Steric effects on the stereochemistry of copper complexes of 2,6-bis(pyrazol-1-ylmethyl)pyridines

Article abstract of DOI:10.1016/S0277-5387(02)00872-0

The stereochemical preferences of copper complexes of 2,6-bis-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L¹Me₂) and of 2,6-bis-(phenylpyrazol-1-ylmethyl)pyridine (L¹Ph) have been investigated. The single crystal X-ray structures of [Cu(OH₂₎₍L¹Me₂)](BF₄)₂ and [CuCl(HOMe)(L¹Me₂)]BF₄ show near-regular tetragonal geometries with one or two axial solvent and/or BF₄^- ligands. In contrast, [Cu(OH₂)₂(L¹Ph)](BF₄)₂ adopts an irregular geometry in the crystal mid-way between square-pyramidal and trigonal-bipyramidal. The single crystal X-ray structure of [Cu(NCMe)(L¹Me₂)]BF₄ exhibits a distorted tetrahedral geometries, while [Cu(L¹Ph)]BF₄ adopts a T-shaped stereochemistry. By a combination of UV-Vis, EPR and conductivity studies, the solution structures of [CuCl₂(L)], [CuCl(solv)(L)]BF₄ and [Cu(solv)_x(L)](BF₄)₂ (L = L¹Me₂, L¹Ph; solv = H₂O, MeCN; x = 1, 2) have, in many cases, been shown to be the same as in the crystalline state. The cyclic voltammograms of [Cu(OH₂)(L¹Me₂)](BF₄)₂ and [Cu(OH₂)₂(L¹Ph)](BF₄)₂ in MeCN/0.1 M NBuⁿ₄BF₄ exhibit chemically reversible Cu(II/I) couples.

Full text of DOI:10.1016/S0277-5387(02)00872-0

Polyhedron 21 (2002) 1031ꢁ1041
/
www.elsevier.com/locate/poly
Steric effects on the stereochemistry of copper complexes of
2,6-bis(pyrazol-1-ylmethyl)pyridines
Caroline L. Foster, Colin A. Kilner, Mark Thornton-Pett, Malcolm A. Halcrow *
School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
Received 4 December 2001; accepted 25 January 2002
Abstract
The stereochemical preferences of copper complexes of 2,6-bis-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L1Me2) and of 2,6-bis-
(phenylpyrazol-1-ylmethyl)pyridine (L1Ph) have been investigated. The single crystal X-ray structures of [Cu(OH2)(L1Me2)](BF4)2
ꢀ
and [CuCl(HOMe)(L1Me2)]BF4 show near-regular tetragonal geometries with one or two axial solvent and/or BF4 ligands. In
contrast, [Cu(OH2)2(L1Ph)](BF4)2 adopts an irregular geometry in the crystal mid-way between square-pyramidal and trigonal-
bipyramidal. The single crystal X-ray structure of [Cu(NCMe)(L1Me2)]BF4 exhibits a distorted tetrahedral geometries, while
[Cu(L1Ph)]BF4 adopts a T-shaped stereochemistry. By a combination of UVꢁ
/
Vis, EPR and conductivity studies, the solution
structures of [CuCl2(L)], [CuCl(solv)(L)]BF4 and [Cu(solv)x (L)](BF4)2 (Lꢂ
/
L1Me2, L1Ph; solvꢂ
/
H2O, MeCN; xꢂ1, 2) have, in
/
many cases, been shown to be the same as in the crystalline state. The cyclic voltammograms of [Cu(OH2)(L1Me2)](BF4)2 and
[Cu(OH2)2(L1Ph)](BF4)2 in MeCN/0.1 M NBu4nBF4 exhibit chemically reversible Cu(II/I) couples. # 2002 Elsevier Science Ltd. All
rights reserved.
Keywords: Copper complexes; Stereochemistry; X-ray structures; Steric properties
1. Introduction
This paper describes a crystallographic and spectro-
scopic investigation of the Cu(I) and Cu(II) chemistries
of two ligands, L1Me2 and L1Ph (Scheme 1), in the
presence and absence of a coordinating anion. Our
results complement data from Manoharan and Mu-
kherjee, who reported several compounds of type
Much of the biomimetic Cu(II) chemistry that has
been published over the past 15 years employs facially or
meridionally coordinating tris-N-donor ligands as pro-
tecting groups [1ꢁ
/
4]. These are intended to mimic the
OHꢀ, nꢂ
1; LꢂOH2, nꢂ2)
[CuX2(L1Me2)] (Xꢀ ꢂ
/
halide, pseudohalide, NO2ꢀ or
12], and
[Cu(II)(his)3L]nꢃ (Lꢂ
/
/
/
/
NO3ꢀ) while our own work was in progress [9ꢁ
/
centres found in many Type 2 copper [5,6], and all
Type 3 and multi-copper [7], proteins. However, despite
their utility in this regard, relatively few systematic
studies of the stereochemical preferences of Cu(II)
centres using this type of ligand have been carried out.
This is an important question since, in contrast to many
other biometals, the Cu(II) ion readily adopts a wide
range of stereochemistries [8]. This can make its
chemistry unpredictable and difficult to study, particu-
larly in the absence of strongly coordinating anions.
offer a good example of how the Cu(I) and Cu(II) ions
adapt their coordination environments in response to
steric crowding from the L1R protecting group. We are
aware of only a few similar studies involving other tris-
N donor ligands. The most relevant example is L2R,
which Karlin and Re´glier have shown to cleanly form
tetrahedral
[Cu(solv)2(L2R)]2ꢃ (solvꢂ
[Cu(solv)(L2R)]ꢃ
MeCN, H2O) complexes
and
tetragonal
/
with weakly coordinating anions like triflate and
perchlorate [13]. These stereochemistries resemble the
structures exhibited by Type 2 and 3 copper biosites,
which has contributed to the utility of L2R ligands in
biomimetic Cu chemistry [3,4]. The complexes of L3ꢁL9
/
* Corresponding author. Tel.: ꢃ
343-6565.
E-mail address: m.a.halcrow@chem.leeds.ac.uk (M.A. Halcrow).
/
44-113-343-6506; fax: ꢃ44-113-
/
with Cu(II) salts of weakly coordinating anions have
also been studied by Williams [14], Evans [15], and
0277-5387/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S 0 2 7 7 - 5 3 8 7 ( 0 2 ) 0 0 8 7 2 - 0

1032
C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ1041
/
Scheme 1. Ligands referred to in this study.
Bernauer [16]. However, L3ꢁ
dimeric complexes with Cu(I) that are not biomimeti-
/
L5 and L7R form helical
species was identical to that of 1, while its IR spectrum
demonstrated the presence of BF4ꢀ and L1Me2 only.
Hence, we tentatively formulate this second complex as
solvent-free [Cu(L1Me2)]BF4. In contrast to the above
reactions, treatment of [Cu(NCMe)4]BF4 with an equi-
molar amount of L1Ph in MeCN, followed by precipita-
tion with Et2O as before, cleanly afforded the pale
yellow air-stable compound [Cu(L1Ph)]BF4 (2).
Single crystals of formula [Cu(NCMe)(L1Me2)]BF4
(1) and [Cu(L1Ph)]BF4 (2) were grown by layering
solutions of the complexes in MeCN and MeNO2,
respectively, with Et2O under N2. The structure of 1
shows an irregular, distorted tetrahedral geometry at
Cu(1) (Fig. 1, Table 1), which is, however, similar to
those previously described for [Cu(PPh3)(L1Me2)]ClO4
and [{Cu(L1Me2)}2(m-dppe)](ClO4)2 [22]. Of particular
cally relevant [17].
2. Results and discussion
The ligand L1Me2 was prepared by the literature
method [18], while the new ligand L1Ph was synthesised
in good yield from 3{5}-phenylpyrazole [19] and 2,6-bis-
(chloromethyl)pyridine [20], following the literature
procedure for L1 [21].
2.1. Copper(I) complexes of L1R
Complexation of [Cu(NCMe)4]BF4 by 1 mole equiv.
of L1Me2 in MeCN under N2 gave an air-sensitive
yellow solution. Layering of this solution with Et2O
afforded air-stable yellow crystals of [Cu(NCMe)(L1-
Me2)]BF4 (1) in low yield, together with a larger amount
of unreacted [Cu(NCMe)4]BF4 which was removed
manually. Similar reactions in MeNO2 or CH2Cl2
afforded a mixture of 1 and a new pale yellow solid,
which we were unable to obtain in analytical purity from
this mixture. The FAB mass spectrum of this latter
interest are the unequal angles N(10)Ã
/
Cu(1)Ã
/
N(24) and
N(18)ÃCu(1)ÃN(24), and the fact that all four CuÃ
/
/
/N
bond lengths are significantly different. There are no
intramolecular steric contacts that would account for
these irregularities. However, the packing diagram of 1
shows there is a close contact between C(26) and F(30?)
˚
y, z) of 3.352(2) A, which
(symmetry operation x, ꢀ
/
1ꢃ
/
would appear to prevent the MeCN ligand from
occupying its idealised position in the coordination

C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ
/1041
1033
Fig. 1. View of the [Cu(NCMe)(L1Me2)]ꢃ complex cation in the
structure of 1, showing the atom numbering scheme employed.
Thermal ellipsoids are drawn at the 35% probability level. For clarity,
all C-bound H atoms have been omitted.
Fig. 2. View of the [Cu(L1Ph)]ꢃ complex cation in the structure of 2,
showing the atom numbering scheme employed. Details as for Fig. 1.
dark blue microcrystals. Upon prolonged drying in
vacuo, these transformed to a blue powder that analysed
Table 1
˚
Selected bond lengths (A) and angles (8) in the single crystal X-ray
consistently as [Cu(OH2)(L1Me2)](BF4)2×
/
H2O (3×/H2O).
structures of [Cu(NCMe)(L1Me2)]BF4 (1) and [Cu(L1Ph)]BF4 (2)
Since the crystallographic analysis of this material (see
below) showed only 1 mole equiv. of water, it is
uncertain whether the second mole of water absorbed
by the ‘dried’ solid is coordinated to the copper ion. A
1
2
Bond lengths
Cu(1)ÃN(2)
Cu(1)ÃN(10)
Cu(1)ÃN(18)
Cu(1)ÃN(24)
2.1198(12) Cu(1)ÃN(2)
2.1044(13) Cu(1)ÃN(10)
1.9922(13) Cu(1)ÃN(22)
1.9425(14)
2.108(2)
1.914(2)
1.9175(19)
similar reaction employing L1Ph gave a redꢁ
brown
/
crystalline solid [Cu(OH2)2(L1Ph)](BF4)2 (4). Green,
sparingly soluble [CuCl2(L1Me2)] (5) [9] and
[CuCl2(L1Ph)] (6) were also prepared, by treatment of
CuCl2 with the appropriate ligand in MeCN. Reaction
of these solids with 1 molar equiv. of AgBF4 in MeCN
Bond angles
N(2)ÃCu(1)ÃN(10)
N(2)ÃCu(1)ÃN(18)
N(2)ÃCu(1)ÃN(24)
N(10)ÃCu(1)ÃN(18) 120.84(5)
N(10)ÃCu(1)ÃN(24) 103.27(5)
N(18)ÃCu(1)ÃN(24) 121.04(6)
89.10(5) N(2)ÃCu(1)ÃN(10)
95.16(5) N(2)ÃCu(1)ÃN(22)
124.42(6) N(10)ÃCu(1)ÃN(22) 168.72(8)
94.74(8)
96.01(8)
yielded blue (Lꢂ
/
L1Me2) or green (Lꢂ
/
L1Ph) solutions,
which were evaporated to dryness. Recrystallisation of
the crude materials from MeOHꢁEt2O gave [CuCl(HO-
/
Me)(L1Me2)]BF4 (7) and [CuCl(OH2)(L1Ph)]BF4 (8) as
microcrystalline solids.
sphere. Hence, these molecular distortions can probably
be attributed to intermolecular steric contacts.
The complex cation in 2 has a regular T-shaped
Single crystals of formula [Cu(OH2)(L1Me2)](BF4)2
(3) and [CuCl(HOMe)(L1Me2)]BF4 (7) were grown by
vapour diffusion from MeOHꢁ
[Cu(OH2)2(L1Ph)](BF4)2 (4) were similarly obtained
from MeNO2ꢁEt2O. The molecular structures of 3
and 7 are rather similar. Complex 3 contains a near-
regular square-planar [Cu(OH2)(L1Me2)]2ꢃ centre (Fig.
3, Table 2; structure A in Scheme 2) with a t index [23]
of 0.10, which is very close to the ideal value of 0 for a
regular square-pyramid. There are weak axial interac-
tions between Cu(1) and both BF4ꢀ anions to yield a
/
Et2O. Crystals of
geometry (Fig. 2, Table 1). The bonds Cu(1)Ã
Cu(1)ÃN(22) are now crystallographically equal, while
the angle N(10)ÃCu(1)ÃN(22) has increased to
168.74(8)8, compared with the equivalent angle in 1 of
/
N(10) and
/
/
/
/
120.84(5)8. Despite this large variation in trans-NÃ
/
CuÃ
/
N angle, the chelate bite angle of the L1R ligand varies
only slightly in the two structures, from an average of
92.14(7)8 in 1 to 95.36(11)8 in 2. Rather, these differ-
ences reflect differing chelate ring conformations in the
structures, which are chair-like in 1 and boat-like in 2.
[4ꢃ
Cu(1)ꢀ ꢀ ꢀF(34)ꢂ
/
2] tetragonal Cu(II) ion [Cu(1)ꢀ ꢀ ꢀF(26)ꢂ
/
2.531(2),
˚
3.049(3) A]. Both anions are also in-
/
volved in hydrogen-bonding to the aqua ligand. One
anion interacts with the aqua ligand on the same cation
to which it forms an axial interaction. The other
(disordered) anion forms hydrogen bonds to a neigh-
bouring cation, yielding a 1-D polymeric lattice com-
2.2. Syntheses and crystal structures of copper(II)
complexes of L1R
Complexation of hydrated Cu(BF4)2 by an equimolar
amount of L1Me2 in MeNO2, followed by diffusion of
Et2O into the resultant solution, yielded hygroscopic
posed of alternating Cuꢀ ꢀ ꢀF and Fꢀ ꢀ ꢀHÃ/O interactions.

1034
C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ1041
/
[23]. The four protons on the water ligands in 4 are
each hydrogen bonded to a different BF4ꢀ anion,
forming a 1-D chain polymer motif in the crystal.
2.3. Conductivity, UVꢁ/Vis and EPR measurements
Solution UVꢁVis and conductivity data for the Cu(II)
/
compounds in this study, in both MeCN and MeNO2
solutions, are listed in Table 3. Conductivity measure-
ments for all of the Cu(II) complexes in this study were
consistent with their solid state molecular structures.
Hence, complexes 5 and 6 exhibit molar conductivities
consistent with their being non-electrolytes in both these
solvents, while 7 and 8 are clearly 1:1 electrolytes and 3
and 4 are 2:1 electrolytes [24]. This demonstrates that
Clꢀ-dissociation does not take place upon dissolution
of the chloride-containing complexes in MeCN or
MeNO2, which is consistent with an earlier study of 5
in dmf solution [9].
Fig. 3. View of the [Cu(OH2)(L1Me2)](BF4)2 moiety in the structure of
3, showing the atom numbering scheme employed. Details as for Fig.
1. For clarity, only one orientation of the disordered BF4ꢀ anion
B(25)ÃF(29) is shown.
/
The visible spectra of 3ꢁ
/
8 each exhibit a single d ꢁ
/d
band (Table 3). The d ꢁd spectra of 5ꢁ
/
/7 are essentially
identical in MeCN and MeNO2. This shows that they
adopt the same molecular structures in these two
solvents, and that dissociation of Clꢀ or the L1R ligand
does not take place upon dissolution. However, the d ꢁd
/
maximum for 8 lies at a slightly lower wavelength in
MeNO2 than in MeCN. This suggests that, although the
coordination geometry of 8 probably does not vary
between the two solvents, solvent coordination is more
important to the solution structure of 8 than 7.
Unsurprisingly, the d ꢁ
solvent dependent. For 3, 4 and 8, the d ꢁ
/
d maxima of 3 and 4 are very
d maxima lie at
/
longer wavelength in MeCN than in MeNO2, which is
consistent with the relative positions in the spectro-
chemical series of MeCN and H2O [25] (the probable
‘solv’ ligand in MeNO2, since MeNO2 itself is an
extremely poor ligand [26]).
Fig. 4. View of the [Cu(OH2)2(L1Ph)]2ꢃ complex dication in the
structure of 4, showing the atom numbering scheme employed. Details
as for Fig. 1.
As solids, the X-band EPR spectra of 4ꢁ6 and 8 are
/
well-resolved into a clearly rhombic pattern, the g-
values for each of these compounds being quite similar
(Table 4). We, therefore, propose that 6 and 8 adopt
structure B (Scheme 2) in the solid, as do 4 and 5 in the
crystal [10]. The solid state EPR spectrum of 7 is distinct
In 7, the copper ion also adopts structure A (Scheme 2),
with an apical MeOH ligand [Cu(1)Ã
/
O(25)ꢂ
/
2.362(3)
˚
A, tꢂ
/
0.11] (Fig. 5, Table 2). The cations in the crystal
are arranged into dimers, by hydrogen-bonding between
the MeOH hydroxyl proton and a Clꢀ ligand of a
from the others and is clearly axial, with the g ꢀ
/
gÞ ꢀ
/
ge
Š
pattern and an A {63,65Cu} value typical of a tetragonal
Š
{dx ꢀy
}1 or {dxy}1 Cu(II) species [27]. This is consistent
2
2
neighbouring cation related by 1ꢀ
/
x, ꢀ
/
y, 1ꢀz.
/
/
In contrast to the L1Me2 compounds, the copper ion
in 4 has an irregular five-coordinate structure, which
corresponds to structure B in Scheme 2 (Fig. 4, Table 2).
This structure could be considered as trigonal-bipyra-
with the crystal structure of this complex. The powder
EPR spectrum of 3 is broad and unresolved.
The frozen solution EPR spectra of 6 and 8 in 10:1
MeCN:toluene and 10:1 MeNO2:toluene are isotropic
midal with the pyrazole N-donors axial [N(10)Ã
N(22)ꢂ177.84(6)8], or as square-pyramidal with the
pyridine N-donor apical [Cu(1)Ã
/
Cu(1)Ã
/
and uninformative. In contrast, 3ꢁ
axial or pseudo-axial frozen solution EPR spectra with
/
5 and 7 all exhibit
/
g ꢀ
/
gÞ ꢀ
/
ge, that are again consistent with {dx ꢀy
}1 or
2
2
˚
N(2)ꢂ2.1879(15) A].
The t index for this compound is in fact 0.46, almost
/
/
/
Š
{dxy}1 Cu(II) species (Table 4) [27]. Hence, it seems clear
that 3 and 7 both retain their crystallographic tetragonal
geometry upon dissolution. However, there are some
exactly midway between the limiting values for a regular
square-pyramid (tꢂ
/
0) or trigonal-bipyramid (tꢂ1)
/

C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ
/1041
1035
Table 2
1
Selected bond lengths (A) and angles (8) in the single crystal X-ray structures of [Cu(OH2)(L Me2)](BF4)2 (3), [Cu(OH2)2(L1Ph)](BF4)2 (4) and
˚
[CuCl(HOMe)(L1Me2)]BF4 (7)
3
4
7
Bond lengths
Cu(1)ÃN(2)
Cu(1)ÃN(10)
Cu(1)ÃN(18)
Cu(1)ÃO(24)
Cu(1)ÃF(26)
Cu(1)ÃF(34)
2.011(3)
1.963(3)
1.974(3)
1.958(3)
2.531(2)
3.049(3)
Cu(1)ÃN(2)
Cu(1)ÃN(10)
Cu(1)ÃN(22)
Cu(1)ÃO(32)
Cu(1)ÃO(33)
2.1879(15)
1.9935(15)
1.9987(16)
2.0194(16)
2.0276(16)
Cu(1)ÃN(2)
Cu(1)ÃN(10)
Cu(1)ÃN(18)
Cu(1)ÃCl(24)
Cu(1)ÃO(25)
2.063(3)
2.025(3)
2.016(3)
2.2573(10)
2.362(3)
Bond angles
N(2)ÃCu(1)ÃN(10)
N(2)ÃCu(1)ÃN(18)
N(2)ÃCu(1)ÃO(24)
N(2)ÃCu(1)ÃF(26)
N(2)ÃCu(1)ÃF(34)
N(10)ÃCu(1)ÃN(18)
N(10)ÃCu(1)ÃO(24)
N(10)ÃCu(1)ÃF(26)
N(10)ÃCu(1)ÃF(34)
N(18)ÃCu(1)ÃO(24)
N(18)ÃCu(1)ÃF(26)
N(18)ÃCu(1)ÃF(34)
O(24)ÃCu(1)ÃF(26)
O(24)ÃCu(1)ÃF(34)
F(26)ÃCu(1)ÃF(34)
90.06(12)
89.11(12)
172.36(14)
101.11(10)
102.25(9)
178.64(12)
90.58(14)
91.42(10)
81.81(10)
90.10(14)
89.80(10)
97.31(10)
86.49(12)
70.32(11)
155.65(7)
N(2)ÃCu(1)ÃN(10)
N(2)ÃCu(1)ÃN(22)
N(2)ÃCu(1)ÃO(32)
N(2)ÃCu(1)ÃO(33)
N(10)ÃCu(1)ÃN(22)
N(10)ÃCu(1)ÃO(32)
N(10)ÃCu(1)ÃO(33)
N(22)ÃCu(1)ÃO(32)
N(22)ÃCu(1)ÃO(33)
O(32)ÃCu(1)ÃO(33)
90.12(6)
91.97(6)
97.49(7)
112.24(6)
177.84(6)
89.44(7)
87.60(7)
89.73(7)
92.12(7)
150.12(7)
N(2)ÃCu(1)ÃN(10)
N(2)ÃCu(1)ÃN(18)
N(2)ÃCu(1)ÃCl(24)
N(2)ÃCu(1)ÃO(25)
N(10)ÃCu(1)ÃN(18)
N(10)ÃCu(1)ÃCl(24)
N(10)ÃCu(1)ÃO(25)
N(18)ÃCu(1)ÃCl(24)
N(18)ÃCu(1)ÃO(25)
Cl(24)ÃCu(1)ÃO(25)
84.28(12)
89.58(12)
174.32(9)
91.52(11)
168.02(13)
93.15(9)
103.70(12)
92.01(10)
86.70(12)
94.02(8)
Scheme 2. Coordination geometries exhibited by [CuXY(L1R)]nꢃ
complexes.
differences between the EPR spectra of 4 and 5 in these
two phases. Therefore, the detailed stereochemistries of
4ꢁ6 and 8 in solution are presently uncertain. Impor-
/
tantly, for all complexes where the comparison could be
made, these spectra are essentially invariant between
solvents, suggesting that changing the identity of solvent
Fig. 5. View of the [CuCl(HOMe)(L1Me2)]ꢃ complex cation in the
structure of 7, showing the atom numbering scheme employed. Details
as for Fig. 1.
ligands to the [CuClx(solv)2ꢀx(L1R)](2ꢀx)ꢃ (xꢂ
/
0ꢁ2)
/
centres barely perturbs the coordination geometry at
Cu.
of Cu(II) and Cu(I) complexes containing each ligand
were run for comparison; in each case, the CVs obtained
from the oxidised and reduced congeners of a given
couple showed only small differences (Table 5).
2.4. Electrochemistry
For each Cu(II) complex 3 and 4, a chemically
reversible Cu(II/I) couple was obtained. However, plots
A preliminary voltammetric study was carried out in
MeCN/0.1 M NBun4PF6 at 293 K, to elucidate the
of Ip versus n1/2 (nꢂ
not give a straight line, showing that these couples are
/
scan rate) for these processes did
potentials of the [Cu(solv)xL]2ꢃ/[Cu(solv)yL]ꢃ (Lꢂ
/
L1Me2, L1Ph) couples. Cyclic voltammograms (CVs)

1036
C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ1041
/
Table 3
Conductivity and UVꢁVis spectroscopic data for the Cu(II) compounds in this study (293 K)
/
Solvent
LM, Vꢀ1 cm2 molꢀ1
lmax, nm (omax, Mꢀ1 cmꢀ1
)
[Cu(OH2)(L1Me2)](BF4)2×H2O (3×H2O)
[Cu(OH2)2(L1Ph)](BF4)2 (4)
[CuCl2(L1Me2)] (5)
MeCN
MeNO2
MeCN
MeNO2
MeCN
MeNO2
MeCN
MeNO2
MeCN
MeNO2
MeCN
MeNO2
219
132
207
142
8
260 (6,000), 319 (sh), 645 (69)
612 (70)
254 (39,000), 329 (2,200), 458 (280), 802 (70)
689 (70)
267 (6,100), 345 (1,200), 768 (180)
766 (170)
6
13
[CuCl2(L1Ph)] (6)
254 (87,000), 343 (sh), 453 (150), 807 (139)
808 (135)
8
[CuCl(HOMe)(L1Me2)]BF4 (7)
[CuCl(OH2)(L1Ph)]BF4 (8)
128
79
268 (6,800), 340 (560), 692 (80)
688 (83)
112
64
248 (34,600), 332 (2,800), 413 (sh), 752 (142)
739 (145)
Table 4
X-band EPR data for the Cu(II) complexes in this study
g1
g2
g3
A1
[Cu(OH2)(L1Me2)](BF4)2×H2O (3×H2O)
[Cu(OH2)2(L1Ph)](BF4)2 (4)
[CuCl2(L1Me2)] (5)
Powder
MeCN
MeNO2
Powder
MeCN
MeNO2
Powder
MeCN
MeNO2
Powder
MeCN
MeNO2
Powder
MeCN
MeNO2
Powder
MeCN
MeNO2
2.07
2.28
2.26
2.30
2.33
2.31
2.26
2.29
2.07
2.07
2.15
2.12
2.13
2.10
2.10
2.12
2.09
2.14
2.14
2.06
2.08
2.08
2.10
2.14
2.14
2.07
2.07
2.04
2.12
2.13
2.03
2.10
174
184
144
143
161
[CuCl2(L1Ph)] (6)
2.28
2.04
[CuCl(HOMe)(L1Me2)]BF4 (7)
[CuCl(OH2)(L1Ph)]BF4 (8)
2.26
2.27
2.27
2.28
2.06
2.08
2.08
2.04
170
166
172
All spectra were obtained at 120 K. Hyperfine couplings are to 63,65Cu and are in G. All solution spectra were run in solvents containing 10%
toluene to aid glassing. Spectra with only one g value quoted are isotropic.
not electrochemically reversible. This probably reflects
the kinetics of solvent coordination or decoordination
that take place following Cu-based redox at these
centres. The 1/3 couple is approximately 0.6 V more
positive than the Cu(II/I) reduction previously reported
for 5 in dmf [9], consistent with the presence of more
strongly donating Clꢀ coligands in the latter com-
pound. Interestingly, the 2/4 couple is approximately
appear to depend upon the identity of both ‘R’ and the
exogenous ligands ‘solv’. For the Cu(I) complexes, the
ability of a [Cu(L1R)]ꢃ fragment to bind exogenous
ligands is dependent on the identity of ‘R’. This is
Table 5
Cyclic voltammetric data for the complexes in this study (MeCN/0.1 M
NBun4 BF4, 298 K, nꢂ100 mV sꢀ1
)
ꢃ0.15 V more positive than the 1/3 couple, showing that
/
the identity of the L1R ‘R’ substituents has a substantial
effect on the redox chemistry of the coordinated Cu ion.
E1/2 {Cu(II/I)} Epc{Cu(I/
(V) (DEp, mV) 0)} (V)
[Cu(NCMe)(L1Me2)]BF4 (1)
[Cu(L1Ph)]BF4 (2)
ꢃ0.14 (220)
ꢃ0.29 (88)
ꢀ1.18
ꢀ0.91
ꢀ1.20
ꢀ0.89
3. Concluding remarks
[Cu(OH2)(L1Me2)](BF4)2×H2O (3×H2O) ꢃ0.18 (244)
[Cu(OH2)2(L1Ph)](BF4)2 (4)
ꢃ0.33 (146)
Within the [Cu(solv)x(L1R)]2ꢃ/[Cu(solv)y(L1R)]ꢃ
system there are substantial structural variations, which
All potentials quoted vs. an internal ferrocene/ferrocenium standard.

C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ
/1041
1037
presumably a steric effect, since the greater basicity of
3,5-dimethylpyrazole compared with 3{5}-phenylpyra-
zole [28] suggests that the [Cu(L1Ph)]ꢃ moiety should be
less electron-rich [29], and so more likely to bind
exogenous ligands, than [Cu(L1Me2)]ꢃ. This being the
case, it is uncertain whether the lower oxidation
potential of 1 compared with 2 is driven by the more
donating character of L1Me2 compared with L1Ph [29],
or by the higher co-ordination number at Cu in 1.
Combining our results with earlier work (Table 4), it
4. Experimental
Unless stated otherwise, all manipulations were
performed in air using commercial grade solvents. 2,6-
Bis-(chloromethyl)pyridine [20], 3-phenylpyrazole [19],
L1Me2 [18], [Cu(NCCH3)4]BF4 [30] and [CuCl2(L1Me2)]
(5) [9,10] were prepared by the literature procedures.
Cu(BF4)2×/6H2O (Avocado), KH (Aldrich) and all
solvents were used as supplied, except that diglyme
was dried over sodium before use. Microanalytical, mass
spectrometric, UVꢁVis, EPR and conductivity data for
the complexes are listed in Tables 3, 4 and 7.
/
is clear that [Cu(II)XY(L1R)]nꢃ (X, Yꢂ
dohalide or solvent, nꢂ0ꢁ2) complexes can adopt one
/
halide, pseu-
/
/
of two limiting geometries; tetragonal, with Y apical
(structure A in Scheme 2); or, tetragonal with the L1R
pyridyl group apical (structure B). The available data
suggest that these structural types can be distinguished
by EPR spectroscopy (Table 6). All structurally authen-
4.1. Synthesis of 2,6-bis-({3-phenylpyrazol-1-
yl}methyl)pyridine (L1Ph)
A mixture of 3-phenylpyrazole (15.9 g, 0.11 mol) and
NaH (4.0 g, 0.11 M) in dry THF (50 cm3) was stirred at
60 8C under N2 for 30 min. 2,6-Bis-(chloromethyl)pyr-
idine (9.7 g, 0.055 mol) was then added, and the mixture
stirred at 60 8C for 24 h. The solvent was removed
under reduced pressure and the residue taken up in
ticated type A complexes exhibit axial g ꢀ
/
gÞ :2.07
/
Š
powder EPR spectra, where these can be clearly
resolved, while all known type B complexes show
strongly rhombic powder EPR spectra, with g352.04.
/
Bulky L1R ‘R’ substituents appear to favour structure
B, since EPR data show that all of the L1Ph-containing
complexes in this work exhibit structure B in the
solid. Most of the L1Me2 complexes follow the trend
expected on steric grounds, in that [CuXY(L1Me2)]
chloroform (3ꢄ
50 cm3). The combined organic frac-
/
tions were washed with water and saturated aqueous
NaCl, then dried over MgSO4. The filtered solution was
evaporated to dryness to leave an off-white solid which
was recrystallised from thfꢁ
(Found: C, 76.7; H, 5.3; N, 18.1; Calc. for C25H21N5: C,
76.4; H, 5.4; N, 17.8%). M.p. 98ꢁ100 8C. EI mass
pzPh]ꢃ, 157
/
Et2O. Yield 15.0 g, 70%
(Xꢂ
/
YꢂCl, Br) adopt structure B while those com-
/
plexes containing smaller N- or O-donor X and Y
ligands exhibit structure A. However, the anomalous
observation that [Cu(N3)2(L1Me2)] is a structure B
complex [9,12] suggests that electronic, as well as steric,
factors might play a role in the stereochemistry of
/
spectrum: m/z 391 [M]ꢃ, 248 [Mꢀ
/
[CH2pzPh]ꢃ, 144 [HpzPh]ꢃ, 77 [C5H3N]ꢃ. NMR spectra
1
({CD3}2SO, 293 K): H; d 7.93 (d, 2.3 Hz, 2H, Pz H5),
7.77 (m, 5H, Ph H2/6ꢃ
/
Py H4), 7.38 (m, 6H, Ph H3/5ꢃ
/
Cu(II)ꢁ
/
L1R complexes.
Ph H4), 6.98 (d, 7.8 Hz, 2H, Py H3/5), 6.78 (d, 2.3 Hz,
Table 6
Structural types and powder EPR spectra exhibited by crystallographically characterised Cu(II) 2,6-bis(pyrazolyl-1-ylmethyl)pyridine complexes
a
b
Structure type
t
g1
g2
g3
Reference
c
[Cu(OH2)(L1Me2)](BF4)2 (3)
[Cu(ONO2)2(L1Me2)]
A
A
A
A
A
A
B
B
B
B
B
0.10
0.10
0.11
0.13
0.14
0.26
0.14
0.16
0.37
0.46
0.45
2.07
2.067
2.06
This work
[10]
c
c
[CuCl(HOMe)(L1Me2)]BF4 (7)
[Cu(ONO)(OClO3)(L1Me2)]
2.26
2.200
2.06
2.078
This work
[12]
[9]
2.078
2.076
2.085
2.105
2.092
2.105
[Cu(L10)(L1Me2)](ClO4)2
d
[Cu(NCS)2(L1Me2)]
[CuBr2(L1Me2)]
2.258
2.236
2.252
2.236
2.30
2.085
2.041
2.027
2.041
2.04
[10,11]
[10]
[CuCl2(L1Me2)]
This work, [10]
[9,12]
[Cu(N3)2(L1Me2)]
[Cu(OH2)2(L1Ph)](BF4)2 (4)
2.15
e
This work
[20]
d
[Cu(NCS)2(L11)]
a
Scheme 2.
Ref. [23].
b
c
Broad, apparently isotropic spectrum.
Scheme 1.
Not reported.
d
e

1038
C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ1041
/
Table 7
Analytical and selected FAB mass spectrometric data for the complexes in this study
Found (Calc.)
%C
Colour
%H
%N
m/z
[Cu(NCMe)(L1Me2)]BF4 (1)
[Cu(L1Ph)]BF4 (2)
[Cu(OH2)(L1Me2)](BF4)2×H2O (3×H2O)
[Cu(OH2)2(L1Ph)](BF4)2 (4)
[CuCl2(L1Me2)] (5)
[CuCl2(L1Ph)] (6)
[CuCl(HOMe)(L1Me2)]BF4 (7)
[CuCl(OH2)(L1Ph)]BF4 (8)
Yellow
Pale yellow
Blue
46.8 (46.9)
55.3 (55.4)
35.7 (35.9)
45.0 (45.2)
47.3 (47.5)
56.0 (56.9)
42.1 (42.1)
50.6 (50.4)
5.1 (5.0)
3.9 (3.9)
4.2 (4.4)
3.7 (3.8)
4.9 (4.9)
3.9 (4.0)
4.8 (4.9)
4.1 (3.9)
17.6 (17.3)
13.2 (12.9)
12.6 (12.3)
10.5 (10.5)
16.5 (16.3)
13.5 (13.3)
14.3 (13.6)
11.7 (11.8)
358
454
377, 358
473, 454
393, 358
489, 454
393, 358
489, 454
Red-brown
Green
Green
Blue
Brown
2H, Pz H4), 5.50 (s, 4H, CH2). 13C; d 157.4 (Py C2/6),
151.1 (Pz C3), 138.0 (Py C4ꢃPz C5), 133.9 (Ph C1),
129.7 (Ph C2/6), 127.2 (Ph C3/5), 125.0 (Ph C4), 120.7 (Py
3/5), 103.3 (Pz C4), 57.6 (CH2).
recrystallised from MeNO2ꢁEt2O to give very hygro-
scopic blue blocks. Yield 0.29 g, 61%.
/
/
C
4.5. Synthesis of [2,6-bis-({3-phenylpyrazol-1-
yl}methyl)pyridine]diaquacopper(II) ditetrafluoroborate
(4)
4.2. Synthesis of acetonitrile[2,6-bis-({3,5-
dimethylpyrazol-1-yl}methyl)pyridine]copper(I)
tetrafluoroborate (1)
A mixture of L1Ph (0.25 g, 6.4ꢄ
/
10ꢀ4 mol) and
Cu(BF4)2×
/
6H2O (0.22 g, 6.4ꢄ
/
10ꢀ4 mol) in MeNO2 (25
cm3) was stirred for 15 min at r.t., affording a green
solution which was concentrated to approximately 5 cm3
and filtered. Vapour diffusion of Et2O into this solution
A solution of L1Me2 (0.25 g, 8.4ꢄ
/
10ꢀ4 mol) and
[Cu(NCMe)4]BF4 (0.26 g, 8.4ꢄ
/
10ꢀ4 mol) in MeCN (25
cm3) was stirred under N2 for 10 min at room
temperature (r.t.). The yellow solution was concentrated
to approximately 5 cm3 and layered with Et2O, afford-
ing a mixture of pale yellow needles and colourless
blocks that were separated manually for analysis. The
colourless crystals were identified as [Cu(NCMe)4]BF4
by comparison with a genuine sample. Yield of yellow
crystals that were sufficiently large to separate by hand
yielded redꢁbrown cubes. Yield 0.31 g, 73%.
/
4.6. Synthesis of dichloro[2,6-bis-({3-phenylpyrazol-1-
yl}methyl)pyridine]copper(II) (6)
A suspension of L1Ph (0.66 g, 1.7ꢄ
/
10ꢀ3 mol) and
CuCl2 (0.22 g, 1.7ꢄ
/
10ꢀ3 mol) in MeCN (30 cm3) was
0.064 g, 8%. IR spectrum (Nujol): 2310w, 2275w cmꢀ1
.
stirred for 1 h at r.t., affording a green precipitate. This
was filtered, washed with MeCN and Et2O, and dried in
vacuo. This product was analysed without further
purification. Yield 0.58 g, 65%.
4.3. Synthesis of [2,6-bis-({3-phenylpyrazol-1-
yl}methyl)pyridine]copper(I) tetrafluoroborate (2)
4.7. Synthesis of chloro[2,6-bis-({3,5-dimethylpyrazol-1-
yl}methyl)pyridine](methanol)copper(II)
tetrafluoroborate (7)
A solution of L1Ph (0.25 g, 6.4ꢄ
/
10ꢀ4 mol) and
[Cu(NCMe)4]BF4 (0.20 g, 6.4ꢄ
/
10ꢀ4 mol) in MeNO2
(25 cm3) was stirred under N2 for 10 min at r.t. The
yellow solution was concentrated to approximately 5
cm3 and layered with Et2O, affording pale yellow
needles. Yield 0.16 g, 47%.
A solution of 5 (0.36 g, 8.4ꢄ
/
10ꢀ4 mol) and AgBF4
(0.16 g, 8.4ꢄ
/
10ꢀ4 mol) in MeCN (25 cm3) was stirred
for 2 h at r.t. The blue solution was filtered, and
evaporated to dryness. Recrystallisation of the residue
4.4. Synthesis of [2,6-bis-({3,5-dimethylpyrazol-1-
yl}methyl)pyridine]aquacopper(II) ditetrafluoroborate
(3)
from MeOHꢁEt2O yielded dark blue microcrystals.
Yield 0.17 g, 40%.
/
4.8. Synthesis of chloro[2,6-bis-({3-phenylpyrazol-1-
yl}methyl)pyridine]aquacopper(II) tetrafluoroborate
(8)
A solution of L1Me2 (0.25 g, 8.4ꢄ
/
10ꢀ4 mol) and
Cu(BF4)2×
/
6H2O (0.29 g, 8.4ꢄ
/
10ꢀ4 mol) in MeNO2 (25
cm3) was stirred for 15 min at r.t. The resultant blue
solution was concentrated to approximately 5 cm3 and
filtered. Vapour diffusion of Et2O into this solution gave
a sticky blue solid, which was dried over P2O5 and
Method as for 7, using 6 (0.44 g, 8.4ꢄ
product formed green microcrystals from MeOHꢁ
which became brown upon drying. Yield 0.16 g, 52%.
/
10ꢀ4 mol). The
Et2O,
/

C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ
/1041
1039
4.9. Single crystal X-ray structure determinations
4.13. X-ray structure determination of
[CuCl(HOCH3)(L1Me2)]BF4 (7)
Single crystals of X-ray quality of [Cu(NCMe)-
(L1Me2)]BF4 (1) were grown by diffusion of ether into
a solution of the complex in MeCN. Crystals of
[Cu(L1Ph)]BF4 (2) and [Cu(OH2)2(L1Ph)](BF4)2 (4)
During refinement, the BF4ꢀ anion was found to be
disordered over three equally occupied orientations. All
˚
F distances were restrained to 1.36(2) A, and non-
BÃ
/
bonded Fꢀ ꢀ ꢀF distances within a given disorder orienta-
were similarly grown from MeNO2ꢁ
[Cu(OH2)(L1Me2)]BF4 (3) and [CuCl(HOMe)(L1Me2)]-
BF4 (7) from MeOHꢁEt2O. Experimental details from
/Et2O, and of
˚
tion to 2.22(2) A. All wholly occupied non-H atoms
were refined anisotropically. The hydroxyl H atom of
the methanol ligand was located in the difference map
and allowed to refine freely; all other H atoms were
placed in calculated positions and refined using a riding
model.
/
the structure determinations are given in Table 8. All
structures were solved by direct methods (SHELXS-97
[31]) and refined by full-matrix least-squares on F2
(SHELXL-97 [32]), with H atoms placed in calculated
positions.
4.14. Other measurements
Infra-red spectra were obtained as Nujol mulls
pressed between KBr windows, between 400 and 4000
cmꢀ1 using a Nicolet Avatar 360 spectrophotometers.
4.10. X-ray structure determinations of
[Cu(NCMe)(L1Me2)]BF4 (1) and [Cu(L1Ph)]BF4
(2)
UVꢁ
/
Vis spectra were obtained with a PerkinꢁElmer
/
Lambda 900 spectrophotometer, operating between
1100 and 200 nm, in 1 cm quartz cells. All NMR
spectra were run on a Bruker ARX250 spectrometer,
operating at 250.1 MHz (1H) and 62.9 MHz (13C).
Electron impact (EI) and positive ion fast atom bom-
bardment (FAB) mass spectra were performed on a VG
AutoSpec spectrometer, the FAB spectra employing a 3-
NOBA matrix. CHN microanalyses were performed by
the University of Leeds School of Chemistry micro-
analytical service. Melting points are uncorrected. X-
band EPR spectra were obtained using a Bruker
ER200D spectrometer.
No disorder was detected during the refinement of
either of these structures, and no restraints were applied.
All non-H atoms were refined anisotropically, and all H
atoms were placed in calculated positions and refined
using a riding model.
4.11. X-ray structure determination of
[Cu(OH2)(L1Me2)](BF4)2 (3)
ꢀ
During refinement, one BF4 anion was found to be
disordered by rotation about one BÃ/F bond. The
Conductivity measurements were obtained with a
Jenway 4310 analyser, at concentrations of approxi-
disordered F atoms were modelled over two equally
occupied orientations. No restraints were applied. All
mately 5ꢄ
10ꢀ3 mol dmꢀ3. All electrochemical mea-
/
non-H atoms with occupancy
ꢀ0.5 were refined
/
surements were carried out using an Autolab
PGSTAT30 voltammetric analyser, in MeCN contain-
ing 0.1 M NBun4BF4 as supporting electrolyte. Cyclic
voltammetric experiments involved the use of platinum
working and counter electrodes and a silver wire
reference electrode; all potentials quoted are referenced
to an internal ferrocene/ferrocenium standard and were
anisotropically. The H atoms for the aqua ligand were
located in the difference map and allowed to refine
freely; all other H atoms were placed in calculated
positions and refined using a riding model.
obtained at a scan rate of 100 mV sꢀ1
.
4.12. X-ray structure determination of
[Cu(OH2)2(L1Ph)](BF4)2 (4)
During refinement, one BF4ꢀ anion was found to be
disordered over three orientations, with occupancy 0.50,
5. Supplementary material
0.30 and 0.20. All BÃ
/
F distances in the disordered anion
˚
Full crystallographic data for the structure analyses in
this study are available on request from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cam-
were restrained to 1.38(2) A, and non-bonded Fꢀ ꢀ ꢀF
distances within a given disorder orientation to 2.25(2)
˚
A. All non-H atoms with occupancy ]
/0.5 were refined
bridge CB2 1EZ, UK (fax: ꢃ44-1223-336033; e-mail:
/
anisotropically. The H atoms for the aqua ligands were
located in the difference map and allowed to refine
freely; all other H atoms were placed in calculated
positions and refined using a riding model.
deposit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk). The CCDC deposition numbers are
165783 (1), 165785 (2), 165786 (3), 165787 (4) and
165788 (7).

1040
C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ1041
/
Table 8
Experimental details for the single crystal structure determinations in this study
[Cu(NCMe)(L1Me2)]BF4 (1) [Cu(L1Ph)]BF4 (2)
[Cu(OH2)(L1Me2)](BF4)2 (3)
Formula
Mr
C19H24BCuF4N6
486.79
C25H21BCuF4N5
541.82
C17H23B2CuF8N5O
550.56
Crystal size (mm)
Crystal class
Space group
0.66ꢄ0.45ꢄ0.12
monoclinic
P21/c
0.27ꢄ0.12ꢄ0.12
orthorhombic
P212121
0.39ꢄ0.30ꢄ0.24
monoclinic
P21/c
˚
a (A)
15.1864(2)
7.6452(1)
23.7158(3)
8.0834(2)
13.6690(3)
21.1714(5)
13.9278(4)
10.8144(4)
19.4236(6)
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
V (A )
Z
m (Mo Ka) (mmꢀ1
T (K)
Diffractometer
129.4710(5)
ꢁ
/
129.485(2)
3
˚
2125.53(5)
4
1.081
2339.27(10)
4
0.990
2257.95(14)
4
1.053
)
150(2)
Nonius KappaCCD area-detector
˚
Radiation, l (A)
Graphite-monochromated Mo Ka,
0.71073
34397
5328
Measured reflections
Independent reflections
Rint
81608
4871
0.060
20524
4963
0.071
0.066
Absorption correction
Min. transmission
Max. transmission
Observed reflections
[I ꢀ2s(I)]
Multi-scan
0.78
0.89
0.54
0.88
4457
0.68
0.79
4066
4642
Range in 2u (8)
Range in h
Range in k
3.452u 555.1
ꢀ195h 519
ꢀ95k 59
ꢀ305l 530
289/0
3.852u 554.9
ꢀ105h 510
ꢀ175k 517
ꢀ275l 527
326/0
7.752u 555.0
ꢀ185h 518
ꢀ145k 513
ꢀ255k 525
333/0
Range in l
Parameters/restraints
R(F) a, wR(F2)
Goodness-of-fit
Weighting scheme
b
0.029, 0.080
1.047
0.035, 0.078
1.031
wꢂ1/[s2(Fo2)ꢃ(0.0381P)2ꢃ0.4381P]
0.063, 0.166
1.078
c
wꢂ1/
wꢂ1/
[s2(Fo2)ꢃ(0.0397P)2ꢃ1.0105P]
0.37/ꢀ0.58
[s2(Fo2)ꢃ(0.0352P)2ꢃ0.6207P]
0.60/ꢀ0.73
ꢀ3
˚
Dr(max/min) (e A
Flack parameter
)
0.34/ꢀ0.42
ꢀ0.009(10)
ꢁ/
ꢁ/
[Cu(OH2)2(L1Ph)](BF4)2 (4)
[CuCl(HOMe)(L1Me2)]BF4 (7)
Formula
Mr
C25H25B2CuF8N5O2
664.66
C18H25BClCuF4N5O
513.23
Crystal size (mm)
Crystal class
Space group
0.30ꢄ0.24ꢄ0.24
monoclinic
P21/c
0.51ꢄ0.30ꢄ0.18
triclinic
¯
P1
˚
a (A)
18.3780 (3)
8.9210(2)
16.5700(3)
10.2687(1)
10.9259(1)
˚
b (A)
˚
c (A)
11.9993(2)
89.531(1)
a (8)
b (8)
g (8)
94.037(1)
64.997(1)
70.373(1)
1135.01(2)
3
˚
V (A )
Z
2709.91(9)
4
0.896
2
1.132
m (Mo Ka) (mmꢀ1
T (K)
Diffractometer
)
150(2)
Nonius KappaCCD area-detector
˚
Radiation, l (A)
Graphite-monochromated Mo Ka,
0.71073
44356
5060
Measured reflections
Independent reflections
Rint
45581
6179
0.042
0.151
Absorption correction
Min. transmission
Multi-scan
0.77
0.60

C.L. Foster et al. / Polyhedron 21 (2002) 1031ꢁ
/1041
1041
Table 8 (Continued)
[Cu(OH2)2(L1Ph)](BF4)2 (4)
[CuCl(HOMe)(L1Me2)]BF4 (7)
Max. transmission
Observed reflections
[I ꢀ2s(I)]
0.81
5257
0.82
4591
Range in 2u (8)
Range in h
Range in k
4.452u 555.0
ꢀ235h 523
ꢀ115k 511
ꢀ205l 521
467/30
3.852u 555.1
ꢀ135h 513
ꢀ145k 514
ꢀ155l 515
301/30
Range in l
Parameters/restraints
R(F) a, wR(F2)
Goodness-of-fit
Weighting scheme
b
0.037, 0.099
1.024
0.068, 0.170
1.069
wꢂ1/[s2(Fo2)ꢃ(0.0746P)2ꢃ1.1726P]
c
wꢂ1/
[s2(Fo2)ꢃ(0.0517P)2ꢃ1.6824P]
0.44/ꢀ0.60
ꢀ3
˚
Dr(max/min) (e A
Flack parameter
)
0.80/ꢀ0.85
a
Rꢂa[jFojꢀjFcj]/ajFoj.
b
c
4 1/2
] .
wRꢂ[aw(Fo2ꢀFc2)/awFo
Pꢂ(Fo2ꢃ2Fc2)/3.
[15] D.A. Evans, M.C. Kozlowski, J.A. Murry, C.S. Burgey, K.R.
Campos, B.T. Connell, R.J. Staples, J. Am. Chem. Soc. 121
(1999) 669.
Acknowledgements
The authors thank the Royal Society for a research
fellowship to M.A.H., the EPSRC for a studentship to
C.L.F., and the University of Leeds.
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