Syntheses, characterization and antifungal activity of heteroleptic nickel(II) complexes with N-alkylsulfonyldithiocarbimates and phosphines

Article abstract of DOI:10.1016/j.molstruc.2016.02.060

Four nickel(II) complexes of general formula [Ni(RSO₂N=CS₂) (PPh₃)₂] where R = CH₃ (2a), CH₃CH₂ (2b), CH₃(CH₂)₃ (2c) and CH₃(CH_2<

Full text of DOI:10.1016/j.molstruc.2016.02.060

Journal of Molecular Structure 1114 (2016) 21e29
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: http://www.elsevier.com/locate/molstruc
Syntheses, characterization and antifungal activity of heteroleptic
nickel(II) complexes with N-alkylsulfonyldithiocarbimates and
phosphines
,
Antonio E.C. Vidigal a, Mayura M.M. Rubinger a *, Marcelo R.L. Oliveira a, Silvana Guilardi b,
b
c
d
ꢀ
Rafael A.C. Souza , Javier Ellena , Laercio Zambolim
a Departamento de Química, Universidade Federal de Viçosa, Viçosa, MG, CEP 36570-000, Brazil
Instituto de Química, Universidade Federal de Uberlandia, Uberlandia, MG, CEP 39400-902, Brazil
b
^
^
c
~
~
~
Instituto de Física de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP, CEP 13566-590, Brazil
d Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, MG, CEP 36570-000, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
Four nickel(II) complexes of general formula [Ni(RSO2N]CS2) (PPh3)2] where R ¼ CH3 (2a), CH3CH2 (2b),
CH3(CH2)3 (2c) and CH3(CH2)7 (2d) and PPh3 ¼ triphenylphosphine; and two nickel(II) complexes of
general formula [Ni(RSO2N]CS2)dppe] where R ¼ CH3(CH2)3 (3c) and CH3(CH2)7 (3d) and dppe ¼ 1,2-
bis(diphenylphosphine)ethane) were prepared. These new complexes were obtained by the reaction of
nickel(II) chloride hexahydrate with potassium N-alkylsulfonyldithiocarbimates and the appropriate
phosphine using ethanol/water as solvent. The IR, UVeVis and 1H, 13C and 31P NMR spectra, elemental
analysis of Ni and the HR-ESI-MS were consistent with the formation of square planar nickel(II) com-
plexes with mixed ligands. The structures of the compounds 2b and 2c were determined by single crystal
X-ray diffraction. The compounds are isostructural and crystallize in the space group P1 of the triclinic
system. The activities of the complexes were investigated in vitro against Botrytis cinerea, Colletotrichum
acutatum and Alternaria solani, fungi species that affect various commercially important plants. All the
complexes were active.
Received 22 December 2015
Received in revised form
15 February 2016
Accepted 15 February 2016
Available online 17 February 2016
Keywords:
Dithiocarbimates
Phosphynes
Nickel(II) complexes
Antifungal activity
Crystal structure
© 2016 Elsevier B.V. All rights reserved.
1. Introduction
and also that Zn(II) and Ni(II) complexes with these ligands are
good accelerators for the vulcanization of natural rubber [7,8].
Dithiocarbamates and their complexes are widely used in agri-
culture. They are multisite contact fungicides that work by pro-
tecting the plant surface to prevent infection [1]. Interestingly,
these compounds are also used as accelerators of the rubber
vulcanization process [2]. Although presenting related structures
(Scheme 1), dithiocarbimates are much less common in the liter-
ature and have no industrial or commercial applications yet. Aim-
ing to deepen the knowledge on the dithiocarbimates chemistry
and applications, we have been investigating the synthesis of
dithiocarbimate-metal complexes and their antifungal and vulca-
nization activities. We have discovered that homoleptic Zn(II), Ni(II)
and Sn(IV) complexes with N-R-sulfonyldithiocarbimates are active
against Colletotrichum gloeosporioides and Botrytis cinerea [3e6],
Some heteroleptic nickel, palladium and platinum complexes with
aromatic sulfonyldithiocarbimates and phosphines have also been
prepared [9e12], but no biological studies with these compounds
were reported so far.
Here we describe the syntheses and characterization of six new
heteroleptic
nickel(II)
complexes
with
alkyl-
sulphonyldithiocarbimates and phosphine ligands, and their anti-
fungal activities against B. cinerea, Colletotrichum acutatum and
Alternaria solani.
B. cinerea is responsible for the gray mold disease on more than
200 host plants [13]. C. acutatum is an important anthracnose
pathogen, also infecting a wide variety of hosts, including vegeta-
bles, field and forage crops, fruit trees and ornamentals [14]. The
early blight disease caused by A. solani has a great destructive po-
wer on tomato and potato cultures [15]. Alternaria and Colleto-
trichum species are also related to human infections, especially in
immunocompromised patients [16].
* Corresponding author.
E-mail address: mayura@ufv.br (M.M.M. Rubinger).
http://dx.doi.org/10.1016/j.molstruc.2016.02.060
0022-2860/© 2016 Elsevier B.V. All rights reserved.

22
A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
[11211], 429 [304] and 548 [104]. IR (most important bands)
(cmꢁ1): 1457
(C]N), 1305 nas(SO2), 1133 nsym(SO2), 924 nas(CS2)
and 375
(NiS). 1H NMR ( ): 7.54e7.15 (m, 30H, H20eH60), 2.94 (s,
3H, H2). 13C NMR (
S-
S-
S
R1
R2
n
n
d
N C
R1 N C
d
), J (Hz): 197.2 (C1), 41.8 (C2), triphenylphos-
S-
phine signals: 134.3 (t, JCP ¼ 5.3, C20 and C60), 130.7 (s, C40), 129.2 (d,
JCP ¼ 45.9, C10), 128.3 (t, JCP ¼ 4.5, C30 and C50). 31P NMR (
d): 34.36
(a)
(b)
(s).
Scheme 1. General formulas of (a) dithiocarbamate and (b) dithiocarbimate anions.
[Ni(CH3CH2SO2N]CS2)(PPh3)2] (2b): Anal. Calc.: Ni, 7.66. Found:
7.51%. HR-ESI-MS [M þ H]þ m/z Calc.: 766.0729. Found: 766.0756.
M.p. with decomposition (ꢀC): 162.6e163.5. UVeVis
l (nm), [εo
(L molꢁ1 cmꢁ1)]: 199 [63245], 230 [23091], 261 [14184], 317
[10223], 427 [483] and 553 [132]. IR (most important bands)
2. Experimental
(cmꢁ1): 1463
and 372
n(C]N), 1304 nas(SO2), 1134 nsym(SO2), 926 nas(CS2)
2.1. Materials and methods
n
(NiS). 1H NMR ( ), J (Hz): 7.52e7.17 (m, 30H, H20eH60),
d
3.03 (q, 2H, J ¼ 7.2, H2), 1.32 (t, 3H, J ¼ 7.4, H3). 13C NMR (
d), J (Hz):
The nickel(II) chloride hexahydrate, triphenylphosphine, carbon
disulfide, potassium hydroxide and the solvents were purchased
from Vetec and used without further purification. Meth-
anesulfonamide, ethanesulfonyl chloride, butanesulfonyl chloride,
octanesulfonyl chloride and 1,2-bis(diphenylphosphine)ethane
were purchased from Aldrich. Alkylsulfonamides (except meth-
anesulfonamide) were prepared from the alkylsulfonyl chlorides by
their reaction with concentrated ammonia aqueous solution under
reflux. The sulfonamides were isolated after extraction with ethyl
acetate and solvent evaporation. The N-R-sulfonyldithiocarbimate
potassium salts dihydrate were prepared in dimethylformamide
from the sulfonamides in reaction with carbon disulfide and po-
tassium hydroxide [8,17,18]. High resolution mass spectra were
obtained with a Shimatzu LCMS-IT-TOF mass spectrometer from
acetonitrile solutions of the compounds. The UVeVis spectra were
recorded with an Agilent 8453 UVevisible spectroscopy system;
the solutions of the compounds were prepared in acetonitrile. The
IR spectra were recorded with a Perkin Elmer FT-IR 1000 infrared
spectrophotometer using CsI pellets. The NMR spectra were ob-
tained at 300 K using a VARIAN 300 MHz spectrometer, from so-
lutions in CDCl3 with TMS as internal standard for the 1H (300 MHz)
and 13C (75 MHz) spectra, or with H3PO4 as external standard for
the 31P (121 MHz) spectra. Melting points were determined with a
MQAPF-302 equipment and are reported without correction. Nickel
was analyzed by atomic absorption with a VARIAN AA-200 Spec-
trometer. For the biological tests, B. cinerea and C. acutatum were
isolated from infected strawberry tissues and incubated for 4 day at
20 ꢀC and 7 day at 25 ꢀC, respectively. A. solani was isolated from
infected potato and incubated for 7 day at 25 ꢀC. The culture me-
196.6 (C1), 48.5 (C2), 8.1 (C3), triphenylphosphine signals: 134.3 (t,
JCP ¼ 5.3, C20 and C60), 130.7 (s, C40), 129.3 (d, JCP ¼ 45.9, C10), 128.3
(t, JCP ¼ 4.5, C30 and C50). 31P NMR (
d): 34.36 (s).
[Ni(CH3(CH2)3SO2N]CS2)(PPh3)2] (2c): Anal. Calc.: Ni, 7.39.
Found: 7.45%. HR-ESI-MS [M þ H]þ m/z Calc.: 794.1041. Found:
794.1115. M.p. with decomposition (ꢀC): 159.4e160.8. UVeVis
l
(nm), [εo (L molꢁ1 cmꢁ1)]: 198 [65425]; 229 [23340]; 259 [14579];
317 [10490]; 421 [535] and 557 [154]. IR (most important bands)
(cmꢁ1): 1465
n
(C]N); 1300 nas(SO2); 1131 nsym(SO2); 925 nas(CS2)
and 373
n
(NiS). 1H NMR ( ), J (Hz): 7.51e7.11 (m, 30H, H20eH60),
d
3.01 (t, 2H, J ¼ 9, H2), 1.84e1.71 (m, 2H, H3); 1.41e1.29 (m, 2H, H3),
0.86 (t, 3H, J ¼ 6, H4). 13C NMR (
d), J (Hz): 196.6 (C1), 53.9 (C2), 25.2
(C3), 21.7 (C4), 13.6 (s, C5), triphenylphosphine signals: 137.3 (t,
JCP ¼ 6.0, C20 and C60), 130.7 (s, C40), 129.2 (d, JCP ¼ 45.7, C10), 128.31
(t, JCP ¼ 5.3, C30 and C50). 31P NMR (
d): 34.40 (s).
[Ni(CH3(CH2)7SO2N]CS2)(PPh3)2] (2d): Anal. Calc.: Ni, 6.90.
Found: 6.77%. HR-ESI-MS [M þ H]þ m/z Calc.: 850.1665. Found:
850.1675. M.p. with decomposition (ꢀC): 148.8e150.1. UVeVis
l
(nm), [εo (L molꢁ1 cmꢁ1)]: 197 [68614], 228 [23983], 259 [14657],
317 [10647], 419 [714] and 555 [325]. IR (most important bands)
(cmꢁ1): 1460
n
(C]N), 1309 nas(SO2), 1134 nsym(SO2), 926 nas(CS2)
and 378
n
(NiS). 1H NMR ( ), J (Hz): 7.52e7.14 (m, 30H, H20eH60),
d
3.00 (t, 2H, J ¼ 9, H2), 1.85e1.74 (m, 2H, H3), 1.41e1.14 (m, 10H,
H4eH8), 0.86 (t, 3H, J ¼ 6, H9). 13C NMR (
d), J (Hz): 196.5 (C1), 54.2
(C2), 31.8 (C3), 29.1 (C4), 29.0 (C5), 28.5 (C6), 23.2 (C7), 22.6 (C8),
14.1 (C9), triphenylphosphine signals: 134.3 (t, JCP ¼ 5.3, C20 and
C60), 130.7 (s, C40), 129.2 (d, JCP ¼ 45.7, C10), 128.2 (t, JCP ¼ 5.3, C30and
C50). 31P NMR (
d): 34.44(s).
dium PDA (Potato Dextrose Agar) was purchased from Fluka and
[Ni(CH3(CH2)3SO2N]CS2)dppe] (3c): Anal. Calc.: Ni, 8.78. Found:
ꢀ
8.52%. HR-ESI-MS [M þ H]þm/z Calc.: 668.0573. Found: 668.0642.
was previously sterilized in autoclave for 20 min at 120 C.
M.p. with decomposition (ꢀC): 204.4e206.4. UVeVis
l (nm), [εo
2.2. Syntheses
(L molꢁ1 cmꢁ1)]: 199 [66890], 260 [27664], 308 [25732], 423 [314]
and 480 [139]. IR (most important bands) (cmꢁ1): 1479
(C]N),
1290 nas(SO2), 1123 nsym(SO2), 920 nas(CS2) and 375
(NiS). 1H NMR
n
The syntheses were performed according to Scheme 2.
n
A solution of the appropriate potassium N-R-sulfonyldithio-
carbimate dihydrate (1.0 mmol) in water (10 mL) was added to a
suspension of the phosphine (1.0 mmol of dppe or 2.0 mmol of
triphenylphosphine) in ethanol (30 mL). A solution of nickel(II)
chloride hexahydrate (1.0 mmol) in water was added to the sus-
pension and the reaction mixture was stirred for 14 h at room
temperature. The color of the suspension changed from green to
red/orange. The solid products were filtered, washed with distilled
water, ethanol and diethyl ether, and dried under reduced pressure
for one day. The yields were ca. 85%. The data for compounds 3a and
3b were in accord with the literature [10]. The data obtained for the
new compounds 2a-d and 3c-d are as follows.
(d
), J (Hz): 7.74 (s, 8H, H20 and H60), 7.56e7.43 (m, 12H, H30, H40 and
H50), 3.08 (t, 2H, J ¼ 9, H2), 2.36 (d, 4H, JHP ¼ 17, H100 and H200),
1.92e1.77 (m, 2H, H3), 1.45e1.30 (m, 2H, H3), 0.88 (t, 3H, J ¼ 6, H4).
13C NMR (
d), J (Hz): 198.1 (C1), 54.1 (C2), 25.4 (C3), 21.7 (C4), 13.6
(C5), dppe signals: 132.9 (t, JCP ¼ 5.3, C20 and C60), 131.8 (s, C40),
129.3 (t, JCP ¼ 5.2, C30 and C50), 128.3 (t, JCP ¼ 22.3, C10), 25.9 (t,
JCP ¼ 23.3, C100 and C200). 31P NMR (
d): 58.49 (s).
[Ni(CH3(CH2)7SO2N]CS2)dppe] (3d): Anal. Calc.: Ni, 8.10. Found:
8.47%. HR-ESI-MS [M þ H]þ m/z Calc.: 724.1197. Found: 724.1251.
M.p. with decomposition (ꢀC): 160.6e161.9. UVeVis
l (nm), [εo
(L molꢁ1 cmꢁ1)]: 199 [70229], 260 [29566], 309 [27276], 423 [605]
and 488 [379]. IR (most important bands) (cmꢁ1): 1468
(C]N),
1285 nas(SO2), 1126 nsym(SO2), 913 nas(CS2) and 366
(NiS). 1H NMR
n
[Ni(CH3SO2N]CS2)(PPh3)2] (2a): Anal. Calc.: Ni, 7.80. Found:
n
7.58%. HR-ESI-MS [M þ H]þ m/z Calc.: 752.0573. Found: 752.0636.
(d
), J (Hz): 7.79e7.67 (m, 8H, H20 and H60), 7.56e7.38 (m, 12H, H30,
M.p. with decomposition (ꢀC): 167.6e168.7. UVeVis
l
(nm), [εo
H40 and H50), 3.07 (t, 2H, J ¼ 9, H2), 2.36 (d, 4H, JHP ¼ 17, H100 and
(L molꢁ1 cmꢁ1)]: 198 [65206], 235 [24440], 256 [15511], 318
H200), 1.93e1.78 (m, 2H, H3), 1.38e1.19 (m, 10H, H4eH8), 0.85 (t, 3H,

A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
23
1
2PPh3
[Ni(RSO2N=CS2)(PPh3)2]
2a, 2b, 2c, 2d
NiCl2 . 6H2O, EtOH/H2O
- 8H2O, - 2 KCl
RSO2N=CS2K2 . 2H2O
1a, 1b, 1c, 1d
1
[Ni(RSO2N=CS2)(dppe)]
dppe
3a, 3b, 3c, 3d
2
5
4
3
2
3
2
9
8
7
6
5
4
3
2
R = CH3 (a), CH3CH2 (b), CH3CH2CH2CH2 (c), CH3CH2CH2CH2CH2CH2CH2CH2 (d)
'
4
'
'
'
4
'
3
2
5
'
'
'
5
3
2
'
6
'
1
'
6
"
'
2
P
1
P
P
"
1
dppe
PPh3
Scheme 2. Syntheses and NMR numbering of the nickel(II) complexes.
J ¼ 6.7 Hz, H9). 13C NMR (
d
), J (Hz): 197.9 (C1), 54.4 (C2), 31.7 (C3),
2.4. Biological assay
29.1 (C4), 29.0 (C5), 28.5 (C6), 23.4 (C7), 22.6 (C8), 14.1 (C9), dppe
signals: 132.9 (t, JCP ¼ 5.3, C20 and C60), 131.8 (s, C40), 129.3 (t,
JCP ¼ 5.3, C30 and C50), 128.3 (t, JCP ¼ 21.8, C10), 26.0 (t, JCP ¼ 23.4, C100
The antifungal activities were evaluated using the Poisoned food
technique [3]. Discs of mycelia of the fungi (diameter of 6.25 mm)
were placed on the center of Petri dishes containing 15 mL of the
culture medium (PDA) homogeneously mixed with the tested
compounds at the concentrations of 0.1, 0.2, 0.4, 0.6, 0.8 and
1.0 mmol Lꢁ1, plus dimethyl sulfoxide (1% v/v) and Tween 80 (1% v/
v). The antibiotic chloramphenicol (0.05 mL) was added to the
culture medium for testing with C. acutatum. Each treatment con-
sisted of four repetitions and the dishes were incubated at 20 ꢀC for
3 days (B. cinerea), 25 ꢀC for 6 days (C. acutatum) and 25 ꢀC for 4 days
(A. solani). The diameter of the fungus colony was measured with a
caliper vernier every 24 h from the second day of incubation. The
effects of the parent potassium dithiocarbimate salts, triphenyl-
phosphine and dppe were also tested under the same conditions.
The control (negative check treatment, four repetitions) was pre-
pared with PDA, dimethylsulfoxide and Tween in the tests with
B. cinerea and A. solani, with the addition of chloramphenicol in the
tests with C. acutatum. The results were statistically analyzed by
nonlinear regression using the concentration versus percent inhi-
bition results. The comparisons of the activities were submitted to
analyses of variance and means, and were compared by the Tukey
test (p ꢂ 0.05).
and C200). 31P NMR (
d): 58.28 (s).
2.3. X-ray diffraction studies
Suitable red crystals for X-ray structure analyses were obtained
for compounds 2b and 2c after slow evaporation of solutions in
dichloromethane/ethanol. The single crystal data of the complexes
were collected on an EnrafeNonius Kappa-CCD diffractometer us-
ing the graphite-monochromated MoKa radiation (0.71073 Å) at
293.0(2) K. The Bruker AXS Collect software was used for data
collection and also for indexing the reflections and determining the
unit cell parameters. The collected data were processed using HKL
Denzo-Scalepack system of program [19]. Absorption corrections
(GAUSSIAN for 2b and MULTI-SCAN for 2c) were applied for the
complexes using the program SORTAV [20]. The structures were
solved by direct methods (SIR-92) and refined (SHELXL-2014)
employing full-matrix least-squares on F2 [21,22]. All H atoms were
placed geometrically. The ethyl group in 2b was disordered over
two different orientations with occupancy of 50% each. The
SQUEEZE procedure in PLATON was applied for 2b [23] in order to
remove the contribution of the disordered solvent molecules to the
intensity of the Bragg reflections. Structural diagrams were drawn
using ORTEP-3 [24] and MERCURY [25]. The program WINGX [24]
was used to prepare the materials for publication. Crystal data
and details on data collection and refinement are summarized in
Table 1.
3. Results and discussion
The syntheses were performed as shown in Scheme 2. The
complexes are stable at room temperature and show red (2a-d) and
orange (3a-d) colors. Their melting temperature ranges were quite
narrow although color changes while melting indicated some

24
A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
Table 1
Crystallographic data and details of diffraction experiments for compounds 2b and 2c.
Compound
2b
2c
Empirical formula
Formula weight (g molꢁ1
Temperature (K)
Crystal system
C39H35NO2P2S3Ni
766.51
293(2)
C41H39NO2P2S3Ni
794.56
293(2)
)
Triclinic
Triclinic
Space group
P1
P1
Unit cell dimensions
a(Å)
b(Å)
c(Å)
11.569(1)
12.453(2)
14.050(1)
85.84(1)
72.95(1)
77.35(1)
1888.1(4), 2
1.348
11.704(1)
12.260(1)
14.182(1)
86.10(1)
72.39(1)
77.17(1)
1891.3(2), 2
1.395
a
(ꢀ)
(ꢀ)
b
g
(ꢀ)
Volume (Å3), Z
Calculated density (g cmꢁ3
)
m
T
(mmꢁ1
min/Tmax
)
0.799
0.687/0.945
0.800
0.784/0.961
F(000)
796
828
Crystal size (mm)
q
Limiting indices
Reflections collected
Independent reflections
Goof
0.306 ꢃ 0.189 ꢃ 0.049
1.676 to 27.521
ꢁ15,15; ꢁ16,16; ꢁ18,18
44330
0.324 ꢃ 0.164 ꢃ 0.056
2.997 to 27.487
ꢁ15,15; ꢁ15,15; ꢁ18,18
35588
range (ꢀ)
8670 [R(int) ¼ 0.0732]
8657 [R(int) ¼ 0.0441]
1.058
1.068
Data/restraints/parameters
5681/0/442
6104/0/451
R indices [I > 2
R indices (all data)
Largest diff. peak and hole (e Aꢁ3
s
(I)]
R ¼ 0.0576, wR ¼ 0. 1495
R ¼ 0.0944, wR ¼ 0.1766
0.504 and ꢁ0.528
R ¼ 0.0458, wR ¼ 0.1152
R ¼ 0.0727, wR ¼ 0.1294
0.668 and ꢁ0.451
)
R1 ¼ S (kFoj - jFck)/SjFoj; wR2 ¼ [Sw(jF2oj - jFc2j)2/SwjFo2j2]1/2
.
degree of decomposition. They are insoluble in water, ethanol,
methanol, acetone, hexane, diethyl ether and soluble in dime-
thylsulfoxide and N,N-dimethylformamide. The complexes 2a-d are
also soluble in chloroform, dichloromethane and acetonitrile, while
3a-d present low solubility in these solvents. The proposed mo-
lecular formulas of all compounds could be confirmed from the HR-
ESI-MS and atomic absorption spectrometry results. The com-
pounds 3a and 3b are described in the literature [10] and their
spectroscopic data were in agreement with the published values.
The electronic spectra of the new complexes show a weak band
at ca. 550 nm (2a-d) and ca. 480 nm (3c and 3d) due to ded
transitions, indicating a square-planar geometry around the nickel
atom. The differences in the position of the ded bands are consis-
tent with the fact of dppe being a stronger ligand than the tri-
phenylphosphine. The remaining observed bands are due to metal-
ligand charge transfer and intraligand transitions [9,10].
the double bond character of the C]N bond.
The NMR spectra showed all the expected signals for the com-
pounds and were typical for diamagnetic species, showing narrow
and well-defined signals, thus supporting the hypothesis of a
square-planar geometry around the nickel atom. The 1H NMR
spectra showed two regions associated with the phosphines
(ranging from
mates (ranging from
d
7.80 to 7.17) and the N-alkylsulfonyldithiocarbi-
3.20 to 0.50) ligands. Their integration
d
curves were consistent with a 2:1 proportion between the triphe-
nylphosphines and the N-alkylsulfonyldithiocarbimates, or a 1:1
proportion
alkylsulfonyldithiocarbimates.
The 13C NMR spectra showed the phosphine carbon signals in
the expected range of 138 to 127. The N-alkylsulfonyldithio-
carbimates moieties were responsible for the signals around 198
due to the C]N group, and below 55 due to the alkyl groups. The
between
the
dppe
and
the
N-
d
d
d
The
n
(C]N) band (1457e1459 cmꢁ1) in the vibrational spectra
chemical shifts of the carbon signals of the N-alkylsulfonyldithio-
carbimate ligands in the spectra of the complexes do not differ
significantly from those observed for the potassium N-alkylsulfo-
nyldithiocarbimate salts, except for the positions of the carbon
signals of the C]N group. These signals are shifted to higher field if
compared with the potassium N-alkylsulfonyldithiocarbimate salts
and the homoleptic nickel complexes (PPh4)2[Ni(RSO2N]CS2)2]
values [8,17,18]. For example, while the C]N signal appears at
of the complexes is shifted to higher wave numbers relative to the
spectra of the potassium dithiocarbimates (1282e1301 cmꢁ1),
while the CS2 group vibrations (912e927 cmꢁ1) has an opposite
shift (961e970 cmꢁ1, in the spectra of the free ligands [8,17,18]).
These results are consistent with a higher character of double bond
between the carbon and nitrogen atoms, and a greater character of
single bond between the carbon and sulfur atoms in the CS2 group
upon complexation. The medium intensity NiS band was observed
d
d
d
196.6 for [Ni(CH3CH2SO2N]CS2)(PPh3)2] (2b), it is observed at
223.8 in the spectrum of K2(CH3CH2SO2N]CS2) [18], and at
212.0 for (PPh4)2[Ni(CH3CH2SO2N]CS2)] [8]. These shifts are also
in the expected range of 300e400 cmꢁ1
.
Comparing the vibrational spectra of the heteroleptic complexes
2a-d and 3a-d with those of homoleptic complexes anions of gen-
eral formula [Ni(RSO2N]CS2)2]2ꢁ, it can be seen that the presence
of the phosphines causes an increase in the wavenumbers of the
consistent with the greater double bond character of the C]N
group upon complexation and the extra shielding caused by the
drift of electrons from the CS2 group to the metal, due to the high
acceptor character of the phosphines.
The carbon signals of the triphenylphosphine ligands appear as
doublets and triplets in the spectra of the complexes 2a-d, and the
carbon signals of dppe appear as triplet and pseudo-triplet (2:1:2)
in the spectra of 3c and 3d. The unfolding of these signals occur due
to the carbon-phosphorus coupling. This is also consistent with the
p
dithiocarbimate
SO2N]CS2)(PPh3)2] (2c) the
n(C]N) bands. For example, for [Ni(CH3(CH2)3
-
n
(C]N) appears at around 1465 cmꢁ1
,
while in the spectrum of (PPh4)2[Ni(CH3(CH2)3SO2N]CS2)2] this
band is observed at 1425 cmꢁ1 [8]. This difference can be explained
by the
p acceptor character of the phosphines, causing a drift of
electrons from the dithiocarbimate anion to the metal, increasing

A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
25
Fig. 1. An ORTEP drawing of 2b with atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
square-planar geometry of the complexes, as these multiplicities
are commonly observed in the 13C NMR spectra of cis-complexes of
bis-phosphines with transition metals [26].
The 31P NMR spectra were obtained at a temperature of 300 K.
Fig. 2. An ORTEP drawing of 2c with atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

26
A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
Table 2
signals are shifted to lower field when compared to the free
phosphines, that appear at ca.
ꢁ5 for triphenylphosphine and ꢁ12
Selected geometrical parameters for compounds 2b and 2c.
d
for dppe [26,27]. These shifts are caused by the nickel atom, which
deshields considerably the phosphorus atoms. Further, a greater
electron density on the phosphorus atom of dppe due to the
neighbor electron donating methylene group may force the alle-
viation of excess electron density (from the chelating dppe) to the
metal center, in contrast with the triphenylphosphine complexes,
where the phosphorus atom is attached to electron withdrawing
phenyl groups [28].
Compound
2b
2c
Bond length (Å)
NieS(1)
NieS(2)
NieP(1)
NieP(2)
C(1)eS(1)
C(1)eS(2)
NeC(1)
2.211(1)
2.193(1)
2.231(1)
2.210(1)
1.736(4)
1.748(4)
1.285(5)
1.640(3)
2.212(1)
2.194(1)
2.232(1)
2.212(1)
1.736(2)
1.753(2)
1.281(3)
1.650(2)
NeS(3)
Angles(ꢀ)
Although the phosphorus atoms are not equivalent, no split was
observed at 300 K in the 31P NMR spectra. The nonequivalence of
the phosphorus atoms becomes evident at lower temperatures. In
the spectrum of compound 2d obtained at 248 K, two doublets are
S(2)eNieP(2)
S(1)eNieS(2)
P(1)eNieP(2)
S(1)eNieP(1)
S(1)eC(1)eS(2)
NeC(1)eS(1)
NeC(1)eS(2)
C(1)eNeS(3)
92.8(1)
78.0(1)
100.1(1)
89.7(1)
105.4(2)
132.6(3)
121.9(3)
121.5(3)
92.4(1)
77.9(1)
100.7(1)
90.3(1)
105.2(1)
133.1(2)
121.7(2)
120.3(2)
observed at
d
59.63 (J ¼ 39 Hz) and
d
58.74 (J ¼ 39 Hz). The same
behavior is observed for other complexes with phosphine ligands
where a split of the phosphorus signal becomes evident at ca. 240 K
[10].
Single crystal X-ray diffraction data confirmed that the nickel
atom is coordinated by two sulfur atoms of the dithiocarbimate
ligand and by two phosphorus atoms of the triphenylphosphines in
the complexes 2b and 2c (Figs. 1 and 2). The complexes are iso-
structural and crystallize in the triclinic space group P1 with two
molecules in the unit cell. Table 2 shows selected geometrical pa-
rameters for compounds 2b and 2c.
The cis-NiS2P2 fragment has a distorted square planar geometry
due to the small S1eNieS2 angle (ca. 78ꢀ) associated with the
bidentate chelation of the dithiocarbimate moiety and a large
PeNieP angle (ca. 100ꢀ) due to the steric effect of the triphenyl-
phosphine ligands. The C1eNeS3 fragment of the N-R-sulfonyldi-
thiocarbimate ligand and the P2NiS2 moiety are coplanar. The NieP
and NieS distances are symmetric as reported for similar com-
pounds [10,11].
Table 3
Hydrogen-bond geometry (Å, ꢀ) for compounds 2b and 2c.
…
…
DonoreH Acceptor
d(DeH)
d(H A)
d(D … A)
<(DHA)
Compound 2b
C16eH16/S1
C38eH38/Ni
Compound 2c
C(4)-H4A … O(1)
0.96
0.96
2.82
2.59
3.471(4)
3.483(6)
125.9
154.0
0.97
0.97
0.93
0.93
0.93
0.93
2.60
2.88
2.88
2.59
2.59
2.56
3.235(4)
3.481(3)
3.523(3)
3.321(4)
3.462(3)
3.229(3)
123.1
120.8
127.0
136.5
157.3
129.3
…
C(2)-H2B S(1)
…
C(7)-H7 S(1)
…
C(16)-H16 O(2)ii
…
C(21)-H21 O(1)iii
C28eH28/O1 iv
Symmetry codes: (i) -x, -y, 1-z; (ii) -x, 1-y, -z; (iii) x, y, 1 þ z; (iv) 1-x, -y, -z.
Fig. 3. Packing diagram of 2b, viewed down the a axis. Dashed lines indicate CeH … N intermolecular interactions.
The phosphorus signal was observed at around
d
34 in the spectra
In both compounds, the CeS bonds are similar and slightly
shorter than typical CeS single bonds (ca. 1.81 Å) owing to a partial
of the complexes 2a-d and at 58 in the spectra of 3c and 3d. These
d

A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
27
Fig. 4. Packing diagram of 2c, viewed down the a axis. Dashed lines indicate CeH … O intermolecular interactions.
100
90
80
70
60
50
40
30
20
10
0
100
L
J
J
J
I
I
I
90
80
70
60
50
40
30
20
10
0
I
H
H
H
F
F
E
G
D
G
F
E
D
C
C
B
A
C
C
B
A
1a 1b 1c 1d 2a 2b 2c 2d PPh3 3a 3b 3c 3d dppe
1a 1b 1c 1d 2a 2b 2c 2d PPh3 3a 3b 3c 3d dppe
Compounds
Compounds
Fig. 5. Percentage of inhibition of C. acutatum in the 6th day of incubation in the
presence of the potassium N-alkylsulfonildithiocarbimates (1a-d), PPh3, dppe, and the
complexes 2a-d and 3a-d, at 1.0 mmol Lꢁ1. Values followed by the same letter do not
differ at the 5% level of significance by the Tukey test.
Fig. 6. Percentage of inhibition of B. cinerea in the 3rd day of incubation in the pres-
ence of the potassium N-alkylsulfonildithiocarbimates (1a-d), PPh3, dppe, and the
complexes 2a-d and 3a-d, at 1.0 mmol Lꢁ1. Values followed by the same letter do not
differ at the 5% level of significance by the Tukey test.
p
-delocalization in the NCS2 group. The CeN bonds [1.285(5) in 2b
In both compounds, the bond lengths and angles in the PPh3
ligands are comparable to those found in similar structures [9,31].
The phosphorus atoms exhibit distorted tetrahedral geometry, the
CeP distances and CePeC angles ranging from 1.812(2) to 1.841(4)
Å and 100.5(1) to 110.9(2)ꢀ, respectively. The CeC bond lengths in
the six phenyl rings varies from 1.354(7) to 1.404(4) Å.
and 1.281(3) Å in 2c] have a double bond character and are slightly
shorter than the ones observed in the potassium dithiocarbimates
(approximately 1.35 Å) [29,30]. These results are consistent with
the spectroscopic data. Similar behavior is observed for nickel
complexes with other dithiocarbimate ligands [9e11].

28
A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
100
90
80
70
60
50
40
30
20
10
0
molecules per unit cell.
The antifungal activities of the complexes were evaluated
H
G, H
G, H
F, G
against the plant pathogens B. cinerea, C. acutatum and A. solani. The
poisoned food methodology was used, where the growth of the
pathogen occurs in a culture medium mixed with the compound in
test [3]. An estimate of the potential activity is obtained by
measuring the diameter of the colony compared to the negative
control (white), prepared in the absence of the test substance. In
order to allow a complete comparison, the already published
complexes 3a and 3b [10] were prepared and included in the bio-
logical assays. The corresponding potassium N-alkylsulfonildithio-
carbimates (1a-d) and the free phosphines were also included.
The inhibition of the growth of B. cinerea, C. acutatum, and
A. solani by all compounds at 1.0 mmol Lꢁ1 are shown in the
Figs. 5e7. The complexes 2a-d were more active than the free li-
gands 1a-d and PPh3. In contrast, complexes 3a-d were less active
than the potassium N-alkylsulfonildithiocarbimates 1a-d and dppe.
Further, it is important to note that due to its low solubility, part of
the dppe precipitated in the culture medium. Thus the results for
dppe might be underestimated.
The Tukey test at 5% significance was applied to confirm the
differences between the inhibition caused by the 14 compounds,
and the results are shown in Figs. 5e7. The differences in the length
of the carbon chains in the R groups did not interfere appreciably in
the activity of the complexes. However, the longer chain of the octyl
group did improve the inhibition of B. cinerea (Fig. 5) and
C. acutatum (Fig. 6), according to the Tukey test at 5% level of sig-
nificance, and the complex 2d generated the best result of the se-
ries, possibly due to a better interaction with the lipophilic cell
membrane. Further, the higher activity of the complexes 2a-d in
comparison with the complexes 3a-d indicated that the mechanism
of action might involve the intracellular release of the phosphine
ligands from the complexes. This is difficult in the case of 3a-d,
since the nickel(II) forms a chelate with the diphosphine.
F
E
E
E
D
D
C
B, C
A, B
A
1a 1b 1c 1d 2a 2b 2c 2d PPh3 3a 3b 3c 3d dppe
Compounds
Fig. 7. Percentage of inhibition of A. solani in the 4th day of incubation in the presence
of the potassium N-alkylsulfonildithiocarbimates (1a-d), PPh3, dppe, and the com-
plexes 2a-d and 3a-d, at 1.0 mmol Lꢁ1. Values followed by the same letter do not differ
at the 5% level of significance by the Tukey test.
The geometric parameters of the interactions in the crystals of
compounds 2b and 2c are listed in Table 3.
…
The crystal packing in 2b shows one CeH
S intramolecular
interaction and pairs of CeH … N hydrogen bonds linking dimmers
by an inversion center which generate R22(18) ring motifs along the
[110] direction [32]. Van der Waals attractions link the dimmers in a
three-dimensional network (Fig. 3).
There are intramolecular contacts (CeH … O and CeH … S) and
three CeH … O non classical hydrogen bonds involving O1 and O2
…
oxygen atoms in the crystal of 2c. The C16eH16 O2 intermolec-
To further investigate the activity of compounds 2a-d, the
experiment was repeated in different concentrations in order to
obtain the IC50 values (Table 4), from nonlinear regression analyses
of the doseeresponse curves. Increasing the carbon chain length
causes a slight decrease in the IC50 values, confirming that the more
lipophilic compounds are the most active ones. These experiments
confirmed that the compounds 2a-d are more active than the free
PPh3.
ular interaction between two molecules related by an inversion
center generates a R22(22) ring motif. Each of these molecules also
form a second R22(22) ring motif with a neighboring molecule
…
related by another inversion center through a C28eH28
O1
interaction. These motifs are linked by C21eH21 … O1 interactions
along the c axis, giving rise to a supramolecular network (Fig. 4).
The structures show rare CeH/M intramolecular interactions
[33e35] as a result of packing effects together with the electronic
and steric restrictions of bulky ligands and the d8 electronic
…
4. Conclusions
configuration. Interactions characterized by M
H distances be-
tween 2.3 and 2.9 Å might be important for catalytic applications
[35]. In 2b the H/Ni distance is 2.90 Å and the CeH/Ni angle is
120.4ꢀ. Similar, but rather less pronounced, the H/Ni distance in 2c
is 2.96 Å and the CeH/Ni angle is 114.5ꢀ.
The analysis of the structure 2b showed the presence of disor-
dered solvent molecules that could not be reliably modeled and it
was thus omitted from the model through the use of SQUEEZE. The
void space analysis yielded a volume of 132.7 Å3 with an electron
count of 59. This corresponds well to the presence of two ethanol
Six new nickel(II) complexes with phosphines and N-alkylsul-
fonyldithiocarbimates were prepared and characterized by high
resolution mass spectrometry, elemental analyses for Ni, UVeVis,
IR, 1H, 13C and 31P NMR. Their structures were further investigated
through X-ray diffraction experiments with compounds 2d and 2c.
The crystallographic data shows that the complexes 2b and 2c are
isostructural and the coordination about the Ni atom resulted in a
distorted square planar geometry. The spectroscopic and X-ray data
for 2b and 2c show an interesting relation with the data for the
homoleptic complexes [Ni(RSO2N]CS2)2]2ꢁ. The CeN bond lengths
in 2b and 2C are shorter than those in the homoleptic complexes
Table 4
Concentrations of 2a-d and PPh3 for 50% inhibition (IC50) of the growth of Colleto-
trichum acutatum, Botrytis cinerea and Alternaria solani.
[8]. The wavenumbers for the nCN band in the IR spectra of 2a-d are
greater than those in the spectra of the homoleptic anionic com-
plexes. These bands are observed in even smaller wavenumbers in
the spectra of the parent potassium dithiocarbimates [8,17,18]. The
NMR spectra show that the carbon atoms of the dithiocarbimate
group of 2a-d are more shielded than those of the anionic com-
plexes and the parent ligands. These facts are in accord with an
increase of the CN double bond character in the heteroleptic
complexes.
Compounds/Fungi
IC50 (mmol/L)
C. acutatum
B. cinerea
A. solani
2a
2b
2c
2d
0.52
0.46
0.40
0.41
0.53
0.50
0.42
0.33
0.33
0.61
0.31
0.30
0.31
0.24
0.36
PPh3

A.E.C. Vidigal et al. / Journal of Molecular Structure 1114 (2016) 21e29
29
[7] L.M.G. Cunha, M.M.M. Rubinger, M.R.L. Oliveira, E.C. Tavares, J.R. Sabino,
E.B.A.V. Pacheco, L.L.Y. Visconte, Inorg. Chim. Acta 383 (2012) 194.
[8] L.M.G. Cunha, M.M.M. Rubinger, J.R. Sabino, L.L.Y. Visconte, M.R.L. Oliveira,
Polyhedron 29 (2010) 2278.
The N-alkylsulfonyldithiocarbimate-nickel(II) complexes con-
taining triphenylphosphine (2a-d) inhibited the growth of B. cin-
erea, C. acutatum and A. solani while the complexes with dppe (3a-
d) were much less active. These results indicated that the mode of
action of the complexes might include the intracellular release of
the phosphines. An increased activity of the more lipophilic com-
pounds containing the longer dithiocarbimate aliphatic chain (R
with 8 carbon atoms), suggested that the stronger interaction with
the cell membrane is also important for the activity of these
complexes.
ꢀ
[9] M.R.L. Oliveira, H.P. Vieira, G.J. Perpetuo, J. Janczak, V.M. De Bellis, Polyhedron
21 (2002) 2243.
[10] M.R.L. Oliveira, J.A. Amim Jr., I.A. Soares, V.M. De Bellis, C.A. Simone, C. Novais,
S. Guilardi, Polyhedron 27 (2008) 727.
[11] M.R.L. Oliveira, E.F. Franca, C. Novais, S. Guilardi, I. Machado Jr., J. Ellena,
J.A. Amim Jr., V.M. De Bellis, M.M.M. Rubinger, Inorg. Chim. Acta 376 (2011)
238.
[12] N. Singh, B. Singh, K. Thapliyal, M.G.B. Drew, Inorg. Chim. Acta 363 (2010)
3589.
[13] (a) Y. Elad, B. Williamson, P. Tudzynski, N. Delen, Botrytis - Biology, Pathology
and Control, Springer, Dordrecht, 2004, pp. 1e8;
Acknowledgments
(b) M. Choquer, E. Fournier, C. Kunz, C. Levis, J.M. Pradier, A. Simon, M. Viaud,
Microbiol. Lett. 277 (2007), 1; M. Leroch, C. Plesken, R. W. S. Weber, F. Kauff, G.
Scalliet, M. Hahna, Appl. Environ. Microbiol. 79 (2013) 159.
We are grateful to the Conselho Nacional de Desenvolvimento
~
[14] (a) B.S.G. Paredes, F.R. Munoz, Crop Prot. 21 (2002) 11;
ꢀ
~
Científico e Tecnologico (CNPq), Coordenaçao de Aperfeiçoamento
(b) S. Freeman, F. Nizani, S. Dotan, S. Even, T. Sando, Plant Dis. 81 (1997) 749.
[15] (a) R. Chaerani, R.E. Voorrips, J. Gen. Plant Pathol. 72 (2006) 335;
(b) A. Horsfield, T. Wicks, K. Davies, D. Wilson, S. Paton, Australas. Plant Pathol.
39 (2010) 368.
[16] A.J. De Lucca, Rev. Iberoam. Micol. 24 (2007) 3.
[17] M.R.L. Oliveira, V.M. De Bellis, Trans. Metal. Chem. 24 (1999) 127.
[18] E.F. Franca, M.R.L. Oliveira, S. Guilardi, R.P. Andrade, R.H. Lindemann,
J.A. Amim Jr., J. Ellena, V.M. De Bellis, M.M.M. Rubinger, Polyhedron 25 (2006)
2119.
[19] Z. Otwinowski, W. Minor, in: C.W. Carter Jr., R.M. Sweet (Eds.), Methods in
Enzymology, vol. 276, Academic Press, New York, 1997, p. 307.
[20] A.L. Spek, Acta Cryst. D. 65 (2009) 148.
[21] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, J. Appl. Cryst. 27
(1994) 435.
~
ꢁ
de Pessoal de Nível Superior (CAPES) and Fundaçao de Amparo a
Pesquisa do Estado de Minas Gerais (FAPEMIG) for students' grants
and financial support.
Supplementary material
CCDC 1441014 and 1441022 contains the supplementary crys-
tallographic data for 2b and 2c, respectively. These data can be
obtained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
[22] G.M. Sheldrick, SHELXL2014, University of Gottingen, Germany, 2014.
[23] R.H. Blessing, Acta Cryst. A 51 (1995) 33.
[24] L. Farrugia, J. Appl. Cryst. 45 (2012) 849.
Appendix A. Supplementary data
[25] F. Macrae, P.R. Edgington, P. McCabe, E. Pidcock, G.P. Shields, R. Taylor,
M. Towler, J. van de Streek, J. Appl, Cryst 39 (2006) 453.
[26] B.A. Prakasam, K. Ramalingan, M. Saravanan, G. Bocelli, A. Cantoni, Polyhedron
23 (2004) 77.
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.molstruc.2016.02.060.
[27] J.A.S. Bonfim, F.P. De Souza, C.A.L. Filgueiras, A.G. De Souza,
M.T.P. Gambardella, Polyhedron 22 (2003) 1567.
References
[28] B.A. Prakasam, K. Ramalingan, G. Bocelli, A. Cantoni, Bull. Chem. Soc. Jpn. 79
(2006) 113.
[29] R.S. Amim, M.R.L. Oliveira, G.J. Perpetuo, J. Janczak, L.D.L. Miranda,
[1] G. Hogarth, P. J, Prog. Inorg. Chem. 53 (2005) 71.
[2] P.J. Nieuwenhuizen, A. Ehlers, J.G. Haasnoot, S.R. Janse, J. Reedijk, E.J. Baerends,
J. Am. Chem. Soc. 121 (1999) 163.
ꢀ
M.M.M. Rubinger, Polyhedron 27 (2008) 1891.
ꢀ
[30] H.U. Hummel, U. Korn, Z. Naturforsch 44B (1989) 24.
[3] L.C. Alves, M.M.M. Rubinger, R.H. Lindemann, G.J. Perpetuo, J. Janczak,
ꢂ
ꢀ
[31] Z. Travnícek, P. Starha, R. Pastorek, J. Mol. Struct. 1049 (2013) 22.
[32] M. Etter, Acc. Chem. Res. 23 (1990) 120.
L.D.L. Miranda, L. Zambolim, M.R.L. Oliveira, J. Inorg. Biochem. 103 (2009)
1045.
[33] N. Singh, B. Singh, K. Thapliyal, M.G.B. Drew, Inorg. Chim. Acta 363 (2010)
3589.
[4] R.S. Amim, M.R.L. Oliveira, J. Janczak, M.M.M. Rubinger, L.M.M. Vieira,
L.C. Alves, L. Zambolim, Polyhedron 30 (2011) 683.
[34] N. Singh, B. Singh, S.K. Singh, M.G.B. Drew, Inorg. Chem. Commun. 13 (2010)
1451.
[35] H.V. Huynh, L.R. Wong, P.S. Ng, Organometallics 27 (2008) 2231.
[5] L.C. Dias, M.M.M. Rubinger, J.P. Barolli, J.D. Ardisson, I.C. Mendes, G.M. De
Lima, L. Zambolim, M.R.L. Oliveira, Polyhedron 47 (2012) 30.
[6] A.A. Oliveira, M.R.L. Oliveira, M.M.M. Rubinger, D.C. Rezende, L. Zambolim,
Quím. Nova 38 (2015) 757.