Synthetic and structural studies of 1, 8-chalcogen naphthalene derivatives

Article abstract of DOI:10.1002/chem.200903523

Four novel 1,8-disubstituted naphthalene derivatives 4-7 that contain chalcogen atoms occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular distortion due to noncovalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X-ray data for 4-7 was compared to the series of known 1, 8-bis(phenylchalcogeno) naphthalenes 1-3, which were themselves prepared from novel synthetic routes. A general increase in the E-E' distance was ob-served for molecules containing bulkier atoms at the peri positions. The decreased S...S distance from phenyl-1 and ethyl-4 analogues is ascribed to a weaker chalcogen lone pair-lone pair repulsion acting in the ethyl analogue due to the presence of two equatorial S(naphthyl) ring conformations. Two novel pen-substituted naphthalene sulfoxides of 1, Nap(O=SPh)(SPh) 8 and Nap(O=SPh)₂ 9, which contain different valence states of sulfur, were pre-pared and fully characterised by using X-ray crystallography and multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular structures were analysed by using naphthalene ring torsions, peri-atom displacement, splay angle magnitude, S...S interactions, aromatic ring orientations and quasi-linear O=S...S arrangements. The axial S(naphthyl) rings in 8 and 9 are unfavourable for S-S contacts due to stronger chalcogen lone pair-lone pair repulsion. Although quasi-linear O=S...S alignments suggest attractive interaction is conceivable, analysis of the B3LYP wavefunctions affords no evidence for direct bonding interactions between the S atoms.

Full text of DOI:10.1002/chem.200903523

FULL PAPER
DOI: 10.1002/chem.200903523
Synthetic and Structural Studies of 1,8-Chalcogen Naphthalene Derivatives
Fergus R. Knight, Amy L. Fuller, Michael Bꢀhl, Alexandra M. Z. Slawin, and
J. Derek Woollins*[a]
Abstract: Four novel 1,8-disubstituted
naphthalene derivatives 4–7 that con-
tain chalcogen atoms occupying the
peri positions have been prepared and
fully characterised by using X-ray crys-
tallography, multinuclear NMR spec-
troscopy, IR spectroscopy and MS. Mo-
lecular distortion due to noncovalent
substituent interactions was studied as
a function of the bulk of the interacting
chalcogen atoms and the size and
nature of the alkyl group attached to
them. X-ray data for 4–7 was compared
to the series of known 1,8-bis-
served for molecules containing bulkier
atoms at the peri positions. The de-
creased S···S distance from phenyl-1
and ethyl-4 analogues is ascribed to a
weaker chalcogen lone pair–lone pair
repulsion acting in the ethyl analogue
due to the presence of two equatorial
pared and fully characterised by using
X-ray crystallography and multinuclear
NMR spectroscopy, IR spectroscopy
and MS. Molecular structures were an-
alysed by using naphthalene ring tor-
sions, peri-atom displacement, splay
angle magnitude, S···S interactions, aro-
matic ring orientations and quasi-linear
O=S···S arrangements. The axial S-
SACHTUNGTRENNUG
A
U
ACHTUNGTRNE(NUNG naphthyl) rings in 8 and 9 are unfav-
E
ourable for S···S contacts due to stron-
ger chalcogen lone pair–lone pair re-
pulsion. Although quasi-linear O=S···S
alignments suggest attractive interac-
tion is conceivable, analysis of the
B3LYP wavefunctions affords no evi-
dence for direct bonding interactions
between the S atoms.
ent valence states of sulfur, were pre-
Keywords: ab initio calculations ·
chalcogens · density functional cal-
culations · naphthalene · peri-substi-
tution · X-ray diffraction
ACHTUNGTRENNUNG(phenylchalcogeno)naphthalenes 1–3,
which were themselves prepared from
novel synthetic routes. A general in-
crease in the E···E’ distance was ob-
Introduction
heavy polarisable elements in close proximity through a
rigid C2 backbone and, therefore, are ideal models for study-
ing such non-covalent interactions.
Atomic interactions are a fundamental aspect of chemistry,
biology and materials science.[1] Great advances have been
made in the area of strong covalent and ionic bonding, but
the major challenge for chemists of developing a full under-
standing of weak intra- and intermolecular forces still re-
mains. peri-Substituted naphthalenes are able to constrain
The peri-carbon atoms of “ideal” naphthalene are sepa-
rated by a distance of 2.44 ꢀ,[2] which is sufficient for ac-
commodating two hydrogen atoms, but it is reasonable to
expect that larger substituents at the peri positions will ex-
perience considerable steric hindrance.[3] Although this is
true, intramolecular interactions between peri substituents
can also be attractive due to the presence of weak or strong
bonding.[4] The ease of forming sterically crowded peri-sub-
stituted naphthalenes is influenced by the steric strain. This
is relieved either through bond formation or interaction be-
tween peri atoms, or through naphthalene distortion that ef-
fectively changes the geometry away from that of ideal
naphthalene. The most common forms of naphthalene dis-
tortion are in-plane and out-of-plane deviations of the exo-
cyclic bonds and buckling of the naphthalene ring system.[3]
The availability of X-ray structural data plays a crucial
role in assessing the repulsive steric effects between heavy
peri substituents and, therefore, quantifying the distortion in
[a] F. R. Knight, Dr. A. L. Fuller, Dr. M. Bꢁhl, Prof. A. M. Z. Slawin,
Prof. J. D. Woollins
School of Chemistry
University of St Andrews
St Andrews, Fife
KY16 9ST (UK)
Fax : (+44)1334-463384
E-mail: jdw3@st-and.ac.uk
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.200902523, and contains X-ray
crystallographic files for compounds 4–9, experimental procedures for
compounds 1–3 and 77Se chemical shift calculations for 2, 22+ and a
number of mono- and diprotonated variants of 2.
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non-ideal naphthalenes.[5] Molecular structures also help to
elucidate attractive effects between peri atoms and verify
the existence of weak intra- and intermolecular interactions.
To quantify the extent of naphthalene distortion taking
place in a given molecule, the naphthalene geometry is com-
pared with that of ideal, or un-substituted, naphthalene.[2]
In-plane distortion is calculated by observing the sum of
angles in the bay region (splay angles); in the ideal geome-
try these angles total 357.28 (Figure 1b).[2] If the sum of the
the naphthalene to distort away from the idealised geome-
try; however, as non-bonded distances decrease relative to
the sum of vdW radii, weak non-covalent interactions
become more covalent in nature, thus reducing the steric
hindrance between two heavy atoms.[14]
Figure 1. Measuring steric interactions and naphthalene distortions:
a) peri distance, b) sum of the bay region angles, c) distance of the peri
atoms from the mean naphthalene plane and d) torsion angles around
Herein we report the synthesis and structural analysis of
six novel peri-substituted chalcogen systems 4–9 and com-
pare the degree of molecular distortion and the occurrence
of non-covalent intramolecular chalcogen–chalcogen inter-
actions with the known series of compounds 1,8-bis(phenyl-
sulfanyl)naphthalene (1),[14,15] 1,8-bis(phenylselanyl)naphtha-
lene (2)[14,16] and 1,8-bis(phenyltelluro)naphthalene (3).[14,17]
Compounds 1–3 were prepared by using new synthetic
routes that were replicated for the synthesis of the novel S-
À
the C(5) C(10) bond.
splay angles is greater than this value (positive splay angle)
we can conclude the bonds have moved apart, which indi-
cates steric repulsion, but if the sum is lower (negative splay
angle), then the atoms have come closer as a result of fa-
vourable interactions.[2,5,6]
AHCTUNGERTG(NNUN ethyl) analogue of 1, 1,8-bis(ethylsulfanyl)naphthalene (4),
Likewise, out-of-plane distortion can be measured from
the distance that the peri substituents reside above and
below the naphthalene plane (Figure 1c); in ideal naphtha-
lene the peri hydrogens lie on the naphthyl plane.[2] Lastly,
torsion angles can indicate the level of planarity in the mole-
cule and give an insight into the degree of buckling taking
place in the naphthalene ring system (as depicted by the
C(1)-C(10)-C(5)-C(6) angle in Figure 1d). In ideal naphtha-
lene, the torsion angles are either 0 or 1808, depicting total
planarity.[2,5] The three types of distortion are cumulatively
expressed by the value of the peri distance, which is used as
the primary parameter when describing the distortion away
from ideal and also indicates the presence of peri-atom in-
teraction (Figure 1a).[5]
and an analogous series of related novel mixed 1,8-(phenyl-
chalcogeno)naphthalenes 5–7. Oxidation of 1 with different
molar equivalents of meta-chloroperoxybenzoic acid
(MCPBA) afforded two novel oxides 8 and 9. Molecular
structures of 1, 2 and 4–9 were determined by X-ray crystal-
lographic analysis, although 1[14,15] and 2[14,16] have been pre-
viously reported.
The structures of a series of Nap[G][ZR] (nap=naphtha-
lene-1,8-diyl; G=Cl, Br, F, H, SeMe) have been well docu-
mented by Nakanishi et al. into three geometrical types A
À
(in which the Z R bond lies perpendicular to the naphthyl
À
plane), B (in which the Z R bond lies with the naphthyl
plane) and C (intermediate between A and B).[1,11,13,18] The
structures for Nap[RZ]ACTHUNRGTNE[NUG R’Z] compounds can also be classi-
A number of groups have been investigating peri-substi-
tuted naphthalenes involving two heavy atoms at the 1,8 po-
sitions, in an effort to understand the factors that influence
the degree of distortion.[7] During our own studies, we have
investigated some sterically crowded 1,8-disubstituted naph-
thalenes.[5,8,9]
Positioning chalcogen atoms at the naphthalene 1,8 posi-
tions provides a good system with which to study the naph-
thalene distortion and the emergence of non-covalent peri-
atom interactions. An ideal naphthalene model that places
chalcogen atoms in the peri positions would result in very
short non-bonded distances, smaller than the sum of the van
der Waals (vdW) radii for the two atoms minus roughly
1 ꢀ.[1,7h,10–13] The resulting steric strain occurring in non-
bonded peri-substituted systems would be expected to cause
fied by a pairing of geometrical types denoted by AA-t,
AA-c, AB, BB or CC (-t denotes a trans conformation, -c
denotes cis).[1,12–14,17,19] The molecular structures of 1–9 were
analysed for naphthalene ring torsions, peri-atom displace-
ment, splay angle magnitude, E···E’ interactions, aromatic
À
ring orientations and quasi-linear X E···E’ arrangements to
establish geometric controlling factors. The structural con-
formations of 1–9 were characterised based on the classifica-
tion system reported by Nakanishi et al.[1,12–14]
Results and Discussion
Compounds 1–9 were synthesised and their crystal struc-
tures were determined. Additionally, except for the three
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1,8-Chalcogen Naphthalene Derivatives
FULL PAPER
previously reported compounds (1–3),[14–17] all the new com-
pounds were characterised by multinuclear NMR and IR
spectroscopies and mass spectrometry, and the homogeneity
of the new compounds was, where possible, confirmed by
microanalysis.
The series of 1,8-bis(phenylchalcogeno)naphthalene com-
pounds (1–3) was prepared through stepwise halogen–lithi-
um exchange reactions of analogous 1,8-dibromonaphtha-
lene (11)[20] and 1,8-diiodonaphthalene (12)[21] (Scheme 1).
Scheme 3. The preparation of
TMEDA (15). Conditions: PhEEPh, Et2O, À788C.
1 and 2 from 1,8-dilithionaphthalene·
and diphenyl ditelluride by using the same method was un-
successful.
Compounds 1–3 were characterised by using elemental
analysis, IR spectroscopy, 1H and 13C NMR spectroscopy
and mass spectrometry.[14–17] Compound 2 was analysed by
using 77Se NMR spectroscopy (d=428.6 ppm; lit. value: d=
435.4 ppm[14]) and 3 was analysed by using 125Te NMR spec-
troscopy (d=619.4 ppm; lit. value: d=617 ppm[17]).
Stepwise halogen–lithium exchange reactions of 11 and 12
were utilised for the preparation of the novel compound 1,8-
bis(ethylsulfanyl)naphthalene 4 in yields of 27 and 80%
based on 11 and 12, respectively (Scheme 4).
Scheme 1. The preparation of 1,8-bis(phenylchalocgeno)naphthalenes 1–
3. Conditions: i) nBuLi (2 equiv), Et2O, À788C, 1 h; ii) PhEEPh
(2 equiv), Et2O, À788C, 1 h.
For their synthesis, compounds 11 and 12 were independent-
ly treated with two equivalents of n-butyllithium in diethyl
ether to give the precursor, 1,8-dilithionaphthalene. Addi-
tion of diphenyl disulfide, diphenyl diselenide and diphenyl
ditelluride afforded the respective doubly substituted 1,8-
bis(chalcogenide) product (yield of 1: 22, 20%; yield of 2:
75, 82%; yield of 3: 37, 23%; first yield for each compound
based on 11 and second yield based on 12).
Due to the laborious and low-yielding route to both 1,8-
dibromo-[20] and 1,8-diiodonaphthalene,[21] a more efficient
synthesis of compounds 1–3 was undertaken by preparing
1,8-dilithionaphthalene directly from commercially available
1-bromonaphthalene (13) in the presence of tetramethyleth-
Scheme 4. The preparation of 1,8-bis(ethylsulfanyl)naphthalene (4). Con-
ditions: i) nBuLi (2 equiv), Et2O, À788C, 1 h; ii) EtSSEt (2 equiv), Et2O,
À788C, 1 h.
ACHTUNGTRENNUNG
As part of our ongoing investigation of molecular distor-
tion in peri-substituted naphthalenes and intramolecular in-
teractions, we have recently synthesised and investigated the
sive product following the reflux of 1-naphthyllithium with
BuLi·TMEDA (Scheme 2),[22] reacted with diphenyl disul-
fide and diphenyl diselenide to afford 1 (13% yield) and 2
(14% yield), respectively (Scheme 3). However, the prepa-
ration of tellurium analogue 3 from 1-bromonaphthalene
structures of the series of compounds Nap[X]ACHTNUTRGNE[NUG EPh] (X=Br,
I; E=S, Se, Te; Figure 2).[23] Upon treatment with one
Figure 2. The products of single substitution reactions of 1,8-dibromo-
and 1,8-diiodonaphthalene with diphenyl dichalcogenides.[23]
molar equivalent of n-butyllithium followed by one equiva-
lent of an appropriate diphenyl dichalcogenide, 11 and 12
undergo stepwise halogen–lithium exchange reactions to
form singly substituted 1-halo-8-(phenylchalcogeno)naph-
thalenes 16–21 (Figure 2).[23] Further reaction of 16–21 with
n-butyllithium and a suitable diphenyl dichalcogenide af-
forded three novel mixed chalcogen ligands (5–7).
Scheme 2. The preparation of 1,8-dilithionaphthalene·TMEDA (15).[22]
Conditions: i) nBuLi (1 equiv), Et2O, À308C; ii) TMEDA, hexane,
À308C; iii) nBuLi (1 equiv), À308C.
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J. D. Woollins et al.
1-Bromo-8-(phenylsulfanyl)naphthalene (16) and 1-iodo-
8-(phenylsulfanyl)naphthalene (17) were treated with n-bu-
tyllithium and diphenyl diselenide to afford the novel com-
pound 1-(phenylselanyl)-8-(phenylsulfanyl)naphthalene 5 in
75 and 63% yield based on 16 and 17, respectively
(Scheme 5). Analogous reactions starting from 1-bromo-8-
Scheme 7. The preparation of 1-(phenyltelluro)-8-(phenylselanyl)naph-
thalene (7). Conditions: i) nBuLi (1 equiv), Et2O, À788C, 1 h; ii) PhTe-
TePh (1 equiv), Et2O, À788C, 1 h.
Scheme 5. The preparation of 1-(phenylselanyl)-8-(phenylsulfanyl)naph-
thalene (5) from 1-halo-8-(phenylsulfanyl)naphthalenes 16, 17, 18 and 19.
Conditions: i) nBuLi (1 equiv), Et2O, À788C, 1 h; ii) PhEEPh (1 equiv),
Et2O, À788C, 1 h.
Scheme 8. The preparation of oxidised compounds 8 and 9. Conditions:
i) MCPBA (1 equiv (8) or 2–6 equiv (9)), Et2O.
MCPBA with 1 produced dioxide 9 with both sulfur atoms
mono-oxidised (Scheme 8). The treatment of 1 with further
equivalents (3–6) of MCPBA gave compound 9 exclusively,
and no higher oxidation to give the tri- or tetraoxide was
observed.
(phenylselanyl)naphthalene (18) and 1-iodo-8-(phenylsela-
nyl)naphthalene (19) afforded desired product 5 upon treat-
ment with diphenyl disulfide, but in lower yields of 34 and
15% based on 18 and 19, respectively (Scheme 5). The
77Se NMR spectrum (in CDCl3) shows a single peak at d=
455.3 ppm. Other details are given in the Experimental Sec-
tion.
Similar halogen–lithium exchange reactions of 16 and 17
afforded compound 6 in 51 and 88% yield, respectively
(Scheme 6). The 125Te NMR spectrum of 6 (in CDCl3) shows
X-ray investigations: Suitable single crystals of 1, 2 and 4–9
were obtained by diffusion of pentane into saturated solu-
tions of the individual compound in dichloromethane. The
molecular structures of 1–9 were analysed, although 1,[14,15]
2[14,16] and 3[14,17] have been previously reported. Compounds
1, 2, 4, 5, 8 and 9 crystallise with one molecule in the asym-
metric unit, and compounds 6 and 7 contain two nearly
identical molecules in the asymmetric unit (Figure 3 shows
the structures of 4–9). Selected interatomic distances, angles
and torsion angles are listed in Table 1. Further crystallo-
graphic information can be found in the Supporting Infor-
mation.
The steric strain introduced in 1–3 and 5–7 by the substi-
tution of heavy chalcogen atoms in the bay region is re-
leased by out-of-plane and in-plane distortions associated
with significant twisting of the naphthalene backbone (see
the central torsion angles of the naphthalene ring in
Table 1). The degree of geometrical distortion is related to
the size of the chalcogen atoms that occupy the peri posi-
tions in the naphthalene molecules. This is best observed
when comparing the magnitude of the peri distance parame-
Scheme 6. The preparation of 1-(phenyltelluro)-8-(phenylsulfanyl)naph-
thalene (6). Conditions: i) nBuLi (1 equiv), Et2O, À788C, 1 h; ii) PhTe-
TePh (1 equiv), Et2O, À788C, 1 h.
a single peak at d=715.2 ppm. The preparation of 6 starting
from 1-bromo-8-(phenyltelluro)naphthalene (20) and di-
phenyl disulfide was unsuccessful and may indicate that the
À
facile cleavage of the Te CNap bond is more susceptible to
attack by n-butyllithium rather than the bromine substitu-
ent.
ter for the six compounds. The EACTHNUGRTNEUNG(phenyl) groups lie in close
Compound 7 was prepared by treating bromo derivative
18 and iodo derivative 19 with n-butyllithium and diphenyl
ditelluride (81, 18% yield based on 18 and 19, respectively;
Scheme 7). The 77Se and 125Te NMR spectra of 7 (in CDCl3)
show single peaks at d=362.8 and 687.6 ppm, respectively,
with chemical shifts that are similar to those recorded for 5
proximity, with non-bonded interatomic peri distances
(E···E’) that display a general increase when larger atoms
occupy the close-contact 1,8-positions (see Table 1). The
E···E’ distances (3.00–3.29 ꢀ) are less than the respective
sum of the vdW radii for the two interacting atoms (3.60–
4.12 ꢀ);[10] in all cases this distance is between 79 and 83%
of the vdW sum (Table 1). These short non-bonded peri dis-
tances indicate the possible existence of weak intramolecu-
lar interactions.[24]
(77Se NMR: d=455.3 ppm) and
6
(
125Te NMR: d=
715.2 ppm).
Treatment of 1 with one equivalent of meta-chloroperben-
zoic acid (MCPBA) in diethyl ether afforded novel mono-
substituted oxide 8 (Scheme 8). Reacting two equivalents of
In each of the six compounds, the individual chalcogen
atoms are displaced to different sides of the naphthalene
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1,8-Chalcogen Naphthalene Derivatives
FULL PAPER
to minimise the steric repulsion
between the two bulky chalco-
gen atoms (“peri-space crowd-
ing”).[25]
Like analogues 1–3, com-
pounds 5–7 can be thought of
as structural “Siamese twins”
that are instead formed from
two, non-identical diphenyl di-
chalcogenide
parts
fused
through one benzene ring.[15]
The conformation and arrange-
ment of the E
ACHTUNGTREN(NUNG naphthyl) and
EACHTUNGTR(EUNNNG phenyl) rings relative to the
C(ar)-E(1)-C(ar) and C(ar)-
E(2)-C(ar) planes can be cate-
gorised from torsion angles q
and
g,
respectively
(see
Table 2). When q and g ap-
proach 908 the orientation is
denoted axial, and when the
angles indicate a quasi-planar
arrangement (close to 1808)
they are termed equatorial.[15]
Compounds 5–7 display
a
mixed axial–equatorial confor-
mation of the naphthyl and
phenyl rings around the chalco-
gen atom in each independent
half of the molecule. This orien-
tation, which matches that of
1[15] and 2[14] and is commonly
found in diaryl sulfides,[26] gives
these compounds an “aircraft-
like” shape (Figure 4).[15]
The S···Se, Te···S and Te···Se
atoms in naphthalene deriva-
tives 5–7, with separations
shorter than the sum of vdW
radii (3.70, 3.86 and 3.96 ꢀ),[10]
are fixed in unavoidably close
proximity. Repulsive E···E’ in-
teractions between the peri
Figure 3. The crystal structures of 1,8-bis(ethylsulfanyl)naphthalene (4), 1-(phenylselanyl)-8-(phenylsulfanyl)-
naphthalene (5), 1-(phenyltelluro)-8-(phenylsulfanyl)naphthalene (6; two independent molecules in the unit
cell), 1-(phenyltelluro)-8-(phenylselanyl)naphthalene (7), 1-(phenylsulfinyl)-8-(phenylsulfanyl)naphthalene (8)
and 1,8-bis(phenylsulfinyl)naphthalene (9).
least-squares plane. The displacement of the E atoms from
this plane ranges from 0.15 to 0.57 ꢀ, with an overall in-
crease in the out-of-plane distortion observed as the size of
the chalcogen atoms increases. The least amount of steric
strain is observed in 1, as indicated by the relatively small
atoms transpire and force the distortion of the naphthalene
À
geometry by stretching the C C bonds and C-C-C angles to-
gether with a buckling of the naphthalene skeleton. Bond
lengths around C(10), which is closer to the repulsive inter-
actions, are on average longer than those around C(5) (aver-
age lengths 1.44 and 1.42 ꢀ, respectively) and C(1)-C(10)-
C(9) bond angles splay to a mean 1268 away from the ideal
geometry observed for C(4)-C(5)-C(6) (average 1198).[2] The
aforementioned bond stretching and angle widening distor-
tions alone are insufficient to overcome the steric strain be-
tween the peri atoms. Supplementary widening of the E(1)-
C(1)-C(10) and E(2)-C(9)-C(10) angles and displacement of
the E atoms from the mean naphthyl plane takes place to
aid the alleviation of steric pressure.
displacement of the two small sulfur atoms (SrvdW
=
3.60 ꢀ)[10] from the naphthyl plane by À0.16 and 0.27 ꢀ.
The out-of-plane distortion is most pronounced and ob-
served to the greatest extent in 3, in which the displacement
of the two large tellurium atoms (SrvdW =4.12 ꢀ)[10] is À0.51
and 0.57 ꢀ. Considerable distortion of the bay area geome-
try within the naphthyl plane is observed in all six com-
pounds, with positive splay angles of 11.8 to 15.08 that
À
ensure that the E C bonds are tilted in opposite directions
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J. D. Woollins et al.
Table 1. Selected interatomic distances [ꢀ] and angles [8] for 1–9.[a]
3[14,17]
1
2
4
5
6
7
8
9
peri-region distances
E(1)···E’(9)
3.0036(13) 3.1332(9) 3.287(1) 2.9323(13) 3.063(2)
3.0684(13)
(3.0984(11))
0.79 (0.76)
3.1919(11)
(3.1580(12))
0.77 (0.80)
81 (80)
3.0460(11) 3.0757(13)
SrvdWÀE···E’[b]
0.6
0.67
0.83
0.67
0.64
0.55
85
0.52
85
[b]
SrvdW [%]
83
82
80
81
83
79 (80)
À
E(1) C(1)
1.794(3)
1.783(4)
1.922(7)
1.930(7)
2.14(1)
2.14(2)
1.776(4)
1.778(4)
1.907(9)
1.813(8)
2.141(5) (2.100(5))
1.770(5) (1.771(5))
2.137(11) (2.124(10)) 1.830(3)
1.920(12) (1.925(10)) 1.774(3)
1.814(3)
1.804(3)
À
E’(9) C(9)
naphthalene bond lengths
À
C(1) C(2)
1.379(5)
1.381(10) 1.34(1)
1.400(11) 1.38(1)
1.357(11) 1.34(1)
1.420(10) 1.46(1)
1.423(10) 1.42(1)
1.436(10) 1.39(1)
1.371(10) 1.35(1)
1.381(12) 1.38(1)
1.368(10) 1.37(1)
1.383(5)
1.402(5)
1.352(5)
1.415(5)
1.439(5)
1.423(5)
1.355(6)
1.402(6)
1.379(5)
1.439(5)
1.453(5)
–
1.367(12)
1.372(14)
1.375(15)
1.426(14)
1.435(12)
1.413(14)
1.363(15)
1.435(14)
1.381(13)
1.423(12)
1.447(12)
–
1.379(6) (1.386(8))
1.424(8) (1.404(8))
1.357(9) (1.367(6))
1.413(7) (1.423(8))
1.440(7) (1.433(8))
1.408(8) (1.416(6))
1.362(7) (1.356(9))
1.395(8) (1.399(9))
1.380(8) (1.381(6))
1.437(6) (1.433(7))
1.441(7) (1.436(6))
–
1.388(18) (1.415(13)) 1.376(4)
1.414(19) (1.426(16)) 1.413(5)
1.367(15) (1.335(18)) 1.359(4)
1.428(18) (1.393(14)) 1.416(5)
1.409(17) (1.449(16)) 1.436(4)
1.437(13) (1.412(18)) 1.421(4)
1.402(18) (1.362(15)) 1.366(5)
1.355(19) (1.392(17)) 1.401(5)
1.360(14) (1.378(18)) 1.387(4)
1.451(16) (1.428(14)) 1.424(4)
1.449(12) (1.470(16)) 1.439(4)
1.365(5)
1.408(5)
1.344(6)
1.427(5)
1.438(5)
1.407(6)
1.359(5)
1.397(5)
1.386(5)
1.432(4)
1.433(5)
1.497(3)
1.486(3)
À
C(2) C(3)
1.408(5)
1.348(6)
1.428(5)
1.442(5)
1.416(5)
1.362(5)
1.405(5)
1.374(5)
1.431(5)
1.446(5)
–
C(3)-C(4)
À
C(4) C(5)
À
C(5) C(10)
À
C(5) C(6)
À
C(6) C(7)
À
C(7) C(8)
À
C(8) C(9)
À
C(9) C(10)
1.436(9)
1.41(2)
À
C(10) C(1)
1.461(9)
1.45(1)
À
S(1) O(1)
–
–
–
–
–
–
1.500(2)
–
À
S(2) O(2)
–
–
–
–
peri-region bond angles
E(1)-C(1)-C(10)
C(1)-C(10)-C(9)
E(9)-C(9)-C(10)
S of bay angles
splay angle[c]
121.8(2)
126.8(3)
124.5(2)
373.1
123.5(5)
126.6(6)
123.8(5)
373.9
123(1)
128(1)
124(1)
375.0
15.0
122.6(2)
126.1(3)
122.1(2)
370.8
122.3(6)
127.8(7)
122.3(6)
372.4
122.9(3) (123.2(4))
126.1(4) (126.1(5))
122.8(4) (122.9(3))
371.8 (372.2)
125.2(9) (126.4(6))
125.5(10) (124.9(9))
123.6(7) (123.4(9))
374.3 (374.7)
126.8(2)
126.4(3)
122.1(2)
375.3
125.7(2)
128.0(3)
121.5(3)
375.2
13.1
13.9
10.8
12.4
11.8 (12.2)
14.3 (14.7)
15.3
15.2
C(4)-C(5)-C(6)
O(1)-S(1)-C(1)
O(1)-S(1)-C(11)
O(1)-S(1)···S(2)
O(2)-S(2)-C(9)
O(2)-S(2)-C(17)
O(2)-S(2)···S(1)
118.8(3)
117.3(6)
118.0(1) 118.8(3)
177.6(8)
117.4(10) (120.4(10)) 119.4(4) (119.0(5))
119.6(3)
105.0(1)
104.3(2)
174.3(1)
–
119.4(3)
105.3(2)
105.3(2)
171.9(1)
106.9(2)
106.8(2)
120.8(1)
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
out-of-plane displacement
E(1)
0.270(4)
0.468(9)
À0.51(1) 0.182(4)
0.432(11)
À0.565(7)
0.372(15) (À0.50(1))
0.010(4)
0.121(5)
(À0.406(7))
E(9)
O(1)
O(2)
À0.163(4) À0.327(9) 0.57(1)
À0.176(5) À0.320(11) 0.146(7) (0.449(7))
À0.43(2) (0.17(1))
0.210(4)
0.020(5)
–
À0.213(4)
0.129(6)
À0.1545(6)
–
–
–
–
–
–
–
–
–
–
–
–
–
–
central naphthalene ring torsion angles
C(6)-C(5)-C(10)-
C(1)
C(4)-C(5)-C(10)-
C(9)
178.6(3)
173.5(6)
174.2(1) À178.7(3) À175.2(8) À176.9(6) (176.7(6))
175.1(1) À178.9(3) À174.5(8) À174.6(6) (173.8(5))
À177.4(1)
(À174.8(1))
À175.0(1)
(À176.9(1))
À179.4(3) À179.5(3)
À177.7(3) 179.0(3)
177.2(3)
174.6(6)
[a] Values in parentheses are for independent molecules. [b] vdW radii used for calculations: rvdW(S)=1.80 ꢀ, rvdW(Se)=1.90 ꢀ, rvdW(Te)=2.06 ꢀ.[10]
[c] Splay angle: Sum of the three bay region anglesÀ360.
Table 2. Torsion angles [8] categorising the naphthalene and phenyl ring conformations in 5–7.[a]
5
6
7
Torsion angle Conformation
Torsion angle
Conformation
Torsion angle
Conformation
naphthalene ring conformations
C(10)-C(1)-E(1)-C(11) q1 =À156.4(7) Nap1: equatorial q1 =À160.5(11) (À168.1(11)) Nap1: equatorial q1 =À165.3(5) (160.8(5)) Nap1: equatorial
C(10)-C(9)-E(2)-C(17) q2 =111.3(7)
phenyl ring conformations
Nap2: axial
q2 =À83.1(11) (À82.3(12))
Nap2: axial
q2 =À84.0(5) (81.9(5))
Nap2: axial
C(1)-E(1)-C(11)-C(12) g1 =À98.0(8)
Ph1: axial
Ph2: equatorial
g1 =108.0(11) (À91.0(8))
g2 =À12.3(9) (À17.5(9))
Ph1: axial
Ph2: equatorial
g1 =À89.5(4) (108.1(6))
g2 =À12.5(5) (10.6(4))
Ph1: axial
Ph2: equatorial
C(9)-E(2)-C(17)-C(18) g2 =À9.3(9)
[a] Values in parentheses are for independent molecules. Definitions: Nap1: naphthalene ring E(1); Nap2: naphthalene ring E(2); Ph1: E(1) phenyl ring;
Ph2: E(2) phenyl ring; axial: perpendicular to C(ar)-E-C(ar) plane; equatorial: coplanar with C(ar)-E-C(ar) plane.
A similar displacement of the peri atoms to either side of
the naphthalene least-squares plane in 5 and 6 (5: 0.43 and
À0.32 ꢀ; 6: À0.57 (À0.41) and 0.15 ꢀ (0.45 ꢀ)) reveals that
steric strain in the two compounds is roughly equivalent.
7508
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Chem. Eur. J. 2010, 16, 7503 – 7516

1,8-Chalcogen Naphthalene Derivatives
FULL PAPER
((1.77Æ0.05), (1.93Æ0.05) and (2.12Æ0.05) ꢀ, respective-
ly)[27] in all three compounds. Although intermolecular short
contacts exist in all three derivatives in the molecular struc-
tures, there is no significant overlap of phenyl or naphtha-
lene rings and no p stacking.
Steric strain operating between the peri atoms in 1–3 and
5–7 is dominated by the repulsion of chalcogen p-type lone
pairs, which thus have a big influence on non-bonded E···E’
Figure 4. The crystal structures of 5–7 (from left to right) showing the
conformation of the EACHTUNGTRENNUNG(naphthyl) and EACHTUNGTNER(NUGN phenyl) rings.
distances. When the conformation of the EACTHNUGRTENUNG(naphthyl) group
is axial (torsion angles q1 and q2 approach 908; Table 2), the
axis of the p orbitals of the chalcogen atom lie in the plane
of the aromatic system and repulsion is relatively high.[15,19b]
Conversely, when torsion angles q1 and q2 approach 1808 (E-
Corresponding splay angles for 5 (12.48) and 6 (11.88
À
(12.28)) also implies that the E C bonds are tilted away
from each other to a similar extent to minimise the steric re-
pulsion operating between the chalcogen atoms. Non-
bonded E···E’ interatomic distances in 5 (3.063(2) ꢀ) and 6
(3.0684(13) ꢀ (3.0984(11) ꢀ)) are 0.64 and 0.79 ꢀ (0.76 ꢀ)
shorter than the sum of vdW radii for the two interacting
atoms (3.70, 3.86 ꢀ),[10] that is, only 83 and 79% (80%) of
the vdW sum for 5 and 6, respectively. The deviation of the
central naphthalene ring torsion angles from planarity is
similar in the two compounds but with a greater range in 6
(ꢀ5–68 in 5 and ꢀ2–68 in 6).
ACHTUNGTREN(NUGN naphthyl) conformation being equatorial), the p orbitals
are arranged parallel and vertical to the aromatic plane and
less lone pair–lone pair repulsion is observed.[15] The pres-
À
ence of a quasi-linear X E···E’ alignment of atoms allows
for the possible occurrence of an attractive E···E’ interac-
tion. Following the promotion of a chalcogen lone pair into
[28]
À
the antibonding s*
(S X) orbital,
a noncovalent three-
centre–four-electron (3c–4e) interaction emerges[29] and in-
fluences the conformation of the molecule.[14]
The structures for Nap[RZ]ACTHNUTRGENUGN[R’Z] compounds can be clas-
The increased congestion in the peri space of 7 causes a
sified by a pairing of geometrical types denoted by AA-t,
AA-c, AB, BB or CC.[1,12–14,17,19] Compounds 1[14,15] and
2[14,16] have been reported to adopt similar AB type confor-
À
larger positive splay of the E C bonds within the naphthyl
plane and an increased angle of 14.38 (14.78). The displace-
ment of the tellurium and selenium atoms from the naph-
thalene best plane (0.37 (À0.50), À0.43 ꢀ (0.17 ꢀ)) is com-
parable to the out-of-plane distortion that occurs in 5 and 6
(0.15–0.57 ꢀ). The naphthalene unit in 7 also shows a simi-
lar deviation from planarity to 5 and 6, with a maximum C-
C-C-C torsion angle of 5.28. The resulting geometry repels
the Te and Se atoms to a non-bonded interatomic distance
of 3.1919(11) ꢀ (3.1580(12) ꢀ), but this gap is still 19%
(20%) shorter than the sum of their collective vdW radii.
À
mations with one E CPh bond aligning close to the naphthyl
plane and one aligning roughly perpendicular to the
plane.[1,12–14] Bulkier tellurium analogue 3[14,17] adopts a CC
À
type structure with both E CPh bonds lying at roughly 1358
to the naphthyl plane (Figure 5).[1,12–14]
À
One attractive quasi-linear arrangement (C(11)
S(1)···S(2)) is observed in 1 with an angle of 168.48 and one
À
C(11) Se(1)···Se(2) alignment appears in 2 with an angle of
171.38. No similar linear arrangements are found in 3, which
À
À
À
À
À
The S C (1.72–1.82 ꢀ), Se C (1.88–1.98 ꢀ) and Te C
(2.07–2.17 ꢀ) bond lengths are within the usual ranges
has angles of 145.7 (C(11) Te(1)···Te(2)) and 154.28 (C(17)
Te(2)···Te(1)) (Figure 5).[17] The molecular structures of 5–7
Figure 5. The orientation of the EACHTUNGTRNEUNG
(phenyl) groups and structure types of 1–10 and the quasi-linear arrangements.[12–17,19b]
Chem. Eur. J. 2010, 16, 7503 – 7516
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www.chemeurj.org
7509

J. D. Woollins et al.
display an AB-type arrangement[1,12–14] equivalent to that re-
proaches 1808, whereas in 4 and 10[19b] both S
ACTHUNGTERNNU(G naphthyl) con-
formations are equatorial, the p orbitals are arranged paral-
lel to the aromatic plane and less lone pair–lone pair repul-
sion is observed (see Table 3).[15]
ported for 1 and 2.[14–16] In all cases one quasi-linear arrange-
À
ment of the type C E···E’ is observed with angles in the
range of 169–1728 (Figure 5).
The degree of steric strain operating between the peri
Compounds 4 and 10 both adopt the CC-t type arrange-
atoms in bis(S
N
ment[1,12–14] (Figure 5) in which the S C bonds lie on oppo-
À
the S
C
site sides of the naphthyl plane, intermediate between the
interaction displayed by 1,8-bis(methylsulfanyl)naphthalene
10 previously reported by Glass et al.[19b] The nature of the
alkyl substituent attached to the peri-sulfur atoms plays a
crucial role in determining the geometry of the three struc-
tures. The peri atoms are displaced by equal distances and
in opposite directions from the naphthalene least-squares
plane in both 4 (Æ0.18 ꢀ) and 10 (Æ0.30 ꢀ)[19b] but by un-
equal distances in 1 (0.27 and À0.16 ꢀ).[14,15] Positive splay
angles are comparable for 4 (10.88) and 10 (9.98),[19b] but
type
A (perpendicular) and type B (planar) arrange-
ments.[1,11,13,18] Two favourable quasi-linear C S···S moieties
À
À
À
are present in both 4 (C(11) S(1)···S(2) 157.328, C(13)
S(2)···S(1) 159.608) and 10 (C(11) S(1)···S(2) 155.48 (151.98),
C(12) S(2)···S(1) 168.38 (162.68)), which suggests an attrac-
tive S···S noncovalent interaction and could explain the rela-
À
À
tively short distances observed compared with bisACHTUNGTRENNUNG(sulfide)
1.[19b]
Oxides 8 and 9 adopt similar geometrical conformations
and display a similar degree of steric strain between the
sulfur peri atoms, but are notably different compared to the
À
there is a notable increase in the splay of the S C bonds in
1 (13.18)[14,15] to alleviate peri-space crowding.[25] The nonco-
valent S···S peri distances for
1
(3.0036(13) ꢀ),
4
non-oxidised bisACTHNGUTERNNUG
(sulfide) 1.[14,15] The presence of oxygen
(2.9323(13) ꢀ) and 10 (2.918(2) ꢀ (2.934(2) ꢀ)) are shorter
than double the vdW radius of sulfur by 0.67, 0.60 and
0.68 ꢀ (0.67 ꢀ), respectively. No major distortion of the
naphthalene scaffold is observed in 4, which has only a
minor deviation from planarity; the maximum C-C-C-C tor-
sion angle is 1.38 for C(6)-C(5)-C(10)-C(1). The deviation of
the central naphthalene ring torsion angles from planarity is
more pronounced in 1 (ꢀ1–38) and 10 (ꢀ48). Short inter-
molecular interactions are observed between two molecules
atoms bonded to the peri-sulfur substituents plays a crucial
role in determining the geometry of the oxides. Both com-
pounds are relatively planar with no major distortion of the
naphthalene scaffold observed. Only minor deviations from
planarity exist for 8 and 9, with maximum C-C-C-C torsion
angles of 2.3 and 1.08, respectively. The displacement of the
sulfur atoms from the naphthalene least-squares plane in 8
is insignificant, with S(1) essentially lying on the plane (0.01,
À0.16 ꢀ). The peri atoms in 9 (0.12, À0.21 ꢀ) are displaced
from the naphthalene plane in opposite directions and by
similar distances to 1 (0.27, À0.16 ꢀ).[14,15] Large and posi-
tive splay angles of 15.3 (8) and 15.28 (9), however, illustrate
that a big in-plane distortion is operating to alleviate peri-
space crowding.[25] The noncovalent S···S peri lengths for 8
(3.0460(11) ꢀ) and 9 (3.0757(13) ꢀ) are longer than in 1
(3.0036(13) ꢀ), but still 15% shorter than double the vdW
radius of sulfur in both cases.[10]
of 4 within the crystal structure: H
and H(12a)···H(13a) (2.32(1) ꢀ).
ACHUTNGTRENNUG(11b)···HACHUTNGTREN(NUGN 14a) (2.37(1) ꢀ)
N
ACHTUNGTRENNUNG
À
In compound 4, all the S C (1.78–1.82 ꢀ) bond lengths
are within the usual range ((1.77Æ0.05) ꢀ).[27] The repulsion
acting between the peri atoms is observed in the naphtha-
lene skeleton, with bond lengths around C(10) found to be
stretched and longer than those around C(5) (average: 1.45
and 1.42 ꢀ, respectively) and the C(1)-C(10)-C(9) angle,
which is most affected by the repulsion, splays to 1268 away
from the ideal geometry observed for C(4)-C(5)-C(6)
(1198).[2]
In the crystal structure of 8, there is an approximate align-
ment of the naphthalene rings along the c axis, with the clos-
est intermolecular short contact between C(3) and C(9)
(3.56(1) ꢀ). No similar alignment is observed in the struc-
ture of 9, but a short intermolecular distance exists between
The disparity between the larger non-bonded S···S length
observed in compound 1 (3.00 ꢀ),[14,15] compared with the
À
distances found in the ethyl- and methyl-analogues
4
S(1) and C(3) (3.43(1) ꢀ). All the S C (1.77–1.83 ꢀ) and S=
(2.93 ꢀ) and 10 (2.93 ꢀ),[19b] may reflect a stronger lone
pair–lone pair repulsion acting in the phenyl analogue. This
can be rationalised by comparing the torsion angles q1 and
O (1.49–1.50 ꢀ) bond lengths are within the usual ranges
((1.79Æ0.05) and (1.50Æ0.05) ꢀ, respectively).[27] Bond
lengths around C(10) are stretched longer, but to a lesser
extent than normal, than those around C(5) (average: 1.43
and 1.42 ꢀ, respectively) and angle C(1)-C(10)-C(9), which
q2 (Table 3) associated with SACHTUNGRTEN(NUNG naphthyl) conformations. In
bis
ACHTUNGTRENNUNG
Table 3. Torsion angles [8] categorising the naphthalene ring conformations in 1, 4 and 10.[a]
1
4
10[19b]
Torsion angle
naphthalene ring conformations
C(10)-C(1)-S(1)-C(11)
C(10)-C(9)-S(2)-C(17/3/2)
Conformation
Torsion angle
Conformation
Torsion angle
Conformation
q1 =159.8(2)
q2 =95.0(3)
Nap1: equatorial
Nap2: axial
q1 =À149.7(3)
q2 =À153.1(3)
Nap1: equatorial
Nap2: equatorial
q1 =À143.2 (À142.0)
q2 =À152.3 (À153.0)
Nap1: equatorial
Nap2: equatorial
ACHTUNGTRENNUNG
[a] Values in parentheses are for independent molecules. Definitions: Nap1: naphthalene ring E(1); Nap2: naphthalene ring E(2); axial: perpendicular to
C-E-C plane; equatorial: coplanar with C-E-C plane.
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Chem. Eur. J. 2010, 16, 7503 – 7516

1,8-Chalcogen Naphthalene Derivatives
FULL PAPER
is most affected by the repulsion, splays to a mean 1278
away from the ideal geometry observed for C(4)-C(5)-C(6)
(1208).[2]
The larger noncovalent S···S distances observed in oxides
8 and 9 (3.05, 3.08 ꢀ) compared with the equivalent distance
found in 1 (3.00 ꢀ) can be rationalised by comparing the S-
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
(torsion angles q1 and q2 approach 908, Table 4), the axis of
the p orbitals of the chalcogen atom lie in the plane of the
aromatic system and repulsion is relatively high.[15] Similarly,
in oxide 9 one is axial and one is a twist conformation. Con-
Figure 7. The crystal structures of 8 (left) and 9 (right) showing the pla-
narity of the naphthalene backbones and the overlap of the phenyl rings.
versely, in bisACHTUNGTRENNUNG
(sulfide) 1,[14,15] one of the torsion angles ap-
proaches 1808, the p orbitals arrange parallel to the aromatic
plane and less lone pair–lone pair repulsion is observed.[15]
Compounds 8 and 9 adopt different structural arrange-
ments compared with the AB-type arrangement[1,12–14] of
range for typical centroid–centroid p stacking (3.3–3.8 ꢀ),[30]
so possible p–p stacking could be envisaged (Figure 3).[30]
The AC-type arrangement[1,12–14] in 9 inhibits phenyl ring
non-oxidised 1 (Figure 5).[1,12–14] In compound 8, both S CPh
overlap, with the S CPh moiety of the C-type arrangement
À
À
bonds lie roughly perpendicular to and on the same side of
the naphthyl plane (AA-c-type),[1,12–14] with the quasi-linear
arrangement O(1)=S(1)···S(2) lying along the naphthyl plane
(174.38; Figures 6 and 7). Compound 9 adopts a similar
structure, but with the added bulk of the second oxygen
being inclined at a greater angle from the naphthalene plane
compared with the moiety that adopts the A-type arrange-
ment[1,11,13,18] (phenyl ring on S(1)). The phenyl ring bonded
to S(2) is also twisted upwards and impedes phenyl ring in-
teraction, which results in no p–p stacking taking place
(Figure 7).
À
atom, one of the S CPh bonds is distorted to ꢀ1358 and thus
classified as an AC-c type arrangement.[1,12–14] The same
linear arrangement of the type O(1)=S(1)···S(2) (171.98) is
observed and the second oxygen atom takes up position on
the opposite side of the naphthalene plane to give an
S(1)···S(2)=O(2) angle of 120.88.
To try and assess the possibility of direct S···S bonding in-
teractions that would indicate an onset of 3c–4e bonding,
density functional theory computations were performed for
derivatives 8 and 9 at the B3LYP/6-31+G* level. The
Wiberg bond index (WBI),[32] which measures the covalent
bond order, was calculated to be only 0.03 in both com-
pounds, which indicates a very minor interaction taking
place between these non-bonded atoms. For comparison, the
À
The AA-c-type arrangement[1,12–14] in compound 8 allows
for the close configuration and overlap of the two phenyl
rings.[30] The alignment of the rings is a face-to-face offset ar-
rangement with slipped packing, known as parallel displace-
ment (Figures 3 and 7).[30] The distance between the two in-
teracting centroids (3.821(1) ꢀ) is at the top end of the
fully covalent S S single bond in naphtho
thiole) has a WBI of 0.99 at the same level.
ACHTUNGTREN(NUGN 1,8-cd)(1,2-di-
More pronounced interactions could be expected as the
neighbouring chalcogens become larger. This expectation is
borne out by computations for 2, which afford a WBI of
0.08 between the two Se atoms. Even stronger interactions
can occur when one of the Se atoms carries an acceptor.
When the “equatorial” Ph group on Se(1) in 2 is replaced
À
with Br (for numbering see Figure 5), the Se Se lengths as
short as 2.516 ꢀ have been observed.[32] A B3LYP computa-
tion for the latter molecule from the X-ray structure affords
a WBI of 0.55, which suggestes a large extent of 3c–4e bond-
ing in this case. Judging from the refined chalcogen–chalco-
gen distances, none of the species in the present study
comes close to such a bonding situation.
Figure 6. The crystal structures of 8 (left) and 9 (right) showing the orien-
tation of the phenyl substituents.
Table 4. Torsion angles [8] categorising the naphthalene ring conformations in 8, 9 and 1.
8
9
1
Torsion angle
Conformation
Torsion angle
Conformation
Torsion angle
Conformation
naphthalene ring conformations
C(10)-C(1)-S(1)-C(11)
C(10)-C(9)-S(2)-CACHTUNGTRENNUNG(17/3/2)
q1 =À74.3(2)
q2 =118.5(3)
Nap1: axial
Nap2: axial
q1 =À70.5(3)
q2 =137.5(3)
Nap1: axial
Nap2: twist
q1 =159.8(2)
q2 =95.0(3)
Nap1: equatorial
Nap2: axial
[a] Definitions: Nap1: naphthalene ring E(1); Nap2: naphthalene ring E(2); axial: perpendicular to C-E-C plane; equatorial: coplanar with C-E-C plane;
twist: intermediate between axial and equatorial.
Chem. Eur. J. 2010, 16, 7503 – 7516
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7511

J. D. Woollins et al.
Compound 3 was first report-
ed by Furukawa et al.[17] Elec-
trochemical oxidation of 3 by
cyclic voltammetry revealed
one reversible oxidation peak
at a very low oxidation poten-
tial of +0.16 V.[17] Furukawa
et al. attributed this to the de-
stabilisation of 3 by peri lone
pair–lone pair repulsion and the
stabilisation of the oxidised spe-
Scheme 10. Computed enthalpies and mean 77Se chemical shifts (d [ppm], in italics) of 2 and selected protona-
tion and oxidation products thereof (B3LYP level).
cies by neighbouring-tellurium participation.[17] The
125Te NMR spectrum of 3 in CDCl3 has a peak at d=
617 ppm, whereas a solution of 3 in D2SO4 gave a downfield
shift to d=964 ppm, which suggests that it is a dication.[17]
Herein we report our 77Se and 125Te NMR spectroscopy
studies of 1,8-bis(phenylselanyl)naphthalene 2 and the three
mixed chalcogen compounds 5–7. Spectra for all four com-
pounds were run in both CDCl3 and D2SO4 to ascertain if
these compounds could also afford similar cationic species
(Scheme 9). The results of the 77Se and 125Te NMR studies
are shown in Table 5. For each NMR experiment there is a
onance with respect to that of 2 is obtained (Dd=533 ppm).
Quantitatively, this gas-phase result overestimates the trend
observed on going from the less polar solvent CDCl3 to the
highly polar sulfuric acid (Ddꢀ400 ppm, Table 5). The qual-
itative agreement between theory and experiment, however,
can be taken as strong support for formation of 22+ in
D2SO4.
Conclusion
The present work is a contribution to the investigations of
molecular distortion occurring in peri-substituted naphtha-
lene compounds and the significance of intramolecular inter-
actions occurring between heavy atoms when positioned at
the close 1,8-positions. Repulsive steric strain caused by in-
serting increasingly larger atoms at the 1,8-positions in six
chalcogen analogues (1–3 and 5–7) is shown to be relieved
to a greater extent as the overall combined size of the peri
atoms increases. The primary parameter used to quantify
the amount of strain relief in non-ideal naphthalenes is the
peri distance, which encapsulates all molecular deviations in
one parameter. The largest peri distance for the six com-
pounds was found in 3 (SrvdW 4.12 ꢀ), which is substituted
by two large tellurium atoms,[10] whereas the shortest peri
gap was observed in 1 (SrvdW 3.60 ꢀ), which contains the
two smallest (sulfur) substituents.[10] Although the non-
bonded distance is shorter than the sum of vdW radii for
the two peri atoms by 21–17% in all six compounds, no evi-
dence of bond formation was observed.
Scheme 9. The oxidation reaction of chalcogen compounds 2, 5–7 with
D2SO4.
[17]
Table 5. 77Se and 125Te NMR spectroscopy data (d [ppm]) run in CDCl3
and D2SO4 for 2 and 5–7.
2
5
6
7
peri atoms
Se, Se
Se, S
Te, S
Te, Se
77Se NMR (CDCl3)
77Se NMR (D2SO4)
125Te NMR (CDCl3)
125Te NMR (D2SO4)
428.6
828.0
–
455.3
927.3
–
–
–
362.8
554.7
687.6
715.2
1018.3
–
–
1279.6
Upon oxidation, the structure of bisACTHNUTRGNEUNG(sulfide) 1 is dramati-
significant downfield shift in the signal for spectra run in
D2SO4 compared with the signal for spectra run in CDCl3.
These results suggest the formation of a dicationic species in
each case (see Scheme 9).[17] To rule out protonated species
as a source for the observed NMR signals, we have calculat-
ed the 77Se chemical shifts for 2, 22+ and a number of mono-
cally changed and adopts either an AA-type arrange-
ment[1,12–14] (8) or an AC-type arrangement[1,12–14] (9). The
overriding factor in these two structures is a linear arrange-
ment of the type O(1)=S(1)···S(2), which in both cases
forces the two phenyl rings to align on the same side of the
naphthalene plane. In compound 8 this overlap is close
enough for possible p–p stacking to occur.[30] Ab initio MO
calculations performed on both derivatives by using the
B3LYP/6-31+G* level revealed WBI[31] values of 0.03,
which indicates that only a very minor interaction exists be-
tween the non-bonded sulfur atoms.
and diprotonated variants of
2 (see Scheme 10 and
Table S15 in the Supporting Information). Protonation is
predicted to result in a shielding of the Se nuclei by up to
Dd=À179 ppm for the (symmetrically bridged) monoproto-
nated form. Interestingly, a substantial driving force is com-
puted for H elimination from the diprotonated species,
DH=À37 kJmolÀ1, a process that will be further favoured
by entropy. For the resulting oxidised dication (rightmost
structure in Scheme 10), a notable deshielding of the Se res-
The oxidation of chalcogenides 2 and 5–7 was observed
by 77Se and 125Te NMR spectroscopy. A significant downfield
shift in the signal for spectra of the three derivatives run in
D2SO4 compared with the signal for spectra run in CDCl3
7512
www.chemeurj.org
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 7503 – 7516

1,8-Chalcogen Naphthalene Derivatives
FULL PAPER
rated solution of the crude compound in dichloromethane gave colourless
crystals (0.3 g, 80%).
reveals the formation of a peri bond and the presence of a
dication species.[17]
1-(Phenylselanyl)-8-(phenylsulfanyl)naphthalene (NapACTHNUTRGNENG(U SePh)ACHTUNGTRENN(UGN SPh); 5)
Synthesis of 5 from 18: A solution of n-butyllithium (2.5m, 1.1 mmol) in
hexane (0.5 mL) was added dropwise to a solution of 1-bromo-8-(phenyl-
selanyl)naphthalene (0.40 g, 1.1 mmol) in diethyl ether (20 mL) at
À788C. The mixture was stirred at this temperature for 1 h, after which a
solution of diphenyl disulfide (0.24 g, 1.1 mmol) in diethyl ether (20 mL)
was added dropwise to the mixture. The resulting mixture was stirred at
À788C for a further 1 h. The reaction mixture was washed with 0.1m
sodium hydroxide (2ꢃ45 mL). The organic layer was dried with magnesi-
um sulfate, concentrated under reduced pressure and the residual oil was
purified by column chromatography on silica gel (hexane). Recrystallisa-
tion by diffusion of pentane into a saturated solution of the compound in
dichloromethane gave the title compound as colourless crystals (0.2 g,
34%). 1H NMR (270 MHz, CDCl3, 258C, TMS): d=7.90–7.82 (m, 2H;
Experimental Section
All experiments were carried out under an oxygen- and moisture-free ni-
trogen atmosphere by using standard Schlenk techniques and glassware.
Reagents were obtained from commercial sources and used as received.
Dry solvents were collected from an MBraun solvent system. 1,8-Dibro-
monaphthalene (11)[20] and 1,8-diiodonaphthalene (12)[21] were prepared
by standard diazotisation reactions of 1,8-diaminonaphthalene. 1-Halo-8-
(phenylchalcogeno)naphthalenes 16–19[23] were prepared from 11 and 12.
Elemental analyses were performed by the University of St Andrews
School of Chemistry Microanalysis Service. IR spectra were recorded as
nap 5,7-H), 7.65 (dd, 3J
(H,H)=7.7 Hz, 4J
ACHUTGTNRENNUG CAHTUNGTRENNUNG
7.62–7.54 (m, 2H; SePh 2,6-H), 7.42 (t, 3J
AHCTUNGTRENNUNG
KBr discs in the range of 4000–300 cmÀ1 by using
a Perkin–Elmer
System 2000 Fourier transform spectrometer. 1H and 13C NMR spectra
were recorded by using a Jeol GSX 270 MHz spectrometer with d(H)
and d(C) referenced to external tetramethylsilane. 77Se and 125Te NMR
spectra were recorded by using a Jeol GSX 270 MHz spectrometer with
d(Se) and d(Te) referenced to external dimethylselenide and diphenyl di-
telluride, respectively. Assignments of 13C and 1H NMR spectra were
made with the help of H–H COSY and HSQC experiments. All measure-
ments were performed at 258C. All values reported for NMR spectrosco-
py are in parts per million (ppm). Coupling constants (J) are given in
Hertz (Hz). Mass spectrometry was performed by the University of St
Andrews Mass Spectrometry Service. Electron impact mass spectrometry
(EIMS) and chemical ionisation mass spectrometry (CIMS) was carried
out by using a Micromass GCT orthogonal acceleration time-of-flight
mass spectrometer. Electrospray mass spectrometry (ESMS) was carried
out by using a Micromass LCT orthogonal accelerator time-of-flight mass
spectrometer.
7.38–7.28 (m, 3H; SePh 3–5-H), 7.24–7.05 ppm (m, 7H; nap 2,3-H, SPh
2–6-H); 13C NMR (67.9 MHz, CDCl3, 258C, TMS): d=138.2 (s), 136.6
(s), 131.2 (s), 130.8 (s), 129.7 (s), 129.0 (s), 128.5 (s), 127.9 (s), 127.4 (s),
126.3 (s), 125.9 (s), 125.8 ppm (s); 77Se NMR (51.5 MHz, CDCl3, 258C,
PhSeSePh): d=455.3 ppm; 77Se NMR (51.5 MHz, D2SO4, 258C, PhSe-
SePh): d=927.3 ppm; IR (KBr disk): n˜max =3249 s, 3053 vs, 2957 w, 2862
w, 2638 w, 2583 w, 2386 w, 2336 w, 2168 w, 1944 s, 1876 w, 1818 w, 1773 w,
1720 w, 1644 w, 1574 vs, 1544 vs, 1474 vs, 1434 vs, 1381 w, 1353 s, 1323 s,
1261 s, 1194 s, 1152 w, 1076 s, 1618 vs, 998 w, 911 w, 861 w, 811 vs, 755 vs,
735 vs, 688 vs, 620 w, 573 w, 542 w, 472 cmÀ1 s; MS (CI+): m/z (%):
392.01 (33) [M]+, 314.97 (35) [MÀPh]+, 236.07 (100) [MÀPh2]+; elemen-
tal analysis calcd (%) for C22H16SSe: C 67.3, H 4.1; found: C, 66.7, H 4.2.
Synthesis of 5 from 16: A solution of n-butyllithium (2.5m, 0.72 mmol) in
hexane (0.3 mL) was added dropwise to a solution of 1-bromo-8-(phenyl-
sulfanyl)naphthalene (0.23 g, 0.72 mmol) in diethyl ether (20 mL) at
À788C. The mixture was stirred at this temperature for 1 h, after which a
solution of diphenyl diselenide (0.23 g, 0.72 mmol) in diethyl ether
(20 mL) was added dropwise to the mixture. The resulting mixture was
stirred at À788C for a further 1 h. The reaction mixture was washed with
0.1m sodium hydroxide (2ꢃ45 mL). The organic layer was dried with
magnesium sulfate, concentrated under reduced pressure and the residual
oil was purified by column chromatography on silica gel (hexane). Re-
crystallisation by diffusion of pentane into a saturated solution of the
compound in dichloromethane gave the title compound as colourless
crystals (0.2 g, 75%).
1,8-Bis(ethylsulfanyl)naphthalene (NapACTHNUGTRENUNG(SEt)2; 4)
Synthesis of 4 from 11: A solution of n-butyllithium (2.5m, 2.4 mmol) in
hexane (1.0 mL) was added dropwise to a solution of 1,8-dibromonaph-
thalene (0.34 g, 1.2 mmol) in diethyl ether (15 mL) at À788C. The mix-
ture was stirred at this temperature for 1 h after which a solution of di-
ethyl disulfide (0.29 g, 2.4 mmol, 0.3 mL) in diethyl ether (15 mL) was
added dropwise to the mixture. The resulting mixture was stirred at
À788C for a further 1 h. The reaction mixture was washed with 0.1m
sodium hydroxide (2ꢃ45 mL). The organic layer was dried with magnesi-
um sulfate, concentrated under reduced pressure and the residual oil was
purified by column chromatography on silica gel (hexane). Recrystallisa-
tion by diffusion of pentane into a saturated solution of the compound in
dichloromethane gave colourless crystals (0.08 g, 27%). 1H NMR
Synthesis of 5 from 19: A solution of n-butyllithium (2.5m, 0.3 mmol) in
hexane (0.1 mL) was added dropwise to a solution of 1-iodo-8-(phenylsel-
anyl)naphthalene (0.12 g, 0.3 mmol) in diethyl ether (15 mL) at À788C.
The mixture was stirred at this temperature for 1 h, after which a solution
of diphenyl disulfide (0.07 g, 0.3 mmol) in diethyl ether (15 mL) was
added dropwise to the mixture. The resulting mixture was stirred at
À788C for a further 1 h. The reaction mixture was washed with 0.1m
sodium hydroxide (2ꢃ45 mL). The organic layer was dried with magnesi-
um sulfate, concentrated under reduced pressure and the residual oil was
purified by column chromatography on silica gel (hexane). Recrystallisa-
tion by diffusion of pentane into a saturated solution of the compound in
dichloromethane gave the title compound as colourless crystals (0.02 g,
15%).
3
4
(270 MHz, CDCl3, 258C, TMS): d=7.65 (dd, J
N
N
3
4
1.2 Hz, 2H; 4,5-H), 7.55 (dd, J
(H,H)=7.5 Hz, J
7.39–7.30 (m, 2H; 3,6-H), 2.96 (q, 3J
ACHTUNGTRENNUNG
(t, 3J
ACHTUNGTRENNUNG
TMS): d=130.1 (s), 127.9 (s), 125.4 (s), 31.6 (s; CH2), 13.4 ppm (s; CH3);
IR (KBr disk): n˜max =3047 w, 2965 s, 2924 s, 2851 s, 1932 w, 1868 w, 1784
w, 1720 w, 1597 w, 1546 s, 1490 w, 1446 s, 1420 s, 1370 w, 1313 s, 1259 vs,
1193 s, 1093 s, 1046 s, 1022 s, 985 w, 900 w, 874 s, 811 vs, 759 vs, 713 w,
579 cmÀ1 w; MS (EI+): m/z (%): 248 (2) [M+], 219 (4) [MÀEt]+, 189.99
(100) [MÀEt2]+; elemental analysis calcd (%) for C14H16S2: C 67.7, H
6.5; found: C 66.8, H 6.5.
Synthesis of 5 from 17: A solution of n-butyllithium (2.5m, 0.47 mmol) in
hexane (0.2 mL) was added dropwise to a solution of 1-iodo-8-(phenyl-
sulfanyl)naphthalene (0.17 g, 0.47 mmol) in diethyl ether (20 mL) at
À788C. The mixture was stirred at this temperature for 1 h, after which a
solution of diphenyl diselenide (0.15 g, 0.47 mmol) in diethyl ether
(20 mL) was added dropwise to the mixture. The resulting mixture was
stirred at À788C for a further 1 h. The reaction mixture was washed with
0.1m sodium hydroxide (2ꢃ45 mL). The organic layer was dried with
magnesium sulfate, concentrated under reduced pressure and the residual
oil was purified by column chromatography on silica gel (hexane). Re-
crystallisation by diffusion of pentane into a saturated solution of the
Synthesis of 4 from 12: A solution of n-butyllithium (2.5m, 2.9 mmol) in
hexane (1.2 mL) was added dropwise to a solution of 1,8-diiodonaphtha-
lene (0.54 g, 1.4 mmol) in diethyl ether (10 mL) at À788C. The mixture
was stirred at this temperature for 1 h, after which a solution of diethyl
disulfide (0.4 mL, 0.35 g, 2.9 mmol) was added dropwise to the mixture.
The resulting mixture was stirred at À788C for a further 1 h. The reaction
mixture was washed with 0.1m sodium hydroxide (2ꢃ45). The organic
layer was dried with magnesium sulfate, concentrated under reduced
pressure and the residual oil was purified by column chromatography on
silica gel (hexane). Recrystallisation by diffusion of pentane into a satu-
Chem. Eur. J. 2010, 16, 7503 – 7516
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7513

J. D. Woollins et al.
compound in dichloromethane gave the title compound as colourless
crystals (0.1 g, 63%).
1535 w, 1474 s, 1431 s, 1328 w, 1261 w, 1189 w, 1138 w, 1062 s, 1019 s, 995
s, 953 w, 897 w, 839 w, 809 vs, 758 vs, 733 vs, 690 s, 665 w, 612 w, 456 cmÀ1 s;
MS (ES+): m/z (%): 410.99 (100) [MÀPh]+; elemental analysis calcd (%)
for C22H16SeTe: C 53.9, H 3.3; found: C 54.6, H 3.5.
1-(Phenyltelluro)-8-(phenylsulfanyl)naphthalene (NapACTHNUTRGNENG(U TePh)ACHTUNGTRENN(UGN SPh); 6)
Synthesis of 6 from 16: A solution of n-butyllithium (2.5m, 1.0 mmol) in
hexane (0.4 mL) was added dropwise to a solution of 1-bromo-8-(phenyl-
sulfanyl)naphthalene (0.32 g, 1.0 mmol) in diethyl ether (20 mL) at
À788C. The mixture was stirred at this temperature for 1 h, after which a
solution of diphenyl ditelluride (0.41 g, 1.0 mmol) in diethyl ether
(20 mL) was added dropwise to the mixture. The resulting mixture was
stirred at À788C for a further 1 h. The reaction mixture was washed with
0.1m sodium hydroxide (2ꢃ45 mL). The organic layer was dried with
magnesium sulfate, concentrated under reduced pressure and the residual
oil was purified by column chromatography on silica gel (hexane). Re-
crystallisation by diffusion of pentane into a saturated solution of the
compound in dichloromethane gave the title compound as yellow crystals
(0.2 g, 51%). 1H NMR (270 MHz, CDCl3, 258C, TMS): d=7.96–7.85 (m,
Synthesis of 7 from 19: A solution of n-butyllithium (2.5m, 0.40 mmol) in
hexane (0.2 mL) was added dropwise to a solution of 1-iodo-8-(phenylse-
lanyl)naphthalene (0.16 g, 0.40 mmol) in diethyl ether (20 mL) at À788C.
The mixture was stirred at this temperature for 1 h, after which a solution
of diphenyl ditelluride (0.16 g, 0.40 mmol) in diethyl ether (20 mL) was
added dropwise to the mixture. The resulting mixture was stirred at
À788C for a further 1 h. The reaction mixture was washed with 0.1m
sodium hydroxide (2ꢃ45 mL). The organic layer was dried with magnesi-
um sulfate, concentrated under reduced pressure and the residual oil was
purified by column chromatography on silica gel (hexane). Recrystallisa-
tion by diffusion of pentane into a saturated solution of the compound in
dichloromethane gave the title compound as yellow crystals (0.03 g,
18%).
4H; nap 5,7-H, TePh 2,6-H), 7.67 (dd, 3J(H,H)=8.0 Hz, 4J
ACTHNUTRGENNUG AHCUTNGTREN(NUGN H,H)=
1.1 Hz, 1H; nap 4-H), 7.50–7.37 (m, 3H; nap 2,6-H, TePh 4-H), 7.36–7.27
(m, 2H; TePh 3,5-H), 7.26–7.16 (m, 2H; SPh 3,5-H), 7.16–7.02 ppm (m,
4H; nap 3-H, SPh 2,4,6-H); 13C NMR (67.9 MHz, CDCl3, 258C, TMS):
d=141.0 (s), 139.6 (q), 138.3 (s), 137.0 (s), 136.3 (s), 134.9 (s), 132.1 (s),
130.4 (q), 129.8 (s), 129.1 (s), 128.7 (s), 127.9 (s), 127.4 (s), 127.0 (s), 126.1
(s), 125.8 (s), 123.4 (q), 118.3 ppm (s); 125Te NMR (81.2 MHz, CDCl3,
258C, PhTeTePh): d=715.2 ppm; 125Te NMR (81.2 MHz, D2SO4, 258C,
PhTeTePh): d=1018.3 ppm; IR (KBr disk): n˜max =3436 br, 3051 s, 2924 w,
1931 w, 1878 w, 1812 w, 1725 w, 1578 s, 1475 s, 1433 s, 1348 w, 1325 w,
1262 w, 1193 s, 1101 w, 1074 w, 1022 s, 995 w, 969 w, 898 w, 864 w, 811 vs,
758 s, 735 vs, 689 vs, 621 w, 539 s, 455 s, 405 cmÀ1 w; MS (ES+): m/z (%):
472.84 (100) [M+OMe]+; elemental analysis calcd (%) for C22H16STe: C
60.1, H 3.7; found: C 60.1, H 3.2.
1-(Phenylsulfinyl)-8-(phenylsulfanyl)naphthalene
(NapACTHNGURTENNU(G O=SPh)ACHTUNGTRENNUNG(SPh);
8): MCPBA (0.06 g, 0.34 mmol) was added to a solution of 1,8-(diphenyl-
sulfanyl)naphthalene (0.12 g, 0.34 mmol) in ether (5 mL). The reaction
mixture was stirred for 2 h and then concentrated under vacuum. Recrys-
tallisation by diffusion of pentane into a saturated solution of the com-
pound in dichloromethane gave the title compound as colourless crystals
(0.05 g, 41%). 1H NMR (270 MHz, CDCl3, 258C, TMS): d=8.75 (d, 3J-
A
ACHTUNGERTN(NUNG H,H)=8.0 Hz, 1H; nap 2-H),
A
ACHTUNGTRENNUNG
A
ACHTUNGTRENNUNG
3-H), 7.56–7.48 (m, 1H; nap 6-H), 7.48–7.40 (m, 2H; SOPh 2,6-H), 7.30–
7.20 (m, 3H; SOPh 3–5-H), 7.16–7.06 (m, 3H; SPh 3–5-H), 6.84–
6.74 ppm (m, 2H; SPh 2,6-H); 13C NMR (67.9 MHz, CDCl3, 258C, TMS):
d=139.0 (s), 132.9 (s), 131.4 (s), 130.3 (s), 129.2 (s), 129.1 (s), 127.2 (s),
127.1 (s), 126.7 (s), 126.3 (s), 126.1 ppm (s); IR (KBr disk): n˜max =3432
brs, 3057 w, 1576 s, 1546 w, 1492 w, 1475 s, 1439 s, 1353 w, 1336 w, 1202 w,
1173 w, 1156 w, 1079 s, 1036 vs, 971 w, 928 w, 902 w, 848 w, 820 vs, 763 vs,
736 vs, 682 vs, 595 w, 558 w, 518 s, 501 w, 471 s, 433 cmÀ1 s; MS (ES+):
m/z (%): 382.89 (100) [M+Na]+; elemental analysis calcd (%) for
C22H16S2O: C 73.3, H 4.5; found: C 72.2, H 5.2.>
Synthesis of 6 from 17: A solution of n-butyllithium (2.5m, 0.45 mmol) in
hexane (0.2 mL) was added dropwise to a solution of 1-iodo-8-(phenyl-
sulfanyl)naphthalene (0.16 g, 0.45 mmol) in diethyl ether (20 mL) at
À788C. The mixture was stirred at this temperature for 1 h, after which a
solution of diphenyl ditelluride (0.18 g, 0.45 mmol) in diethyl ether
(20 mL) was added dropwise to the mixture. The resulting mixture was
stirred at À788C for a further 1 h. The reaction mixture was washed with
0.1m sodium hydroxide (2ꢃ45 mL). The organic layer was dried with
magnesium sulfate, concentrated under reduced pressure and the residual
oil was purified by column chromatography on silica gel (hexane). Re-
crystallisation by diffusion of pentane into a saturated solution of the
compound in dichloromethane gave the title compound as yellow crystals
(0.2 g, 88%).
1,8-Bis(phenylsulfinyl)naphthalene (NapACTHNUTRGEN(UNG O=SPh)2; 9): MCPBA (0.18 g,
1.1 mmol) was added to a solution of 1,8-(diphenylsulfanyl)naphthalene
(0.12 g, 0.35 mmol) in ether (5 mL). The reaction mixture was stirred for
2 h, after which a white precipitate was formed. The mixture was filtered
and the filtrate reduced under vacuum to give a cream solid. Recrystalli-
sation by diffusion of pentane into a saturated solution of the compound
in dichloromethane gave the title compound as colourless crystals (0.06 g,
1-(Phenyltelluro)-8-(phenylselanyl)naphthalene (NapACTHNUTRGENNU(G TePh)CAHTUNGTRENN(UGN SePh); 7)
44%). 1H NMR (270 MHz, CDCl3, 258C, TMS) d=8.58 (dd, 3J
7.4 Hz, 4J(H,H)=1.4 Hz, 2H; nap 4,5-H), 8.13 (dd, 3J(H,H)=8.3 Hz, 4J-
(H,H)=1.4 Hz, 2H; nap 2,7-H), 7.83–7.74 (m, 2H; nap 3,6-H), 7.64–7.53
ACHTUNGTRENNUNG(H,H)=
Synthesis of 7 from 18: A solution of n-butyllithium (2.5m, 0.31 mmol) in
hexane (0.1 mL) was added dropwise to a solution of 1-bromo-8-(phenyl-
selanyl)naphthalene (0.11 g, 0.31 mmol) in diethyl ether (20 mL) at
À788C. The mixture was stirred at this temperature for 1 h, after which a
solution of diphenyl ditelluride (0.13 g, 0.31 mmol) in diethyl ether
(20 mL) was added dropwise to the mixture. The resulting mixture was
stirred at À788C for a further 1 h. The reaction mixture was washed with
0.1m sodium hydroxide (2ꢃ45 mL). The organic layer was dried with
magnesium sulfate, concentrated under reduced pressure and the residual
oil was purified by column chromatography on silica gel (hexane). Re-
crystallisation by diffusion of pentane into a saturated solution of the
compound in dichloromethane gave the title compound as yellow crystals
(0.1 g, 81%). 1H NMR (270 MHz, CDCl3, 258C, TMS): d=7.99 (dd, 3J-
N
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
(m, 4H; 2ꢃSOPh 2,6-H), 7.42–7.34 ppm (m, 6H; 2ꢃSOPh 3–5-H);
13C NMR (67.9 MHz, CDCl3, 258C, TMS): d=133.5 (s), 131.2 (s), 129.6
(s), 127.4 (s), 126.7 (s), 126.2 ppm (s); IR (KBr disk): n˜max =3445 brs,
3052 w, 1578 w, 1490 w, 1471 s, 1438 s, 1338 w, 1210 w, 1177 w, 1147 w,
1075 vs, 1045 vs, 996 w, 965 w, 911 w, 845 w, 823 vs, 753 vs, 690 vs, 621 s,
578 s, 503 s, 461 w, 438 s, 408 cmÀ1: w; MS (ES+): m/z (%): 398.84 (100)
[M+Na]+; elemental analysis calcd (%) for C22H16S2O2: C 70.2, H 4.3;
found: C 69.3, H 4.4.
Crystal structure analyses: X-ray crystal structures were determined at
À148(1)8C by using the St Andrews Robotic Diffractometer: a Rigaku
ACTOR-SM, Saturn 724 CCD area detector with graphite monochro-
mated MoKa radiation (l=0.71073 ꢀ). The data was corrected for Lor-
entz, polarisation and absorption. The data for the analysed complexes
was collected and processed by using CrystalClear (Rigaku).[33] The struc-
tures were solved by direct methods[34] and expanded by using Fourier
techniques.[35] The non-hydrogen atoms were refined anisotropically. Hy-
drogen atoms were refined by using the riding model. All calculations
were performed by using the CrystalStructure[36] crystallographic software
package except for refinement, which was performed by using SHELXL-
97.[37] Table 6 gives the crystallographic data for compounds 4–9.
CCDC-759109 (4), -759110 (5), -759111 (6), -759112 (7), -759113 (8) and
A
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
A
ACHTUNGTRENNUNG
2,6-H), 7.14–7.06 (m, 3H; TePh 3–5-H), 7.01 ppm (t, 3J
ACTHNUGRTENUNG(H,H)=7.7 Hz,
1H; nap 6-H); 13C NMR (67.9 MHz, CDCl3, 258C, TMS): d=140.4 (s),
139.7 (s), 136.0 (s), 131.8 (s), 130.2 (s), 129.7 (s), 129.3 (s), 128.5 (s), 128.2
(s), 126.8 (s), 126.7 (s), 125.9 ppm (s); 77Se NMR (51.5 MHz, CDCl3,
258C, PhSeSePh): d=362.8 ppm; 125Te NMR (81.2 MHz, CDCl3, 258C,
PhTeTePh): d=687.6 ppm (4J
N
=
7514
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ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 7503 – 7516

1,8-Chalcogen Naphthalene Derivatives
FULL PAPER
Table 6. Crystallographic data for compounds 4–6.
4
5
6
7
8
9
empirical formula
Mr
C14H16S2
248.4
C22H16SSe
391.39
C22H16STe
440.03
C22H16SeTe
486.93
C22H16OS2
360.49
C22H16O2S2
376.49
T [8C]
À148(1)
À148(1)
À148(1)
À148(1)
À148(1)
À148(1)
crystal colour, habit
colourless, prism colourless, block yellow, prism
yellow, prism
colourless, prism colourless, prism
crystal size [mm3]
crystal system
a [ꢀ]
0.15ꢃ0.09ꢃ0.09
orthorhombic
9.0074(15)
16.221(3)
17.386(3)
–
0.27ꢃ0.09ꢃ0.09
orthorhombic
21.150(5)
5.7154(12)
14.421(3)
–
0.18ꢃ0.15ꢃ0.12 0.21ꢃ0.09ꢃ0.09 0.18ꢃ0.09ꢃ0.09
triclinic
9.997(2)
11.2364(18)
17.928(3)
74.309(18)
87.24(2)
0.18ꢃ0.09ꢃ0.09
monoclinic
17.275(9)
15.216(7)
13.591(7)
–
105.593(11)
–
3441(3)
C2/c
triclinic
monoclinic
10.139(5)
15.379(6)
11.575(6)
–
111.083(15)
–
1684.0(14)
P21/c
10.094(4)
11.2590(19)
18.122(8)
73.66(4)
87.13(4)
67.06(3)
b [ꢀ]
c [ꢀ]
a [8]
b [8]
–
–
–
–
g [8]
66.344(13)
1771.7(6)
V [ꢀ3]
2540.2(8)
Pbca
8
1.299
1056
1743.3(7)
Pca21
4
1.491
792
1815.9(13)
¯
¯
space group
Z
P1
P1
4
1.65
864
4
4
8
1calc [gcmÀ3
]
1.781
936
1.422
752
1.453
1568
F
A
m
G
]
3.888
7639
0.076
0.942/0.966
2216
22.731
6528
0.063
0.397/0.815
2368
17.962
19899
0.032
0.718/0.806
7014
36.424
18410
0.05
0.461/0.720
6253
3.227
9709
0.054
0.943/0.971
3400
3.234
10825
0.059
0.961/0.981
3459
no. of reflns measured
Rint
min/max transmissions
indep. reflns
observed reflns (no. variables)
refln/parameter ratio
R1 (I>2.00s(I))
R (all reflns)
wR2 (all reflns)
1963 (148)
14.97
0.0764
0.0894
0.1333
1.245
–
0.24
À0.27
2217 (218)
10.86
0.0593
0.0655
0.1574
1.14
0.07(2)
0.67
À0.68
6663 (434)
16.16
0.0566
0.0599
0.1714
1.099
–
5691
(434)
3089
E
3114ACTHNGUTRENNU(G 236)
14.41
0.0646
0.0848
0.2886
1.211
–
14.98
0.0693
0.0789
0.167
1.169
–
14.66
0.0675
0.0808
0.1995
1.312
–
GOF
Flack parameter
max. peak in final diff. map [eꢀÀ3
]
]
1.64
À1.86
2.10
À2.27
0.34
À0.60
0.57
À0.55
min. peak in final diff. map [eꢀÀ3
-759114 (9) contain the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
this project was supported by the Engineering and Physical Sciences Re-
search Council (EPSRC). M.B. wishes to thank EaStCHEM for support.
Computational details: Geometries were fully optimised in the gas phase
at the B3LYP level[38] by using Curtis and Binningꢄs 962(d) basis[39] on Se
and 6-31+G(d) elsewhere, followed by calculation of the harmonic fre-
quencies to confirm the minimum character of each stationary point and
to obtain thermodynamic corrections. Reaction enthalpies (including
proton affinities (PAs)) and WBIs,[31] the latter obtained in a natural
bond orbital analysis,[40] are given at this level. If experimental structures
were available from X-ray crystallography, these were used as starting
point for the optimisations. Despite noticeable differences between calcu-
lated and optimised chalcogen–chalcogen distances (the optimised ones
tend to be overestimated by several picometers), essentially the same
WBIs were obtained for corresponding X-Ray and DFT structures. Mag-
netic shielding constants (s) were evaluated for the optimised minima at
the GIAO-B3LYP/II’ level, that is, by using contracted Huzinaga basis of
polarized triple-zeta quality,[41] except for the peripheral aromatic hydro-
gen atoms, for which a double-zeta (DZ) basis was employed. 77Se chemi-
cal shifts (d) are reported relative to Me2Se, computed at the same level
(d=1608 ppm). The computations were performed by using the Gaussi-
an 03 suite of programs.[41]
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Acknowledgements
The X-ray crystal structures were determined by Prof. Alexandra M. Z.
Slawin and Dr. Amy L. Fuller. Elemental analyses were performed by
Sylvia Williamson and mass spectrometry was performed by Caroline
Horsburgh. Calculations were performed by using the EaStCHEM Re-
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Received: December 22, 2009
Published online: May 12, 2010
7516
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Chem. Eur. J. 2010, 16, 7503 – 7516