Large-ring chain and sheet polymeric metal complexes of extended-reach siloxypyridine ligands of type O[iPr2SiO(CH2)npy]2

Article abstract of DOI:10.1016/S0020-1693(02)01207-0

The preparations are reported of a range of metal complexes of Mn(II), Co(II), Ni(II) and Zn(II) with the 'extended reach' ligands O[ⁱPr₂SiO(CH₂)_npy]₂ (n=0, 1 or 3, I-III) and with Cu(II), Cd(II) and Ag(I) for II; six of them have been shown by X-ray studies to have polymeric structures. The compounds M[O(ⁱPr₂SiOpy)₂]₂Cl₂ (M=Co, Cu) form chains of 24-membered macrocycles, as does Co[O(ⁱPr₂SiOCH₂py)₂] ₂I₂(H₂O)₂. A similar structure is formed by Mn[O(ⁱPr₂SiOCH₂py)₂] ₂Cl₂ but in this case the rings are 28-membered. The complex Cu[O(ⁱPr₂SiOpy)₂]Cl₂ forms sheets of 52-membered macrocycles with chloride bridged Cu₂Cl₄ units at the node points. The structure of Cu₂[O(ⁱPr₂SiOpy)₂]₄Cl ₃ comprises sheets of 48-membered rings which are linked into pairs of sheets by linear, but weak, Cu-Cl-Cu bridges. X- and Q-band EPR spectra of the manganese compounds are also reported, as are relevant spectroscopic results for the other complexes.

Full text of DOI:10.1016/S0020-1693(02)01207-0

Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
www.elsevier.com/locate/ica
Large-ring chain and sheet polymeric metal complexes of extended-
reach siloxypyridine ligands of type O[iPr2SiO(CH2)npy]2
David M.L. Goodgame *, Paul D. Lickiss, Stephanie J. Rooke, Andrew J.P. White,
David J. Williams
Department of Chemistry, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK
Received 13 March 2002; accepted 12 July 2002
Abstract
The preparations are reported of a range of metal complexes of Mn(II), Co(II), Ni(II) and Zn(II) with the ‘extended reach’ ligands
O[iPr2SiO(CH2)npy]2 (nꢀ
/
0, 1 or 3, Iꢁ
/
III) and with Cu(II), Cd(II) and Ag(I) for II; six of them have been shown by X-ray studies to
Co, Cu) form chains of 24-membered macrocycles, as does
have polymeric structures. The compounds M[O(iPr2SiOpy)2]2Cl2 (Mꢀ
/
Co[O(iPr2SiOCH2py)2]2I2(H2O)2. A similar structure is formed by Mn[O(iPr2SiOCH2py)2]2Cl2 but in this case the rings are 28-
membered. The complex Cu[O(iPr2SiOpy)2]Cl2 forms sheets of 52-membered macrocycles with chloride bridged Cu2Cl4 units at the
node points. The structure of Cu2[O(iPr2SiOpy)2]4Cl3 comprises sheets of 48-membered rings which are linked into pairs of sheets by
linear, but weak, CuÃ
/
ClÃ/Cu bridges. X- and Q-band EPR spectra of the manganese compounds are also reported, as are relevant
spectroscopic results for the other complexes.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Crystal structures; Metal complexes; Polymeric complexes; Siloxanes
1. Introduction
of X-ray structural and spectroscopic studies on some of
the other compounds obtained.
We have recently demonstrated that the interaction of
the extended-reach ligands O[iPr2SiO(CH2)npy]2, where
nꢀ
/
0, 1 or 3 (IꢁIII) with a range of copper salts produces
/
a variety of metal coordination polymers [1]. Ligands of
that general type combine two attractive features for
polymer formation: (i) the siloxane linkage which
provides a high degree of flexibility in the bridging
capability of such ligands because of the very low barrier
(approximately 1ꢁ
/
2 kJ molꢂ1) to linearisation of the SiÃ
/
2. Results and discussion
OÃSi unit [2]; and (ii) the presence of the pyridyl donor
/
end-groups, which are well-established metal-binding
units, either when directly connected as in 4,4?-bipyridyl
Although we have studied the reactions of ligands IꢁIII
/
with a wide range of metal salts, our main aim in this work
was to investigate the ability of these extended reach
siloxypyridine ligands to generate polymeric compounds.
Accordingly, we concentrated on attempting to isolate
crystalline materials suitable for full characterisation by
single-crystal X-ray diffraction methods and we shall
discuss those results first. Where that definitive structural
information could not be achieved, more limited data
about the immediate coordination environment of the
metal ions were obtained by spectroscopic methods.
or when separated by organic spacers [3ꢁ12].
/
Our previous report was limited to results for selected
copper compounds because of the specific topic cover-
age of that special issue of this journal. We have,
however, explored the reactions of Iꢁ
/
III with a much
wider range of metal ions and we report here the results
* Corresponding author. Tel.: ꢃ
5804
E-mail address: d.goodgame@ic.ac.uk (D.M.L. Goodgame).
/
44-20-7594 5758; fax: ꢃ44-20-7594
/
0020-1693/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 0 - 1 6 9 3 ( 0 2 ) 0 1 2 0 7 - 0

62
D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
Fig. 2. Part of one of the polymer chains in the structure of 1.
plane. The OÃ
/
Siꢀ ꢀ ꢀSiÃ
/
O unit has a pseudo-gauche
geometry (778) and the SiÃ
/
OÃSi angle, 168.82(12)8, is
/
larger than was observed in Cu[O(iPr2SiOpy)2]2Br2. The
polymer chain (Fig. 2) propagates along the crystal-
¯
lographic 110 direction, the separation between adjacent
˚
in-chain cobalt atoms being 10.92 A. At the centre of
each 24-membered macrocycle there is a small void of
˚
approximately 2.5 A which could potentially accommo-
date small anions such as fluoride. There are no major
inter-chain interactions; in one direction the clorine
atoms in one chain are positioned toward the macro-
cycle ring centre in the next, whereas in the other the di-
isopropyl groups of neighbouring chains abut each
other at van der Waals distances.
Fig. 1. One of the 24-membered macrocycles in the polymeric
structure of 1 showing the octahedral cobalt environment and the
pseudo-gauche geometry of the silyl linkage.
Table 1
˚
Selected bond lengths (A) and angles (8) for 1
Bond lengths
CoÃ
CoÃ
CoÃ
/
Cl
2.448(2)
2.260(3)
2.237(3)
CoÃ
CoÃ
CoÃ
/
ClA
2.448(2)
2.260(3)
2.237(3)
/N(1)
/N(1A)
/N(14A)
/N(14B)
2.2. Structure of Mn[O(iPr2SiOCH2py)2]2Cl2 (2)
Bond angles
ClÃ
ClÃ
ClÃ
ClAÃ
ClAÃ
N(1)Ã
N(1A)Ã
N(14A)Ã
/
CoÃ
CoÃ
CoÃ
/
ClA
180.0
ClÃ
/
CoÃ
CoÃ
90.37(8) ClAÃ
90.63(8) ClAÃ
89.63(8) N(1)Ã
86.31(9) N(1)Ã
93.69(9) N(1A)Ã
N(14B) 180.0 O(9)Ã
Si(10)Ã
/
N(1)
90.63(8)
89.63(8)
89.37(8)
90.37(8)
180.0
The solid-state structure of Mn[O(iPr2SiOCH2-
py)2]2Cl2 (2) has, despite the presence of the extra two
methylene spacers in ligand II, a polymer structure very
similar to that of compound 1. Surprisingly, although
the silyl ligand length has been increased, the separation
˚
between adjacent metal centres is reduced (10.00 A, cf.
˚
10.92 A in 1) (Fig. 3). The distortions from ideal
octahedral coordination geometry at the metal are again
/
/N(1A)
89.37(8) ClÃ
/
/
N(14A)
/
/N(14B)
/
CoÃ
CoÃ
CoÃ
CoÃ
/
N(1)
/
CoÃ
CoÃ
CoÃ
CoÃ
CoÃ
/N(1A)
/
/
N(14A)
/
/N(14B)
/
/
N(1A)
/
/N(14A)
/
/
N(14B)
93.69(9)
86.31(9)
168.82(12)
/
/
N(14A)
/
CoÃ
/N(14B)
/
/
/
/Si(8)
2.1. Structure of Co[O(iPr2SiOpy)2]2Cl2 (1)
small, with cis-angles in the range 84.69(9)ꢁ
(Table 2). The MnÃN and MnÃCl distances [MnÃ
2.330(3) and 2.370(3) A, MnÃ
/
95.31(7)8
/
/
/N
The X-ray analysis of Co[O(iPr2SiOpy)2]2Cl2 (1)
shows that it has a chain polymer structure similar to
that observed previously for the copper(II) bromide
analogue [1]. The geometry at each cobalt atom, which
is positioned on a crystallographic inversion centre, is
slightly distorted octahedral (Fig. 1) with cis-angles in
˚
˚
/
Cl 2.4687(9) A] are
unexceptional. The small distortions from strict octahe-
dral geometry at the manganese centres do, however,
lead to pronounced zero-field splittings (zfs) and com-
plex EPR spectra, as discussed subsequently.
The pyridyl rings are inclined by 66 and 708 to the
equatorial MnN4 coordination plane, tilt angles slightly
the range 86.31(9)ꢁ
pendent CoÃN distances of 2.237(3) and 2.260(3) A
differ, though the difference here is not as large as
observed for the CuÃ
N distances in Cu[O(iPr2SiO-
py)2]2Br2. Comparable differences in the CoÃN dis-
tances have been observed previously [13,14] for other
compounds of the type CoL4Cl2 containing pyridyl
donor groups and, indeed, quite large variations in
/
93.69(9)8 (Table 1). The two inde-
˚
/
smaller than those in 1. Within the disilyl-unit the OÃ
Siꢀ ꢀ ꢀSiÃO torsional relationship is again pseudo gauche
(328) but with a more flattened geometry. The SiÃOÃSi
/
/
/
/
/
/
angle, 173.6(2)8, is more nearly linear than in 1. The
small void in the centre of the macrocycle in 1 is not
present in 2 as the N(1)-containing pyridyl rings have
edgeꢁ
/
edge protonꢁproton overlap and an inter-planar
/
˚
separation of only approximately 2.6 A.
both CoÃ
type of complex [13ꢁ
steeply inclined, by approximately 748, to the CoN4
/
N and CoÃ
/
Cl bond lengths are known for this
/
16]. The pyridyl rings in 1 are
In 2 the polymer chain propagates along the crystal-
lographic b direction with the manganese atoms being

D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ
/
73
63
Fig. 4. The pair of independent 28-membered macrocycles, A and B,
in the polymeric structure of 3, showing the octahedral geometry at the
cobalt centre and the axial aqua ligands.
Table 3
˚
Selected bond lengths (A) and angles (8) for 3
Fig. 3. One of the 28-membered macrocycles in the polymeric
structure of 2 showing the octahedral manganese environment and
the pseudo-gauche geometry of the silyl linkage. The broken bonds
indicate the direction of the polymer chain propagation.
Bond lengths
CoÃ
CoÃ
CoÃ
/
O(1)
2.087(7) CoÃ
2.150(9) CoÃ
2.148(9) CoÃ
/
O(2)
2.107(7)
2.164(9)
2.141(9)
/N(1)
/N(16B)
/N(32)
/N(47A)
Table 2
Bond angles
˚
Selected bond lengths (A) and angles (8) for 2
O(1)Ã
O(1)Ã
O(1)Ã
O(2)Ã
O(2)Ã
N(1)Ã
N(16B)Ã
N(32)ÃCoÃ
Si(42)Ã
/
CoÃ
CoÃ
CoÃ
CoÃ
CoÃ
CoÃ
/
O(2)
178.7(4) O(1)Ã
88.3(3) O(1)Ã
92.1(4) O(2)Ã
87.4(4) O(2)Ã
89.1(4) N(1)Ã
176.0(3) N(1)Ã
91.2(3) N(16B)Ã
89.1(3) Si(9)ÃO(10)Ã
170.0(7)
/
CoÃ
CoÃ
CoÃ
CoÃ
CoÃ
CoÃ
/
N(1)
87.7(3)
91.4(4)
92.8(3)
91.1(3)
88.7(3)
91.2(3)
176.5(4)
170.6(7)
/
/N(32)
/
/N(16B)
Bond lengths
/
/
N(47A)
N(16B)
N(47A)
/
/N(1)
MnÃ
MnÃ
MnÃ
/
Cl
N(1)
N(16A)
2.4687(9) MnÃ
/
ClB
N(1B)
N(16B)
2.4687(9)
2.370(3)
2.330(3)
/
/
/
/N(32)
/
2.370(3)
2.330(3)
MnÃ
MnÃ
/
/
/
/
/
N(16B)
N(47A)
/
/
/
/
N(32)
/
/
Bond angles
/
CoÃ
/N(32)
/
CoÃ
/N(47A)
ClÃ
ClÃ
ClÃ
ClBÃ
ClBÃ
N(1)Ã
N(1B)Ã
N(16A)Ã
/
MnÃ
MnÃ
MnÃ
/
ClB
180.0
ClÃ
/
MnÃ
MnÃ
89.07(7) ClBÃ
89.89(7) ClBÃ
90.93(7) N(1)Ã
84.69(9) N(1)Ã
95.31(9) N(1B)Ã
N(16B) 180.0 O(10)Ã
Si(9)Ã
/
N(1)
89.89(7)
90.93(7)
90.11(7)
89.07(7)
180.0
/
/
N(47A)
/
/Si(11)
/
/N(1B)
90.11(7) ClÃ
/
/N(16A)
/
O(41)ÃSi(40)
/
/
/N(16B)
/
MnÃ
MnÃ
MnÃ
MnÃ
/
N(1)
/
MnÃ
/
N(1B)
/
/
N(16A)
/
MnÃ
/
N(16B)
/
/N(1B)
Co[O(iPr2SiOCH2py)2]2I2(H2O)2, and to differ from
the manganese(II) chloride complex, 2, in having a
pair of aqua ligands coordinated axially to the cobalt
centre in place of halide ions (Fig. 4). The structure is
again polymeric but has two unique O(iPr2SiOCH2py)2
ligands and hence two potentially different 28-mem-
bered rings, A and B. Whereas in 2 the Mn atom lies on
an inversion centre, here in 3 the inversion centres are at
the centres of the macrocycles. The cobalt atom lies in a
general position and the Co(py)4(OH2)2 unit has pseudo
D4 propeller symmetry; the pyridyl rings are inclined by
/
MnÃ
MnÃ
MnÃ
/N(16A)
/
/N(16B)
95.31(9)
84.69(9)
173.6(2)
/
/
N(16A)
/
MnÃ
/
N(16B)
Si(11)
/
/
/
/
positioned on adjacent unit cell origins. Neighbouring,
partially overlapping polymer chains are cross-linked by
a weak parallel stacking of the N(16)-containing pyridyl
rings (centroidꢀ ꢀ ꢀcentroid and mean inter-planar separa-
˚
tions of 3.89 and 3.84 A, respectively) and by an edge-
to-face CÃ
/
Hꢀ ꢀ ꢀp interaction between C(19)Ã
/
H in one
chain and the N(1)-containing pyridyl ring of the next
˚
(Hꢀ ꢀ ꢀp 2.70 A, CÃHꢀ ꢀ ꢀp 1528). These offset stacked
/
between 43 and 508 to the CoN4 plane. The CoÃ
CoÃO distances, which are in the ranges 2.141(9)ꢁ
2.164(9) and 2.087(7)ꢁ
3), are unexceptional.
/N and
polymer chains are bounded on the other side by
i
/
/
SiÃ
/
iPrꢀ ꢀ ꢀ PrÃ
/
Si van der Waals contacts.
˚
2.107(7) A, respectively (Table
/
2.3. Structure of Co[O(iPr2SiOCH2py)2]2I2(H2O)2
(3)
Analysis of the conformations of the two independent
silyl ligands shows them to have virtually identical
˚
geometries with an rms deviation of only 0.15 A of
their best fit. Indeed the two macrocycles, A and B, have
virtually identical conformations with an rms deviation
The crystalline sample of the cobalt(II) iodide com-
plex obtained by the layering technique was found by
single crystal X-ray analysis to have the formula
˚
of approximately 0.14 A. The OÃ
/
Siꢀ ꢀ ꢀSiÃ
/
O torsion

64
D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
Table 4
˚
Selected bond lengths (A) and angles (8) for 4
Bond lengths
CuÃ
CuÃ
CuÃ
/
Cl
2.3240(14) CuÃ
/
ClA
2.3240(14)
2.038(5)
2.643(5)
/N(1)
2.038(5)
2.643(5)
CuÃ
CuÃ
/N(1B)
/N(14A)
/
N(14B)
Bond angles
ClÃ
ClÃ
ClÃ
ClAÃ
ClAÃ
N(1)Ã
N(1B)Ã
N(14A)Ã
/
CuÃ
CuÃ
CuÃ
/
ClA
180.0
ClÃ
/
CuÃ
CuÃ
91.21(11) ClAÃ
89.82(13) ClAÃ
88.79(11) N(1)Ã
/
N(1)
N(14A)
89.82(13)
88.79(11)
90.18(13)
91.21(11)
180.000(2)
88.9(2)
/
/N(1B)
90.18(13) ClÃ
/
/
/
/N(14B)
/
CuÃ
CuÃ
CuÃ
CuÃ
N(1B)Ã
Si(8)ÃO(9)Ã
/
N(1)
/
CuÃ
CuÃ
CuÃ
CuÃ
CuÃ
/N(1B)
/
/
N(14A)
/
/N(14B)
/
/
N(1B)
/
/
N(14A)
N(14A)
91.1(2)
N(1)Ã
/
/
N(14B)
/
/
88.9(2)
/
CuÃ
/N(14B)
91.1(2)
171.5(4)
/
/
N(14B) 180.0
/
/Si(10)
2.4. Structure of Cu[O(iPr2SiOpy)2]2Cl2×
/
2MeOH (4)
As summarised in Section 3, three different types of
crystals (denoted A, B, and C) were obtained from the
reaction between copper(II) chloride and ligand I in
methanol. All three have polymeric structures and that
with the simplest structure (the pale blue prisms, C) has
Fig. 5. The cross-linking of adjacent polymer chains in 3 by OÃ
/
Hꢀ ꢀ ꢀI
hydrogen bonds. The hydrogen bonding geometries are [Oꢀ ꢀ ꢀI], [Hꢀ ꢀ ꢀI]
˚
(A), [OÃ
/
Hꢀ ꢀ ꢀI] (8): (a) 3.46, 2.57, 173; (b) 3.45, 2.59, 160; (c) 3.51, 2.78,
139; (d) 3.52, 2.64, 164. The isopropyl groups have been omitted for
clarity.
stoichiometry Cu[O(iPr2SiOpy)2]2Cl2×
/2MeOH, and
forms a chain polymer directly analogous to that of 1,
with the metal atom positioned on an inversion centre.
Each macrocyclic unit comprises a 24-membered ring
(Fig. 6) with transannular Cuꢀ ꢀ ꢀCu separations of 9.00
˚
A and a gauche relationship for the terminal SiÃ
/
O
bonds (OÃ
/
Siꢀ ꢀ ꢀSiÃ
/
O 668) and with SiÃ
/
OÃSi 171.5(4)8
/
(Table 4). The pyridyl rings are inclined by 34 [N(1)] and
818 [N(14)] to the CuN4 plane. The flattened orientation
of the N(1)-containing pyridine rings coupled with the
inwardly directed silyl isopropyl groups result in self-
filling of the macrocyclic ring.
The CuÃ
/
N(1) and CuÃ
/
Cl distances, 2.038(5) and
2.324(1) A, respectively, are typical of those seen in,
for example, Cu(py)2Cl2 and related compounds [17ꢁ
19], whilst the CuÃN(14) distance is substantially longer
˚
/
/
˚
at 2.643(5) A. The metal environment can thus be
visualised as a planar CuN2Cl2 unit with a pair of
loosely bonded pyridyl nitrogen atoms occupying the
axial positions.
Fig. 6. One of the 24-membered macrocycles in the polymeric
structure of 4 showing the copper environment and the pseudo-gauche
geometry of the silyl linkage. The broken bonds indicate the direction
of the polymer chain propagation.
The packing of the chains is similar to that observed
for 1, with no short inter-chain contacts of note. The
included methanol molecules are disordered and located
in voids between the chains.
angles are 80 and 838, a geometry much closer to
orthogonal than was seen in 2; the SiÃ
/
OÃ
/
Si angles are
2.5. Structure of Cu[O(iPr2SiOpy)2]Cl2 (5)
very similar at approximately 1708. The transannular
˚
Coꢀ ꢀ ꢀCo separation is 11.49 A.
The polymer chains propagate in the crystallographic
c direction and have the isopropyl groups of adjacent
chains in the b direction in van der Waals contact. In the
crystallographic a direction adjacent chains are cross-
linked via hydrogen bonds between the aqua ligands and
the non-coordinated iodide anions (Fig. 5).
Crystals of type B were found by crystallographic
analysis to have the stoichiometry Cu[O(iPr2SiOpy)2]Cl2
and to contain enlarged (52-membered) macrocycles
with five-coordinate copper centres and four O(iPr2-
SiOpy)2 ligands (Fig. 7). Within each macrocycle there
are two bridging Cu2Cl4 units. The geometry at each

D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ
/
73
65
Table 5
˚
Selected bond lengths (A) and angles (8) for 5
Bond lengths
CuÃ
CuÃ
CuÃ
/
Cl(1)
2.3389(12) CuÃ
/
Cl(1A)
2.6354(13)
2.019(3)
/Cl(2)
2.2633(12) CuÃ
/
N(1)
/N(14E)
2.007(3)
Bond angles
Cl(1)Ã
Cl(1)Ã
Cl(1A)Ã
Cl(1A)Ã
N(14E)Ã
CuÃCl(1)Ã
/
CuÃ
/
Cl(2)
168.71(5)
Cl(1)Ã
/
CuÃ
CuÃ
96.97(10) Cl(1A)Ã
96.61(10) N(1)ÃCuÃ
90.42(10) N(14E)ÃCuÃ
87.64(4) O(9)ÃSi(10)
Si(8)Ã
/
Cl(1A)
92.36(4)
88.06(10)
98.93(5)
91.24(10)
165.9(2)
165.3(2)
/
CuÃ
/N(1)
87.58(11) Cl(1)Ã
/
/N(14E)
/
CuÃ
CuÃ
CuÃ
CuA
/N(1)
/
CuÃ
Cl(2)
N(1)
/Cl(2)
/
/N(14E)
/
/
/
/Cl(2)
/
/
/
/
/
/
Fig. 7. One of the 52-membered macrocycles in the structure of 5
showing the five-coordinate Cu centres and the Cu2Cl2 linkages.
Across the Cu2Cl2 bridge adjacent pyridyl rings are in a p-
stacking relationship with a mean interplanar separation
˚
centroid distance
of 3.51 A and a ringÃ
/
centroidꢀ ꢀ ꢀringÃ
/
copper centre is square pyramidal, the basal plane
comprising the two unique nitrogen atoms, N(1) and
˚
N(14), at 2.019(3) and 2.007(3) A, respectively, and two
Clorine atoms, Cl(1) and Cl(2), at 2.339(1) and 2.263(1)
˚
A, respectively. The apical axial site is occupied by Cl(1)
from a symmetry-related copper coordination sphere at
˚
of 4.02 A; the rings are mutually inclined by 118. The
inwardly directed isopropyl groups fill the central ring
cavity. In contrast to the chain polymer described for C,
here a sheet polymer results (Fig. 8) and adjacent sheets
pack simply with only van der Waals contacts.
˚
a characteristically lengthened distance of 2.635(1) A.
2.6. Structure of Cu2[O(iPr2SiOpy)2]4Cl3 (6)
The copperꢀ ꢀ ꢀcopper separation within this dinuclear
˚
unit is 3.45 A.
The di-isopropylsilyl units have a distinctly extended
geometry very different from that in the structures
The third crystalline product, A, from the reaction of
copper(II) chloride with ligand I in methanol was found
by single crystal X-ray analysis to have the unexpected
stoichiometry Cu2[O(iPr2SiOpy)2]4Cl3 and the most
complex structure of the three products. As in B the
structure contains macrocycles comprising four O(iPr2-
described above, having an OÃ
/
Siꢀ ꢀ ꢀSiÃ
/
O torsion angle
of 1298; the SiÃ
/
OÃ
/
Si angle is 165.3(2)8.
Within the larger macrocycle the transannular
˚
Cuꢀ ꢀ ꢀCu separations range between 13.7 and 22.3 A.
Table 6
˚
Selected bond lengths (A) and angles (8) for 6
Bond lengths
Cu(1)Ã
Cu(1)Ã
Cu(1)Ã
Cu(2)Ã
Cu(2)Ã
Cu(2)Ã
/
Cl(1)
2.650(2)
2.046(4)
2.046(4)
2.707(3)
2.034(4)
2.034(4)
Cu(1)Ã
Cu(1)Ã
Cu(1)Ã
Cu(2)Ã
Cu(2)Ã
Cu(2)Ã
/
Cl(3)
2.796(2)
2.046(4)
2.046(4)
2.855(3)
2.034(4)
2.034(4)
/N(1)
/
N(1A)
N(1E)
Cl(3B)
N(14B)
N(14E)
/N(1D)
/
/Cl(2)
/
/N(14)
/
/N(14D)
/
Bond angles
Cl(1)ÃCu(1)Ã
Cl(1)ÃCu(1)Ã
Cl(1)ÃCu(1)Ã
Cl(3)ÃCu(1)Ã
Cl(3)ÃCu(1)Ã
N(1)ÃCu(1)Ã
N(1A)ÃCu(1)Ã
N(1D)ÃCu(1)Ã
Cl(2)ÃCu(2)ÃN(14)
Cl(2)ÃCu(2)ÃN(14B)
Cl(3B)ÃCu(2)Ã
Cl(3B)ÃCu(2)Ã
N(14)ÃCu(2)Ã
N(14)ÃCu(2)Ã
N(14B)Ã
Si(10)ÃO(9)Ã
/
/
Cl(3)
180.0
Cl(1)Ã
Cl(1)Ã
Cl(3)Ã
Cl(3)Ã
N(1)ÃCu(1)Ã
N(1)ÃCu(1)Ã
N(1A)Ã
Cl(2)ÃCu(2)Ã
Cl(2)ÃCu(2)Ã
Cl(2)ÃCu(2)Ã
Cl(3B)ÃCu(2)Ã
Cl(3B)ÃCu(2)Ã
N(14)ÃCu(2)Ã
N(14B)ÃCu(2)Ã
N(14D)ÃCu(2)Ã
/
Cu(1)Ã
Cu(1)Ã
Cu(1)Ã
Cu(1)Ã
/
N(1)
90.97(11)
90.97(11)
89.03(11)
89.03(11)
89.984(4)
89.984(4)
178.1(2)
/
/
N(1A)
N(1E)
N(1A)
N(1E)
90.97(11)
90.97(11)
89.03(11)
89.03(11)
178.1(2)
89.984(4)
89.984(4)
90.98(12)
90.98(12)
89.02(12)
89.02(12)
89.983(5)
89.983(5)
178.0(2)
164.5(3)
/
/
N(1D)
N(1)
/
/
/
/
/
/
/
/
N(1D)
/
/
/
/
N(1A)
/
/
N(1D)
N(1D)
N(1E)
/
/N(1E)
/
/
/
Cu(1)ÃN(1E)
/
/
/
/
/
Cl(3B)
N(14D)
N(14E)
180.0
/
/
/
/
90.98(12)
90.98(12)
89.02(12)
89.02(12)
178.0(2)
/
/
/
/
/
/
N(14)
/
/N(14B)
/
/
N(14D)
/
/N(14E)
/
/N(14B)
/
/
N(14D)
N(14D)
N(14E)
/
/N(14E)
/
/
89.983(5)
89.983(5)
/
Cu(2)Ã
/N(14E)
/
/
/
/
Si(8)

66
D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
Fig. 8. Part of one of the two-dimensional polymer sheets in the
structure of 5. The isopropyl groups have been omitted for clarity.
Fig. 10. One of the two-dimensional sheets of linked macrocycles of 6.
The isopropyl groups have been omitted for clarity.
imidazole derivatives in which the CuÃ
/Cl distances
˚
range between 2.8 and 3.0 A [20ꢁ22].
/
Both independent Cu(py)4 units are positioned on
crystallographic C4 axes and adopt propeller conforma-
tions with the N(1)-containing pyridyl rings inclined by
518 to the CuN4 plane and the N(14)-containing rings by
578. The di-isopropylsilyl unit has a gauche geometry with
OÃ
/
Siꢀ ꢀ ꢀSiÃ
/
O 578 and SiÃ
/
OÃSi 164.6(3)8. The inwardly
/
directed isopropyl groups fill the macrocycle cavity.
Adjacent macrocycles are linked in the Cu(py)4 plane
to form a sheet polymer (Fig. 10) which is linked face-to-
face to its nearest neighbour by the chloride ion Cl(3)
(Fig. 11). The CuÃ
/
Cl distances involving the bridging
˚
anions are the longest at 2.796(2) and 2.855(3) A, to
Cu(1) and Cu(2), respectively.
Fig. 9. One of the 48-membered macrocycles in the structure of 6
showing the two independent copper environments.
The structure has, additionally, three included metha-
nolmoleculesperCucentreandthesearedistributedinthe
regions between the linked face-to-face sheets and the
isopropyl bounded back-to-back arrangements. The
SiOpy)2 ligands, though here they simply link adjacent
but crystallographically independent copper centres to
create 48-membered rings (Fig. 9). The transannular
unexpected 2:3 CuꢁCl ratio suggests a charge imbalance
/
˚
Cuꢀ ꢀ ꢀCu distances are 18.0 A.
but this is probably compensated for by some of the
included methanol molecule sites actually being occupied
by a requisite number of methoxide anions. An alternative
explanation that the complex contains equal proportions
of Cu(II) and Cu(I) is not supported by the geometries
observed for each copper coordination sphere.
The geometry at each Cu centre can best be described
as a planar CuN4 unit with CuÃ
/
N distances of between
2.034(4) and 2.045(4) A. Two chloride ions approach
˚
this unit axially but at distances that are substantially
˚
longer [2.650(3)ꢁ2.855(3) A] than in the preceding
/
structures. This geometry sees a reversal of the roles of
one of the pyridyl rings and chloride ions relative to that
adopted in compound 4, which had two long CuÃ
/
N
2.7. Spectroscopic studies
bonds axial to a CuN2Cl2 plane. So far as we are aware,
there are no other structurally characterised examples of
Cu(py)4Cl2 arrangements of this type, though there are
comparable geometries for monomeric complexes with
Although full X-ray characterisation was obtained
only for the six compounds discussed above, measure-
ments of the solid-state electronic spectra (Table 7) of

D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ
/
73
67
Fig. 11. The weak covalent face-to-face linking of adjacent sheets of 6 by the loosely bound, axial Cl(3) ligand.
n(MnÃ
/
Cl) bands for Mn[O(iPr2SiO(CH2)3py)2]Cl2 and
Cl, Br) bands for the complexes
n(ZnÃX) (Xꢀ
/
/
Zn[O(iPr2SiOCH2py)2]X2 and Zn[O(iPr2SiO(CH2)3-
py)2]X2 are also consistent with tetrahedral coordination
geometry in those complexes, though their long-range
polymer structures are unknown.
The EPR spectra of the six-coordinate manganese(II),
high-spin d5, complexes, measured on powdered samples,
reveal the differing extents of the distortions from
idealised octahedral geometry. Whereas a high-spin
Mn(II) ion in a strictly Oh symmetry coordination
environment should give (neglecting the effects of nuclear
hyperfine interactions) a single EPR band at gꢀ2, more
/
complex spectra result as the coordination symmetry is
lowered [25]. This zfs is conventionally expressed in the
spin Hamiltonian in terms of the parameters D, a measure
of the axial distortion from cubic symmetry, and E, the
measure of rhombic distortion. The parameter l (ꢀ
/E/D)
is often used in place of E.
Despite the polymeric nature of the complexes
reported here, the lengths of the siloxypyridine bridges
and the transannular metalꢀ ꢀ ꢀmetal distances are too
great to cause any significant magnetic concentration
between the metal centres, so their EPR spectra show
the effects of zfs generally similar to those observed for
simple, monomeric manganese(II) complexes MnL4X2
where L is a unidentate N-heterocycle such as 4-
methylpyridine [26].
The simplest spectra are those of Mn[O(iPr2SiOCH2-
py)2]2(NCS)2 and Mn[O(iPr2SiO(CH2)3py)2]2(NCS)2
(Fig. 12). Although we have no X-ray analysis available
to confirm the long-range structure of Mn[O(iPr2-
SiOCH2py)2]2(NCS)2 its EPR spectrum (A in Fig. 12)
indicates the presence of a slightly distorted trans-
octahedral MnN6 coordination geometry at each Mn
Fig. 12. X-band EPR spectra at room temperature of powdered solid
samples of: (A) Mn[O(iPr2SiOCH2py)2]2(NCS)2; (B) Mn[O(iPr2-
SiO(CH2)3py)2]2(NCS)2.
the cobalt(II) and nickel(II) complexes reported in
Section 3 show that nearly all of them have the
stoichiometry ML2X2 and have the low intensity dꢁd
/
spectra characteristic of six-coordinate coordination
geometry at the metal centres and they therefore most
probably long-range structures analogous to those of
compounds 1 and 2. Exceptions to this are the blue 1:1
complexes Co[O(iPr2SiOCH2py)2]Br2, and Co[O(iPr2-
SiO(CH2)3py)2]X2 (XꢀCl, Br), the electronic spectra
/
of which are typical of tetrahedral CoN2X2 chromo-
phores [23]. Additional evidence for tetrahedral geome-
try at the cobalt centres in these compounds is provided
by the positions of the n(CoÃ
/
X) bands in their low-
frequency infrared spectra (listed in Section 3) [24]. The
centre, as it comprises a strong band at gꢀ
/
2 with weak
‘wings’ to both higher and lower fields consistent with a

68
D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
Table 7
Solid-state electronic spectra for some cobalt(II) and nickel(II) complexes of IꢁIII
/
Compound
Colour
Band energies (cmꢂ1
)
Co[O(iPr2SiOpy)2]2Cl2
violet
violet
7700br, 15,400sh, 18,200
7600br, 19,200br
Co[O(iPr2SiOpy)2]2Br2
Ni[O(iPr2SiOpy)2]2Cl2
Ni[O(iPr2SiOpy)2]2Br2
turquoise
turquoise
turquoise
lilac
8700, 10,700sh, 16,000, 25,000
8000, 15,900, 25,000
Ni[O(iPr2SiOpy)2]2(NO3)2
Ni[O(iPr2SiOpy)2]2(NCS)2
Co[O(iPr2SiOCH2py)2]2Cl2
Co[O(iPr2SiOCH2py)2]Br2
Co[O(iPr2SiOCH2py)2]2(NO3)2
Co[O(iPr2SiOCH2py)2]2(NCS)2
Ni[O(iPr2SiOCH2py)2]2Cl2
10,000, 17,000, 26,300
10,750, 17,400, 26,600
8000, 19,600br
pink
blue
6050sh, 7400, 9800, 16,900
9600, 21,000
9700, 20,000br
orange
pink
turquoise
pale blue
pale blue
blue
9100, 11,100sh, 16,100, 25,250
10,500br, 17,500, 26,700
11,100, 17,600, 27,000
6150sh, 7250, 10,000, 16,800
6060sh, 7140, 9760, 16,200
9900, 15,400sh, 20,400br
Ni[O(iPr2SiOCH2py)2]2(NO3)2×
Ni[O(iPr2SiOCH2py)2]2(NCS)2
Co[O(iPr2SiO(CH2)3py)2]Cl2
Co[O(iPr2SiO(CH2)3py)2]Br2
/(H2O)2
blue
peach
Co[O(iPr2SiO(CH2)2py)2]2(NCS)2
very small D value, comparable to that (0.035 cmꢂ1
)
ordination sphere to MnN4Cl2. Good simulation of the
spectrum was achieved with an isotropic g value of 2.00
observed for Mn(4-methylpyridine)4(NCS)2 [26]. It
seems likely that the structure of Mn[O(iPr2SiOCH2-
py)2]2(NCS)2 is analogous to that of 2 but with N-
bonded, isothiocyanate, anions replacing chlorides in
the axial positions. The EPR spectrum of Mn[O(iPr2-
SiO(CH2)3py)2]2(NCS)2 (B in Fig. 12) is of the same type
but with slightly greater distortion of the primary MnN6
coordination sphere and a consequent increase in zfs.
In contrast to the relatively simple spectra of the
isothiocyanates the room temperature EPR spectra of 2
at X- and Q-band frequencies (Figs. 13 and 14,
respectively) are more complex because of the increased
zfs arising from the change from a trans-MnN6 co-
and with Dꢀ
/
0.195 cmꢂ1 and lꢀ
0.063, values compar-
/
able to those found in early work on simple monomeric
complexes such as Mn(4-methylpyridine)4Cl2 [26]. The
small l value reflects the minor rhombic geometric
distortions from Oh symmetry at the Mn centre shown
by the X-ray study.
X- and Q-band spectra were also obtained for
Mn[O(iPr2SiOpy)2]2Br2 (Figs. 13 and 14). The replace-
ment of chloride by bromide in the axial positions of the
coordination sphere would be expected to increase the
zfs, resulting in a decrease in the number of observed
transitions and the presence of the dominant band in the
X-band spectrum in the geff
That is the case for Mn[O(iPr2SiOpy)2]2Br2 and the
observed resonance positions suggest a D value of
ꢀ6 region in low field [26].
/
Fig. 13. X-band EPR spectra at room temperature of powdered solid
samples of: (A) Mn[O(iPr2SiOCH2py)2]2Cl2; (B) Mn[O(iPr2SiO-
py)2]2Br2.
Fig. 14. Q-band EPR spectra at room temperature of powdered solid
samples of: (A) Mn[O(iPr2SiOCH2py)2]2Cl2; (B) Mn[O(iPr2SiO-
py)2]2Br2.

D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ
/
73
69
approximately 0.7 cmꢂ1, a value that, again, is in good
agreement with simpler, monomeric MnN4Br2 com-
pounds [26].
The other metal salts used were standard commercial
reagents.
Spectra obtained at low temperatures (107 K for X-
band and 120 K for Q-band) for the chloride and the
bromide are virtually identical to those at room
temperature confirming that there are no significant
structural changes on cooling to those temperatures.
In contrast to the above, the EPR spectra of the solid
copper complexes are relatively uninformative. The
spectra of compounds 4 and 6 each showed a single
3.1.3. Metal complexes
The metal complexes were obtained either by simply
mixing solutions of the respective reagents in organic
solvents or, in attempts to obtain X-ray quality crystals,
by a solvent ‘layering’ technique. In this latter approach
a solution of the siloxypyridine ligand in MeCN or
EtOH was placed in a small test-tube. To this was
carefully added ‘buffer’ layers of solute-free solvent(s)
followed by a solution of the metal salt in MeOH, EtOH
or MeCN. The tube was then stored at room tempera-
ture (r.t.) until the product either formed crystals of
sufficient quality for X-ray analysis or gave a micro-
crystalline powder. Products of insufficient quality for
X-ray study were dried at approximately 60 8C, and
subjected to routine elemental analysis followed, where
possible, by characterisation by other physical methods.
Specific details, or differences from the above general
method, are given below.
broad band (at gꢀ
whereas compound 5 had an axial-type spectrum (gꢀ
2.065 and 2.256). The spectrum of Cu2[O(iPr2SiOCH2-
py)2](C3H7CO2)4 is of the standard Sꢀ1 type seen for
/
2.066 and 2.065, respectively)
/
/
dinuclear copper(II) alkanoates [27] which suggests that
it comprises chains of such units linked by O(iPr2-
SiOCH2py)2 bridges.
2.8. Concluding comments
Whilst the structural studies described here, and those
reported earlier [1], show that the siloxypyridine ligands
3.1.4. Complexes of ligand I
IꢁIII, and others of that same type, will be fruitful
/
sources of large ring polymers with a range of transition
metal ions, it is clear that there are limitations in their
use for the formation of robust zeotype materials. One
limiting factor is the steric requirement of the pyridine
unit as the donor group as that considerably lessens the
chances of forming three-dimensional networks invol-
ving M(pyridine)6 node points; this limiting factor is
present, of course, in the many other types of extended
reach pyridine derivatives that have received extensive
study in recent years. The structural results, and
particularly those for the copper chloride complexes,
also reveal the difficulties in achieving a good measure
of predictive capability of the long-range structures
because of the conformational flexibility of these
disiloxypyridne ligands.
3.1.4.1. Mn[O(iPr2SiOpy)2]2Cl2. Layering a solution
of MnCl2×
/
4H2O (0.01 g) in EtOH (0.5 cm3) and I (0.043
g) in MeCN (0.5 cm3) and a few drops of CHCl3 gave a
white microcrystalline solid after 30 min. Yield: 71%,
m.p. 170ꢁ171 8C. Anal. Calc. for C44H72Cl2Mn-
/
N4O6Si4: C, 53.4; H, 7.3; N, 5.7. Found: C, 53.4; H,
7.9; N, 5.5%.
3.1.4.2. Mn[O(iPr2SiOpy)2]2Br2. This was obtained as
colourless needles, in 39% yield, as for the previous
compound but using MnBr2×
/
4H2O (0.014g) in MeOH (1
212 8C.
Anal. Calc. for C44H72Br2MnN4O6Si4: C, 49.0; H, 6.7;
cm3), and after a period of 10 days. M.p. 211ꢁ
/
N, 5.2. Found: C, 49.5; H, 7.0; N, 5.2%.
3.1.4.3. Co[O(iPr2SiOpy)2]2Cl2. Violet crystals suita-
ble for X-ray characterisation were obtained in 74%
3. Experimental
yield after 24 h by the layering method using CoCl2×
/
6H2O (0.012 g) in EtOH (1 cm3) and I (0.043 g) in
MeCN (0.5 cm3). M.p. 131 8C. Anal. Calc. for
C44H72Cl2CoN4O6Si4: C, 53.2; H, 7.3; N, 5.6. Found:
C, 54.0; H, 7.5; N, 5.5%.
3.1. Preparations
3.1.1. Ligands IꢁIII
/
These were obtained as described previously [1].
3.1.4.4. Co[O(iPr2SiOpy)2]2Br2. This complex sepa-
rated as a violet solid, in 42% yield, over a period of 3
days from an isopropanol solution (7 cm3) containing I
3.1.2. Metal salts
Solutions of the metal thiocyanates were obtained by
mixing concentrated solutions of potassium thiocyanate
and the respective hydrated metal nitrate in hot EtOH in
2:1 mole ratio, cooling in the fridge overnight and
filtering off the precipitated KNO3. The metal thiocya-
nate complexes were obtained by using appropriate
aliquots from these stock solutions.
(0.043 g) and CoBr2×
/
6H2O (0.011 g). Anal. Calc. for
C44H72Br2CoN4O6Si4: C, 48.8; H, 6.7; N, 5.2. Found: C,
48.4; H, 6.2; N, 5.1%.
3.1.4.5. Ni[O(iPr2SiOpy)2]2Cl2. Addition of a solution
of NiCl2×
/
6H2O (0.059 g) in a mixture of MeCN (2 cm3)

70
D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
and MeOH (2 cm3) to neat I (0.215 g, 0.5 mmol)
afforded a dark green solution from which a turquoise
solid separated over 30 min. Yield: 66%, m.p. approxi-
3.1.5. Complexes of ligand II
3.1.5.1. Mn[O(iPr2SiOCH2py)2]2Cl2. Addition of
mately
205 8C
(dec.).
Anal.
Calc.
for
MnCl2×
/
4H2O (0.02 g) in EtOH (1 cm3) to a solution
C44H72Cl2N4NiO6Si4: C, 53.2; H, 7.3; N, 5.6. Found:
C, 52.8; H, 7.4; N, 5.6%.
of II (0.092 g) in isopropanol (1 cm3) gave, after 24 h,
colourless crystals suitable for X-ray studies. Yield:
77%, m.p. 143ꢁ144 8C. Anal. Calc. for C48H80Cl2-
MnN4O6Si4: C, 55.1; H, 7.7; N, 5.4. Found: C, 55.1;
H, 7.7; N, 5.1%.
/
3.1.4.6. Ni[O(iPr2SiOpy)2]2Br2. Layering I (0.043 g) in
MeCN (1 cm3) with a solution of NiBr2×
/
3H2O (0.014 g)
in MeOH (2 cm3) and a few drops of CHCl3 gave, after 1
week, a turquoise solid in 59% yield. M.p. 140 8C (dec.).
Anal. Calc. for C44H72Br2N4NiO6Si4: C, 48.9; H, 6.7; N,
5.3. Found: C, 49.2; H, 6.7; N, 5.3%.
3.1.5.2. Mn[O(iPr2SiOCH2py)2]2Br2. This white com-
plex separated over a period of 30 min from a solution
of MnBr2×
/
4H2O (0.014 g) and II (0.046 g) in isopropa-
138 8C. Anal. Calc.
for C48H80Br2MnN4O6Si4: C, 50.7; H, 7.1; N, 4.9.
nol (1.5 cm3). Yield: 58%, m.p. 136ꢁ
/
3.1.4.7. Ni[O(iPr2SiOpy)2]2(NO3)2. This complex se-
parated as a turquoise solid over a period of 24 h from
Found: C, 50.9; H, 8.1; N, 5.0%.
an isopropanol solution (1.5 cm3) of Ni(NO3)2×
/6H2O
3.1.5.3. Mn[O(iPr2SiOCH2py)2]2(NO3)2×
This separated in 26% yield as a white, crystalline solid
from a solution of Mn(NO3)2×4H2O (0.013 g) and II
(0.046 g) in isopropanol (1 cm3) after 1 day. M.p. 146ꢁ
/(H2O)2.
(0.015 g) and I (0.043 g). Yield: 63%. Anal. Calc. for
C44H72N6NiO12Si4: C, 50.5; H, 6.9; N, 8.0. Found: C,
50.8; H, 6.8; N, 8.0%.
/
/
147 8C. Anal. Calc. for C48H84MnN6O14Si4: C, 50.7; H,
7.5; N, 7.4. Found: C, 51.1; H, 6.7; N, 7.7%.
3.1.4.8. Ni[O(iPr2SiOpy)2]2(NCS)2. This was ob-
tained as a lilac solid in 67% yield from nickel(II)
thiocyanate and I by the method used for the nickel
bromide complex. Anal. Calc. for C46H72N6NiO6S2Si4:
C, 53.2; H, 7.0; N, 8.1. Found: C, 53.8; H, 7.2; N, 8.2%.
IR (cmꢂ1): 2072vs [n(NC), thiocyanate].
3.1.5.4. Mn[O(iPr2SiOCH2py)2]2(NCS)2. Addition of
a solution of Mn(NCS)2 (0.09 g) in EtOH (1 cm3) to II
in MeCN (1 cm3) and a few drops of CHCl3 gave a white
crystalline solid in 64% yield after 1 week. M.p. 265ꢁ
/
266 8C. Anal. Calc. for C50H80MnN6O6S2Si4: C, 55.0;
H, 7.4; N, 7.7. Found: C, 55.2; H, 7.8; N, 7.5%. IR
(cmꢂ1): 2045vs [n(NC), thiocyanate].
3.1.4.9. Complexes of copper(II) chloride with O(iPr2-
SiOpy)2. Reaction of CuCl2×
/
2H2O (0.008 g) with I
blue solution
(0.086 g) in MeOH (2.5 cm3) gave a greenꢁ
/
3.1.5.5. Co[O(iPr2SiOCH2py)2]2Cl2. Layering solu-
which initially (within 30 min) afforded small dichroic
(light blue/dark blue) prisms (compound A) which, on
standing overnight changed to blue needles (compound
B). When the reaction was carried out using more
tions of CoCl2×
/
6H2O (0.012 g) in EtOH (1 cm3) and a
solution of II (0.046 g) in MeCN (1 cm3) and a few
drops of CHCl3, with a buffer layer of EtOH (1 cm3)
concentrated solutions (0.016 g of CuCl2×
/
2H2O and
gave a pink solid after 3 weeks. Yield: 48%, m.p. 104ꢁ
/
0.172 g of I in 3 cm3 MeOH) a mixture of two types of
crystalline product was again formed after 12 h, the blue
dichroic prisms (compound A) and some pale blue
prisms (compound C). All three crystal types A, B and
C were characterised by X-ray crystallography.
106 8C. Anal. Calc. for C48H80Cl2CoN4O6Si4: C, 54.9;
H, 7.7; N, 5.3. Found: C, 54.8; H, 8.4; N, 5.2%.
3.1.5.6. Co[O(iPr2SiOCH2py)2]Br2. A blue crystalline
solid started to form within 10 min from a solution of
CoBr2×
/
6H2O (0.011 g) and II (0.046 g) in isopropanol (3
3.1.4.10. Zn[O(iPr2SiOpy)2]2(NCS)2. Addition of a
solution of Zn(NCS)2 (0.009 g) in EtOH (1 cm3) to
neat I (0.043 g) gave an immediate white precipitate.
Yield: 59%, m.p. 118 8C. Anal. Calc. for C46H72N6-
O6S2Si4Zn: C, 52.9; H, 7.0; N, 8.1. Found: C, 52.3; H,
7.0; N, 7.6%. IR (cmꢂ1): 2054vs [n(NC), thiocyanate].
cm3). Yield: 41%, m.p. 150 8C. Anal. Calc. for
C24H40Br2CoN2O3Si2: C, 42.4; H, 5.9; N, 4.1. Found:
C, 43.1; H, 5.3; N, 3.8%. IR (cmꢂ1): 244, 280 [n(CoBr)].
3.1.5.7. Co[O(iPr2SiOCH2py)2]2I2. An orange solid
separated over a period of 24 h from a solution of
CoI2 (0.031 g) and II (0.092 g) in EtOH (1.5 cm3) and
was collected and dried. Yield: 45%. Anal. Calc. for
C48H80CoI2N4O6Si4: C, 46.7; H, 6.5; N, 4.5. Found: C,
46.3; H, 6.4; N, 4.3%. A small, crystalline sample grown
by the layering method was found by X-ray crystal-
lography to have the formula: Co[O(iPr2SiOCH2-
py)2]2I2(H2O)2.
3.1.4.11. Ag[O(iPr2SiOpy)2](NO3). Addition of a so-
lution of AgNO3 (0.017 g) in a mixture of isopropanol
(0.5 cm3) and EtOH (2 cm3) to I (0.043 g) in isopropanol
(0.5 cm3) gave brown/gold crystals after 2 days. Yield:
52%, m.p. 138 8C. Anal. Calc. for C22H36AgN3O6Si2:
C, 43.9; H, 6.0; N, 7.0. Found: C, 44.2; H, 6.0; N, 6.9%.

D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ
/
73
71
3.1.5.8. Co[O(iPr2SiOCH2py)2]2(NO3)2. Addition of
a solution of Co(NO3)2×6H2O (0.015g) in EtOH (0.5
cm3) to neat II (0.046 g) gave an orange precipitate in
63% yield. M.p. 142ꢁ146 8C. Anal. Calc. for C48H80Co-
3.1.5.16. Zn[O(iPr2SiOCH2py)2]I2. This white com-
plex separated immediately on ‘layering’ a solution of
zinc iodide (0.016 g) in EtOH (0.5 cm3) on to a solution
of II in EtOH (2.5 cm3) containing a few drops of
/
/
N6O12Si4: C, 52.2; H, 7.3; N, 7.6. Found: C, 51.6; H, 7.3;
N, 7.5%.
CHCl3. Yield: 77%, m.p. 160ꢁ165 8C. Anal. Calc. for
C24H40I2N2O3Si2Zn: C, 37.0; H, 5.2; N, 3.6. Found: C,
36.5; H, 5.0; N, 3.4%. IR (cmꢂ1): 220 [n(ZnI)].
/
3.1.5.9. Co[O(iPr2SiOCH2py)2]2(NCS)2. Addition of
a solution of cobalt(II) thiocyanate (0.09 g) in EtOH (1
cm3) to neat II (0.046 g) gave an immediate pink
3.1.5.17. Zn[O(iPr2SiOCH2py)2](NO3)2. This white
complex separated overnight from
a
solution of
precipitate. Yield: 73%, m.p. 145ꢁ
/
146 8C. Anal. Calc.
Zn(NO3)2×
/
6H2O (0.028 g) and II (0.046 g) in isopropa-
for C50H80CoN6O6S2Si4: C, 54.8; H, 7.4; N, 7.7. Found:
C, 55.1; H, 7.2; N, 7.6%. IR (cmꢂ1): 2058vs [n(NC),
thiocyanate].
nol (2 cm3). Yield: 78%, m.p. 153 8C. Anal. Calc. for
C24H40N4O9Si2Zn: C, 44.4; H, 6.2; N, 8.6. Found: C,
44.8; H, 6.3; N, 8.5%.
3.1.5.10. Ni[O(iPr2SiOCH2py)2]2Cl2. A mixture of
3.1.5.18. Zn[O(iPr2SiOCH2py)2](NCS)2. Layering a
solution of zinc thiocyanate (0.009 g) in EtOH (0.5
cm3) onto a solution of II (0.046 g) in MeCN (1 cm3)
and a few drops of CHCl3, with a ‘buffer’ layer of
MeOH, gave colourless crystals in 3 days in 30% yield.
M.p. 183 8C. Anal. Calc. for C26H40N4O3S2Si2Zn: C,
48.6; H, 6.3; N, 8.7. Found: C, 48.8; H, 6.3; N, 8.7%. IR
(cmꢂ1): 2072vs [n(NC), thiocyanate].
NiCl2×
g) in MeCN (1 cm3) and a few drops of CHCl3, gave a
turquoise solid after 3 weeks. Yield: 57%, m.p. 256ꢁ
/
6H2O (0.012 g) in MeOH (1 cm3) and II (0.046
/
258 8C. Anal. Calc. for C48H80Cl2N4NiO6Si4: C, 54.9;
H, 7.7; N, 5.3. Found: C, 54.1; H, 8.0; N, 5.0%.
3.1.5.11. Ni[O(iPr2SiOCH2py)2]2(NO3)2×
6H2O (0.015 g) in EtOH (0.5
/(H2O)2.
Addition of Ni(NO3)2×
/
cm3) to neat II (0.046 g) gave a light blue precipitate
after 2 days. Yield: 63%, m.p. 152 8C. Anal. Calc. for
C48H84N6NiO14Si4: C, 50.6; H, 7.4; N, 7.4. Found: C,
50.0; H, 7.6; N, 7.1%.
3.1.5.19. Ag[O(iPr2SiOCH2py)2](NO3). This complex
separated, over a period of 1 month, as colourless
crystals from a solution of AgNO3 (0.017 g) and II
(0.046 g) in MeCN (2 cm3) and a few drops of CHCl3.
Yield: 63%, m.p. 196ꢁ198 8C. Anal. Calc. for C24H40-
AgN3O6Si2: C, 45.7; H, 6.4; N, 6.7. Found: C, 45.9; H,
6.4; N, 6.5%.
/
3.1.5.12. Ni[O(iPr2SiOCH2py)2]2(NCS)2. This light
blue complex was obtained as for the Mn analogue.
Yield: 88%, m.p. 287ꢁ289 8C. Anal. Calc. for C50H80-
N6NiO6S2Si4: C, 54.8; H, 7.4; N, 7.7. Found: C, 55.4; H,
7.5; N, 7.5%. IR (cmꢂ1): 2065vs [n(NC), thiocyanate].
/
3.1.5.20. Ag[O(iPr2SiOCH2py)2](CF3SO3). Layering
a solution of AgCF3SO3 (0.026 g) in EtOH (1 cm3)
and II (0.046 g) in MeCN (1 cm3) and a few drops of
CHCl3 gave a colourless solid after 3 weeks. Yield: 71%,
3.1.5.13. Cu2[O(iPr2SiOCH2py)2](C3H7CO2)4.
A
MeOH solution of copper(II) n-butyrate (0.026 g) in
MeOH (1 cm3) was layered on top of a solution of II
(0.023 g) in MeCN (1.5 cm3). Green crystals formed
over a period of 2 weeks. Yield: 36%, m.p. 134 8C.
Anal. Calc. for C40H68Cu2N2O11Si2: C, 51.3; H, 7.3; N,
3.0. Found: C, 51.4; H, 7.5; N, 2.9%.
m.p. 187ꢁ190 8C. Anal. Calc. for C25H40AgF3N2O6-
SSi2: C, 41.9; H, 5.6; N, 3.9. Found: C, 42.6; H, 5.4; N,
3.8%.
/
3.1.5.21. Cd[O(iPr2SiOCH2py)2]Cl2. This white com-
plex separated immediately on adding a solution of
CdCl2 (0.009 g) in water (0.5 cm3) to a solution of II in
EtOH (0.5 cm3). Yield: 58%, m.p. 122 8C. Anal. Calc.
for C48H80CdCl2N4O6Si4: C, 52.2; H, 7.3; N, 5.1.
Found: C, 52.5; H, 7.3; N, 4.6%.
3.1.5.14. Zn[O(iPr2SiOCH2py)2]Cl2. Addition of
ZnCl2 (0.007 g) in isopropanol (0.5 cm3) to a solution
of II (0.046 g) also in isopropanol (0.5 cm3) gave an
immediate white precipitate. Yield: 77%, m.p. 147ꢁ
/
148 8C. Anal. Calc. for C24H40Cl2N2O3Si2Zn: C, 48.3;
H, 6.8; N, 4.7. Found: C, 48.5; H, 6.2; N, 4.5%. IR
(cmꢂ1): 303, 342 [n(ZnCl)].
3.1.5.22. Cd[O(iPr2SiOCH2py)2]Br2. This white com-
plex was obtained as for the previous compound but
using cadmium bromide. Yield: 60%, m.p. 101ꢁ102 8C.
/
Anal. Calc. for C48H80Br2CdN4O6Si4: C, 48.3; H, 6.8;
N, 4.7. Found: C, 47.9; H, 6.7; N, 4.5%.
3.1.5.15. Zn[O(iPr2SiOCH2py)2]Br2. This was ob-
tained as for the analogous chloride. Yield: 70%, m.p.
158ꢁ
/
159 8C. Anal. Calc. for C24H40Br2N2O3Si2Zn: C,
3.1.5.23. Cd[O(iPr2SiOCH2py)2]2(NO3)2×
Addition of Cd(NO3)2×
4H2O (0.015 g) in EtOH (1 cm3)
to II (0.046 g) in MeCN (1 cm3) and a few drops of
/(H2O)2.
42.2; H, 5.9; N, 4.1. Found: C, 42.8; H, 5.7; N, 4.0%. IR
(cmꢂ1): 225, 265 [n(ZnBr)].
/

72
D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ73
/
CHCl3 gave a white precipitate. Yield: 95%, m.p.
128 8C. Anal. Calc. for C48H84CdN6O14Si4: C, 48.2;
H, 7.1; N, 7.0. Found: C, 48.8; H, 7.4; N, 6.6%.
to III (0.052 g) in EtOH (0.5 cm3) gave an immediate
white precipitate. Yield: 56%, m.p. 84 8C. Anal. Calc.
for C58H96N6O6S2Si4Zn: C, 57.4; H, 8.0; N, 6.9. Found:
C, 57.3; H, 8.0; N, 6.8%. IR (cmꢂ1): 2065vs [n(NC),
thiocyanate].
3.1.6. Complexes of ligand III
3.1.6.1. Mn[O(iPr2SiO(CH2)3py)2]Cl2. Addition of a
3.2. Microanalyses and spectroscopic measurements
solution of MnCl2×
solution of III (0.052 g) in MeCN (2 cm3) gave a white
solid overnight. Yield: 17%, m.p. 152ꢁ154 8C. Anal.
/4H2O (0.01 g) in isopropanol to a
Elemental analyses were performed by the Scientific
Analysis and Consultancy Service, University of North
London. IR spectra were recorded on an ATI Mattson
Research Series FT spectrometer as KBr discs. Electro-
nic spectra were obtained on powdered samples by the
reflectance method using a Beckman DK2 spectrometer.
EPR measurements for the complexes Mn[O(iPr2-
SiOCH2py)2]2Cl2 and Mn[O(iPr2SiOpy)2]2Br2 were ob-
tained at the EPSRC c.w. EPR Service Centre,
Department of Chemistry, University of Manchester.
The spectra were measured on powder samples at X-
band frequency (EMX spectrometer) at r.t. and approxi-
mately 107 K and at Q-band frequency (ESP 300
Spectrometer) at r.t. and at approximately 120 K. The
other EPR spectra were measured on powder samples at
r.t. using a Varian E12 X-band spectrometer at Imperial
College.
/
Calc. for C28H48Cl2MnN2O3Si2: C, 52.3; H, 7.5; N, 4.4.
Found: C, 51.7; H, 7.9; N, 4.2%. IR (cmꢂ1): 318, 344
[n(MnCl)].
3.1.6.2. Mn[O(iPr2SiO(CH2)3py)2]2(NCS)2.
This
white compound was obtained in 17% yield by the
method used for the complex Co[O(iPr2SiOCH2py)2]2I2.
Anal. Calc. for C58H96MnN6O6S2Si2: C, 57.8; H, 8.0; N,
7.0. Found: C, 58.2; H, 7.7; N, 6.8%. IR (cmꢂ1): 2052vs
[n(NC), thiocyanate].
3.1.6.3. Co[O(iPr2SiO(CH2)3py)2]Cl2. Addition of a
solution of CoCl2×
/
6H2O (0.012 g) in isopropanol to a
solution of III (0.052 g) in isopropanol (2 cm3) gave an
immediate blue precipitate. Yield: 93%, m.p. 164 8C.
Anal. Calc. for C28H48Cl2CoN2O3Si2: C, 52.0; H, 7.5; N,
4.3. Found: C, 52.0; H, 7.2; N, 4.1%. IR (cmꢂ1): 307,
342 [n(CoCl)].
3.3. X-ray studies
A summary of the crystal data and of the data
collection and refinement parameters for compounds
3.1.6.4. Co[O(iPr2SiO(CH2)3py)2]Br2. This blue com-
pound was obtained in 52% yield as for the chloride
1ꢁ
using the SHELXTL PC program system [28]. Selected
bond lengths and angles for 1ꢁ6 are given in Tables 3ꢁ8,
/6 is given in Table 8. Computations were carried out
analogue. M.p. 177ꢁ181 8C. Anal. Calc. for
/
C28H48Br2CoN2O3Si2: C, 45.7; H, 6.6; N, 3.8. Found:
C, 46.5; H, 6.5; N, 3.6%. IR (cmꢂ1): 244, 274 [n(CoBr)].
/
/
respectively.
3.1.6.5. Co[O(iPr2SiO(CH2)3py)2]2(NCS)2.
peach-coloured compound was obtained in 74% yield
as for the Mn analogue. M.p. 150ꢁ151 8C. Anal. Calc.
This
4. Supplementary material
/
for C58H96CoN6O6S2Si2: C, 57.6; H, 8.0; N, 7.0. Found:
C, 58.1; H, 8.7; N, 6.9%. IR (cmꢂ1): 2065vs [n(NC),
thiocyanate].
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 189204ꢁ
/
189209 for com-
3.1.6.6. Zn[O(iPr2SiO(CH2)3py)2]Cl2. Obtained as
for the Co analogue as a white compound. Yield: 61%,
pounds 1ꢁ6, respectively. Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
/
m.p. 178ꢁ181 8C. Anal. Calc. for C28H48Cl2N2O3-
/
(fax:
ac.uk or www: http://www.ccdc.cam.ac.uk).
ꢃ44-1223-336-033; e-mail: deposit@ccdc.cam.
/
Si2Zn: C, 51.5; H, 7.4; N, 4.3. Found: C, 52.6; H, 7.2;
N, 4.2%. IR (cmꢂ1): 296, 332 [n(ZnCl)].
3.1.6.7. Zn[O(iPr2SiO(CH2)3py)2]Br2. This white
compound was obtained in 79% yield as for the Co
analogue. M.p. 176 8C. Anal. Calc. for C28H48Br2-
N2O3Si2Zn: C, 45.5; H, 6.6; N, 3.8. Found: C, 46.0; H,
5.9; N, 3.6%. IR (cmꢂ1): 220, 254 [n(ZnBr)].
Acknowledgements
We thank the EPSRC for a Research Studentship (to
SJR) and for equipment, and Dr David Collison, Dr
Eric McInnes and Dr Jing Zhao of the EPSRC c.w. EPR
Service Centre, University of Manchester, for EPR
measurements and simulations.
3.1.6.8. Zn[O(iPr2SiO(CH2)3py)2]2(NCS)2. Addition
of a solution of Zn(NCS)2 (0.009 g) in EtOH (0.5 cm3)

D.M.L. Goodgame et al. / Inorganica Chimica Acta 343 (2003) 61ꢁ
/
73
73
Table 8
Crystal data, data collection and refinement parameters for compounds 1ꢁ
a
/
6
Data
1
2
3
4
5
6
Formula
C44H72Cl2Co-
N4O6Si4
C48H80Cl2Mn-
N4O6Si4
C48H84CoI2-
N4O8Si4
C44H72Cl2Cu-
N4O6Si4
2MeOH
C22H36Cl2Cu-
N2O3Si2
C44H72Cl1.5Cu-
N4O6Si4
3MeOH
Solvent
Formula weight
Colour, habit
995.3
pink prisms
1047.4
1270.3
1063.9
pale blue blocks
567.2
blue needles
1078.3
colourless
platy needles
293
colourless
platy prisms
183
dark/light blue
dichroic prisms
183
Temperature (K)
Crystal system
Space group
203
triclinic
¯
P1 (no. 2)
293
triclinic
¯
P1 (no. 2)
183
triclinic
¯
P1 (no. 2)
triclinic
¯
P1 (no. 2)
monoclinic
P21/n (no. 14)
8.570(2)
tetragonal
P4/ncc (no. 130)
17.995(1)
/
/
/
/
˚
a (A)
8.616(6)
8.952(9)
17.575(14)
83.46(7)
87.55(6)
76.83(7)
1311(2)
8.817(1)
10.003(1)
17.116(1)
99.95(1)
101.16(1)
97.55(1)
1437.3(2)
8.662(2)
18.321(2)
21.358(7)
70.31(2)
89.69(2)
79.15(1)
3128(1)
2
8.996(1)
9.520(1)
17.122(1)
95.14(1)
97.32(1)
97.73(1)
1432.7(2)
˚
b (A)
16.946(3)
19.057(5)
˚
c (A)
37.768(3)
a (8)
b (8)
g (8)
V (A )
Z
Dcalc (g cmꢂ3
90.00(3)
3
˚
2768(1)
4
1.361
12229(1)
c
b
b
b
1
1
1
8
1.171
)
1.260
Mo Ka
0.57
1.210
Cu Ka
3.89
1.349
Cu Ka
11.01
1.233
Mo Ka
0.61
d
d
d
Radiation used
m (mmꢂ1
Cu Ka
3.92
Cu Ka
2.25
)
Crystal size (mm)
u Range (8)
Unique reflections
0.60ꢄ
/
0.33ꢄ
/
0.32 0.77ꢄ
/
0.33ꢄ
/
0.20 0.33ꢄ
/
0.17ꢄ
/
0.17 1.00ꢄ
/
0.90ꢄ
/
0.77 0.37ꢄ
/
0.10ꢄ
/
0.08 0.67ꢄ
/
0.67ꢄ0.40
/
2.3ꢁ27.5
/
2.7ꢁ60.0
/
2.2ꢁ60.0
/
2.2ꢁ22.5
/
2.3ꢁ64.0
/
2.3ꢁ60.0
/
6019
4766
4219
3396
8983
5523
3720
2406
4569
4315
4539
3026
measured
Unique reflections
observed [jFojꢀ4s(jFoj)]
/
Absorption correction
Max./min. transmission
Variables
gaussian
0.51, 0.24
343
ellipsoidal
0.30, 0.20
664
ellipsoidal
0.57, 0.49
339
empirical
0.78, 0.37
290
277
0.038, 0.083
341
0.066, 0.159
e
R1, wR2
0.045, 0.110
0.077, 0.178
0.061, 0.135
0.040, 0.100
a
Details in common: graphite monochromated radiation, refinement based on F2.
The complex has crystallographic Ci symmetry.
The complex has crystallographic C4 symmetry.
Rotating anode source.
b
c
d
e
R1ꢀ
/
a jjFojꢂ
/
jFcjj/a jFoj; wR2ꢀ
/
{a [w(Fo2ꢂ
/
Fc2)2]/a [w(Fo2)2]}1/2; wꢂ1ꢀ
/
s2(Fo2)ꢃ
/
(aP)2ꢃ
/bP.
[15] G.J. Long, P.J. Clarke, Inorg. Chem. 17 (1978) 1394.
[16] H. Xu, J. Ji, Z. Wu, J. Zou, Z. Xu, X. You, Polyhedron 12 (1993)
2261.
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