Tricarbonylrhenium(I) bromide complexes with diimine ligands: Structural, electrochemical, and spectroscopic studies

Article abstract of DOI:10.1080/15533174.2012.680160

Four rhenium(I) complexes, [Re(CO)₃Br(Lⁿ)] (n = 1-4), [Lⁿ = (4-fluorophenyl)pyridin-2-ylmethyleneamine (L¹), (4-chlorophe nyl)pyridin-2-ylmethyleneamine (L²), (4-bromophenyl)pyridin-2-ylmethyleneamine (L³), and (4-iodophenyl)pyridin-2-ylmethylenea mine, (L⁴)] have been synthesized and characterized by CHN analyses, ¹H, ¹³C-NMR, IR, and UV-vis spectroscopy. The molecular structure of [Re(CO)₃Br(L¹)] is a distorted octahedron around rhenium with one Br, facial arrangement of three COs, and one diimine. UV-vis absorption and emission properties of the complexes have been studied at room temperature and the redox potentials are approximately insensitive to the substituent on the phenyl ring of ligands.

Full text of DOI:10.1080/15533174.2012.680160

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Tricarbonylrhenium(I) Bromide Complexes With
Diimine Ligands: Structural, Electrochemical, and
Spectroscopic Studies
Saeed Dehghanpour a & Roghayeh Aleesha a
a Department of Chemistry , Alzahra University , Tehran , I. R. Iran
Accepted author version posted online: 21 Jun 2012.Published online: 28 Aug 2012.
To cite this article: Saeed Dehghanpour & Roghayeh Aleesha (2012) Tricarbonylrhenium(I) Bromide Complexes With Diimine
Ligands: Structural, Electrochemical, and Spectroscopic Studies, Synthesis and Reactivity in Inorganic, Metal-Organic, and
Nano-Metal Chemistry, 42:8, 1132-1138, DOI: 10.1080/15533174.2012.680160
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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 42:1132–1138, 2012
Copyright ꢀ Taylor & Francis Group, LLC
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ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2012.680160
Tricarbonylrhenium(I) Bromide Complexes
With Diimine Ligands: Structural, Electrochemical,
and Spectroscopic Studies
Saeed Dehghanpour and Roghayeh Aleesha
Department of Chemistry, Alzahra University, Tehran, I. R. Iran
According to this view, we herein describe the synthesis, prop-
Four rhenium(I) complexes, [Re(CO)3Br(Ln)] (n = 1–4), [Ln =
(4-fluorophenyl)pyridin-2-ylmethyleneamine (L1), (4-chlorophe
nyl)pyridin-2-ylmethyleneamine (L2), (4-bromophenyl)pyridin-2-
ylmethyleneamine (L3), and (4-iodophenyl)pyridin-2-ylmethylenea
mine, (L4)] have been synthesized and characterized by CHN anal-
erties, and structural characterization of Re(I) complexes of the
type [Re(CO)3BrL] in which L is an unsymmetrical bidentate
iminopyridine ligand (Scheme 1).
1
yses, H, 13C-NMR, IR, and UV-vis spectroscopy. The molecular
structure of [Re(CO)3Br(L1)] is a distorted octahedron around
rhenium with one Br, facial arrangement of three COs, and one di-
imine. UV-vis absorption and emission properties of the complexes
have been studied at room temperature and the redox potentials
are approximately insensitive to the substituent on the phenyl ring
of ligands.
Keywords bidentate diimine ligand, electrochemistry, emission, rhe-
nium complex, X-ray crystallography
INTRODUCTION
SCH. 1.
Tricarbonylrhenium(I) complexes of the type fac-[Re
(diimine)(CO)3L] (L = auxiliary monodentate ligand) have very
interesting properties such as relatively high thermal and pho-
tochemical stabilities, high redox potentials, and luminescence
in the visible region, which have led to their applications as
light switches,[1] ion sensors,[2] intercalating agents for nucleic
acids,[3] probes for biological molecules,[4] and models in funda-
mental studies of energy and electron-transfer reactions relevant
to solar energy conversion. Tuning the physicochemical prop-
erties of these complexes by changing the nature of the diimine
offers a high degree of versatility for the design of new systems,
which may perform useful, specific functions.[5] The majority
of research in this field has focused on the use of polypyridine
derivatives such as 2,2ꢁ-bipyridine and 1,10-phenanthroline as
ligands.[6–13] However, there are little data on complexes with
unsymmetrical diimine ligands containing iminopyridine.[14–21]
EXPERIMENTAL
General
All chemicals were of reagent grade and used as received.
Solvents were purified by literature methods.[22] Synthesis and
molecular structures of 2 and 3 have previously been re-
ported.[23,24] The ligands were prepared according to reported
procedures.[25] Elemental analyses were performed using a Her-
aeus CHN-O RAPID elemental analyzer (Alzahra University,
Iran). IR spectra were recorded on a Bruker Tensor 27 spec-
trophotometer (Alzahra University, Iran). Electronic absorption
spectra were recorded on a JASCO V-570 spectrophotometer
(Alzahra University, Iran); λmax (log ε). NMR spectra were ob-
tained on a BRUKER (250 MHz) spectrometer (Tarbiat Modares
University, Iran). Proton chemical shifts are reported in parts
per million (ppm) relative to an internal standard of Me4Si.
All voltammograms were recorded with a three-electrode sys-
tem consisting of an Ag/AgCl reference electrode, a platinum
wire counter electrode, and Au as a working electrode. A
Metrohm multipurpose instrument model 693 VA processor
with 694A VA stand was used (Alzahra University, Iran). Cyclic
Received 10 October 2011; accepted 24 March 2012.
S. Dehghanpour would like to acknowledge the Alzahra University
Research Council for partial support of this work.
Address correspondence to Saeed Dehgahanpour, Department of
Chemistry, Alzahra University, PO Box 1993891176, Tehran, I. R.
Iran. E-mail: Dehganpour farasha@yahoo.com
1132

TRICARBONYLRHENIUM(I) BROMIDE, DIIMINE LIGANDS
1
1133
ring). 13C-{ H} NMR (250 MHz, DMSO-d6)(: 197.9, 196.8,
186.7, 170.2, 154.9, 153.2, 150.1, 140.4, 138.2, 130.6, 129.8,
124.3, 96.1. For C15H9BrIN2O3Re, Anal Calcd. (%): C, 27.37;
H, 1.37; N, 4.26. Found (%): C, 27.30; H, 1.42; N, 4.20.
voltammograms were obtained in chloroform with 0.1M tetra-
butylammonium perchlorate (TBAClO4) as the supporting elec-
trolyte. In all electrochemical experiments the test solution was
purged with argon for at least 5 min. Emission spectra were
obtained using a Varian Cary Eclipse fluorescence spectropho-
tometer at room temperature (Alzahra University, Iran).
Crystal Structure Determination
Data were collected on a Bruker-Nonius Kappa-CCD diffrac-
tometer (University of Toronto, Canada) using monochromated
MoKα radiation and measured using a combination of ϕ scans
and ω scans with κ offsets to fill the Ewald sphere. The data were
processed using the Denzo-SMN package.[26] Absorption cor-
rections were carried out using SORTAV.[27] The structures were
solved and refined using SHELXTL V6.1 for full-matrix least-
squares refinement based on F2.[28] All H-atoms were included
in calculated positions and allowed to refine in a riding-motion
approximation with Uiso tied to the carrier atom.
Syntheses of the Complexes
Synthesis of Re(L1)(CO)3Br (1)
A mixture of [Re(CO)5Br] (406 mg, 1 mmol) and L1 (200 mg,
1 mmol) in dry, degassed toluene (30 cm3) was heated at reflux
for 4 h under N2 to give a bright red solution. The solvent
was removed at reduced pressure and the crude material recrys-
tallized from CH2Cl2/hexane to give Re(L1)(CO)3Br as pure
orange crystals. Yield: 89%. IR (cm−1, KBr): 2021, 1910, 1893
1
(C O, vs); 1584 (C N, s). H-NMR (250 MHz, DMSO-d6):
9.35 (s, 1H, H5), 9.13 (d, 1H, JHH = 5.50 Hz, H1), 8.38 (m, 2H,
H2, H4), 7.88 (m, 1H, H3), 7.62–7.74 (m, 4H, aromatic ring).
1
13C-{ H} NMR (250 MHz, DMSO-d6)(: 196.3, 195.9, 185.5,
RESULTS AND DISCUSSION
170.0, 154.8, 153.2, 140.4, 130.5, 129.7, 124.4, 124.2, 116.5,
116.1. For C15H9FBrN2O3Re, Anal. Calcd. (%): C, 32.73; H,
1.65; N, 5.09; Found (%): C, 32.74; H, 1.67; N, 4.99.
Synthesis
[Re(CO)3Br(Ln)] (n = 1–4) was prepared by the reaction of
the appropriate ligand with [Re(CO)5Br] in toluene and precip-
itated in analytically pure form. All complexes are soluble in
THF, dichloromethane, and chloroform solvents and insoluble
in ether and hexane. These complexes are stable in air in the
solid state for three weeks.
Synthesis of Re(L2)(CO)3Br (2)
This complex was prepared by a procedure similar to 1 using
216 mg (1 mmol) of L2.[26] Orange crystals were collected by
filtration and dried in vacuo. Yield: 91%. IR (cm−1, KBr): 2023,
1
1912, 1888 (C O, vs); 1583 (C N, s). H-NMR (250 MHz,
Structure of [Re(CO)3Br(L1)], 1
A view of 1 along with the atom-numbering scheme is shown
in Figure 1. The crystallographic data are summarized in Table 1
DMSO-d6)(: 9.33 (s, 1H, H5), 9.09 (d, 1H, JHH = 5.25 Hz,
H1), 8.36 (m, 2H, H2, H4), 7.84 (m, 1H, H3), 7.30–7.61 (s, 4H,
1
aromatic ring). 13C-{ H} NMR (250 MHz, DMSO-d6) (: 196.9,
196.4, 186.2, 170.5, 154.8, 153.2, 149.3, 140.4, 133.4, 130.6,
129.8, 129.4, 124.0. For C15H9ClBrN2O3Re, Anal. Calcd. (%):
C 31.79, H 1.59, N 4.94. Found (%): C 31.89, H 1.50, N 4.99.
Synthesis of Re(L3)(CO)3Br (3)
This complex was prepared by a procedure similar to 1 using
261 mg (1 mmol) of L3.[27] Orange crystals were collected by
filtration and dried in vacuo. Yield: 87%. IR (cm−1, KBr): 2025,
1
1914, 1886 (C O, vs); 1588 (C N, s). H-NMR (250 MHz,
DMSO-d6) (: 9.32 (s, 1H, H5), 9.09 (d, 1H, JHH = 5.25 Hz,
H1), 8.36 (m, 2H, H2, H4), 7.85 (m, 1H, H3), 7.37–7.68 (m, 4H,
1
aromatic ring). 13C-{ H} NMR (250 MHz, DMSO-d6) (: 197.3,
196.6, 186.4, 170.5, 154.8, 153.2, 149.7, 140.4, 132.4, 130.5,
129.8, 124.3, 121.9. For C15H9Br2N2O3Re Anal. Calcd. (%): C,
29.47; H, 1.48; N, 4.58. Found (%): C, 29.46; H, 1.46; N, 4.57.
Synthesis of Re(L4)(CO)3Br (4)
This complex was prepared by a procedure similar to 1 using
308 mg (1 mmol) of L4. Orange crystals were collected by
filtration and dried in vacuo. Yield: 88%. IR (cm−1, KBr): 2021,
1896 (C O, vs); 1581 (C N, s). 1H-NMR (250 MHz, DMSO-
d6)(: 9.32 (s, 1H, H5), 9.08 (d, 1H, JHH = 5.20 Hz, H1), 8.35
(m, 2H, H2, H4), 7.85 (m, 1H, H3), 7.31–7.65 (m, 4H, aromatic
FIG. 1. Structure of 1 in the crystal, showing the atom-labeling scheme. Ther-
mal ellipsoids with 50% probability.

1134
S. DEHGHANPOUR AND R. ALEESHA
TABLE 1
Crystal data and structure refinement for 1
TABLE 2
Selected bond lengths (Å) and bond angles (◦) for 1
Emprical formula
C15H9BrFN2O3Re
Re1-C2
1.916(5)
Re1-Br1
2.6113(7)
Formula weight
Temperature
Wavelength
Crystal system
Space group
a
b
c
550.35
150(1) K
0.71073 Å
Monoclinic
P 21/c
Re1-C1
Re1-C3
Re1-N1
Re1-N2
C2-Re1-C1
C2-Re1-C3
C1-Re1-C3
C2-Re1-N1
C1-Re1-N1
C3-Re1-N1
C2-Re1-N2
C1-Re1-N2
1.920 (7)
1.925 (6)
2.172 (5)
2.186 (5)
88.0 (3)
88.1 (3)
88.8 (3)
96.4 (2)
95.3 (3)
174.0 (2)
170.9 (2)
92.6 (3)
O1-C1
O-C2
O3-C3
1.143(6)
1.148 (5)
1.147 (6)
C3-Re1-N2
N1-Re1-N2
C2-Re1-Br1
C1-Re1-Br1
C3-Re1-Br1
N1-Re1-Br1
N2-Re1-Br1
101.0 (2)
74.59 (18)
93.25 (19)
178.7 (2)
90.82 (19)
84.97 (13)
86.31 (13)
8.9326(2) Å
25.5742(5) Å
6.9479(3) Å
108.9170(14)◦
1501.48(8) Å3
4
β
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
Crystal size
Theta range for data
collection
2.435 Mg/m3
10.780 mm–1
1024
for such complexes.[15,29] The rhenium–carbonyl bond lengths
do not show any significant differences [1.916(5) and 1.925(6)
Å] and are consistent with those observed in similar com-
plexes.[15,16,30]
0.08 × 0.05 × 0.02 mm3
2.89 to 27.48◦.
Index ranges
–8 ≤ h ≤ 11, –32 ≤ k ≤ 30,
–9 ≤ l ≤ 9
Despite the fact that the donor nitrogens are sp2-hybridized,
the chelate ring is significantly puckered in this complex and
some strain in the chelate ring is suggested by the deviation from
120◦ angle about the nitrogen, C4-N1-Re1 [126.0(4)◦], C8-N1-
Re1 [116.4(4)◦], C4-N1-C8 [117.7(5)◦]. The crystal packing in
the unit cell is shown in Figure 2. As shown in Figure 2, the
phenyl rings of the ligands are on one side and are approximately
parallel to each other. Therefore, there is partial overlapping be-
tween these moieties with a nearest distance of 3.53 Å between
the parallel the planes. Structure of complex 1 is similar to
complexes 2 and 4, as reported previously.[23,24] No significant
changes are observed in the bond length, bond angles, and di-
hedral angles in these complexes (Table 3), which is consistent
of with absorption, emission, and redox properties.
Reflections collected
Independent reflections
Completeness to theta =
25.00◦
Absorption correction
Max. and min.
10161
3402 [R(int) = 0.0473]
99.8%
Semiempirical from equivalents
0.805 and 0.614
transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices
[I>2sigma(I)]
R indices (all data)
Largest diff. peak and hole 2.747 and –1.979 e.Å–3
Full-matrix least-squares on F2
3402/3/213
1.054
R1 = 0.0376, wR2 = 0.0843
R1 = 0.0522, wR2 = 0.0912
TABLE 3
Comparison of bond lengths and dihedral angles of the
pyridine, chelate, and benzene ring in compounds 1, 2, and 4
and selected bond distances and angles are given in Table 2.
Compound 1 crystallizes in the monoclinic space group P21/c.
The geometry of rhenium atom can be best described as distorted
octahedral defined by one bromide, three facial carbonyls, and
the diimine ligand (L1). The steric requirements of the bidentate
ligand causes distortion of the octahedral coordination, clearly
seen by bite angles [N1–Re1–N2, 74.59(18)◦] (Table 2). Trans
angles at ReI are in the 170.9(2)–178.7(2)◦ range, also showing
a deviation from an ideal octahedral arrangement. The axially
disposed bromo and carbonyl ligands are disordered over two
positions with the refined site occupancy factors of about 0.92
and 0.08. The coordinated bromide is slightly tilted toward the
diimine ligand, causing a narrowing of the N–Re–Br angles
[84.97(13)◦ for N1-Re1-Br1, 86.31(13)◦ for N2-Re1-Br1]. The
Re–N bond lengths are similar and within the range expected
1
2a
4a
Re-Nave [Å]
Re-Cave [Å]
Re-Br [Å]
2.179 2.176 2.183
1.920 1.941 1.924
2.611 2.616 2.614
1.456 1.248 1.638
Dihedral angle (◦) between planes
of pyridine ring and chelate ring
Dihedral angle (◦) between planes
of chelate ring and benzene ring
Dihedral angle (◦) between planes
of pyridine ring and benzene ring
Torsion angle (◦) N-C-C-N
41.200 45.092 42.884
40.433 46.193 42.615
1.378 –2.852 –1.338
aData from Otwinowski and Minor[26] and Blessing.[27]

TRICARBONYLRHENIUM(I) BROMIDE, DIIMINE LIGANDS
1135
FIG. 2. Crystal packing in the unit cell for 1.
IR Spectra
The IR spectra of complexes recorded in KBr pellets dis-
assigned based on the splitting of the resonance signals, spin
coupling constants, literature data and in accordance with the
molecular structure determined by the X-ray crystal structure
analysis. The 1H resonances of the coordinated ligands are ob-
served in complexes 1–4. Aside from the aromatic H-atoms,
which appear at 7.24–9.13 ppm, the imine protons appear as a
singlet at 9.32–9.35 ppm. The downfield shift of the imine pro-
tons relative to the free ligands can be attributed to the deshield-
ing effect resulting from the coordination of the metal by the
ligands.[32–34] 13C NMR spectra show that carbon atoms of the
complexes 1–4 appear at 116–197 ppm. For the complexes, the
signals due to the diimine ligands appear at 116–170 ppm and
in keeping with the fac arrangement of the CO ligands, the
played three metal carbonyl bands in the 2025–1886 cm−1 re-
gion (Table 4). This is consistent with Cs symmetry for the
compounds with two α1 bands and an αꢁꢁ band. Under the
conditions of the measurement, the latter bands are clearly sep-
arated in 1, 2, and 3, but the two bands were overlapped in
complex 4. This complex shows two peaks in this region.[29]
The wavenumbers of the CO stretches are very sensitive to the
dπ electron density (oxidation state) of the rhenium center. The
constancy of the wave numbers among the complexes, as ob-
served in Experimental section, indicates that the ligands induce
an equivalent perturbation on the metal center. The IR spectra of
complexes also show strong bands in the 1588–1581 cm−1 re-
gion corresponding to the azomethine (C N). These bands shift
to lower wavenumbers relative to ligands (1629–1631 cm−1
for the ligands). The observed shift in C N stretch after
complexation confirms the coordination of the azomethine
(C N).[25,31]
1
13C{ H} NMR spectra show three low-field signals assignable
to the CO groups.
Absorption and Emission Properties
The electronic spectra of the complexes were recorded in the
700–200 nm range. The spectral data are presented in Table 4.
The uncoordinated ligands are completely transparent above
1H, 13C-NMR Spectra
The peak assignments for the 1H NMR spectra are presented 335 nm.[24] The absorption spectra of all the complexes exhibit a
in the Experimental section for each complex. These peaks are broad band close to 451 nm. This lowest energy feature in each
TABLE 4
Absorption, florescence, and electrochemical properties of BrRe(CO)3L complexes
Cyclic
voltammetry
Ep(V)a
Absorption UV-Vis λmax(nm)
(log ε/M−1cm−1
Emissiona
λmax(nm)
)
Complex
(solvent = CHCl3)
IR IR (cm–1, KBr)
1
2
3
4
1.51
1.53
1.52
1.49
643
649
639
637
452 (3.39), 332 (3.78), 242 (4.19)
451 (3.59), 331 (4.04), 242 (4.39)
451 (3.62), 337 (4.06), 242 (4.38)
451 (3.41), 351 (3.85), 242 (4.32)
2021, 1910, 1893 (C O); 1584 (C N)
2023, 1912, 1888 (C O); 1583 (C N)
2025, 1914, 1886 (C O); 1588 (C N)
2021, 1896 (C O); 1581 (C N)
aRecorded in aerated CHCl3 at 298 K. Excited at 452 nm (1), 451 nm (2), 451 nm (3), and 451 nm (4).

1136
S. DEHGHANPOUR AND R. ALEESHA
TABLE 5
Solvent dependence of MLCTaAbsorption at 289 K
Complex
UV-vis λmax (nm) (log ε/M−1cm−1
)
Solvent
1
1
1
1
2
2
2
2
3
3
3
3
4
4
4
4
408 (3.47)
422 (3.65)
437 (3.31)
452 (3.38)
414 (3.58)
424 (3.21)
444 (4.06)
451 (3.58)
406 (3.62)
415 (3.07)
443 (3.28)
451 (3.62)
410 (3.70)
415 (3.35)
443 (3.55)
451 (3.41)
DMSO
CH3CN
CH2Cl2
CHCl3
DMSO
CH3CN
CH2Cl2
CHCl3
DMSO
CH3CN
CH2Cl2
CHCl3
DMSO
CH3CN
CH2Cl2
CHCl3
FIG. 4. Cyclic voltammograms of 1 in CHCl3 at 50 and c = 3 × 10–3, (a) 100,
(b) 200, (c) 300, (d) 400, (e) 500 mVs–1
.
Excitation of the complexes at 451–452 nm leads to the obser-
vation of the emission bands at 637–649 nm (Table 4, Figure 3).
With reference to previous spectroscopic studies on other sim-
ilar rhenium(I) complexes,[40–44] the emission was assigned as
derived from excited states of a 3MLCT origin. Consistent with
the UV-vis absorption spectra, the emission bands are approxi-
mately insensitive to the substituent on the phenyl ring of ligands
in the complexes 1–4.
case is the metal-to-ligand [Re(dπ)-ligand(π∗) MLCT tran-
sition] charge transfer transition.[14,35–39] Other higher energy
bands are observed, which are due to intraligand transitions.
However, position of the low-energy MLCT absorption band, is
approximately insensitive to the substituent on the phenyl ring
of ligands but this band, for complexes (1–4), is quite sensitive
to solvent. The absorption maximum blue-shifts with increased
solvent polarity (Table 5). Similar effects have been reported for
MLCT absorptions of bipyridine and phenanthroline complexes
of rhenium.[14–21,33,34]
1
Electrochemistry
The electrochemical behavior of the complexes was exam-
ined by means of cyclic voltammetry in CHCl3 and is presented
in Table 4. The Four ligands are electroinactive in the working
potential region. A typical cyclic voltammogram of 1 is shown
in Figure 4. An irreversible oxidation is observed in the anodic
region for complexes 1–4 at about 1.50 V versus SCE, which
can be assigned to Re+ → Re2+ [14–16,45]
.
The corresponding
cathodic peak was not observed, however, even under fast-scan-
rate conditions (Figure 4). No significant changes are observed
with variation of the ligands in the oxidation wave of the com-
plexes.
CONCLUSION
Four rhenium complexes, [Re(CO)3Br(Ln)] [Ln = (4-fluoro-
phenyl)pyridin-2-ylmethyleneamine (1), (4-chlorophenyl)
pyridin-2-ylmethyleneamine (2), (4-bromophenyl)pyridin-2-
ylmethyleneamine (3), (4-iodophenyl)pyridin-2-ylmethylenea
mine (4)] have been synthesized. The crystal structure of 1
revealed that the coordination geometry of the rhenium atom
could be best described as distorted octahedral geometry de-
fined by one bromide, facial arrangement of three-coordinated
carbonyls, and the diimine ligand (L). All of these complexes
exhibit low-energy absorption bands at about 451 nm, corre-
sponding to a MLCT transition. Excitation of the complexes
at 451–452 nm leads to the observation of the emission bands
at 637–649 nm. An irreversible oxidation is observed in the
anodic region for complexes 1–4 at about 1.50 V. However,
the potentials and absorption bands are insensitive to the
substituent on the phenyl ring of the iminopyridine ligands.
FIG. 3. Emission spectrum of 2 in CHCl3 at 25◦C.

TRICARBONYLRHENIUM(I) BROMIDE, DIIMINE LIGANDS
1137
SUPPLEMENTARY MATERIALS
15. Czerwieniec, R.; Kapturkiewicz, A.; Lipkowski, J.; Nowacki, J.
Re(I)(tricarbonyl)(+) complexes with the 2-(2-pyridyl)-N-methyl-
benzimidazole, 2-(2-pyridyl)benzoxazole and 2-(2-pyridyl)benzothiazole
ligands - syntheses, structures, electrochemical and spectroscopic studies.
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Crystallographic data for compound 1 are given in Table
1. The crystallographic data for 1 have been deposited with
the Cambridge Crystallographic Data Centre as supplemen-
tary publication No. CCDC 798904. The copies of these data
can be obtained free of charge via http://www.ccdc.cam.ac.uk/
data request/cif, by emailing data request@ccdc.cam.ac.uk
or by contacting The Cambridge Crystallographic Data Cen-
tre, 12 Union Road, Cambridge CB2 1EZ, UK (Fax: +44 1223
336033).
17. Dinda, J.; Sinha, C. Naphthyl-(2-pyridylmethylene)amine complexes of
silver(I) and ruthenium(II): synthesis, spectral studies and electrochemical
behavior. Transition Met. Chem. 2003, 28, 864–870.
18. Zhang, J.; Li, W.; Bu, W.; Wu, L.; Ye, L.; Yang, G. The homochiral met-
allosupramolecular column structure of rhenium(I) complex. Inorg. Chim.
Acta 2005, 358, 964–970.
19. Nickolacheva, L.G.; Vogels, C.M.; Stefan, R.A.; Warwish, H.A.; Duffy,
S.J.; Ireland, R.J.; Decken, A.; Hudson, R.H.; Westcott, S.A. Synthesis and
in vitro reactivity of cis-dichloro-(pyridin-2-ylcarboxaldimine)platinum(II)
complexes with DNA. Can. J. Chem. 2003, 81, 269–274.
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