Electrochemical synthesis of cobalt, nickel, copper, zinc and cadmium complexes with N[(2-hydroxyphenyl)methylidine]-N′-tosylbenzene-1,2-diamine. The crystal structures of {(1,10-phenanthroline)[N-(2-oxophenyl)methylidine]-N-tosylbenzene-1,2-diaminato} nickel(II) and {(1,10-phenanthroline)[N-(2-oxophenyl)methylidine]-N′-tosylbenzene-1,2- diaminato}copper(II)

Article abstract of DOI:10.1016/s0020-1693(99)00304-7

The electrochemical oxidation of cobalt, nickel, copper, zinc or cadmium anodes in an acetonitrile solution containing N[(2-hydroxyphenyl)methylidine]-N′-tosylbenzene-1,2-diamine (H₂L) yielded compounds of general formula [ML]. When 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) is added to the cell, mixed ligand complexes are obtained. The crystal structures of {(1,10-phenanthroline)[N-(2-oxophenyl)methylidine]-N′-tosylbenzene-1,2- diaminato}nickel(II) (1) and {(1,10-phenanthroline)[N-(2-oxophenyl)methylidine]-N′-tosylbenzene-1,2- diaminato}copper(II) (2) were determined by X-ray diffraction. Compound 1 consists of a binuclear [Ni₂L₂¹(phen)₂] complex with phenolic oxygen atoms bridging both nickel atoms. Each nickel atom is in a distorted octahedral [NiN₄O₂] environment. Compound 2 is monomeric, with the copper atom in a [CuN₄O] distorted square pyramidal geometry. The electronic, IR and NMR spectra of the complexes are discussed and related to the structure.

Full text of DOI:10.1016/s0020-1693(99)00304-7

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 295 (1999) 39–47
Electrochemical synthesis of cobalt, nickel, copper, zinc and
cadmium complexes with N[(2-hydroxyphenyl)methylidine]-
N%-tosylbenzene-1,2-diamine. The crystal structures of {(1,10-
phenanthroline)[N-(2-oxophenyl)methylidine]-N-tosylbenzene-1,2-
diaminato}nickel(II) and {(1,10-phenanthroline)[N-(2-oxophenyl)-
methylidine]-N%-tosylbenzene-1,2-diaminato}copper(II)
Mar Bernal a, Jose´ A. Garc´ıa-Va´zquez a, Jaime Romero a, Cristina Go´mez a,
Mar´ıa L. Dura´n a, Antonio Sousa a,*, Antonio Sousa-Pedrares a, David J. Rose b,
Kevin P. Maresca b, Jon Zubieta b
a Departamento de Qu´ımica Inorga´nica, Uni6ersidad de Santiago de Compostela, 15706 Santiago de Compostela, Spain
b Department of Chemistry, Syracuse Uni6ersity, Syracuse, NY 13244, USA
Received 8 March 1999; accepted 28 June 1999
Abstract
The electrochemical oxidation of cobalt, nickel, copper, zinc or cadmium anodes in an acetonitrile solution containing
N[(2-hydroxyphenyl)methylidine]-N%-tosylbenzene-1,2-diamine (H2L) yielded compounds of general formula [ML]. When 1,10-
phenanthroline (phen) or 2,2%-bipyridine (bipy) is added to the cell, mixed ligand complexes are obtained. The crystal structures
of {(1,10-phenanthroline)[N-(2-oxophenyl)methylidine]-N%-tosylbenzene-1,2-diaminato}nickel(II) (1) and {(1,10-phenanthroline)-
[N-(2-oxophenyl)methylidine]-N%-tosylbenzene-1,2-diaminato}copper(II) (2) were determined by X-ray diffraction. Compound 1
1
consists of a binuclear [Ni2L2 (phen)2] complex with phenolic oxygen atoms bridging both nickel atoms. Each nickel atom is in
a distorted octahedral [NiN4O2] environment. Compound 2 is monomeric, with the copper atom in a [CuN4O] distorted square
pyramidal geometry. The electronic, IR and NMR spectra of the complexes are discussed and related to the structure. © 1999
Elsevier Science S.A. All rights reserved.
Keywords: Crystal structures; Electrochemistry; Cobalt complexes; Copper complexes; Amide complexes
pyrrole [7–13] groups have been synthesised starting
with the metal as the anode of an electrolytic cell
1. Introduction
containing the ligand in an appropriate solvent. In
The application of electrochemical procedures to the
addition to its simplicity and high yield, the method
preparation of metal complexes of ligands having acid
allows the one-step preparation of mixed complexes
groups has been extensively investigated [1]. Com-
by addition of a second ligand to the cell. This paper
pounds with Schiff bases containing phenol [2–6] or
is an extension of our previous work on the electro-
chemical synthesis of complexes with Schiff bases con-
taining phenol and tosyl amide as acid groups, shown
below.
* Corresponding author. Tel.: +34-981-563 100; fax: +34-981-
597 525.
0020-1693/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(99)00304-7

40
M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
The Schiff bases were prepared by direct reaction of
equimolar amounts of the aldehyde and N-tosyl-1,2-di-
aminobenzene in ethanol using a Dean–Stark trap. Af-
ter removal of the water produced in the reaction, the
solution was concentrated and the isolated solid was re-
crystallised from ethanol. Its purity was checked by
1
recording its IR and H NMR spectra.
2.1. Electrochemical synthesis
An acetonitrile solution of the ligand containing about
15 mg of tetramethylammonium perchlorate as a current
carrier was electrolysed using a platinum wire as the
cathode and a metal plate as the anode. The cell can be
summarised as: Pt(−)/LH2+CH3CN/M(+), where
H2L stands for the Schiff bases and M represents the
metal. When mixed complexes were prepared, the corre-
sponding additional ligand was added to the electro-
chemical cell. When a crystalline solid was obtained after
the electrochemical reaction, the product was filtered in
vacuo using a sintered funnel, washed with acetonitrile
and diethyl ether, and dried. In those cases where no
solid was produced after the electrochemical reaction,
the solution was filtered and the filtrate was slowly evap-
orated at room temperature or on a vacuum line until a
solid was crystallised. The solution composition and the
experimental conditions are given in Table 1.
H2L1
H
H2L2
(3,5)-Br2
H2L3
5-Cl
R
2. Experimental
Acetonitrile, 2-hydroxybenzaldehyde, 1,2-diamino-
benzene, and all other reagents were commercial prod-
ucts and were used as supplied. Metals (Ega Chemie)
were used as plates (approximately 2×2 cm2).
N-tosyl-1,2-diaminobenzene was prepared by the re-
action of a solution of o-phenylenediamine (5 g, 46.3
mmol) in pyridine (30 cm3) and p-toluenesulphonyl chlo-
ride (9 g, 47.5 mmol) in an ice-bath with continuous
magnetic stirring. The reaction mixture was then poured
into cold water (60 cm3) with stirring affording a black
oil in the bottom of the flask. The oil was isolated and
treated with a hot 1:1 ethyl alcohol 95%–water mixture.
After cooling, the solid obtained was recrystallised in 1:1
ethyl alcohol–water affording a white spongy com-
pound. Yield: 8.9 g, 77.5%, m.p. 135–136°C.
2.2. Physical measurements
The C, N, H and S contents of the complexes were
determined on a Perkin–Elmer 240B microanalyser. IR
Table 1
Experimental conditions for the synthesis of complexes a
Compound
Amount of H2L (g) b
Amount of L% (g)
Time (h)
Metal dissolved (mg)
Ef (mol F−1
)
[CoL1]
0.154
0.154
0.154
0.154
0.200
0.200
0.200
0.305
0.200
0.200
0.305
0.200
0.140
0.200
0.200
0.140
0.383
0.200
0.200
–
–
2
2
4
2
2
1.5
2
3
1.2
1
3
1.5
2
2
3
2
4
2
3
22.5
23.2
46.1
22.8
22.3
37.1
47.2
70.3
30.2
22.4
74.3
40
24.2
24.0
36
42.2
89.4
39.5
60
0.51
0.53
0.52
0.51
0.49
1.04
0.99
0.98
1.06
0.95
1.04
1.12
0.49
0.49
0.49
0.50
0.53
0.47
0.48
[CoL2]
[NiL1(phen)]
[NiL2(phen)]
[NiL2(bipy)]
[CuL1]
0.230
0.430
0.230
–
0.180
0.150
–
0.240
0.110
–
–
–
–
–
[CuL1(bipy)]
[CuL1(phen)]
[CuL2]
[CuL2(bipy)]
[CuL2(phen)]
[CuL3]
[ZnL1]
[ZnL2]
[ZnL3]
[CdL1]
[CdL1(phen)]
[CdL2]
0.210
–
–
[CdL3]
a Intensity of current 10 mA.
b Plus [NMe4]ClO4 (approximately 10 mg).

M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
41
Table 2
spectra were recorded as KBr mulls on a Perkin–Elmer
130 spectrophotometer. The 1H NMR spectra were
Summary of crystal data for [Ni2L21(phen)2] (1) and [CuL1(phen)] (2)
recorded on
a Bruker WM 350 MHz spectro-
[Ni2L21(phen)2]
[CuL1(phen)]
photometer, using DMSO-d6 as solvent. Chemical
shifts were referenced to TMS as internal standard. The
electronic spectra in the solid were recorded on a
Hitachi 4-3200 spectrophotometer.
Empirical Formula
Formula weight
Size
Crystal system
Space group
C
1287.4
0.12×0.10×0.10
triclinic
P1
68H54N10O6S2Ni2 C32H24CuN4O3S
608.15
0.50×0.25×0.15
triclinic
(
(
P1
Unit cell dimensions
2.3. Crystal structure determination
,
a (A)
11.06530(10)
13.13320(10)
21.08370(10)
93.0930(10)
97.1830(10)
100.6370(10)
2978.32(4)
2
1.437
0.71073
0.766
293(2)
8.840(2)
9.972(2)
15.813(5)
104.36(3)
87.44(3)
99.13(3)
1333.3(5)
2
1.515
0.71073
0.941
293(2)
2278
2082
,
b (A)
The data collection was carried out on a Rigaku
AFC5S for 1 and on an Enraf–Nonius CAD4 for
2, using graphite-monochromatised Mo Ka radiation,
,
c (A)
h (°)
i (°)
k (°)
,
u=0.71073 A, 293 K. The ꢀ/2q scan technique
3
,
V (A )
was employed to measure the intensities for 18 455 and
2278 reflections up to a maximum Bragg angle of 28.27
and 22.46° for 1 and 2, respectively. Cell parameters
were refined by a least-squares procedure on setting
angles of 25 reflections. No decomposition of the crys-
tal occurred during the data collection. Corrections
were applied for Lorentz and polarisation effects and
for absorption (v=0.776 and 0.941 mm−1 for 1 and 2)
[14].
Z
Dcalc (g cm−3
)
,
u (A) (Mo Ka radiation)
v (mm−1) (Mo Ka)
T (K)
No. reflections collected
No. independent reflections 12 923
18 455
F(000)
1336
0.074
0.194
626
0.0214
0.0570
a
R
b
Rw
The structures were solved by direct methods and
refined by a full-matrix least-squares procedure based
on F2. Non-hydrogen atoms were refined with an-
isotropic displacement parameters. The structural disor-
der of the acetonitrile molecules explains the high
values of the R factor in the case of the nickel com-
pound. The atomic scattering factors were taken from
International Tables for X-ray Crystallography [15].
The calculations were carried out on a Micro VAXII
using the crystallographic software TEXSAN [16] for 1
and SHELX86 [17] for 2. The crystal parameters and
other experimental details of data collection and refine-
ment are summarised in Table 2.
a R=ꢀ(ꢁFoꢁ−ꢁFcꢁ)/ꢀꢁFoꢁ.
2 1/2
b Rw=[(ꢀw(ꢁFoꢁ−ꢁFcꢁ)2/ꢀwꢁFoꢁ ]
.
Cathode:
Anode:
H2L+e−“HL−+1/2H2
Cu“Cu++e−
Cu++HL−“[CuL]+1/2H2
In the case of cobalt, nickel, zinc and cadmium
complexes, the electrochemical efficiency is close to
Table 3
Analytical data for complexes (%) a
Compound
%C
%H
%N
6.2(6.6)
4.8(4.8)
10.9(10.5)
%S
[CoL1]
56.5(56.7)
41.2(41.3)
64.2(64.7)
3.6(3.8)
2.7(2.4)
4.1(4.1)
7.2(7.5)
5.3(5.5)
5.1(4.8)
3. Results and discussion
[CoL2]
[NiL1(phen)]·
CH3CN
The analytical results of Table 3 show that the elec-
trochemical procedure is an effective method for ob-
taining compounds of general formula [ML], where M
is cobalt, nickel, copper, zinc and cadmium and L
stands for the dianionic form of the Schiff bases. When
the synthesis was carried out in presence of additional
ligands (1,10-phenanthroline or 2,2%-bipyridine), mixed
complexes of general formula [ML(phen)] or [ML-
(bipy)] were obtained.
[NiL2(bipy)]
[NiL2(phen)]
[CuL1]
48.4(48.9)
52.2(51.9)
56.4(56.1)
61.7(61.7)
64.3(64.6)
41.3(40.9)
48.4(48.4)
50.2(50.2)
51.9(51.9)
55.5(55.9)
40.7(40.7)
52.1(51.7)
50.2(50.4)
59.8(59.9)
37.2(37.7)
46.7(46.9)
3.0(3.1)
2.8(3.0)
3.9(3.8)
3.7(4.1)
3.3(3.8)
3.0(2.6)
3.0(3.2)
2.9(3.0)
3.4(3.5)
3.9(3.8)
3.0(2.7)
3.2(3.1)
3.3(3.4)
3.6(3.6)
2.9(2.5)
2.7(3.1)
7.4(7.6)
7.4(7.1)
6.3(6.6)
9.4(9.6)
9.4(8.9)
4.5(4.8)
8.0(7.5)
7.8(7.3)
6.5(6.0)
6.5(6.5)
4.9(4.8)
6.0(6.0)
6.0(5.9)
8.6(8.2)
4.5(4.4)
5.3(5.4)
3.9(4.3)
4.2(4.1)
7.2(7.5)
5.5(5.5)
5.8(5.1)
4.7(5.4)
4.4(4.3)
4.4(4.2)
6.9(6.9)
7.3(7.5)
4.7(5.4)
6.9(6.8)
6.4(6.7)
4.2(4.7)
5.4(5.0)
6.3(6.2)
[CuL1(bipy)]
[CuL1(phen)]
[CuL2]
[CuL2(bipy)]
[CuL2(phen)]
[CuL3]
[ZnL1]
In the case of copper complexes, the electrochemical
efficiency was close to 1.0 mol F−1. This value
is indicative of the formation of Cu+ at the anode,
which is subsequently oxidised to Cu2+ in solution.
This fact together with the H2 evolution at the cath-
ode are compatible with the following reaction
scheme:
[ZnL2]
[ZnL3]
[CdL1]
[CdL1
(phen)]
[CdL2]
[CdL3]
a Calculated values in parentheses.

42
M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
Fig. 1. Molecular structure of [Ni2L21(phen)2] (1).
0.5 mol F−1. This is in accordance with the following
reaction mechanism:
of 180°. (N(1)ꢀNi(1)ꢀO(1)=164.1(2)°, N(8)ꢀNi(2)ꢀ
O(1)=164.5(2)°, N(7)ꢀNi(2)ꢀN(6)=175.4(2)°, O(4)ꢀ
Ni(1)ꢀN(4)=164.0(2)°, N(5)ꢀNi(2)ꢀO(4)=165.5(2)°,
N(2)ꢀNi(1)ꢀN(3)=173.3(2)°). The angles defined by
the nickel atom and the two cis-donor atoms are also
different from 90°, particularly in the case of the chelate
ring, N(7)ꢀNi(2)ꢀN(8)=79.3(2)°, N(5)ꢀNi(2)ꢀN(6)=
Cathode:
Anode:
H2L+2e−“L2−+H2
M+L2−“[ML]+2e−
1
3.1. Molecular structure of [Ni2L2 (phen)2]·2CH3CN
(1)
79.0(2)°,
N(1)ꢀNi(1)ꢀN(2)=78.9(2)°,
N(3)ꢀNi(1)ꢀ
N(4)=78.8(2)°. The NiꢀN amide bond distances,
Fig. 1 shows the molecular structure of 1 together
with the atom labelling scheme used. Final atomic
coordinates, bond distances and angles are given in
Tables 4 and 5, respectively.
,
2.138(5) and 2.131(5) A, are longer than the NiꢀN
imine bond distances and longer than that in the binu-
clear hexacoordinated nickel(II) complex {bis-
(methanol)[2-(2-N-tosylaminophenyl)
iminomethyl]
1
The structure consists of dimeric [Ni2L2 (phen)2]
,
phenolato}nickel(II) [18] of 2.093(13) A. This distance
molecules with both metal atoms bridged by phenolic
oxygen atoms. This bridge is slightly asymmetric, with
is also longer than those found in tetrahedral amide
,
Ni(II) complexes (1.916(3) [19] and 1.839(6) A [20]), a
,
bond lengths O(1)ꢀNi(1) 2.135(4) A, O(4)ꢀNi(2)
feature reflecting the lower coordination number in the
tetrahedral complexes.
,
,
2.152(4) A and O(1)ꢀNi(2) 2.064(4) A, O(4)ꢀNi(1)
,
2.083(4) A. The four-membered ring formed by the two
nickel atoms and the oxygen bridging atoms is not
The NiꢀNimine bond distances, 2.042(4) and 2.030(4)
,
A, are similar to those found in other hexacoordinated
planar
(angle
between
Ni(1)ꢀO(1)ꢀO(4)
and
nickel(II) salicylaldiminate complexes [4,21]. The two
Ni(2)ꢀO(1)ꢀO(4) of 3.60(20)°). The coordination sphere
around each metal is completed by the amide and the
imino nitrogen atoms of the Schiff base and the two
nitrogen atoms of the bidentate 1,10-phenanthroline.
Each nickel atom is in a [NiN4O2] distorted octahe-
dral environment with the donors of the terdentate
Schiff base in a meridional disposition. The angles
defined by the two trans-donor atoms and the nickel
atom are significantly different from the idealised value
NiꢀNphen bond distances are non-equivalent, 2.134(5)
,
,
and 2.087(4) A for Ni(1) and 2.132(5) and 2.084(5) A
for Ni(2), but similar to those found in other Ni(II)
hexacoordinated complexes with 1,10-phenanthroline,
2+
,
2.06(4) and 2.15(3) A [22] in [Ni(phen)3]
[24] or
,
2.125(5) and 2.136(5) A in 1,10-phenanthroline-bis{[2-
(2 - pyrrole)methyleneimino]4 - methylphenolato}nic-
kel-(II) [23].

M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
43
Table 4
Atomic coordinates (×104] for [NiL1(phen)]2·2CH3CN (1)
Table 4 (continued)
C(43)
C(44)
C(45)
C(46)
C(47)
C(48)
C(49)
C(50)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
C(58)
C(59)
C(60)
C(61)
C(62)
C(63)
C(64)
C(65)
C(66)
C(67)
C(68)
3161(6)
4203(5)
3400(5)
4006(5)
4824(6)
5094(7)
4539(6)
3685(5)
3060(6)
1652(6)
1335(7)
646(8)
528(4)
139(4)
708(5)
1708(5)
1822(6)
960(3)
1276(3)
3142(3)
3415(3)
3978(4)
4284(3)
4025(3)
3454(3)
3252(3)
2601(3)
3083(3)
2943(4)
2310(4)
1819(3)
1945(3)
708(3)
39(1)
39(1)
37(1)
45(1)
59(2)
62(2)
53(2)
40(1)
42(1)
40(1)
50(2)
63(2)
64(2)
51(2)
42(1)
41(1)
63(2)
69(2)
61(2)
60(2)
47(1)
97(4)
59(8)
60(8)
27(4)
26(4)
x
y
z
Ueq
Ni(1)
Ni(2)
S(1)
S(2)
O(1)
O(2)
O(3)
O(4)
O(5)
737(1)
2115(1)
1528(2)
1430(2)
2540(3)
2682(5)
1307(6)
288(3)
817(1)
−641(1)
2977(1)
2814(1)
1964(1)
3815(1)
757(1)
2631(2)
4213(3)
3195(2)
2106(2)
473(2)
32(1)
31(1)
46(1)
43(1)
35(1)
65(1)
64(1)
35(1)
61(1)
57(1)
37(1)
36(1)
35(1)
40(1)
38(1)
38(1)
37(1)
39(1)
69(8)
46(5)
45(1)
52(2)
56(2)
45(1)
60(2)
61(2)
46(1)
55(2)
54(2)
44(1)
36(1)
36(1)
36(1)
46(1)
56(2)
67(2)
58(2)
42(1)
41(1)
38(1)
50(2)
57(2)
59(2)
52(2)
42(1)
49(2)
70(2)
80(3)
66(2)
67(2)
61(2)
89(3)
49(2)
61(2)
63(2)
67(2)
53(2)
67(2)
53(2)
64(2)
58(2)
48(1)
959(7)
−13(6)
−2542(1)
627(3)
−169(5)
−1222(5)
−2557(4)
−3194(5)
−4187(5)
−4532(6)
−3899(5)
−2894(5)
−3506(5)
−3317(6)
−4058(7)
−4996(6)
−5165(5)
−4421(5)
−5827(8)
4346(28)
3397(29)
−4877(12)
−5457(14)
3451(4)
3378(4)
−412(3)
−3061(4)
−1676(4)
1111(4)
1915(3)
−278(4)
1744(4)
−473(4)
245(4)
−1514(4)
−2167(4)
2768(22)
−5891(16)
774(5)
1104(6)
1790(6)
2150(5)
2850(6)
3187(6)
2913(5)
3347(5)
3100(5)
2371(5)
2202(4)
1788(4)
−1227(4)
−1800(5)
−2682(6)
−3044(6)
−2499(6)
−1598(5)
−1135(5)
46(5)
190(5)
1988(5)
O(6)
426(2)
249(8)
524(7)
N(1)
N(2)
N(3)
N(4)
N(5)
N(6)
N(7)
N(8)
N(9)
N(10)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(37)
C(38)
C(39)
C(40)
C(41)
C(42)
−1107(4)
817(4)
2727(2)
2134(2)
3458(2)
3702(2)
1763(2)
1175(2)
2722(2)
1498(2)
6356(17)
2408(11)
3065(3)
2983(3)
2533(4)
2156(3)
1664(4)
1332(4)
1480(3)
1210(3)
1430(3)
1895(3)
1949(3)
2282(3)
2129(3)
1558(3)
1559(4)
2127(4)
2702(4)
2716(3)
3342(3)
4096(3)
4565(3)
5165(3)
5298(3)
4840(3)
4223(3)
4239(3)
3900(4)
4228(5)
4895(4)
5220(4)
4900(4)
5240(5)
2037(3)
1826(4)
1344(4)
543(4)
1228(6)
2377(6)
3560(7)
4305(7)
3884(8)
2716(8)
1961(6)
4682(10)
4326(27)
4534(23)
3404(15)
4416(17)
439(4)
1323(5)
3979(4)
2048(5)
2320(4)
1557(5)
1058(4)
1032(5)
666(4)
313(4)
337(3)
4660(23)
5049(19)
−2010(6)
−3165(6)
−3369(6)
−2430(6)
−2574(7)
−1643(7)
−438(6)
607(7)
667(6)
5793(13)
6086(15)
2631(10)
2521(9)
The NiꢀO bond distances, 2.135(4), 2.083(4), 2.064(4)
and 2.152(4) A, are longer than those observed in
mononuclear salicylaldiminate hexacoordinated nick-
el(II) complexes (2.005(4) and 2.032(3) A) [4,21,24] and
display a relatively large range. The shorter bond
lengths are similar to the values found in {bis-
(methanol)[2-(2-N-tosylaminophenyl)iminomethyl] phe-
,
1730(7)
1803(6)
,
−283(5)
−1310(5)
−608(5)
−1212(6)
−2100(6)
−2451(7)
−1885(7)
−963(6)
−356(6)
1029(5)
,
nolato}nickel(II), 2.051(11) and 2.063(10) A [18].
The phenyl rings of the dianionic Schiff base ligand
are planar. The 1,10-phenanthroline ligand is also es-
sentially planar with bond distances and angles similar
to those of other phenanthroline complexes. The
NimineꢀC bond distances have the expected values for a
1198(6)
1805(7)
2282(7)
2152(7)
1514(6)
325(7)
−655(5)
−307(6)
746(7)
,
(CꢁN) azomethine bond [25]: N(3)ꢀC(19)=1.285(7) A
1453(6)
1117(5)
3251(5)
3250(7)
3433(8)
3643(6)
3674(7)
3484(6)
3852(9)
−906(5)
−756(7)
−143(7)
1016(6)
355(6)
,
and N(3)ꢀC(19)=1.295(8) A. The CꢀO distances are
shorter than expected for a single bond, but longer than
for a CꢁO double bond [26].
−822(8)
−1797(8)
−1606(8)
−443(8)
526(8)
3.2. Molecular structure of [CuL1(phen)] (2)
Fig. 2 shows the molecular structure of 2 together
with the labelling scheme used. Final atomic coordi-
nates, bond distances and angles are given in Tables 6
and 7, respectively.
In 2, the copper atom is pentacoordinated by the
imine nitrogen atom, the amide group nitrogen atom
and the phenolic oxygen atom of the dianionic Schiff
base and the nitrogen atoms of phenanthroline. A
comparison of the metrical parameters of 2 given in
Table 4 with the ideal values for the limiting coordina-
−2681(9)
4901(6)
6068(6)
6298(7)
5522(8)
5371(7)
4562(9)
3314(8)
2264(9)
1145(8)
1052(3)
252(3)
1398(6)
1143(5)
1456(6)
1140(5)
537(5)
437(3)
130(3)
330(3)
863(3)
1076(7)

44
M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
Table 5
,
[28], or 1.944(7) and 1.957(6) A in 1,10-phenanthro-
line{2-[(2-oxyphenyl)iminomethyl]phenolato}copper(II)
Selected bond distances and angles for [NiL1(phen)]2·2CH3CN (1)
,
[29]. Similarly, the CuꢀNimine bond distance, 1.940(3) A,
Bond lengths
conforms to that found in the above complexes with
Ni(1)ꢀN(3)
Ni(1)ꢀN(2)
Ni(1)ꢀO(1)
Ni(2)ꢀN(7)
Ni(2)ꢀN(6)
Ni(2)ꢀN(8)
S(1)ꢀO(3)
S(1)ꢀN(4)
S(2)ꢀO(6)
S(2)ꢀN(8)
O(1)ꢀC(45)
N(l)ꢀC(1)
N(2)ꢀC(10)
N(3)ꢀC(19)
N(4)ꢀC(25)
N(5)ꢀC(44)
N(6)ꢀC(43)
N(7)ꢀC(52)
N(9)ꢀC(66)
2.042(4)
2.087(4)
2.135(4)
2.030(4)
2.084(5)
2.131(5)
1.444(5)
1.594(5)
1.448(5)
1.595(5)
1.331(6)
1.323(7)
1.316(7)
1.285(7)
1.425(8)
1.351(8)
1.360(8)
1.424(8)
1.05(4)
Ni(1)ꢀO(4)
Ni(1)ꢀN(1)
Ni(1)ꢀN(4)
Ni(2)ꢀO(1)
Ni(2)ꢀN(5)
Ni(2)ꢀO(4)
S(1)ꢀO(2)
2.083(4)
2.134(5)
2.138(5)
2.064(4)
2.132(5)
2.152(4)
1.452(6)
1.773(7)
1.453(5)
1.793(6)
1.326(7)
1.354(7)
1.357(7)
1.426(7)
1.342(8)
1.318(8)
1.295(8)
1.410(7)
1.02(3)
,
average values of 1.946 and 1.93(1) A, respectively.
The bond distances between the copper atom and the
two nitrogen atoms of the 1,10-phenanthroline
molecule are significantly different at 2.028(3) and
2.320(3) A, with the longer distance associated with the
apical nitrogen atom. The value of 2.028(3) A can be
considered as normal and similar to those found in
other copper complexes with bidentate 1,10-phenan-
throline or 2,2%-bipyridine ligands [30,31]. However, the
,
,
S(1)ꢀC(26)
S(2)ꢀO(5)
S(2)ꢀC(58)
O(4)ꢀC(13)
N(1)ꢀC(12)
N(2)ꢀC(11)
N(3)ꢀC(20)
N(5)ꢀC(33)
N(6)ꢀC(42)
N(7)ꢀC(51)
N(8)ꢀC(57)
N(10)ꢀC(68)
,
2.320(3) A value is unusually high and similar to the
longest CuꢀN distance found in [Cu(phen)3]2+ [31], a
Table 6
Atomic coordinates (×104) for [CuL1(phen)] (2)
x
y
z
Ueq
Bond angles
N(3)ꢀNi(1)ꢀO(4)
O(4)ꢀNi(1)ꢀN(2)
O(4)ꢀNi(1)ꢀN(1)
N(3)ꢀNi(1)ꢀO(1)
N(2)ꢀNi(1)ꢀO(1)
N(3)ꢀNi(1)ꢀN(4)
N(2)ꢀNi(1)ꢀN(4) 103.2(2)
O(1)ꢀNi(1)ꢀN(4) 96.8(2)
N(7)ꢀNi(2)ꢀN(6) 175.4(2)
N(7)ꢀNi(2)ꢀN(5)
N(6)ꢀNi(2)ꢀN(5)
O(1)ꢀNi(2)ꢀN(8) 164.5(2)
N(5)ꢀNi(2)ꢀN(8) 94.1(2)
86.7(2)
92.0(2)
93.7(2)
99.0(2)
87.2(2)
78.8(2)
N(3)ꢀNi(1)ꢀN(2) 173.3(2)
Cu
S
O(1)
O(2)
2174(1)
4684(1)
4867(3)
5444(2)
1335(3)
2252(3)
4150(3)
224(3)
2937(3)
1374(5)
1628(5)
2822(5)
3802(4)
5072(5)
5982(5)
5728(4)
6696(4)
6374(5)
5091(4)
4470(4)
3465(4)
1517(1)
−48(1)
3335(1)
2083(1)
1407(2)
2890(1)
4466(2)
2567(2)
3742(2)
2935(2)
2303(2)
1962(3)
1591(3)
1870(3)
2512(2)
2856(3)
3457(3)
3769(2)
4372(2)
4624(3)
4302(2)
3466(2)
2832(2)
4318(2)
4796(2)
5685(2)
6083(3)
5618(3)
4755(2)
3416(2)
2041(2)
1698(2)
821(2)
27(1)
27(1)
36(1)
32(1)
37(1)
31(1)
25(1)
25(1)
26(1)
42(1)
49(1)
45(1)
34(1)
42(1)
40(1)
30(1)
36(1)
35(1)
29(1)
25(1)
27(1)
27(1)
28(1)
37(1)
37(1)
37(1)
33(1)
28(1)
27(1)
26(1)
38(1)
42(1)
43(1)
37(1)
29(1)
40(1)
49(1)
49(1)
47(1)
37(1)
87(2)
N(3)ꢀNi(1)ꢀN(1)
N(2)ꢀNi(1)ꢀN(1)
O(4)ꢀNi(1)ꢀO(1)
94.6(2)
78.9(2)
78.94(14)
−1279(2)
89(2)
2314(2)
3230(3)
2815(3)
391(3)
N(1)ꢀNi(1)ꢀO(1) 164.1(2)
O(4)ꢀNi(1)ꢀN(4) 164.0(2)
O(3)
N(1)
N(2)
N(3)
N(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
N(1)ꢀNi(1)ꢀN(4)
N(7)ꢀNi(2)ꢀO(1)
O(1)ꢀNi(2)ꢀN(6)
O(1)ꢀNi(2)ꢀN(S)
N(7)ꢀNi(2)ꢀN(8)
94.0(2)
86.2(2)
94.5(2)
92.9(2)
79.3(2)
100(3)
96.4(2)
79.0(2)
3391(4)
4537(4)
5560(5)
5446(3)
6465(4)
6285(4)
5030(3)
4775(4)
3555(4)
2611(4)
4018(3)
4231(3)
838(3)
1870(3)
2412(4)
1951(4)
936(4)
406(4)
186(4)
−328(3)
−482(3)
−1180(4)
−1661(4)
−1478(4)
−815(4)
1432(3)
1713(4)
2891(4)
3821(4)
3531(4)
2338(4)
5144(7)
N(6)ꢀNi(2)ꢀN(8) 100.4(2)
N(7)ꢀNi(2)ꢀO(4)
N(6)ꢀNi(2)ꢀO(4)
N(8)ꢀNi(2)ꢀO(4)
95.0(2)
89.6(2)
96.8(2)
O(1)ꢀNi(2)ꢀO(4) 78.96(14)
N(5)ꢀNi(2)ꢀO(4) 165.5(2)
tion polyhedron, square pyramidal and trigonal bipyra-
mid, together with the value of 0.248 found for the
geometrical parameter, ~, defined as (i−h)/60, where
i and h represents the bond angles N(3)ꢀCuꢀN(2) and
O(3)ꢀCuꢀN(4), respectively, suggest that the complex
has a geometry closer to a square pyramid, ~=0, than
to a trigonal bipyramid, ~=1 [27].
The oxygen atom from the phenolato group, the
imine nitrogen atom and the amide nitrogen atom from
the Schiff base, and one of the 1,10-phenanthroline
nitrogen atoms are in the basal plane, with the second
1,10-phenanthroline nitrogen atom occupying the api-
cal position. The angles around the metal involving the
apical nitrogen atom are different from 90°, due to the
small bite of the phenanthroline ligand: N(1)ꢀCuꢀN(2),
76.63(11)°; N(1)ꢀCuꢀN(4), 93.98(10)°; N(1)ꢀCuꢀN(3),
99.83(11)° and N(1)ꢀCuꢀO(3), 104.76(10)°.
−1116(4)
34(4)
−276(5)
−1591(4)
−2693(5)
−2457(4)
−957(4)
267(4)
1736(4)
1833(5)
546(5)
−862(5)
−1018(5)
5498(4)
4855(5)
5435(5)
6640(5)
7287(5)
6722(4)
7260(11)
316(3)
653(3)
1514(3)
1690(2)
985(3)
707(3)
1124(3)
1823(3)
2108(3)
833(6)
,
The CuꢀO distance, 1.932(2) A, is not very different
from others found in pentacoordinated copper com-
plexes, for example 1.936 A, the average value for the
bis-(N-dimethylaminoethylsalicylaldiminato)copper(II)
,

M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
45
Fig. 2. Molecular structure of [CuL1(phen)] (2).
compound with a very pronounced Jahn–Teller distor-
tion. A similar behaviour is found in the case of 1,10-
phenanthroline{2 - [2 - (oxyphenyl)iminomethyl]pheno-
lato}copper(II) [29]. The CuꢀNamide bond length,
meric structures in the solid state, as the metallic atoms
would be in a coordinatively unsaturated tricoordinated
environment if the compounds were monomeric. The
spectra of the mixed complexes show bands of the
coordinated phenanthroline at 1510, 850 and 730 cm−1
[33], or bipyridine at 760 and 740 cm−1 [34].
,
2.044(3) A, is not different from that found in pentaco-
ordinated copper(II) complexes, i.e., 2.041(5) and
,
2.031(5) A in [CuL2dmf], with HL standing for N-(p-
The solid state electronic spectra of [CoL] show three
d–d bands at approximately 9000, 14 000 and 18 000
cm−1, which are in the expected range for hexacoordi-
nated cobalt(II) complexes [35] and can be assigned to
tolyl-sulphonyl)-o-phenylenediamine) [32]. The two
phenyl rings from the Schiff base, including the oxygen
donor atoms, are planar, and the 1,10-phenanthroline
molecule is also planar.
4
4
the transitions T1g“4T2g(w1), T1g“4A2g(w2) and
4T1g“4T1g(P)(w3), respectively. These data suggest a
3.3. Spectroscopic studies
Table 7
The IR spectra of the complexes show the absence of
the w(OH) and w(NH) bands which, in the free ligands,
appear in the 3100–2800 and 3250 cm−1 ranges, re-
spectively. This observation indicates that the phenol
hydrogen atom and the amide hydrogen atom are lost
during the electrochemical process. The band at-
tributable to w(CO) of the phenol group is shifted to
higher frequencies and the band assignable to the
azomethine group is shifted to lower frequencies upon
complexation. All these data suggest that the Schiff
bases are coordinated in the dianionic form through the
phenol oxygen atom and the amide and imine nitrogen
atoms, and exhibit the terdentate character of the lig-
ands in the complexes. This conclusion is supported by
1
,
Selected bond distances (A) and angles (°) for [CuL (phen)] (2)
Bond lengths
CuꢀO(3)
CuꢀN(2)
CuꢀN(1)
SꢀO(1)
1.936(2)
2.028(3)
2.320(3)
1.440(2)
1.778(3)
1.314(5)
1.314(4)
1.283(4)
1.413(4)
CuꢀN(3)
CuꢀN(4)
SꢀO(2)
SꢀN(4)
O(3)ꢀC(14)
N(1)ꢀC(12)
N(2)ꢀC(11)
N(3)ꢀC(20)
C(1)ꢀC(2)
1.940(3)
2.044(3)
1.434(2)
1.590(3)
1.300(4)
1.347(4)
1.361(4)
1.420(4)
1.394(5)
SꢀC(26)
N(1)ꢀC(1)
N(2)ꢀC(10)
N(3)ꢀC(19)
N(4)ꢀC(21)
Bond angles
O(3)ꢀCuꢀN(3)
O(3)ꢀCuꢀN(2)
O(3)ꢀCuꢀN(4)
N(2)ꢀCuꢀN(4)
N(3)ꢀCuꢀN(1)
N(4)ꢀCuꢀN(1)
92.34(11)
86.58(10)
160.97(10)
101.24(10)
99.83(11)
93.98(10)
N(3)ꢀCuꢀN(2)
N(3)ꢀCuꢀN(4)
O(3)ꢀCuꢀN(1)
N(2)ꢀCuꢀN(1)
O(2)ꢀSꢀO(1)
175.88(11)
81.00(11)
104.76(10)
76.63(11)
115.67(14)
112.74(14)
1
the X-ray diffraction structures of [Ni2L2 (phen)2] and
[CuL1(phen)]. Therefore, it is reasonable to propose for
complexes of general formulae [ML] dimeric or poly-
O(1)ꢀSꢀN(4)

46
M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
polymeric hexacoordinated structure for the cobalt
complexes.
References
[1] M.C. Chakravorti, G.V.B. Subrahmanyam, Coord. Chem. Rev.
135 (1994) 65.
The solid reflectance spectra of the [CuL] complexes
show a broad band around 16 000 cm−1 typical of
copper(II) species with a square-planar geometry [35].
This environment can be achieved by dimerisation of
the compound through the oxygen atom. The dimeric
nature of the compound could not be confirmed by
determination of the molecular weight for solubility
reasons. The solid reflectance spectra for the mixed
complexes [CuLL%] show bands around 10 500, 13 000
and 16 000 cm−1 in accordance with a pentacoordi-
nated geometry for these complexes [35], which is the
structure of [CuL1(phen)] as established by X-ray
diffraction.
[2] T. Sogo, J. Romero, A. Sousa, A. de Blas, M.L. Dura´n, E.E.
Castellano, Z. Naturforsch., Teil B 43 (1988) 611.
[3] N.M. Atherton, D.E. Fenton, G.J. Hewson, C.H. McLean, R.
Bastida, J. Romero, A. Sousa, E.E. Castellano, J. Chem. Soc.,
Dalton Trans. (1988) 1059.
[4] M.L. Dura´n, J.A. Garc´ıa-Va´zquez, A. Mac´ıas, J. Romero, A.
Sousa, E.B. Rivero, Z. Anorg. Allg. Chem. 573 (1989) 215.
[5] E. Labisbal, A. de Blas, J.A. Garc´ıa-Va´zquez, J. Romero, M.L.
Dura´n, A. Sousa, N.A. Bailey, D.E. Fenton, P.B. Leeson, R.V.
Parish, Polyhedron 11 (1992) 227.
[6] E. Labisbal, J.A. Garc´ıa-Va´zquez, J. Romero, A. Sousa, A.
Castin˜eiras, C. Maichle-Mo¨ssmer, U. Russo, Inorg. Chim. Acta
223 (1994) 87.
[7] J.A. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, A. Castin˜eiras,
M.L. Dura´n, A. Sousa, Z. Anorg. Allg. Chem. 615 (1992) 155.
[8] J.A. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, M.L. Dura´n, A.
Sousa, E.E. Castellano, J. Zukerman-Schpector, Polyhedron 11
(1992) 235.
The electronic spectra in the solid state for mixed
nickel(II) complexes [NiLL%] show bands at approxi-
mately 11 000 and 16 000 and between 20 300 and
26 500 cm−1 in accord with a hexacoordinated environ-
ment around the nickel atom [35]. We propose a binu-
clear structure for these complexes with the metallic
atoms hexacoordinated, through phenoxy groups acting
as bridging ligands, as found for the structure of
[9] J.A. Castro, J.E. Vilasa´nchez, J. Romero, J.A. Garc´ıa-Va´zquez,
M.L. Dura´n, A. Sousa, E.E. Castellano, J. Zukerman-Schpector,
Z. Anorg. Allg. Chem. 612 (1992) 83.
[10] J.A. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, A. Sousa, E.E.
Castellano, J. Zukerman-Schpector, Polyhedron 12 (1993) 31.
[11] J.A. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, A. Mac´ıas, A.
Sousa, U. Englert, Polyhedron 12 (1993) 1391.
1
[Ni2L2 (phen)2].
The 1H NMR spectra of the zinc and cadmium
complexes show no signals due to the hydrogen atoms
from the ꢀNH and ꢀOH groups, reinforcing the IR
conclusion that the ligands are coordinated to the metal
in its dianionic form. Furthermore, the signal of the
azomethine hydrogen atom is shifted towards lower
field, around 0.4–0.7 ppm, upon complexation. This
behaviour is a consequence of the coordination of the
imine nitrogen atom to the metal.
[12] J.A. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, A. Sousa, A.
Castin˜eiras, J. Chem. Crystallogr. 24 (1994) 7.
[13] J. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, M.L. Dura´n, A.
Castin˜eiras, A. Sousa, D.E. Fenton, J. Chem. Soc., Dalton
Trans. (1990) 3255.
[14] N. Walker, D. Stuart, Acta Crystallogr., Sect. A 39 (1983) 158.
[15] International Tables for X-ray Crystallography, vol. IV, Kynoch
Press, Birmingham, 1974.
[16] TEXSAN–TEXRAY Structure Analysis Package, Molecular Struc-
ture Corporation, 1985.
[17] G.M. Sheldrick, SHELX86: A Program for the Solution of Crystal
Structures from X-ray Diffraction Data, University of Go¨ttin-
gen, Go¨ttingen, Germany, 1986.
[18] A.S. Burlov, A.S. Antsyshkina, J. Romero, D.A. Garnovskii, J.
Garc´ıa-Va´zquez, A. Sousa, A.D. Garnovskii, Russ. J. Inorg.
Chem. 40 (1995) 1427.
[19] A.S. Burlov, A.S. Antsyshkina, J. Romero, D.A. Garnovskii, J.
Garc´ıa-Va´zquez, A. Sousa, A. Sousa-Pedrares, C. Go´mez, M.L.
Dura´n, A.D. Garnovskii, Polyhedron 18 (1999) 863.
[20] F.S. Stephens, R.S. Vagg, Inorg. Chim. Acta 57 (1982) 9.
[21] M. di Vaira, P.L. Orioli, Inorg. Chem. 6 (1967) 490.
[22] K.R. Butler, M.R. Snow, J. Chem. Soc. A (1971) 565.
[23] J. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, A. Castin˜eiras, A.
Sousa, Transition Met. Chem. 19 (1994) 343.
The 1H NMR of [CdL1(phen)] complex shows, in
addition to the signals of the Schiff base, resonances
due to the 1,10-phenanthroline hydrogen atoms around
8.7, 8.2, 7.8 and 7.2 ppm, slightly shifted in comparison
with the same signals in the free ligand. This can be
taken as a demonstration of coordination of the
phenanthroline to the cadmium atom.
4. Supplementary material
[24] J. Castro, J. Romero, J.A. Garc´ıa-Va´zquez, A. Castin˜eiras, A.
Sousa, Z. Anorg. Allg. Chem. 619 (1993) 601.
[25] J.N. Brown, R.L. Towns, L.M. Trefonas, J. Am. Chem. Soc. 92
(1970) 7436.
[26] G. Bertier, J. Serre, in: S. Patai (Ed.), The Chemistry of the
Carbonyl Group, Interscience, New York, 1966.
Atomic positions, full list of bond distances and
angles and other crystallographic data have been de-
posited as supplementary material.
[27] A.W. Addison, T.N. Rao, J. Reedijk, J. van Rijn, G.C. Ver-
schoor, J. Chem. Soc., Dalton Trans. (1984) 1349.
[28] P.C. Chieh, G.J. Palenik, Inorg. Chem. 11 (1972) 816.
[29] E. Labisbal, J.A. Garc´ıa-Va´zquez, J. Romero, S. Picos, A.
Sousa, A. Castin˜eiras, C. Maichle-Mo¨ssmer, Polyhedron 14
(1995) 663.
Acknowledgements
We thank the Ministerio de Educacio´n y Ciencia
(PB95-0827), Spain for financial support.
.

M. Bernal et al. / Inorganica Chimica Acta 295 (1999) 39–47
47
[30] F. Clifford, E. Counihan, W. Fitzgerald, K. Seff, C. Simmons, S.
[33] R.G. Inskeep, J. Inorg. Nucl. Chem. 24 (1962) 763.
[34] A.A. Schilt, R.C. Taylor, J. Inorg. Nucl. Chem.
211.
[35] A.B.P. Lever, Inorganic Electronic Spectroscopy, 2nd ed., El-
sevier, Amsterdan, 1984.
Tyagi, B. Hathaway, J. Chem. Soc., Chem. Commun. (1982) 196.
[31] O.P. Anderson, J. Chem. Soc., Dalton Trans. (1973) 1237.
[32] H. Cheng, P. Cheng, C. Lee, S. Peng, Inorg. Chim. Acta 181
(1991) 145.
9
(1959)
.