Synthesis and complexation of nickel(II) and copper(II) by pendant-arm alcohol derivatives of [9]aneNS2 (7-aza-1,4-dithiacyclononane)

Article abstract of DOI:10.1039/a804303e

A simplified procedure for the preparation of [9]aneNS₂ (7-aza-1,4-dithiacyclononane) is described. The structure of the complex [Cu([9]aneNS₂)₂]²⁺ confirms that the CU(II) centre is in a distorted octahedral environment, Cu-S(1) 2.5469(14), Cu-S(4) 2.5386(13), Cu-N(7) 2.016(4) A. Reaction of [9]aneNS₂ with isobutylene oxide or 2,2-diphenyl-oxirane gives the alcohol derivatives, HL¹ and HL², respectively. The 1:1 metal:ligand complex [Cu₂(L¹)₂]²⁺ was found to be binuclear with the alcohol functions deprotonated to form alkoxide bridges between two CU(II) centres, Cu-N(1) 2.042(4), Cu-S(4) 2.452(2), Cu-S(7) 2.430(2), Cu-O(14) 1.927(4), Cu-O(14′) 1.922(4), Cu-Cu′ 3.0063(9) A, Cu-O-Cu′ 102.7(2)°. Magnetochemical data for this complex confirm antiferromagnetic coupling between the two Cu(II) centres with 2J = -417 ± 2 cm^-1. With Ni(II) the complex [Ni(HL¹)(CH₃CO₂)]⁺ can be isolated, the structure of which shows it to be a monomer with the ligand HL¹ acting as a tetradentate ligand to the metal centre, Ni-N(1) 2.064(3), Ni-S(4) 2.3658(12), Ni-S(7) 2.3875(13), Ni-O(14) 2.061(3) A. A chelating acetate ligand completes the distorted octahedral geometry, Ni-O(16) 2.098(3), Ni-O(17) 2.102(3) A.

Full text of DOI:10.1039/a804303e

View Article Online / Journal Homepage / Table of Contents for this issue
Synthesis and complexation of nickel(II) and copper(II) by
pendant-arm alcohol derivatives of [9]aneNS2 (7-aza-1,4-
dithiacyclononane)
Alexander J. Blake,a Jonathan P. Danks,a Ian A. Fallis,b Andrew Harrison,b Wan-Sheung Li,a
Simon Parsons,b Steven A. Ross,b Gavin Whittakerb and Martin Schröder*a
a School of Chemistry, The University of Nottingham, University Park, Nottingham,
UK NG7 2RD
b Department of Chemistry, The University of Edinburgh, Edinburgh, UK EH9 3JJ
Received 8th June 1998, Accepted 7th September 1998
A simplified procedure for the preparation of [9]aneNS2 (7-aza-1,4-dithiacyclononane) is described. The structure
of the complex [Cu([9]aneNS2)2]2ϩ confirms that the Cu() centre is in a distorted octahedral environment, Cu–S(1)
2.5469(14), Cu–S(4) 2.5386(13), Cu–N(7) 2.016(4) Å. Reaction of [9]aneNS2 with isobutylene oxide or 2,2-diphenyl-
oxirane gives the alcohol derivatives, HL1 and HL2, respectively. The 1:1 metal:ligand complex [Cu2(L1)2]2ϩ was
found to be binuclear with the alcohol functions deprotonated to form alkoxide bridges between two Cu() centres,
Cu–N(1) 2.042(4), Cu–S(4) 2.452(2), Cu–S(7) 2.430(2), Cu–O(14) 1.927(4), Cu–O(14Ј) 1.922(4), Cu–CuЈ 3.0063(9) Å,
Cu–O–CuЈ 102.7(2)Њ. Magnetochemical data for this complex confirm antiferromagnetic coupling between the two
Cu() centres with 2J = Ϫ417 2 cmϪ1. With Ni() the complex [Ni(HL1)(CH3CO2)]ϩ can be isolated, the structure
of which shows it to be a monomer with the ligand HL1 acting as a tetradentate ligand to the metal centre, Ni–N(1)
2.064(3), Ni–S(4) 2.3658(12), Ni–S(7) 2.3875(13), Ni–O(14) 2.061(3) Å. A chelating acetate ligand completes the
distorted octahedral geometry, Ni–O(16) 2.098(3), Ni–O(17) 2.102(3) Å.
fewer steps.9 We have modified the procedure for the syn-
thesis of [10]aneNS2 and used it for the synthesis of [9]aneNS2
Introduction
1
2
The co-ordination chemistry of [9]aneN3 and [9]aneS3 has
been thoroughly investigated over recent years. The mixed-
donor analogue [9]aneN2S has also been the subject of
extended study,3–5 particularly by Mattes and co-workers.6 In
contrast however, the co-ordination chemistry and functional-
isation of [9]aneNS2, which completes the homologous group
of nine-membered N/S-donor macrocycles, is by far the least
studied.3 This is due to the synthetic difficulties and costs
encountered in the synthesis of the ligand itself. Derivatives
of [9]aneNS2 incorporating monodentate donors would be
expected to form potentially four-co-ordinate, unsaturated
complexes in the absence of additional ligands.
thereby simplifying the overall synthesis of this macrocyclic
system.
Ligand synthesis
The synthesis of [9]aneNS2 was accomplished via a modific-
ation of the three-step route reported for [10]aneNS2 (Scheme
1).9 Reaction of diethanolamine with p-toluenesulfonyl chlor-
We report herein a simplified synthesis of [9]aneNS2 (7-aza-
1,4-dithiacyclononane) and its bis-sandwich Cu() complex
[Cu([9]aneNS2)2]2ϩ. The reaction of [9]aneNS2 with isobutylene
oxide or 2,2-diphenyloxirane to give pendant arm alcohol
derivatives HL1 and HL2 and complexes with Cu() and Ni()
are also reported.
Results and discussion
The synthesis of 7-aza-1,4-dithiacyclononane, [9]aneNS2, was
first reported by both Parker7 and McAuley8 independently
in 1990. Whilst the ring-closure step for both [9]aneN3 and
[9]aneN2S does not require high-dilution techniques to avoid
appreciable polymerisation, this is not the case for [9]aneNS2
and [9]aneS3, which both involve the addition of the reactants
over several hours into a large volume of solvent. Both routes
employed by these workers were essentially the same differing
only in the final detosylation step. McAuley reported difficulty
in this step and finally used phosphoric acid to afford the
product macrocycle in 50% yield.8 Parker and co-workers opted
for deprotection using HBr–acetic acid and reported a yield
of 73% for the deprotection step. McAuley has since reported
the synthesis of [10]aneNS2 via an alternative route requiring
Scheme 1
ide in triethylamine at 0 ЊC gives the corresponding tritosylate
in 81% yield. A solution of the tritosylate and ethane-1,2-
dithiol in DMF was added over a period of 12 h to a suspension
of Cs2CO3 in DMF under high-dilution conditions. This is
followed by a further addition of Cs2CO3 to the reaction mix-
ture, followed by another slow addition of a solution of
the tritosylate and ethane-1,2-dithiol in DMF over 12 h. The
ring-closure step proceeds typically in 32% yield in our hands.
J. Chem. Soc., Dalton Trans., 1998, 3969–3976
3969

View Article Online
Table 1 Selected bond lengths (Å) and angles (Њ) for [Cu([9]aneNS2)2]-
[PF6]2
Detosylation was carried out according to Parker and co-
workers7 using HBr–acetic acid2 and subsequent base extrac-
tion affords the free cyclic amine as a white solid in 78% yield.
Functionalisation of [9]aneNS2 was achieved via reaction of
[9]aneNS2 in EtOH with 3 equivalents of isobutylene oxide
sealed in a sample vial for 10 days. Removal of the solvent led
to the isolation of the pendant-arm alcohol derivative HL1 in
quantitative yield (Scheme 2).
Cu–S1
Cu–S4
Cu–N7
S1–C2
S1–C9
C2–C3
2.5469(14)
2.5386(13)
2.016(4)
1.814(5)
1.816(6)
1.502(8)
C3–S4
S4–C5
C5–C6
C6–N7
N7–C8
C8–C9
1.812(5)
1.819(6)
1.512(7)
1.494(7)
1.496(7)
1.496(9)
S1–Cu–S4
S1–Cu–N7
S4–Cu–N7
C2–S1–C9
C3–C2–S1
C2–C3–S4
84.41(4)
85.79(13)
83.74(13)
102.7(3)
115.0(4)
118.1(4)
C3–S4–C5
C6–C5–S4
N7–C6–C5
C6–N7–C8
C9–C8–N7
C8–C9–S1
103.4(3)
112.0(4)
114.0(4)
111.7(4)
114.0(4)
114.4(4)
O
R
R
R
H
N
S
N
R
S
S
OH
S
EtOH
HL1: R = Me
HL2: R = Ph
Scheme 2
The potential co-ordination properties of functionalised
pendant-arm macrocycles can be altered by changing the steric
bulk of the substituents on the pendant arm. Peacock and co-
workers have reported10 that by changing the substituent on the
pendant-arm from methyl to isopropyl, a marked difference in
complex formation can be observed. In general, mononuclear
complexes of divalent metal ions incorporating pendant-
alcohol donors are often found to be protonated, the retention
of the alcohol proton in divalent metal–ion complexes being
attributed to the poorer Lewis acidity of M() ions in com-
parison with M() ions. Also, the higher the oxidation state of
the metal centre co-ordinated to an alcohol, the more acidic
is the alcohol proton.10 Interestingly, mononuclear M() com-
plexes with alkoxide ligands can be prepared if electron-
withdrawing groups are present, thereby increasing the acidity
of the alcohol proton. An example of such a complex is Na2-
Cu[OCH(CF3)2]4.11
We were interested in the preparation of pendant-arm
derivatives of [9]aneNS2 containing bulky substituents on the
pendant-arm in order to compare the co-ordination behaviour
with that of HL1. The macrocycle HL2 was prepared from
the reaction between [9]aneNS2 and 2,2-diphenyloxirane. The
oxirane was prepared according to the method reported by
Corey,12 and reaction of 2,2-diphenyloxirane with [9]aneNS2 in
refluxing EtOH for 2 days, followed by flash column chrom-
atography on alumina affords HL2 in 52% yield.
Fig. 1 View of structure of [Cu([9]aneNS2)2][PF6]2 with numbering
scheme adopted.
manifests itself in the Cu–N distances, with relatively elongated
Cu–S distances. The structure of [Cu([9]aneNS2)2]2ϩ is therefore
similar to [Cu([18]aneN2S4)]2ϩ, Cu–N 2.007(13), 2.036(12),
Cu–S 2.577(5), 2.487(5), 2.528(5), 2.578(5) Å,13 the larger ligand
offering the same co-ordination donor set and geometry to the
metal centre as two [9]aneNS2 ligands. The average Cu–S and
Cu–N bond distances of [Cu([9]aneNS2)2]2ϩ and [Cu([18]ane-
N2S4)]2ϩ are very similar, indicating that the metal centre is
dominating the co-ordination environment in both cases. The
X-band EPR spectrum of [Cu([9]aneNS2)2][PF6]2 recorded as a
frozen glass at 77 K in MeCN shows a strong broad spectrum
with g1 = 2.122, g2 = 2.056, g3 = 2.009.
Complexation studies
[Cu([9]aneNS2)2][PF6]2. Addition of Cu(NO3)2ؒ3H2O in
EtOH to [9]aneNS2 in EtOH immediately affords a deep green
solution. Counter-anion exchange can be achieved by the add-
ition of excess NH4PF6 in H2O to give the complex [Cu([9]ane-
NS2)2][PF6]2 as a deep green solid. The stoichiometry of the
complex was confirmed by mass spectrometry and elemental
analysis. Slow diffusion of Et2O into a solution of the complex
in MeCN led to the isolation of green columnar crystals
suitable for X-ray analysis. The crystal structure of [Cu([9]ane-
NS2)2][PF6]2 confirms (Fig. 1, Table 1) facial co-ordination of
the two tridentate ligands to Cu(). The Cu() centre, which
occupies a crystallographic inversion centre, is co-ordinated by
one N- and two S-donors from each ligand to give an overall
distorted octahedral geometry. Two geometrical isomers
are possible for [Cu([9]aneNS2)2]2ϩ, with the N-donors of the
rings positioned either mutually syn or anti to one another. In
this case the anti isomer is observed with four S-atoms bound
equatorially and two N-atoms occupying the axial positions,
Cu–S 2.5469(14), 2.5386(13), Cu–N 2.016(4) Å. Interestingly,
in the case of [Cu([9]aneN2S)2]2ϩ, Cu–N 2.09(1), 2.01(1),
Cu–S 2.707(1) Å,5 the Jahn–Teller distortion manifests itself
by elongation of the two axial S-atoms, which are anti to
one another. In [Cu([9]aneNS2)2]2ϩ the Jahn–Teller distortion
There are few sandwich complexes of type [M([9]aneNS2)2]nϩ
reported in the literature. The structure of [Ni([9]aneNS2)2]2ϩ
shows8 octahedral co-ordination at the metal centre with the
two nitrogen atoms anti to one another and the four S-donors
and the Ni() centre lying in the equatorial plane, Ni–N
2.104(4), Ni–S 2.408(1), 2.415(1) Å. The structure of [Zn-
([9]aneNS2)2]2ϩ, Zn–N 2.121(4), Zn–S 2.540(1), 2.546(1) Å,
shows14 a similar structural motif to [Cu([9]aneNS2)2]2ϩ and
[Ni([9]aneNS2)2]2ϩ. In [Pd([9]aneNS2)2]2ϩ 15
the Pd() centre is
,
co-ordinated to two N- and two S-donors in a square-planar
configuration with Pd–N 2.081(9), Pd–S 2.322(3) Å. Two long-
range apical interactions are provided by the two remaining
sulfur atoms at 3.011(3) Å.
[Cu([9]aneNS2)2]2ϩ exhibits an irreversible CuII/I reduction at
Epc = Ϫ0.92 V vs. Fc/Fcϩ. Significantly, this is 600 mV more
cathodic than the reversible couple observed for [Cu([18]-
aneN2S4)]2ϩ 13
,
indicating that the larger [18]aneN2S4 is able
to stabilise the Cu() oxidation state more effectively than
3970
J. Chem. Soc., Dalton Trans., 1998, 3969–3976

View Article Online
Table 2 Selected bond lengths (Å) and angles (Њ) for [Cu(L1)]2[BPh4]2
Cu–N1
Cu–S4
Cu–S7
Cu–O14
Cu–CuЈ
Cu–O14Ј
N1–C2
N1–C9
N1–C10
C2–C3
2.042(4)
2.452(2)
2.430(2)
1.927(4)
3.0063(9)
1.922(4)
1.482(7)
1.499(7)
1.499(7)
1.512(8)
C3–S4
S4–C5
C5–C6
C6–S7
S7–C8
C8–C9
C10–C11
C11–C12
C11–C13
C11–O14
1.812(6)
1.804(6)
1.515(8)
1.823(6)
1.818(6)
1.501(8)
1.536(8)
1.521(8)
1.523(8)
1.420(6)
N1–Cu–S4
N1–Cu–S7
N1–Cu–O14
S4–Cu–S7
86.53(12)
89.00(12)
85.6(2)
C3–S4–C5
S4–C5–C6
C5–C6–S7
Cu–S7–C6
Cu–S7–C8
C6–S7–C8
S7–C8–C9
N1–C9–C8
N1–C10–C11
C10–C11–C12
C10–C11–C13
C10–C11–O14
C12–C11–C13
C12–C11–O14
C13–C11–O14
Cu–O14–C11
Cu–O14–CuЈ
101.6(3)
118.1(4)
115.9(4)
102.4(2)
88.6(2)
103.00(3)
114.2(4)
113.1(5)
113.8(4)
114.7(5)
107.1(5)
105.0(4)
109.1(5)
110.8(4)
110.0(4)
116.7(3)
102.7(2)
88.39(5)
135.89(12)
134.67(12)
77.28(15)
109.6(3)
112.9(3)
104.6(3)
109(4(4)
111.9(4)
108.4(4)
113.6(5)
112.6(4)
95.1(2)
S4–Cu–O14
S7–Cu–O14
O14–Cu–O14Ј
Cu–N1–C2
Cu–N1–C9
Cu–N1–C10
C2–N1–C9
C2–N1–C10
C9–N1–C10
N1–C2–C3
C2–C3–S4
Cu–S4–C3
Cu–S4–C5
Fig. 2 View of structure of [Cu(L1)]2[BPh4]2 with numbering scheme
adopted.
[9]aneNS2. The irreversibility of the CuII/I couple in [Cu([9]ane-
NS2)2]2ϩ probably reflects the breaking up of the bis-sandwich
structure leading to the formation of Cu() oligomers.16 In gen-
eral, changing the donor atoms from nitrogen to sulfur has a
dramatic effect upon the electrochemistry of Cu() complexes.
For example, [Cu([9]aneN3)2]2ϩ has an irreversible reduction at
a potential of Ϫ1.41 V vs. Fc/Fcϩ.17 On replacing the N-donors
with S-donors the potential at which the CuII/I reduction occurs
becomes more anodic, Ϫ0.92 V vs. Fc/Fcϩ for [Cu([9]ane-
NS2)2]2ϩ and ϩ0.12 V vs. Fc/Fcϩ for [Cu([9]aneS3)2]2ϩ 18 reflect-
ing the ability of thioether S-donors to stabilise low oxidation
states.
101.1(2)
[Cu(L1)]2[BPh4]2. Reaction of Cu(CH3CO2)2 with 1 equiv-
alent of HL1 affords, after counter-anion metathesis and
recrystallisation from MeCN, a green product, analysis of
which indicates the empirical formula [Cu(L1)]BPh4. The pres-
ence of only one counter anion per Cu() centre suggested that
the ligand was deprotonated to form an alkoxide linkage. The
deprotonation of an alcohol to form an alkoxide on complex-
ation is unusual for a single 2ϩ cation, a 3ϩ charge being usu-
ally required to render the alcohol proton suitably acidic.1,10,19
We therefore argued that a binuclear structure for this complex
was likely. In principle a tetrameric cubane structure in which
the alkoxide donor bridges between three Cu() centres was
also possible, as reported for [{CuBr(OCH2CH2NEt2)}4]ؒ
Fig. 3 Magnetic susceptibility of [Cu(L1)]2[BPh4]2 per mol of Cu()
(᭺), emphasising the higher temperature measurements which reveal
a characteristic cusp for an antiferromagnetically-coupled binuclear
complex. The line through the data represents the best fit to a Bleaney–
Bowers equation plus a paramagnetic term and a temperature inde-
pendent term. The effective moment of the sample, once correction has
been made for the temperature independent term (᭹).
20
4CCl4 and for related phenoxy-bridged Schiff-base Cu()
Magnetic measurements were carried out on [Cu(L1)]2[BPh4]2
in the temperature range 4 to 300 K on a SQUID magneto-
meter (Quantum Design MPMS2) in a field of 0.1 T, and cor-
rected for the diamagnetism of the sample and holder (Fig. 3).
It is apparent from this figure that two magnetic species are
present: a cusp in the susceptibility centred in the region of
270 K may be fitted to the Bleaney–Bowers equation,26 with an
exchange coupling 2J of Ϫ407 2 cmϪ1; the rise in susceptibil-
ity on further cooling indicates that the material is contamin-
ated by a significant proportion of paramagnetic impurity, pos-
sibly arising from the presence of monomeric species in the
sample. All attempts to purify the compound by recrystallis-
ation and Sephadex column chromotography failed to remove
this impurity. This may suggest that a dynamic equilibrium
between monomeric and dimeric species is occurring in
solution.
complexes.21
Slow evaporation of a solution of the complex in MeCN
yielded green crystals suitable for X-ray structure determin-
ation. The structure shows (Fig. 2, Table 2) that the complex is
indeed dimeric with the formula [Cu(L1)]2[BPh4]2. Each Cu()
cation is five-co-ordinate being bound facially by the macro-
cycle, Cu–N 2.042(4), Cu–S 2.452(2), 2.430(2) Å. The alcohol
group is deprotonated and two [Cu(L1)]ϩ fragments are linked
by two alkoxide bridges, Cu–O 1.927(4), 1.922(4) Å, typical
for bridging alkoxide linkages to Cu().22–24 The overall co-
ordination geometry at the metal is distorted trigonal bipyr-
amidal, with S(4), S(7) and O(14) lying in the equatorial plane
and N(1) and O(14Ј) occupying the axial positions.
Two Cu() centres bridged by alkoxide ligands can show
interesting magnetic properties.24,25 Exchange processes can
occur between the metal centres and the unpaired electrons can
couple either antiferromagnetically or ferromagnetically. Anti-
ferromagnetic coupling leads to the observation of lower than
the predicted spin-only magnetic moment of 1.72 µB per metal
centre. Conversely, ferromagnetic coupling leads to a value
greater than that predicted.
The form of the data, and the chemical character of the sys-
tem indicate that the following expression (1) might represent
C
CЈ 2e2x
T 1 ϩ 3e2x
χmol = a ϩ b ͩ ͪϩ χTIP
(1)
T
J. Chem. Soc., Dalton Trans., 1998, 3969–3976
3971

View Article Online
Table 3 Selected bond lengths (Å) and angles (Њ) for [Ni(HL1)-
(CH3CO2)]BPh4ؒCH3CN
the susceptibility per mole of Cu() in the sample over the full
experimental range of temperature, where a and b are the mole
fractions of Cu() in the mononuclear and binuclear species
respectively; the second term is the Curie Law for S = ¹ with
Ni–N1
Ni–S4
Ni–S7
2.064(3)
2.3658(12)
2.3875(13)
2.061(3)
2.098(3)
2.102(3)
1.499(5)
1.493(5)
1.499(5)
1.528(6)
1.820(4)
1.826(4)
C5–C6
C6–S7
S7–C8
C8–C9
C10–C11
C11–C12
C11–C13
C11–O14
C15–O16
C15–O17
C15–C18
1.511(6)
1.822(4)
1.837(4)
1.523(6)
1.538(6)
1.532(7)
1.526(7)
1.452(5)
1.259(5)
1.290(5)
1.500(7)
¯
²
2
C = N(gmonomer2)µB /4k (where N is the Avogadro constant,
gmonomer is the Landé g factor for Cu() in the mononuclear
species, µB is the Bohr magneton and k the Boltzmann con-
stant); the third term is the Bleaney–Bowers equation where
Ni–O14
Ni–O16
Ni–O17
N1–C2
N1–C9
N1–C10
C2–C3
C3–S4
S4–C5
2
CЈ = N(gbinuclear2)µB /2k (where gbinuclear is the Landé g factor for
Cu() in the binuclear complex), x = J/kT; and χTIP is the tem-
perature independent susceptibility of Cu() (assumed to be the
same in the two species). Expression (1) was fitted successfully
to the data with all the parameters allowed to vary independ-
ently, yielding the optimised values a = 0.10 1, b = 0.83 5,
χTIP = 141 8 × 10Ϫ6 emu molϪ1 and 2J = 417 2 cmϪ1. The
oberved value of the magnetic moment of 1.68 µB per Cu()
at 300 K is unusually low for Cu(), typical values lying in
the range 1.9–2.3 µB, somewhat greater than the spin-only
N1–Ni–S4
N1–Ni–S7
N1–Ni–O14
N1–Ni–C15
N1–Ni–O16
N1–Ni–O17
S4–Ni–S7
89.16(10)
88.86(10)
79.06(12)
129.74(14)
99.43(12)
160.01(12)
89.20(4)
C2–C3–S4
Ni–S4–C3
Ni–S4–C5
C3–S4–C5
S4–C5–C6
Ni–S7–C6
C5–C6–S7
Ni–S7–C8
113.9(3)
92.57(14)
102.65(14)
101.0(2)
113.00(3)
100.8(2)
115.3(3)
95.23(14)
101.9(2)
111.2(3)
113.8(3)
114.0(4)
108.8(4)
113.3(4)
106.3(3)
110.0(4)
108.5(4)
109.8(4)
116.0(2)
177.90(3)
118.5(4)
121.4(4)
120.1(4)
89.8(3)
27
value of 1.732 µB on account of spin–orbit coupling with
excited orbital triplet states. χTIP is also anomalously high for
Cu(), and is more commonly about half this value. However,
it should be noted that the data taken at higher temperatures
correspond to a relatively weak signal for a dimer of small
spins with strong antiferromagnetic coupling, and correction
for the diamagnetism of the sample and container, combined
with correlation between values in the fit, can lead to signifi-
cant errors in fitted parameters. Thus, the value of 1.68 µB is
smaller than that expected for a mononuclear centre but is
consistent with the observed anti-ferromagnetic coupling for
the complex.
Magnetic data measured using a Faraday balance afforded
a value of 2J = Ϫ440 cmϪ1, in close accord with data obtained
from the SQUID magnetometer. The X-band EPR spectrum of
[Cu(L1)]2[BPh4]2 recorded as a frozen glass at 77 K in MeCN
shows a very weak signal at g|| = 2.434 and g⊥ = 2.082, with a
much stronger signal based at g = 2.01 for the mononuclear
impurity.
S4–Ni–O14
S4–Ni–C15
S4–Ni–O16
S4–Ni–O17
S7–Ni–O14
S7–Ni–C15
S7–Ni–O16
S7–Ni–O17
O14–Ni–C15
O14–Ni–O16
O14–Ni–O17
O16–Ni–O17
Ni–N1–C2
Ni–N1–C9
Ni–N1–C10
C2–N1–C9
C2–N1–C10
C9–N1–C10
N1–C2–C3
90.13(8)
140.62(11)
171.39(9)
108.77(8)
167.91(9)
96.48(11)
90.34(9)
C6–S7–C8
S7–C8–C9
N1–C9–C8
N1–C10–C11
C10–C11–C12
C10–C11–C13
C10–C11–O14
C12–C11–C13
C12–C11–O14
C13–C11–O14
Ni–O14–C11
Ni–C15–C18
O16–C15–O17
O16–C15–C18
O17–C15–C18
Ni–O16–C15
Ni–O17–C15
99.86(8)
91.69(13)
92.11(11)
91.79(11)
62.86(11)
113.4(2)
106.9(2)
103.8(2)
110.80(3)
113.5(3)
108.0(3)
88.8(2)
114.4(3)
The size and sign of 2J has been demonstrated to be directly
dependent upon the Cu–O–Cu angle (φ) for hydroxy-bridged
dimers, assuming planarity of the Cu2O2 fragment.24 An angle
below 97.6Њ results in ferromagnetic coupling and a positive
value for 2J, while for Cu–O–Cu angles above 97.6Њ anti-
ferromagnetic coupling is observed. At angles approaching
97.6Њ there is little or no exchange between the Cu() centres.
Binuclear Cu() centres with alkoxide bridges also exhibit a
dependence of 2J upon φ but there appears to be no such clear
linear relationship.25 More recently, Thompson and co-workers
have shown that the crossover between ferromagnetic and anti-
ferromagentic exchange in phenoxy-bridged binuclear Cu()
centres is significantly less than 90Њ.28 Significantly, the value of
φ in [Cu(L1)]2[BPh4]2 is 102.7(2)Њ consistent with the observed
antiferromagnetic coupling.
dence suggests an overall structure [Cu(L2)]2[BPh4]2. Unfortu-
nately, attempts to characterise this material by single crystal
X-ray studies were unsuccessful.
[Ni(HL1)(CH3CO2)]BPh4ؒCH3CN. Reaction of Ni(CH3-
CO2)2 with 1 equivalent of HL1 gives, after counter-anion
exchange with NaBPh4 and recrystallisation from MeCN, a
blue product. Infrared spectroscopy indicates the presence of
macrocycle, co-ordinated acetate and BPh4Ϫ counter anion. The
positions of the acetate stretching vibrations (1546 and 1410
cmϪ1) suggested that it was acting as a bidentate ligand.29 The
bands do not however determine whether the ligating mode of
the acetate is bidentate bridging or bidentate chelating. A struc-
tural determination was therefore undertaken to establish the
mode of acetate binding. Slow evaporation of a solution of the
complex in MeCN led to the isolation of crystals suitable for
X-ray analysis. The crystal structure confirms (Fig. 4, Table 3)
a Ni() centre co-ordinated by the macrocycle in the expected
facial manner, Ni–N(1) 2.064(3), Ni–S(4) 2.3658(12), Ni–S(7)
2.3875(13) Å. The pendant-arm alcohol is not deprotonated
and co-ordinates to the metal centre at a distance of 2.061(3) Å.
The co-ordination sphere is completed by a chelating bidentate
acetate ligand. The Ni() centre is in a very distorted octahedral
geometry, much of the distortion being due to the small bite
angle of the acetate of only 62.86(11)Њ.
The cyclic voltammogram of [Cu(L1)]2[BPh4]2 shows irrevers-
ible reductive behaviour with two irreversible reduction waves
at Epc = Ϫ0.3 and Ϫ1.0 V vs. Fc/Fcϩ. There is also an additional
oxidation observed at Epa = Ϫ0.2 V vs. Fc/Fcϩ. This oxidation
wave does not appear when the cyclic voltammetry experiment
is carried out between the potentials 0.0 and Ϫ0.25 V, suggest-
ing that this oxidation wave results from the daughter product
of reduction of the Cu() dimer.
[Cu(L2)]2[BPh4]2. Reaction of Cu(CH3CO2)2ؒH2O with 1
molar equivalent of HL2 in EtOH gives a dark green solution.
Addition of excess NaBPh4 afforded a grey–green solid, which
was recrystallised from MeCN yielding dark green columnar
crystals. The IR spectrum of this material and the analytical
data suggest an overall stoichiometry [Cu(L2)]BPh4. The FAB
mass spectrum of the product showed peaks for [HL2]ϩ and
[Cu(L2)]ϩ at m/z 360 and 422 respectively. The colour of this
material was identical to that of [Cu(L1)]2[BPh4]2, and the evi-
Current work is aimed at the investigation of the co-
ordination chemistry of these and related potential binucleating
ligands as a function of steric bulk and of electronic properties
of the pendant-arm system, and the study of the magneto-
chemical and redox properties of the resultant mono- and poly-
nuclear complexes.
3972
J. Chem. Soc., Dalton Trans., 1998, 3969–3976

View Article Online
48.22 (CH2N), 68.09 (CH2O), 126.99, 127.72, 129.76, 129.82
(aromatic CH), 132.09, 134.95, 143.96 and 145.03 (aromatic
quaternary).
7-(p-Tolylsulfonyl)-7-aza-1,4-dithiacyclononane.
A 5 litre
three necked round bottom flask equipped with a mechanical
stirrer, a precision dropping funnel and a reflux condenser was
purged with nitrogen. Freshly distilled DMF (2.2 litres) and dry
caesium carbonate (13.04 g, 0.04 mol) were added and the
mixture heated to 60 ЊC. A solution comprising ethane-1,2-
dithiol (1.88 g, 0.02 mol) and N,N-bis[2-(p-tolylsulfonyloxy)-
ethyl]toluene-p-sulfonamide (11.35 g, 0.02 mol) in DMF (300
cm3) was added via the dropping funnel over a period of 12
hours. After the addition was complete a second portion of
caesium carbonate (13.04 g, 0.04 mol) was added to the flask
followed by a further addition of ethane-1,2-dithiol (1.88 g,
0.02 mol) and N,N-bis[2-(p-tolylsulfonyloxy)ethyl]toluene-p-
sulfonamide (11.35 g, 0.02 mol) in DMF (300 cm3) over 12
hours. After the reactants had been added the yellow solution
was heated at 60 ЊC for a further 6 hours. The DMF was
removed in vacuo to yield a brown paste which was redissolved
in CH2Cl2 and washed with a copious amount of water. The
solvent was again removed and the residue redissolved in the
minimum amount of CH2Cl2–MeOH and eluted through a pad
of flash silica to remove the majority of the polymeric impur-
ities. The solvent was removed to reveal an off-white sticky
solid, which on repeated recrystallisation from hot ethanol gave
the pure tosylated macrocycle as white crystals 4.1 g, 32%.
δH(CDCl3) 2.43 (3H, s, CH3), 3.11 (4H, t, NCH2CH2S), 3.15
(4H, s, SCH2CH2S), 3.40 (4H, t NCH2CH2S) and 7.31–7.70
(8H, m, aromatic H).
Fig. 4 View of structure of the cation [Ni(HL1)(CH3CO2)]BPh4ؒ
CH3CN with numbering scheme adopted.
Experimental
Unless otherwise stated, commercial grade chemicals were used
without further purification. Isobutylene oxide was purchased
from the Lancaster Chemical Company.
7-Aza-1,4-dithiacyclononane ([9]aneNS2). 7-(p-Tolylsulfon-
yl)-7-aza-1,4-dithiacyclononane (1.75 g, 5.5 mmol) was added
to a solution of hydrogen bromide in acetic acid (45%, 30 cm3)
(Fluka) and phenol (3 g, 0.043 mol). The solution was stirred
at 80 ЊC for 48 hours, after which a further quantity of
hydrogen bromide in acetic acid (45%, 10 cm3) was added and
the reaction mixture was stirred for a further 30 hours at 80 ЊC.
The resulting black solution was allowed to cool and toluene
(100 cm3) added and the solvent removed in vacuo. The black
residue was taken up in water (40 cm3) and was washed with
CH2Cl2 until the organic layer became colourless. The pH of
the solution was adjusted to 14 with NaOH solution and the
aqueous layer was extracted with CHCl3 (5 × 50 cm3). The
combined organic layer was dried over MgSO4 and reduced in
vacuo to yield the product as a white crystalline solid. Further
purification was deemed unnecessary, 700 mg, 78%. δH(CDCl3)
2.76 (4H, m, NCH2CH2S), 2.88 (1H, br s, NH) and 2.94 (8H,
m, NCH2CH2S and SCH2CH2S); δC(CDCl3) 39.06 (NCH2CH2S
and SCH2CH2S) and 47.96 (NCH2CH2S); m/z 163 [Mϩ].
Instrumental methods
Elemental analyses were carried out by the University of
Nottingham Analytical Service within the School of Chemistry.
Infrared spectra were recorded on a Perkin-Elmer 1600 series
FT-IR spectrometer. NMR spectra (1H and 13C) were recorded
on a Bruker DPX300 instrument operating at 300 and 75.15
MHz respectively. Cyclic voltammetry was carried out with an
Autolab PGStat20 potentiostat using a Ag–AgCl reference
electrode and Bu4NPF6 as base electrolyte. UV/VIS spectra
were recorded on a Unicam UV/VIS 2 spectrophotometer. Fast
atom bombardment (FAB) and electron impact mass spectra
were run on a Kratos MS50TC spectrometer. X-Band EPR
spectra were recorded on a Bruker EMX EPR spectrometer
employing 100 kHz modulation. Spectra were recorded as
frozen glasses at 77 K under a nitrogen atmosphere. Magnetic
measurements were carried out on a MPMS2 SQUID magnet-
ometer (Quantum Design), at the University of Edinburgh,
operating with a magnetic field of 1000 G. Diamagnetic correc-
tions were calculated using Pascal’s constants. Single X-ray
data were collected on a Stoë STADI-4 four-circle diffract-
ometer, fitted with an Oxford Cryosystems low temperature
device.30
7-(2-Hydroxy-2-methylpropyl)-7-aza-1,4-dithiacyclononane
(HL1). 7-Aza-1,4-dithiacyclononane (0.4 g, 25 mmol) and iso-
butylene oxide (0.53 g, 74 mmol) were dissolved in ethanol (15
cm3) and left in a sealed flask for 10 days. The solvent and excess
isobutylene oxide were removed in vacuo to yield the ligand as
a pale yellow oil, 0.575 g, quantitative. δH(CDCl3) 1.08 (6H, s,
CH3), 2.62–2.94 (8H, m, NCH2CH2S), 2.89 (4H, s, SCH2CH2S)
and 3.58 (1H, br s, OH); δC(CDCl3) 28.08 (CH3), 34.09, 34.89
(NCH2CH2S and SCH2CH2S), 58.68 (NCH2CH2S), 69.27
(NCH2C(CH3)2OH) and 69.27 (NCH2C(CH3)2OH).
Syntheses
N,N-Bis[2-(p-tolylsulfonyloxy)ethyl]toluene-p-sulfonamide.
Diethanolamine (19.01 g, 0.181 mol) was dissolved in dry
triethylamine (300 cm3). The solution was cooled to 0 ЊC and
p-toluenesulfonyl chloride (103.2 g, 0.543 mol) was added in
small portions so as to keep the temperature below 5 ЊC. After
the final addition the solution was stirred for 1 hour and the
resulting white precipitate was filtered off and washed with
copious amounts of water. The dried solid was recrystallised
from chloroform–diethyl ether to give the product as a white
solid, 82.8 g, 80.7%. δH(CDCl3) 2.45 (3H, s, CH3), 2.48 (3H,
s, CH3), 4.00 (4H, t, CH2N), 4.13 (4H, t, CH2O) and 7.30–
8.0 (12H, s, aromatic H); δC(CDCl3) 21.32, 21.46 (CH3),
7-[2-Hydroxy-2,2-diphenyl)ethyl]-7-aza-1,4-dithiacyclo-
nonane (HL2). (a) 2,2-Diphenyloxirane. This compound was
prepared according to the method of Corey and Chaykovsky.12
Sodium hydride (2.4 g of 60% dispersion in mineral oil, 0.06
mol) was weighed into a dry Schlenk tube. This was then
washed carefully three times with light petroleum (bp 40–
60 ЊC), and the sample pumped dry on a schlenk line. Trimethyl
J. Chem. Soc., Dalton Trans., 1998, 3969–3976
3973

View Article Online
Table 4 Crystallographic dataa
[Cu([9]aneNS2)2][PF6]2
[Cu(L1)]2[BPh4]2
[Ni(HL1)(CH3CO2)]BPh4ؒCH3CN
Chemical formula
M
C12H26F12N2P2S4Cu
680.07
C68H80B2N2O2S4Cu2
1234.34
C36H44BNO3S2NiؒCH3CN
713.4
Crystal system
a/Å
b/Å
c/Å
α/Њ
Monoclinic
7.5184(11)
9.1630(14)
16.925(3)
Triclinic
9.723(2)
10.628(2)
15.165(4)
95.77(2)
Monoclinic
16.921(13)
12.139(9)
19.319(11)
β/Њ
94.298(13)
92.120(2)
104.498(13)
1506
113.66(5)
γ/Њ
U/Å3
1162.7
298
P21/c
2
1.538
2036
3634.6
150b
P21/n
4
0.682
5123
T/K
298
¯
Space group
Z
P1
1
µ/mmϪ1
0.886
3775
Reflections collected
Observed reflections [F у 4σ(F)]
1595
147
—
2759
313
0.0431, 0.0444
—
4098
386
0.0482, 0.0482
—
Parameters refined
R, RЈ31
R1, wR232
0.0481, 0.1199
a Stoë STADI-4 four-circle diffractometer, graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å). b Oxford Cryosystems low-temperature
device.30
sulfoxonium iodide [Me3S(O)I] (13.2 g, 0.06 mol) in DMSO (60
cm3) was added and the reaction mixture stirred at room tem-
perature until the effervescence had ceased (20 min) to generate
dimethylsulfoxonium methylide. A solution of benzophenone
(8.90 g, 0.050 mol) in DMSO (20 cm3) was then added and the
solution stirred at 50 ЊC for 1 hour. The flask was allowed to
cool, water (120 cm3) was added and the mixture was extracted
with ether (4 × 50 cm3). The combined extracts were washed
with water (2 × 20 cm3), dried over MgSO4 and concentrated in
vacuo to yield a white paste. Recrystallisation of this paste from
ethanol yielded the product as a white solid which was stored at
Ϫ20 ЊC (6.10 g, 51.8%). Rf = 0.9 (1:1 CH2Cl2–hexane on alu-
mina); 1H NMR (250.13 MHz, CDCl3) δ 3.35 (2H, s, CH2) and
7.43 (10H, m, aromatic H); 13C NMR (62.90 MHz, CDCl3) δ
56.57 (CH2), 61.54 [C(Ph)2], 127.24, 127.70, 128.04 (aromatic
CH) and 139.35 (aromatic quaternary); IR (KBr disc) 3053m
(CH), 2986m (CH), 1491s, 1446s, 1345s, 1302s, 900s, 757s and
N, 4.1 %); m/z 389 (M Ϫ 2PF6). Electronic spectrum: λmax/nm
(MeCN) 582 (ε/dm3 molϪ1 cmϪ1 363).
[Cu(L1)]2[BPh4]2. Cu(CH3CO2)2ؒH2O (42 mg, 0.21 mmol) in
MeOH (20 cm3) was added to a solution of HL1 (49 mg, 0.21
mmol) in MeOH (20 cm3). The resulting green solution was
added to a solution of NaBPh4 (0.145 g, 0.42 mmol) in meth-
anol (10 cm3) and the fine precipitate was isolated by centri-
fugation and recrystallised from MeCN to yield the complex as
green crystals, 81 mg, 62% (Found: C, 67.0; H, 6.9; N, 2.2.
C68
H80N2O2S4Cu2B2 requires C, 66.2; H, 6.5; N, 2.3%). Elec-
tronic spectrum: λmax/nm (MeCN) 618 (ε/dm3 molϪ1 cmϪ1 555).
[Cu(L2)]2[BPh4]2. Cu(CH3CO2)2ؒH2O (0.028 g, 0.00014 mol)
and HL2 (0.050 g, 0.00014 mol) were each dissolved in MeOH
(20 cm3). Mixing of the two solutions gave a colour change to
dark green. NaBPh4 (0.096 g, 0.00028 mol) was added as a
solution in MeOH (10 cm3) to yield a fine grey–green precipi-
tate. This was isolated by centrifugation and recrystallised from
a large volume of warm MeCN, to afford the product as dark
green columns (0.044 g, 42.0%) (Found: C, 71.0; H, 6.14; N,
1.82. C88H88N2O2S4B2Cu2 requires C, 71.3; H, 5.94; N, 1.89%);
IR (KBr disc) 3053w, 2982m, 1551s and 1420m cmϪ1; FAB-MS
(3-nitrobenzyl alcohol): m/z 360 [HL2]ϩ, 422 [Cu(L2)]ϩ.
696s cmϪ1
.
(b) 7-[(2-Hydroxy-2,2-diphenyl)ethyl]-7-aza-1,4-dithiacyclo-
nonane (HL2). 7-Aza-1,4-dithiacyclononane (0.20 g, 0.0012
mol) and 2,2-diphenyloxirane (0.72 g, 0.0037 mol) were heated
at 60 ЊC in ethanol (10 cm3) for 24 hours. The reaction was
found to be incomplete by TLC. A second portion of oxirane
(0.20 g, 0.0010 mol) was added and the mixture heated for a
further 24 hours. The solvent was then removed in vacuo and
the product was isolated by flash column chromatography on
alumina (1:1 CH2Cl2–hexane). After removal of the solvent in
vacuo and trituration with ethanol, the product was obtained as
a white solid (0.230 g, 52.1%). Rf = 0.35 (1:1 CH2Cl2–hexane on
[Ni(HL1)(CH3CO2)]BPh4. This complex was prepared in a
similar manner to the Cu() complex of [9]aneNS2, 84 mg,
39% (Found: C, 64.6; H, 7.2; N, 3.7. C36H44NO3S2NiBؒCH3CN
requires C, 64.0; H, 6.6; N, 3.9%).
1
alumina); H NMR (250.13 MHz, CDCl3) δ 2.5–2.85 (8H, m,
NCH2CH2S), 2.83 (4H, s, SCH2CH2S), 3.48 (2H, s, NCH2 arm),
7.15–7.59 (10H, m, aromatic H); 13C NMR (62.90 MHz, CDCl3)
δ 33.99, 35.08 (SCH2), 58.13 (NCH2, ring), 68.95 (NCH2, arm),
75.88 [C(Ph)2OH], 125.54, 126.33, 127.81 (aromatic CH) and
146.62 (aromatic quaternary).
X-Ray crystallography
A summary of the crystal data, data collection and refinement
parameters for the three compounds [Cu([9]aneNS2)2][PF6]2,
[Cu(L1)]2[BPh4]2 and [Ni(HL1)(CH3CO2)]BPh4 is given in Table
4. The positions of the metal atom in all three structures were
deduced from Patterson syntheses and the remaining atoms
from subsequent difference-Fourier syntheses.
[Cu([9]aneNS2)2][PF6]2. 7-Aza-1,4-dithiacyclononane (0.1 g,
0.6 mmol) was dissolved in ethanol (3 cm3). To this was added
a solution of Cu(NO3)2ؒ3H2O (74 mg, 0.3 mmol) in ethanol
(3 cm3). A green precipitate immediately formed which was col-
lected by filtration. The complex was dissolved in a minimum
of water and was added to an excess of NH4PF6. The resulting
green precipitate was collected by filtration and recrystallised
from acetonitrile–diethyl ether, 110 mg, 53% (Found: C, 21.5;
H, 4.0; N, 4.1. C12H26N2S4CuP2F12 requires C, 21.2; H, 3.8;
[Cu([9]aneNS2)2][PF6]2. Initial refinement showed high ther-
mal parameters for four of the F atoms on the PF6 anion
Ϫ
indicating the presence of some rotational disorder: each was
resolved into two components with site occupancy factors of
0.5. All non-disordered H-atoms were refined with anisotropic
thermal parameters. Hydrogen atoms were included in fixed
calculated positions with Uiso(H) = 1.2 Ueq(C).
3974
J. Chem. Soc., Dalton Trans., 1998, 3969–3976

View Article Online
[Cu(L1)]2[BPh4]2. Phenyl rings in the anions were constrained
as rigid, idealised hexagons and hydrogen atoms were included
in calculated positions (C–H 1.08 Å) with fixed thermal param-
eters Uiso = 0.04 Å2. In the final cycles of full-matrix least-
squares refinement, all non H-atoms were refined with aniso-
tropic thermal parameters.
13 G. Reid and M. Schröder, Chem. Soc. Rev., 1990, 19, 239;
N. Atkinson, A. J. Blake, M. G. B. Drew, G. Forsyth, A. J. Lavery,
G. Reid and M. Schröder, J. Chem. Soc., Chem. Commun., 1989,
984; N. Atkinson, A. J. Blake, M. G. B. Drew, G. Forsyth, R. O.
Gould, A. J. Lavery, G. Reid and M. Schröder, J. Chem. Soc.,
Dalton Trans., 1992, 2993; J. L. Wang, Y. Zhou, X. S. Miao, F. M.
Miao and W. Z. Li, J. Struct. Chem. (Engl. Transl.), 1996, 15, 171.
14 A. J. Amoroso, A. J. Blake, J. P. Danks, W.-S. Li and M. Schröder,
unpublished work.
[Ni(HL1)(CH3CO2)]BPh4. In the final cycles of refinement,
all non H-atoms were refined with anisotropic thermal param-
eters and with the phenyl rings of the BPh4 anion constrained
to be rigid idealised hexagons. All H-atoms were placed at ideal-
ised positions (C–H 1.08 Å) with fixed thermal parameters
Uiso = 0.04 Å2, with the exception of the hydroxylic H(14) which
was located in a difference-Fourier synthesis and restrained to
lie 0.96(1) Å from O(14).
15 A. J. Blake, R. D. Crofts, B. DeGroot and M. Schröder, J. Chem.
Soc., Dalton Trans., 1993, 485.
16 J. A. Clarkson, R. Yagbasan, P. J. Blower and S. R. Cooper, J. Chem.
Soc., Chem. Commun., 1989, 1244; H.-J. Küppers, K. Wieghardt,
Y.-H. Tsay, C. Krüger, B. Nuber and J. Weiss, Angew. Chem., Int.
Ed. Engl., 1987, 26, 575; Sanaullah, H. Hungerbuhler, C. Schoneich,
M. Morton, D. G. Vander Velde, G. S. Wilson, K.-D. Asmus and
R. S. Glass, J. Am. Chem. Soc., 1997, 119, 2134.
17 A. D. Beveridge, A. J. Lavery, M. D. Walkinshaw and M. Schröder,
J. Chem. Soc., Dalton Trans., 1987, 373; P. Chaudhuri, K. Oder,
K. Wieghardt, J. Weiss, J. Reedijk, W. Hinrichs, J. Wood, A.
Ozarowski, H. Stratenmeier and D. Reinen, Inorg. Chem., 1986,
25, 2951.
CCDC reference number 186/1153.
Acknowledgements
18 J. R. Hartman and S. R. Cooper, J. Am. Chem. Soc., 1986, 108,
1202.
We thank the EPSRC for support, and the EPSRC Mass
Spectrometry National Service at the University of Swansea for
Mass Spectra. We also thank Dr C. Harding (Open University)
for magnetic measurements.
19 A. A. Belal, L. J. Farrugia, R. D. Peacock and J. J. Robb, J. Chem.
Soc., Dalton Trans., 1989, 931; A. A. Belal, P. Chaudhuri, I. A.
Fallis, L. J. Farrugia, R. Hartung, N. M. Macdonald, B. Nuber,
R. D. Peacock, J. Weiss and K. Wieghardt, Inorg. Chem., 1991, 30,
4397; I. A. Fallis, L. J. Farrugia, N. M. Macdonald and R. D.
Peacock, Inorg. Chem., 1993, 32, 779; H. Al-Sagher, I. A. Fallis,
L. J. Farrugia and R. D. Peacock, J. Chem. Soc., Chem. Commun.,
1993, 1499; A. J. Blake, I. A. Fallis, S. Parsons, S. A. Ross and
M. Schröder, J. Chem. Soc., Chem. Commun., 1994, 2467; A. J.
Blake, I. A. Fallis, A. Happeler, S. Parsons, S. A. Ross and
M. Schröder, J. Chem. Soc., Dalton Trans., 1996, 31; A. J. Blake,
I. A. Fallis, S. Parsons, S. A. Ross and M. Schröder, J. Chem. Soc.,
Dalton Trans., 1996, 525; A. J. Blake, T. M. Donlevy, P. A. England,
I. A. Fallis, S. Parsons, S. A. Ross and M. Schröder, J. Chem. Soc.,
Chem. Commun., 1994, 1981; A. J. Blake, I. A. Fallis, R. O. Gould,
S. Parsons, S. A. Ross and M. Schröder, J. Chem. Soc., Dalton
Trans., 1996, 4379 and refs. therein.
References
1 R. I. Haines and A. McAuley, Coord. Chem. Rev., 1981, 37, 77;
P. Chaudhuri and K. Wieghardt, Prog. Inorg. Chem., 1987, 25,
329.
2 A. J. Blake and M. Schröder, Adv. Inorg. Chem., 1990, 35, 1; S. R.
Cooper and S. C. Rawle, Struct. Bonding (Berlin), 1990, 72, 1.
3 J. P. Danks, N. R. Champness and M. Schröder, Coord. Chem.Rev.,
1998, 174, 417; A. J. Blake, J. P. Danks, A. Harrison, S. Parsons,
G. Whittaker and M. Schröder, J. Chem. Soc., Dalton. Trans., 1998,
2335.
4 L. R. Gahan, G. A. Lawrence and A. M. Sargeson, Aust. J. Chem.,
1982, 35, 1119; L. R. Gahan, T. W. Hambley and A. M. Sargeson,
Inorg. Chem., 1982, 21, 2699; S. M. Hart, J. C. A. Boeyens, J. P.
Michael and R. D. Hancock, J. Chem. Soc., Dalton Trans., 1983,
1601; P. Chaudhuri, K. Wieghardt, H. Tsay and C. Krüger, Inorg.
Chem., 1984, 23, 427; M. Hann and K. Wieghardt, Inorg. Chem.,
1984, 23, 2977; G. Backes-Dahmann and K. Wieghardt, Inorg.
Chem., 1985, 24, 4049; G. Backes-Dahmann, W. Hermann,
K. Wieghardt and J. Weiss, Inorg. Chem., 1985, 24, 485; R. D.
Hancock, S. M. Dobson and J. C. A. Boeyens, Inorg. Chim. Acta,
1987, 133, 221; D. G. Fortier and A. McAuley, Inorg. Chem., 1989,
28, 655; B. Chak, A. McAuley and T. W. Whitcombe, Can. J. Chem.,
1994, 72, 1525; L. R. Gahan, V. A. Grillo, T. W. Hambley, G. R.
Hanson, C. J. Hawkins, E. M. Proudfoot, B. Moubaraki, K. S.
Murray and D. Wang, Inorg. Chem., 1996, 35, 1044; V. A. Grillo,
G. R. Hanson, T. W. Hambley, L. R. Gahan, K. S. Murray and
B. Moubaraki, J. Chem. Soc., Dalton Trans., 1997, 305.
20 R. Mergehenn, L. Merz and W. Haase, J. Chem. Soc., Dalton
Trans., 1980, 1703.
21 A. J. Atkins, A. J. Blake, D. Black, A. Marin-Becerra, S. Parsons,
L. Ruiz-Ramirez and M. Schröder, Chem. Commun., 1996, 457.
22 T. Tokii, S. Nakahara, N. Hashimoto, M. Koikawa, M. Nakashima
and H. Matsushima, Bull. Chem. Soc. Jpn., 1995, 68, 2533; Y.
Brussaard, F. Olbrich and U. Behrens, J. Organomet. Chem., 1996,
519, 115; A. M. Garcia, J. Manzur, M. T. Garland, R. Baggio,
O. Gonzalez, O. Pena and E. Spodine, Inorg. Chim. Acta, 1996, 248,
247; G. De Munno, M. Julve, F. Lloret, J. Faus, M. Verdaguer and
A. Caneschi, Inorg. Chem., 1995, 34, 157; S. Itoh, S. Takayama,
R. Arakawa, A. Furuta, M. Komatsu, A. Ishida, S. Takamuku and
S. Fukuzumi, Inorg. Chem., 1997, 36, 1407; T. C. Higgs, M.
Helliwell, E. J. L. McInnes, F. E. Mabbs, C. J. Harding and C. D.
Garner, J. Chem. Soc., Dalton Trans., 1997, 927; V. Tangoulis, C. P.
Raptopoulou, S. Paschalidou, A. E. Tsohos, E. G. Bakalbassis,
A. Terzis and S. P. Perlepes, Inorg. Chem., 1997, 36, 5270; F. Zippel,
F. Ahlers, R. Werner, W. Haase, H.-F. Nolting and B. Krebs, Inorg.
Chem., 1996, 35, 3409; L. J. Farrugia, P. A. Lovatt and R. D.
Peacock, Inorg. Chim. Acta, 1996, 246, 343; H. L. Shyu, H. H. Wei,
G. H. Lee and Y. Wang, Inorg. Chem., 1996, 35, 5396; M. J.
MacLachlan, M. K. Park and L. K. Thompson, Inorg. Chem., 1996,
35, 5492; L. Chen, S. R. Breeze, R. J. Rousseau, S. Wang and L. K.
Thompson, Inorg. Chem., 1995, 34, 454; M. Lubben, R. Hage,
A. Meetsma, K. Byma and B. L. Feringa, Inorg. Chem., 1995, 34,
2217; A. J. Blake, C. M. Grant, S. Parsons and R. E. P. Winpenny,
J. Chem. Soc., Dalton Trans., 1995, 1765; S. Myllyviita, R. Sillanpaa,
J. J. A. Kolnaar and J. Reedijk, J. Chem. Soc., Dalton Trans., 1995,
2209; P. E. Kruger, G. D. Fallon, B. Moubaraki, K. J. Berry and
K. S. Murray, Inorg. Chem., 1995, 34, 4808; G. A. van Albada, M. T.
Lakin, N. Veldman, A. L. Spek and J. Reedijk, Inorg. Chem., 1995,
34, 4910; K. Motoda, H. Sakiyama, N. Matsumoto, H. Okawa and
D. E. Fenton, J. Chem. Soc., Dalton Trans., 1995, 3419; S. S.
Tandon, L. K. Thompson, J. N. Bridson and C. Benelli, Inorg.
Chem., 1995, 34, 5507; S. C. Chan, L. L. Koh, P.-H. Leung, J. D.
Ranford and K. Y. Sim, Inorg. Chim. Acta, 1995, 236, 101;
N. Marsich, A. Camus, F. Ugozzoli, A. M. M. Lanfredi, Inorg.
Chim. Acta, 1995, 236, 117; D. Ghosh, T. K. Lal, S. Ghosh and
R. Mukherjee, Chem. Commun., 1996, 13; M. M. Whittaker, W. R.
Duncan and J. W. Whittaker, Inorg. Chem., 1996, 35, 382; D.-H. Lee,
N. N. Murthy and K. D. Karlin, Inorg. Chem., 1996, 35, 804 and
5 J. C. A. Boeyens, S. M. Dobson and R. D. Hancock, Inorg. Chem.,
1985, 24, 3073; L. R. Gahan, C. H. L. Kennard, G. Smith and
T. C. W. Mak, Transition Met. Chem., 1986, 11, 465.
6 P. Hoffmann, A. Steinhoff and R. Mattes, Z. Naturforsch., Teil B,
1987, 42, 867; P. Hoffmann and R. Mattes, Z. Naturforsch., Teil B,
1988, 43, 261; P. Hoffmann, F.-J. Hermes and R. Mattes,
Z. Naturforsch., Teil B, 1988, 43, 567; K. Wasieliewski and
R. Mattes, Acta Crystallogr., Sect. C, 1990, 46, 1826; U. Heinzel
and R. Mattes, Polyhedron, 1991, 10, 19; P. Hoffmann and
R. Mattes, Inorg. Chem., 1989, 28, 2092; U. Heinzel and R. Mattes,
Inorg. Chim. Acta, 1992, 194, 157; K. Wasielewski and R. Mattes,
Z. Naturforsch., Teil B, 1992, 47, 1795; U. Heinzel and R. Mattes,
Polyhedron, 1992, 11, 597; K. Wasieliewski and R. Mattes, Z. Anorg.
Allg. Chem., 1993, 619, 158; U. Heinzel, A. Henke and R. Mattes,
J. Chem. Soc., Dalton Trans., 1997, 501.
7 A. S. Craig, R. Kataky, R. C. Matthews, D. Parker, G. Ferguson,
A. Lough, H. Adams, N. Bailey and H. Schneider, J. Chem. Soc.,
Perkin Trans. 2, 1990, 1523.
8 A. McAuley and S. Subramanian, Inorg. Chem., 1990, 29, 2830.
9 S. Chandrasekhar and A. McAuley, Inorg. Chem., 1992, 31, 2234.
10 I. A. Fallis, L. J. Farrugia, N. M. Macdonald and R. D. Peacock,
J. Chem. Soc., Dalton Trans., 1993, 2759.
11 A. P. Purdy, C. F. George and J. H. Callahan, Inorg. Chem., 1991, 30,
2812.
12 E. J. Corey and M. Chaykovsky, J. Am. Chem. Soc., 1965, 87, 1353.
J. Chem. Soc., Dalton Trans., 1998, 3969–3976
3975

View Article Online
S. R. Breeze, S. Wang and L. Chen, J. Chem. Soc., Dalton Trans.,
1996, 1341.
23 K. T. McGregor, N. T. Walkins, D. L. Lewis, D. J. Hodgson and
W. E. Hatfield, Inorg. Chem., 1974, 13, 756.
24 D. J. Hodgson, Prog. Inorg. Chem., 1975, 19, 173; Inorg. Chem.,
1976, 15, 2107.
25 Y. Shiping, C. Peng, P. Jiuhe, L. Daizheng, J. Zonghui and
W. Genglin, Polyhedron, 1994, 13, 1801; G. De Munno, D. Viterbo,
A. Caneschi, F. Lloret and M. Julve, Inorg. Chem., 1994, 33, 1585;
K. Osakada, T. Takizawa, M. Tanaka and T. Yamamoto,
J. Organomet. Chem., 1994, 473, 359; S. S. Tandon, L. K.
Thompson, J. N. Bridson and A. J. Downard, Inorg. Chem., 1992,
31, 4635; A. W. Addison, Inorg. Nucl. Chem. Lett., 1976, 12, 899;
R. R. Gagne, C. A. Koval, T. J. Smith and M. C. Cimolino, J. Am.
Chem. Soc., 1979, 101, 4571; S. K. Mandal and K. J. Nag, J. Chem.
Soc., Dalton Trans., 1983, 2429; R. S. Long and D. N. Hendrickson,
J. Am. Chem. Soc., 1983, 105, 1513; S. K. Mandal and K. J. Nag,
J. Chem. Soc., Dalton Trans., 1984, 2141; S. K. Mandal, L. K.
Thompson, K. J. Nag, J. P. Charland and E. J. Gabe, Can. J. Chem.,
1987, 65, 2815; P. Lacroix, O. Kahn, F. Theobald, J. Leroy and
C. Wakselman, Inorg. Chim. Acta, 1988, 142, 129.
28 L. K. Thompson, S. K. Manat, S. S. Tandon, J. N. Bridson and
M. K. Park, Inorg. Chem., 1996, 35, 3117; see also: P. J. Hay, J. C.
Thibeault and R. Hoffmann, J. Am. Chem. Soc., 1975, 97, 4884;
M. F. Charlot, S. Jeannin, Y. Jeannin, O. Kahn, J. Lucreace-Abaul
and J. Martin-Frere, Inorg. Chem., 1979, 18, 1675 and M. F. Charlot,
O. Kahn, S. Jeannin and Y. Jeannin, Inorg. Chem., 1980, 19, 1410;
E. V. Rybak-Akimova, D. H. Busch, P. K. Kahol, N. Pinto, N. W.
Alcock and H. J. Clase, Inorg. Chem., 1997, 36, 510.
29 C. Oldham, in Comprehensive Coordination Chemistry, ed. R. D.
Gillard and J. A. McCleverty, Pergamon Press, Oxford, 1987, vol. 2,
section 15.6; N. W. Alcock, V. M. Tracy and T. C. Waddington,
J. Chem. Soc., Dalton Trans., 1976, 22431; N. W. Alcock and V. M.
Tracy, Acta Crystallogr., Sect. B, 1979, 35, 80; P. J. Roberts,
G. Ferguson, R. J. Goel, W. O. Ogini and R. J. Restivo, J. Chem.
Soc., Dalton Trans., 1978, 253.
30 J. Cosier and A. M. Glazer, J. Appl. Crystallogr., 1986, 19, 105.
31 G. M. Sheldrick, SHELX 76, Program for crystal structure refine-
ment, University of Cambridge, 1976.
32 G. M. Sheldrick, SHELXL-96, University of Göttingen, 1996.
26 B. Bleaney and K. D. Bowers, Proc. R. Soc. London, A, 1952, 214,
451.
27 R. L. Carlin, Magnetochemistry, Springer, Berlin, 1986; F. A.
Cotton and G. Wilkinson, Advanced Inorganic Chemistry, Wiley,
New York, 4th edn., 1980.
Paper 8/04303E
3976
J. Chem. Soc., Dalton Trans., 1998, 3969–3976