H/D isotope effect on 77Se NMR chemical shifts in 8-Methyl-1-(arylselanyl) naphthalenes and related selenides: Nonbonded C-H-Se through-space versus through-bond mechanisms

Article abstract of DOI:10.1080/10426500902947807

77Se NMR chemical shifts of methyl-d3 derivatives of 8-methyl-1- (phenylselanyl) naphthalene (1) and 8-methyl-1-(p-anisylselanyl)naphthalene (2) are observed 0.25 and 0.20 ppm upfield from 1 and 2, respectively. The observations must be the reflection of the nonbonded interactions of the C-H-Se 3c-4e type in 1 and 2. The mechanism is elucidated by means of crystallographic and theoretical investigations. The nonbonded distance between Se and CMe (2.989A) is observed to be shorter than the sum of the van der Waals radii of the two by 0.91A in 2. 1 and 2 may be in equilibrium between conformers A and B in solution, where Se-Ci is perpendicular to the naphthyl plane in A and it is on the plane in B. Natural bond orbital (NBO) analysis on 1 revealed that the nonbonded np(Se)-σ *(CH) interaction contributes in A, whereas nonbonded ns(Se)-σ *(C-H) and double (C-H)-σ *(Se-C) interactions operate in B.

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Phosphorus, Sulfur, and Silicon
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H/D Isotope Effect on 77Se NMR
Chemical Shifts in 8-Methyl-1-
(arylselanyl)naphthalenes and
Related Selenides: Nonbonded
C─H—Se Through-Space Versus
Through-Bond Mechanisms
Satoko Hayashi a , Kentaro Yamane a & Waro
Nakanishi a
a Department of Material Science and Chemistry,
Faculty of Systems Engineering , Wakayama
University , Wakayama, Japan
Published online: 06 Jun 2009.
To cite this article: Satoko Hayashi , Kentaro Yamane & Waro Nakanishi (2009) H/D
Isotope Effect on 77Se NMR Chemical Shifts in 8-Methyl-1-(arylselanyl)naphthalenes
and Related Selenides: Nonbonded C─H—Se Through-Space Versus Through-Bond
Mechanisms, Phosphorus, Sulfur, and Silicon and the Related Elements, 184:6,
1481-1495, DOI: 10.1080/10426500902947807
To link to this article: http://dx.doi.org/10.1080/10426500902947807
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Phosphorus, Sulfur, and Silicon, 184:1481–1495, 2009
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500902947807
H/D Isotope Effect on 77Se NMR Chemical Shifts in
8-Methyl-1-(arylselanyl)naphthalenes and Related
Selenides: Nonbonded C H—Se Through-Space Versus
Through-Bond Mechanisms
Satoko Hayashi, Kentaro Yamane, and Waro Nakanishi
Department of Material Science and Chemistry, Faculty of Systems
Engineering, Wakayama University, Wakayama, Japan
77Se NMR chemical shifts of methyl-d3 derivatives of 8-methyl-1-(phenylselanyl)
naphthalene (1) and 8-methyl-1-(p-anisylselanyl)naphthalene (2) are observed 0.25
and 0.20 ppm upfield from 1 and 2, respectively. The observations must be the re-
flection of the nonbonded interactions of the C H—Se 3c–4e type in 1 and 2. The
mechanism is elucidated by means of crystallographic and theoretical investiga-
˚
tions. The nonbonded distance between Se and CMe (2.989 A) is observed to be
˚
shorter than the sum of the van der Waals radii of the two by 0.91 A in 2. 1 and
2 may be in equilibrium between conformers A and B in solution, where Se Ci
is perpendicular to the naphthyl plane in A and it is on the plane in B. Natural
bond orbital (NBO) analysis on 1 revealed that the nonbonded np(Se)—σ ∗(C H)
interaction contributes in A, whereas nonbonded ns(Se)—σ ∗(C H) and double σ
(C H)—σ ∗(Se–C) interactions operate in B.
Keywords Ab initio calculations; H/D isotopic effect; natural bond orbital analysis;
NMR; nonbonded C H—Se interaction; structures
INTRODUCTION
Nonbonded interactions containing group 16 elements are of current
interest.1−3 Naphthalene 1,8-positions serve as a good system to study
the interactions. Lone pair orbitals of heteroatoms play an important
role in the nonbonded interactions. They have much effect on the energy
Received 7 January 2008; accepted 3 February 2008.
Dedicated to Professor Marian Mikolajczyk, CBMiM PAN in Lo´dz´, Poland, on the
ꢀ
ꢀ
occasion of his 70th birthday.
This work was partially supported by a Grant-in-Aid for Scientific Research (Nos.
16550038 and 19550041) from the Ministry of Education, Culture, Sports, Science, and
Technology, Japan.
Address correspondence to Waro Nakanishi, Department of Material Science and
Chemistry, Faculty of Systems Engineering, Wakayama University, 930 Sakaedani,
Wakayama 640-8510, Japan. E-mail: nakanisi@sys.wakayma-u.ac.jp
1481

1482
S. Hayashi et al.
∗
FIGURE 1 Compounds I and the np(G)—σ (Se C) interaction.
of the system and the NMR parameters, such as chemical shifts and
the nuclear spin–spin couplings containing the atoms.1d,g,2,3 We have
demonstrated the attractive nonbonded linear G—Se C interactions in
8-G-1-(arylselanyl)naphthalenes (I), where G are Br and Cl and even
F.2a,e p-Type lone pair orbitals of halogens [np(G)] and the anti-bonding
∗
orbitals of the Se C bonds (σ (Se C)∗) play an important role in the
attractive interactions of the np(G)—σ (Se C) form (IA) (Figure 1).
We have also been interested in the nonbonded C H—Se
and/or H—Se C interactions in relation to the nonbonded lin-
ear G—Se C interactions in I. Although the G—Se C inter-
actions for G of halogens are well explained by hypervalent
np(G)—σ ∗(Se C) 3c–4e type interactions, such contribution would
be small for
G
=
Me. Nevertheless, large downfield shifts
in δ (Se) are detected for 8-methyl-1-(phenylselanyl)-naphthalene
(1) and 8-methyl-1-(p-anisylselanyl)naphthalene (2), relative to 1-
(phenylselanyl)naphthalene (3)4 and 1-(p-anisylselanyl)naphthalene
(4),4 respectively (Figure 2). The values amounted to 81–92 ppm. What
happens in 77Se NMR chemical shifts [δ (Se)], when selanyl and methyl
groups are placed proximity in space? The results must come from the
large steric effect of the methyl group on the neighboring selenium
atom by the through-space interaction in 1 and 2.
The nonbonded interactions between the methyl and selanyl groups
are investigated by means of the H/D isotope effect on δ (Se), employing
naphthalene 1,8-positions in 1–4 and benzene 1,2-positions in o-tolyl
phenyl selenide (5) and diphenyl selenide (6) (Figure 2). The mechanism
of the H/D isotope effect is demonstrated to be pure through-space for
1 and 2, whereas that of 6 is through-bond. The difference between
the through-space and the through-bond mechanisms must supply the
information on the nonbonded C H—Se and/or H—Se C interactions.
The structure of 2 is determined by the X-ray crystallographic anal-
ysis to clarify the structural environments in the H/D isotope effect.
Structures of 1 and 2 are optimized employing the 6-311+G(2d,p) basis
sets of the Gaussian 03 program5 at the density functional theory (DFT:

77
H/D Isotope Effect on Se NMR
1483
FIGURE 2 Compounds with which the H/D isotope effect examined.
B3LYP).6,7 Natural bond orbital (NBO) analysis8,9 is carried out for the
plausible structures of 1, A, and B (see Scheme 1). The observations
are explained based on the observed and the calculated structures.
Here, we report the nature of the C H—Se and/or H—Se C inter-
actions based on the H/D isotope effect, together with the results of QC
calculations, employing 1–6.
SCHEME 1 Plausible structures of 1 and 2.

1484
S. Hayashi et al.
FIGURE 3 Structure of 2, showing the numbering scheme (thermal ellipsoids
are shown at 30% probability levels).
RESULTS AND DISCUSSION
Structure of 1-Methyl-8-(p-anisylselanyl)naphthalene (2)
The structure of 2 was determined by the X-ray crystallographic anal-
ysis, whereas that of 1 was not due to its oily nature. Single crystals
of 2 were obtained via slow evaporation of a hexane solution and one
of suitable crystals was subjected to the analysis. Table I shows the
crystallographic data. Figure 3 shows the structure of 210 and Table II
collects the selected interatomic distances, angles, and torsional angles,
necessary for the discussion.
The planarity of the naphthyl and anisyl planes is very good. The ani-
syl plane is almost perpendicular to the naphthyl plane, the torsional
angle of C1-Se-C11-C12 being 86.7(4) degrees. The methyl carbon and
the Se C11 bond lay on the naphthyl plane: the torsional angles of
TABLE I Crystallographic Data for 2
Formula
C18H16OSe
Z
)
8
Mol wt
T (K)
327.28
292(1)
Dcalcd (g cm−3
F(000)
1.455
1328
4313
3591
Cryst. syst.
Space group
monoclinic
C2/c (#15)
14.033(4)
11.903(5)
17.970(4)
95.54(2)
2987(1)
no. of rflns collected
no. of ind rflns
no. of data/restraints/params
goodness of fit, F2
R1, wR2
˚
a (A)
1829/0/181
1.45
0.043, 0.051
[I > 1.5σ (I)]
0.38 to –0.29
˚
b (A)
˚
c (A)
β (◦)−3
−3
˚
˚
V (A
)
largest diff peak (e A
)

77
H/D Isotope Effect on Se NMR
1485
TABLE II Selected Interatomic Distances, Angles, and Torsional
Angles of 2a
˚
Interatomic distances (A)
Se-C1
1.933 (4)
2.989 (5)
Se-C11
C9-C18
1.914 (5)
1.504 (7)
Se-C18
Angles (◦)
Se-C1-C2
117.6 (3)
120.8 (4)
101.8 (2)
125.0 (4)
Se-C1-C10
Se-C11-C16
C11-Se-C18
122.1 (3)
120.1 (4)
175.1 (2)
Se-C11-C12
C1-Se-C11
C10-C9-C18
Torsional angles (◦)
C10-C1-Se-C11
Se-C1-C10-C9
173.7 (4)
0.8 (6)
C1-Se-C11-C12
C1-C10-C9-C18
86.7 (4)
2.3 (7)
aThe atomic numbering scheme for 2 is defined in Figure 1.
C1-C10-C9-C18, Se-C1-C10-C9, and C10-C1-Se-C11 are 2.3(7), 0.8(6),
and 173.7(4) degrees, respectively. The nonbonded distance between Se
˚
and C18 atoms [r(Se, CMe)] is 2.989(5) A, which is shorter than the sum
of the van der Waals radii11 of Me group and Se atom by 0.91 A [ꢀrv(Se,
˚
˚
CMe) = 0.91 A]. Since the methyl group is not spherical, the interpreta-
tion of the van der Waals radii must be considered carefully in this case
(the gear effect).12 The methyl carbon (CMe), selenium, and ipso carbon
(Ci) of the p-anisyl group in 2 align linearly: the C11-Se-C18 angle is
175.1(2) degrees. The linear alignment in 2 would be mainly controlled
by the np(Se)–π (Nap) conjugation.
H/D Isotope Effect on δ (Se)
The 77Se NMR spectrum was measured for 1 in chloroform-d at an
ambient NMR probe temperature of 25◦C. The resolution of 77Se NMR
spectra was 0.7 Hz (0.01 ppm) measured at 76 MHz. The signal was
observed at δ (Se) = 452.57. A new signal appeared at the 0.25 ppm
upfield from that of 1 when the CD3 derivative of 1 [1 (Me-d3)] was
added to the solution. The new signal grew up as the addition of 1
(Me-d3). The half value widths (ν 1/2) of the 77Se NMR signals in 1 and
1 (Me-d3) are 2.8 and 5.7 Hz, respectively. The H/D isotope effect of 1
was –0.25 ppm [= δ (Se: 1 (Me-d3)) – δ (Se: 1)]. The H/D isotope effect of
2 was also measured. The effect was –0.20 ppm. The ν
values for 2
1/2
and 2 (Me-d3) are 2.8 and 6.2 Hz, respectively. Figure 4 shows the 77Se
NMR spectra recorded at a 1:1 mixture of 2 and 2 (Me-d3). The H/D

1486
S. Hayashi et al.
FIGURE 4 77Se NMR spectra recorded at a 1:1 mixture of 2 and 2 (Me-d3).
isotope effect was similarly measured for 3, 5, and 6. Table III collects
the results, together with the ν 1/2 values.
Before discussion of the H/D isotope effect on δ (Se) in the naphtha-
lene system, that of the benzene system is discussed, first.
As shown in Table III, the H/D isotope effect on δ (Se) of 6 is 0.93
ppm. The ν
values of 6 and 6 (H(2)–d) are both 3.8 Hz. The same
1/2
ν
values show that the nuclear spin–spin coupling between Se and
1/2
D(2) in 6 (H(2)–d) is very small, so is that between Se and D(2) in 6.
The H/D isotope effects were reported to be –7.0 and –14.0 ppm for
HDSe and D2Se relative to H2Se, respectively.13 It is –7.0 ppm per
D. The effect is large since D is joined directly to Se in place of the
Se–H bond in these cases. The effect of –1.68 ppm was reported for
2-deuterioselenophene relative to selenophene14 and the –3.78 ppm for
TABLE III H/D Isotope Effects on 77Se NMR Chemical Shifts and the
Half-Value Widths of 1–3, 5, and 6
δ (Se: d)
δ (Se)
ꢀδ (Se)a
ν
1/2(Se: d) (Hz)
ν
1/2(Se) (Hz)
ꢀν1/2b (Hz)
1
2
3
5
6
452.32
435.07
361.10
382.55
422.36
452.57
435.27
361.02
382.66
423.29
–0.25
–0.20
0.08
–0.11
–0.93
5.7
6.2
3.6
3.4
3.8
2.8
2.8
3.2
3.4
3.8
2.9
3.4
0.4
0.0
0.0
aδ (Se: with d) – δ (Se).
bν 1/2(Se: with d) – ν 1/2(Se).

77
H/D Isotope Effect on Se NMR
1487
PhSeCD2Ph from PhSeCH2Ph (–1.89 ppm per D).15,16 The effect in
benzyl phenyl selenide is close to that in selenophene. The H/D isotope
effect of –0.93 ppm in 6 is about a half of those in selenophene and
benzyl phenyl selenide. The smaller effect in 6 must be the reflection
of one bond longer between Se and H(D) in 6 relative to selenophene
and benzyl phenyl selenide. The mechanism of the H/D isotope effect
in hydrogen selenide is through-bond and those in selenophene and
benzyl phenyl selenide must be mainly through-bond.17 Consequently,
the mechanism in 6 should also be through-bond in the analogy with
above cases.
The H/D isotope effect of –0.11 ppm is observed for 5, which is much
smaller than that in 6. The value observed for 3 is 0.08 ppm. The mag-
nitudes of the effect in 3 and 5 are very close to each other, although the
signs are different. The ν 1/2 values for δ (Se) of 3, 5, and the deuterated
compounds were almost the same (3.2–3.8 Hz). The magnitude of the
H/D isotope effect decreases as the bond number between Se and H(D)
in question increases.18 Therefore, the H/D isotope effect in 3–6 can be
explained by the through-bond mechanism. Indeed, the through-space
mechanism could operate in 3 and 5, but the contributions seem small.
The H/D isotope effects of –0.25 ppm in 1 and –0.20 ppm in 2 are
substantially larger than those observed in 3 and 5, respectively, in
magnitude. The ν 1/2 values of 5.7 Hz in 1 (Me-d3) and 6.2 Hz in 2 (Me-
d3) are also substantially larger than those of 2.8 Hz in 1 and 2. It is
difficult to explain such a large H/D isotope effect by the through-bond
mechanism. The effect in 1 and 2 must be smaller than that in 3 and 5,
if only through-bond mechanism operates: The numbers of the bonds
between the atoms in 1 and 2 are five, whereas they are three in 3 and
5. Namely, the through-space mechanism is demonstrated to operate
in the H/D isotope effect in 1 and 2. The nonbonded nuclear spin–spin
couplings in 1 and 2 can be similarly explained by the through-space
mechanism.
Why is the H/D isotope effect in 1 and 2 negative? The effect would
arise from the very slight difference between the r(Se, DMe) and r(Se,
HMe) in 1 and 2. The potential surfaces around the atoms must be
essentially the same with each other in 1 and 2. The mass of deu-
terium is twice of that of hydrogen. Therefore, the zero-point energy
for a C–D bond is about 0.71 (≈ 2−1/2) times larger than that of the
C H bond, which results in a slightly shorter bond distance for C–D
relative to C H, in the average.19 Namely, the C–D bonds in 1 (Me-
d3) and 2 (Me-d3) would be slightly shorter than the C H bonds in 1
and 2, respectively, which will decrease slightly the steric conjunction20
around Se in 1 (Me-d3) and 2 (Me-d3), relative to 1 and 2, respectively.

1488
S. Hayashi et al.
This consideration supports the conclusion that the negative H/D iso-
tope effect in 1 and 2 arises from the through-space mechanism, where
the steric compression between Me-d3 and Se in 1 (Me-d3) and 2 (Me-
d3) is slightly released, relative to 1 and 2, respectively. Although the
H/D isotope effect in 1 and 2 is small, the intrinsic steric compression
between Se and Me must be very large judging from the ꢀr(Se, CMe
)
˚
value of 0.91 A in 2. The ꢀr(Se, CMe) values affect on of δ (Se) in 1 and
2 from 3 and 4, respectively. The conclusion in the H/D isotope effect is
in accordance with ꢀδ (Se) in 1 and 2.
The through-space mechanism is well demonstrated for the negative
H/D isotope effect in 1 and 2. How does the effect originate through
the C H—Se and/or H—Se C interactions? Quantum chemical (QC)
calculations are performed on 1 and 2, containing the NBO analysis, to
elucidate the nature of the nonbonded interaction.
QC Calculations on 1 and 2
QC calculations were performed on 1 and 2 by the B3LYP/6-
311+G(2d,p) method. Scheme 1 shows plausible structures, A, B, and
B’ for 1 and 2, where Se Ci is perpendicular to the naphthyl plane in A
and it is on the plane in B. A and B are stable, whereas B’ is expected
to be a transition state.10
Calculations are performed on 1 (A), 1 (B), 1 (B’), 2 (A), and 2 (B).
Table IV shows the results, containing the relative energies.21 While
the energies of 1 (A) and 1 (B) are very close with each other, 1 (B’)
is less stable than 1 (B) by 15.2 kJ mol−1. On the other hand, 2 (B)
is predicted to be substantially stable than 2 (A) (E(2 (B)) – E(2 (A))
= –7.1 kJ mol−1). The global minimum of 2 (B) well reproduced the
structure of 2 determined by the X-ray crystallographic analysis. 2 (B)
is expected to contribute much in the solution.
TABLE IV Results of QC Calculations on 1 and 2 with
the B3LYP/6-311+G(2d,p) Method
E (au)
ꢀE (kJ mol−1
)
1 (A)
1 (B)
1 (B’)
2 (A)
2 (B)a
–3057.9673
–3057.9683
–3057.9625
–3172.5261
–3172.5288
0.0
–2.6
15.2
0.0
–7.1
a2 (B) is optimized even if starting from 2 (B’).

77
H/D Isotope Effect on Se NMR
1489
SCHEME 2 Nonbonded interactions in 1, contributing to A and B.
Charge-transfer interactions from donor NBO(i) to acceptor NBO(j)
can be evaluated through the second order perturbation theory analysis
in the NBO basis. They are evaluated by Equation 1, where E(2) is the
second order perturbation energy, qi is the donor orbital occupancy,
F(i, j) is the off-diagonal NBO Fock matrix element, and (εi – εj ) is the
energy difference between donor NBO(i) and acceptor NBO(j).
E(2) = ꢀEij = qiF(i, j)2/(E(j) − E(i))
(1)
Natural bond orbital (NBO) analysis is carried out on 1 (A) and1 (B).
Table V shows the results of NBO analysis, and Scheme 2 illustrates the
results.21 The np(Se)—σ ∗(C H) interaction contributes 4.5 kJ mol−1 for
1 (A). In the case of 1 (B), the ns(Se)—σ ∗(C H) inte∗raction contributes
3.8 kJ mol−1, together with the double σ(C H)—σ (Se C) type inter-
actions by 8.4 kJ mol−1 (4.2 kJ mol−1 for each). Why is the contribution
∗
of the nonbonded ns(Se)—σ (∗C H) interaction (3.8 kJ mol−1) in 1 (B)
close to that of the np(Se)—σ (C H) type (4.5 kJ mol−1) in 1 (A)? The
nonbonded distance between Se and CMe must be an important factor
to control the values. The r(Se, CMe) values optimized for 1 (A) and 1
˚
(B) are 3.211 and 3.025 A, respectively. The former is longer than the
˚
latter by 0.186 A, which makes the contributions almost equal.
Are there some differences between the nonbonded interactions de-
scribed by C H—Se and H—Se C? The image of the nonbonded C H—
Se interaction may be close to the np(Se)—σ ∗(C H) and ns(Se)—
σ
∗(C H) interactions, whereas the H—Se C interaction would be

1490
S. Hayashi et al.
TABLE V Results of NBO Analysis for 1 with the
B3LYP/6-311+G(2d,p) Methoda
Acceptor
E(2)d
E(j)–E(i)e
F(i, j)f
(au)
Donor NBO(i)b
NBO(j)c
(kJ mol−1
)
(au)
g
g
˚
1 (A): r(Se, CMe) = 3.211 A
np(Se)
σ∗ (CMe–Hc)
4.5
0.63
0.024
˚
1 (B): r(Se, CMe) = 3.025 A
σ (CMe–Ha)
σ (CMe–Hb)
ns(Se)
σ∗ (Se Ci)
σ∗ (Se Ci)
σ∗ (CMe–Hc)
4.2
4.2
3.8
0.63
0.63
1.12
0.023
0.023
0.029
aSecond order perturbation of Fock matrix (threshold being 2.1 kJ mol−1).21
bDonor orbitals. cAcceptor orbitals.
dThe values are the estimated strengths of the donor–acceptor interactions. The
stabilization energy associated with these interactions is evaluated by Equation 1 in
the text.
eEnergy difference between donor NBO(i) and acceptor NBO(j).
f The element of the Fock (or Kohn-Sham) matrix describing the donor–acceptor
interaction.
gCalculated values.
∗
understood by the σ (C H)—σ (Se C) type. The results of the NBO
analysis show that the nonbonded n(Se)—σ ∗(C H) interaction operates
in both A and B, whereas the nonbonded σ(C H)—σ ∗(Se C) type inter-
∗
action contributes only in B. The contribution of σ (C H)—σ (Se C)
would be negligible, which is less than the threshold value of 2.1 kJ
mol−1
.
CONCLUSION
It is elucidated how the C H bonds, with very stable σ (C H) and high
∗
energy σ (C H) orbitals, interact with neighboring groups, such as
n(Se) and/or σ ∗(Se C) orbitals of the ArSe group, employing the naph-
thalene 1,8-positions of 1 and 2. The structure of 2 is determined by
the X-ray crystallographic analysis. The nonbonded distance between
˚
Se and CMe in 2 is 2.989 A, which is shorter than the sum of the van
˚
der Waals radii of the atoms by 0.91 A. The δ (Se) values of methyl-d3
derivatives of 1 and 2 are observed 0.25 and 0.20 ppm upfield from 1
and 2, respectively, in chloroform-d. The H/D isotope effect must occur
through the C H—Se and/or H—Se C interactions. The mechanism
for the nonbonded interactions is eluc∗idated based on the NOB analysis
of 1. While the nonbonded np(Se)—σ (C H) interaction contributes in

77
H/D Isotope Effect on Se NMR
1491
∗
∗
A, both nonbonded ns(Se)—σ (C H) and double σ (C H)—σ (Se C)
interactions operate in B.
The effect of nonbonded Se—CMe interactions on the NMR parame-
ters of 1 and 2 are also of interest. Investigations to clarify the origin
of the downfield shifts by the methyl group at the 8-position in 1-
(arylselanyl)naphthalenes are in progress. The results will be reported
elsewhere.
EXPERIMENTAL
Chemicals were used without further purification unless otherwise
noted. Solvents were purified by standard methods. Melting points
were uncorrected. Column chromatography was performed on silica
1
gel and basic alumina for the purification of compounds. H, 13C, and
77Se NMR spectra were measured at 400, 100, and 76 MHz, respec-
1
tively. The H, 13C, and 77Se chemical shifts are given in ppm relative
to those of internal CHCl3 slightly contaminated in CDCl3 solutions,
CDCl3 as the solvent, and external MeSeMe, respectively. The resolu-
tion is 0.7 Hz (0.01 ppm) for 77Se NMR spectra under the conditions of
measurements.
8-(Methyl)-1-(phenylselanyl)naphthalene (1)
To an ether solution of a Grignard reagent prepared from 1-bromo-
8-metylnaphthalene and magnesium, an ether solution of diphenyl
diselenide22 was added under argon atmosphere. After the usual
workup, the crude product was chromatographed on silica gel contain-
ing basic alumina and gave 1 as pale yellow oil in 88% yield; 1H NMR
(CDCl3, 400 MHz) δ : 3.14 (s, 3H), 7.20 (t, 1H, J = 7.8 Hz), 7.31–7.39
(m, 5H), 7.45–7.50 (m, 2H), 7.52 (dd, 1H, J = 7.3 and 1.2 Hz), 7.70–7.75
(m, 2H); 13C NMR (CDCl3, 100 MHz) δ : 25.6, 125.3, 125.5, 127.5, 128.0,
129.1, 129.6, 129.8, 130.2, 131.6, 132.9, 133.5, 133.6, 133.8, 135.8; 77Se
NMR (CDCl3, 76 MHz) δ : 452.57. Anal. Calcd. For C17H14Se1: C, 68.69;
H, 4.75. Found: C, 68.53; H, 4.77.
8-(Methyl)-1-(p-anisylselanyl)naphthalene (2)
Following a method similar to that for 1, 2 gave 88% yield as colorless
1
prisms: mp 67–68◦C. H NMR (CDCl3, 400 MHz) δ : 3.02 (s, 3H), 3.66
(s, 3H), 6.76 (dd, 2H, J = 8.7 and 2.5 Hz), 6.97 (t, 1H, J = 7.7 Hz), 7.09
(dd, 1H, J = 7.4 and 1.3 Hz), 7.15 (dd, 1H, J = 7.3 and 1.9 Hz), 7.18 (t,
1H, J = 7.3 Hz), 7.39 (dd, 2H, J = 8.7 and 2.9 Hz), 7.47 (dd, 1H, J =

1492
S. Hayashi et al.
8.0 and 1.2 Hz), 7.52 (dd, 1H, J = 7.7 and 1.8 Hz); 13C NMR (CDCl3,
100 MHz) δ : 25.5 (J = 35.8 Hz) , 55.2, 115.5, 121.2, 125.3, 125.4, 127.7,
127.8, 128.3, 129.7, 132.8, 133.0, 135.7, 135.9, 137.5 (J = 12.0 Hz); 77Se
NMR (CDCl3, 76 MHz) δ : 435.27. Anal. Calcd. For C18H16O1Se1: C,
66.06; H, 4.93. Found: C, 65.81; H, 4.83.
1-(Phenylselanyl)naphthalene (3)
Following a method similar to that for 1, 3 gave 82% yield as pale
1
yellow oil; H NMR (CDCl3, 400 MHz) δ : 6.82 (dd, 2H, J = 8.9 and
2.1 Hz), 7.15–7.22 (m, 3H), 7.32–7.37 (m, 2H), 7.37 (t, 1H, J = 8.3 Hz),
7.48–7.53 (m, 2H), 7.76 (dd, 1H, J = 7.1 and 1.2 Hz), 7.82–7.87 (m,
2H), 8.32–8.35 (m, 1H); 13C NMR (CDCl3, 100 MHz) δ : 125.9, 126.2,
126.7, 126.8, 127.5 (J = 10.8 Hz), 128.5, 129.5, 129.2, 129.3, 131.6 (J =
12.4 Hz), 131.6, 133.7 (J = 9.1 Hz), 134.0, 134.0; 77Se NMR (CDCl3, 76
MHz) δ : 361.02. Anal. Calcd. For C16H12Se1: C, 67.85; H, 4.27. Found:
C, 67.93; H, 4.25.
1-(p-Anisylselanyl)naphthalene (4) was prepared by the same
method in the literature.2a Colorless prisms: 82% yield, mp 100–101◦C.
2-Tolyl Phenyl Selenide (5)
Following a method similar to that for 1, 5 gave 84% yield as colorless
1
oil; H NMR (CDCl3, 400 MHz) δ : 2.40 (s, 3H), 7.06 (br.t, 1H, J = 7.4
and 1.4 Hz), 7.19 (t, 1H, J = 7.5 and 1.2 Hz), 7.21–7.29 (m, 4H), 7.33 (dd,
1H, J = 7.6 and 1.2 Hz), 7.38–7.42 (m, 2H); 13C NMR (CDCl3, 100 MHz)
δ : 22.3 (J = 10.5 Hz), 126.7, 127.1, 127.7, 129.3, 130.2, 130.7, 131.7,
132.7 (J = 10.9 Hz), 133.6, 139.8 (J = 11.4 Hz); 77Se NMR (CDCl3, 76
MHz) δ : 382.66. Anal. Calcd. For C13H12Se1: C, 63.17; H, 4.89. Found:
C, 63.02; H, 4.92.
Diphenyl selenide (6) was prepared according to the literature.23
The deuterium compounds, 1 (Me-d3), 2 (Me-d3), and 5 (Me-d3) were
prepared in the reaction of the corresponding aryl magnesium bro-
mides with dimethyl sulfate-d6, and 3 (H(8)–d) and 6 (H(2)–d) were
prepared similarly in the reaction of the magnesium bromides with
D2O.
X-Ray Structural Determination
The colorless single crystals of 2 were grown by slow evaporation of
a hexane solution at room temperature. A crystal of dimensions 0.30
× 0.30 × 0.30 mm3 was measured on a Rigaku AFC5R diffractometer

77
H/D Isotope Effect on Se NMR
1493
˚
with graphite monochromated Mo-Kα radiation (λ = 0.71069 A) and a
rotating anode generator. The structure was solved by direct methods
using SAPI9124 and expanded using Fourier techniques, DIRDIF94.25
The non-hydrogen atoms were refined anisotropically. Hydrogen atoms
were included but not refined. The final cycle of full-matrix least-
squares refinement was based on 1829 observed reflections (I > 1.50σ
(I)) and 181. Variable parameters and converged with unweighted and
weighted agreement factors of R = (ꢁ||Fo| –|Fc||)/ꢁ| Fo| and ω R = {ꢁω
1/2
(|Fo| –|Fc|)2/ꢁω F2o} were used to give R = 0.043 and ω R = 0.051 for
independent observed reflections. For least squares, the function mini-
2
mized was ꢁω (|Fo| –|Fc|)2, where ω = (σc2| Fo| + p2| Fo| /4)−1. Additional
crystal and analysis data are listed in Table I.
CCDC-627281 contains the supplementary crystallographic data
for this article. This data can be obtained free of charge form
The Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data request/cif.
COMPUTATIONAL
QC calculations were performed on 1 and 2 with 6-311+G(2d,p) ba-
sis sets of the Gaussian 03 program.5 Calculations are performed at
the density functional theory (DFT) level of the Becke three parameter
hybrid functional combined with the Lee–Yang–Parr correlation func-
tional (B3LYP).6,7 NBO analysis8,9 is also carried out for the plausible
structures of 1, which are type A and type B and type B’ (see Scheme 1).
REFERENCES AND NOTES
[1] (a) R. S. Glass, S. W. Andruski, J. L. Broeker, H. Firouzabadi, L. K. Steffen, and G. S.
Wilson, J. Am. Chem. Soc., 111, 4036–4045 (1989); R. S. Glass, L. Adamowicz, and
J. L. Broeker, J. Am. Chem. Soc., 113, 1065–1072 (1991); (b) H. Fujihara, H. Ishi-
tani, Y. Takaguchi, and N. Furukawa, Chem. Lett., 571–572 (1995); (c) H. Fujihara,
M. Yabe, J.-J. Chiu, and N. Furukawa, Tetrahedron Lett., 32, 4345–4348 (1991); N.
Furukawa, T. Fujii, T. Kimura, and H. Fujihara, Chem. Lett., 1007–1010 (1994); (d)
H. Fujihara, R. Saito, M. Yabe, and N. Furukawa, Chem. Lett., 1437–1440 (1992);
(e) W. Nakanishi, Chem. Lett., 2121–2122 (1993); (f) W. Nakanishi, S. Hayashi, and
S. Toyota, Chem. Comm., 371–372 (1996); (g) W. Nakanishi, S. Hayashi, and H. Ya-
maguchi, Chem. Lett., 947–948 (1996); (h) W. Nakanishi, S. Hayashi, and S. Toyota,
J. Org. Chem., 63, 8790–8800 (1998); (i) M. C. Aragoni, M. Arca, F. Demartin, F.
A. Devillanova, A. Garau, P. Grimaldi, F. Isaia, F. Lelj, V. Lippolis, and G. Verani,
Eur. J. Inorg. Chem., 2363–2368 (2004); (j) M. Iwaoka, H. Komatsu, T. Katsuda, and
S. Tomoda, J. Am. Chem. Soc., 126, 5309–5317 (2004); (k) G. Mugesh, A. Panda,
H. B. Singh, N. S. Punekar, and R. J. Butcher, J. Am. Chem. Soc., 123, 839–850
(2001); (l) Chemistry of Hypervalent Compounds, K.-y. Akiba (Ed.) (Wiley-VCH,

1494
S. Hayashi et al.
New York, 1999); (m) W. Nakanishi, Hypervalent chalcogen compounds, In Hand-
book of Chalcogen Chemistry: New Perspectives in Sulfur, Selenium and Tellurium,
F. A. Devillanova (Ed.), Royal Society of Chemistry (Cambridge, UK, 2006), Chapter
10.3.1, pp. 644–668.
[2] (a) W. Nakanishi, S. Hayashi, A. Sakaue, G. Ono, and Y. Kawada, J. Am. Chem. Soc.,
120, 3635–3640 (1998); (b) W. Nakanishi and S. Hayashi, J. Phys. Chem. A, 103,
6074–6081 (1999); (c) S. Hayashi and W. Nakanishi, J. Org. Chem., 64, 6688–6696
(1999); (d) W. Nakanishi, S. Hayashi, and T. Uehara, J. Phys. Chem. A, 103, 9906–
9912 (1999); (e) W. Nakanishi and S. Hayashi, J. Org. Chem., 67, 38–48 (2002); (f)
W. Nakanishi, S. Hayashi, D. Shimizu, and M. Hada, Chem. Eur. J., 12, 3829–3846
(2006); (g) S. Hayashi and W. Nakanishi, Bioinorganic Chemistry and Applications,
DOI 10.1155/BCA/2006/79327 (2006).
[3] I. Johannsen and H. Eggert, J. Am. Chem. Soc., 106, 1240–1243 (1984); I. Jo-
hannsen, H. Eggert, S. Gronowitz, and A.-B. Ho¨rnfeldt, Chemica Scripta, 27, 359–
361 (1987); H. Fujihara, H. Mima, T. Erata, and N. Furukawa, J. Am. Chem. Soc.,
114, 3117–3118 (1992).
[4] W. Nakanishi, S. Hayashi, and T. Uehara, Eur. J. Org. Chem., 3933–3943 (2001).
[5] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheese-
man, J. A. Montgomery, T. Vreven, Jr. K. N. Kudin, J. C. Burant, J. M. Millam, S. S.
Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A.
Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa,
M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox,
H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R.
E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y.
Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski,
S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck,
K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J.
Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L.
Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Chal-
lacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, C. Gonzalez, and J. A.
Pople, Gaussian 03, revision B.05; Gaussian, Inc., Pittsburgh, PA (2003).
[6] C. Lee, W. Yang, and R. G. Parr, Phys. Rev., B37, 785–789 (1988).
[7] A. D. Becke, Phys. Rev., A38, 3098 (1988); A. D. Becke, J. Chem. Phys., 98, 5648–5652
(1993).
[8] A. E. Reed, R. B. Weinstock, F. Weinhold, J. Chem. Phys., 83, 735–746 (1985); J. E.
Carpenter, and F. Weinhold, J. Mol. Struct. (THEOCHEM), 169, 41–62 (1988).
[9] NBO Ver. 3.1, E. D. Glendening, A. E. Reed, J. E. Carpenter, F. Weinhold. Theoretical
Chemistry Institute, University of Wisconsin, Madison, WI.
[10] The structure of 2 (B’) would be assigned if the hydrogen atoms of the methyl group
were positioned automatically. However, 2 (B) is reasonably determined by the X-
ray crystallographic analysis, when the H atoms are positioned at those higher
electron densities around the CMe atom. R-values for 2 (B) are smaller than those
for 2 (B’). 2 (B) is optimized even if started from 2 (B’) in the QC calculations.
[11] A. Bondi, J. Phys. Chem., 68, 441–451 (1964). See also, for Me and Ph, L. Pauling,
The Nature of the Chemical Bond, 3rd ed. (Cornell University Press, Ithaca, NY,
1960), Chapter 7.
[12] D. Gust and K. Mislow, J. Am. Chem. Soc., 95, 1535–1547 (1973); K. Mislow, Acc.
Chem. Res., 9, 26–33 (1976); H. Iwamura and K. Mislow, Acc. Chem. Res., 21, 175–
182 (1988); G. Yamamoto, Pure Appl. Chem., 62, 569–574 (1990); G. Yamamoto, K.
Inoue, H. Higuchi, M. Yanebayashi, Y. Nabeta, J. Ojima, Bull. Chem. Soc. Jpn., 71,
1241–1248 (1998).

77
H/D Isotope Effect on Se NMR
1495
[13] H. J. Jakobsen, A. J. Zozulin, P. D. Ellis, and J. D. Odom, J. Magn. Reson., 38,
219–227 (1980).
[14] H. J. Jakobsen and R. S. Hansen, J. Magn. Reson., 30, 397–399 (1978).
[15] M. Iwaoka, H. Komatsu, and S. Tomoda, Bull. Chem. Soc. Jpn., 69, 1825–1828
(1996).
[16] The isotope effect has been studied for 6H,12H-dibenzo[b, f ][1, 5]diselenocin and
concluded that the nonbonded C H—Se interaction would be attractive based on
the results.20 However, the through-space H/D isotope effect seems not well sepa-
rated from the through-bond one in the system.
[17] For the 12C/13C isotope effect on the δ (Se) of selenides, see W. Gombler, J. Am.
Chem. Soc., 104, 6616–6620 (1982), and for the selenium isotope effect on the δ (Se)
of organic selenium compounds see, W. Gombler, J. Magn. Reson., 53, 69–75 (1983).
[18] The bond number is an important factor to understand the H/D isotope effect on
δ (Se) if the through-bond mechanism operates. The role of the bond number is
established as the α-, β-, γ-, and δ-effects in δ (Se). The α-, β-, γ-, and δ-effects are
27
57,26 120, –37, and 3 ppm, respectively, in the series of PhSeCnH2n+1
.
The γ-
effect is upfield shifts and the ε-effect is negligibly small.28 The H/D isotope effect
in 6 may correspond to the γ-effect and those in 5 and 3 to the δ-effect. The H/D
isotope effect of 1 and 2 must be accounted for by the ε-effect if the mechanism were
through-bond.
[19] F. H. Westheimer, Chem. Rev., 61, 265–273 (1961). See also, Mechanism and Theory
in Organic Chemistry, T. H. Lowry and K. S. Richardson (Eds.), 2nd Ed. (Harper
and Row Publishers, New York, 1981), p. 205.
[20] D. M. Grant and B. V. Cheney, J. Am. Chem. Soc., 89, 5315–5318 (1967).
[21] Total energies (E) and MO energies [E(i)] are shown in atomic unit (au) and energy
differences (ꢀE) are in kJ mol−1, as usual. The second order perturbation energies
of the NBO analysis [E(2)] are also given in kJ mol−1, although they are calculated
in kcal mol−1
.
[22] G. A. Kalabin, D. F. Kushnarev, L. M. Kataeva, L. V. Kashurnikova, and R. I.
Vinokurova, Zh. Org. Khim., 14, 2478–2483 (1978).
[23] B. Greenberg, E. S. Gould, and W. Burlant, J. Am. Chem. Soc., 78, 4028–4029 (1956).
[24] H.-F. Fan. Structure analysis program with intelligent control (Rigaku Corporation,
Tokyo, Japan, 1991).
[25] P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, R. de Gelder, R. Is-
rael, and J. M. M. Smits, The DIRDIF-94 program system, technical report of the
crystallography laboratory (University of Nijmegen, the Netherlands, 1994).
[26] The δ (Se) values of MeSeH, MeSeMe, and MeSeEt are reported to be –130, 0, and
108, respectively: the α-effect is much larger than the case of ArSeR.27
[27] The Chemistry of Organic Selenium and Tellurium Compounds, S. Patai, Z. Rap-
poport (Eds.), (Wiley, New York, 1986), Vol. 1, Chapter 6.
[28] The [δ(ASe), δ(BSe)] values were reported to be (392.7, 372.5) and (389.1, 370.7) for
PhASeBSeC4H9–n and PhASeBSeC5H11–n, respectively; see, J. A. Anderson, J. D.
Odom, and A. Zozulin, J. Organometallics, 3, 1458–1465 (1984).