Syntheses and X-ray crystal structures of poly(pyridylsulfanylmethyl)arenes: New multi-armed molecules

Article abstract of DOI:10.1016/S0040-4020(03)00550-7

The synthesis of a series of seven new poly(pyridylsulfanylmethyl)arenes is reported. These are readily prepared from either 2- or 4-mercaptopyridine and a poly(bromomethyl)arene in the presence of triethylamine. Compounds with three, four, six and eight pyridylsulfanylmethyl arms are reported. These have been fully characterised and, in four cases, the relative orientations of the pyridylsulfanylmethyl arms have been ascertained by X-ray structural analysis.

Full text of DOI:10.1016/S0040-4020(03)00550-7

Tetrahedron 59 (2003) 3701–3707
Syntheses and X-ray crystal structures of
poly(pyridylsulfanylmethyl)arenes: new multi-armed molecules
*
David A. McMorran and Peter J. Steel
Department of Chemistry, University of Canterbury, Christchurch, New Zealand
Received 3 January 2003; revised 25 March 2003; accepted 4 April 2003
Abstract—The synthesis of a series of seven new poly(pyridylsulfanylmethyl)arenes is reported. These are readily prepared from either 2- or
4-mercaptopyridine and a poly(bromomethyl)arene in the presence of triethylamine. Compounds with three, four, six and eight
pyridylsulfanylmethyl arms are reported. These have been fully characterised and, in four cases, the relative orientations of the
pyridylsulfanylmethyl arms have been ascertained by X-ray structural analysis. q 2003 Elsevier Science Ltd. All rights reserved.
1. Introduction
can do this is determined by the nature, and number, of the
donor groups built into the arms, the number and relative
arrangement of the arms about the core unit, and by the
electronic and structural requirements of the metal ion in
question.
Over recent years there have been an increasing number of
reports of so-called ‘multi-armed’ molecules. This term
describes molecules in which a core unit, most often an
aromatic ring(s), is appended by a number of long, semi-
rigid or flexible, aromatic and/or aliphatic chains (the
‘arms’). The number of arms depends on the nature of the
core unit: for example, a benzene core unit can accommo-
date up to six arms. While such molecules can be
synthetically challenging, as there may be considerable
steric resistance to attaching, for example, six arms around a
benzene ring, an increasing number of multi-armed
molecules are appearing in the literature, often with
names reflecting the shapes, e.g. asterisk molecules,1
octopus ligands,2 and spider hosts.3
An important consideration in the design of such com-
pounds is how the arms will arrange themselves about the
core unit. Various studies have shown that the most
favoured arrangement, on steric grounds, is one where all
adjacent arms are on opposite sides of the plane of the core
unit,8,9 and this pre-organisation of the arms has been
utilized by a number of groups.10
We report here the preparation and characterisation of a
series of new multi-armed molecules, which we have
prepared as a part of our studies into the effects on metal
ion coordination of incorporating flexibility into poly-
heterocyclic N-donor ligands.11 The new molecules each
contain an arene core, to which are appended three, four, six
or eight pyridylsulfanylmethyl arms, and are shown in
Figure 1.12,13 Compound 8 represents a rare example of a
multi-armed molecule incorporating a biphenylene core
platform.
Such molecules are of interest in a range of contexts. For
example, multi-armed molecules, in which an aromatic core
is appended by long aliphatic arms, find uses as discotic
liquid crystals.4 In particular, triphenylene, appended by six
arms, is becoming widely used as a core in such molecules.5
Benzene cores appended by six flexible arms, each
terminated by an anionic group, have recently been shown
to form micelles in aqueous solutions.1 Other systems
containing naphthalene core units have been shown to act as
hosts for a range of solvent molecules.3 Multi-armed arenes
have also been frequently used as core units for dendri-
mers.6 To a lesser extent, multi-armed molecules, in which
the arms contain suitable donor functionalities, have been
used as ligands for metal ions.7 The manner in which they
We also report here the X-ray crystal structures of four of
these compounds, namely 1,3,5-tris(2-pyridylsulfanyl-
methyl)-2,4,6-trimethylbenzene (1), 1,2,4,5-tetrakis(2-
pyridylsulfanylmethyl)benzene (3), hexakis(4-pyridylsul-
fanylmethyl)benzene (7) and octakis(2-pyridylsulfanyl-
methyl)biphenylene (8). These show that, in three of the
four cases, the arms are arranged in the sterically preferred
arrangement, i.e. alternating above and below the central
arene platform, whereas in the case of 3, the arms adopt a
different arrangement in the solid state.
Keywords: multi-armed molecules; biphenylene; X-ray structures.
*
Corresponding author. Tel.: þ64-3-479-7934; fax: þ64-3-476-7906;
e-mail: davidm@alkali.otago.ac.nz
0040–4020/03/$ - see front matter q 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0040-4020(03)00550-7

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D. A. McMorran, P. J. Steel / Tetrahedron 59 (2003) 3701–3707
spectroscopy, in either CDCl3 or, where necessary,
DMSO-d6. Assignment of the pyridine ring protons was
confirmed by 1-D TOCSY experiments. In the case of 5, the
1H NMR spectrum shows two sets of CH2-pyridyl ring
signals, due to the ‘outer’ (C1 and C4) and ‘inner’ (C2 and
C3) arms. Assignment of these was achieved by a 1-D nOe
experiment, where irradiation of the CH2 peaks gave
0
observable enhancements of their adjacent pyridine H3
peaks, whereas only irradiation of the CH2 peak at 4.56 ppm
gave an enhancement to the central benzene ring protons H5
and H6, showing that this peak corresponds to the methylene
groups of the ‘outer’ arms.
The synthesis of 8 is outlined in Scheme 2. Prehnitene was
dibrominated14 and then treated with n-butyllithium in
anhydrous THF to give octamethylbiphenylene.15 A free-
radical bromination of this using an excess of N-bromo-
succinimide, in the presence of dibenzoyl peroxide, gave
octakis(bromomethyl)biphenylene as a bright yellow solid.
EI-MS and 1H NMR spectra confirmed the presence of
the desired product. Reaction of octakis(bromomethyl)bi-
phenylene with 2-mercaptopyridine proceeded cleanly and
the resulting solid could be purified by recrystallisation from
chloroform–diethyl ether solutions. The 1H NMR spectrum
showed two sets of peaks, due to the ‘inner’ and ‘outer’
arms, as was observed for 5. These were assigned by 1-D
TOCSY experiments and by comparison of the peak
positions with those for 5: one set of peaks has almost the
same positions in both cases, while each signal of the second
set lies about 0.3 ppm upfield in the spectrum of 8,
compared to that of 5.
Figure 1.
2. Results and discussion
The new compounds were prepared from the appropriate
poly(bromomethyl)arene by treatment with either 2- or
4-mercaptopyridine and triethylamine in cold acetonitrile
solution (Scheme 1). They were isolated as pale-coloured
solids in moderate to good yields and their constitutions
confirmed by microanalysis and by electrospray mass
spectrometry of their protonated adducts. In each case, the
4-pyridyl isomer was much less soluble than the 2-pyridyl
and, interestingly, the solubility of 3 was found to be much
poorer than that of the less symmetrical isomer 5.
The two sets of peaks whose positions are invariant are
those which, in the spectrum of 5, are assigned to the inner
arms. As it is these which might be expected to enjoy the
most similar environment in both 5 and 8, we assign these in
The compounds were also characterised by 1H NMR
Scheme 1.
Scheme 2. (i) Br2, cat. I2, CH3COOH; (ii) BunLi, THF, 280 8C–RT; (iii) NBS, (PhCO)2O2, CCl4, hn, reflux; (iv) 2-pySH, Et3N, MeCN, 0 8C–RT.

D. A. McMorran, P. J. Steel / Tetrahedron 59 (2003) 3701–3707
3703
this way. The second set of peaks, which shift upfield in the
case of 8, are then assigned to the outer arms, which, in the
case of 8, lie adjacent not only to one of the inner arms, as in
the case of 5, but also now to one of the arms in the peri
position. The proximity of this second arm may result in the
pyridine rings of the two arms interacting via a p-stacking
interaction, which would in turn explain the upfield shifts
observed for the peaks. The X-ray crystallographic analysis
of 8, discussed below, supports this proposal.
pyridine ring of an adjacent molecule (closest inter-ring
˚
distance 3.45 A, angle between ring meanplanes 6.68). The
molecules further interact via a (weak) CH· · ·N hydrogen
bond between a pyridine nitrogen on one arm and an
aromatic CH on an arm of an adjacent molecule (N· · ·C
˚
3.44 A, N· · ·H–C 172.78).
Crystals of 3, suitable for X-ray analysis, were obtained
from an acetonitrile solution. Figure 3 shows a perspective
view of the structure, which crystallizes in the triclinic space
group P-1. The asymmetric unit contains half a molecule of
3 and a crystallographic centre of inversion lies at the centre
of the benzene ring.
Four of the compounds, 1, 3, 7 and 8 were structurally
characterised by X-ray crystallography. The structures of
the new multi-armed molecules are of interest because, in
each case, there are a number of structural forms possible,
depending on the relative arrangement of the arms. The
most favoured arrangement, based on steric arguments, has
the arms alternating above and below the central arene
platform.8 Studies on related compounds comprising
multiple arms have shown that this is usually the observed
arrangement in such species, although other arrangements
can be found in, for example, metal complex adducts.16
The arms, in this case, adopt an abba arrangement, with the
pyridine rings lying at angles of 75.28 (N11–C16) and 76.18
(N21–C26) to the central benzene ring. Although adjacent
arms lie on opposite sides of the central benzene ring, one of
the arms adopts an anti conformation about the CH2–S
bond while the other arm has a gauche arrangement. This
difference in orientation of the arms affects the inter-
molecular interactions between them. Consideration of the
molecular packing shows that the rings that are involved in
the gauche arrangement of the arms experience inter-
molecular p-stacking interactions, with a closest inter-ring
Crystals of 1 suitable for X-ray analysis were obtained by
diffusion of petroleum ether into a chloroform solution.
Figure 2 shows a perspective view of the structure, which
crystallizes in the monoclinic space group P21/n. The
asymmetric unit contains a whole molecule of 1. The arms
all adopt an anti geometry about the CH2–S bonds and are
arranged about the central benzene ring in the less hindered
aba orientation,17 with the pyridine rings lying at angles of
80.38 (N11–C16), 93.18 (N31–C36) and 84.08 (N51–C56)
to the central benzene ring.
˚
distance of 3.59 A. Surprisingly, there are no intermolecular
hydrogen bonding interactions in this case.
Crystals of 7, suitable for X-ray analysis, were obtained
from a pyridine solution. Figure 4 shows a perspective view
of the structure, which crystallizes in the monoclinic space
group P21/c. The asymmetric unit contains half a molecule
of 7 and half a diethyl ether solvate molecule. A crystal-
lographic centre of inversion lies at the centre of the
benzene ring. The arms all adopt an anti geometry about the
CH2–S bonds and are arranged about the central benzene
ring in the sterically most favoured ababab orientation, with
the pyridine rings lying almost orthogonal to the central
benzene ring: the angles between the mean planes are 92.88
(N11–C16), 66.98 (N21–C26) and 85.18 (N31–C36).
The molecules pack in the crystal with the central benzene
ring of one molecule forming a p-stacking interaction with a
Consideration of the molecular packing shows that the
molecules are held together by a variety of intermolecular
interactions. Two sets of hydrogen bonding interactions are
present, between, in each case, a pyridine nitrogen and an
aromatic CH group. The stronger of these has an N· · ·C
˚
distance of 3.416 A and an N· · ·H–C angle of 168.38. There
are also strong p-stacking interactions between pyridine
rings in adjacent molecules, with a closest intermolecular
˚
C· · ·C distance of 3.37 A. Finally, there are relatively strong
18
˚
intermolecular S· · ·S interactions at a distance of 3.57 A.
These interactions hold the molecules together in such a
way as to generate channels, which run parallel to the c axis,
within which the diethyl ether solvate molecules reside.
Crystals of 8, suitable for X-ray analysis, were obtained by
diffusing diethyl ether into a chloroform solution. Figure 5
shows a perspective view of the structure, which crystallizes
in the orthorhombic space group Ccca. The asymmetric unit
contains one quarter of a molecule of 8 and half a diethyl
ether solvate molecule. Three mutually orthogonal two-fold
rotation axes intersect at the centre of the central C4 ring of
the biphenylene core, generating the complete structure
Figure 2. Perspective view of the structure of 1, showing the crystal-
lographic labeling.

3704
D. A. McMorran, P. J. Steel / Tetrahedron 59 (2003) 3701–3707
Figure 3. Perspective view of the structure of 3, showing the crystallographic labeling.
with D2 symmetry. The arms all adopt an anti geometry
about the CH2–S bonds and adopt the least hindered
abababab arrangement about the central biphenylene core.
The pyridine rings are almost orthogonal to the central
biphenylene core, with angles between the mean planes of
87.88 (N21–C26) and 90.58 (N31–C36).
described above. The pattern of bond lengths and angles
within the biphenylene core (Fig. 5) parallels those observed
in other structurally characterised octa-substituted biphenyl-
enes.9,19 These have been interpreted to suggest that there is
bond localisation in these molecules.19,20
Consideration of the molecular packing reveals columns,
containing molecules of 8 and disordered diethyl ether
solvate molecules alternately, which stack parallel to the c
axis. These columns lie offset from each other, in a manner
such that the ‘inner’ arms in adjacent columns interdigitate
and form intermolecular hydrogen bonding interactions
Despite lying on opposite sides of the biphenylene core,
pairs of adjacent ‘outer’ arm pyridine rings experience
intramolecular p-stacking interactions with each other, with
a closest C· · ·C distance of 3.60 A. This provides good
support for the justification of the 1H NMR assignment of 8,
˚
Figure 4. Perspective view of the structure of 7, showing the crystallographic labeling. The diethyl ether solvate molecule is omitted for clarity.

D. A. McMorran, P. J. Steel / Tetrahedron 59 (2003) 3701–3707
3705
Figure 5. Perspective view of the structure of 8, showing the crystallographic labeling. The diethyl ether solvate molecule is omitted for clarity. Selected bond
˚
lengths (A) and angles (8). C1–C2 1.365 (3), C1–C1A 1.413 (4), C1–C1B 1.516 (4), C2–C3 1.438 (3), C1A–C1–C2 123.4 (1), C1–C2–C3 115.0 (2).
between pyridine nitrogens and aromatic CH units. All of
the hydrogen bonds are the same and have an N· · ·C
˚
distance of 3.549 A and an N· · ·H–C angle of 145.98. The
All the compounds were prepared in the same way. The
preparation of 1 is given as a general procedure.
diethyl ether solvate, which lies in cavities formed between
the two 8 molecules above and below it in the column and
the 8 molecules which lie in the adjacent columns, are held
in place by a number of O· · ·H and S· · ·H interactions.
X-Ray crystallography. All measurements were made with a
Siemens CCD area detector using graphite monochroma-
˚
tised Mo Ka (l¼0.71073 A) radiation. Intensities were
corrected for Lorentz and polarisation effects and for
absorption. The structures were solved by direct methods
using SHELXS,24 and refined on F2 using all data by full-
matrix least-squares procedures with SHELXL-97.25 All
non-hydrogen atoms were refined with anisotropic displace-
ment parameters. Hydrogen atoms were included in
calculated positions with isotropic displacement parameters
1.3 times the isotropic equivalent of their carrier carbons.
The functions minimised were SwðFo2 2 Fc2Þ; with w ¼
This structure provides an interesting contrast to that of
octaethylbiphenylene, the only other crystallographically
characterised example of a multi-armed, biphenylene-cored
molecule.9 In this case, where the arms are substantially
smaller than those in 8, the molecule was found to adopt an
ababbaba arrangement, with C2 h symmetry, in the solid
state. However, this was proposed to be due to crystal
packing forces and the lower energy abababab arrangement
was found in solution.
2
½s2ðFo2Þ þ aP2 þ bPꢀ21; where P ¼ ½maxðFoÞ þ 2Fc2ꢀ=3:
Crystallographic data (excluding structure factors) for the
structures in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication numbers CCDC No. 194768, 194769, 194770
and 194771. Copies of the data can be obtained, free of
charge, on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: þ44-1223-336033 or
e-mail: deposit@ccdc.cam.ac.uk).
3. Experimental
3.1. General procedures
Compound 3 was prepared as described previously.13
Octamethylbiphenyl,15 1,3,5-tris(bromomethyl)-2,4,6-tri-
methylbenzene,21 1,2,4,5-tetrakis(bromomethyl)benzene,22
1,2,3,4-tetrakis(bromomethyl)benzene,22 and hexakis-
(bromomethyl)benzene23 were prepared by literature pro-
cedures. 2- and 4-Mercaptopyridine were purchased from
Aldrich and used as received. Melting points are uncorrected.
NMR spectra were recorded on Varian 500 or 300 MHz NMR
spectrometers. ES-MS spectra were recorded using a Micro-
mass LCT TOF mass spectrometer. EI-MS spectra were
recorded on a Kratos MS80RFA spectrometer. Elemental
analyses were performed by the Campbell Microanalytical
Laboratory at the University of Otago.
3.1.1. Preparation of 1,3,5-tris(2-pyridylsulfanylmethyl)-
2,4,6-trimethylbenzene (1). 1,3,5-Tris(bromomethyl)-
2,4,6-trimethylbenzene (1.78 g, 4.48 mmol) and 2-mercap-
topyridine (1.49 g, 13.4 mmol) were stirred in acetonitrile
(50 mL) at 0 8C. Triethylamine (1.69 g, 16.8 mmol) was
added via syringe and the solution stirred overnight, slowly
warming to room temperature. The resulting pale brown
precipitate was filtered off, washed with water, acetonitrile
and diethyl ether and dried. Recrystallization from hot
acetonitrile gave 1 as a white crystalline solid. Yield: 1.41 g

3706
D. A. McMorran, P. J. Steel / Tetrahedron 59 (2003) 3701–3707
(64%). Mp: 179–180 8C. 1H NMR (CDCl3, 500 MHz, ppm)
d 2.50 (s, 9H, CH3), 4.50 (s, 6H, CH2), 7.00 (dd, J¼5, 7 Hz,
topyridine gave the product, which was recrystallized from
dimethylformamide solution as a white microcrystalline
1
0
0
3H, H5 ), 7.19 (d, J¼7 Hz, 3H, H3 ), 7.48 (t, J¼7 Hz, 3H,
solid. Yield: 81%. Mp: 224–226 8C. H NMR (DMSO-d6,
500 MHz, ppm) d 4.62 (s, 12H, CH2), 7.02 (dd, J¼7.5, 5 Hz,
0
0
H4 ), 8.48 (d, J¼5 Hz, 3H, H6 ). HR ES-MS (CH3CN/
HCOOH): 490.1451. Required for [C27H27N3S3·H]þ
490.1445. Analysis. C27H27N3S3 requires: C, 66.22; H,
5.56; N, 8.58. Found: C, 66.17; H, 5.57; N, 8.48.
0
0
6H, H5 ), 7.27 (d, J¼7.5 Hz, 6H, H3 ), 7.59 (t, J¼7.5 Hz, 6H,
0
0
H4 ), 8.05 (d, J¼5 Hz, 6H, H6 ). ES-MS (CH3CN/HCOOH):
817.2 [M·H]þ, 409.1 [M·2H]2þ. Analysis. C42H36N6S6
requires: C, 61.72; H, 4.44; N, 10.28. Found: C, 61.48; H,
4.42; N, 10.34.
X-Ray structural analysis of 1: formula C27H27N3S3,
M¼489.70, colourless crystal 0.75£0.70£0.05 mm3,
˚
a¼16.335(6), b¼10.087(4), c¼16.939(6) A, b¼
3.1.7. Hexakis(4-pyridylsulfanylmethyl)benzene (7).
Reaction of hexakis(bromomethyl)benzene and 4-mercap-
topyridine gave the product which was recrystallized by
diffusion of petroleum ether (50–70) into a pyridine
solution as colourless plates. Yield: 90%. Mp: 205–
118.223(4)8, V¼2459.1(15), rcalcd¼1.323 g cm21, Z¼4,
monoclinic, P21/n, T¼168(2) K, 2umax¼53.08, 30408
reflections collected, 5034 unique, 3006 observed,
R1¼0.0440, wR2¼0.1067.
1
207 8C. H NMR (CDCl3, 500 MHz, ppm) d 4.39 (s, 12H,
0
0
3.1.2. 1,3,5-Tris(4-pyridylsulfanylmethyl)-2,4,6-tri-
methylbenzene (2). Reaction of 1,3,5-tris(bromomethyl)-
2,4,6-trimethylbenzene and 4-mercaptopyridine gave the
product, which was recrystallised from hot acetonitrile as
white needles. Yield: 72%. Mp: 229–231 8C. 1H NMR
(CDCl3, 500 MHz, ppm) d 2.48 (s, 9H, CH3), 4.25 (s, 6H,
CH2), 7.05 (d, J¼5 Hz, 12H, H3 , H5 ), 8.36 (d, J¼5 Hz,
0 0
12H, H2 , H6 ). HR ES-MS (CH3CN/HCOOH): 817.1409.
Required for [C42H36N6S6·H]þ 817.1404. Analysis.
C42H36N6S6 requires: C, 61.72; H, 4.44; N, 10.28. Found:
C, 61.78; H, 4.79; N, 10.61.
0
0
CH2), 7.17 (d, J¼5 Hz, 6H, H3 , H5 ), 8.44 (d, J¼5 Hz, 6H,
X-Ray structural analysis of 7: formula C44H41N6S6O0.5,
M¼854.19, colourless crystal 0.25£0.25£0.15 mm3,
106.007(19)8, V¼2299(2), rcalcd¼1.234 g cm21, Z¼2,
monoclinic, P21/c, T¼168(2) K, 2umax¼53.08, 21965
reflections collected, 4676 unique, 2484 observed,
R1¼0.0466, wR2¼0.1230.
0
0
H2 , H6 ). HR EI-MS: 489.13672. Required for C27H27N3S3
489.13671. Analysis. C27H27N3S3·1/2H2O requires: C,
65.09; H, 5.66; N, 8.42. Found: C, 65.44; H, 5.59; N, 8.55.
˚
a¼13.117(7), b¼20.574(12), c¼8.862(5) A, b¼
3.1.3. 1,2,4,5-Tetrakis(2-pyridylsulfanylmethyl)benzene
(3).13 X-Ray structural analysis of 3: formula C30H26N4S4,
M¼570.70, colourless crystal 0.60£0.26£0.05 mm3, a¼
˚
8.349(4), b¼8.748(4), c¼11.136(6) A, a¼86.575(8), b¼
3.1.8. Octakis(2-pyridylsulfanylmethyl)biphenylene (8).
Octamethylbiphenylene (50 mg, 0.19 mmol) and N-bromo-
succinimide (541 mg, 3.04 mmol) were brought to reflux in
CCl4 (15 mL). Dibenzoyl peroxide (5 mg) was added and
the solution irradiated for 2.5 hours to give a bright yellow
suspension. This was cooled and the solvent removed. The
yellow residue was suspended in acetone and filtered,
washed with acetone and diethyl ether and dried. Yield:
74 mg (43%). 1H NMR (DMSO-d6, 500 MHz, ppm) d 4.71
(s, 8H, CH2 in/out), 4.78 (s, 8H, CH2 in/out)). EI-MS m/z 895
[M]þ, 814 [M2Br]þ, 737 [M22Br]þ, 657 [M23Br]þ, 579
[M24Br]þ, 497 [M25Br]þ, 419 [M26Br]þ. Analysis.
C20H16Br8 requires: C, 26.82; H, 1.80. Found: C, 27.08; H,
68.313(5), g¼63.466(6)8, V¼670.7(5), rcalcd¼1.413
g cm21, Z¼1, triclinic, P-1, T¼168(2) K, 2umax¼53.08,
8586 reflections collected, 2683 unique, 2077 observed,
R1¼0.0362, wR2¼0.0852.
3.1.4. 1,2,4,5-Tetrakis(4-pyridylsulfanylmethyl)benzene
(4). Reaction of 1,2,4,5-tetrakis(bromomethyl)benzene and
4-mercaptopyridine gave the product, which was recrystal-
lized by diffusing diethyl ether into a chloroform solution.
Yield: 50%. Mp: 192–193 8C. 1H NMR (DMSO-d6,
500 MHz, ppm) d 4.45 (s, 8H, CH2), 7.26 (d, J¼5 Hz, 8H,
0
0
0
0
H3 , H5 ), 7.56 (s, 2H, H3, H6), 8.32 (d, br, 8H, H2 , H6 ). HR
ES-MS (CH3CN/HCOOH): 571.1118. Required for
[C30H26N4S4·H]þ 571.1119. Analysis: C30H26N4S4·1/
4CHCl3 requires: C, 60.48; H, 4.41; N, 9.32. Found: C,
60.20, H, 4.29; N, 9.18.
1.89.
Octakis(bromomethyl)biphenylene
(100 mg,
0.11 mmol) was reacted with 2-mercaptopyridine (109 mg,
0.98 mmol), as above, to give the product as a yellow solid.
Yield: 91 mg (71%). Mp: 195–197 8C. Diffusion of diethyl
ether into a chloroform solution gave deep yellow needles.
1H NMR (CDCl3, 500 MHz, ppm) d 4.45 (s, 8H, CH2 in),
3.1.5. 1,2,3,4-Tetrakis(2-pyridylsulfanylmethyl)benzene
(5). Reaction of 1,2,3,4-tetrakis(bromomethyl)benzene and
2-mercaptopyridine gave the product, which was recrystal-
lized from acetone/ethanol solution at 0 8C. Yield: 50%.
Mp: 80–81 8C. 1H NMR (CDCl3, 500 MHz, ppm) d 4.56 (s,
4H, CH2 out), 4.76 (s, 4H, CH2 in), 6.89 (dd, J¼7, 5 Hz, 2H,
0
4.57 (s, 8H, CH2 out), 6.74 (dd, J¼7.5, 5 Hz, 4H, H5 in), 6.82
0
0
(dd, J¼7.5, 5 Hz, 4H, H5 out), 6.97 (d, J¼7.5 Hz, 4H, H3 in),
0
0
7.09 (d, 7.5 Hz, 4H, H3 out), 7.25 (t, J¼7.5 Hz, 4H, H4 in),
0
0
7.37 (t, J¼7.5 Hz, 4H, H4 out), 7.92 (d, J¼5 Hz, 4H, H6 in),
0
8.06 (d, J¼5 Hz, 4H, H6 out). ES-MS (CH3CN/HCOOH)
H5 in), 6.93 (dd, J¼7, 5 Hz, 2H, H5 out), 7.12 (m, 4H,
1137.0 [M·H]þ. Analysis. C60H48N8S8 requires: C, 61.40;
H, 4.46. Found: C, 61.46; H, 5.07.
0
0
0
H3 in,out), 7.33 (s, 2H, H5, H6), 7.42 (m, 4H, H4 in,out), 8.21
0
0
0
(d, J¼5 Hz, H6 in), 8.35 (d, J¼5 Hz, 2H, H6 out). HR ES-MS
(CH3CN/HCOOH):
571.1117.
Required
for
X-Ray structural analysis of 8: formula C67H65N8S8O2,
M¼1270.75, colourless crystal 0.60£0.30£0.30 mm3,
[C30H26N4S4·H]þ 571.1119. Analysis. C30H26N4S4 requires:
C, 63.12; H, 4.59; N, 9.81. Found: C, 62.84; H, 4.80; N, 9.69.
˚
a¼22.217(6), b¼25.718(8), c¼11.618(3) A, V¼6638(3),
rcalcd¼1.271 g cm21
,
Z¼4, orthorhombic, Ccca,
3.1.6. Hexakis(2-pyridylsulfanylmethyl)benzene (6).
Reaction of hexakis(bromomethyl)benzene and 2-mercap-
T¼168(2) K, 2umax¼53.08, 23257 reflections collected,
3385 unique, 2134 observed, R1¼0.0416, wR2¼0.1190.

D. A. McMorran, P. J. Steel / Tetrahedron 59 (2003) 3701–3707
3707
S.; Steel, P. J. Inorg. Chem. Commun. 2002, 5, 449–451.
(d) Steel, P. J.; Sumby, C. J. Chem. Commun. 2002, 322–323.
(e) Fitchett, C. M.; Steel, P. J. Inorg. Chim. Acta 2000, 310,
127–132.
Acknowledgements
We thank the Royal Society of New Zealand Marsden Fund
for financial support and Dr Christopher M. Hartshorn for
some preliminary results.
12. Note that 3, 5 and 6 have been mentioned in Ref. 2. However,
with the exception of a melting point for 6, no experimental
details, characterization or chemistry of these was reported.
13. The preparation of 3 has been reported previously by our
group Hartshorn, C. M.; Steel, P. J. J. Chem. Soc., Dalton
Trans. 1998, 3935–3940.
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