Synthesis, characterization, and X-ray crystal structures of bis [N-(3,3-diphenylallylidene)quinolin-8-amine-κV,κN 8]copper(1+) tetraphenylborate(1-)

Article abstract of DOI:10.1002/hlca.200690031

Two new ligands, N-(3,3-diphenylallylidene)quinolin-8-amine (dpa-qa; L ¹) and N,N′-bis-(3,3-diphenylallylidene)[1,1′-biphenyl]- 2,2′-diamine (bdpa-bda; L²), and their corresponding copper(I) complexes, [Cu(dpa-qa)₂]BPh

Full text of DOI:10.1002/hlca.200690031

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Synthesis, Characterization, and X-Ray Crystal Structures of Bis[N-(3,3-
diphenylallylidene)quinolin-8-amine-kN,kN8]copper(1+)
Tetraphenylborate(1ꢀ) ([Cu(dpa-qa)2]BPh4) and Bis[N,N’-bis(3,3-
diphenylallylidene)-[1,1’-biphenyl]-2,2’-diamine-kN,kN’]copper(1+)
Perchlorate ([Cu(bdpa-bda)2]ClO4 ·3 H2O)
by Mehdi Amirnasr*a), Guido Kickelbickb), and Saeed Dehghanpourc)
a) Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran
(fax: +98-311-3912350; e-mail: amirnasr@cc.iut.ac.ir)
b) Vienna University of Technology, Institute of Materials Chemistry, Getreidemarkt 9/165,
A-1060 Vienna
c) Department of Chemistry, Alzahra University P. O. Box 1993891176 Tehran, Iran
Two new ligands, N-(3,3-diphenylallylidene)quinolin-8-amine (dpa-qa; L1) and N,N’-bis-(3,3-diphe-
nylallylidene)[1,1’-biphenyl]-2,2’-diamine (bdpa-bda; L2), and their corresponding copper(I) complexes,
[Cu(dpa-qa)2]BPh4 (1) and [Cu(bdpa-bda)2]ClO4 ·3 H2O (2), were synthesized and characterized by
C,H,N analyses, 1H- and 13C-NMR, IR, and UV/VIS spectroscopy. The crystal and molecular structures
of 1 and 2 were determined by X-ray crystallography from single-crystal data. Complex 1 crystallizes in
the orthorhombic space group Pbca, with a=14.391(3) Å, b=21.967(5) Å, c=35.463(8) Å, V=11211(4)
Å3, and Z=8. Complex 2 crystallizes in the monoclinic space group C2/c, with a=30.746(10) Å,
b=18.244(6) Å, c=27.835(9) Å, b=109.794(7)8, V=14691(8), and Z=8. The coordination polyhedron
about the CuI center in the two complexes is best described as a distorted tetrahedron. A quasireversible
redox behavior is observed for complex 1 and 2 (E1/2 =0.58 and 1.04 V).
1. Introduction. – There has been a growing interest in the synthesis and character-
ization of copper(I) complexes of p-acceptor ligands such as diimines, due to their
potential application as photosensitizers [1–6]. Most of the studies have been on
four-coordinated tetrahedral CuI complexes of the type [Cu(LL)2]+ or [Cu(LL)(P)2]+
where LL is a substituted phenanthroline and P is a phosphine [7–14]. Some of
these complexes possess broad absorption bands in the VIS region with high extinction
coefficients potentially useful for solar-energy harvesting [15–18]. The d10 configura-
tion of CuI and p* molecular orbitals of the ligands combine to produce metal-to-ligand
charge-transfer (MLCT) states. The MLCT transitions can be tuned to lower energies
by introducing a ligand with a low-lying p* molecular orbital. The steric, electronic, and
conformational interactions influence the redox potential of these complexes and mod-
ify their excited-states properties [15]. A thorough understanding of these effects will
serve as the basis for a rational design of complexes with specific and predictable prop-
erties [3][19].
Our interest in the chemistry of copper(I) complexes with new synthetic ligands was
stimulated by the question how the variations in the backbone of the ligands will influ-
ence their reactivity and the physicochemical and spectral properties of their copper(I)
© 2006 Verlag Helvetica Chimica Acta AG, Zürich

Helvetica Chimica Acta – Vol. 89 (2006)
275
Fig. 1. Ligands L1 and L2, and CuI complexes 1 and 2
complexes as compared to those containing polypyridine ligands. Factors such as the
delocalization of electron density provide a span of charged species from a single neu-
tral precursor and low-energy MLCT pathways, which are important in electro- and
photocatalysis.
In continuation of our work on the preparation of (diimine) copper(I) complexes
with low-lying MLCT transitions [19], we now report the synthesis and characterization
of two new ligands L1 and L2 with extended conjugation and their copper(I) complexes
1 and 2 (Fig. 1). The structures, spectral properties, and redox chemistry of these com-
plexes are also discussed.
2. Results and Discussion. – 2.1. Spectral Data. The IR spectra of the free ligands
exhibit the characteristic band of the imine group, which appears at 1583 and 1598
cmꢀ1 for L1 and L2 respectively. This band is shifted to lower frequencies in the IR spec-
tra of the corresponding complexes due to the coordination of the imine N-atom [20],
and appears at 1576 cmꢀ1 in 1 and 1590 cmꢀ1 in 2. A strong band at ca. 1085 cmꢀ1 in the
IR spectrum of 2 is characteristic of the asymmetric ClꢀO stretching mode of the per-
chlorate anion [21].
The electronic absorption spectra of the ligands L1 and L2 and the corresponding
complexes 1 and 2 are presented in Table 1. Since no d-d transitions are expected for
a d10 complex, the UV/VIS bands are assigned to MLCT or ligand-centered p ! p*
transitions [22]. The absorption spectrum of [Cu(dpa-qa)2]BPh4, (1) in CHCl3 features
a band with a true maximum at 503 nm (Fig. 2), whereas [Cu(bdpa-bda)2]ClO4 (2)
shows a clear shoulder at 428 nm. This observation is in agreement with a higher con-
jugation in the coordinated dpa-qa (L1) relative to bdpa-bda (L2), which conforms to
the X-ray data (vide infra). In addition, the lower energy of the MLCT band is in accord

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with the observed lower redox potential of complex 1 relative to that of complex 2.
Interestingly, the position (lmax 503 nm) and the intensity (e 6357) of the MLCTabsorp-
tion band of complex 1 are comparable to those reported for the most attractive com-
plex of this series, [Cu(dmesp)(dpep)](PF6) (lmax 500 nm, e 5300; dmesp=2,9-dimesi-
tyl-1,10-phenanthroline, dpep=2,9-diphenylethynyl-1,10-phenanthroline), [23]. The
considerable red shift in the position of the first MLCT band of complex 1 as compared
to that of other bis(diimine)copper(I) complexes is quite interesting and points to the
possible application of this complex as a more efficient charge-transfer photosensitizer
in the VIS region. Additional absorption bands are also observed in the spectra of 1 and
2 in CHCl3 in the UV region (Table 1). The intensity of these bands are consistent with
their assignment to ligand-centered p ! p* or/and charge-transfer transitions.
Table 1. UV/VIS Data (CHCl3) of Ligands L1 and L2 and of Complexes 1 and 2
lmax/nm (log e/Mꢀ1cmꢀ1
)
L1, dpa-qa
358 (17113),
350 (25027),
503 (6357),
428 (1445),
314 (23217)
308 (45807)
373 (53367)
372 (25819),
L2, bdpa-bda
1, [Cu(dpa-qa)2]BPh4
2, [Cu(bdpa-bda)2]ClO4
329 (63880)
Fig. 2. Electronic absorption spectrum (CHCl3, 298 K) of [Cu(dpa-qa)2]BPh4 (1)
The 1H-NMR spectrum of complex 1 shows that several of the aromatic protons are
nonequivalent due to the presence of the asymmetric ligand dpa-qa (L1) (Fig. 3). A
total of 13 nonequivalent aromatic protons are observed due to the ligand and the

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Fig. 3. 1H-NMR Spectrum (CDCl3, 298 K) of [Cu(dpa-qa)2]BPh4 (1)
Ph4Bꢀ ion. Since the electronic environment around most of the aromatic protons is
similar, their signals appear in a narrow range of chemical shifts which is crowded
due to the overlap of several signals. However, the presence of the expected number
of aromatic protons of the complex is evident from the direct comparison of the inten-
sity of the aromatic-proton signals with those of the clearly observable imine proton
CH=N (=Hd) and aromatic protons Ha and Hc. The signal of CH=N (d 8.53) in the
complex is deshielded relative to the free ligand (d 8.28) due to the deshielding effect
resulting from the coordination of the ligand.
The 1H-NMR spectrum of complex 2 shows a d at d 7.89 due to the CH=N protons.
The C=CHCH=N protons overlap with the aromatic protons of the phenyl rings, and
they all appear in the d 6.46–7.38 region.
The sharp NMR peaks are indicative of diamagnetic CuI complexes. In principle,
geometrical isomers are possible with respect to the C=N bond as shown in Fig. 4.
However, the appearance of a unique signal for each type of proton in CDCl3 solution
indicates that the symmetry of the molecules is retained in solution, and only one iso-
mer is present.
Fig. 4. Possible geometrical isomers of the ligands

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2.2. X-Ray Structures of [Cu(dpa-qa)2]BPh4 (1) and [Cu(bdpa-bda)2]ClO4 ·3 H2O
(2). The crystallographic data are summarized in Table 2, and selected bond distances
and angles are given in Table 3. A view of the cation of complex 1, including the atom-
numbering scheme is illustrated in Fig. 5. While a tetrahedral geometry might be
expected for a four-coordinated copper(I) center, the coordination sphere around
the metal ion in this complex is distorted by the restricting bite angles of the chelating
ligand. The intraligand N(1)ꢀCu(1)ꢀN(11) and N(27)ꢀCu(1)ꢀN(37) angles are much
less than 109.58, being only 80.94(9)8 and 81.19(9)8, respectively. On the contrary, the
N(1)ꢀCu(1)ꢀN(27) and N(1)ꢀCu(1)ꢀN(37) angles (137.13(9)8 and 130.50(9)8, resp.)
are much larger than those of a tetrahedral complex. The average CuꢀN bond distance
(2.052 Å) is similar to that found in the [Cu(dpdmp)2]+ cation (2.047 Å; dpdmp=2,9-
diphenyl-4,7-dimethyl-1,10-phenanthroline) at room temperature [20] and in other
CuI pseudotetrahedral complexes (typical CuꢀNav =2.055 Å) [19][23].
Table 2. Crystal Data and Structure Refinement for 1 and 2
1
2
Empirical Formula
C72H56BCuN4
C84H70ClCuN4O7
Mr
1051.56
1346.48
T/K
294(2)
297(2)
Wavelength/Å
0.71073
0.71073
Crystal system
orthorhombic
monoclinic
Space group
Pbca
C2/c
a/Å
14.391(3)
30.746(10)
b/Å
21.967(5)
18.244(6)
c/Å
35.463(8)
27.835(9)
a/8
90
90
b/8
90
109.794(7)
g/8
90
11211(4)
8, 1.246
0.437
90
14691(8)
8, 1.212
0.390
V/Å3
Z, Dcalc./Mg·mꢀ3
m/mmꢀ1
F(000)
4400
5584
Crystal size/mm
q/8
h/k/l
0.46×0.32×0.28
1.79 to 23.26
ꢀ13, 15/ꢀ22, 24/ꢀ39, 39
49114
0.40×0.30×0.10
1.41 to 23.25
ꢀ21, 34/ꢀ19, 20/ꢀ30, 30
Refl. collected
34096
Independent refl.
R(int)
8037
0.0500
10516
0.0530
Completeness to q (23.268)/%
Observed intensities>2s
Max. and min. transmission
Data, restraints, parameters
Goodness-of-fit on F2
Final R indices (I>2s(I))a)
R indices for all dataa)
Extinction coefficient
Largest difference peak and hole/e·Åꢀ3
99.9
5863
99.7
6335
0.8873 and 0.8242
8037, 0, 704
1.028
R1 =0.0394, wR2 =0.0908
R1 =0.0645, wR2 =0.1037
0.00042(7)
0.9620 and 0.8595
10516, 0, 874
1.003
R1 =0.0557, wR2 =0.1425
R1 =0.1077, wR2 =0.1706
–
0.210 and ꢀ0.289
2
0.554 and ꢀ0.550
1
2
2
2
2 2
[*] R1 =S jjFojꢀjFcjj/SjFoj, wR2 ={S[w(Fo ꢀFc ) ]/S[w(Fo) ]} .

Helvetica Chimica Acta – Vol. 89 (2006)
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Table 3. Selected Bond Lengths [Å] and Bond Angles [8] for 1 and 2
1
2
Cu(1)ꢀN(1)
Cu(1)ꢀN(11)
Cu(1)ꢀN(27)
Cu(1)ꢀN(37)
N(11)ꢀC(12)
N(11)ꢀC(9)
N(1)ꢀC(10)
N(1)ꢀC(2)
1.992(2)
2.117(2)
1.994(2)
2.105(2)
1.291(3)
1.412(3)
1.370(3)
1.325(3)
1.433(3)
1.345(3)
1.381(4)
1.479(3)
Cu(1)ꢀN(1)
Cu(1)ꢀN(14)
Cu(1)ꢀN(58)
Cu(1)ꢀN(45)
N(1)ꢀC(15)
N(1)ꢀC(2)
2.034(3)
2.033(3)
2.045(3)
2.009(3)
1.282(5)
1.427(5)
1.437(5)
1.281(5)
1.437(5)
1.342(5)
1.502(5)
1.382(6)
N(14)ꢀC(13)
N(14)ꢀC(30)
C(59)ꢀC(60)
C(60)ꢀC(61)
C(7)ꢀC(8)
C(12)ꢀC(13)
C(13)ꢀC(14)
C(14)ꢀC(15)
C(14)ꢀC(21)
C(6)ꢀC(5)
N(1)ꢀCu(1)ꢀN(11)
N(1)ꢀCu(1)ꢀN(27)
N(1)ꢀCu(1)ꢀN(37)
N(11)ꢀCu(1)ꢀN(37)
N(27)ꢀCu(1)ꢀN(37)
Cu(1)ꢀN(1)ꢀC(2)
Cu(1)ꢀN(1)ꢀC(10)
Cu(1)ꢀN(11)ꢀC(9)
Cu(1)ꢀN(11)ꢀC(12)
C(2)ꢀN(1)ꢀC(10)
C(9)ꢀN(11)ꢀC(12)
80.94(9)
137.13(9)
130.50(9)
101.78(8)
81.19(9)
N(1)ꢀCu(1)ꢀN(14)
N(1)ꢀCu(1)ꢀN(45)
N(1)ꢀCu(1)ꢀN(58)
N(45)ꢀCu(1)ꢀN(58)
N(45)ꢀCu(1)ꢀN(14)
Cu(1)ꢀN(1)ꢀC(2)
Cu(1)ꢀN(1)ꢀC(15)
Cu(1)ꢀN(14)ꢀC(13)
Cu(1)ꢀN(14)ꢀC (30)
C(13)ꢀN(14)ꢀC(30)
C(2)ꢀN(1)ꢀC(15)
105.32(13)
102.56(13)
121.67(13)
106.51(13)
124.28(13)
113.1(2)
125.5(3)
108.9(2)
129.4(3)
117.6(3)
126.9(2)
114.82(17)
110.91(16)
122.38(17)
118.3(2)
121.7(2)
118.8(3)
The ligand adopts a trans configuration in complex 1. The mean value for the dihe-
dral angles of N=CꢀC=C is 9.568 (N(11)ꢀC(12)ꢀC(13)ꢀC(14)) and 3.628 (N(37)ꢀ
C(38)ꢀC(39)ꢀC(40)) indicating that this moiety is roughly planar. This degree of
coplanarity, which allows for increased p-conjugation in the ligand, is consistent with
the observed CꢀC bond distances in the coordinated ligand: C(14)ꢀC(13)
1.345(3)Å<C(13)ꢀC(12) 1.433(3)Å<typical single CꢀC bond, 1.507(5)Å [19].
Due to the geometrical restrictions in 1, the C=CHCH=N protons, i.e., the H-atoms
at C(13) and C(39), lie in the vicinity of the metal atoms making the intramolecular
interactions possible in the form of weak CꢀH···M H-bonds. This type of interaction
is somewhat similar to the agostic interactions found in many organometallic com-
plexes [24][25], though a CꢀHd+···Mdꢀ charge-assisted H-bonding could be encoun-
tered here. As a matter of fact, the involvement of the metal centers in H-bonding is
now well established and known as nontraditional H-bonds [26][27]. A recent survey
by Desiraju and Steiner [28] gives the range 2.5–3.2 Å for the weak (Cꢀ)H···M H-
bonds. Our structural data reveal that the (Cꢀ)H···M interactions ranging from 2.855
to 3.091 Å would meet the criteria and can be regarded as intramolecular weak H-
bonds. Such an interaction may be responsible for the large values of the N(1)ꢀ
Cu(1)ꢀN(27) (137.13(9)8) and N(1)ꢀCu(1)ꢀN(37) (130.50(9)8) angles relative to the
smaller value for N(11)ꢀCu(1)ꢀN(37) (101.78(8)8). The possibility of this type of inter-
action has also been reported by others for closely related structures [29][30].

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Fig. 5. View of the structure of [Cu(dpa-qa)2]+ showing the atom labeling scheme
The cation of complex 2, along with the atom-numbering scheme, is shown in Fig. 6.
As in complex 1, the geometry about CuI in 2 is also distorted by the restricting bite
angles of the bulky chelating ligand. The N(1)ꢀCu(1)ꢀN(14) and N(45)ꢀCu(1)ꢀ
N(58) angles are 105.32(13)8 and 106.51(13)8, respectively. However, the N(1)ꢀ
Cu(1)ꢀN(58) and N(45)ꢀCu(1)ꢀN(14) angles are 121.67(13)8 and 124.28(13)8, respec-
tively, and the dihedral angle between the two chelate rings is 73.388. The dihedral
angles between the two Ph rings of biphenyl is 68.948 (C(2)ꢀC(13)) and 71.578
(C(46)ꢀC(57)), resulting in a bite size of 3.233 Å for d(N(1)ꢀN(14)) and 3.248
d(N(45)ꢀN(58)) for the two chelating ligands. The average CuꢀN bond distance
(2.030 Å) is similar to that found in other [CuI(diimine)] pseudotetrahedral complexes
[20][23].
In spite of sterical hindrance in these complexes, each coordinated ligand adopts a
trans configuration. The mean value for dihedral angles N=CꢀC=C is ca. 5.168 indicat-
ing the planarity of this moiety. However, the two N=CꢀC=C moieties in 2 are not
coplanar.
The average dihedral angle between the two Ph rings of biphenyl in 2 is 70.268 and,
in principle, the ligand bdpa-bda (L2) can form a chiral bis(diimine)copper(I) complex.

Helvetica Chimica Acta – Vol. 89 (2006)
281
Fig. 6. View of the structure of [Cu(bdpa-bda)2]+ showing the atom labeling scheme
1
However, 13C-NMR data, sharp H-NMR signals in solution, and the X-ray analysis
show that high diastereoselective complexation occurs in solution and in the solid
state probably due to the steric hindrance in the complex [31][32].
The structural and electronic properties of complexes 1 and 2, and a comparison
between the two are interesting. In 1, the angle between the planes C(9)ꢀC(8)ꢀ
N(11) and C(13)ꢀC(12)ꢀN(11) is 28.868, and that between the planes C(39)ꢀ
C(38)ꢀN(37) and C(34)ꢀC(35)ꢀN(37) is 3.778. However, the average dihedral angle
between the two Ph rings of biphenyl in 2 is 70.268, and the angle between the planes
C(3)ꢀC(2)ꢀN(1) and C(16)ꢀC(15)ꢀN(1) is 52.468 and that between the planes
C(75)ꢀC(74)ꢀN(58) and C(56)ꢀC(57)ꢀN(58) is 53.378. A comparison between the
angles in 1 and 2 indicates that there is a higher degree of conjugation in 1 relative
to 2 leading to a considerable red shift (75 nm) in its MLCT position. Both structures
do not show any ordering in their packing related to p-p interactions or H-bonds.
2.3. Electrochemistry. The electrochemistry of compounds 1 and 2 were investigated
in CH2Cl2. The two ligands L1 and L2 are electroinactive in the working potential
region. The complexes show a quasireversible CuII/I couple with E1/2 of 0.58 and 1.04
V, respectively. The ratio of the anodic and cathodic peak currents, ipa/ipc, approaches
1 as the scan rate increases. The peak-to-peak separation varies from 120 to 180 mV
for 1 and 120 to 180 mV for 2 as the scan rate is changed from 50 to 500 mV/s.
The CuII/I potential in a CuIN4 chromophore is believed to increase with increasing
p-acidity of the ligands and the resistance to tetrahedral distortion occurring in the cor-
responding CuIIN4 chromophore [23][33][34]. Although a higher degree of conjugation
exists in dpa-qa relative to bdpa-bda (vide supra), the existence of bulkier ligands in 2
which prevent the inner-sphere reorganization to a flattened tetrahedral, more appro-

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priate to CuII oxidation state, play a key role in shifting the oxidation potential to higher
values for complex 2 relative to 1.
1
3. Conclusions. – The CuI complexes show pseudotetrahedral symmetry, and H-
NMR data support the existence of CuI in 1 and 2. The position of MLCT changes con-
siderably and is red shifted by 75 nm, when the bdpa-bda ligand is replaced by dpa-qa.
A major finding of the present work is that the chelating diimine ligand is in the trans
configuration as indicated in structures 1 and 2. Additional steric hindrance in complex
2 relative to 1 results in a more positive CuII/I redox potential.
M. A. and S. D. would like to acknowledge the Isfahan University of Technology and Alzahra Uni-
versity Research Council for partial support of this work. We also thank Mr. Bijanzadeh for obtaining the
NMR spectra. G. K. thanks the Fond zur Förderung der wissenschaftlichen Forschung, Austria, for the
support of this work.
Experimental Part
1. General. Caution! Perchlorate salts of metal complexes with organic ligands are potentially explo-
sive and should be handled with care. All chemicals used were reagent grade and used as received. Sol-
vents used for the reactions were purified by known methods [35]. [Cu(MeCN)4]ClO4 and
[Cu(MeCN)4]BPh4 were freshly prepared according to [36][37]. Voltamograms: Metrohm multipurpose
instrument, model 693 VA, processor with 694A Va stand; three-electrode system consisting of an Ag/
AgCl reference electrode, a Pt-wire counter electrode, and the Au as a working electrode; the test
soln. was purged with Ar for at least 5 min. UV/VIS Spectra: Jasco-V-570 spectrophotometer; lmax
(log e) in nm. IR Spectra: Shimadzu-IR-460 instrument; in cmꢀ1. NMR Spectra: Bruker-Avance-
DRX500 (500 MHz) spectrometer, d in ppm rel. to SiM4 as internal standard. Elemental analyses
were performed with a Heraeus CHN-O-Rapid elemental analyzer.
2. Syntheses. N-(3,3-Diphenylallylidene)quinolin-8-amine (dpa-qa; L1). To a soln. of 3,3-diphenyl-
prop-2-enal (208 mg, 1 mmol) in EtOH (20 ml) was added a soln. of quinolin-8-amine (144 mg, 1
mmol) in EtOH (10 ml) and stirred for 2 h. The formed yellow microcrystalline precipitate was filtered
off, washed with cold EtOH, and dried in air: 300 mg (90%) of L1. IR (KBr): 1583 (C=N). 1H-NMR (500
2
3
MHz, CDCl3): 7.08–7.59 (m, He, 15 arom. H); 8.11 (dd, 1 H, J=8.2, J=1.4, Hc); 8.28 (d, 1 H, J=9.4,
Hd); 8.99 (dd, 1 H, 2J=4, 3J=1.4, Ha). 13C-NMR (125 MHz, CDCl3): 117.63; 121.47; 125.16; 126.72;
127.86; 128.19; 128.26; 128.38; 128.46; 128.90; 129.12; 130.58; 135.92; 138.35; 140.81; 142.72; 150.09;
150.33; 154.25; 162.35 (C=N). Anal. calc. for C24H18N2: C 86.20, H 5.43, N 8.38; found: C 86.25, H
5.44, N 8.39.
N,N’-Bis(3,3-diphenylallylidene)-[1,1’-biphenyl]-2,2’-diamine (bdpa-bda; L2). To a soln. of 2,2’-dini-
tro-1,1’-biphenyl (4 g, 16 mmol) in EtOH (50 ml) was added 5% Pd/C (1 g), and the mixture was warmed
up to 508. A soln. of 80% hydrazine hydrate (15 ml) in EtOH (20 ml) was then added dropwise with vig-
orous stirring within 1 h. The mixture was refluxed for 2 h and then filtered. The filtrate was concentrated
to ca. 5 ml. After the addition of H2O (20 ml) and stirring for 5 min, the resulting white microcrystalline
precipitate was filtered off, washed with H2O and dried in air: 2.56 g (85%) of [1,1’-biphenyl]-2,2’-dia-
1
mine. IR (KBr): 3350 (NH). H-NMR (500 MHz, CDCl3): 3.68 (s, 2 NH2); 6.75–7.18 (m, 8 arom. H).
To a soln. of 3,3-diphenylprop-2-enal (208 mg, 1 mmol) in EtOH (20 ml) was added a soln. of [1,1’-
biphenyl]-2,2’-diamine (92 mg, 0.5 mmol) in EtOH (5 ml) and stirred for 2 h. The obtained yellow micro-
crystalline precipitate was filtered off, washed with cold EtOH, and dried in air: 268 mg (94.4%) of L. IR
1
(KBr): 1598 (C=N). H-NMR (500 MHz, CDCl3): 6.84 (d, J=8.6, 2 arom. H); 6.86 (d, J=9.46, 2 Hg);
6.96–7.33 (m, 26 arom. H); 7.50 (d, J=9.46, 2 Hf). 13C-NMR (125 MHz, CDCl3): 119.32; 125.42;
127.55; 128.04; 128.06; 128.15; 128.32; 128.96; 130.20; 131.21; 133.52; 137.95; 140.77; 151.20; 153.26;
160.82 (C=N). Anal. calc. for C42H32N2: C 89.33, H 5.71, N 4.96; found: C 89.35, H 5.75, N 4.97.

Helvetica Chimica Acta – Vol. 89 (2006)
283
Bis[N-(3,3-diphenylallylidene)quinolin-8-amine-kN,kN8]copper(1+)
Tetraphenylborate(1ꢀ)
([CuI(dpa-qa)2]BPh4; 1). To
a
soln. of L1 (33.4 mg, 0.1 mmol) in MeCN (5 ml) was added
[Cu(MeCN)4]BPh4 (27.4 mg, 0.05 mmol) in MeCN (5 ml), and stirring was continued for 10 min. The
soln. turned dark red rapidly. Then soln. was concentrated to ca. 4 ml. The diffusion of Et2O vapor
into the conc. soln. gave dark-red crystals which were filtered off and washed with Et2O/MeCN 9 :1,
and dried under vacuum: 90 mg (85%) of 1. IR (KBr): 1576 (C=N). 1H-NMR (500 MHz, CDCl3):
6.64–7.56 (m, 50 arom. H); 7.82 (d, J=9.46, 2 He); 8.22 (d, J=8.28, 2 Hc); 8.53 (d, J=9.46, 2 Hd); 8.61
(d, J=3.46, 2 Ha). 13C-NMR (125 MHz, CDCl3): 117.16; 121.52; 123.69; 125.44 (q, J(B,C)=2.75, Co of
BPh4); 126.37; 127.83; 127.93; 128.04; 128.37; 128.55; 128.72; 129.59; 130.19; 130.43; 136.33; 137.34;
137.64; 139.57; 142.62; 143.36; 150.05; 157.98; 164.10 (q, J(B,C) =49.75, Cipso of BPh4); 164.89 (C=N).
Anal. calc. for C72H56BCuN4: C 82.23, H 5.37, N 5.33; found: C 82.25, H 5.39, N 5.30.
Bis[N,N’-bis(3,3-diphenylallylidene)-[1,1’-biphenyl]-2,2’-diamine-kN,kN’]copper(1+)
Perchlorate
Water (1:1:3) ([CuI(bdpa-bda)2]ClO4 ·3 H2O; 2). To a soln. of L2 (56.7 mg, 0.1 mmol) in MeCN (5 ml)
was added [Cu(MeCN)4]ClO4 (16.4 mg, 0.05 mmol) in MeCN (3 ml), and stirring was continued for 10
min. The colorless soln. turned deep orange. Then the soln. was concentrated to ca. 1 ml. Slow evapora-
tion of the solvent gave dark-red crystals suitable for X-ray studies. The crystals were filtered off, washed
with a mixture of Et2O/MeCN 9 :1, and dried under vacuum: 55 mg (85%) of 2. IR (KBr): 1590 (C=N),
1085 (ClꢀO). 1H-NMR (500 MHz, CDCl3): 6.46–7.38 (m, 4 Hg, 56 arom. H); 7.89 (d, J=9.69, 4 Hf). 13C-
NMR (125 MHz, CDCl3): 121.04; 125.34; 127.29; 128.17; 128.28; 128.46; 129.14; 129.93; 129.98; 130.05;
132.06; 132.90; 136.72; 139.90; 150.03; 158.20; 163.48 (C=N). Anal. calc. for C84H70ClCuN4O7: C 74.93, H
5.24, N 4.16; found: C 75.10, H 5.31, N 4.10.
3. X-Ray Analysis. Crystals of 1 and 2 suitable for X-ray were obtained as described above. The crys-
tals were mounted on glass fibers. Diffraction data were collected on a Siemens-Smart-CCD diffractom-
eter by using graphite-monochromated MoKa radiation (l 0.71073 Å), a nominal crystal-to-detector dis-
tance of 4.40 cm, and 0.38 w-scan frames. Crystal data and the details of the structure determinations are
given in Table 2. The data were corrected for Lorentz and polarization effects, and an empirical absorp-
tion correction (SADABS [38]) was applied. The structure was solved by direct methods (SHELXS-86
[39]). The structure refinement was performed by a full-matrix least-squares method against F2
(SHELXL-93 [40]). All non-H-atoms were refined anisotropically, all H-atoms were inserted in calcu-
lated positions. Compound 2 shows a relatively large index R1 and wR2 on all data which is due to the
large amount of weak data that was not used in the refinement.
CCDC-278696 for 1 and -278697 for 2 contain the supplementary crystallographic data (excluding
structure factors) for this paper. These data can be obtained free of charge from the Cambridge Crystallo-
graphic Data Center via http://www.ccdc.cam.ac.uk/data_request/cif.
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Received August 22, 2005