Synthesis, spectral, structural and computational studies on NiS4 and NiS2NP chromophores: Anagostic and C-H?π (chelate) interactions in [Ni(dtc)(PPh3)(NCS)] (dtc = N-(2-phenylethyl)-N-(4-methoxybenzyl)- dithiocarbamate an

Article abstract of DOI:10.1016/j.molstruc.2016.04.079

Bis(N-(2-phenylethyl)-N-substituted benzyldithiocarbamato-S,S′)nickel(II) (1-6) and (N-(2-phenylethyl)-N-substituted benzyldithiocarbamato-S,S′)(thiocyanato-N) (triphenylphosphine)nickel(II) (7-12) [substituted benzyl = 2HO-C₆H₄-CH

Full text of DOI:10.1016/j.molstruc.2016.04.079

Journal of Molecular Structure 1119 (2016) 385e395
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: http://www.elsevier.com/locate/molstruc
Synthesis, spectral, structural and computational studies on NiS4 and
NiS2NP chromophores: Anagostic and CeH⋯p (chelate) interactions
in [Ni(dtc)(PPh3)(NCS)] (dtc ¼ N-(2-phenylethyl)-N-(4-
methoxybenzyl)- dithiocarbamate and N-(2-phenylethyl)-N-(4-
chlorobenzyl)dithiocarbamate)
,
,
E. Sathiyaraj a b, P. Selvaganapathi a, S. Thirumaran a *, Samuele Ciattini c
a Department of Chemistry, Annamalai University, Annamalinagar 608 002, Tamilnadu, India
b Department of Chemistry, Kalasalingam University, Krishnankoil 626 126, India
c Centro di Cristallografia Strutturale, Polo Scientifio di Sesto Fiorentino, Via della Lastruccia No. 3, 50019 Sesto Fiorentino, Firenze, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Bis(N-(2-phenylethyl)-N-substituted
benzyldithiocarbamato-S,S0)nickel(II)
(1e6)
and
(N-(2-
phenylethyl)-N-substituted benzyldithiocarbamato-S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II)
(7e12) [substituted benzyl ¼ 2HOeC6H4eCH2e (1,7), 3HOeC6H4eCH2e (2,8), 4HOeC6H4eCH2e (3,9),
4CH3OeC6H4eCH2e (4,10), 4FeC6H4eCH2e (5,11), 4CleC6H4eCH2e (6,12)] complexes have been syn-
thesized and characterized by elemental analysis, IR, UVeVis and NMR (1H and 13C) spectroscopy. In the
case of heteroleptic complexes 7e12, the shift in vC-N values to higher wavenumber and the NCS2 carbon
signals are shifted to downfield compared to the homoleptic complexes indicating the increasing
Received 11 December 2015
Received in revised form
12 April 2016
Accepted 25 April 2016
Available online 30 April 2016
Keywords:
Nickel(II)
Dithiocarbamate
Triphenylphosphine
X-ray structure
Anagostic interactions
strength of thioureide vC-N bond due to the presence of
eroleptic complexes. Electronic spectral studies on all the complexes (1e12) suggest square planar ge-
ometry around the nickel(II). Structures of 10 and 12 have been elucidated by X-ray crystallography. The
p-accepting triphenylphosphine ligand in het-
dithiocarbamate anions in 10 and 12 chelate to the nickel atom. Both the structures reveal CeH
intramolecular anagostic interaction. CeH⋯p (chelate) is observed in complexes 10. Supramolecular
frame works are stabilised by CeH S, CeH⋯p and CeH Cl non-covalent interaction. The molecular
⋯Ni
⋯
⋯
geometry, HOMO-LUMO in the ground state and MEP have been calculated for 10 and 12 using Hartree-
Fock (HF) method with LANL2DZ basic set. Molecular electrostatic potential diagram of complexes 10 and
12 support the partial double bond character of CeN (thioureide) bond in dithiocarbamate ligands.
© 2016 Elsevier B.V. All rights reserved.
1. Introduction
field etc [2]. Dithiolate Ni(II) complexes, containing a coordination
NiS4 unit, are widely applied in analytical chemistry, organic syn-
The importance of coordination chemistry has now become
broad and the applications of coordination compounds to the sci-
entific world are tremendous [1]. Several donor atoms like oxygen,
sulfur, nitrogen, phosphorous were reported earlier by many
pioneer workers in this field. Metal-dithiocarbamate complexes are
the most widely studied. Because of the metal binding property and
their chelates vital role to biological, agricultural and industrial
thesis and biology. Dithiocarbamate ligands are used to extract
metals [3] and their complexes serve as precursors of metal-
sulfides in modern electronics [4e11]. Metal dithiocarbamate
complexes have numerous applications in the chemical, agricul-
tural and pharmaceutical industry, mainly because of their metal-
binding and antioxidant properties [12,13]. A number of bis(di-
thiocarbamate)nickel(II), [Ni(dtc)2] and [Ni(dtc)(NCS)(PPh3)] com-
plexes have been synthesized, several of them have been
characterized by single crystal X-ray diffraction [14,15]. Non-
covalent interactions are fundamental for supramolecular
* Corresponding author.
E-mail address: sthirumaran@yahoo.com (S. Thirumaran).
http://dx.doi.org/10.1016/j.molstruc.2016.04.079
0022-2860/© 2016 Elsevier B.V. All rights reserved.

386
E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
chemistry, drug design, protein folding, crystal engineering and
other areas of molecular science. The crystal engineering of mole-
cules is concerned with intriguing architectures and utilitarian
consideration. Non-covalent interactions, such as conventional
2.2.2. Preparation of (N-(2-phenylethyl)-N-substituted
benzyldithiocarbamato-S,S0)(thiocyanato-N)(triphenylphosphine)
nickel(II)
Bis(N-(2-phenylethyl)-N-substituted benzyldithiocarbamato-
S,S0)nickel(II) (1.0 mmol), PPh3 (2.0 mmol), NiCl2$6H2O (1.0 mmol)
and NH4SCN (2.0 mmol) were dissolved in chloroform-methanol
solvent mixture (3:2, 50 mL) and heated to reflux for 3 h. The
solution obtained was filtered off. Purple-red solid formed after 5
days. It was filtered off and recrystallized from chloroform
(Scheme 1).
XeH
hydrogen bonding, CeH⋯p
⋯p (chelate), CeH⋯p (chelate) and XeH
⋯
Y and non-conventional CeH
p⋯p (chelate)⋯p (chelate),
M (X ¼ O, N, C) metal
⋯
X (X or Y ¼ F, Cl, O, N, S)
,
,
p
p
(aryl)
⋯
assisted anagostic, agostic and hydrogen bonding interactions,
often play crucial roles in the molecular recognition processes and
organization of the supramolecular networks [16e30]. Our aim is to
study the non-covalent interactions in homoleptic and heteroleptic
Ni(II) complexes involving functionalized dithiocarbamate com-
plexes. In this paper, we report the synthesis and characterization
of some Ni(II) complexes containing N-(2-phenylethyl)-N-
substituted benzyl dithiocarbamates. In addition, Single crystal X-
ray structural analysis and computational studies on (N-(2-
2.2.2.1. bis(N-(2-phenylethyl)-N-(2-hydroxybenzyl)dithiocarbamato-
S,S0)nickel(II) (1). Yield 78%, mp 230e231 ꢁC. IR (KBr, cmꢀ1):
n
¼ 3453 (nOH); 1510 (nCeN); 1026 (nCeS). UVeVis (CH3CN, nm):
l
¼ 621, 478, 394, 337, 285, 250. 1H NMR (400 MHz, DMSO,
ppm):
d
¼
2.83 (b, 4H, (C6H5eCH2eCH2eN)); 3.68 (b, 4H,
phenylethyl)-N-4-methoxy
benzyldithiocarbamato-
C6H5eCH2eCH2eN); 4.71 (s, 4H, 2HOeC6H4eCH2eN); 6.83e7.30
S,S0)(thiocyanato-N)(triphenylphosphine)nickel(II) (10) and (N-(2-
phenylethyl)-N-4-chlorobenzyldithiocarbamato-S,S0)(thiocyanato-
N)(triphenylphosphine)nickel(II) (12) are also presented.
(aromatic protons); 9.99 (s, 2H, 2HOeC6H4eCH2eN). 13C NMR
(100 MHz, DMSO, ppm):
d
¼ 32.5 (C6H5eCH2eCH2eN); 47.4
(C6H5eCH2eCH2eN); 50.4 (2HOeC6H4eCH2eN); ipso carbon; 155.5
(Are2OH); 115.3e137.5 (other aromatic carbons); 205.2 (NCS2);
Anal. Calcd. for Chemical Formula: C32H32N2NiO2S4 (%): Elemental
Analysis: C, 57.92; H, 4.86; N, 4.22; Found: C, 57.13; H, 4.61; N, 4.07.
2. Experimental
2.2.2.2. bis(N-(2-phenylethyl)-N-(3-hydroxybenzyl)dithiocarba-
2.1. Materials and instrumentation
mato-S,S0)nickel(II) (2). Yield 66%, mp 156e158 ꢁC. IR (KBr,
cmꢀ1):
nm):
ppm):
n
¼ 3370 (nOH); 1501 (nCeN); 1022 (nCeS). UVeVis (CH3CN,
All reagents and solvents were commercially available high
grade materials (Merck/sd Fine/Himedia) and used as received. FT-
IR spectra were recorded on a SHIMADZU FT-IR spectrophotometer
(range 400e4000 cmꢀ1) as KBr pellets. 1H NMR spectra were
recorded on Bruker 400 MHz and 13C NMR spectra on Bruker
100 MHz in CDCl3 and DMSO-d6 as a solvent and tetramethylsilane
(TMS) as an internal standard. For compounds 1e3 dissolved in
DMSO-d6, the two signals of DMSO and water arose at 2.5 and
3.4 ppm, respectively. SHIMADZU UV-1650 PC double beam
UVevisible spectrophotometer was used for recording the elec-
tronic spectra of the complexes. The spectra were recorded in
acetonitrile, chloroform and the pure solvents were used as the
reference.
l
¼ 618, 479, 394, 330, 283, 250. 1H NMR (400 MHz, DMSO,
d
¼
2.84 (b, 4H, (C6H5eCH2eCH2eN)); 3.65 (b, 4H,
(C6H5eCH2eCH2eN)); 4.71 (s, 4H,3HOeC6H4eCH2eN); 6.74e7.31
(aromatic protons); 9.64 (s, 2H,3HOeC6H4eCH2eN); 13C NMR
(100 MHz, DMSO, ppm):
d
¼ 32.4 (C6H5eCH2eCH2eN); 50.2
(C6H5eCH2eCH2eN); 51.8 (3HOeC6H4eCH2eN); ipso car-
bon;157.7 (Are3OH); 114.6e137.5 (other aromatic carbons); 205.7
(NCS2); Anal. Calcd. for Chemical Formula: C32H32N2NiO2S4 (%):
Elemental Analysis: C, 57.92; H, 4.86; N, 4.22; Found: C, 57.94; H,
4.69; N, 4.07.
2.2.2.3. bis(N-(2-phenylethyl)-N-(4-hydroxybenzyl)dithiocarba-
mato-S,S0)nickel(II) (3). Yield 75%, mp 176e178 ꢁC. IR (KBr, cmꢀ1):
n
¼ 3360 (nOH); 1503 (nCeN); 1020 (nCeS). UVeVis (CH3CN, nm):
l
¼ 618, 478, 435, 393, 313, 275, 252, 246. 1H NMR (400 MHz,
DMSO, ppm):
d
¼ 2.79 (b, 4H, (C6H5eCH2eCH2eN)); 3.61 (b, 4H,
2.2. Syntheses of nickel(II) complexes
(C6H5eCH2eCH2eN)); 4.67 (s, 4H,4HOeC6H4eCH2eN); 6.79e7.30
(aromatic protons); 9.64 (s, 2H,4HOeC6H4eCH2eN); 13C NMR
2.2.1. Preparation of bis(N-(2-phenylethyl)-N-substituted
(100 MHz, CDCl3, ppm):
d
¼ 32.4 (C6H5eCH2eCH2eN); 49.8
benzyldithiocarbamato-S,S0)nickel(II)
(C6H5eCH2eCH2eN); 51.5 (4HOeC6H4eCH2eN); ipso carbon;
157.4 (Are4OH); 115.4e137.5 (other aromatic carbons); 204.9
(NCS2); Anal. Calcd. for Chemical Formula: C32H32N2NiO2S4 (%):
Elemental Analysis: C, 57.92; H, 4.86; N, 4.22; Found: C, 57.37; H,
4.87; N, 4.11.
2-phenylethylamine (4.6 mmol) in methanol was added to
substituted benzaldehyde (2-OH, 3-OH, 4-OH, 4-OCH3, 4-F and 4-
Cl) (5.1 mmol) in methanol and the solution was stirred continu-
ously for 2 h. The colourless oil formed on evaporation of the sol-
vent. The product was dissolved in methanol-dichloromethane
solvent mixture (1:1, 20 mL) and sodium borohydride (13.8 mmol)
was added slowly and stirred continuously for 2 h under ice cold
condition (5 ꢁC). Further, the mixture was stirred for 20 h at room
temperature. After evaporation of the solvent, the resulting viscous
liquid product was washed with water and the product was
extracted with dichloromethane. Evaporation of the organic layer
yielded N-(2-phenylethyl)-N-substituted benzylamine as pale yel-
low oil. N-(2-phenylethyl)-N-substituted benzylamine (4 mmol)
and carbon disulfide (4.0 mmol) were dissolved in ethanol (20 mL)
and stirred for 30 min. Nickel chloride hexahydrate (2.0 mmol) was
dissolved in 10 mL of water and added to the solution with constant
stirring. The complexes formed were filtered off, dried and
recrystallized from acetonitrile (Scheme 1).
2.2.2.4. bis(N-(2-phenylethyl)-N-(4-methoxybenzyl)dithiocarba-
mato-S,S0)nickel(II) (4). Yield 81%, mp 182e184 ꢁC. IR (KBr, cmꢀ1):
n
¼ 1506 (nCeN); 1022 (nCeS). UVeVis (CHCl3, nm):
l
¼ 629, 502, 393,
328, 261. 1H NMR (400 MHz, CDCl3, ppm):
d
¼ 2.88 (b, 4H,
(C6H5eCH2eCH2eN)); 3.65 (b, 4H, (C6H5eCH2eCH2eN)); 3.81 (s,
3H,4CH3OeC6H4eCH2eN); 4.58 (s, 4H,4CH3OeC6H4eCH2eN);
6.87e7.30 (aromatic protons); 13C NMR (100 MHz, CDCl3, ppm):
d
¼ 33.4 (C6H5eCH2eCH2eN); 50.1 (C6H5eCH2eCH2eN); 52.3
(4CH3OeC6H4eCH2eN); 55.4 (4CH3OeC6H4eCH2eN); ipso carbon;
159.7 (Are4OCH3); 114.3e137.7 (other aromatic carbons); 207.9
(NCS2); Anal. Calcd. for Chemical Formula: C34H36N2NiO2S4 (%):
Elemental Analysis: C, 59.04; H, 5.25; N, 4.05; Found: C, 58.46; H,
4.99; N, 4.00.

E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
387
2.2.2.7. (N-(2-phenylethyl)-N-(2-hydroxybenzyl)dithiocarbamato-
S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II) (7). Yield 80%,
mp 180e182 ꢁC. IR (KBr, cmꢀ1):
(
n
¼ 3240 (nOH); 1520 (nCeN); 2099
nNCS); 1024 (nCeS). UVeVis (CH3CN, nm):
¼ 483, 331, 274, 257.
1H NMR (400 MHz, DMSO, ppm):
l
d
¼ 2.69, 2.81 (bd, 4H,
(C6H5eCH2eCH2eN)); 3.49, 3.65 (bd, 4H, (C6H5eCH2eCH2eN));
4.56, 4.75 (bd, 4H, 2HOeC6H4eCH2eN); 6.86e7.71 (aromatic
protons); 13C NMR (100 MHz, CDCl3, ppm):
d
¼
33.4
50.9
(C6H5eCH2eCH2eN);
47.5
(C6H5eCH2eCH2eN);
(2HOeC6H4eCH2eN); ipso carbon; 154.9 (Are2OH); 116.1e137.3
(other aromatic carbons); 143.2(NCS); 203.6 (NCS2); Anal. Calcd.
for Chemical Formula: C35H31N2NiOPS3 (%): Elemental Analysis:
C, 61.68; H, 4.58; N, 4.11; Found: C, 61.32; H, 4.50; N, 3.99.
2.2.2.8. (N-(2-phenylethyl)-N-(3-hydroxybenzyl)dithiocarbamato-
S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II) (8). Yield 78%,
mp 151e153 ꢁC. IR (KBr, cmꢀ1):
n
¼ 3323 (nOH); 2097 (nCeN); 1518
(
nCeN); 1022 (nCeS). UVeVis (CH3CN, nm):
l
¼ 484, 332, 260. 1H
NMR (400 MHz, DMSO, ppm): 2.71, 2.81 (bd, 4H,
d
¼
(C6H5eCH2eCH2eN)); 3.46, 3.64 (bd, 4H, (C6H5eCH2eCH2eN));
4.36,4.57 (bd, 4H, 3HOeC6H4eCH2eN); 6.61e7.73 (aromatic
protons); 13C NMR (100 MHz, CDCl3, ppm):
d
¼
33.4
52.6
(C6H5eCH2eCH2eN);
50.4
(C6H5eCH2eCH2eN);
(3HOeC6H4eCH2eN); ipso carbon;156.8 (Are3OH); 115.6e137.1
(other aromatic carbons); 143.5 (NCS); 204.7 (NCS2); Anal. Calcd.
for Chemical Formula: C35H31N2NiOPS3 (%): Elemental Analysis:
C, 61.68; H, 4.58; N, 4.11; Found: C, 61.25; H, 4.62; N, 3.92.
2.2.2.9. (N-(2-phenylethyl)-N-(4-hydroxybenzyl)dithiocarbamato-
S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II) (9). Yield 74%,
mp 194e196 ꢁC. IR (KBr, cmꢀ1):
n
¼ 3248 (nOH); 2100 (nNCS); 1512
(
nCeN); 1015 (nCeS). UVeVis (CH3CN, nm):
l
¼ 482, 333, 273, 254.
1H NMR (400 MHz, DMSO, ppm):
d
¼
2.67, 2.81 (bd, 4H,
(C6H5eCH2eCH2eN)); 3.43, 3.60 (bd, 4H, (C6H5eCH2eCH2eN));
4.34, 4.55 (bd, 4H, 4HOeC6H4eCH2eN); 6.82e7.64 (aromatic
Scheme 1. Preparation of homoleptic and heteroleptic nickel(II) complexes 1e12.
protons); 13C NMR (100 MHz, DMSO, ppm):
d
¼
33.4
52.3
(C6H5eCH2eCH2eN);
50.1
(C6H5eCH2eCH2eN);
(4HOeC6H4eCH2eN); ipso carbon;156.2 (Are4OH); 116.0e137.2
(other aromatic carbons); 204.5 (NCS2); Anal. Calcd. for Chemical
Formula: C35H31N2NiOPS3 (%): Elemental Analysis: C, 61.68; H,
4.58; N, 4.11; Found: C, 61.33; H, 4.39; N, 4.01.
2.2.2.5. bis(N-(2-phenylethyl)-N-(4-fluorobenzyl)dithiocarbamato-
S,S0)nickel(II) (5). Yield 77%, mp 178e180 ꢁC. IR (KBr, cmꢀ1):
n
¼ 1504 (nCeN); 1020 (nCeS). UVeVis (CHCl3, nm):
l
¼ 637, 498,
394, 328, 263. 1H NMR (400 MHz, CDCl3, ppm):
d
¼ 2.91(b, 4H,
2.2.2.10. (N-(2-phenylethyl)-N-(4-methoxybenzyl)dithiocarbamato-
S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II) (10). Yield 76%,
(C6H5eCH2eCH2eN)); 3.67 (b, 4H, (C6H5eCH2eCH2eN)); 4.59 (s,
4H,4FeC6H4eCH2eN); 7.03e7.31 (aromatic protons); 13C NMR
mp 186e187 ꢁC. IR (KBr, cmꢀ1):
n
¼ 2091 (nNCS); 1514 (nCeN); 1026
(100 MHz, CDCl3, ppm):
d
¼ 33.4 (C6H5eCH2eCH2eN); 50.3
(nCeS). UVeVis (CHCl3, nm):
l
¼ 483, 329, 260. 1H NMR (400 MHz,
(C6H5eCH2eCH2eN); 52.0 (4FeC6H4eCH2eN); ipso carbon; 161.5,
163.9 (Ar-4F); 115.9e137.6 (other aromatic carbons); 208.6
(NCS2); Anal. Calcd. for Chemical Formula: C32H30F2N2NiS4 (%):
Elemental Analysis: C, 57.58; H, 4.53; N, 4.20; Found: C, 57.08; H,
4.23; N, 4.10.
CDCl3, ppm):
d
¼ 2.67, 2.83 (bd, 4H, (C6H5eCH2eCH2eN)); 3.44, 3.62
(bd, 4H, (C6H5eCH2eCH2eN)); 3.80 (s, 3H, 4CH3OeC6H4eCH2eN);
4.37, 4.57 (bd, 4H, 4CH3OeC6H4eCH2eN); 6.86e7.74 (aromatic
protons); 13C NMR (100 MHz, CDCl3, ppm):
d
¼
33.5
52.3
(C6H5eCH2eCH2eN);
50.1
(C6H5eCH2eCH2eN);
(4CH3OeC6H4eCH2eN); 55.4 (4CH3OeC6H4eCH2eN); ipso carbon;
159.9 (Are4OCH3); 114.5e137.2 (other aromatic carbons); 204.2
(NCS2); Anal. Calcd. for Chemical Formula: C36H33N2NiOPS3 (%):
Elemental Analysis: C, 62.17; H, 4.78; N, 4.03; Found: C, 61.88; H,
4.60; N, 3.84.
2.2.2.6. bis(N-(2-phenylethyl)-N-(4-chlorobenzyl)dithiocarbamato-
S,S0)nickel(II) (6). Yield 78%, mp 196e198 ꢁC. IR (KBr, cmꢀ1):
n
¼ 1499 (nCeN); 1020 (nCeS). UVeVis (CHCl3, nm):
l
¼ 631, 498, 393,
329, 265. 1H NMR (400 MHz, CDCl3, ppm):
d
¼ 2.91(b, 4H,
2.2.2.11. (N-(2-phenylethyl)-N-(4-fluorobenzyl)dithiocarbamato-
S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II) (11). Yield 79%,
(C6H5eCH2eCH2eN)); 3.67 (b, 4H, (C6H5eCH2eCH2eN)); 4.58 (s,
4H,4CleC6H4eCH2eN); 7.17e7.34 (aromatic protons); 13C NMR
mp 169e171 ꢁC. IR (KBr, cmꢀ1):
n
¼ 2089 (nNCS); 1510 (nCeN); 1018
(100 MHz, CDCl3, ppm):
(C6H5eCH2eCH2eN); 52.1 (4CleC6H4eCH2eN); 127.0e137.5 (aro-
matic carbons); 208.9 (NCS2): Anal. Calcd. for Chemical Formula:
d
¼ 33.4 (C6H5eCH2eCH2eN); 50.4
(
nCeS). UVeVis (CHCl3, nm):
l
¼ 487, 332, 253. 1H NMR (400 MHz,
CDCl3, ppm):
d
¼ 2.78 (b, 4H, (C6H5eCH2eCH2eN)); 3.51 (b, 4H,
(C6H5eCH2eCH2eN)); 4.50 (b, 4H,4FeC6H4eCH2eN); 7.04e7.71
C
32H30Cl2N2NiS4 (%): Elemental Analysis: C, 54.87; H, 4.32; N, 4.00;
(aromatic protons); 13C NMR (100 MHz, CDCl3, ppm):
(C6H5eCH2eCH2eN); 50.3 (C6H5eCH2eCH2eN);
d
¼ 33.5
Found: C, 54.51; H, 4.18; N, 4.03.
52.3

388
E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
22
(4FeC6H4eCH2eN); ipso carbon; 161.5, 164.0 (Ar-4F); 116.0e137.1
(other aromatic carbons); 205.2 (NCS2); Anal. Calcd. for Chemical
Formula: C35H30FN2NiPS3 (%): Elemental Analysis: C, 61.50; H,
4.22; N, 4.10; Found: C, 61.09; H, 4.06; N, 3.86.
and dxy / d
(ca. 620 nm) transitions. Bands observed around
xey
480 nm for complexes (7e12) can be attributed to d2z/dxy / d
transitions. These ded transitions in homoleptic and heteroleptic
complexes (1e12) indicate that the geometry in the vicinity of the
nickel atom is probably square planar [42].
22
xey
2.2.2.12. (N-(2-phenylethyl)-N-(4-chlorobenzyl)dithiocarbamato-
S,S0)(thiocyanato-N) (triphenylphosphine)nickel(II) (12). Yield 78%,
3.3. NMR spectral studies
mp 164e166 ꢁC. IR (KBr, cmꢀ1):
n
¼ 2089 (nNCS); 1514 (nCeN); 1022
¼ 485, 335, 259. 1H NMR (400 MHz,
3.3.1. 1H NMR spectral studies
(
nCeS). UVeVis (CHCl3, nm):
l
CDCl3, ppm):
d
¼ 2.71, 2.86, (bd, 4H, (C6H5eCH2eCH2eN)); 3.45,
For all the complexes 1e12, a singlet or two broad signals
observed in the region 4.30e4.75 ppm are assigned to the methy-
lene protons of substituted benzyl group. All the complexes show
two sets of signals in the region 3.40e3.68 and 2.67e2.91 ppm
associated with methylene protons of ethyl group of phenylethyl;
that bound to nitrogen appearing at relatively lowfield. The signals
due to the methylene protons adjacent to nitrogen atom are
deshielded on complexation. The other proton signals are not
greatly affected in all the complexes because of the relative distance
3.64 (bd, 4H, (C6H5eCH2eCH2eN)); 4.37, 4.59 (bd, 4H,
4CleC6H4eCH2eN); 6.99e7.73 (aromatic protons); 13C NMR
(100 MHz, CDCl3, ppm):
d
¼ 33.4 (C6H5eCH2eCH2eN); 50.4
(C6H5eCH2eCH2eN); 52.3, 51.9 (4CleC6H4eCH2eN); 127.2e137.0
(aromatic carbons); 144.0 (NCS); 205.7 (NCS2); Anal. Calcd. for
Chemical Formula: C35H30ClN2NiPS3 (%): Elemental Analysis: C,
60.06; H, 4.32; N, 4.00; Found: C, 59.80; H, 4.11; N, 3.88.
2.3. X-ray diffraction analysis
from the thioureide p-system [43].
Each methylene protons of dithiocarbamate in heteroleptic
complexes 7e12 are appeared as a broad or two broad signals due
to the fast isothiocyanate ligand exchange process as observed in
[Ni(dtc)(PPh3)(NCS)] [44]. In the complexes 1e3, a singlet observed
in the downfield around 10.0 ppm is assigned to the hydroxyl
proton. CDCl3 was used as a solvent to record 1H NMR spectra of
complexes 7e9. In these cases, the OH proton signal merged with
the aromatic proton signals. A singlet observed at 3.80 ppm in
complexes 4 and 10 is due to the methoxy methyl protons. In the
aromatic region, a triplet at 7.05 ppm and a broad signal at
7.04 ppm are observed for complexes 5 and 11, respectively. These
signals correspond to the protons ortho to fluorine atom. Apart
from these signals, signals observed in the region 6.61e7.73 ppm
are due to the phenyl ring protons.
Intensity data for the crystals of 10 and 12 were collected on an
Xcalibur Sapphire3 with CCD diffractometer instrument, using
graphite monochromated MoK
a
radiation (
l
¼ 0.71073 Å). Cell
parameters were determined by least-squares refinement of the
diffraction data. The structures were solved with direct methods
with SHELXS97 [31] and refined by full-matrix least squares pro-
cedures on F2 with SHELXL97 [32]. All the non-hydrogen atoms
were refined anisotropically and the hydrogen atoms were refined
isotropically.
3. Results and discussion
3.1. Infrared spectral studies
3.3.2. 13C NMR spectral studies
In the IR spectra of metal-dithiocarbamate complexes, the
bands due to the nCeN and nCeS stretching modes are important.
In the case of dithiocarbamates, nCeN appears usually in the re-
gion 1450e1550 cmꢀ1, an intermediate value between those of a
typical single and double bonded CeN bonds. In the present
study, IR spectra of complexes 1e12 reveal a band in the region
1499e1520 cmꢀ1 assigned to the nCeN vibration [33]. This band is
characteristic of NeC(S2) bond with an intermediate bond order
between a single and double bond. The bands in the region
950e1050 cmꢀ1 are diagnostic in deciding the coordination
mode (monodentate or bidentate) of dithiocarbamate [34]. In
this investigation, a single band is observed in the region
1015e1026 cmꢀ1. This confirms that the coordination of the bisN-
(2-phenylethyl)-N-substituted benzyldithiocarbamate ligands to
the nickel atom corresponds to a bidentate mode. The observed
stretching frequency around 2090 cmꢀ1 for heteroleptic com-
plexes 7e12 is attributed to the N-coordinated thiocyanate
[35e39]. The OeH stretching vibrations appear around
3240e3253 cmꢀ1 in the complexes 1e3 and 7e9.
Complexes 1e12 exhibit three signals in the aliphatic region
associated with the methylene carbons of dithiocarbamates. The
signal for methylene carbon of benzyl group appears around
50.0 ppm. The remaining two signals in the aliphatic region are
due to the methylene carbons of ethylene unit of phenylethyl
group of dithiocarbamate that bound nitrogen atom appearing at
relatively highfield. Phenyl ring carbons of dithiocarbamate li-
gands and triphenylphosphine are observed in the region
114.0e164.0 ppm.
13C NMR signals of the dithiocarbamate carbons (NCS2) appear
from 203.0 to 209.0 ppm for complexes 1e12. The upfield shift of
NCS2 carbon signals for heteroleptic complexes 10e12
(204.5e205.7 ppm) compared to the homoleptic complexes 4e6
(207.9e208.9 ppm) is ascribed to increase of
p-bond character. This
is due to the presence of -acid (triphenylphosphine) in hetero-
p
leptic complexes which increases the mesomeric drift of electron
density from the dithiocarbamate moiety towards the metal atom
[45]. Comparison of the NCS2 chemical shifts of heteroleptic com-
plexes 7e9 with homoleptic complexes 1e3 is not possible because
the 13C NMR spectra of these complexes were recorded in different
solvents.
3.2. Electronic spectral studies
The bands appear in the UV region of electronic spectra of
homoleptic and heteroleptic complexes 1e12 are ascribed to the
A very weak signal observed around 143.0 ppm for complexes
7, 8 and 12 are assigned to the carbon of thiocyanate. A signal in
the downfield region 154.9e159.9 ppm for complexes 1e4 and
7e10 are assigned to ipso carbon of the OH and methoxy func-
tion in the phenyl ring. 13C NMR spectra of the complexes 5 and
11 show two signal around 161.0 and 164.0 ppm due to the ipso
carbon.
intramolecular intraligand transitions corresponding to
p/p*
transitions of the NeC]S, SeC]S groups and n/ * transition
p
located on the sulfur atom [40,41]. The electronic spectra of the
complexes (1e6) show two weak ded bands around 480 and
22
620 nm. These bands can be assigned to the d2z / d
(ca. 480 nm)
xey

E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
389
Table 1
Crystal data, data collection and refinement parameters for 10 and 12.
10
12
Empirical formula
C36 H33 N2 Ni O P S3
C35 H30 Cl N2 Ni P S3
FW
695.50
699.92
Crystal dimensions (mm)
0.35 ꢂ 0.30 ꢂ 0.20
0.5 ꢂ 0.4 ꢂ 0.3
Crystal system
Space group
a/Å
Monoclinic
monoclinic
P 21/n
10.087(1)
P21/n
9.820(1)
b/Å
20.104(1)
20.399(1)
c/Å
17.551(1)
90.00
104.72(1)
90.00
17.425(1)
90.00
102.877(3)
90.00
ꢁ
a
b
g
/
/
/
ꢁ
ꢁ
V/Å3
3442.3(4)
3402.8(4)
Z
4
4
Dc/g cmꢀ3
1.342
0.823
1.366
0.907
m
/cmꢀ1
F(000)
1448
1448
l
/Å
MoKa (0.71073)
4.13e29.03
MoKa (0.7107)
4.25e29.23
ange/ꢁ
Index ranges
ꢀ13 ꢃ h ꢃ 13, ꢀ26 ꢃ k ꢃ 25, ꢀ23 ꢃ l ꢃ 22
ꢀ11 ꢃ h ꢃ 13, ꢀ25 ꢃ k ꢃ 26, ꢀ23 ꢃ l ꢃ 22
Reflections collected
Observed reflections I > 2
Weighting scheme
23663
23005
s
(I) 4592
Calc. W ¼ 1/(
8022, 5005
s
2(F2o) þ (0.0477p)2 þ 0.7371p) where p ¼ (Fo2 þ 2F2c)/3 Calc. W ¼ 1/(
s
2(Fo2) þ (0.0544p)2 þ 0.6468p) where p ¼ (Fo2 þ 2F2c)/3
Number of parameters refined 352
388
R[F2 > 2
s
(F2)], wR(F2)
0.0315, 0.0827
0.957
0.0541, 0.1180
1.030
GOOF
3.4. Single crystal X-ray structural analysis
90ꢁ due to the chelation of dithiocarbamate ligand. The structure
consists of distorted square planar metal coordination with
NiS2PN chromophore. Based on the value of t4 (0.07), the coor-
dination geometries of 10 and 12 are described as being 7% along
the pathway of distortion from perfect square planar to seesaw
structure [46]. The NieS bond distances [NieS1 ¼ 2.2291(9) and
NieS2 ¼ 2.1634(9) Å] for 10 and [NieS1 ¼ 2.1702(10) and
NieS2 ¼ 2.2245(9) Å] for 12 are significantly different. The NieS
bond trans to PPh3 is longer than the other NieS bond. This is
owing to the greater trans effect of triphenylphosphine compared
to those of the NCSꢀ [35e39]. The average CeS bond lengths
[1.721(3) and 1.715 (3) for 10 and 12, respectively] and CeN bond
length [1.312(4) and 1.318(4) Å for 10 and 12, respectively] are in
the range those established for the CeS partial double bond and
CeN (thioureide) bond in dithiocarbamates [47].
3.4.1. Structural analysis of complexes 10 and 12
Details of the crystal data, data collection and refinement
parameters for 10 and 12 are summarized in Table 1. Single
crystals of 10 and 12 were obtained by the slow evaporation of
dichloromethane: acetonitrile and chloroform: acetonitrile so-
lution, respectively. The intensity data were collected at 150(2) K
for 10 and 293(2) K for 12. The ORTEP diagrams are shown in
Figs. 1 and 2. Selected bond distances and angles are given in
Table 2.
In both the complexes 10 and 12, the nickel cation is coordi-
nated by two sulfur atoms from dithiocarbamate ligands, one
nitrogen atom from thiocyanate and one phosphorus atom from
PPh3 into a distorted square planar configuration. The angles
S1eNieP1, N2eNieP1 and N2eNieS2 are less distorted from 90ꢁ
than the angle S1eNieS2. The S1eNieS2 angle is smaller than
The NieN distances [1.866(3) and 1.860(3) Å for 10 and 12,
respectively] are quite short, showing the effective bonding be-
tween the nickel atom and the thiocyanate-N. The CeS bond
lengths in thiocyanate is 1.617(4) and 1.620(4) Å for 10 and 12,
Fig. 1. ORTEP diagram of complex 10.
Fig. 2. ORTEP diagram of complex 12.

390
E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
Table 2
Selected bond distances (Å) and angles (ꢁ) for complexes 10 and 12.
10
12
Bond distances (Å)
Bond distances (Å)
Ni1eN2
Ni1eS2
Ni1eP1
Ni1eS1
S2eC1
1.866(3)
2.1634(9)
2.1871(9)
2.2291(9)
1.726(3)
1.715(3)
1.617(4)
1.150(4)
1.312(4)
Ni1eN2
Ni1eS1
Ni1eP1
Ni1eS2
S1eC19
S2eC19
S3eC36
C19eN1
C36eN2
1.860(3)
2.1702(10)
2.1903(8)
2.2245(9)
1.722(3)
1.708(3)
1.620(4)
1.318(4)
1.150(4)
S1eC1
S3eC36
C36eN2
N1eC1
Bond angles (ꢁ)
Bond angles (ꢁ)
N2eNi1eS2
N2eNi1eP1
S2eNi1eP1
N2eNi1eS1
S2eNi1eS1
P1eNi1eS1
C1eS2eNi1
C1eS1eNi1
N2eC36eS3
N1eC1eS1
N1eC1eS2
S1eC1eS2
174.86(8)
88.99(8)
95.95(3)
95.99(8)
79.11(3)
174.77(4)
86.67(11)
84.87(11)
178.3(3)
125.6(2)
125.6(3)
108.82(18)
172.3(3)
N2eNi1eS1
N2eNi1eP1
S1eNi1eP1
N2eNi1eS2
S1eNi1eS2
P1eNi1eS2
C19eS1eNi1
C19eS2eNi1
N1eC19eS2
N1eC19eS1
S2eC19eS1
N2eC36eS3
C36eN2eNi1
174.62(8)
88.89(8)
96.28(3)
95.98(8)
174.96(4)
86.66(12)
85.29(11)
125.8(2)
125.2(3)
109.00(18)
179.0(3)
171.0(3)
Fig. 4. Intermolecular S⋯HeC interactions in complex 10.
C36eN2eNi1
Table 3
Geometric details of hydrogen bonding (Å,º) in complex 10.
Interactions
DeH
H⋯A
D⋯
A
DeH⋯A
C19eH19/Ni1a
0.93
0.97
0.97
0.93
0.93
0.93
2.967
2.565
2.677
2.997
2.912
2.995
3.512(3)
3.095(4)
3.072(4)
3.714(4)
3.857(4)
3.919(4)
119.00
114.40
104.36
135.11
165.15
172.26
C2eH2A⋯
S2b
C10eH10A⋯
S1b
C22eH22/S1c
C2eH2B/S3c
C4eH4/S3c
a
Intramolecular anagostic interaction.
Intramolecular hydrogen bonding.
Intermolecular hydrogen bonding.
b
c
complexes are (i). agostic (ii). anagostic or preagostic (Scheme 2)
and (iii) hydrogen bonding. Agostic interactions are 3ce2e
Scheme 2. Geometric difference between (a) agostic and (b) anagostic interaction.
bonding interactions with <M
~90e140ꢁ and M
H distances in the range ~1.8e2.3 Å. Anagostic
interactions are somewhat weaker than agostic interaction. They
⋯HeC angles in the range
⋯
respectively which is similar to the C]S distance of 1.69 Å. The
NieP distance is similar to those found in other
[Ni(dtc)(NCS)(PPh3)] complexes [35e39].
Three types CeH⋯M interactions observed in transition metal
Fig. 3. Intramolecular CeH
⋯
Ni anagostic interaction in complex 10.
Fig. 5. Intramolecular S⋯HeC interactions in complex 10.

E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
391
are characterized by long M
<M
⋯
H distance (~2.3e2.9 Å) and
⋯
HeC angles in the range ~110e170ꢁ. Hydrogen bonds are
3ce4e interactions with almost linear geometry [48]. In complex
10, it is particularly interesting that packing effects, steric and
electronic effects of dithiocarbamate and triphenylphosphine li-
gands and square planar Ni(II), d8 force the ortho proton of a
phenyl ring in triphenylphosphine ligand to be close proximity to
an axial position around the nickel atom thus creating weak
anagostic interaction [Ni/H ¼ 2.967 Å and <CeH/Ni ¼ 119ꢁ]
(Fig. 3). The complexes with anagostic interactions are believed
to act as catalysts. S1 of CS2 and S3 of thiocyanate form inter-
molecular CeH/S bond with H22 and H4 of phenyl rings,
respectively (Fig. 4). S1 and S2 of CS2 group are involved in the
formation of intramolecular CeH/S bonds with H10A and H2A
of methylene groups, respectively (Table 3, Fig. 5).
A weak CeH/Ni intramolecular anagostic interaction is also
observed in complex 12 (Fig. 6, Table 4). Recently, Tiekink and
Zukerman-Schpector have reported [16] that CeH⋯p (chelate ring)
interactions play an important role in stabilizing crystal structures
Scheme 3. The parameters for CeH
⋯
Cg (chelate) interactions: d1 ¼ 2.4e3.6 Å,
a
< 20ꢁ
and
b
¼ 110e180ꢁ.
of metal bis(1,1-dithiolates). CeH
the formation of 1D, 2D and 3D supramolecular assemblies
(Scheme 3). The CeH Cg (chelate) interaction parameters are
defined as d1, the distance between the ring centroid of the MS2C
ring and the H atom (2.4e3.6 Å), , angle between the perpendic-
⋯Cg (chelate) interactions lead to
(Centroid of C13eC18 phenyl ring) distance of 3.016 Å which gives
rise to chain structure in solid state (Fig. 8). Intermolecular CeH/Cl
(H10/Cl1 ¼ 2.897 Å) interaction is also observed (Fig. 9). S1 and S2
⋯
a
involve in the formation of intramolecular CeH⋯S interactions
ular to the MS2C ring (a b, the CeH⋯Cg angle
< 20ꢁ) and d1, and
[C20eH20A
thiocyanate (S3) forms intermolecular CeH
and H23B [C20eH20B/S3 ¼ 2.853 and C23eH23/S3 ¼ 2.801 Å]
⋯
S1 ¼ 2.575 and C27eH27A$$$S2 ¼ 2.674 Å]. Sulfur of
(
b
¼ 110e180ꢁ). In complex 12, NiS2C ring involves the CeH⋯p
⋯
S bonds with H20B
(chelate) interaction. The dimension of CeH⋯p (chelate) interac-
tion is
a
¼ 16ꢁ,
b
¼ 149ꢁ and d ¼ 3.605 Å (Fig. 7). Complex 12 is
(Fig. 10).
stabilized by CeH⋯p intermolecular interaction with H16⋯Cg2
Fig. 6. Intramolecular CeH⋯Ni anagostic interaction in complex 12.
Fig. 7. Intermolecular CeH⋯p (chelate) interaction in complex 12.
Table 4
Geometric details of hydrogen bonding (Å,º) in complex 12.
Interactions
DeH
H
⋯A
D
⋯A
DeH⋯A
C2eH2/Nia
0.93
0.93
0.93
0.93
0.93
0.97
0.97
0.97
2.995
3.605
3.016
2.897
2.801
2.853
2.674
2.575
3.538(3)
4.428(4)
3.906(4)
3.664(5)
3.728(5)
3.792(4)
3.069(4)
3.104(4)
118.82
148.96
160.79
140.45
175.30
163.19
104.81
114.36
C25eH25
C16eH16
⋯
⋯
Cg1b [C19,S2,S1,Ni]
Cg2C [C13eC18]
C10eH10/Cl1d
C23eH23/S3d
C20eH20B/S3d
C27eH27A$$$S2e
C20eH20A⋯
S1e
a
Intramolecular anagostic interaction.
CeH/p (chelate) interaction.
b
c
Intermolecular CeH⋯p interaction.
d
e
Intermolecular CeH
⋯
Cl and CeH
⋯S interactions.
Intramolecular CeH
⋯S interaction.
Fig. 8. Molecular chain through intermolecular CeH⋯p interaction in complex 12.

392
E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
Fig. 9. Intermolecular CeH⋯Cl interaction in complex 12.
3.4.2. Theoretical calculations
All calculations were performed with GAUSSIAN09 program
package [49] with the aid of the Gauss View visualization program.
The optimized structure of complexes 10 and 12 was given in
Figs. 11 and 12. The theoretical and experimental values for the
selected bond lengths and angles are given in Table 5. The param-
eters of interest are NieS, NieN, NieP, CeS and CeN bond distances
and associated angles. Comparison of the experimental bond pa-
rameters with the calculated values of both the complexes shows
that the bond length difference is in the range 0.001e0.072 Å for
NieN, CeS, CeN (thioureide), CeN (NCS) and CeS (thiocyanate)
and the bond angle difference is in the range for 0.03e0.75ꢁ for
NeNieP, NeNieS1 and CeS1eNi. The anagostic interaction
observed in experimental structural analysis is not found in opti-
mized structures [Calculated values: CeH/Ni ¼ 3.2014 and
3.1939 Å for 10 and 12, respectively]. This indicates that the packing
effects in solid state force the ortho proton of phenyl ring in tri-
phenylphosphine to create anagostic interaction. These differences
between experimental and theoretical values are due to the
following reasons; all of the calculated data are for the molecule in
Fig. 11. Optimized structure of complex 10.
gas phase and these are no inter- and intramolecular interactions
while the experimental data are for the molecule in solid state and
there are molecular interactions among them.
The NieS distances [NieS1 ¼ 2.2291(9), NieS2 ¼ 2.1634(9) for
10, NieS1 ¼ 2.1702(10), NieS2 ¼ 2.2245(9) for 12] are asymmetric
and NieP distance [2.1871(9) for 10 and 2.1903(8) for 12] is short in
the structures determined by X-ray crystallography. But in the
optimized structure the NieS distances are symmetric and the
NieP distance is longer [ca. 0.32]. These differences are also
observed in related bond angles. These reveal that the trans influ-
ence and back bonding interaction between Ni and P are absent in
gaseous state.
3.4.2.1. HOMO-LUMO. Frontier molecular orbital pictures of the
optimized of the structure of the complexes 10 and 12 are shown in
Fig. 13.The HOMO is located fully on sulfur and partially on nitrogen
of NCS─ and the LUMO is more focused on the Ni (central metal
atom) and phosphorous partially on C and N of NCS2 group.
3.4.2.2. MEP. Molecular electrostatic potential (MEP) surface
Fig. 10. Intra- and intermolecular CeH
⋯
S interactions in complex 12.
Fig. 12. Optimized structure of complex 12.

E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
393
Table 5
Comparison of selected optimized geometrical parameters of complexes 10 and 12 with experimental XRD parameters.
10
12
Bond distances (Å)
XRD exptl.
Calcd
1.8991
differences
Bond distances (Å)
XRD exptl.
Calcd
1.8975
differences
Ni1eN2
Ni1eS2
Ni1eP1
Ni1eS1
S2eC1
1.866(3)
2.1634(9)
2.1871(9)
2.2291(9)
1.726(3)
1.715(3)
1.617(4)
1.150(4)
1.312(4)
0.0331
0.2146
0.324
0.1678
0.0695
0.0671
0.0574
0.0183
0.0014
Ni1eN2
Ni1eS1
Ni1eP1
Ni1eS2
S1eC19
S2eC19
S3eC36
C19eN1
C36eN2
1.860(3)
2.1702(10)
2.1903(8)
2.2245(9)
1.722(3)
1.708(3)
1.620(4)
1.318(4)
1.150(4)
0.0375
0.2112
0.3176
0.176
2.3780
2.5111
2.3969
1.7955
1.7821
1.6744
1.1683
1.3134
2.3814
2.5079
2.4005
1.7940
1.7796
1.6738
1.3158
1.1685
0.072
S1eC1
0.0716
0.0538
0.0022
0.0185
S3eC36
C36eN2
N1eC1
Bond angles (ꢁ)
Bond angles (ꢁ)
N2eNi1eS2
N2eNi1eP1
S2eNi1eP1
N2eNi1eS1
S2eNi1eS1
P1eNi1eS1
C1eS2eNi1
C1eS1eNi1
N2eC36eS3
N1eC1eS1
N1eC1eS2
S1eC1eS2
174.86(8)
88.99(8)
95.95(3)
95.99(8)
79.11(3)
174.77(4)
86.67(11)
84.87(11)
178.3(3)
125.6(2)
125.6(3)
108.82(18)
172.3(3)
172.80
89.49
97.60
95.96
76.97
174.41
85.49
85.21
179.01
123.94
123.74
112.31
174.53
2.06
0.5
N2eNi1eS1
N2eNi1eP1
S1eNi1eP1
N2eNi1eS2
S1eNi1eS2
P1eNi1eS2
C19eS1eNi1
C19eS2eNi1
N1eC19eS2
N1eC19eS1
S2eC19eS1
N2eC36eS3
C36eN2eNi1
174.62(8)
88.89(8)
96.28(3)
95.98(8)
78.89(3)
174.96(4)
86.66(12)
85.29(11)
125.8(2)
125.2(3)
109.00(18)
179.0(3)
171.0(3)
172.66
89.64
97.62
95.90
76.84
174.40
85.44
85.18
123.87
123.60
112.52
179.01
174.62
1.96
0.75
1.34
0.08
2.05
0.56
1.22
0.11
1.93
1.6
1.65
0.03
2.14
0.36
1.18
0.34
0.71
1.66
1.86
3.49
2.23
3.52
0.01
3.62
C36eN2eNi1
Fig. 13. The frontier molecular orbital (HOMO-LUMO) pictures of the optimized structures of 10 (a and c) and 12(b and d).

394
E. Sathiyaraj et al. / Journal of Molecular Structure 1119 (2016) 385e395
12 revealed the existence of intramolecular anagostic CeH⋯Ni
interactions in both the complexes. This type of transition metal
complexes with anagostic interaction may play important role in
CeH activation in synthetic organic chemistry. Anagostic interac-
tion is not observed in the optimized structures. This indicates that
the packing effect is an important force to create the anagostic
interaction. This study will be helpful in designing functionalized
dithiocarbamate ligands containing a variety of substituents that
may exhibit various interactions for their possible applications as
novel functional materials.
Acknowledgment
The authors are thankful to Dr. SP. Meenakshisundaram, pro-
fessor and former Head, Department of Chemistry, Annamalai
University, Annamalainagar-608 002 for providing GAUSS IAN09
program.
Supplementary material
CCDC numbers 1431934 and 1431813 contain the supplemen-
tary crystallographic data for complexes 10 and 12, respectively.
These data can be obtained free of charge from the Cambridge
Crystallographic Data Center via www.ccdc.cam.ac.uk/data_
request/cif.
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