Synthesis and structural studies of diamagnetic first-row transition metal complexes with the rigid nitrogen ligand: Bis[N-(2,6-diisopropylphenyl)imino]acenaphthene

Article abstract of DOI:10.1016/S0020-1693(02)00943-X

Reported are the syntheses and characterization of diamagnetic copper(I) and iron(II) complexes with the bidentate nitrogen ligand bis[N-(2,6-diisopropylphenyl)imino]acenaphthene (o,o′-iPr₂C₆H₃-BIAN). Namely, they are [Cu(

Full text of DOI:10.1016/S0020-1693(02)00943-X

Inorganica Chimica Acta 339 (2002) 209ꢁ214
/
www.elsevier.com/locate/ica
Synthesis and structural studies of diamagnetic first-row transition
metal complexes with the rigid nitrogen ligand:
bis[N-(2,6-diisopropylphenyl)imino]acenaphthene
Adriana Paulovicova a, Usama El-Ayaan a, Kayoko Umezawa a, Champika Vithana b,
Yuji Ohashi b, Yutaka Fukuda a,*
a Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
b Department of Chemistry and Materials Science, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama,
Meguro-ku, Tokyo 152-8550, Japan
Received 7 November 2001; accepted 6 February 2002
Dedicated to Professor Helmut Sigel on the occasion of his 65th birthday.
Abstract
Reported are the syntheses and characterization of diamagnetic copper(I) and iron(II) complexes with the bidentate nitrogen
ligand bis[N-(2,6-diisopropylphenyl)imino]acenaphthene (o,o?-iPr2C6H3-BIAN). Namely, they are [Cu(o,o?-iPr2C6H3-
BIAN)2](ClO4)(AcOH) (1), and [Fe(bipy)2(o,o?-iPr2C6H3-BIAN)](ClO4)2 (2), where bipyꢀ
/
2,2?-bipyridine, AcOHꢀacetic acid.
/
Moreover, the crystal structure of the novel dimeric Cu(I) compound with the p-brominated derivative of the o,o?-iPr2C6H3-BIAN
ligand, is also discussed. In [CuBr(o,o?-iPr2-p-BrC6H2-BIAN)]2 (3), the respective Cu(I) ion is in four-coordinate environment
tetrahedrally surrounded by two imine nitrogen atoms of o,o?-iPr2-p-BrC6H2-BIAN, and by two bridging bromide atoms.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: N-ligands; X-ray structures; Mixed-ligand complexes; Diamagnetic
1. Introduction
extensive synthetic work has also been reported. This
includes novel complexes of the [Pd(Me)(p-An-
Mixed ligand complexes are observed in biological
systems or in the intermediate chemical reactions with
metal ions, which is important to understand the
respective chemistry. Sigel’s investigations concerning
diimine and nucleoside mixed ligand chelate systems
have a great help toward understanding the driving
forces that led to the formation of such mixed-ligand
BIAN)(L-L)]SO3CF3 type [7] [L-Lꢀ
acenaphthene (p-An-BIAN), 1,10-phenanthroline
/
bis(anisylimino)-
(phen), 2,9-dimethyl-1,10-phenanthroline (dmphen),
1,2-bis(diphenylphosphino)ethane (dppe), and 1,3-
bis(diphenylphosphino)propane (dppp)], where, the p-
An-BIAN ligand and a second L-L ligand are coordi-
nated in a bidentate and unidentate fashion, respec-
tively. Other interesting examples include the zero valent
palladium and platinum [M(Ar-BIAN)(alkene)] com-
plexes [8] with the bidentate Ar-BIAN or bis(phenyli-
mino)camphane ligands obtainable only with electron
poor alkenes, such as dimethyl fumarate, fumaronitrile,
maleic anhydride, and tetracyanoethylene.
complexes [1ꢁ3]. In the context of the ongoing industrial
/
application of second- and third-row transition metal
systems, for example, of rhodium, palladium and
platinum, in catalytic processes [4], much interest has
been focused on these metal complexes containing bulky
rigid diimine ligands, such as bis(N-arylimino)ace-
naphthene (Ar-BIAN) [5,6]. Along with this research,
Except those systems with Ar-BIAN already men-
tioned above, up to now, only some rhenium complexes
were reported [9]. Recently, first two copper(II) mixed-
ligand complexes, namely [Cu(acac)(AcOH)(o,o?-
* Corresponding author. Fax: ꢂ
/
81-3-5978 5291.
E-mail address: fukuda@cc.ocha.ac.jp (Y. Fukuda).
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 0 9 4 3 - X

210
A. Paulovicova et al. / Inorganica Chimica Acta 339 (2002) 209ꢁ214
/
iPr2C6H3-BIAN)]ClO4
iPr2C6H3-BIAN)] (where acacꢀ
and
[Cu(AcOH)Cl2(o,o?-
acetylacetonate) were
The ferrocene/ferrocenium couple served as an internal
standard. The half wave potential (E1/2) was calculated
using the formula: E1/2 (EpaꢂEpc)/2, where, Epa and
Epc are the peak anodic and peak cathodic potentials,
respectively.
/
prepared and characterized in our laboratory [10]. Thus,
in the present work, a further study on this field
encompassing copper and iron transition metals and
giving details of the spectroscopic, magnetic and struc-
tural features is presented. Here, we report the syntheses
and characterization of some more copper and iron
complexes, [Cu(o,o?-iPr2C6H3-BIAN)2](ClO4)(AcOH)2
(1), and [Fe(bipy)2(o,o?-iPr2C6H3-BIAN)](ClO4)2 (2).
The X-ray crystal structure of the dimeric Cu(I) species
with the p-brominated Ar-BIAN ligand, [CuBr(o,o?-
iPr2-p-BrC6H2-BIAN)]2 (3), is discussed and compared
with those previously reported [10].
ꢀ
/
/
2.2. Synthesis of [Cu(o,o?-iPr2C6H3-
BIAN)2](ClO4)(AcOH)2 (1)
Both 0.13 g (3.51ꢄ
and 0.35 g (7.02ꢄ
10ꢃ4 mol) of o,o?-iPr2C6H3-BIAN
were combined and 40 ml of acetic acid was added.
After 2 h stirring at r.t., the redꢁbrown product was
/
10ꢃ4 mol) of Cu(ClO4)2 6H2O
/
/
filtered, washed quickly with dichloromethane and dried
in vacuum, yielding 58% of 1. C76H88ClN4O8Cu
(1284.5): Calc. C, 71.06; H, 6.91; N, 4.36. Found: C,
2. Experimental
1
71.04; H, 6.86; N, 4.59%. meff (24 8C): diamagnetic. H
2.1. Material and instrumentation
NMR (CD2Cl2, 300.40 MHz, 24 8C): dꢀ1.05 (d, H20),
/
1.27 (d, H21), 2.97 (sept, H19), 6.97 (d, H4), 7.43 (s,
H15?, H16?, H17?), 7.45 (s, H15, H16, H17), 7.52 (pst,
H5), 7.64 (pst, H5), 8.30 (d, H6). 13C NMR (CD2Cl2,
All starting materials were purchased from Wako
Pure Chemical Industries Ltd, and used without further
purification. The o,o?-iPr2C6H3-BIAN ligand was
synthesized from acenaphthenequinone and 2,6-diiso-
propylaniline [10].
300.40 MHz, 24 8C): dꢀ23.5, 23.1 (C20, C21), 29.7
/
(C19), 125.1 (C15, C17), 125.5 (C4), 129.2 (C5), 129.9
(C6), 131.6 (C7), 139.2 (C14, C18), 144.9 (C12), 163.2
(C1).
Elemental analyses (C, H, N) were performed on a
PerkinꢁElmer 2400 Series II CHNSIO Analyzer. Elec-
/
tronic spectra were recorded on an UV-3100PC Shi-
madzu spectrophotometer using 10 mm quartz cells at
room temperature (r.t.). Powder reflectance spectra were
obtained using the same instrument equipped with an
integrating sphere and using BaSO4 as a reference.
2.3. Synthesis of [Fe(bipy)2(o,o?-iPr2C6H3-
BIAN)](ClO4)2 (2)
Infrared spectra were recorded on a Perkinꢁ
IR Spectrometer Spectrum 2000 as KBr pellets and as
Nujol mulls in the 4000ꢁ
370 cmꢃ1 spectral range.
/
Elmer FT
A
mixture of 0.27
g
(7.44ꢄ
/
10ꢃ4 mol) of
10ꢃ4 mol) of
Fe(II)(ClO4)2 6H2O, and 0.37 g (7.39ꢄ
o,o?-iPr2C6H3-BIAN in 40 ml of acetic acid was stirred
for 15 min. To the red solid which formed soon from the
/
/
Magnetic susceptibilities were measured at r.t. on a
Shimadzu MB-100 Torsion Magnetometer. Diamag-
netic corrections were calculated using Pascal’s con-
redꢁ
bipyridine was added directly. After 6 h stirring at r.t.,
the resulting redꢁbrown solid product was filtered,
/
brown solution, 0.23 g (1.48ꢄ
10ꢃ3 mol) of 2,2?-
/
1
stants [11]. H and 13C NMR measurements at 24, 8C
/
were run on a JEOL JNM LA 300 WB spectrometer at
300.40 and 75.45 MHz, respectively, using a 5 mm probe
head in CD2Cl2 and CDCl3 solvents. Chemical shifts are
given in ppm relative to internal tetramethylsilane
washed quickly with dichloromethane and dried in
vacuum, yielding 48% of 2. C56H56Cl2N6O8Fe
(1067.8): Calc. C, 62.98; H, 5.29; N, 7.87. Found: C,
62.70; H, 5.32; N, 7.96%. IR (bipy): 1575, 1607 cmꢃ1
.
1
(TMS). A typical pulse width was 6.25 ms for H and
meff (24 8C): diamagnetic. 1H NMR (CD2Cl2, 300.40
MHz, 24 8C): dꢀ1.00 (d, H20), 1.21 (d, H21), 2.97
4.25 ms for 13C NMR measurements, respectively.
Thermogravimetric measurements were performed on
a DTG-50 Shimadzu Instrument. Electrochemical me-
asurements were recorded on a BAS 100BW electro-
/
(sept, H19), 6.67 (d, H4), 7.28 (s, H15, H16, H17), 7.37
(pst, H5), 7.42 (d, bipy), 7.49 (pst, bipy), 7.90 (d, H6),
8.12 (pst, bipy), 8.48 (d, bipy). 13C NMR (CD2Cl2,
chemical analyzer at r.t. with a scan rate of 100 mV sꢃ1
.
300.40 MHz, 24 8C): dꢀ23.1, 23.2 (C20, C21), 29.1
/
The solutions (1,2-dichloroethane (DCE), acetonitrile
(ACN), and acetone (ACO)) contained 1 mM (where
(C19), 123.5 (C16), 123.9 (C15, C17), 124.6 (C4), 128.3
(C5), 129.2 (C6), 130.0 (C3), 131.6 (C7), 135.5 (C14,18),
139.4 (bipy), 141.2 (C12), 148.0 (C13), 154.5 (bipy),
159.3 (bipy), 161.1 (C1).
(Caution! Perchlorate salts of metal complexes with
organic ligands are potentially explosive.)
Mꢀ
mol dmꢃ3) of the respective complex and tetra-
/
butylammonium perchlorate (0.1 M) as supporting
electrolyte. A three-electrode configuration composed
of a carbon working electrode, a platinum auxiliary
electrode and a Ag/AgCl reference electrode was used.

A. Paulovicova et al. / Inorganica Chimica Acta 339 (2002) 209ꢁ
/
214
211
2.4. Synthesis of [CuBr(o,o?-iPr2-p-BrC6H2-BIAN)]2
(3)
Table 1
Crystallographic data for complex 3
Crystal data
After dissolving o,o?-iPr2C6H3-BIAN (0.30 g; 0.6
mmol) in a small amount of chloroform (99%), 18 ml
Empirical formula
Formula weight
Crystal system
Space group
C36H38Br3CuN2
801.95
monoclinic
P21/n
of a chloroformꢁacetic acid solution (3:1) was added.
/
This reaction mixture was heated to 60 8C and mixed
with a methanol solution (5 ml) of CuBr2 (0.07 g; 0.3
mmol). After heating to reflux, another 5 ml of
methanol CuBr2 solution (0.07 g; 0.3 mmol) was added
and the mixture was stirred for 2 h at r.t. The product
was isolated as a brown powder; yield: 69%, and
purified by chromatography on silica gel using dichlor-
omethane as eluent. Crystals suitable for the X-ray
measurement were obtained directly from the mother
liquor by free evaporation in air. C36H38Br3N2Cu
(801.9): Calc. C 53.92, H 4.78, N 3.49%. Found. C
˚
a (A)
13.9939(2)
15.0192(2)
17.1426(2)
90.00
˚
b (A)
˚
c (A)
a, x (8)
b (8)
78.47 (2)
3530.24(8)
4
3
˚
V (A )
Z
Dcalc (g cmꢃ3
F(000)
m (mmꢃ1
Crystal size (mm)
)
1.51
1608
)
4.066
0.5ꢄ0.2ꢄ0.2
Data collection
Temperature (K)
uRange (8)
Radiation
293(2)
53.91, H 5.11, N 3.40%. UVꢁ
568 nm. meff (24 8C): diamagnetic. H NMR (CD2Cl2,
300.40 MHz, 24 8C): dꢀ1.05 (d, H20), 1.28 (d, H21),
/
Vis (lmax, nm; DCE): 480,
1
1.72ꢁ27.45
/
˚
Mo Ka (Mon), 0.71069 A
v
/
Scan mode
Dataset
2.97 (sept, H19), 6.80 (d, H4), 7.50 (pst, H5), 8.10 (d,
H6). 13C NMR spectrum was not recorded due to low
solubility.
ꢃ185h 517; ꢃ195k 518; ꢃ205l 522
23 383
Total data
Unique data
Observed data
8010
5157 [I ꢀ2.00s(I)]
Refinement
2.5. X-ray data collection and structure refinement
Refined parameters 387
Final R, wR
0.0685, 0.1954
Crystallographic data for complex 3 are summarized
in Table 1. Crystal data were collected with a SMART/
RA CCD diffractometer (Mo Ka radiation, graphite
monochromator). The initial structure was solved by
SIR92 [12] and refined by least-squares methods based
on F2 using SHELXL-97 [13]. Thermal ellipsoids (30%
probability) and a molecular plot were drawn using the
ORTEP-III program. The multi-scan empirical absorp-
wꢀ1/[s2(Fo)2ꢂ(0.1152P)2ꢂ7.7947P], where, Pꢀ(Fo2ꢂ2Fc2)/3.
wave numbers in the spectra of complexes thus indicat-
ing the coordination of both diimine nitrogen atoms of
o,o?-iPr2C6H3-BIAN to the metal center in all studied
complexes (Table 2).
Generally, it is known that the aromatic rings with
three adjacent free hydrogen atoms show strong bands
tion correction (Tmin/Tmax
ꢀ0.5575/1.0000) was applied.
/
in the 810ꢁ
750 cmꢃ1 region due to the out-of-plane CH
/
All non-hydrogen atoms were refined anisotropically.
Hydrogen atoms were included in calculated positions
and refined geometrically on their respective carrier
atoms using three common isotropic thermal motion
parameters (mixed treatment).
deformation vibrations [14]. Their position is deter-
mined almost wholly by their location on the ring rather
than by the nature of the substituent and, with certain
limitations, they provide an excellent method for
recognition of the type of substitution. The very high
intensity and sensitivity of these characteristic bands in
this region make them particularly well suited for
quantitative work, too. We noticed that splitting these
out-of-plane CH deformation vibrations bands in the
3. Results and discussion
3.1. Physical properties of Cu(I) and Fe(II) complexes
with the o,o?-iPr2C6H3-BIAN ligand
810ꢁ
750 cmꢃ1 region of complex 1 can be considered as
a sign of the coordination of two Ar-BIAN ligands to
/
The physical data of all metal complexes are listed in
Table 2 in which diamagnetism is observed in case of all
the three studied complexes. Formation of the free o,o?-
iPr2C6H3-BIAN ligand can be confirmed from IR
the copper(I) ion.
In case of iron(II) complex 2, two bands observed at
1575 and 1607 cmꢃ1 were assigned to n(Cꢀ
/
N) vibra-
tions of 2,2?-bipyridyl, which as a free molecule exhibits
Cꢀ
N vibration peaks at 1558 and 1580 cmꢃ1 [15]. A
spectra where only Cꢀ
observed at 1671, 1652, 1642 cmꢃ1 [10], and no Cꢀ
stretching vibrations of the starting diketones in the
1700ꢁ
1800 cmꢃ1 region. Moreover, these bands as-
signed to n(CꢀN) in free ligand are shifted to lower
/N stretching vibrations are
/
/O
shift of these bands to higher wave numbers in IR
spectra of complex 2 indicates the coordination of both
nitrogen atoms of 2,2?-bipyridyl to the iron(II) center.
/
/

212
A. Paulovicova et al. / Inorganica Chimica Acta 339 (2002) 209ꢁ214
/
Table 2
Infrared (cmꢃ1) and electrochemical data of complexes at room temperature
ꢃ
a
b
c
Complex
n(CꢀN)
n(ClO4
)
E1/2
DEp
meff
[Cu(o,o?-iPr2C6H3-BIAN)2](ClO4)(AcOH)2 (1)
[Fe(bipy)2(o,o?-iPr2C6H3-BIAN)](ClO4)2 (2)
[CuBr(o,o?-iPr2-p-BrC6H2-BIAN)] (3)
1669, 1633
1669, 1649
1654, 1635
1116, 621
1090, 622
ꢃ0.31(DCE) ꢃ0.34(ACO)
0.73 (ACO), 0.76 (ACN)
173, 131
73, 84
Diam.
Diam.
Diam.
a
Half-wave potentials E1/2 versus ferrocene/ferrocenium determined by cyclic voltammetry in DCE, ACN, or ACO at 100 mV sꢃ1 scan rate
(electrolyte: 0.1 M Bu4NClO4).
b
Epꢀ(EpaꢃEpc), Epa and Epc are the peak anodic and peak cathodic potentials, respectively.
Magnetic susceptibility, diam.ꢀdiamagnetic.
c
The strong band at around 1100 cmꢃ1 and a sharp band
at 622 cmꢃ1 suggest uncoordinated perchlorate anions
[16] in complexes 1 and 2.
mentioned above, the voltammetric response of complex
1 between 1.3 and ꢃ0.8 V versus ferrocene/ferrocenium
/
indicates the occurrence of chemical reactions coupled
to the various electron transfers. Recently, a complex
sequence of fragmentation steps has been proposed for
related diimine systems under similar conditions [21]. A
detailed investigation of such processes, however, was
not attempted in the present study.
Low-spin iron(II) octahedral complexes are formed
with ligands, which have a strong ligand field. The Ar-
BIAN ligand satisfies such a requirement as we have
succeeded to synthesize the diamagnetic [Fe(bipy)2(o,o?-
iPr2C6H3-BIAN)](ClO4)2 complex (2). The absorption
spectrum of complex 2 shows three bands: 418 (the
intra-ligand (IL) diimine transition), 479 and 600 nm
(the MLCT transitions). However, this assignment must
be regarded as tentative since low-spin iron(II) com-
plexes present, are considerable assignment difficulties
due to the strong intensities of bands in rather narrow
range of wavelengths [22].
the Fe (II/III) couple was assessed by using cyclic
voltammetry in various solvents. Based on peak-to-peak
separation (DEp), where, reversible behavior is com-
monly reported between 60 and 80 mV in organic
solvents [22], complex 2 exhibited reversible redox
behavior that appeared to progress from reversible in
acetone (ACO) to quasi-reversible in acetonitrile
(ACN), see Table 2. No ligand reduction has been
observed.
Electronic spectral data of complex 1 in various
solvents and in the solid state are shown in Table 3.
This complex absorbs in a broad region of the UV and
visible spectra, showing very intense ligand-centered
(LC) bands in the UV region and weaker metal-ligand
charge-transfer bands (MLCT) in the visible region
similar to those observed with other Cu(I) diimine
systems [17]. Moreover, in the spectra of complex 1 in
various organic solvents, there is a low-energy shoulder
appearing in the 564ꢁ580 nm range. This shoulder has
/
been attributed to result from a flattened distortion of
the complex from D2d symmetry as it was observed in
the case of bis(phenanthroline)copper(I) complexes [18ꢁ
/
20]. This low-symmetry conformation likely occurs to
maximize intra-molecular p-stacking interactions be-
tween opposing ligands. Thus, the intensity of the low-
energy shoulder can be considered as a rough measure
of the distortion away from D2d symmetry. On the basis
of these considerations, it can be concluded that a
significant ‘flattening’ distortion occurs about the cop-
per ion in the MLCT state of [Cu(o,o?-iPr2C6H3-
BIAN)2]ꢂ.
The redox behavior of complex 1 was studied by
cyclic voltammetry. It undergoes a quasi-reversible one-
electron oxidation process in 1,2-dichloroethane (DCE)
and acetone (ACO) (Table 2), which can be attributed to
the Cu(I)l
/
Cu(II) couple:
3.2. The synthesis and the structure of [CuBr(o,o?-iPr2-
p-BrC6H2-BIAN)]2 (3)
[Cu(o; o?iPr2C6H3BIAN)2]2ꢂ ꢂeꢃ
l [Cu(o; o?iPr2C6H3BIAN)2]ꢂ
During our attempt to synthesize the bromide analo-
gue to the [Cu(AcOH)Cl2(o,o?-iPr2C6H3-BIAN)] com-
Moreover, except the Cu(I)/Cu(II) redox process
Table 3
a
UVꢁVis spectroscopic data (lmax per nm) of complex 1 at room temperature
/
Solid
DCE
576 (sh)
564 (sh)
569 (sh)
580 (sh)
569 (sh)
480
458
360
494 (6000)
458 (5500)
455 (1100)
460 (4200)
459 (8000)
432 (6300)
425 (1300)
435 (4700)
435(7000)
405(5600)
368(8500)
376(5000)
367(1500)
367(6500)
Chloroform
Toluene
THF
a
The extenction coefficient values are shown in parenthesis, shꢀshoulder.

A. Paulovicova et al. / Inorganica Chimica Acta 339 (2002) 209ꢁ
/
214
213
plex, an additional factor suddenly came into play.
Bromination of the phenyl rings of o,o?-iPr2C6H3-BIAN
took place in the para position, as a result of the
reduction of Cu(II) to Cu(I), which evidenced by the X-
ray analysis. This method can be considered as a new
possible route of p-bromination of the phenyl group
using Cu(II) bromide in organic chemistry.
An ORTEP plot showing the atomic numbering scheme
is given in Fig. 1. Selected bond distances and angles are
listed in Table 4. The copper(I) ion is tetrahedrally
surrounded by the two nitrogen atoms N(1) and N(2) of
o,o?-iPr2-p-BrC6H2-BIAN, and by the two bromide
atoms Br(1) and Br(1?). The copper atoms lie out of
the Ar-BIAN ligand plane [C(13)N(1)C(1)C(2)N(2)-
Table 4
˚
Selected bond lengths (A), angles (8), and torsion angles (8) for
complex 3
Cu(1)ꢁN(1)
Cu(1)ꢁN(2)
Cu(1)ꢁBr(1)
Cu(1)ꢁBr(1‘)
N(1)ꢁC(1)
N(1)ꢁC(13)
N(2)ꢁC(2)
N(2)ꢁC(25)
C(1)ꢁC(2)
2.110(4)
2.112(4)
2.3662(11)
2.4791(11)
1.287(6)
1.452(6)
1.283(6)
1.441(6)
1.517(6)
1.476(7)
1.462(7)
C(2)ꢁC(3)
C(1)ꢁC(11)
N(1)ꢁCu(1)ꢁN(2)
N(1)ꢁCu(1)ꢁBr(1)
N(2)ꢁCu(1)ꢁBr(1)
Br(1)ꢁCu(1)ꢁBr(1‘)
Cu(1)ꢁN(1)ꢁC(1)
Cu(1)ꢁN(1)ꢁC(13)
Cu(1)ꢁN(2)ꢁC(2)
Cu(1)ꢁN(2)ꢁC(25)
C(1)ꢁN(1)ꢁC(13)
C(2)ꢁN(2)ꢁC(25)
80.17(15)
118.66(12)
119.67(12)
114.98(3)
110.9(3)
˚
C(25)] by 0.79 A.
Appraisal of the obtained structural data of complex
3 reveals some interesting features. Firstly, comparison
of the bond lengths and angles in 3 with those of free
bis(p-tolylimino)acenaphthene (p-Tol-BIAN) [10] shows
some discrepancies that must result from the coordina-
tion to the copper atom and from the different aromatic
groups on the imine N-atoms. These differences concern
129.5(3)
110.4(3)
129.4(3)
119.4(4)
120.1(4)
C(30)ꢁC(25)ꢁN(2)ꢁC(2)
C(18)ꢁC(13)ꢁN(1)ꢁC(1)
C(26)ꢁC(25)ꢁN(2)ꢁC(2)
C(14)ꢁC(13)ꢁN(1)ꢁC(1)
C(2)ꢁC(3)ꢁC(12)ꢁC(11)
C(3)ꢁC(12)ꢁC(11)ꢁC(1)
N(2)ꢁC(2)ꢁC(1)ꢁN(1)
C(3)ꢁC(2)ꢁC(1)ꢁC(11)
ꢃ78.6(6)
84.7(6)
the imine Cꢀ
/
N bonds, N(1)ꢁ
/
C(1) and N(2)ꢁ
/
C(2) of
1.287(6) and 1.283(6) A, respectively, which are longer
˚
105.8(6)
ꢃ99.8(6)
ꢃ0.2(6)
ꢃ0.2(6)
ꢃ0.2(7)
ꢃ0.7(5)
˚
than those of the free (p-Tol-BIAN) ligand (1.267(3) A).
Due to its coordination to a metal, the bis(imino)ace-
naphthene moiety almost reaches planarity, as it is
apparent from the torsion angles [N(2)ꢁ
N(1)ꢀ 0.2(7)8 and C(3)ꢁC(2)ꢁC(1)ꢁ
0.7(5)8]. In p-Tol-BIAN, the corresponding values are
6.5(3) and ꢃ5.6(2)8. Secondly, compared with other
/
C(2)ꢁ
/
C(1)ꢁ
/
/
ꢃ
/
/
/
/
C(11)ꢀ
/
ꢃ
/
ClO4, respectively]. The bite angle Nꢁ
in the following order: 81.81(5)8 in [Cu(acac)-
(AcOH)(o,o?-iPr2C6H3-BIAN)]ClO4,
[Cu(AcOH)Cl2(o,o?-iPr2C6H3-BIAN)],
[CuBr(dmphen)]2 and 80.17(15)8 in 3. This decrease in
the NꢁCuꢁN angle is accompanied by bending of the
aromatic groups on the imine N atoms more towards
the copper center and away from the naphthalene
backbone. The rigid naphthalene moiety and the aro-
matic groups with o- and p-substituents show no
anomalies and the bond distances and angles are within
the expected ranges [14].
/
Cuꢁ/N decreases
ꢃ
/
/
two copper(II) complexes with o,o?-iPr2C6H3-BIAN
coordinated in a bidentate fashion and one copper(I)dii-
mine complex, namely [Cu(acac)(AcOH)(o,o?-iPr2C6H3-
80.36(8)8
80.32
in
in
BIAN)]ClO4,
and [CuBr(dmphen)]2 (dmphenꢀ
phenanthroline) [23], respectively. An increase in the
CuꢁN distance is apparent [the average CuꢁN distances
are 2.1114, 2.08445, 2.0702 and 2.0454 A in 3,
[CuBr(dmphen)]2, [Cu(AcOH)Cl2(o,o?-iPr2C6H3-
[Cu(AcOH)Cl2(o,o?-iPr2C6H3-BIAN)]
/
/
/2,9-dimethyl-1,10-
/
/
˚
BIAN)] and [Cu(acac)(AcOH)(o,o?-iPr2C6H3-BIAN)]-
4. Supplementary material
The crystallographic data of 3 reported in this paper
have been deposited with the Cambridge Crystallo-
graphic Data Center with the supplementary publication
number 162037. Copies of the data may be obtained free
of charge from The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (fax: +441223-336-033; e-
mail: deposti@ccdc.cam.ac.uk or www:http.//www.ca-
m.ac.uk).
Fig. 1. An ORTEP plot (30% probability level) of [CuBr(o,o?-iPr2-p-
BrC6H2-BIAN)]2 (3).

214
A. Paulovicova et al. / Inorganica Chimica Acta 339 (2002) 209ꢁ214
/
[10] A. Paulovicova, U. El-Ayaan, K. Shibayama, T. Morita, Y.
Acknowledgements
Fukuda, Eur. J. Inorg. Chem. (2001) 2641.
[11] E. Konig, Magnetic Properties of Coordination and Organo-
¨
The authors thank Dr. Z. Fazekas of Institute of
Research and Innovation in Chiba (Japan) for his help
with the NMR. This work was partly supported by a
Grant-in-Aid for Scientific Research (No. 11304046)
from the Ministry of Education, Science, Culture and
Sports of Japan.
metallic Transition Metal Compounds, Springer-Verlag, Berlin,
1966.
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Burla, G. Polidori, M. Camalli, J. Appl. Crystallogr. 27 (1994)
435.
[13] G.M. Sheldrick, Program for the Refinement of Crystal Struc-
tures, University of Gottingen, Gottingen, Germany, 1997.
¨ ¨
[14] M. Burke-Laing, M. Laing, Acta Crystallogr., B 32 (1976) 3216.
[15] L.J. Bellamy, The Infrared Spectra of Complex Molecules, Wiley,
New York, 1954.
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