increases.

Full text of DOI:10.1021/jo9903860

6688
J . Org. Chem. 1999, 64, 6688-6696
Novel Su bstitu en t Effect on 77Se NMR Ch em ica l Sh ifts Ca u sed by
4c-6e ver su s 2c-4e a n d 3c-4e in Na p h th a len e P er i P osition s:
Sp ectr oscop ic a n d Th eor etica l Stu d y
Satoko Hayashi and Waroˆ Nakanishi*
Department of Material Science and Chemistry, Faculty of Systems Engineering, Wakayama University,
930 Sakaedani, Wakayama 640-8510, J apan
Received March 4, 1999
δ(8Se) values for 1-[8-(p-YC6H4Se)C10H6]SeSe[C10H6(SeC6H4Y-p)-8′]-1′ (1: Y ) H, OMe, Me, Cl, Br,
COOEt, and NO2) showed a good correlation with those of 1-(MeSe)-8-(p-YC6H4Se)C10H6 (2). While
the δ(1Se) values correlated well with δ(8Se) in 2 with a positive proportionality constant of 0.252
(regular correlation), a similar correlation for 1 gave a negative proportionality constant of -0.282
(inverse correlation). To clarify the mechanism associated with the inverse correlation in 1, together
with the regular correlation in 2, ab initio MO calculations, containing the GIAO magnetic shielding
tensor for the Se nucleus (σ(Se)), were performed on p-YC6H4ASeH- - -BSeH-BSeH- - -HASeC6H4Y-
p (3: model of Se4 4c-6e for 1) and on p-YC6H4ASeH- - -BSeH2 (4 and 5: models of Se2 π type 2c-4e
and ASe- - -BSe-H 3c-4e for 2, respectively) with the 6-311+G(2d,p) basis sets at B3LYP and/or
HF levels. The characteristic nature of the substituent effects on atomic charges and δ(Se) values
in 3 is demonstrated to be Yδ-rC6H4-Seδ+- - -Seδ+-Seδ+- - -Seδ+-C6H4fYδ- and Yδ-rC6H4-
Sedown- - -Seup-Seup- - -Sedown-C6H4fYδ-, respectively, (Y ) electron-withdrawing) and in 5 is
Yδ-rC6H4-Seδ+- - -Seδ--Hδ+ and Yδ-rC6H4-Sedown- - -Sedown-Hdown, respectively. In the case of
4, a substantial contribution through the naphthylidene group is suggested. These results indicate
that the nature of the interaction between the linear four Se atoms in 1 is of the 4c-6e type and
that between the two Se atoms in 2 is π type 2c-4e and/or 3c-4e according to the conformations
around the Se atoms. The observed NMR parameters are well explained by model calculations on
3-5. Plots of 4J (1Se,8Se) versus δ(8Se) of 1 and 2 gave good correlations with negative proportionality
8
constants, which indicates that the J values become larger as the electron density on the Se atoms
increases.
In tr od u ction
exchange repulsion. The bent structure of 2a must lower
the energy of the filled π- and π*-orbitals of the adduct
as much as possible. The nonbonded interactions in 2a
can be represented by the π-type two-center four-electron
interaction (2c-4e).1 However, we found another type of
structure,2 very recently, in which the n(Se)- - -σ*(Se-
C) 3c-4e interaction is observed in 1-(methylselanyl)-8-
(p-anisylselanyl)naphthalene (2b) and 1-(methylselanyl)-
8-(p-chlorophenylselanyl)naphthalene (2d ). Structures
1a , 2a , and 2d are shown in Chart 1 and the correspond-
ing orbital interactions are outlined in Chart 2, for
convenience of discussion.
In our previous paper,1 we reported the linear align-
ment of the four selenium atoms in bis[8-(phenylselanyl)-
naphthyl] diselenide (1a ), revealed by the X-ray crystal-
lographic analysis. This alignment is the results of an
energy lowering effect due to the construction of the four
center-six electron bond (4c-6e) with four selenium 4p
atomic orbitals as indicated by MO calculations.1 The
character of the charge transfer in the formation of the
4c-6e is that from the p-type lone pairs of the outside
two selenium atoms to the central σ*(Se-Se) orbital. The
Se-Se distance in the diselenide moiety of a model
compound of 1a , H2Se- - -HSe-SeH- - -Se2H, is calculated
to be longer than that calculated for free H2Se2.
Lone pair-lone pair interactions have been demon-
strated to play an important role in the nonbonded spin-
spin couplings between selenium-selenium,3,4 selenium-
fluorine,5 fluorine-fluorine,6 and fluorine-nitrogen7 atoms.
On the other hand, X-ray crystallographic analysis of
1-(methylselanyl)-8-(phenylselanyl)naphthalene
(2a )
4
The values of J (Se,Se) of 1a ,1 2a ,1 1-(acetoxymethylse-
showed that the two Se-C bonds of the methylselanyl
and phenylselanyl groups declined about 50° and 40°,
respectively, from the naphthyl plane.1 The structure 2a
in the vicinity of the Se-C bonds is reproduced by MO
calculations performed on a model compound of 2a , H2-
Se- - -SeH2. The interaction of two p-type lone pairs of
the Se atoms in 2a forms two new π-type molecular
orbitals, which assume an orientation that avoids the
lanyl)-8-(methylselanyl)naphthalene,4b and 1-(methylse-
leninyl)-8-(methylselanyl)naphthalene4b are reported to
be 341.4, 322.4, 310, and 203 Hz, respectively. The values
of 4J (F,Se) and 4J (F,F) in 8-fluoro-1-(p-anisylselanyl)-
(2) Nakanishi, W.; Hayashi, S. Unpublished results.
(3) Nakanishi, W.; Hayashi, S.; Yamaguchi, H. Chem. Lett. 1996,
947.
(4) (a) J ohannsen, I.; Eggert, H. J . Am. Chem. Soc. 1984, 106, 1240.
J ohannsen, I.; Eggert, H.; Gronowitz, S.; Ho¨rnfeldt, A.-B. Chem. Scr.
1987, 27, 359. Fujihara, H.; Mima, H.; Erata, T.; Furukawa, N. J . Am.
Chem. Soc. 1992, 114, 3117. (b) Fujihara, H.; Saito, R.; Yabe, M.;
Furukawa, N. Chem. Lett. 1992, 1437.
(5) Nakanishi, W.; Hayashi, S.; Sakaue, A.; Ono, G.; Kawada, Y. J .
Am. Chem. Soc. 1998, 120, 3635.
* To whom correspondence should be addressed. Tel: +81-734-57-
8252. Fax: +81-734-57-8253 or +81-734-57-8272. E-mail: nakanisi@
sys.wakayama-u.ac.jp.
(1) Nakanishi, W.; Hayashi, S.; Toyota, S. J . Org. Chem. 1998, 63,
8790. See also: Nakanishi, W.; Hayashi, S.; Toyota, S. J . Chem. Soc.,
Chem. Commun. 1996, 371.
10.1021/jo9903860 CCC: $18.00 © 1999 American Chemical Society
Published on Web 08/12/1999

Substituent Effect on 77Se NMR Chemical Shifts
J . Org. Chem., Vol. 64, No. 18, 1999 6689
Ch a r t 1. Str u ctu r es 1a , 2a , a n d 2d
The structure of 2a is very close to that of 1,8-bis-
(methylthio)naphthalene8 and of 1,8-bis(phenyltelluro)-
naphthalene,9 especially in the vicinity of the heteroat-
oms. Influence of the lone pair-lone pair interactions on
the NMR chemical shifts is also of interest.5,10
As an extension of our study, we looked for novel
properties that arose from the 4c-6e-type interaction
constructed by the linearly aligned four Se atoms in 1a .
The properties of the π type 2c-4e in 2a and the linear
3c-4e in 2d were also of interest. It was desirable that
the 77Se NMR chemical shifts were predicted precisely
from theoretical considerations. Magnetic shielding ten-
sors have recently been calculated based on the gauge
including atomic orbital (GIAO) theory for some nuclei
of the first- and second-row elements.11,12 The contribu-
tion of relativistic terms has been pointed out for the
heavier atoms in such calculations;13 however, the con-
tribution to the Se nucleus is expected to be small. The
method is satisfactorily applied on organoselenium com-
pounds14 containing para-substituted phenyl selenides.15
Ab initio MO calculations, containing the GIAO mag-
netic shielding tensor of the selenium nucleus (σ(Se)),
were performed on the model adducts of the diselenides
and the bis-selenides to elucidate the nature of the
nonbonded interactions characteristic of the 4c-6e, 2c-
4e, and 3c-4e types. Here, we would like to present the
results of investigations exhibiting the characteristic
substituent effect on the Se atoms in 4c-6e in 1, in
contrast to that of 2c-4e and/or 3c-4e in 2. The interpre-
tation of the nonbonded interactions in 1a , 2a , and their
derivatives based on the MO calculations is further
examined.
Ch a r t 2. In ter a ction s betw een Lon e P a ir s of Se
Atom s: (a ) Lin ea r 4c-6e Con str u cted by F ou r Se
Atom s, (b) π Typ e Se- - -Se 2c-4e, a n d (c) Lin ea r
Se- - -Se-C 3c-4e
Resu lts a n d Discu ssion
Su bstitu en t Effect on 77Se NMR Ch em ica l Sh ifts
a n d Cou p lin g Con st a n t s. Di[(para-substituted phe-
(8) (a) Glass, R. S.; Andruski, S. W.; Broeker, J . L. Rev. Heteroatom
Chem. 1988, 1, 31. Glass, R. S.; Andruski, S. W.; Broeker, J . L.;
Firouzabadi, H.; Steffen, L. K.; Wilson, G. S. J . Am. Chem. Soc. 1989,
111, 4036. (b) Glass, R. S.; Adamowicz, L.; Broeker, J . L. J . Am. Chem.
Soc. 1991, 113, 1065.
(9) Fujihara, H.; Ishitani, H.; Takaguchi, Y.; Furukawa, N. Chem.
Lett. 1995, 571.
(10) (a) Goldstein, B. M.; Kennedy, S. D.; Hennen, W. J . J . Am.
Chem. Soc. 1990, 112, 8265. (b) Barton, D. H. R.; Hall, M. B.; Lin, Z.;
Parekh, S. I.; Reibenspies, J . J . Am. Chem. Soc. 1993, 115, 5056.
(11) Cheeseman, J . R.; Trucks, G. W.; Keith, T. A.; Frisch, M. J . J .
Chem. Phys. 1996, 104, 5497.
(12) (a) Forsyth, D. A.; Sebag, A. B. J . Am. Chem. Soc. 1997, 119,
9483. (b) Olah, G. A.; Shamma, T.; Burrichter, A.; Rasul, G.; Prakash,
G. K. S. J . Am. Chem. Soc. 1997, 119, 12923; Olah, G. A.; Shamma,
T.; Burrichter, A.; Rasul, G.; Hachoumy, M.; Prakash, G. K. S. J . Am.
Chem. Soc. 1997, 119, 12929.
(13) Tanaka, S.; Sugimoto, M.; Takashima, H.; Hada, M.; Nakatuji,
H. Bull. Chem. Soc., J pn. 1966, 69, 953. Ballard, C. C.; Hada, M.;
Kaneko, H.; Nakastuji, H. Chem. Phys. Lett. 1996, 254, 170. Nakastuji,
H.; Hada, M.; Kaneko, H.; Nakajima, T. Chem. Phys. Lett. 1996, 255,
429. Hada, M.; Kaneko, H.; Nakastuji, H. Chem. Phys. Lett. 1996, 261,
7. Nakastuji, H.; Hu, Z.-M.; Nakajima, T. Chem. Phys. Lett. 1997, 275,
429. See also references cited therein.
(14) (a) Nakatsuji, H.; Higashioji, T.; Sugimoto, M. Bull. Chem. Soc.
J pn. 1993, 66, 3235. (b) Magyarfalvi, G.; Pulay, P. Chem. Phys. Lett.
1994, 225, 280. (c) Bu¨hl, M.; Gauss, J .; Stanton, J . F. Chem. Phys.
Lett. 1995, 241, 248. (d) Bu¨hl, M.; Thiel, W.; Fleischer, U.; Kutzelnigg,
W. J . Phys. Chem. 1995, 99, 4000. (e) Malkin, V. G.; Malkina, O. L.;
Casida, M. E.; Salahub, D. R. J . Am. Chem. Soc. 1994, 116, 5898. (f)
Schreckenbach, G.; Ruiz-Morales, Y.; Ziegler, T. J . Chem. Phys. 1996,
104, 8605. (g) Ellis, P. D.; Odom, J . D.; Lipton, A. S.; Chen, Q.; Gulick,
J . M. In Nuclear Magnetic Shieldings and Molecular Structure; Tossel,
J . A., Ed.; NATO ASI Series; Kluwer Academic Publishers: Dordrecht,
1993; p 539. See also references cited therein.
naphthalene,5 8-fluoro-1-(methylselanyl)naphthalene,5 and
1,8-difluoronaphthalene6b are observed to be 285.0, 276.7,
and 58.8 Hz, respectively. Orientation of the lone pairs
at the Se atoms and/or electron densities of the orbitals
must play an important role in determining the J values.
(6) (a) Mallory, F. B. J . Am. Chem. Soc. 1973, 95, 7747. (b) Mallory,
F. B.; Mallory, C. W.; Fedarko, M.-C. J . Am. Chem. Soc. 1974, 96, 3536.
(c) Mallory, F. B.; Mallory, C. W.; Ricker, W. M. J . Am. Chem. Soc.
1975, 97, 4770. Mallory, F. B.; Mallory, C. W.; Ricker, W. M. J . Org.
Chem. 1985, 50, 457. Mallory, F. B.; Mallory, C. W.; Baker, M. B. J .
Am. Chem. Soc. 1990, 112, 2577. (d) Ernst, L.; Ibrom, K. Angew. Chem.,
Int. Ed. Engl. 1995, 34, 1881. Ernst, L.; Ibrom, K.; Marat, K.; Mitchell,
R. H.; Bodwell, G. J .; Bushnell, G. W. Chem. Ber. 1994, 127, 1119.
(7) Mallory, F. B.; Luzik, E. D., J r.; Mallory, C. W.; Carroll, P. J . J .
Org. Chem. 1992, 57, 366. Mallory, F. B.; Mallory, C. W. J . Am. Chem.
Soc. 1985, 107, 4816.
(15) (a) Nakanishi, W.; Hayashi, S. Chem. Lett. 1998, 523. (b)
Nakanishi, W.; Hayashi, S. J . Phys. Chem., in press.

6690 J . Org. Chem., Vol. 64, No. 18, 1999
Hayashi and Nakanishi
Ta ble 1. 77Se NMR Ch em ica l Sh ifts a n d Cou p lin g Con sta n ts of 1 a n d 2, Togeth er w ith th e Selected 13C Ch em ica l Sh ifts
a n d Cou p lin g Con sta n tsa
1
2b
Y
δ(8Se)
δ(1Se)
4J (8Se,1Se)
5J (8Se,1′Se)
δ(8Se)
δ(1Se)
4J (8Se,1Se)
δ(CMe
)
1J (1Se,CMe
)
OMe
Me
H
Cl
Br
416.2
422.0
429.0
429.1
429.6
442.5
456.1
541.4
537.4
534.2
534.7
534.0
530.2
529.6
371.6
354.4
341.4
330.1
327.1
311.4
294.1
12.4
11.9
13.6
14.0
c
424.5
427.7
434.3
431.6
432.4
442.4
453.9
233.1
234.5
235.4
234.7
235.2
239.2
240.1
341.6
330.9
322.4
316.7
313.9
294.7
272.5
13.9
13.7
13.4
13.5
13.4
12.9
12.5
71.2
72.8
72.8
72.8
72.7
74.5
76.1
COOEt
NO2
13.7
13.5
a
b
The values of δ(Se) and δ(C) are from external MeSeMe and CDCl3, respectively, and coupling constants are in Hz. Values of
5J (8Se,CMe) were observed to be 15.0-16.1 Hz. c Not observed due to low solubility and low sensitivity.
nylselanyl)naphthyl] diselenides (1-[8-(p-YC6H4Se)C10H6]-
Se-Se[C10H6(SeC6H4Y-p)-8′]-1′ (1: 1a -g for Y ) H, OMe,
Me, Cl, Br, COOEt, NO2, respectively)) were prepared
by the reaction of the dianion of naphtho[1,8-c,d]-1,2-
diselenole with 2 equiv or more of para-substituted
benzenediazonium chloride at low temperature. 1-(Me-
thylselanyl)-8-(para-substituted phenylselanyl)naphtha-
lenes 2 (2a -g) were prepared by the addition of methyl
iodide to aqueous THF solutions of the corresponding
8-(para-substituted phenylselanyl)-1-naphthaleneselena-
tes, which were obtained in the reaction of 1a -g with
sodium borohydride, respectively.
F igu r e 1. Plot of δ(8Se) of 1 versus δ(8Se) of 2: O and x stand
for g(m ) and g(n ), respectively. See also ref 20.
The substituent effect on δ(8Se) of 1 is 1.33 times larger
than that of 2. The selanyl groups at the 1-positions in 1
and 2 must affect the magnitude of the substituent effect
on the δ(8Se) values relative to those of 1-(arylselanyl)-
naphthalenes. Therefore, the larger substituent effect for
1 may be due to the greater electron-accepting ability of
the naphthyl group bearing an Se-Se bond with a low-
lying σ*(Se-Se) orbital in 1 relative to the 8-(methylse-
lanyl)naphthyl group in 2. The conformational effect of
the ArSe group must also play an important role for the
magnitude of the substituent effect. The substituent
effect on the δ(Se) values in p-YC6H4SeR is larger for the
Se-CR bond being in the aryl plane than for the bond
perpendicular to the plane.18,19 The structures 1a and 2a
correspond the planar and the perpendicular ones, re-
spectively.20
The 77Se NMR spectra of 1 and 2 are measured, along
with the 1H and 13C NMR spectra for the compounds.
Table 1 summarizes the 77Se NMR chemical shifts and
coupling constants of 1 and 2, together with selected 13C
chemical shifts. The Se atoms of arylselanyl groups at
8
the 8,8′- and 8-positions in 1 and 2 are numbered as Se
1
(or 8′Se) and other Se atoms in 1 and 2 as Se (or 1′Se).
The δ(8Se) values of 1 show a good correlation with
those of 2. Figure 1 shows the results, and the correlation
is shown in eq 1.16,17
(17) The δ(8Se) values of 1 and 2 were also plotted versus δ(Se) of
1-(para-substituted phenylselanyl)naphthalenes (10), and the correla-
tions are given in eqs c and d, respectively. However, the correlation
for 1 (eq c) is poorer than that of eq a in ref 16. It must be due to the
characteristic structures of 10. Details will be reported elsewhere.
δ(8Se) of 1 )
δ(8Se) of 1 ) 1.51 × δ(Se) of 10 - 116.0 (r ) 0.987) (c)
1.33 × δ(8Se) of 2 - 147.1 (r ) 0.994) (1)
δ(8Se) of 2 ) 1.14 × δ(Se) of 10 + 22.0 (r ) 0.997)
(d)
(16) The δ(8Se) values of 1 and 2 were plotted versus δ(Se) of
p-YC6H4SePh (9), and the correlations are given in eqs a and b,
respectively. As shown in eqs 1, a, and b, the δ(8Se) in 1 and 2 and
δ(Se) in 9 are well correlated with each other, which means that the
effect of the substituents on δ(Se) of the p-YC6H4Se groups would be
essentially the same for the three selenides, although the magnitudes
of the effect are different. A slight deviation was observed for the point
corresponding to Y ) OMe in eq b.
(18) The details of the substituent effect on δ(Se) in p-YC6H4SeR
(R ) Me, Ph, CN, CHdCH2 etc.), together with 1 and 2, are discussed
in ref 15. The δ(8Se) values of 1 and 2 can be discussed as a class of
para-substituted phenyl selenides.
(19) Details of the substituent effect on δ(8Se) and δ(Ci) are discussed
in the Supporting Information.
(20) The results show that the substituent dependence of the
structures 1 and 2 would also be considered for the detail discussion,
since the plot gives better correlations if it is analyzed as the two
correlations with g(m ) (a ) 1.27 and r ) 0.990) and g(n ) (a ) 1.22 and
r ) 1.00) as will be discussed in the plots of 4J (8Se,1Se) () 4J (8′Se,-
1′Se)) versus δ(8Se) in 1 and 2 in the text.
δ(8Se) of 1 ) 1.07 × δ(Se) of 9 - 21.4 (r ) 0.996)
δ(8Se) of 2 ) 0.794 × δ(Se) of 9 + 98.2 (r ) 0.991)
(a)
(b)

Substituent Effect on 77Se NMR Chemical Shifts
J . Org. Chem., Vol. 64, No. 18, 1999 6691
F igu r e 2. Plot of δ(1Se) versus δ(8Se) of 1. Deviation from
linearity is emphasized by a dotted line.
F igu r e 3. Plot of 4J (Se,Se) versus δ(8Se) of 1: O and x stand
for g(m ) and g(n ), respectively.
The δ(1Se) values of 1 and 2 were plotted versus
δ(8Se) of 1 and 2, respectively. Figure 2 shows the plot of
δ(1Se) versus δ(8Se) of 1, and the correlations for 1 and 2
are shown in eqs 2 and 3, respectively.
δ(1Se) of 1 ) -0.282 ×
δ(8Se) of 1 + 656.2 (r ) 0.924) (2)
δ(1Se) of 2 ) 0.252 ×
δ(8Se) of 2 + 126.5 (r ) 0.965) (3)
Figures 3 and 4 exhibit the plots of 4J (8Se,1Se) ()
4J (8′Se,1′Se)) versus δ(8Se) in 1 and 2, respectively. Each
plot was better analyzed as the two correlations depend-
ing on the two groups of substituents, g(m ) and g(n ):
g(m ) consists of the points corresponding to Y ) OMe,
Me, and H, and the points of Y ) Cl, Br, COOEt, and
NO2 belong to g(n ). The correlations for g(m ) and g(n )
are given in eqs 4m,n and 5m,n for 1 and 2, respectively.
F igu r e 4. Plot of 4J (Se,Se) versus δ(8Se) of 2: O and x stand
for g(m ) and g(n ), respectively.
4J (8Se,1Se) of 1 ) -2.34 ×
δ(8Se) of 1 + 1345.2 (r ) 0.991 for g(m )) (4m)
4J (8Se,1Se) of 1 ) -1.29 ×
δ(8Se) of 1 + 883.5 (r ) 0.998 for g(n )) (4n)
4J (8Se,1Se) of 2 ) -1.86 ×
δ(8Se) of 2 + 1128.7 (r ) 0.965 for g(m )) (5m)
4J (8Se,1Se) of 2 ) -1.96 ×
δ(8Se) of 2 + 1161.0 (r ) 1.000 for g(n )) (5n)
Figure 5 shows the plot of J (8Se,1Se) of 1 versus those
of 2. The plot is also analyzed with g(m ) and g(n ), of
which correlations are given in eqs 6m,n, respectively.
4
4
4
F igu r e 5. Plot of J (Se,Se) of 1 versus J (Se,Se) of 2: O and
x stand for g(m ) and g(n ), respectively.
4J (8Se,1Se) of 1 ) 1.57 ×
tions in 1 and 2. As shown in Figure 2 and eq 2, the plot
of δ(1Se) versus δ(8Se) in 1 gave a rather poor correlation
with a negative proportionality constant (inverse cor-
relation) so the plots had to be analyzed as inversely
proportional shown by a dotted line in the Figure. On
the other hand, a better correlation was held with a
positive proportionality constant for 2 (regular correla-
tion; see eq 3).
4J (8Se,1Se) of 2 - 166.3 (r ) 1.000 for g(m )) (6m)
4J (8Se,1Se) of 1 ) 0.809 ×
4J (8Se,1Se) of 2 + 73.4 (r ) 1.000 for g(n )) (6n)
Now, we would like to discuss the substituent effect
on δ(1Se), resulting from the nonbonded Se- - -Se interac-

6692 J . Org. Chem., Vol. 64, No. 18, 1999
Hayashi and Nakanishi
Regular correlation in 2 could be explained by assum-
ing that the electron density on the Se atom decreased
δ(CMe) of 2 ) -0.048 ×
δ(8Se) of 2 + 34.1 (r ) 0.993) (7)
1
as that on the 8Se atom became smaller, if the δ(8Se) and
δ(1Se) values are mainly governed by the charges on the
atoms. However, there are other explanations for the
regular correlation. One of mechanisms is to consider the
1Se-CMe bond polarization induced by the charge on the
8Se atom. Since the electron density near the two Se
atoms in 2 should be very high due to the very close
location of the two Se atoms, the electrons on the Se
atoms must be expelled to the adjacent atoms or the
1J (1Se,CMe) of 2 ) 0.154 ×
δ(8Se) of 2 + 6.5 (r ) 0.973) (8)
Good correlations were obtained for these plots, which
demonstrated that the influence of the substituents at
the phenyl para positions was transmitted even to the
δ(CMe) and 1J (1Se,CMe) values. These results can be
explained by assuming that the fairly large interaction
1
Se-C bonds. The expelled electrons from the Se atom
8
is operating between the lone pairs of the Se atom and
may return to the atom, if the electron density on the
8Se atom decreased, which must result in the increase
of the electron density at the 1Se atom. The observed
regular correlation in 2 can be achieved only when the
δ(8Se) and δ(1Se) values shift downfield and upfield,
respectively, as the charges at the Se atoms become
larger, in this explanation. The contribution of the
through-bond interaction must also be considered, since
the π type 2c-4e orientation of the p-type lone pairs
enables them to interact easily with the π-orbitals of the
naphthalene ring of 2.
8
the σ*(1Se-CMe) orbital. The Se- - -1Se-CMe interaction
can be accounted for by the contribution of the unsym-
metrical 3c-4e model,21 as was observed in the F- - -Se-
C interaction.5 Ab initio MO calculations were performed
on appropriate models of 1 and 2, which reveal the nature
of the nonbonded interactions of 4c-6e type in 1 and π
type 2c-4e and/or n(Se)- - -σ*(Se-C) 3c-4e in 2.
Na tu r e of th e Non bon d ed Se- - -Se In ter a ction s
Revea led by MO Ca lcu la tion s. Chart 3 shows some
adducts, p-YC6H4ASeH- - -BSeH-BSeH- - -HASeC6H4Y-p
(3: models of 1) and p-YC6H4ASeH- - -BSeH2 (4 and 5:
model of 2), where the naphthylidene and methyl groups
in 1 and 2 are replaced by hydrogens in the models. The
structures 3-5 around the Se atoms are deformed but
remained close to those of 1a , 2a , and 2d , respectively.
Ab initio molecular orbital calculations on 3-5 were
performed with the 6-311+G(2d,p) basis sets of the
Gaussian 94 program22 at the B3LYP level. Similar
calculations were also performed on p-YC6H4SeH (6p l and
6p d ),23 where the Se-H bond is in the aryl plane in 6p l
and it is perpendicular to the plane in 6p d . Ab initio MO
calculations of 3-6 were carried out for Y ) H, OH, Me,
Cl, Br, COOH, and NO2. The GIAO magnetic shielding
tensor11,12 for the Se nucleus (σ(Se)) and the natural
charges (Qn) were also obtained using the natural
population analysis.24
The mechanism operating in the inverse correlation
in 1 must be different from that of the regular correlation
in 2. It is reasonable to assume that the σ*-orbital of the
8
inside Se-Se bond can accept electrons of the Se atoms
8
more easily when the electron density of the Se atoms
1
increases. The electron density at the Se atom will be
effectively increased, as the density at the 8Se atoms
becomes larger, in this case. The NMR signals of both
1
8Se and Se atoms in 1 would shift in the same direction,
if the chemical shifts are mainly determined by the
charges on the atoms. However, the observations are just
the opposite of what is expected. Therefore, the δ(1Se)
values must be negatively proportional to the charges in
this case. Ab initio MO calculations, containing the σ-
(Se) values calculated based on the GIAO theory, will
reveal the details, which will be discussed in the next
section.
The optimized structure of 6p l was employed in 3 and
5 and 6p d in 4 without further optimization, except for
r(Se-C), r(Se-H), and CSeH, which were reoptimized
in the models. As shown in Chart 3, the four Se atoms
in 3 were placed on the x axis. Se-C bonds were on the
y or z direction. The aryl plane was on the yz plane.
Nonbonded Se- - -Se distances, r(ASe-BSe), were fixed at
After establishment of the inverse correlation of
δ(1Se) versus δ(8Se) in 1 experimentally, together with
the regular correlation in 2, the next extension of our
study is to examine the nonbonded interaction by
means of coupling constants in connection with δ(8Se)
in 1 and 2. The plot of 4J (Se,Se) versus δ(8Se) in 1
was analyzed as two correlations as shown in Figure 3
and eqs 4m,n. The plot in 2 was similarly analyzed as
the two correlations (Figure 4 and eqs 5m,n). The
analysis by the two correlation methods show the im-
portance of the substituent dependence on structures. All
of the proportionality constants in eqs 4 and 5 were
(21) (a) Pimentel, G. C. J . Chem. Phys. 1951, 19, 446. Musher, J . I.
Angew. Chem., Int. Ed. Engl. 1969, 8, 54. (b) Chen, M. M. L.; Hoffmann,
R. J . Am. Chem. Soc. 1976, 98, 1647. (c) Cahill, P. A.; Dykstra, C. E.;
Martin, J . C. J . Am. Chem. Soc. 1985, 107, 6359. See also: Hayes, R.
A.; Martin, J . C. Sulfurane Chemistry. In Organic Sulfur Chemistry:
Theoretical and Experimental Advances; Bernardi, F., Csizmadia, I.
G., Mangini, A., Eds.; Elsevier: Amsterdam, 1985; Chapter 8.
(22) Gaussian 94, Revision D.4: Frisch, M. J .; Trucks, G. W.;
Schlegel, H. B.; Gill, P. M. W.; J ohnson, B. G.; Robb, M. A.; Cheeseman,
J . R.; Keith, T.; Petersson, G. A.; Montgomery, J . A.; Raghavachari,
K.; Al-Laham, M. A.; Zakrzewski, V. G.; Ortiz, J . V.; Foresman, J . B.;
Cioslowski, J .; Stefanov, B. B.; Nanayakkara, A.; Challacombe, M.;
Peng, C. Y.; Ayala, P. Y.; Chen, W.; Wong, M. W.; Andres, J . L.;
Replogle, E. S.; Gomperts, R.; Martin, R. L.; Fox, D. J .; Binkley, J . S.;
Defrees, D. J .; Baker, J .; Stewart, J . P.; Head-Gordon, M.; Gonzalez,
C.; Pople, J . A. Gaussian, Inc., Pittsburgh, PA, 1995.
(23) The structures 6p l and 6p d (a -g for Y ) H, OH, Me, Cl, Br,
COOH, and NO2, respectively) were full optimized with the 6-311+G-
(2d,p) basis sets at the B3LYP level except for 6p d with Y ) COOH.
Calculations for 6p d with Y ) COOH were achieved with the torsional
angle between the Se-H bond and the phenyl plane fixed to be
perpendicular. The structures 6p l and 6p d would not be the energy
minima but the transition states.15b
4
negative, which implies that as the value for J (8Se,1Se)
in 1 and 2 becomes smaller, then the δ(8Se) experiences
a downfield shift. The results are explained well by
assuming that the J values become larger as the electron
density of the 8Se atoms increases. The observation of
5
5
the long-range J (8Se,1′Se) (and J (1Se,8′Se)) couplings of
12-14 Hz in 1 further supports the effective orbital
interaction between the 8Se atom with the σ*(Se-Se)
orbital in 1.
1
The δ(CMe) and J (1Se,CMe) values were plotted versus
those of δ(8Se) in 2, of which correlations are given in
(24) NBO Ver. 3.1: Glendening, E. D.; Reed, A. E.; Carpenter, J .
E.; Weinhold, F.
eqs 7 and 8, respectively.

Substituent Effect on 77Se NMR Chemical Shifts
J . Org. Chem., Vol. 64, No. 18, 1999 6693
The nonbonded Se- - -Se distance (r(ASe-BSe)) was also
fixed at 3.070 Å. The r(Se-H), r(C-Se), CSeH, and
HSeH were optimized.
Ch a r t 3. Str u ctu r es of Mod els 3-6, Togeth er
w ith th e Axes
Structures 3 were optimized in the limited conditions
with the B3LYP/6-311+G(2d,p) method. The natural
population analysis could not be achieved with the
method due to the “strongly delocalized NBO set” in the
calculations; therefore, natural charges were obtained
with the B3LYP/3-21G* method, using the structures
obtained by the B3LYP/6-311+G(2d,p) method. The σ-
(Se) value of 3f was not obtained by the B3LYP/6-311+G-
(2d,p) method due to “consistency failure” in the calcu-
lations. Thus, the σ(Se) values of 3 were calculated with
the 6-311+G(2d,p) basis sets at the Hartree-Fock (HF)
level. Table 2 exhibits the results of MO calculations for
3 where the σ(Se) values are given by the calculated δ-
(Se) values, which are defined as -(σ(Se) - σ(Se)MeSeMe).
Structures 4 and 5 were also optimized in the limited
conditions with the B3LYP/6-311+G(2d,p) method. While
the Qn and σ(Se) values for 5 were obtained with the
method, the σ(Se) values for 4f and 4g could not be
obtained by the method. Therefore, the σ(Se) values of 4
were recalculated with the HF/6-311+G(2d,p) method.
Table 3 summarizes the results obtained for 4 and 5.
Correlations between the calculated values in 3-5 are
summarized in Table 4.
Ta ble 2. Resu lts of a b In itio MO Ca lcu la tion s on 3 w ith
th e 6-311+G(2d ,p ) Ba sis Setsa ,b
c
c
d
d
e
e
Y
Qn(ASe)B Qn(BSe)B δ(ASe)B δ(BSe)B δ(ASe)H δ(BSe)H
OH
Me
H
Cl
Br
0.2075
0.2107
0.2137
0.2239
0.2231
0.2315
-0.1686 108.26 -28.99 132.15
-0.1670 112.13 -28.71 137.11
-0.1665 120.26 -28.77 145.92
-0.1657 120.50 -28.07 148.59
-0.1657 120.50 -28.06 149.79
2.32
1.98
1.41
1.08
0.89
CO-
OH
-0.1640
f
f
165.60 -1.54
Let us discuss the characteristics of the interaction of
4c-6e in 3 first, based on the results of ab initio MO
calculations shown in Table 4 (nos. 1-7). The Qn(BSe)B
values correlate well with those of Qn(ASe)B, where the
subscript B stands for the B3LYP level. The results fur-
ther show that the magnitude of the charge transfer from
NO2
0.2460
-0.1620 149.10 -24.46 175.21 -2.09
a
The σ(Se) values for MeSeMe are 1645.53 and 1915.42
with B3LYP/6-311+G(2d,p) and HF/6-311+G(2d,p)//B3LYP/6-
b
311+G(2d,p) methods, respectively. Subscripts B and H show
B3LYP and HF levels, respectively. c Calculated with the B3LYP/
d
B
ASe to Se in 3 becomes greater as the electron density
3-21G*//B3LYP/6-311+G(2d,p) method. Calculated with the
B3LYP/6-311+G(2d,p) method. e Calculated with the HF/6-
311+G(2d,p)//B3LYP/6-311+G(2d,p) method. f Not obtained due to
“consistency failure” in the calculations.
on ASe increases, which must be a reflection of the n(A-
Se)- - -σ*(BSe-BSe)- - -n(ASe)-type interaction of the bond.
While δ(BSe)B correlated with δ(ASe)B accompanied by a
positive proportionality constant of 0.115, the propor-
tionality constant was -0.111 in the correlation between
δ(BSe)H and δ(ASe)H, where the subscript H means the
HF level. Computation at the B3LYP level could not
explain the observed values. This discrepancy arises from
the positive proportionality constant in the correlation
of δ(BSe)B versus Qn(BSe)B (no. 3). The value is negative
in the correlation of δ(BSe)H with Qn(BSe)B (no. 6). The
calculations at the B3LYP level usually explain the
observed values better than those at the HF level.14,15
However, the results at the HF level reproduced the
observed substituent effect on δ(1Se) of 1 but those at the
B3LYP level did not, in this case. The superior nature of
the calculations at the DFT (B3LYP) level comes from
the observed value of 3.053 Å in 1a . The two BSe-Hb
bonds of the central H2Se2 component were placed on the
xz and xy planes. The r(Se-H), r(Se-C), r(BSe-BSe), CA-
SeHa, and BSeBSeHb were optimized. The arylselanyl
B
group and the Se and Hb atoms in 4 were placed on the
xz plane. The CASeBSe and ASeBSeHb were fixed at
the observed values of 157.0° and 144.4°, respectively,
and the nonbonded Se- - -Se distance (r(ASe-BSe)) was
fixed at the observed value of 3.070 Å in 2a . Two other
Se-H bonds were in the plane perpendicular to the xz
plane, and the r(Se-H), r(Se-C), CSeH, and HSeH
were optimized. The components of 5, p-YC6H4SeH and
HSeH, were located in the yz and xy planes, respectively,
with the C-Se and Se- - -Se-H bonds on the z and x axes.
Ta ble 3. Resu lts of a b In itio MO Ca lcu la tion s on 4 a n d 5 w ith th e B3LYP /6-311+G(2d ,p ) Meth od a ,b
4
5
Y
Qn(ASe) Qn(BSe) Qn(Hb) δ(ASe) δ(BSe) δ(Hb) δ(ASe)c δ(BSe)c δ(Hb)c Qn(ASe) Qn(BSe) Qn(Hb) δ(ASe) δ(BSe) δ(Hb)
OH
Me
H
Cl
Br
0.0882 -0.1669 0.0816 30.56 -400.01 1.769 77.59 -239.53 2.103 0.1704 -0.2022 0.0572 104.79 -389.24 2.055
0.0855 -0.1669 0.0814 37.59 -399.56 1.783 83.20 -239.09 2.109 0.1731 -0.2013 0.0573 108.48 -389.23 2.044
0.0861 -0.1668 0.0821 49.99 -398.76 1.801 92.75 -238.71 2.130 0.1776 -0.2019 0.0586 115.35 -387.28 2.071
0.0923 -0.1671 0.0844 39.47 -398.34 1.809 88.36 -238.78 2.153 0.1857 -0.2037 0.0615 118.21 -386.56 2.092
0.0926 -0.1671 0.0845 39.70 -397.96 1.812 89.28 -238.47 2.157 0.1869 -0.2038 0.0618 117.89 -386.18 2.095
CO-
OH
0.0924 -0.1669 0.0850
d
d
d
99.30 -238.04 2.180 0.1998 -0.2045 0.0639 137.43 -385.84 2.094
NO2
0.0994 -0.1672 0.0881
d
d
d
102.05 -239.38 2.227 0.2154 -0.2065 0.0683 150.20 -384.20 2.130
a
The σ(Se) values for MeSeMe are 1645.53 and 1915.42 with B3LYP/6-311+G(2d,p) and HF/6-311+G(2d,p)//B3LYP/6-311+G(2d,p)
b
methods, respectively. The σ(H) values for TMS are 31.945 and 32.198 with B3LYP/6-311+G(2d,p) and HF/6-311+G(2d,p)//B3LYP/6-
311+G(2d,p) methods, respectively. c Calculated with the HF/6-311+G(2d,p)//B3LYP/6-311+G(2d,p) method. Not obtained due to
d
“consistency failure” in the calculations.

6694 J . Org. Chem., Vol. 64, No. 18, 1999
Hayashi and Nakanishi
Ta ble 4. Cor r ela tion s betw een Ca lcu la ted Va lu es for
3-5a ,b
no.
Y
X
a
b
r
n
1
2
3
4
5
6
7
8
9
Qn(BSe)B of 3 Qn(ASe)B of 3
0.156
-0.2004 0.981 7
-96.85
93.85
-41.86
-94.45
-126.93
17.35
δ(ASe)B of 3 Qn(ASe)B of 3 990.2
δ(BSe)B of 3 Qn(BSe)B of 3 733.5
0.967 6c
0.948 6c
0.970 6c
0.974 7
0.957 7
0.985 7
δ(BSe)B of 3 δ(ASe)B of 3
0.115
δ(ASe)H of 3 Qn(ASe)B of 3 1102.2
δ(BSe)H of 3 Qn(BSe)B of 3 -769.8
δ(BSe)H of 3 δ(ASe)H of 3
Qn(BSe)B of 4 Qn(ASe)B of 4
Qn(Hb)B of 4 Qn(ASe)B of 4
-0.111
-0.026
-0.1646 0.860 7
0.0397 0.978 7
0.486
10 δ(ASe)H of 4 Qn(ASe)B of 4 1223.2
-20.87
-136.62
0.686 7
0.172 7
11 δ(BSe)H of 4 Qn(BSe)B of 4 612.2
12 δ(Hb)H of 4
Qn(Hb)B of 4
17.79
0.025 -241.15
0.0045
-0.108
0.249
0.659 0.985 7
0.419 7
1.742 0.901 7
-0.1833 0.963 7
0.0147 0.993 7
13 δ(BSe)H of 4 δ(ASe)H of 4
14 δ(Hb)H of 4
δ(ASe)H of 4
15 Qn(BSe)B of 5 Qn(ASe)B of 5
16 Qn(Hb)B of 5 Qn(ASe)B of 5
F igu r e 6. Plot of δ(1Se) of 1 versus δ(BSe)H of 3: O and x
stand for g(m ) and g(n ), respectively.
17 δ(ASe)B of 5 Qn(ASe)B of 5 1006.9
-66.52
-580.07
0.988 7
0.928 7
18 δ(BSe)B of 5 Qn(BSe)B of 5 -949.5
19 δ(Hb)B of 5
Qn(Hb)B of 5
δ(ASe)B of 5
6.968
0.102 -399.40
0.0016
1.656 0.965 7
0.910 7
1.891 0.889 7
respectively,
20 δ(BSe)B of 5 δ(ASe)B of 5
21 δ(Hb)B of 5
Yδ-rC6H4-Seδ+- - -Seδ--Hb
(11)
(12)
δ+
a
b
Y ) aX + b (r: correlation coefficient). Subscripts B and H
show B3LYP and HF levels, respectively. c Without the point for
Y ) COOH.
down
Yδ-rC6H4-Sedown- - -Sedown-Hb
inclusion of the electron correlation effect in the calcula-
tions, but the method sometimes overestimates this
effect.14 This overestimation of the electron correlation
effect at the B3LYP level might lead to failure. The
characters in the substituent effect on the atomic charges
and the δ(Se) values of 3 are shown in eqs 9 and 10,
respectively, assuming Y is electron withdrawing. The
superscript up (or down) in eq 10 shows upfield (or
downfield) shifts in the δ(Se) values.
exemplified by the electron-withdrawing group of Y. The
δ(CMe) values in 2 go upfield when Y ) electron-
withdrawing, which is just the opposite of that predicted
for Hb shown in eq 12. The discrepancy may arise from
the difference between H in 5 and CH3 in 2: the C-H
bond in 2 can also be polarized.
Yδ-rC6H4-Seδ+- - -Seδ+-Seδ+- - -Seδ+-C6H4fYδ-
(9)
Yδ-rC6H4-Sedown- - -Seup-Seup- - -Sedown
-
C6H4fYδ- (10)
Glass and co-workers have shown that the p-type lone
pairs of sulfur atoms in naphtho[1,8-b,c]-1,5-dithiocin (7)
lie in the naphthyl plane and interact directly with each
other, whereas those in 1,8-bis(methylthio)naphthalene
(8) mainly interact with the π-orbitals of the naphthalene
ring.8 The orientation of the lone pairs of Se atoms in
PhSe groups of 1a is close to that in the S atoms of the
former, whereas that of the Se atoms in 2a is very similar
to that in S atoms of the latter. The role of the π-frame-
work must be important in the transmittance of the
substituent effect in 2 as discussed in 4.
Th e Cor r ela tion of Obser ved a n d Ca lcu la ted
Va lu es. The observed NMR parameters are plotted
versus the calculated ones. The correlations of δ(8Se) of
1 versus δ(ASe)B and δ(ASe)H in 3 are shown in eqs 13
and 14, respectively. The a and r values in eq 13 are very
close to 1.0, which suggests that 3 can be a good model
of 1, as a first approximation. The δ(1Se) values of 1 are
plotted versus δ(BSe)H of 3. The plot is shown in Figure
6 and is analyzed as two correlations with g(m ) and g(n ),
which are shown in eqs 15m and 15n, respectively. The
necessity of needing two correlations may be due to the
conformational effects of the phenyl group in 1 (see also
Chart 1). A plot of δ(8Se) of 2 versus δ(ASe)B of 5 is
similarly analyzed by the two correlation methods, which
are shown in eqs 16m and 16n, respectively. The results
The correlations in 4 are shown in Table 4 (nos. 8-14),
which are mainly the results of the HF level. The p-type
lone pairs of the Se atoms in 2a can interact through π
orbitals of the naphthalene ring, as was shown in the
sulfur analogue. The mechanism of the substituent effect
on δ(1Se) in 2 would be through-bond by way of the
naphthylidene π-system, if the structures 2 are very close
to that of 2a . The results of the calculations on 4 are in
accordance of the expectation. Nevertheless, the BSe-
Hb polarization mechanism is predicted to operate in 4.
Correlations with 5 exhibit the typical characters
expected for the ASe- - -BSe-Hb 3c-4e type interaction
(Table 4, nos. 15-21). The observed δ(Se) values in 2 can
be well explained by the results of the calculations on 5
at least in a qualitative sense. The proportionality
constant of no. 20 in Table 4 (0.102) is smaller than that
of eq 3 (0.252), which may be due to the contribution of
a mechanism other than 5 such as the through-bond
mechanism discussed above. We believe that the mech-
anism shown for 5 is substantially the same as that
operating in 2d -g. This mechanism may also be operat-
ing in 2a -c, as well as a through-bond mechanism. The
nature of the substituent effect on the atomic charges
and the δ(Se) values are shown in eqs 11 and 12,

Substituent Effect on 77Se NMR Chemical Shifts
J . Org. Chem., Vol. 64, No. 18, 1999 6695
4
suggest the contribution of mechanism 5 for the trans-
mittance of substituent effects in 2.
plot of J (8Se,1Se) of 1 versus those of 2 (eqs 6m,n) may
shed light on the situation discussed above.
Further study on the nonbonded interactions contain-
ing the Se atom(s) is currently in progress.
δ(8Se) of 1 ) 0.953 ×
δ(ASe)B of 3 + 314.2 (r ) 0.999) (13)
Exp er im en ta l Section
δ(8Se) of 1 ) 0.869 ×
Chemicals were used without further purification unless
otherwise noted. Solvents were purified by standard methods.
Melting points were uncorrected. 1H, 13C, and 77Se NMR
spectra were measured at 400, 100, and 76 MHz, respectively,
with a J EOL J NM-LA 400 spectrometer. The 1H, 13C, and
77Se chemical shifts are given in ppm relative to those of
internal CHCl3 slightly contaminated in the solution, CDCl3
as the solvent, and external MeSeMe, respectively. Column
chromatography was performed on silica gel (Fuji Silysia BW-
300), acidic alumina and basic alumina (E. Merk).
P r ep a r a tion . The diselenide 1a 1 and the bis-selenide 2a 1
were prepared by the same method as shown in the previous
paper. The selenides p-YC6H4SePh (9) were prepared similarly
to the method shown in the literature.15b,30,31 The reaction of
p-iodonitrobenzene with sodium benzeneselenate in ethanol
was more effective to prepare 9g.
1a : mp 162-163 °C (lit.1 mp 161-163 °C). 2a : mp 101.5-
102.5 °C (lit.1 mp 101.5-102.5 °C). 9b: mp 45-46 °C (lit.30
mp 45-46 °C). 9c: colorless oil; bp 100-101 °C/1 mmHg (lit.30
bp 100 °C/1 mmHg). 9d : colorless oil; bp 148-149 °C/1 mmHg
(lit.30 bp 145-150 °C/1 mmHg). 9e: mp 32-33 °C (lit.30 mp
32 °C). 9f: colorless oil.15b 9g: mp 58-59 °C (lit.15b,31 mp 58
°C).
δ(ASe)H of 3 + 301.2 (r ) 0.990) (14)
δ(1Se) of 1 ) 7.675 ×
δ(BSe)H of 3 + 523.1 (r ) 0.978 for g(m )) (15m)
δ(1Se) of 1 ) 1.585 ×
δ(BSe)H of 3 + 532.8 (r ) 0.997 for g(n )) (15n)
δ(8Se) of 2 ) 0.932 ×
δ(ASe)B of 5 + 326.7 (r ) 1.000 for g(m )) (16m)
δ(8Se) of 2 ) 0.657 ×
δ(ASe)B of 5 + 354.1 (r ) 0.991 for g(n )) (16n)
We would like to comment on the J (8Se,1Se) values of
4
1 and 2 next, although the J values were not calculated.
4
The J (8Se,1Se) values of 1 and 2 are plotted versus Qn-
(ASe)B of 3 and 5, respectively, of which correlations are
given in eqs 17 and 18. The negative proportionality
constants in eqs 17 and 18 clearly show that the J values
become larger if the electron density on the ASe atoms
increases, as suggested in the previous section. The
correlation coefficient of eq 17 is smaller than that of eq
18.
Bis[8-(p -m et h oxyp h en ylsela n yl)n a p h t h yl]-1,1′-d ise-
len id e (1b). To a solution of the dianion of naphtho[1,8-c,d]-
1,2-diselenole, which was prepared by reduction of the dise-
lenole with NaBH4 in an aqueous THF, was added p-methoxy-
benzenediazonium chloride at low temperature. After usual
workup, the solution was chromatographed on silica gel
containing acidic and basic alumina. Recrystallization of the
chromatographed product from hexane gave 1b as a yellow
solid: 69% yield; mp 143.5-145.0 °C; 1H NMR (CDCl3, 400
MHz) 3.74 (s, 6H), 6.75 (dd, 4H, J ) 8.9, 2.6 Hz), 7.18 (t, 2H,
J ) 7.8 Hz), 7.32 (t, 2H, J ) 7.6 Hz), 7.32 (dd, 4H, J ) 9.0, 2.7
Hz), 7.67 (dd, 2H, J ) 8.0, 0.9 Hz), 7.79 (dd, 2H, J ) 8.1, 1.0
Hz), 7.86 (dd, 2H, J ) 7.2, 1.4 Hz), 8.14 (dd, 2H, J ) 7.5, 1.0
Hz); 13C NMR (CDCl3, 100 MHz) 55.27, 115.06, 125.28, 125.82,
126.52, 128.33, 129.78, 130.25, 130.57, 132.74, 133.42, 135.39,
136.14, 137.39, 159.24; 77Se NMR (CDCl3, 76 MHz) 416.2, 541.4
(4J (8Se,1Se) ) 371.6 Hz). Anal. Calcd for C34H26O2Se4: C, 52.19;
H, 3.35. Found: C, 52.45; H, 3.36.
4J (8Se,1Se) of 1 ) -1877 ×
Qn(ASe)B of 3 + 750.2 (r ) 0.969) (17)
4J (8Se,1Se) of 2 ) -1439 ×
Qn(ASe)B of 5 + 582.4 (r ) 0.993) (18)
Although there are some common terms in the equa-
tions for the δ(Se)25 and J (Se,Se)26 values, one must be
careful when the mechanism of the nuclear couplings is
considered in relation to the chemical shifts. The contri-
bution of the 4s-orbitals of the Se atoms to J (Se,Se)27,28
is in striking contrast to the significant contribution of
the 4p atomic orbitals to the diamagnetic term of the δ-
(Se) values. A through-space mechanism must be operat-
ing for the nonbonded Se- - -Se nuclear spin-spin cou-
plings, even if the substituent effect on the remote atomic
charges is effectively transmitted through the π-frame-
work as expected in 2 and which is missing in 4 and 5.29
The correlations of the Qn, δ(Se), with the J values for 1
show that this effect is transmitted by a through-space
mechanism in contrast to the situation in 2. The mech-
anism for 2 would change from mainly 4 for g(m ) to
mainly 5 for g(n ). Analysis of the two correlations for the
Bis[8-(p -m e t h ylp h e n ylse la n yl)n a p h t h yl]-1,1′-d ise -
len id e (1c). Following a method similar to that for 1b, 1c gave
72% yield as a yellow solid: mp 165.5-166.5 °C; 1H NMR
(CDCl3, 400 MHz) 2.27 (s, 6H), 7.00 (dd, 4H, J ) 8.3, 2.5 Hz),
7.16 (t, 2H, J ) 7.8 Hz), 7.20 (dd, 4H, J ) 8.2, 2.5 Hz), 7.34 (t,
2H, J ) 7.9 Hz), 7.67 (dd, 2H, J ) 8.1, 0.8 Hz), 7.83 (dd, 2H,
J ) 8.2, 1.2 Hz), 7.92 (dd, 2H, J ) 7.2, 1.3 Hz), 8.11 (dd, 2H,
J ) 7.5, 1.0 Hz); 13C NMR (CDCl3, 100 MHz) 21.06, 125.84,
126.57, 128.16, 128.40, 130.09, 130.49, 130.66, 130.86, 131.68,
132.32, 135.62, 136.15, 136.79, 138.37; 77Se NMR (CDCl3, 76
MHz) 422.0, 537.4 (4J (8Se,1Se) ) 354.4 Hz). Anal. Calcd for
C
34H26Se4: C, 54.42; H, 3.49. Found: C, 54.71; H, 3.57.
B is [8-(p -c h lo r o p h e n y ls e la n y l)n a p h t h y l]-1,1′-d is e -
len id e (1d ). Following a method similar to that for 1b, 1d
gave 68% yield as a yellow solid: mp 185.0-186.0 °C; 1H NMR
(CDCl3, 400 MHz) 7.13 (br s, 8H), 7.16 (t, 2H, J ) 7.8 Hz),
7.38 (t, 2H, J ) 7.7 Hz), 7.70 (dd, 2H, J ) 8.0, 0.8 Hz), 7.88
(dd, 2H, J ) 8.2, 1.1 Hz), 7.94 (dd, 2H, J ) 7.2, 1.3 Hz), 8.02
(dd, 2H, J ) 7.5, 1.1 Hz); 13C NMR (CDCl3, 100 MHz) 125.95,
126.75, 127.26, 128.43, 129.42, 130.19, 131.28, 131.65, 132.48,
132.91, 133.82, 135.62, 136.36, 139.01; 77Se NMR (CDCl3, 76
(25) Karplus, M.; Pople, J . A. J . Chem. Phys. 1963, 38, 2803.
(26) McConnell, H. M., J . Chem. Phys. 1956, 24, 460.
(27) Reich, H. J .; Trend, J . E. J . Chem. Soc., Chem. Commun. 1976,
310.
(28) Nakanishi, W.; Ikeda, Y. Bull. Chem. Soc. J pn. 1983, 56, 1161.
(29) The contribution of the through-bond mechanism is estimated
to be very small for 4J (F,F) in 1,8-di(fluoro)naphthalene.6b
(30) Greenberg, B.; Gold, E. S.; Burlant, WM. J . Am. Chem. Soc.
1956, 78, 4028.
(31) Chem. Abstr. 1955, 49, 2349g.

6696 J . Org. Chem., Vol. 64, No. 18, 1999
Hayashi and Nakanishi
MHz) 429.1, 534.7 (4J (8Se,1Se) ) 330.1 Hz). Anal. Calcd for
8.6, 2.2 Hz), 7.24 (t, 1H, J ) 7.7 Hz), 7.31 (dd, 2H, J ) 8.8, 2.2
Hz), 7.36 (t, 1H, J ) 7.7 Hz), 7.60 (dd, 1H, J ) 7.3, 1.5 Hz),
7.71 (dd, 1H, J ) 7.1, 1.2 Hz), 7.73 (dd, 1H, J ) 6.8, 1.1 Hz),
7.74 (dd, 1H, J ) 7.3, 1.2 Hz); 13C NMR (CDCl3, 100 MHz)
13.43 (1J ) 72.8 Hz, 5J ) 15.7 Hz), 125.96, 125.99, 128.42,
129.49, 130.86, 131.72, 132.67, 133.50, 133.60, 134.49 (1J )
12.4 Hz), 135.26, 135.59, 135.83; 77Se NMR (CDCl3, 76 MHz)
C
32H20Se4Cl2: C, 48.58; H, 2.55. Found: C, 48.77; H, 2.56.
B is [8-(p -b r o m o p h e n y ls e la n y l)n a p h t h y l]-1,1′-d is e -
len id e (1e). Following a method similar to that for 1b, 1e gave
72% yield as a yellow solid: mp 203.0-205.0 °C; 1H NMR
(CDCl3, 400 MHz) 7.06 (dd, 4H, J ) 6.6, 2.2 Hz), 7.16 (t, 2H,
J ) 7.8 Hz), 7.27 (dd, 4H, J ) 8.6, 2.2 Hz), 7.38 (t, 2H, J ) 7.6
Hz), 7.70 (dd, 2H, J ) 8.1, 0.9 Hz), 7.89 (dd, 2H, J ) 8.2, 1.2
Hz), 7.95 (dd, 2H, J ) 7.1, 1.3 Hz), 8.01 (dd, 2H, J ) 7.5, 1.1
Hz); 13C NMR (CDCl3, 100 MHz) 120.77, 125.95, 126.78,
126.85, 128.40, 130.02, 131.38, 131.71, 132.28, 132.29, 134.56,
135.54, 136.32, 139.19; 77Se NMR (CDCl3, 76 MHz) 429.6, 534.0
(4J (8Se,1Se) ) 327.1 Hz). Anal. Calcd for C32H20Se4Br2: C,
43.67; H, 2.29. Found: C, 43.84; H, 2.25.
431.6, 234.7 (4J (8Se,1Se) ) 316.7 Hz). Anal. Calcd for C17H13
-
Se2Cl1: C, 49.72; H, 3.19. Found: C, 49.77; H, 3.23.
1-(Meth ylsela n yl)-8-(p-br om op h en ylsela n yl)n a p h th a -
len e (2e). Following a method similar to that for 2b, 2e gave
88% yield as a white solid: mp 90.0-91.0 °C; 1H NMR (CDCl3,
400 MHz) 2.34 (s, 3H, J (Se,H) ) 13.9 Hz), 7.23 (dd, 2H, J )
8.6, 2.2 Hz), 7.25 (t, 1H, J ) 7.8 Hz), 7.34 (dd, 2H, J ) 8.6, 2.2
Hz), 7.37 (t, 1H, J ) 7.7 Hz), 7.62 (dd, 1H, J ) 7.4, 1.2 Hz),
7.72 (dd, 1H, J ) 7.5, 1.2 Hz), 7.74 (dd, 1H, J ) 7.6, 1.2 Hz),
7.74 (dd, 1H, J ) 7.6, 1.3 Hz); 13C NMR (CDCl3, 100 MHz)
13.40 (1J ) 72.7 Hz, 5J ) 15.7 Hz), 121.57, 125.98, 126.01,
128.40, 129.57, 130.63, 131.77, 132.40 (1J ) 10.7 Hz), 132.58,
134.38, 134.50 (1J ) 11.6 Hz), 135.29, 135.79, 135.84; 77Se
NMR (CDCl3, 76 MHz) 432.4, 235.2 (4J (8Se,1Se) ) 313.9 Hz).
Anal. Calcd for C17H13Se2Br1: C, 44.87; H, 2.88. Found: C,
44.89; H, 2.90.
1-(Meth ylsela n yl)-8-[p-(eth oxyca r bon yl)p h en ylsela n y]-
n a p h th a len e (2f). Following a method similar to that for 2b,
2f gave 84% yield as a white solid: mp 83.5-84.0 °C; 1H NMR
(CDCl3, 400 MHz) 1.33 (t, 3H, J ) 7.1 Hz), 2.30 (s, 3H, J (Se,H)
) 14.6 Hz), 4.31 (q, 2H, J ) 7.1 Hz), 7.27 (dd, 2H, J ) 8.6, 2.2
Hz), 7.29 (t, 1H, J ) 7.7 Hz), 7.37 (t, 1H, J ) 7.7 Hz), 7.62
(dd, 2H, J ) 7.4, 1.2 Hz), 7.72 (dd, 1H, J ) 8.0, 1.0 Hz), 7.76
(dd, 1H, J ) 7.3, 1.2 Hz), 7.81 (dd, 1H, J ) 8.0, 1.4 Hz), 7.82
(dd, 1H, J ) 8.3, 2.2 Hz); 13C NMR (CDCl3, 100 MHz) 12.85
(1J ) 74.5 Hz, 5J ) 15.7 Hz), 14.29, 60.89, 126.03, 126.13,
127.99, 128.63, 130.14, 130.47, 130.80 (1J ) 12.5 Hz), 131.34,
132.37, 135.52, 135.91, 137.77, 142.80, 166.31; 77Se NMR
(CDCl3, 76 MHz) 442.4, 239.2 (4J (8Se,1Se) ) 294.7 Hz). Anal.
Calcd for C20H18Se2 O2: C, 53.59; H, 4.05. Found: C, 53.61;
H, 4.09.
1-(Met h ylsela n yl)-8-(p -n it r op h en ylsela n yl)n a p h t h a -
len e (2g). Following a method similar to that for 2b, 2g gave
81% yield as a white solid: mp 140.0-141.0 °C; 1H NMR
(CDCl3, 400 MHz) 2.29 (s, 3H, J (Se,H) ) 13.9 Hz), 7.23 (dd,
2H, J ) 9.0, 2.4 Hz), 7.37 (t, 1H, J ) 7.7 Hz), 7.40 (t, 1H, J )
7.7 Hz), 7.63 (dd, 1H, J ) 7.4, 1.0 Hz), 7.74 (dd, 1H, J ) 8.2,
1.0 Hz), 7.86 (dd, 1H, J ) 7.3, 1.4 Hz), 7.90 (dd, 1H, J ) 8.1,
1.2 Hz), 7.97 (dd, 2H, J ) 9.0, 2.4 Hz); 13C NMR (CDCl3, 100
MHz) 12.47 (1J ) 76.1 Hz, 5J ) 14.8 Hz), 123.92, 126.11,
126.37, 126.65, 127.81, 130.02 (1J ) 13.2 Hz), 130.67, 131.47,
132.42, 135.40, 136.00, 139.04 (1J ) 9.9 Hz), 146.11, 146.74;
77Se NMR (CDCl3, 76 MHz) 453.9, 240.1 (4J (8Se,1Se) ) 272.5
Hz). Anal. Calcd for C17H13Se2N1O2: C, 48.48; H, 3.11; N, 3.33.
Found: C, 48.66; H, 3.10; N, 3.27.
MO Ca lcu la tion s. Ab initio molecular orbital calculations
were performed on an Origin computer using the Gaussian
94 program with 6-311+G(2d,p) and 3-21G* basis sets at
B3LYP and/or HF levels.22 The σ values for H, C, and Se nuclei
were calculated using the NMR key word of the program, and
the natural charges (Qn) were calculated by the natural
population analysis.24
Bis{8-[p -(et h oxyca r b on yl)p h en ylsela n yl]n a p h t h yl}-
1,1′-d iselen id e (1f). Following a method similar to that for
1b, 1f gave 58% yield as a yellow solid: mp 167.0-169.5 °C;
1H NMR (CDCl3, 400 MHz) 1.34 (t, 6H, J ) 7.1 Hz), 4.32 (q,
4H, J ) 7.1 Hz),7.12 (t, 2H, J ) 7.8 Hz), 7.15 (dd, 2H, J ) 8.7,
1.9 Hz), 7.39 (t, 2H, J ) 7.6 Hz), 7.67 (dd, 2H, J ) 8.0, 0.9
Hz), 7.81 (dd, 4H, J ) 8.6, 1.9 Hz), 7.90 (dd, 2H, J ) 8.2, 1.1
Hz), 7.97 (dd, 2H, J ) 7.6, 1.2 Hz), 7.98 (dd, 2H, J ) 7.1, 1.4
Hz); 13C NMR (CDCl3, 100 MHz) 14.28, 60.83, 125.64, 125.93,
126.79, 128.27, 128.34, 128.78, 129.90, 130.13, 131.71, 132.07,
135.70, 136.36, 139.80, 142.50, 166.17; 77Se NMR (CDCl3, 76
MHz) 442.5, 530.2 (4J (8Se,1Se) ) 311.4 Hz). Anal. Calcd for
C
38H30Se4O4: C, 52.67; H, 3.49. Found: C, 52.84; H, 3.50.
B is [8-(p -n it r o p h e n y ls e la n y l)n a p h t h y l]-1,1′-d is e -
len id e (1g). Following a method similar to that for 1b, 1g
gave 56% yield as a yellow solid: mp 230.0-233.5 °C; 1H NMR
(CDCl3, 400 MHz) 7.14 (t, 2H, J ) 7.8 Hz), 7.16 (dd, 2H, J )
9.0, 2.5 Hz), 7.46 (t, 2H, J ) 7.7 Hz), 7.73 (dd, 2H, J ) 8.1, 1.0
Hz), 7.91 (dd, 2H, J ) 7.6, 1.1 Hz), 7.97 (dd, 4H, J ) 9.0, 2.2
Hz), 7.99 (dd, 2H, J ) 7.9, 1.3 Hz), 8.02 (dd, 2H, J ) 7.1, 1.4
Hz); 13C NMR (CDCl3, 100 MHz) 124.10, 124.42, 126.22,
126.97, 128.66, 128.84, 129.45, 132.11, 132.48, 135.55, 136.56,
140.34, 146.00, 146.15; 77Se NMR (CDCl3, 76 MHz) 456.1, 529.6
(4J (8Se,1Se) ) 294.1 Hz). Anal. Calcd for C32H20Se4N2O4: C,
47.31; H, 2.48; N, 3.45. Found: C, 47.52; H, 2.58; N, 3.35.
1-(Met h ylsela n yl)-8-(p -m et h oxyp h en ylsela n yl)n a p h -
th a len e (2b). The diselenide 1b was reduced by NaBH4 in
aqueous THF and then allowed to react with methyl iodide to
give 2b as a white solid: 91% yield; mp 86.0-87.0 °C; 1H NMR
(CDCl3, 400 MHz) 2.38 (s, 3H, J (Se,H) ) 13.4 Hz), 3.79 (s, 3H),
6.83 (dd, 2H, J ) 8.6, 2.2 Hz), 7.17 (t, 1H, J ) 7.7 Hz), 7.33 (t,
1H, J ) 7.7 Hz), 7.45 (dd, 2H, J ) 8.1, 2.2 Hz), 7.45 (dd, 1H,
J ) 6.8, 1.1 Hz), 7.64 (dd, 1H, J ) 8.1, 1.0 Hz), 7.70 (dd, 1H,
J ) 8.0, 1.1 Hz), 7.79 (dd, 1H, J ) 7.3, 1.1 Hz); 13C NMR
5
(CDCl3, 100 MHz) 13.90 (1J ) 71.2 Hz, J ) 15.7 Hz), 55.23,
115.17, 124.73, 125.70, 125.84, 128.26, 128.75, 131.25, 133.10,
133.50, 133.64, 134.94, 135.80, 136.47 (1J ) 11.5 Hz), 159.69;
77Se NMR (CDCl3, 76 MHz) 424.5, 233.1 (4J (8Se,1Se) ) 341.6
Hz). Anal. Calcd for C18H16Se2O1: C, 53.22; H, 3.97. Found:
C, 53.35; H, 3.90.
1-(Meth ylsela n yl)-8-(p-m eth ylp h en ylsela n yl)n a p h th a -
len e (2c). Following a method similar to that for 2b, 2c gave
89% yield as a white solid: mp 78.5-79.5 °C;. 1H NMR (CDCl3,
400 MHz) 2.32 (s, 3H), 2.36 (s, 3H, J (Se,H) ) 13.9 Hz), 7.08
(dd, 2H, J ) 7.8, 2.2 Hz), 7.20 (t, 1H, J ) 7.7 Hz), 7.34 (t, 1H,
J ) 7.8 Hz), 7.36 (dd, 2H, J ) 8.0, 2.2 Hz), 7.58(dd, 1H, J )
7.5, 1.3 Hz), 7.69 (dd, 1H, J ) 8.2, 1.1 Hz), 7.71 (dd, 1H, J )
8.4, 1.1 Hz), 7.76 (dd, 1H, J ) 7.4, 1.3 Hz); 13C NMR (CDCl3,
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research (C) (No. 09640635)
(W.N.) and on Priority Areas (A) (Nos. 09640635,
11120232, and 11166246) (W.N.) from the Ministry of
Education, Science, Sports and Culture, J apan.
5
100 MHz) 13.65 (1J ) 72.8 Hz, J ) 16.6 Hz), 21.27, 125.77,
125.88, 128.46, 128.77, 130.22, 131.24, 131.74, 132.22, 132.79,
133.86 (1J ) 11.6 Hz), 134.52, 135.17, 135.78, 137.53; 77Se
NMR (CDCl3, 76 MHz) 427.7, 234.5 (4J (8Se,1Se) ) 330.9 Hz).
Anal. Calcd for C18H16Se2: C, 55.40; H, 4.13. Found: C, 55.52;
H, 4.19.
Su p p or tin g In for m a tion Ava ila ble: Substituent effect
on δ(Ci) and δ(Se) of the p-YC6H4Se groups in 3-6 based on
ab initio MO calculations. This material is available free of
charge via the Internet at http://pubs.acs.org.
1-(Meth ylsela n yl)-8-(p-ch lor op h en ylsela n yl)n a p h th a -
len e (2d ). Following a method similar to that for 2b, 2d gave
87% yield as a white solid: mp 78.5-79.5 °C; 1H NMR (CDCl3,
400 MHz) 2.34 (s, 3H, J (Se,H) ) 13.9 Hz), 7.19 (dd, 2H, J )
J O9903860