Synthesis, spectroscopy, cyclic voltammetry, and magnetic studies on nickel(II) complexes with N2S3 and N2S 2 donor macrocyclic ligands

Article abstract of DOI:10.1081/SIM-200035657

Nickel(II) complexes of the general composition Ni(L)X₂ (where X = Cl, SCN and 1/2SO₄) L = 2,3-dipenyl-1,4-diaza-7,10-dithia-5,6:11, 12-dibenzo[e,k]cyclododeca-1,3-diene[N₂S₂]ane, (L ¹) and L = 1,10-d

Full text of DOI:10.1081/SIM-200035657

Synthesis and Reactivity in Inorganic, Metal-Organic and Nano-Metal Chemistry, 35:101–106, 2005
Copyright # 2005 Taylor & Francis, Inc.
ISSN: 0094-5714 print/1532-2440 online
DOI: 10.1081/SIM-200035657
Synthesis, Spectroscopy, Cyclic Voltammetry, and Magnetic
Studies on Nickel(II) Complexes with N2S3 and N2S2 Donor
Macrocyclic Ligands
Sulekh Chandra and Rajiv Kumar
Department of Chemistry, Zakir Husain College (University of Delhi), New Delhi, India
et al., 2001, Vries and Reedijk, 1991). A new variety of
Nickel(II) complexes of the general composition Ni(L)X2 (where nickel(II) complexes with N2S2 (L1) and N2S3 (L2) donor
X 5 Cl, SCN and 1SO4) L 5 2,3-dipenyl-1,4-diaza-7,10-dithia-
macrocyclic ligands have been prepared and characterized in
this article. The electrochemical properties have been studied
extensively for nickel(II)/nickel(I) couples.
5,6 : 11,12-dibenzo[e,2k]cyclododeca-1,3-diene[N2S2]ane, (L1) and
L 5 1,10-diaza-4,7,13-trithia-2,3 : 8,9-dibenzo-[b,h]-cyclo- penta-
deca-11,15-dione[N2S3]ane (L2) have been synthesized and charac-
terized by elemental analyses, magnetic moments, IR and
electronic spectral studies. The nickel(II) complexes show
magnetic moments corresponding to two unpaired electrons
except [Ni(L1)](NO3)2, which is diamagnetic. Various ligand field
parameters have been calculated and discussed. The electrochemi-
cal properties for Ni(II)/Ni(I) couples have been studied
extensively.
EXPERIMENTAL
All chemicals used in the present investigation were of AR
grade and were purchased from Sigma Chemical Co., U.S.A.,
E. Merck, Germany or Sarabhai Merck Company, India.
Ethanol used was of analytical grade procured from S.D.
Fine Chemicals Pvt. Ltd. It was dried by storing over clean,
dried sodium wire, refluxed for 30 min and distilled using a
double walled condenser at 78 8C.
Keywords IR, 1H NMR, Nickel(II), macrocyclic ligands, cyclic
voltammetry
Physical Measurements
The magnetic susceptibilities were measured on a Gouy
balance using Hg[Co(NCS)4] as a caliberant. Infrared spectra
of the complexes were recorded on a Perkin-Elmer-FTIR
1710 automatic recording spectrophotometer in KBr. Elec-
tronic spectra of the complexes were recorded on a DMR-21
automatic recording spectrophotometer in DMF solution. Con-
ductance measurements in nitromethane were carried out on a
Leeds Northup Model 4995 conductivity bridge. Analyses of
carbon and hydrogen were performed at the Microanalytical
Laboratory of the Central Drug Research Institute, Lucknow,
India. The nitrogen contents of the complexes were determined
INTRODUCTION
Research on diverse aspects of new macrocylic compounds
has attracted world-wide interest in recent years (Arca et al.
2001; Tarafader et al., 2001). Transition metal complexes of
mixed donor macrocyclic ligands constitute a potentially
important class of molecules for molecular electronics and
catalytic reductions (Canales et al., 2000). In a series of
recent papers, the synthetic and characterization aspects of a
number of transition metal complexes of different donor
atoms have been described (Comba et al., 2002; Valencia
1
using Kjeldahl’s method. The H NMR spectra of the macro-
cyclic ligands were recorded on Bruker Avance 300 spectro-
photometer at 100 kHz modulation at room temperature. The
voltammograms and the simultaneous current intensity-time
plots for electrolysis were registered in a x-y Houston-
Received 24 September 2003; accepted 17 May 2004.
Rajiv Kumar gratefully acknowledges his younger brother Bitto for
motivation. Thanks are also due to the Principal of Zakir Husain
College, New Delhi, for providing laboratory facilities, to the Univer-
sity Grants Commission, New Delhi for financial assistance and the Ommigraphic 2000 recorder. The values of EF for reversible
University Science Instrumentation Center, Delhi University, for
or quasi-reversible redox transformations were calculated as
recording IR spectra. Thanks are also due to the Solid State Physics
the midpoints between the anodic and cathodic peaks. The dis-
tances between peaks (DE) were used as the parameters for the
Laboratory India for recording magnetic moments.
Address correspondence to Sulekh Chandra, Department of Chem-
istry, Zakir Husain College (University of Delhi), Jawahar Lal Nehru
Marg, New Delhi 110002, India. E-mail: schandra_00@yahoo.com
characterization of the reversibility of the electrochemical
transformation.
101

102
S. CHANDRA AND R. KUMAR
Preparation of the Ligands
Nickel(II) Complexes with the Ligand L1 (2,3-Diphenyl-
1,4-diaza-7,10-dithia-5,6 : 11,12-dibenzo[e,k]cyclododoca-
1,3-diene[N2S2]ane)
All of the nickel(II) complexes have the composition
Preparation of 1,2-di(o-aminophenylthio)ethane
This diamine was prepared by heating o-HSC6H4NH2
(0.01 mole, 1.25 g) with absolute (99%) EtOH (3 mL) contain-
ing Na (0.46 g, 0.02 g atom); BrCH2CH2Br (0.372 mL,
0.02 mole) in ethanol (1 mL) was added drop-wise with
constant stirring (nitrogen atmosphere) to the refluxing
solution. The mixture was then cooled to 25 8C and poured
into water (300 mL). The solid mass so obtained was filtered
washed with H2O and dried. The product was recrystallized
from EtOH. A yellowish colored solid was obtained. Yield
[Ni(L1)X2] (where X ¼ Cl, SCN and 1SO4) and
2
[Ni(L1)](NO3)2. Condensation between the NH2 group of
diamine and the CO group of the diketone formed a new
C55N group. The infrared spectrum shows a sharp band at
1590 cm21 due to the C55N group (Mandal and Nag, 1983;
Rao and Zacharias, 1977).
The formation of the complexes may be represented by the
following equation.
1
2.19 g (70%); m.p. 75 8C. H NMR: (CDCl3) d: 6.3 (2H, d,
J ¼ 6.8), 7.1 (2H, m), 6.6 (2H, m), 5.35 (4H, s), 7.2 (2H, d,
NiX2 ꢀ nH2O þ L1ꢁꢁ!NiðL1ÞX2 þ nH2O
J ¼ 7.5), 2.8 (4H, m, S-CH2).
Ligand L1
The above complexes may be four-coordinate, five-coordi-
nate or six- coordinate depending upon the nature of the
anions involved in coordination. Magnetic moments
(Table 1) of the complexes, discussed below, suggest six-co-
ordinate octahedral geometry for the chloro and thiocyanato
complexes, four-coordinate square-planar geometry for
[Ni(L1)](NO3)2 and five-coordinate square-pyramidal
geometry for [Ni(L1)SO4].
To an ethanolic solution (25 mL) of 1,2-di(o-aminophe-
nylthio)-ethane (0.005 mol, 0.723 g) was added to an ethanolic
solution (25 mL) of benzil (0.005 mol, 1.05 g) in the presence
of 1 mL conc. HCl and the resulting solution was boiled
under reflux for 3–4 h. On cooling, light yellowish crystals sep-
arated out which were filtered, washed with ethanol and dried
under vaccum over P4O10. Yield 1.24 g (70%); m.p. 182 8C. 1H
NMR: (CDCl3) d: 7.2–7.24 (10H, m), 6.9 (2H, d, J ¼ 7.2), 7.1
(24H, m), 6.6 (2H, m), 7.27 (2H, d, J ¼ 7.4), 4.0 (4H, m,
S-CH2).
The magnetic moments of the complexes at room tempera-
ture (300 K) lie in the range 2.89–3.01 B.M (Chandra and
Singh, 1986) corresponding to two unpaired electrons, except
for [Ni(L1)](NO3)2, which is diamagnetic. The molar conduc-
tance measurements lie in the range 6–18 V21 cm2 mol21 for
all the complexes expect for [Ni(L1)](NO3)2, which shows
molar conductance of 205 V21 cm2 mol21 corresponding to a
1:2 electrolyte (Bentini and Sabatini, 1966).
Ligand L2
To an ethanalic solution (25 mL) of thiodiglycolic acid
(0.02 mole, 2.89 g), an ethanolic solution (25 mL) of 1,2-di(o-
aminophenylthio)ethane (0.02 mole, 5.53 g) in absolute
ethanol (25 mL) was added drop-wise with constant stirring
at a temperature of 65 8C. The solution was then concentrated
to half of its volume under reduced pressure and kept for two
days at room temperature. Light yellowish crystals separated
out. The resulting crystals were filtered, washed with ethanol
[Ni(L1)Cl2] and [Ni(L1)(NCS)2]
The n(C55N) bands in the infrared spectra of [Ni(L1)Cl2]
and [Ni(L1)(NCS)2] appear at 1590 and 1592 cm21, respect-
ively (Lever, 1968). This indicates that the ligand is macrocylic
in nature. No IR bands are observed for free CO or NH2 groups.
However, four new bands appeared corresponding to amide
groups in the IR spectrum of the ligand at 1680, 1620, 1520,
and 1335 cm21indicate that complete condensation has taken
place. The IR spectrum of [Ni(L1)(NCS)2] shows a n(CN)
band at 2089 cm21 corresponding to coordinated NCS. The
infrared spectrum of the [Ni(L1)Cl2] shows bands at 390–
410 cm21 corresponding to coordinated chloro groups. The
electronic spectrum of [Ni(L1)Cl2] complex displays three
bands at 10,080, 16,806 and 27,580 cm21. [Ni(L1)(NCS)2]
displays (Livingstone and Nolan, 1969) bands at 11,325,
16,994, and 28,089 cm21. These bands may be assigned
1
and dried over P4O10. Yield 5.47 g (65%); m.p. 195 8C. H
NMR: (CDCl3) d: 7.2 (4H, m), 6.8 (2H, d, J ¼ 7.1), 6.5 (2H,
d, J ¼ 6.8), 3.0 (4H, m), 2.8 (4H, s).
Preparation of the Complexes
A general method has been adopted for the preparation of
the complexes. A hot (65–70 8C) aqueous ethanol solution
(25 mL, 1:1 v/v) of the hydrated metal salt (0.01 mole) and a
hot ethanol solution (25 mL) of the respective ligand
(0.01 mole) were mixed. The mixture was refluxed for about
3–4 h at 75–80 8C. Upon cooling to 6 8C, the complexes sep-
arated out. They were filtered, washed with 98% ethanol and
dried over P4O10.
3
to the following transitions 3A2g ! T2g(F) (n1),
3
3
3
3A2g ! T1g(F) (n2), and A2g ! T1g(P) (n3), in order of
increasing energy, respectively, characteristic of an octahedral
geometry (Chandra, 1982) (Figure 2).
RESULTS AND DISCUSSION
Both ligands were synthesized by the scheme in Figure 1.

STUDIES ON NICKEL(II) COMPLEXES
103
FIG. 1. Synthesis and structure of macrocyclic ligand L1 and L2.
[Ni(L1)](NO3)2
sulfato group acts as unidentate (Bentini and Sabatini, 1966).
Thus, five-coordinate structure (square-pyramidal or
a
The infrared spectrum of the nitrato complex shows a band at
1385 cm21 corresponding to an uncoordinated nitrate group.
Further, the complex was found to be diamagnetic (no unpaired
electrons) in the solid as well as in benzene solution. This
suggests a square-planar geometry around nickel(II) (Chandra
and Singh, 1986). The electronic spectrum of this complex
displays three well-defined bands at 18,115, 22,540, and
trigonal-bipyramidal) may be suggested for this complex.
The electronic spectrum of the complex shows two absorp-
tion bands at 10,425 and 12,475 cm21, which may be assigned
3
3
to 3E ! A2 (F) (n1) and 3E ! B2 (F) (n2) transition respect-
ively, corresponding to five-coordinate square-pyramidal
geometry (Livingstone and Nolan, 1969) (Figure 4).
26,240 cm21
, which may be assigned, respectively, to
1A1g ! A2g (n1), 1A1g ! B1g (n2), and 1A1g ! Eg (n3) tran-
sitions corresponding to square-planar geometry (Figure 3). The
first two bands are purely d-d transitions, whereas n3, obviously
is enveloped by strong charge transfer (Chandra and Singh, 1986).
1
1
1
Nickel(II) Complexes with the Ligand L2 (1,10-Diaza-
4,7,13-trithia-2,3:8,9-dibenzo[b,h]-cyclopentadeca-
11,15-dione[N2S3]ane)
All the complexes have the composition [Ni(L2)X]X
(X ¼ Cl, NO3 or NCS) and [Ni(L2)SO4]. The formation of
the complexes may be represented by the following equation.
[Ni(L1)SO4]
The infrared spectrum of the complex shows bands at 940
(n1), 1050 (n2) and 1150 (n3) cm21, which indicate that the
NiX2 ꢀ nH2O þ L2ꢁꢁ!½Ni(L2X]X þ nH2O

104
S. CHANDRA AND R. KUMAR
TABLE 1
Elemental analyses and magnetic moments of nickel(II) complexes
Elemental analyses (%)
found/(calcd.)
Formula
weight
M. p. Yield
(%)
S. no.
Compound
Color
White
(8C)
Ni
—
C
N
H
meff (B.M.)
(1) L1
C28H22N2S2
(2) [Ni(L1)CI2]
450.62
580.23
625.45
633.27
605.35
390.52
520.13
565.35
573.17
545.25
180
70
74.12
6.0
4.32
—
(74.60) (6.20) (4.90)
57.40 40.6 3.63
Light
green
Purple
240
216
235
224
195
226
217
235
221
43
48
52
58
65
48
50
52
57
10.0
3.02
2.89
C28H22CI2N2NiS2
(3) [Ni(L1)(SCN)2]
C30H22N4NiS4
(10.12) (57.96) (4.83) (3.83)
9.10 57.21 8.51 2.94
(9.37) (57.61) (8.95) (3.55)
9.01 52.71 8.52 3.14
(9.27) (53.10) (8.84) (3.51)
9.35 55.41 4.45 3.55
(9.70) (55.55) (4.63) (3.67)
(4) [Ni(L1) (NO3)2]
C28H22N4NiO6S2
Dark
green
Green
Diamagnetic
2.96
(5) [Ni(L1)SO4]
C28H22N2NiO4S3
(6) L2
White
—
55.30
(55.36) (7.17) (4.66)
41.20 5.20 3.11
7.10
4.50
—
C18H18N2O2S3
(7) [Ni(L2)CI]CI
C18H18Cl2N2NiO2S3
(8) [Ni(L2)(NCS)](NCS)
C20H18N4NiO2S5
(9) [Ni(L2)(NO3)](NO3)
C18H18N4NiO8S3
(10) [Ni(L2)SO4]
C18H18N2NiO6S4
Blackish
green
Green
11.00
3.00
(11.29) (41.57) (3.47) (3.47)
10.10 42.24 9.80 3.00
(10.39) (42.49) (9.90) (3.22)
10.00 37.00 9.71 2.91
(10.25) (37.71) (9.77) (3.18)
10.65 39.00 4.90 3.15
(10.77) (39.65) (5.14) (3.30)
2.91
Light
green
Black
green
2.95
2.98
The magnetic moments of the complexes lie in the range indicating that complete condensation has occurred. A single,
2.90–3.01 B.M. corresponding to two unpaired electrons. The sharp band observed in the region 3340–3380 cm21 may be
molar conductivity of Ni(L2)X2 (X ¼ Cl, NO3 or NCS) in assigned to n(N-H) of a secondary amino group (Nakamoto,
nitrobenzene was found in the range 80–95 V21 cm21 mol21
,
1978).
which indicates that the complexes are 1:1 electrolytes and
The IR spectrum of the thiocyanate complex shows two
n(CN) absorptions at 2085 and 2052 cm21 indicating two
may be formulated as [Ni(L2)X]X (X ¼ Cl, NO3 NCS).
The IR spectrum of the ligand (L2) shows moderate-inten- types of thiocyanato linkages, one corresponding to coordi-
sity absorptions in the range 1600–1630 cm21 attributable to nated and the other to uncordinated NCS (Bentini and
the imine n(C55N) (Mandal and Nag, 1983; Rao and Zacharias, Sabatini, 1966; Lever, 1968; Chandra et al., 2003).
1977) but no bands are observed for free COOH or NH2 groups
and four new bands corresponding to amide groups (Rosokha
et al., 1993) at 1680, 1620, 1520, and 1325 cm21 appeared,
FIG. 2. Suggested structure of [Ni(L1)X2 where X ¼ Cl and NCS.
FIG. 3. Suggested structure of [Ni(L1] (NO3)2.

STUDIES ON NICKEL(II) COMPLEXES
105
FIG. 5. Suggested structure of [Ni(L1)X]X, where X ¼ Cl, SCN, NO3 and
FIG. 4. Suggested structure of [Ni(L1)SO4], X ¼ OSO3.
12SO4.
The IR spectrum of nitrate complex exhibits bands at 1425
(n1), 1375 (n3), 1201 (n5), 1010 (n2), m and 836 (n6) cm21. The
difference between n1 and n5 is ꢀ125 cm21, which indicates
that the nitrate groups act as unidentates in this complex. A
broad band at 1385 cm21 corresponding to uncoordinate
nitrate group is also present in the IR spectrum of the
complex (Chandra, 1982).
3
3
given in Table 2. The transition energies B2g and Eg of the
3T2g levels are used for calculating the ligand field parameters
(Lever, 1968) Ds and Dt. These are the tetragonal splitting par-
ameters, which are related to the transition energy. Dqxy and
Dqz are the splitting parameters for in-plane and for axial
ligands. These parameters were calculated by means of the fol-
lowing equations.
The sulfate complex shows IR spectral bands at 935 (n1),
1040 (n2), and 1145 (n3) cm21 indicating that the sulfate
group acts as a unidentate (Chandra and Gupta, 2002).
The electronic spectra of the nickel(II) complexes exhibit
three strong bands at 9,945–10,666 (n1), 12,455–15,321 (n2),
and 25,461–30,426 (n3) cm21, well within the range for the
six-coordinate octahedral geometry for the complexes as
reported earlier (Lever, 1968). The first two bands result
from the splitting of one band, and can be assigned to
3
3
Dt ¼ 4=35ð B2g ꢁ EgÞ
Dqz ¼ 1=10ð2nEg ꢁ B2gÞ
2
Dqxy ¼ 1=10ðnB2gÞ
Dn ¼ 6Ds ꢁ ð5=4ÞDt
McClure’s (McClure, 1961) parameters dt2g and deg depend
upon the splitting of the t2g and eg orbitals. ds and dp were
determined from the crystal field parameters Ds and Dt by
the equations shown below.
1
3
3B1g ! 3Eg (n1) and B1g ! B2g (n2) transitions, assuming
3
the effective symmetry to be D4h (originating from T2g in
Oh symmetry). The other two higher frequency bands can be
3
3
3
2
assigned to B1g ! A2g(F) and B1g ! A2g(P) on the basis
dt2g ¼ 3Ds ꢁ 5Dt
deg ¼ 4Ds þ 5Dt
of symmetry arguments (Figure 5).
ds ¼ ꢁð1=8Þð15Dt þ 12DsÞ
dp ¼ ð1=2Þð5Dt ꢁ 3DsÞ
The value of the Ds parameter is found be greater than Dt
Ligand Field Parameters
Lever (Lever, 1968) have devised normalized spherical
harmonic Hamiltonian parameters applicable to molecules of
D4h symmetry. The values of ligand field parameters are for all complexes. The ratio of these parameters, Dt/Ds,
TABLE 2
Ligand field parameters and NSH parameters for nickel(II) complexes
S. no
Compound
Dt
Dqz
Dxqy
Ds
dt2g
d
d
(2)
(3)
(5)
(7)
(8)
(9)
(10)
[Ni(L1)CI2]
532
490
350
290
310
470
286
601
640
620
710
690
650
743
1245
1490
1310
1295
1390
1450
1532
529
690
710
560
770
650
832
1013
380
380
230
860
400
1066
210
106
408
785
108
930
711
536
655
190
115
380
575
—
[Ni(L1)(NCS)2]
[Ni(L1)SO4]
[Ni(L2)CI]CI
[Ni(L2)(NCS)](NCS)
[Ni(L2)(NO3)](NO3)
[Ni(L2)SO4]

106
S. CHANDRA AND R. KUMAR
provides information about r2/R2, where r is a average radius
of the d-shell and R the average metal ligands distance.
s-bonding along the xy-plane is strong. It is related to the
negative sign of the s parameters values. But the dp values
are positive in our result. It indicates that the p bonding
effect is relatively more important along the axial direction
than s-bonding.
thiosemicarbazone. Synth. React. Inorg. Met.-Org. Chem. 2003,
33, 147–164.
Comba, P.; Lambeka, Y. D.; Nazarenko, A. Y.; Prikhod’ko, A. I.;
Pritzkow, H.; Taraszewska, J. Cooperative effects in the binding
of substrates to nickel(II) and nickel(III) complexes with a bis
(macrocycle) ligand. Eur. J. Inorg. Chem. 2002, 1871–1882.
Gobi, K. V.; Uhsaka, T. Electrochemical and spectral properties of
novel dinickel(II) and dicopper(II) complex with N,N-linked bis(-
pentaaza-cyclotetradecane). Inorg. chim. Acta 1998, 44, 269–278.
Jing-Li, X.; Xiao-Ming, R.; Cheng, H.; Song, Y.; Chun-Yin, D.;
Song, G.; Qing, G.; Qing-Jin, M. New ion-pair nickel(III) com-
plexes containing [Ni(‘S2’)2] (‘S2’22 ¼ 1,2-benzenedithiolate)
fragments: synthesis, crystal structure and properties. Polyhedron
2003, 22, 299–305.
Cyclic Voltametry
The electrochemical behavior of the nickel(II) complexes
was studied in acetonitrile. A quasi-reversible redox process,
assigned to the Ni(III)/Ni(II) couple was observed. EF (Gobi
and Uhsaka, 1998) (binding constant) ¼ 1.085
V
An irreversible process where
Lever, A. B.P. Inorganic Electronic Spectroscopy; Elsevier: Amster-
dam, New York, 1968.
(DE ¼ 86 mV).
Ecat ¼ 21.45 V is attributed to the Ni(II)/Ni(I) couple. A
small additional peak at ca. 0.59 V is assigned to adsorption
effects. A peak, which may be assigned to the ligand oxidation,
was observed at 1.25 V (Jing-Li et al., 2003).
Livingstone, S. E.; Nolan, J. D. Sulphur-nitrogen chelating agents.
VII. Five- and six-coordinate complexes of cobalt(II), nickel(II),
and copper(II) with an S-N-S-tridentate ligand. Aust. J. Chem.
1969, 22, 1817.
Mandal, S. K.; Nag, K. Dinuclear metal complex. Part 2. Synthesis,
characterization, and electrochemical studies of macrocyclic
dicopper(II) complexes. J. Chem. Soc. Dalton Trans. 1983,
2429–2434.
The EF values for the single quasi-reversible redox trans-
formation of the nickel(II) complexes are strongly anion
dependent and decrease in the order SCN . NO3 . Cl . SO4.
McClure, D. S. Advances in Chemistry of Coordination Compounds;
Krisehner, S., Ed.; Mc-Millan: New York, 1961; p. 490.
REFERENCES
Arca, M.; Blake, A. J.; Casabo, J.; Demartin, F.; Devillanova, F. A.; Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coordi-
Garau, A.; Isaia, F.; Lippalis, V.; Kivekas, R.; Muns, V.; nation Compounds, 3rd Ed.; Wiley Interscience: New York, 1978.
Schroder, M.; Verani, G. Confromationally locked pentadentate Rao, C. R.K.; Zacharias, P. S. Studies on dinuclear metal complexes of
macrocycle containing the 1,10-phenanthroline unit. Synthesis macrocyclic ligands with varying chelate ring size. Polyhedron
and crystal structure of 6-oxa-2,8-dithia- [9](2,9)-1,10-phenanthro- 1977, 16 (7), 1201–1209.
linophane (L) and its coordination properties to Ni(II), Pd(II), Rosokha, S. V.; Lampeka, Y. D.; Matoshtan, I. M. Synthesis and prop-
Pt(II), Ph(II), and Ru(II). J. Chem. Soc. Dalton Trans. 2001,
1180–1188.
Bentini, I.; Sabatini, A. Infrared spectra of subustituted thiocyanato
erties of a new series of bis(macrocyclic) dicopper(II,II), dinickel
(II,II) and dinickel(III,III) complexes based on the 14-membered
pentaaza Unit. J. Chem. Soc. Dalton Trans. 1993, 631.
complexes, the effect of the substitutents on bond type II. Inorg. Shakir, M.; Varkey, S. P.; Hameed, P. S. Divalent Co, Ni, Cu, and Zn
Chem. 1966, 5, 1025. complexes of tetraazamacrocycles bearing polyamide groups: syn-
Canales, J.; Ramirez, J.; Estiu, G.; Costamagna, J. Bis-bipyridine thesis and characterization. Polyhedron 1993, 12, 2775.
hexa-aza-macrocyclic complexes of zinc(II) and nickel(II) and Tarafader, M. T.H.; Saravanan, N.; Crouse, K. A. Coordination and
the catalytic reduction of carbon dioxide. Polyhedron 2000, 19,
2373–2381.
Chandra, S. Synthesis and characterization of Co(II) complexes of
biological activity of nickel(II) and copper(II) complexes with
nitrogen-sulphur donor ligands derived from S-benzyldithiocarba-
zate (SBDTC). Transition Met. Chem. 2001, 26, 613.
cyclohexanone semicarbazone and cyclohexanone thiosemicarba- Valencia, L.; Adams, H.; Bastida, R.; Fenton, P. E.; Maeias, A.;
zone. Synth. React. Inorg. Met.-Org. Chem. 1982, 12, 923.
Chandra, S.; Gupta, K. Twelve-, fourteen- and sixteen-membered
macrocyclic ligands and a study of the effect of ring size on
ligand field strength. Transition Met. Chem. 2002, 27, 329–332.
Chandra, S.; Singh, R. Reactions of the coordinated mercaptide group.
Mahia, J.; Spey, S. E. The synthesis of three novel pendant
armed macrocycle ligands. The X-ray crystal structure of
cadmium complex derived from the first oxaaza macrochelate
bearing two alkyloted aromatic amine functions. Polyhedron
2001, 20, 3091–3091.
IV. Reactions of alkyl iodides on bis(thiosemicarbazonato) Vreis, N.; Reedijk, J. Nickel template synthesis of pentadentate
chelates of nickel(II). Synth. React. Inorg. Met.-Org. Chem.
1986, 16 (7), 1025–1033.
macrocycle nitrogen-sulfur ligands. Single-crystal X-ray structure
of (1,10-diaza-4,7,13,16-tetrathia-5,6:14,15-dibenzocylooctadeca-
ne)nickel(II) bis(tetra-phenylbora-te)-acetonitrile (1/3). Inorg.
Chem. 1991, 30, 3700–3703.
Chandra, S.; Tyagi, V. P.; Raizada, S. Synthesis, EPR, electronic and
magnetic, studies on cobalt(II) complexes of semicarbazone and