Copper(II) nitrite complexes of tripodal ligands derived from 1,1,1-tris(2-pyridyl)methylamine

Article abstract of DOI:10.1016/S0020-1693(02)01487-1

Copper nitrite complexes of stoichiometric formulae [Cu(NO₂)_nL] (n=1 or 2), where L is a Schiff base or amide derivative of 1,1,1-tris(2-pyridyl)methylamine, have been prepared and characterized. The crystal structures of the mononuclear Schiff base complex [Cu(NO₂)₂(tpmbz)] [tpmbz=(C₅H₄N)₃CN=CHC₆H ₅], the nitrite-bridged dinuclear Schiff base complex [{Cu(NO₂)(tpmsal)}₂]·Et₂O [tpmsalH=(C₅H₄N)₃CN=CHC₆H ₄OH-2] and the polymeric amide complex [{Cu(NO₂)(tpms)}_n]·nH₂O [tpmsH=(C₅H₄N)₃CNHC(O)CH₂CH ₂CO₂H] are reported.

Full text of DOI:10.1016/S0020-1693(02)01487-1

Inorganica Chimica Acta 348 (2003) 143Á149
/
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Copper(II) nitrite complexes of tripodal ligands derived from 1,1,1-
tris(2-pyridyl)methylamine
Phillip J. Arnold a, Sian C. Davies b, Marcus C. Durrant b,*, D. Vaughan Griffiths a,
David L. Hughes b, Philip C. Sharpe a
a Department of Chemistry, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
b Department of Biological Chemistry, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
Received 6 September 2002; accepted 18 November 2002
Abstract
Copper nitrite complexes of stoichiometric formulae [Cu(NO2)nL] (nꢀ
1,1,1-tris(2-pyridyl)methylamine, have been prepared and characterized. The crystal structures of the mononuclear Schiff base
complex [Cu(NO2)2(tpmbz)] [tpmbzꢀ CHC6H5], the nitrite-bridged dinuclear Schiff base complex
[{Cu(NO2)(tpmsal)}2]×Et2O [tpmsalHꢀ(C5H4N)3CNÄ
nH2O [tpmsHꢀ(C5H4N)3CNHC(O)CH2CH2CO2H] are reported.
/1 or 2), where L is a Schiff base or amide derivative of
/
(C5H4N)3CNÄ
/
/
/
/
CHC6H4OH-2] and the polymeric amide complex [{Cu(NO2)(tpms)}n]×
/
/
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Copper; Crystal structures; Nitrite; Schiff bases; Tripodal ligands
1. Introduction
which the primary amino group has been derivatised to
Schiff base and amide functions.
Catalysis by molecular transition metal complexes
requires supporting ligands which are sufficiently robust
to mediate a variety of chemical processes without
degradation, yet also versatile and capable of modifica-
tion. We have recently developed a new class of tripodal
ligand based on 1,1,1-tris-(2-pyridyl)methylamine (tpm)
which fulfils these requirements [1]. In particular, we
have examined the coordination chemistry of tpm and
its derivatives with copper, inspired by the importance
of copper enzymes in which the active site Cu is ligated
by three histidines, especially nitrite reductase [2]. Our
earlier studies showed that these ligands produce a
considerable variety of copper complexes, in which the
metal is coordinated by two or three of the pyridine
rings, and sometimes in the case of tpm itself by the
amino group also. In this paper we report the extension
of this work to the preparation and characterization of
copper nitrite complexes of ligands derived from tpm in
2. Results and discussion
The ligands used in this study are illustrated in
Scheme 1. Reaction of Cu(NO2)2, prepared in situ
from CuSO4 or Cu(OAc)2 and NaNO2, with these
amide or Schiff base derivatives gave the corresponding
copper nitrite complexes. The formulae, analytical and
solution conductivity data for the complexes are given in
Table 1. Two nitrito ligands were retained for the
complexes of the non-ionizable ligands tpml, tpma and
tpmbz (1, 2 and 3 respectively), whereas for the ligands
containing acidic functional groups LH, namely
tpmsalH and tpmsH, complexes 4 and 5, of stoichio-
metric formulae [Cu(NO2)(L)], were obtained. All of the
complexes are non-electrolytes in acetonitrile solution,
showing that the nitrito ligands are in all cases
coordinated to the metal. As well as determining the
number of nitrito ligands in each complex, the organic
ligand has a marked influence on the solubilities of the
individual complexes; for example, the tpml complex 1 is
soluble in dichloromethane and acetonitrile but not in
* Corresponding author. Tel.: ꢁ
3450-021.
E-mail address: marcus.durrant@bbsrc.ac.uk (M.C. Durrant).
/
44-160-3450-704; fax: ꢁ44-160-
/
0020-1693/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(02)01487-1

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P.J. Arnold et al. / Inorganica Chimica Acta 348 (2003) 143Á149
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tions, coordinated through either O(61a) or O(61b). In
all cases, the Cu is five-coordinate with a square-
pyramidal geometry; the apical atoms are N(11) or
N(31) of the tpmbz ligand. This is coordinated to the
metal via its three pyridine rings in a fac pattern, similar
to the majority of complexes of tpm and its derivatives
[1]. The imino nitrogen in complex 3 is not involved in
coordination. However, the inclusion of a phenolic
sidechain in the Schiff base, as in tpmsalH, results in
the coordination of both the imine nitrogen and the
deprotonated phenol oxygen to give complex 4. The X-
ray crystal structure of this complex, Fig. 2, shows it to
be a dimer, in which the square-pyramidal coordination
sphere around the copper is achieved by means of
bridging nitrite groups. The tpmsalꢂ ligand is still three-
coordinate (in mer form, occupying three of the square
base sites), with two of the pyridine rings distant from
the metal. Thus, although molecular models suggest that
tpmsalꢂ could adopt a somewhat strained tetradentate
coordination mode, in practice this is less favourable
than completion of the coordination sphere by nitrite
bridging.
Scheme 1.
Use of all three pyridine nitrogens as well as the
carboxylate sidechain of the carboxylic acid derivative
tpmsH is achieved in complex 5 (Fig. 3); this complex
forms an infinite polymer in the solid state, in which
individual tpmsꢂ ligands span two copper atoms,
providing a tris-pyridyl donor set to the first and a
carboxylato group to the second. Complex 5 is insoluble
in organic solvents, including DMF, but does dissolve in
hot water. Moreover, freshly-prepared solutions of the
complex in alcohol/water mixtures are stable for several
days. The X-ray crystal structure of 5 shows that the
nitrite is coordinated via a single oxygen atom. The
NHCOCH2CH2CO2ꢂ arm in complex 5 shows an
interesting difference from that in [Cu(tpms)2], whose
crystal structure we described previously [1b]; whereas
the latter is close to the ideal all-trans planar arrange-
ment, in complex 5 there is disorder in this group but in
the major component (86% occupancy), the three C-C
bonds of the arm have gauche torsion angles, of 72.5(5),
methanol or water, a pattern more usually associated
with copper(I) complexes. The Schiff base complex 3
appears to be quite stable in solution, in contrast to the
sulfato complex [Cu(SO4)(tpmbz)], which we were un-
able to isolate in pure form; this species decomposes
readily via hydrolysis of the Schiff base to give
[Cu(SO4)(tpm)(H2O)] plus benzaldehyde [1b].
The X-ray crystal structures of complexes 3, 4 and 5
have been obtained, and principal molecular dimensions
are collated in Table 2. Complex 3 has the simplest
structure, consisting of discrete molecules of
[Cu(NO2)2(tpmbz)], Fig. 1. Both nitrito ligands are
coordinated through a single O atom, though there is
disorder in both. Thus, the nitrito ligand denoted by
atoms 51Á/54 in Fig. 1 binds at either of two coordina-
tion sites, as O(51)Á
/
N(52)ÁO(53) or as O(54)ÁN(53)Á
/
/
/
O(52). The second nitrito ligand adopts several orienta-
Table 1
Colours, conductivities and microanalytical dataa for the complexes
Complex
Colour
LM b(S cm2 molꢂ1
)
Analysis (%)
C
H
N
1 [Cu(NO2)2(tpml)]
green
green
green
11
6
55.6 (56.0)
46.0 (46.1)
54.5 (54.6)
55.0 (55.0)
48.5 (48.2)
6.0 (6.0)
3.5 (3.7)
3.6 (3.6)
3.7 (4.0)
4.0 (4.0)
13.6 (14.0)
17.8 (17.9)
16.7 (16.6)
13.5 (14.0)
14.0 (14.1)
2 [Cu(NO2)2(tpma)]×
3 [Cu(NO2)2(tpmbz)]
/
0.5H2O
5
4 [{Cu(NO2)(tpmsal)}2]×
5 [Cu(NO2)(tpms)]×1.5H2O
/3H2O
green
turquoise
6
53 c
/
a
Calculated values in parentheses. Note that differences in solvent of crystallization compared to Table 3 arises from the different conditions used
in the X-ray crystallization experiments.
b
In MeCN unless stated otherwise. Accepted range [6] for a 1:1 electrolyte in MeCN is 120Á .
160 S cm2 molꢂ1
/
c
Complex poorly soluble in neat MeCN; measurement done in MeCNꢁ20% H2O.
/

P.J. Arnold et al. / Inorganica Chimica Acta 348 (2003) 143Á
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149
145
Table 2
Selected molecular dimensions in complexes 3, 4 and 5 (bond lengths (A) and bond angles (8); e.s.d.’s are in parentheses)
˚
Complex 3
Complex 4
Complex 5
Bond lengths
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
/
N(11)
N(21)
N(31)
O(51)
O(54)
O(61a)
O(61b)
2.138(3)
2.034(3)
2.080(3)
2.022(4)
1.83(2)
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
/
O(1)
1.871(7)
1.925(8)
1.970(9)
2.002(8)
2.524(9)
1.984(3)
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
/
N(11)
2.022(3)
2.007(3)
2.220(3)
2.738(4)
1.958(4)
2.08(3)
/
/N(3)
/N(21)
/
/
N(332)
O(41)
O(41I)
O(51)
/N(31)
/
/
/
O(441II)
O(442II)
O(44aII)
O(44bII)
/
/
/
/
2.033(11)
1.953(8)
/
/
/
/
2.47(3)
Bond angles
N(21)ÁCuÁ
N(31)ÁCuÁ
O(51)ÁCuÁ
O(54)ÁCuÁ
O(61a)Á
O(61b)Á
N(21)ÁCuÁ
O(51)ÁCuÁ
O(54)ÁCuÁ
O(61a)Á
O(61b)Á
O(51)ÁCuÁ
O(54)ÁCuÁ
O(61a)ÁCuÁ
O(61b)ÁCuÁ
O(51)ÁCuÁ
O(61b)Á
O(54)ÁCuÁ
O(54)ÁCuÁ
/
/
N(11)
85.04(12)
87.68(11)
100.62(14)
165.0(4)
90.1(4)
O(1)Á
O(1)Á
O(1)Á
O(1)Á
N(3)Á
N(3)Á
N(3)Á
N(332)Á
N(332)Á
O(41)ÁCuÁ
/
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
CuÁ
/
N(3)
94.1(4)
174.7(4)
88.0(3)
91.4(3)
83.6(4)
177.8(4)
105.2(3)
94.3(3)
93.7(3)
75.3(4)
N(21)Á
N(11)Á
O(442II)Á
O(51)ÁCuÁ
N(21)ÁCuÁ
O(442II)Á
O(51)ÁCuÁ
O(442II)Á
O(51)ÁCuÁ
O(442II)Á
CuÁ
N(11)ÁCuÁ
N(21)ÁCuÁ
O(44aII)Á
O(51)ÁCuÁ
/
CuÁ
/
N(11)
85.72(11)
88.77(10)
169.23(13)
86.59(11)
84.36(11)
95.37(13)
171.94(11)
101.99(12)
97.90(11)
91.74(12)
113.7(7)
/
/N(11)
/
/
N(332)
O(41)
O(41I)
/CuÁ
/
N(31)
/
/N(11)
/
/
/
CuÁ
N(11)
N(31)
/N(11)
/
/N(11)
/
/
/
/
/
CuÁ
CuÁ
/N(11)
/
/
N(332)
/
/
/
/N(11)
112.9(3)
86.57(11)
92.81(14)
97.1(4)
/
/
O(41)
O(41I)
/CuÁ
/N(21)
/
/N(31)
/
/
/
/
N(21)
/
/N(21)
/CuÁ
/
O(41)
O(41I)
/CuÁ
/N(31)
/
/N(21)
/CuÁ
/
/
/
N(31)
/
CuÁ
/N(21)
169.8(4)
161.2(3)
171.59(14)
107.2(4)
102.1(4)
88.7(2)
/
/
O(41I)
/
/O(51)
/
CuÁ
/
N(21)
N(31)
N(31)
/
/
O(44aII)
O(44aII)
/
/
/
/
92.9(7)
/
/
/CuÁ
/N(31)
157.1(7)
88.0(7)
/
/N(31)
/
/
O(44aII)
/
/N(31)
/
/O(61a)
79.3(3)
/
CuÁ
/O(51)
89.2(2)
85.4(5)
/
/O(61a)
/
/O(61b)
67.0(5)
Proposed hydrogen bonding in complex 5
DÁ
N(1)Á
O(6)Á
O(6)Á
O(6)Á
/
HÁ Á ÁA
DÁ
/
H
HÁ Á ÁA
2.43(4)
2.08(5)
1.70(6)
1.93(9)
DÁ Á ÁA
DÁ
/
HÁ Á ÁA
/
H(1)Á Á ÁO(53III
)
0.68(4)
0.93(5)
0.93(5)
1.10(9)
3.018(4)
2.986(6)
2.57(3)
3.022(5)
146(4)
163(4)
154(5)
171(7)
/
H(6a)Á Á ÁO(442IV
)
/
H(6a)Á Á ÁO(44bIV
)
/
H(6b)Á Á ÁO(41V)
Symmetry operations: in complex 4, I: 1ꢂ
/
x, ꢂ
/
y, ꢂ
/
z; in complex 5, II: x, 1/2ꢂ
/
y, zꢁ
/
1/2; III: 1/2ꢂ
/
x, 1/2ꢁ
/
y, z; IV: 1/2ꢂ
/
x, 1ꢂ
/
y, 1/2ꢁ
/
z; V: ꢂx,
/
1ꢂy, 1ꢂz.
/
/
62.4(5) and 84.2(5)/ꢂ
/
96.7(5)8 for the NCCC, CCCC
hydrogen atoms were located and refined) to the amide
oxygen atom O(41) and a carboxylate oxygen [in either
major O(442) or minor O(44b) orientation] in neigh-
bouring molecules; a rather wavy hydrogen-bonded
sheet is thus formed normal to the b axis. The polymer
chain zigzags between the sheets along the c axis to
create a rigid three-dimensional structure.
and the two CCCO angles, respectively. This most likely
results from the packing requirements of the polymer;
the sidechain is effectively coiled up to minimise the
overall length of the ligand. The minor component [with
alternative sites for C(43), O(441) and O(442)] is coiled
differently, with corresponding torsion angles of
The UVÁ
weak copper(II) dÁ
4). In addition, all of these nitrito complexes show a
band at 360Á380 nm; however the assignment of this
band to nitrite must be treated with caution since the
spectra of some related non-nitrito complexes also show
/
Vis spectra of all five complexes show a
122.8(12), ꢂ
/
38(2) and 149(2)/ꢂ11(3)8. Due to this
/
/
d band at 600Á650 nm (see Section
/
disorder in the tpms tail group in complex 5, the
carboxylate group coordinates the next copper atom in
the polymeric chain in two distinct ways: the major
component has the arrangement shown in Fig. 3, but in
/
the remainder, the short CuÁ
/
O bond CuÁ
O(44aII) is
trans to N(31) and the second carboxylate oxygen atom
/
a shoulder at 336Á382 nm, probably associated with
/
II
O(44b ) is 2.47(3) A from the copper and trans to
˚
charge transfer [1]. The nitrite ligands generally give
medium intensity bands in the IR spectra of these
complexes, which could only be assigned with certainty
by isotopic substitution. The spectrum of the Schiff base
N(11). There is a rather weak hydrogen bond from the
amide NÁ
/
H to O(53) of an adjacent nitrite group, and
there are stronger bonds from the solvent water (whose

146
P.J. Arnold et al. / Inorganica Chimica Acta 348 (2003) 143Á149
/
Fig. 1. One molecule of [Cu(NO2)2(tpmbz)] (3) showing the atom
numbering scheme. Hydrogen atoms have been omitted for clarity (as
in all the figures). There is disorder in both nitrito ligands: one ligand is
bound principally through O(51) but, in ca. 19% of sites, alternatively
through O(54); the ligand of O(61), N(62), O(63) is found in several
conformations.
Fig. 3. One complex molecule in [{Cu(NO2)(tpms)}n ]×n(H2O) (5) in a
polymer chain. There is disorder in the carboxylate tail; the principal
arrangement is shown here.
/
complex 3 was clearest and gave bands assigned to the
14N nitrito group at 1377 [n(NÄ
ligands are monodentate, consistent with the X-ray
crystal structure (Fig. 1). The tpma complex 2 gave a
/
O)] and 1146 [n(NO)]
cmꢂ1, shifted to 1348 and 1123 cmꢂ1, respectively, for
similar n(NÄ
/
O) band at 1383 and 1367 cmꢂ1 for the 14
N
the 15N isotopomer. These are consistent with nitrito
and 15N isotopomers, respectively, but the lower fre-
quency band could not be assigned with certainty, even
with isotopic labelling, due to the presence of a number
of other bands in this region. The other nitrite com-
(CuÁ
the NO2ꢂ ligands [3]. The absence of a d(ONO) mode at
approximately 840Á
890 cmꢂ1 suggests that the nitrito
/
O) rather than the nitro (CuÁN) coordination of
/
/
Fig. 2. The Cu-complex molecule in [{Cu(NO2)(tpmsal)}2]×
/Et2O (4) in which the dimer lies about a centre of symmetry. Atoms labelled ‘n’ represent
the carbon atoms C(n).

P.J. Arnold et al. / Inorganica Chimica Acta 348 (2003) 143Á
/
149
147
plexes show similar spectroscopic features, suggesting
that in all these complexes nitrite is coordinated through
a single oxygen. The same was observed for the related
the solid was washed with EtOH and dried in vacuo,
then recrystallized from acetone as [Cu(NO2)2(tpml)] 1
(0.12 g, 44%). IR (KBr disc): 3385m (NH), 2926s,
2855m, 1695s (amide I), 1597m (py ring), 1508m,
1468s, 1437s, 1379m (NO2), 1269w, 1163m (NO2),
complex [Cu(NO2)(tepa)]PF6 (tepaꢀ
/
tris[2-(2-pyridy-
l)ethyl]amine) [4], whilst for [Cu(NO2)(tpa)]PF6 (tpaꢀ
/
tris[2-(2-pyridyl)methyl]amine) both nitrito and nitro
forms were observed in solution and characterized by
X-ray crystallography in the solid state [5].
1136w, 1053m, 789m, 756m, 660m and 579w cmꢂ1
.
UV (MeCN): 626 (o 121), 376 (o 1750) and 265 nm (o
15600).
4.3. Preparation of [Cu(NO2)2(tpma)] (2)
3. Conclusions
Following the same procedure as for 1 but using tpma
Five new complexes of general formula [Cu(NO2)nL],
where L is a Schiff base or amide derivative of 1,1,1-
rather than tpml gave [Cu(NO2)2(tpma)]×
/
0.5H2O 2 (37%
yield). IR (KBr disc): 3377m (NH), 1697s (amide I),
1597 (py ring), 1466s, 1437s, 1383m (NO2), 1269m,
1165w, 1140w, 1085m, 1061m, 1015w, 775m, 756m,
669m and 556m cmꢂ1. UV (MeCN): 637 (o 59), 377 (o
1680) and 264 nm (o 15900).
tris(2-pyridyl)methylamine (tpm) and nꢀ1 or 2, have
/
been prepared and characterized, three of them by X-ray
crystallography. The number of nitrito ligands and the
donor set employed by the organic ligand are deter-
mined by the nature of the group used to derivatise the
tpm. The present system also suggests that judicious
substitutions at the six-positions of the pyridine rings
might allow control of the mode of nitrite binding
through internal hydrogen bonding or electrostatic
effects and this is being investigated further. Complex
5 has a number of attributes which are of interest in the
context of nitrite reductase; the copper coordination
sphere of three pyridine nitrogens and two O-bound
ligands approaches the biologically characterised type 2
copper site, involving three histidine nitrogens and a
single O-bound nitrite. The linkage of copper centres in
the polymeric structure of 5 is particularly interesting as
it can be viewed as a first step towards building redox-
linked, differentiated copper centres, as found in the
enzyme [1].
4.4. Preparation of [Cu(NO2)2(tpmbz)] (3)
Use of the same procedure as for 1 but using tpmbz
rather than tpml gave [Cu(NO2)2(tpmbz)] 3 (25% yield).
IR (KBr disc): 3080w, 1641s (CÄ/N), 1601m (Ph ring),
1582m (py ring), 1460s, 1441s, 1377m (NO2), 1146s
(NO2), 1059m, 1024m, 853w, 773m, 758m, 692m, 658m,
573w, 557w and 523w cmꢂ1. UV (MeCN): 648 (o 70),
382 (o 2040) and 263 nm (o 42900).
4.5. Preparation of [{Cu(NO2)(tpmsal)}2] (4)
Cu(OAc)2×
/
H2O (0.15 g, 0.75 mmol) was dissolved in
warm EtOH (8 cm3) and the solution was added to a
suspension of tpmsalH (0.275 g, 0.75 mmol) in hot
EtOH (10 cm3) with stirring. The resulting dark green
solution was allowed to cool to room temperature. A
solution of NaNO2 (0.145 g, 1.5 mmol) in H2O (2.5 cm3)
was added, whereupon a solid began to precipitate
almost immediately. The mixture was allowed to stand
for 30 min at room temperature, then the solid was
filtered off and washed with Et2O (5 cm3) and air-dried
as [{Cu(NO2)(tpmsal)}2] 4 (0.283 g, 80%). IR (Nujol
4. Experimental
4.1. Synthesis
Commercially available reagents and solvents were
purchased from standard suppliers. Acetonitrile was
distilled from CaH2 under N2 before use. Infrared (400Á
/
mull): 1606s (CÄ
/
N), 1583m, 1569m, 1532m, 1378s
5000 cmꢂ1, Nujol mulls) and UVÁ
/
Vis (200Á800 nm)
/
(NO2), 1149m (NO2), 1105m, 1041m, 759s, 662m and
556m cmꢂ1. UV (MeCN): 605 (o 328), 382 (o 18400) and
269 nm (o 73000).
spectra were recorded using Shimadzu FTIR-8300 and
UV-2101 PC spectrophotometers respectively. Solution
conductivities were obtained using a Portland Electronic
conductivity meter. Microanalyses were determined by
Mr. A. Saunders (University of East Anglia).
4.6. Preparation of [{Cu(NO2)(tpms)}n] (5)
tpmsH (0.20 g, 0.55 mmol) was dissolved in a mixture
of EtOH (15 cm3) plus water (5 cm3). A solution of
[Cu2(OAc)4(H2O)2] (0.11 g, 0.28 mmol) in water (5 cm3)
was added and the solution was stirred for 10 min.
Aqueous NaNO2 (0.084 g, 1.21 mmol) was added, and
the green solution was stirred for 5 h. The resulting
precipitate was filtered off, washed with EtOH, and
4.2. Preparation of [Cu(NO2)2(tpml)] (1)
A solution of CuSO4×
/
5H2O (0.11 g, 0.45 mmol) plus
NaNO2 (0.1 g, 1.5 mmol) in water (5 cm3) was added to
a stirred solution of tpml (0.2 g, 0.45 mmol) in EtOH (20
cm3). The mixture was stirred for 20 min, then filtered;

148
P.J. Arnold et al. / Inorganica Chimica Acta 348 (2003) 143Á149
/
dried in vacuo as [{Cu(NO2)(tpms)}n]×
/
nH2O 4 (0.23 g,
ferred to an EnrafÁNonius CAD4 diffractometer (with
monochromated Mo Ka radiation), at room tempera-
ture, for determination of accurate cell parameters (from
/
87%). IR (KBr disc): 3526m, 3452m, 3304m, 1690s
(amide I), 1612s (CO2), 1535m, 1466m, 1441m, 1396m,
1383m (NO2), 1275m, 1196w, 1121s, 1024w, 876w,
787m, 779m, 756m, 662m, 586w and 436w cmꢂ1. UV
the settings of 24 reflections, uꢀ
/
10Á118, each centred in
/
four orientations) and measurement of diffraction
intensities. During processing, corrections were applied
for Lorentz-polarisation effects, slight crystal deteriora-
tion, absorption (by semi-empirical c-scan methods)
and to eliminate negative net intensities (by Bayesian
statistical methods). The structure was determined by
the direct methods routines in the SHELXS program [7]
and refined by full-matrix least-squares methods, on F2
values, in SHELXL [8]. The Cu atom and all the non-
hydrogen atoms in the tpmbz ligand were refined with
anisotropic thermal parameters; the Uiso values of the
hydrogen atoms, included in idealised positions, were
also refined freely. There is disorder in both the nitro
(MeCNꢁ20%H2O): 644 (o 35), 361sh (o 250) and 266
nm (o 16400).
/
4.7. Crystal structure analyses
The crystal structure analysis of [Cu(NO2)2(tpmbz)] 3,
is described here; the procedures for the other complexes
were similar. Crystallographic and refinement data for
the three complexes are collected in Table 3.
Crystals of 3 were dark green needles. One, ca. 0.46ꢃ
/
0.11ꢃ
/
0.10 mm3, was mounted on a glass fibre. After
preliminary photographic examination, this was trans-
Table 3
Crystal and structure refinement data for complexes, 3, 4 and 5
Complex
[Cu(NO2)2(tpmbz)] (3)
[{Cu(NO2)(tpmsal)}2]×
/
Et2O
[{Cu(NO2)(tpms)}n ]×
/
nH2O
(4)
(5)
Elemental formula
Formula weight
Crystal system
C23H18CuN6O4
506.0
C46H34Cu2N10O6×
/
C4H10
O
C20H17CuN5O5×
/H2O
1024.0
monoclinic
P21/n (equiv. to no. 14)
488.9
orthorhombic
Pbca (no. 61)
monoclinic
P21/c (no. 14)
Space group
Unit cell dimensions
˚
a (A)
13.937(2)
9.0701(9)
13.326(6)
10.980(6)
16.656(12)
90
14.5745(13)
17.292(2)
15.456(2)
90
˚
b (A)
˚
c (A)
18.560(2)
90
a (8)
b (8)
g (8)
109.495(9)
90
2211.6(4)
111.28(5)
90
90
90
3
˚
V (A )
Z
2271(2)
2
1.50
3895.2(7)
8
4
1.520
Dcalc (Mg mꢂ3
F(000)
)
1.668
2008
1.174
1036
1.03
1056
1.00
Absorption coefficient (mmꢂ1
Crystal colour, shape
)
dark emerald green needles
dark green translucent prisms deep blue and turquoise
prisms
Crystal size (mm3)
0.46ꢃ
1.5Á27.0
1/17, ꢂ
1.7
0.998 and 0.978
/
0.11ꢃ
/
0.10
0.33ꢃ
1.5Á24.0
1/15, ꢂ
4.3
/
0.24ꢃ
/
0.21
0.31ꢃ/0.17ꢃ0.14
/
u Range for data collection (8)
Index ranges for h, k, l
/
/
2.2Á27.0
/
ꢂ/
/
1/11, ꢂ
/23/23
ꢂ
/
/1/12, ꢂ19/19
/
0/18, 0/22, 0/19
0
Crystal degradation (%)
Max. and min. transmission
0.256 and 0.181
3760
0.15 and 0.13
4232
Total no. of reflections measured (not including 5387
absences)
Rint for equivalents
0.013
0.073
Total no. of unique reflections
4817
2502
3554 (2780 to umax
1520 (1411 to umax
direct methods
ꢀ
ꢀ/
/
228)
228)
4232
2610
No. of observed reflections (I ꢀ
Structure determined by
/
2s(I))
direct methods
automated Patterson
methods
4232/0/378
1.019
Data/restraints/parameters
Goodness-of-fit on F2, S
Final R indices (observed data)
Final R indices (all data)
Reflections weighted a
4817/0/333
1.073
2780/0/322
1.006
R1ꢀ
R1ꢀ
wꢀ
[s2(Fo2)ꢁ
0.43 and ꢂ0.41
/
0.049, wR2ꢀ
/
0.111
R1ꢀ
R1ꢀ
wꢀ
[s2(Fo2)ꢁ
0.83 and ꢂ1.29
close to the Cu atom
/
0.086, wR2ꢀ
/
0.209
R1ꢀ
R1ꢀ
[s2(Fo2)ꢁ
0.54 and ꢂ0.50
close to Cu atom
/0.043, wR2ꢀ
/
0.095
0.117
/
0.102, wR2ꢀ
/0.140
/
0.142, wR2ꢀ
/0.274
/
0.078, wR2ꢀ
/
/
/
(0.0554P)2]ꢂ1 a
/
/
(0.1660P)2]ꢂ1 wꢀ
/
/
(0.0515P)2]ꢂ1
ꢂ3
˚
Largest difference peak and hole (e A
Location of largest difference peak
)
/
/
/
amongst the disordered NO2
groups
a
Where Pꢀ
/
(Fo2ꢁ2Fc2)/3.
/

P.J. Arnold et al. / Inorganica Chimica Acta 348 (2003) 143Á
/
149
149
Griffiths, D.L. Hughes, R.L. Richards, P.C. Sharpe, J. Chem.
Soc., Dalton Trans. (2001) 736.
groups; some atoms in these ligands were refined with
partial occupancies and isotropic thermal parameters.
Scattering factors for neutral atoms were taken from
Ref. [9]. Computer programs used in this analysis have
been noted above or in Ref. [10], Table 4, and were run
on a DEC-AlphaStation 200 4/100 in the Nitrogen
Fixation Laboratory, John Innes Centre.
In the analysis of complex 4, an unresolved region of
electron density about a centre of symmetry in the
crystal is believed to result from disordered solvent
molecules, probably diethyl ether; seven peaks were
included in the refinement as carbon part-atoms.
[2] (a) S. Suzuki, K. Kataoka, K. Yamaguchi, Acc. Chem. Res. 33
(2000) 728;
(b) M.E.P. Murphy, S. Turley, E.T. Adman, J. Biol. Chem. 272
(1997) 28455;
(c) F.E. Dodd, J. Van Beeumen, R.R. Eady, S.S. Hasnain, J. Mol.
Biol. 282 (1998) 369;
(d) T. Inoue, M. Gotowda, Deligeer, M. Kataoka, K. Yamaguchi,
S. Suzuki, H. Watanabe, M. Gohow, Y. Kai, J. Biochem. 124
(1998) 876.;
(e) M.J. Boulanger, M. Kukimoto, M. Nishiyama, S. Horinouchi,
M.E.P. Murphy, J. Biol. Chem. 275 (2000) 23957.
[3] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, Part B: Applications in Coordination,
Organometallic and Bioinorganic Chemistry, 5th ed., Wiley, New
York, 1997, pp. 48Á53.
/
Acknowledgements
[4] F. Jiang, R.C. Conry, L. Bubacco, Z. Tyekla´r, R.R.
Jacobson, K.D. Karlin, J. Peisach, J. Am. Chem. Soc. 115
(1993) 2093.
We thank the BBSRC for financial support for this
work, and EPSRC for a ROPA award (to support
P.C.S. and P.J.A.).
[5] N. Komeda, H. Nagao, Y. Kushi, G. Adachi, M. Suzuki, A.
Uehara, K. Tanaka, Bull. Chem. Soc. Jpn. 68 (1995) 581.
[6] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
[7] G.M. Sheldrick, Acta Crystallogr., A 46 (1990) 467.
[8] G.M. Sheldrick, SHELXL, Program for Crystal Structure Refine-
References
ment, University of Gottingen, Gottingen, Germany, 1993.
¨ ¨
[9] A.J.C. Wilson (Ed.), International Tables for X-ray Crystal-
lography, vol. C, Kluwer Academic Publishers, Dordrecht, 1992,
pp. 193, 219 and 500.
[1] (a) P.J. Arnold, S.C. Davies, J.R. Dilworth, M.C. Durrant, D.V.
Griffiths, D.L. Hughes, R.L. Richards, Inorg. Chem. Comm. 1
(1998) 43;
[10] S.N. Anderson, R.L. Richards, D.L. Hughes, J. Chem. Soc.,
Dalton Trans. (1986) 245.
(b) P.J. Arnold, S.C. Davies, J.R. Dilworth, M.C. Durrant, D.V.