Attractive interaction caused by the linear F···Se-C alignment in naphthalene peri positions

Article abstract of DOI:10.1021/ja974070q

The X-ray crystallographic analysis of 8-fluoro-1-(p- anisylselanyl)naphthalene (1) revealed that the F and Se atoms and the ipso- carbon of the p-anisyl group (C(An)) aligned linearly. The F atom and the Se- C(An) bond lay on the naphthyl plane: the nonb

Full text of DOI:10.1021/ja974070q

J. Am. Chem. Soc. 1998, 120, 3635-3640
3635
Attractive Interaction Caused by the Linear F‚‚‚Se-C Alignment in
Naphthalene Peri Positions
Waroˆ Nakanishi,*,† Satoko Hayashi,† Akira Sakaue,‡ Go Ono,† and Yuzo Kawada§
Contribution from the Department of Material Science and Chemistry, Faculty of Systems Engineering,
Wakayama UniVersity, Sakaedani, Wakayama 640-8510, Japan, Department of Chemistry, Faculty of
Education, Wakayama UniVersity, Sakaedani, Wakayama 640-8510, Japan, and Department of Chemistry,
Faculty of Science, Ibaraki UniVersity, Bunkyo, Mito, Ibaraki 310-8512, Japan
ReceiVed December 1, 1997
Abstract: The X-ray crystallographic analysis of 8-fluoro-1-(p-anisylselanyl)naphthalene (1) revealed that the
F and Se atoms and the ipso-carbon of the p-anisyl group (C(An)) aligned linearly. The F atom and the
Se-C(An) bond lay on the naphthyl plane: the nonbonded distance between F and Se atoms was 2.753(3) Å
and the FSeC(An) angle was 175.0(1)°. Ab initio MO calculations with the 6-311++G(3df,2pd) basis sets
performed on the model compound of 1, HF‚‚‚SeH2, where the aryl groups of 1 were replaced by hydrogens.
The calculations exhibited that the energy minimum was achieved when the F, Se, and C(An) atoms aligned
linearly. Charge transfer in the formation of HF‚‚‚SeH2 was suggested to occur from F to SeH2 on the basis
of natural population analysis, which supported the npx(F)-σ*(Se-C(An)) interaction.
Introduction
close proximity, together with the downfield shifts of the 77Se
NMR chemical shifts by the neighboring oxygen, but they are
controversial.
Nonbonded interactions between heteroatoms containing
group 16 elements in naphthalene 1,8-positions are of current
interest.1 We have also been interested in the nonbonded
interaction between a fluorine atom with a small size of the
valence orbitals and other heteroatoms in proximity in space,
such as a selenium atom. Lone pair-lone pair interactions have
been elucidated to play an important role in the nonbonded
spin-spin couplings between fluorine-fluorine,2 fluorine-
nitrogen,3 and selenium-selenium1d,g,4 atoms. Electrostatic5a
and charge-transfer5b mechanisms were proposed to explain the
attractive interactions between oxygen and selenium atoms in
In the course of our investigation on the intramolecular
interactions between naphthalene peri positions containing the
selenium atom(s) were prepared 8-fluoro-1-(p-anisylselanyl)-
naphthalene (1) and 8-fluoro-1-(methylselanyl)naphthalene (2).
† Department of Material Science and Chemistry, Faculty of Systems
Engineering, Wakayama University.
‡ Department of Chemistry, Faculty of Education, Wakayama University.
§ Department of Chemistry, Faculty of Science, Ibaraki University.
(1) (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. Glass, R. S.; Adamowicz, L.; Broeker, J. L. J. Am. Chem. Soc.
1991, 113, 1065. (b) Fujihara, H.; Ishitani, H.; Takaguchi, Y.; Furukawa,
N. Chem. Lett. 1995, 571. (c) Fujihara, H.; Yabe, M.; Chiu, J.-J.; Furukawa,
N. Tetrahedron Lett. 1991, 32, 4345. Furukawa, N.; Fujii, T.; Kimura, T.;
Fujihara, H. Chem. Lett. 1994, 1007. (d) Fujihara, H.; Saito, R.; Yabe, M.;
Furukawa, N. Chem. Lett. 1992, 1437. (e) Nakanishi, W. Chem. Lett. 1993,
2121. (f) Nakanishi, W.; Hayashi, S.; Toyota, S. J. Chem. Soc., Chem.
Commun. 1996, 371. (g) Nakanishi, W.; Hayashi, S.; Yamaguchi, H. Chem.
Lett. 1996, 947.
(2) (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.
The 77Se NMR chemical shifts of 1 and 2 were observed at
much downfield (ca. 90 ppm) relative to those of 1-(p-
anisylselanyl)naphthalene (3) and 1-(methylselanyl)naphthalene
(4), respectively.6 It is puzzling how the fluorine atom at the
8-position in 1 and 2 causes such large downfield shifts. The
selenium atom in 1 is expected to be electron-rich due to the
p-methoxyl group, which would be disadvantageous for the
electrostatic mechanism, since the mechanism requires the
positive charge development at the Se atom.5a It is very
interesting if the fluorine atom interacts attractively with the
selenium atom or the Se-C(An) bond (the bond between the
selenium atom and the ipso-carbon atom of the p-anisyl group)
in 1 by the through-space mechanism irrespective of its small
size of the valence orbitals. In this paper, we report the structure
of 1 studied by the X-ray crystallographic analysis and by the
ab initio molecular orbital calculations, exhibiting the linear
(3) Mallory, F. B.; Luzik, E. D., Jr.; 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.
(4) Johannsen, I.; Eggert, H. J. Am. Chem. Soc. 1984, 106, 1240.
Johannsen, 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.
(5) (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.
(6) The 77Se chemical shifts of 1, 2, 3, and 4 were δ 440.9, 250.4, 354.2,
and 159.0, respectively.
S0002-7863(97)04070-5 CCC: $15.00 © 1998 American Chemical Society
Published on Web 04/02/1998

3636 J. Am. Chem. Soc., Vol. 120, No. 15, 1998
Nakanishi et al.
Table 1. Selected Crystal Data and Structure Refinement for 1
in 1 are replaced by hydrogens in the model compound and Ha
and Hb denote the hydrogens near HF and far from HF,
respectively (Scheme 1). The 6-311++G(3df,2pd) basis sets
of the Gaussian 9411 program at HF and MP2 levels were
employed for the calculations. Calculations were carried out
for the two structures. For structure a, all atoms are placed on
the xz plane and the Se atom is placed at the origin. The angle
θ1 is defined as the sum of the angles between F-Se bond and
the y axis and between y axis and Se-Hb bond (namely, θ1 is
equal to the torsional angle HHaSeHb), which is therefore fixed
at 180.0°. The HFSe, FSeHb (θ2; θ2 is defined as 360.0 -
( FSeHa + HaSeHb)° when θ1 is not 180.0°), and HaSeHb
in HF‚‚‚SeHaHb are fixed at 100.0°, 185.0°, and 100.8°,
respectively. The r(F,Se) value is fixed at 2.753 Å and r(F,H),
r(Se,Ha), and r(Se,Hb) are optimized (Scheme 1a). For structure
b, all atoms are placed on the xz plane except for Hb and the Se
atom is placed at the origin. The HFSe, FSeHa, and the
torsional angle H-F-Se-Ha in HF‚‚‚SeHaHb are fixed at 90.0°,
90.0°, and 0.0°, respectively, while θ1 and θ2 (and therefore
HaSeHb) are optimized. The r(F,Se) value is fixed at 2.753
Å, and r(F,H), r(Se,Ha), and r(Se,Hb) are optimized (Scheme
1b). Calculations on HF and SeH2 were also performed
similarly for convenience of comparison.
formula
fw, g mol-1
cryst syst
space group
color
a, Å
b, Å
C17H13FOSe
331.25
triclinic
P1h (No. 2)
colorless
13.649(7)
14.068(8)
8.184(5)
93.06(5)
100.20(5)
68.21(4)
1436(1)
1.532
c, Å
R, deg
â, deg
γ, deg
V, Å3
D
calcd, g cm-3
Z
4
θ range for data collected, deg
data
2.0-27.5
4292
parameter
R
Rw
362
0.045
0.044
GOF
1.4291
alignment of the F‚‚‚Se-C(An) atoms with the analysis of the
charge-transfer5b mechanism for the interaction.
Results and Discussion
The results of the MO calculations on structure a at the HF
and MP2 levels with the 6-311++G(3df,2pd) basis sets are
shown in Table 3. The MO calculations were performed with
variously fixed θ1 for structure b at the MP2/6-311++G(3df,2pd)
level, and two energy minima existed. The one corresponds to
structure b with θ1 ) 180.0°,12,13 and the other to structure b
with θ1 ) 65.4°. The energy of the adduct was plotted against
θ1, and the results are shown in Figure 2. Structure b with θ1
) 180.0° was shown to be more stable than structure b with θ1
) 65.4° by 0.0073 au (19 kJ mol-1). The results, together with
those at the HF level, are also shown in Table 3. Structure b
with θ1 ) 65.4° brought out the importance of the linear F‚‚‚Se-
Hb interaction in structure b with θ1 ) 180.0°. The bond
distances, especially r(Se,Hb), of structure b with θ1 ) 180.0°
became longer and the bond angle of the adduct became smaller
relative to the corresponding values of the free components
whereas those of structure b with θ1 ) 65.4° were close to those
of the components. Both of the r(Se,Ha) and r(Se,Hb) values
of structure b with θ1 ) 180.0° increased, whereas only r(Se,Hb)
was increased in structure a in the formation of the adduct. The
results of MO calculations support that the linear alignment of
F‚‚‚Se-C(An) atoms is not due to the crystal packing effect
but the results of the energy lowering effect caused by the linear
alignment of the F atom and the Se-C(An) bond.
Single crystals of 1 were obtained via slow evaporation of a
hexane solution and one of suitable crystals was subjected to
X-ray crystallographic analysis. The crystallographic data are
collected in Table 1. There are two types of structures of 1 in
the crystal (structure A and structure B). The selected inter-
atomic distances, angles, and torsional angles of structure A
and structure B are shown in Table 2. One of the structures of
1 (structure A) is shown in Figure 1.7 For structure A, the
planarity of the naphthyl and anisyl planes was very good. The
anisyl plane was perpendicular to the naphthyl plane (the
torsional angle C(1)-Se-C(11)-C(16) being 89.0(4)°). The
fluorine atom and the Se-C(An) bond lay on the naphthyl
plane: the torsional angles of F-C(9)-C(10)-C(1), Se-C(1)-
C(10)-C(9), and C(11)-Se-C(1)-C(10) were 1.2(6)°, -0.1(5)°,
and -179.2(3)°, respectively. The F-Se-C(An) angle in the
naphthyl plane ( FSeC(An)) was 175.0(1)°. The nonbonded
distance between F and Se atoms (r(F,Se)) was 2.753(3) Å,
which was shorter than the sum of the van der Waals radii8 of
F and Se atoms (3.35 Å) by 0.60 Å.
Why do the fluorine, selenium, and carbon atoms align
linearly? Since the π-orbitals in naphthalene ring, together with
p-type lone pairs of F and Se atoms, are perpendicular to those
of the anisyl ring, the interaction between the two π-systems
would be negligible. Two types of interactions are possible:
one is the interaction of the π-framework of naphthalene ring
cooperated by the p-type orbitals of fluorine and selenium atoms
and the other is the n(F)-σ*(Se-C(An)) type interaction, which
is strongly suggested by the linear alignment of the F‚‚‚Se-
C(An) atoms in 1.9,10
(11) Gaussian 94, ReVision D.4; Frisch, M. J.; Trucks, G. W.; Schlegel,
H. B.; Gill, P. M. W.; Johnson, 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.
(12) In the actual calculations on structure b, the angles θ1 and θ2 were
optimized to be 180.11 and 179.16°, respectively, at the HF level and 180.03
and 181.12°, respectively, at the MP2 level. However, precisely the same
results, such as bond lengths and angles, and energies were obtained at
both levels when the calculations were performed with θ1 of structure b
fixed at 180.00°. The potential surface must be almost flat near θ1 ) 180°.
(13) The energy of the adduct was evaluated to be larger than the sum
of those for HF and H2Se. The results exhibit that the adduct is destabilized
relative to the free components. The fluoro and selanyl groups cannot exist
this close if the two groups are not joined by the naphthalene 1,8-positions.
The n(F)-σ*(Se-C(An)) type interaction is examined first.
Ab initio molecular orbital calculations were performed on the
model compound of 1, HF‚‚‚SeHaHb, to elucidate the nature of
the nonbonded interaction between the atoms: the aryl groups
(7) Although the discussion is focused on structure A, it is also valid on
structure B.
(8) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
University Press: Ithaca, New York, 1960; Chapter 7. See also: Bondi, A.
J. Phys. Chem. 1964, 68, 441.
(9) Rosenfield, R. E., Jr.; Parthasarathy, R.; Dunitz, J. D. J. Am. Chem.
Soc. 1977, 99, 4860.
(10) Ramasubbu, N.; Parthasarathy, R. Phosphorus Sulfur 1987, 31, 221.

Linear F‚‚‚Se-C Alignment in Naphthalene
J. Am. Chem. Soc., Vol. 120, No. 15, 1998 3637
Table 2. Selected Interatomic Distances (Å), Angles (deg), and Torsional Angles (deg) of 1
structure A
structure B
Interatomic Distances
SeA-C1A
SeA-C11A
FA-C9A
1.928(4)
1.918(4)
1.352(5)
2.753(3)
1.422(5)
1.412(5)
SeB-C1B
SeB-C11B
FB-C9B
1.932(4)
1.906(4)
1.346(6)
2.744(3)
1.427(5)
1.409(6)
SeA-FA
SeB-FB
C1A-C10A
C9A-C10A
C1B-C10B
C9B-C10B
Angles
C1A-SeA-C11A
SeA-C1A-C10A
FA-C9A-C10A
C1A-C10A-C9A
FA-SeA-C11A
100.8(2)
C1B-SeB-C11B
SeB-C1B-C10B
FB-C9B-C10B
C1B-C10B-C9B
FB-SeB-C11B
99.6(2)
120.7(3)
118.7(4)
125.6(4)
164.3(1)
120.5(3)
119.1(3)
125.9(3)
175.0(1)
Torsional Angles
C11A-SeA-C1A-C10A
C1A-SeA-C11A-C16A
SeA-C1A-C10A-C9A
FA-C9A-C10A-C1A
-179.2(3)
89.0(4)
-0.1(5)
1.2(6)
C11B-SeB-C1B-C10B
C1B-SeB-C11B-C16B
SeB-C1B-C10B-C9B
FB-C9B-C10B-C1B
-162.8(3)
-110.5(4)
-0.9(6)
-3.7(6)
the npx(F)-σ*(Se-Hb) interaction16 as well as the charge
transfer from HF to SeH2.
Natural charges (Qn) were computed by natural population
analysis17 for structure a and structure b and the corresponding
structures of SeH2 and HF with the 6-311++G(3df,2pd) basis
sets of both the HF and MP2 levels. The results are collected
in Table 3. The fluorine atom became substantially more
positive when the adducts of structure a and structure b with
θ1 ) 180.0° were formed, which showed that the fluorine atom
acted as an electron donor in this interaction. The change
transfer shown in the Qn can be explained by assuming the
two processes: (i) the charge transfer from F to SeH2 and (ii)
the charge transfer from npx(F) to σ*(Se-Hb) resulting from
the linear F‚‚‚Se-Hb interaction. If the linear F‚‚‚Se-Hb
interaction can be recognized as the unsymmetrical three
center-four electron (3c-4e) F‚‚‚Se-Hb interaction, the F, Se,
and Hb atoms are expected to be more negative, positive, and
negative, respectively.18 The positive and negative charges
developed on the Se and Hb atoms in the formation of the adduct
are well explained by the 3c-4e model. The positive and
negative charge development at the F and Ha atoms must show
the contribution of the charge transfer from F to SeH2 (see also
Figure 3). On the other hand, the electrons at the F and Se
atoms of structure b with θ1 ) 65.4° moved to hydrogens. The
lone pair-lone pair repulsive interaction of the F and Se atoms
must expel electrons to hydrogens, mainly to Ha. The Se-Hb
bond no longer play an important role, and the HF molecule
does not act as an electron donor in the adduct.
Figure 1. ORTEP drawing of 1 (structure A).
Scheme 1
Molecular orbitals were drawn using the MacSpartan Plus
program14 with the 3-21G(*) basis sets for structure a and the
corresponding structures of HF and SeH2: the single point
calculations were performed on the structures that were partially
optimized at the MP2/6-311++G(3df,2pd) level, as shown in
Table 3. Figure 3 shows the diagram in the formation of
HF‚‚‚SeH2, exemplified by structure a, together with the npx(F)
orbital of HF and the 4B2, 9A1, 10A1, and 5B2 orbitals of SeH2.
The 4B1 orbital of SeH2, which is HOMO consisted of the 4pz
orbital of the Se atom, is not shown in Figure 3, since the orbital
does not interact with the npx(F) due to its symmetry.15
Although the molecular orbitals of SeH2 do not interact with
each other due to the orthogonality, if the molecule is far from
others, they begin to interact with each other, as well as with
the npx(F) orbital when HF comes close to SeH2.16 While the
energy levels of 4B2 and 9A1 orbitals of SeH2 must be
considerably higher than that of the npx(F) of HF, the three
orbitals become to interact to make new molecular orbitals in
the formation of HF‚‚‚SeH2. The npx(F) orbital also interacts
with the unoccupied orbitals such as 10A1 and 5B2 of SeH2 by
the same reason. The interaction with the unoccupied orbitals
must be important since it stabilizes the bond of the adduct and
modifies the new orbitals of the adduct to some extent. Such
orbital interaction in HF‚‚‚SeH2 results in the contribution of
Parthasarathy et al. have suggested that there are two types
of directional preferences of nonbonded atomic contacts with
divalent sulfur, Y-S-Z.9 Type I contacts with electrophiles
which have S‚‚‚X directions in YZS‚‚‚X where n-electrons of
sulfides are located and type II contacts with nucleophiles
tending to lie along the extension of one of sulfur’s bond.
Electrophiles should interact preferentially with HOMO of the
sulfur lone pair and nucleophiles with LUMO of the σ*(S-Y)
or σ*(S-Z) orbital. Similar directional preferences of non-
(17) NBO Version 3.1; Glendening, E. D.; Reed, A. E.; Carpenter, J.
E.; Weinhold, F.; Gaussian Link 607.
(18) (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.
(14) MacSpartan Plus Ver. 1.0, Hehre, H. J. Wavefunction, Inc.
(15) The results for structure b with θ1 ) 180.0° and the corresponding
molecules were essentially the same as those exhibited in Figure 3.
(16) Inagaki, S.; Fujimoto, H.; Fukui, K. J. Am. Chem. Soc. 1976, 98,
4054.

3638 J. Am. Chem. Soc., Vol. 120, No. 15, 1998
Nakanishi et al.
Table 3. Structures, Energies, and Natural Charges (Qn) in HF‚‚‚SeH2, HF, and SeH2 Calculated with the 6-311++G(3df,2pd) Basis Setsa
r(F,H) r(Se,Ha) r(Se,Hb)
(Å) (Å) (Å)
θ1
(deg)
HaSeHb
(deg)
level
E (au)
Qn(F)
Qn(H)
Qn(Se)
Qn(Ha)
Qn(Hb)
Structure a
b,c
b,c
HF‚‚‚SeH2
HF
HF
HF
-2501.0175 0.8979
-100.0577 0.8973
-2400.9668
1.4509 1.4559 180.0d 100.8d
-0.5517
-0.5581
0.5581 -0.0772
0.5581
0.0346
0.0572
0.0361
0.0572
HF
SeH2
∆
1.4515 1.4515
0.0070 0.0006 -0.0006 0.0044
100.8d
0.0
-0.1144
0.0372 -0.0226 -0.0211
0.0064
0.0000
HF‚‚‚SeH2
MP2 -2501.4645 0.9184
MP2 -100.3321 0.9172
MP2 -2401.1363
0.0039 0.0012 -0.0006 0.0049
1.4562 1.4617 180.0d 100.8d
-0.5556
-0.5617
0.5620 -0.0781
0.5617
0.0350
0.0367
HF
SeH2
∆
1.4568 1.4568
100.8d
0.0
-0.1161
0.0380 -0.0230 -0.0213
0.0580
0.0580
0.0061
0.0003
Structure b
e
e
e
HF‚‚‚SeH2
HF
HF
HF
-2501.0177 0.8979
-100.0577 0.8973
-2400.9684
1.4563 1.4577 180.0f
90.8g,h -0.5507
-0.5581
0.5573 -0.0784
0.5581
0.0364
0.0532
0.0355
0.0532
HF
SeH2
∆
1.4530 1.4530
0.0033 0.0047
93.2g
-0.1064
0.0280 -0.0168 -0.0177
0.0084 0.0006
-2.4
0.0074 -0.0008
HF‚‚‚SeH2
MP2 -2501.4658 0.9184
MP2 -100.3321 0.9172
MP2 -2401.1385
0.0048 0.0012
1.4622 1.4643 180.0f
88.9g,i
-0.5547
-0.5617
0.5614 -0.0787
0.5617
0.0366
0.0354
HF
SeH2
∆
1.4591 1.4591
0.0031 0.0052
91.3g
-0.1072
0.0285 -0.0170 -0.0182
0.0536
0.0536
-2.4
0.0070 -0.0003
HF‚‚‚SeH2
∆
MP2 -2501.4585 0.9176
1.4604 1.4559
0.0013 0.0008
65.4g
91.7g
0.4
-0.5610
0.0007 -0.0011
0.5606 -0.0843
0.0354
0.0493
0.0121 0.0004
0.0229 -0.0182 -0.0043
c
e
a r(F,Se) fixed at 2.753 Å. b θ2 fixed at 185.0°.
HFSe fixed at 100.0°. d Fixed value.
HFSe fixed at 90.0°. f See ref 12. g Optimized value.
h θ2 optimized to be 179.2°. i θ2 optimized to be 181.1°.
Figure 2. Plot of energy against θ1 in structure b.
bonded atomic contacts have also shown with divalent sele-
nium.10 The linear alignment of F, Se, and C(An) atoms in 1
apparently belongs to type II with the central atom of Se. The
F atom as the type II in F‚‚‚Se-C(An) linear alignment should
be recognized as a nucleophile and must act as an electron donor
accompanied by the σ*(Se-C(An)) orbital as an acceptor in
the close proximity. The MO calculations, containing the
natural population analysis, support the n(F)-σ*(Se-C(An))
interaction in 1.
Contributions of π-orbitals were also examined. 8-Fluoro-
1-naphthaleneselenole (5), together with 1-naphthaleneselenole
(6) and 1-fluoronaphthalene (7), was calculated with the
6-311+G(d,p) basis sets at the HF level. The fluorine atom
Figure 3. Diagram in the formation of HF‚‚‚SeH2 from HF and SeH2
(see text).
values in 5 were estimated to be 93.7°, 166.4°, and 2.779 Å,
respectively. Natural charges (Qn) were also computed, and
the results are shown in Table 4. The Qn values of F, Se, and
H(Se) became more positive, positive, and negative, respec-
tively, relative to those of the corresponding atoms in 6 and 7,
which was the same trend calculated on the models shown in
Table 3. The structure of 5 was also optimized using the
MacSpartan Plus program with the 3-21G(*) basis sets. The
and the Se-H bond were optimized to be placed on the plane
of the naphthalene ring. The CSeH, FSeH, and r(F,Se)

Linear F‚‚‚Se-C Alignment in Naphthalene
J. Am. Chem. Soc., Vol. 120, No. 15, 1998 3639
2, together with some novel reactions20 correlated with the
formation of the compounds, is in progress.
Table 4. Natural Charges (Qn) in 5 - 7 Calculated with
6-311+G(d,p) Basis Sets at the HF Level
compd
Qn(F)
Qn(Se)
Qn(H)
Experimental Section
5
6
7
-0.3922
0.2086
0.1560
0.0252
0.0489
Chemicals were used without further purification unless otherwise
noted. Solvents were purified by standard methods. Melting points
were recorded on a YANAKO Model MP and uncorrected. 1H, 13C,
and 77Se NMR spectra were recorded on a JEOL Lambda 400
spectrometer operating at 399.7, 100.4, and 76.2 MHz, respectively.
Coupling constants (J) are given in hertz. 1-(Methylselanyl)naphthalene
(4) was prepared according to the method in the literature.1c
-0.3950
∆Qn
0.0028
0.0526
-0.0237
8-Fluoro-1-(p-anisylselanyl)naphthalene (1). To an ethereal solu-
tion of 8-(fluoronaphthyl)magnesium bromide, resulting from 8-bromo-
1-fluoronaphthalene21,22 and magnesium, was added an ethereal solution
of di(p-anisyl) diselenide under argon atmosphere. After usual workup,
was obtained 1. Recrystallization from hexane gave colorless prisms:
1
yield 67%; mp 83-84.5 °C; H NMR (399.65 MHz, CDCl3) δ 3.86
(s, 3H), 6.89 (dd, J ) 1.0, 7.8, 1H), 6.96 (d, J ) 9.4, 2H), 7.15 (t, J )
7.8, 1H), 7.17 (ddd, J ) 1.0, 7.8, 13.2, 1H), 7.37 (dt, J ) 5.4, 8.1,
1H), 7.56 (dd, J ) 1.0, 7.8, 1H), 7.58 (dd, J ) 1.0, 7.8, 1H), 7.64 (d,
J ) 9.4, 2H). Anal. Calcd for C17H13FOSe: C, 62.00; H, 3.96.
Found: C, 62.21; H, 4.05.
Figure 4. HOMO of 8-fluoro-1-naphthaleneselenole (5).
8-Fluoro-1-(methylselanyl)naphthalene (2). Sodium 8-fluoro-1-
naphthaleneselenate was allowed to react with methyl iodide in a THF-
water mixed solvent under argon atmosphere to give 2. After
chromatography on silica gel with hexane as an eluent, recrystallization
from hexane gave colorless prisms: yield 93%; mp 59-60 °C; 1H NMR
(399.65 MHz, CDCl3) δ 2.38 (s, 3H), 7.14 (ddd, J ) 1.2, 7.8, 13.2,
1H), 7.30 (br d, J ) 7.3, 1H), 7.36 (t, J ) 7.8, 1H), 7.36 (dt, J ) 4.8,
7.8, 1H), 7.59 (dd, J ) 0.9, 8.3, 1H), 7.62 (dd, J ) 1.0, 8.3, 1H). Anal.
Calcd for C11H9FSe: C, 55.25; H, 3.79. Found: C, 55.48; H, 3.99.
Sodium 8-fluoro-1-naphthaleneselenate was prepared from bis(8-
fluoronaphthyl)-1,1′-diselenide.23 The diselenide was obtained in the
reaction of 8-bromo-1-fluoronaphthalene,21,22 magnesium, and selenium
powder in diethyl ether under argon atmosphere followed by oxidation
with air and recrystallized from hexane.
HOMO of 5 is shown in Figure 4. The p-orbitals of F and Se
atoms contribute to the π-type HOMO. The npx(F)-σ*(Se-
Hb) type interaction was shown to contribute to the lower energy
orbitals.
The nonbonded r(F,Se) of 2.753(3) Å was shorter than the
sum of the van der Waals radii8 of F and Se atoms by 0.60 Å
(∆rv(F,Se) ) 0.60 Å). The nonbonded Se‚‚‚Se distances in
1-(methylselanyl)-8-(phenylselanyl)naphthalene (8)19 and bis-
[8-(phenylselanyl)naphthyl] diselenide (9)1f are 3.070(1) and
3.053(1) Å, respectively, on average. Since the sum of the van
1-(p-Anisylselanyl)naphthalene (3). To an ethereal solution of
naphthylmagnesium bromide, resulting from 1-bromonaphthalene and
magnesium, was added an ethereal solution of di(p-anisyl) diselenide
under argon atmosphere. After usual workup, was obtained 3.
Recrystallization from hexane gave colorless prisms: yield 62%; mp
100.0-101.0 °C; 1H NMR (399.65 MHz, CDCl3) δ 3.78 (s, 3H), 6.82
(d, J ) 8.9, 2H), 7.30 (dd, J ) 7.3, 8.2, 1H), 7.45 (d, J ) 8.9, 2H),
7.46-7.55 (m, 3H), 7.75 (d, J ) 8.2, 1H), 7.83 (dd, J ) 2.2, 7.2, 1H),
8.28 (ddd, J ) 0.9, 2.0, 7.6, 1H). Anal. Calcd for C17H14OSe: C,
65.18; H, 4.50. Found: C, 65.23; H, 4.46.
der Waals radii of the two Se atoms is 4.00 Å, the nonbonded
Se‚‚‚Se distances in 8 and 9 are shorter than the value by 0.93-
0.95 Å (∆rv(Se,Se) ) 0.93-0.95 Å). Indeed the r(F,Se) must
be mostly determined by the peri positions where the two atoms
are joined, but the fluorine atom in 1 might contribute to
decrease the distance to some extent since the ∆rv(F,Se) in 1 is
larger than a half of the ∆rv(Se,Se) in 8 and 9. The observed
r(F,Se) value would be consistent with the attractive interaction
caused by the linear n(F)-σ*(Se-C(An)) alignment in 1,
although the energy of structure b with θ1 ) 180.0° is evaluated
to be higher than the free components by 0.0048 au (13 kJ
mol-1) at the MP2/6-311++G(3df,2pd) level.13
X-ray Structural Determination of 1. The colorless single crystals
of 1 were grown by slow evaporation of a hexane solution at room
temperature. A crystal of dimensions 0.60 × 0.30 × 0.30 mm3 was
measured on a Rigaku AFC7R diffractometer with graphite-monochro-
mated Mo KR radiation (λ ) 0.710 69 Å). The structure was solved
by direct methods using SHELXS-8624 and was refined by block
diagonal least-squares using UNICS III.25 The function minimized was
2
Σw(|Fo| - |Fc|)2, where w ) 1/[σ2(|Fo|) + 0.001|Fo| ]. The non-
hydrogen atoms were refined anisotropically. All hydrogen atoms were
(20) We have encountered a facile reductive C-F bond cleavage in the
reaction of sodium 8-fluoro-1-naphthaleneselenate with p-(methoxyben-
zene)diazonium chloride, which yields not 1 but 3. The C-F bond cleavage
must be, we believe, the reflection of the nonbonded interaction between F
and Se atoms.
(21) Adcock, W.; Matthews, D. G.; Rizvi, S. Q. A. Aust. J. Chem. 1971,
24, 1829.
(22) The compound was prepared according to the literature and obtained
the same results for elemental analyses.21 The observed value for carbon
was ca. 1% larger than that of the calculated one while that for hydrogen
was satisfactory.
(23) It was also difficult to purify the compound similarly to the case of
ref 22. Further investigation containing the C-F bond cleavage20 is in
progress, and the results will be reported elsewhere.
(24) Sheldrick, G. M. Acta Crystallogr. Sect. A 1990, A46, 467.
(25) Sakurai, T.; Kobayashi, K. Rep. Inst. Phys. Chem. Res. 1979, 55,
69.
Four bond couplings between F and Se atoms (4J(F,Se)) of 1
and 2 were observed to be 285.0 and 276.7 Hz, respectively,
while 4J(F,F) in 1,8-difluoronaphthalene2b and 4J(Se,Se) in
1-(methylselanyl)-8-(phenylselanyl)naphthalene1g were reported
5
to be 58.8 and 322.4 Hz, respectively. The J(F,C) values in
the F‚‚‚Se-C bonds of 1 and 2 were detected to be 18.2 and
14.9 Hz, respectively. The role of the linear F‚‚‚Se-C
alignment on the downfield shifts of the 77Se NMR chemical
shifts and the large J values containing the Se nucleus in 1 and
(19) Nakanishi, W.; Hayashi, S.; Toyota, S. Unpublished results.

3640 J. Am. Chem. Soc., Vol. 120, No. 15, 1998
Nakanishi et al.
located on a Fourier difference map and not refined. The final cycle
of block diagonal least-squares refinement was based on 4292 observed
reflections (I > 3.00σ(F)) and 362 variable parameters and converged
with unweighted and weighed agreement factors to give R ) 0.045
and Rw ) 0.044 for independent observed reflections.
(W.N.) from Ministry of Education, Science, Sports and Culture,
Japan. The authors thank Dr. Tsunehisa Okuno for refining the
X-ray crystallographic data.
MO Calculations. Ab initio molecular orbital calculations were
performed on a Power Challenge L computer using the Gaussian 94
program with the 6-311++G(3df,2pd) and 6-311+G(d,p) basis sets at
the HF and/or MP2 levels. The molecular orbitals in Figures 3 and 4
were drawn by a Power Macintosh 8500/180 personal computer using
MacSpartan Plus program (Ver. 1.0) with 3-21G(*) basis sets.
Supporting Information Available: Tables of crystal data
and structure refinement, atomic coordinates for non-hydrogen
atoms, together with the bond lengths, bond angles, and tosional
angles for 1 and geometries and energies for structure b with
variously fixed angles θ1, together with the optimized ones for
θ1, calculated with 6-311++G(3df,2pd) basis sets at the MP2
level (11 pages, print/PDF). See any current masthead page
for ordering information and Web access instructions.
Acknowledgment. This paper is dedicated to Professor
Michinori Oˆ ki on the occasion of his 70th birthday. This work
was partly supported by a Grant-in-Aid for Scientific Research
(09640635) (W.N.) and that on Priority Areas (09239232)
JA974070Q