Effect of N-Bound Organic Moiety in Dithiocarbamate (R2NCS-2) and trans Influence of Triphenylphosphine on NiS2PN Chromophore

Article abstract of DOI:10.1080/10426507.2014.976337

Three square planar Ni(II) complexes of the composition [Ni(bzcprdtc)₂](1), [Ni(bzcprdtc)(NCS)(PPh₃)](2) and [Ni(bzcprdtc)(PPh₃)₂]ClO₄ (3)[(where bzcprdtc = N-benzyl-N-cyclopropyl-dithiocarbamate)] ha

Full text of DOI:10.1080/10426507.2014.976337

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EFFECT OF N-BOUND ORGANIC MOIETY IN
-
DITHIOCARBAMATE (RNCS2 ) AND trans INFLUENCE OF
TRIPHENYLPHOSPHINE ON NiS2PN CHROMOPHORE
Ethiraj Sathiyaraja, Panneerselvam Valarmathia, Subbiah Thirumarana, Samuele Ciattinib,
Vivek K. Guptac & Rajni Kantc
a Department of Chemistry, Annamalai University, Annamalainagar 608 002, India
b Centro di Cristallografia Strutturale, Polo Scientifio di Sesto Fiorentino, Via della
Lastruccia N°3, 50019 Sesto Fiorentino, Firenze, Italy
c X-Ray Crystallography Laboratory, Post-Graduate Department of Physics & Electronics,
University of Jammu, Jammu Tawi 180 006, India
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Accepted author version posted online: 03 Nov 2014.
To cite this article: Ethiraj Sathiyaraj, Panneerselvam Valarmathi, Subbiah Thirumaran, Samuele Ciattini, Vivek K.
-
Gupta & Rajni Kant (2014): EFFECT OF N-BOUND ORGANIC MOIETY IN DITHIOCARBAMATE (RNCS2 ) AND trans INFLUENCE
OF TRIPHENYLPHOSPHINE ON NiS2PN CHROMOPHORE, Phosphorus, Sulfur, and Silicon and the Related Elements, DOI:
10.1080/10426507.2014.976337
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–
EFFECT OF N-BOUND ORGANIC MOIETY IN DITHIOCARBAMATE (RNCS2 ) AND
trans INFLUENCE OF TRIPHENYLPHOSPHINE ON NiS2PN CHROMOPHORE
Ethiraj Sathiyaraj1, Panneerselvam Valarmathi1, Subbiah Thirumaran1*, Samuele Ciattini2,
Vivek K. Gupta3 and Rajni Kant3
1Department of Chemistry, Annamalai University, Annamalainagar 608 002, India
2Centro di Cristallografia Strutturale, Polo Scientifio di Sesto Fiorentino, Via della Lastruccia
N3, 50019 Sesto Fiorentino, Firenze, Italy.
3X-Ray Crystallography Laboratory, Post-Graduate Department of Physics & Electronics,
University of Jammu, Jammu Tawi 180 006, India
E-mail: sthirumaran@yahoo.com
Abstract
Three square planar Ni(II) complexes of the composition [Ni(bzcprdtc)2](1),
[Ni(bzcprdtc)(NCS)(PPh3)](2)
and
[Ni(bzcprdtc)(PPh3)2]ClO4
(3)[(where
bzcprdtc=N-benzyl-N-cyclopropyl-dithiocarbamate)] have been synthesized and
1
characterized by H and 13C NMR, UV-Vis and FT-IR spectroscopy. 13C NMR spectra show
interesting differences between the N13CS2 carbon signals of the parent complex 1 and
heteroleptic complex 2. The N13CS2 carbon signal for 2 is observed at 209.3 ppm with an upfield
shift of about 3.5 ppm compared with that found for 1 (212.8 ppm). The observed shielding in 2
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indicates the effect of PPh3 on the mesomeric drift of electron density toward nickel through the
thioureide C-N bond of [Ni(dtc)(NCS)(PPh3)]. Single crystal X-ray analysis of 2 and
[Ni(dbpdtc)(NCS)(PPh3)](4) (dbpdtc
=
benzyl(4-(benzylamino)phenyl)dithiocarbamate)
confirmed distorted square planar arrangement in the vicinity of the nickel atom with a S2NP
donor set. Comparative analysis of bond parameters of [Ni(dtc)2] and [Ni(dtc)(NCS)(PPh3)] has
also been studied.
Keywords: dithiocarbamate; Nickel(II); thiocyanate; single-crystal X-ray analysis
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1. Introduction
The physicochemical properties of dithiocarbamate compounds allow for wide applications in
different areas. These compounds were found to be useful as accelerators of vulcanization1,
fungicides2 and pesticides3. Several thousands of transition metal complexes with the
dithiocarbamate moiety have been prepared and reported to date and some of them are very
promising from the biological activity point of view. The PtII complex of composition
[Pt(esdtc)(Py)Cl] [esdtc = ethylsarcosinedithiocarbamate and Py = pyridine] is highly cytotoxic
against several human cancer cell lines and more over, this substance was not found to be
nephrotoxic in contrast to the cis platin4. Attention has been focused on nickel dithiocarbmate
complexes for the large variety of the reactions in which they are involved as catalysts and are
used for the preparation of semiconducting metal sulfide thin film by single source MOCVD
techniques5,6. A number of bis(dithiocarbamato)nickel(II), [Ni(dtc)2] and [Ni(dtc)(NCS)(PPh3)]
complexes have been synthesized, several of them have been characterized by single crystal X-
ray diffraction7-13. The Ni-S bond distances are in the range 2.19-2.21Å and are symmetric with
∆(Ni-S), defined as Ni-Slong – Ni-Sshort , being usually less than 0.02Å for all the [Ni(dtc)2]
complexes except [Ni(dbpdtc)2]8 which is reported from our laboratory. In all the
[Ni(dtc)(PPh3)(NCS)] complexes, the Ni-S bond trans to PPh3 is longer than the other Ni-S bond.
The aim of the present work is to study the trans effect of triphenylphosphine in
[Ni(dbpdtc)(NCS)(PPh3)] and to compare the structural parameters of [Ni(dtc)2] and
[Ni(dtc)(NCS)(PPh3)]. In this paper, we report synthesis and spectral studies on
[Ni(bzcprdtc)2](1), [Ni(bzcprdtc)(NCS)(PPh3)](2) and [Ni(bzcprdtc)(PPh3)]ClO4(3).
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In addition to this, single crystal X-ray structural analysis of [Ni(bzcprdtc)(NCS)(PPh3)] (2)
and [Ni(dbpdtc)(NCS)(PPh3)] (4) are also reported.
2. RESULTS AND DISSCUSION
Complexes 1-3 were prepared according to the synthetic procedure shown in Scheme 1.
Benzaldehyde was condensed with cyclopropylamine to form the imine. Sodium borohydride
reduction of imine in methanol-dichloromethane yielded secondary amine. Complex 1 was
prepared from secondary amine in ethanol by reaction with CS2 and NiCl2.6H2O. Complex 2 was
prepared by refluxing 1, NiCl2.6H2O, NH4SCN and PPh3 in acetonitrile-methanol and the
reaction under reflux (3 h) between 1, NiCl2.6H2O, NaClO4 and PPh3 yielded 3.
[Insert Scheme 1]
2.1 FT-IR spectral studies
Important bands in the IR spectra of dithiocarbamate complexes are due to the C-N and C-S
stretching modes. In the FT-IR spectra of the complexes 1-3, the thioureide C–N bands are
observed at 1472, 1497 and 1478 cm-1, respectively. These bands indicate that the C-N bond
order is intermediate between a single bond (1350-1250 cm-1) and double bond (1690-1650 cm-1)
14
(Scheme 2) . The C–N (thioureide) band of heteroleptic complexes observed at higher wave
number compared with parent homoleptic complex 1 is due to the mesomeric drift of electron
density from the bzcprdtc ligand towards nickel, increasing the contribution of polar thioureide.
The C-S stretching vibrations are observed around 1025 cm-1 without any splitting, supporting
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the bidentate coordination of the dithiocarbamate moiety 15. The observed stretching frequency at
2084 cm-1 for 2 is assigned to the N-coordinated thiocyanate. The intense signal observed at
1090cm-1 for 3 is attributed to ClO4.
[Insert Scheme 2]
1
2.2. H NMR spectral studies
In the complex 1, two singlets observed at 0.89 and 4.79 ppm are due to the methylene protons
of the cyclopropyl and benzyl groups, respectively. The methyne proton of cyclopropyl group
shows a broad signal at 2.61 ppm. The signals of methylene protons in the ring are observed in
the upfield region compared to the signals of methylene protons outside the ring (methylene
protons of benzyl group). The chemical shifts of methyne proton of cyclopropyl and methylene
protons of benzyl group are observed in the downfield region due to the release of electron
density on the nitrogen of NR2 groups, forcing high electron density towards the sulfur or metal
via the thioureide -system. The aliphatic protons of dithiocarbamate in 2 and 3 are observed as
C
N
bond rotation as observed in phosphine complexes. In
broad signals. This is due to the
all the complexes, the aromatic protons resonate in the region 7.16-7.80 ppm.
2.3. 13C NMR spectral studies
The chemical shift of the thioureide carbon atoms (N13CS2) are observed at 212.8 and 209.3 ppm
for the complexes 1 and 2 respectively. This indicates the partial double bond character of C-N
(thioureide) and C-S bonds. The N13CS2 chemical shift of dithiocarbamate is affected by the
coordination of the PPh3 to the nickel atom. The N13CS2 carbon site of the 2 is shielded by 3.5
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ppm compared to the parent 1. The presence of a triphenylphosphine (-acceptor) in 2 increases
the mesomeric drift of electron density from the dithiocarbamate moiety towards the metal
atom16. This causes an increase in N-C partial double bond character of dithiocarbamate in 2.
2.4. Electronic spectral studies
The electronic spectra of the complexes [Ni(bzcprdtc)2], [Ni(bzcprdtc)(NCS)(PPh3)] and
[Ni(bzcprdtc)(PPh3)2]ClO4were recorded in chloroform. In the case of 1, two d-d transition
17
2
2
2
2 2
bonds are observed at 624 (dxy  dx –y ) and 458 nm
(dz  dx –y
)
transitions,
respectively and are suggestive of the square planar geometry around Ni(II) metal ion. The bands
observed at 490 and 455 nm for the complexes 2 and 3 respectively are due to the d-d transitions.
2 /
2 2
These bands are assigned to dz dxy dx –y transitions. In all the complexes 1-3, bands observed
in the UV region are due to the intraligand -* transitions, mainly associated with the
intramolecular intraligand transitions corresponding to -* transitions of the N-C=S and S-C=S
groups and n–* transition located on the sulfur atom18.
2.5 . Single crystal X-ray structural analysis
The [Ni(bzcprdtc)(NCS)(PPh3)] (2) and [Ni(dbpdtc)(NCS)(PPh3)] (4) complexes crystalized
in triclinic and monoclinic systems with the space groups Pī and Cc, respectively. The crystal
data and refinement parameters are given in the Table 1. Selected bond distances and angles are
listed in Table 2 and 3. The ORTEP diagrams of 2 and 4 are shown in Figures 1 and 2,
respectively. The central NiII ion of the both complexes 2 and 4 are tetracoordinated by PPh3,
isothiocyanate and bidentate coordinated dithiocarbamate anion. The atoms of NiS2NP
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chromophore arranged in the distorted square planar geometry around the metal centre. The
distortion from the normal geometry arises from the bidentate ligand (S1-Ni-S2 of 78.97(3)° and
78.90(5)° for the 2 and 4, respectively). Which causes the trans S-Ni-N and S-Ni-P angles to be
between 172.08° and178.3°, smaller than the expected value of 180°. The other angles [N2-Ni-
P1=91.96 (8)°, S1-Ni-P1= 95.56 (3)° for 2 and N3-Ni-P1=93.70 (15)°, S1-Ni-P1=94.22(5)° for
4)] are slightly deviated from the ideal cis angle 90°. Selected bond lengths and angles are
presented in Tables 2 and 3
[Insert Table 1]
[Insert Figure 1]
[Insert Figure 2]
The structure adopted by these complexes are characterized using 4 descriptor for four
coordination ions suggested by Yang et.al19. The distortion index is defined as 4 = 360-
(+ß)/141. The 4 values for perfect, see saw structure, trigonal pyramid and tetrahedral are 0.00,
0.07-0.64, 0.85 and 1.00 respectively. 4 values for the complexes 2 and 4 are 0.102 and 0.106
respectively, which indicate that the coordination geometry of both the complexes is a seesaw
structure. In both the complexes, the dithiocarbamate ligands are bidentate giving four membered
chelate rings [NiS2C]. Their planar geometry is supported by the corresponding torsion angles
which are close to 0 and 180°. The C-S bond lengths in complexes 2 and 4
(ca.1.72Å) are
characteristic of the partial double bonds (typical bond lengths: 1.81Å for C-S and 1.69Å for
C=S). The C-N bond distances in both the complexes are shorter than the C=N bond length (ca
1.35Å). This behavior indicates that the electron density is delocalized over the NCS2 moiety.
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The Ni-N distances 1.866(2)Å and 1.856(5)Å for 2 and 4, respectively, are significantly sh rt
which sh ws the effective nding etween the nic el at and NC . The N-C-S bond angle in
thiocyanate is 178.3 and 178.9° for 2 and 4, respectively and is almost linear. Ni-P distances are
2.1854(8)Å and 2.2032(14)Å for complexes 2 and 4. These short Ni-P distances indicate a better
bonding and back bonding interaction between Ni and P in [Ni(dtc)(NCS)(PPh3)] complexes20.
[Insert Table 2]
[Insert Table 3]
2.6.
Comparative analysis of Ni–S, C–N and C–S distances and related angles in
Ni(dtc)2 and [Ni(dtc)(NCS)(PPh3)]
Of particular interest with respect to the dithiocarbamate- metal bonding are the M–S, C–S and
C–N distances and the related angles. A comparison of the bond parameters is given Table 4.
Table 4 shows that the Ni–S bond distances are symmetric with (Ni–S), defined as Ni–Slong
Ni–Sshort, being usually less than 0.02Å for all the [Ni(dtc)2] complexes except
[Ni(dbpdtc)2]. For all the [Ni(dtc)(NCS)(PPh3)] complexes except
–
[Ni(dbpdtc)(NCS)(pph3)], the differences in Ni–S bond distances [(Ni–S)] are about 0.036-
0.056 Å indicating the significant asymmetry in Ni–S bonds. This observed difference in Ni–S
distances is attributed to the difference in the trans influencing properties of PPh3 and
NCS–. PPh3 being a good -acceptor has greater influence and hence the Ni–S bond trans to
PPh3 is longer than the other Ni–S bond. The Ni–S bond distances are slightly asymmetric in
[Ni(dbpdtc)2] ((Ni–S) = 0.023 Å) and symmetric in [Ni(dbpdtc)(NCS)(PPh3)] ((Ni–S) = 0.018
Å). This may be due to the resonance effect and steric bulk of the dithiocarbamate ligand.
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The Ni–S–C and S–Ni–S bond angles are also slightly affected by the  back bonding effect of
the triphenylphosphine in [Ni(dtc)(NCS)(PPh3)]. No significant changes in C–N and C–S bond
lengths and S–C–S and N–C–S bond angles are observed. This study confirms that Ni-S bonds
are affected by the trans effect of triphenylphosphine and N-bound organic moiety of
dithiocarbamate ligand.
[Insert Table 4]
3. Conclusions
Three new nickel(II) complexes have been prepared and characterized using IR, NMR and UV-
Vis spectroscopy. The spectroscopic data reveal that all the compounds have square planar
geometry. Single crystal X-ray structural studies on 2 and 4 show that the geometry of both
complexes are not of the perfect square planar, because of the small bite angle (S-Ni-S)
associated with the dithiocarbamate ligands. Comparative analysis is of bond parameters of
[Ni(dtc)2] and [Ni(dtc)(PPh3)(NCS)] complexes reveals the trans effect triphenylphosphine and
the effect of N-bound organic moiety in dithiocarbamate ligands on bond parameters of nickel
complexes.
4. Experimental
4.1. Chemicals, Instrumentations
All reagents and solvents were pure and used as purchased Merck, Sigma, Spectrochem) without
further purifications. Melting points were determined using an electro thermal IA 9300 apparatus
and were not corrected. Elemental analysis (C,H,N) were performed on Perkin Elmer 2400
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series(II) CHN analyzer. FT-IR spectra (600-4000cm-1 region; KBr ) was recorded on Thermo
1
Nicolet Avatar 330. H and 13C NMR spectra of CDCl3 solution were recorded on a Bruker
400/100 MHz. UV-Vis spectra were obtained on a Shimadzu UV-1650 PC spectrometer.
4.2. X-ray crystallography
Single Crystal x-ray diffraction data for 2 and 4 were rec rded n an ‘Xcali ur, apphire 3’
diffractometer equipped with graphite monochromated MoK radiation ( = 0.71069Å) at ambient
temperature. The structure was solved by direct methods SHELXS-9721 and refined on F2 with
full matrix least-squares method in SHELXL-9722. Non-hydrogen atoms were refined
anisotropically and the hydrogen atoms were refined isotropically.
4.3. Synthesis of metal complexes
4.3.1. Preparation of N-benzyl-N-cyclopropylamine
Cyclopropylamine (4.6 mmol, 0.5 mL) and benzaldehyde (5.1 mmol, 0.4 mL) were dissolved in
methanol (40 mL) and the solution was stirred for 2 h at room temperature. The solvent was
removed by evaporation. The resulting colourless oil was dissolved in methanol-
dichloromethane solvent mixture (1:1, 20 mL) and sodium borohydride (13.8 mmol, 0.5 g) was
added slowly and stirred for 2 h at 5°C. The reaction mixture was stirred at room
temperature for 20 h. After evaporation of the solvent, the resulting viscous liquid was washed
with water and dichloromethane was added in order to extract the product. Evaporation of the
organic layer gave N-benzyl-N-cyclopropylamine as pale yellow oil.
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4.3.2. Preparation of 1
An ethanolic solution of N-benzyl-N-cyclopropylamine (4mmol, 0.64g) was treated with carbon
disulfide (4mmol, 0.3mL) and stirred for 30min at 5°C; yellow dithiocarbamic acid was
obtained. NiCl2.6H2O was dissolved in 50ml of water and was added to the solution drop wise
leading to the formation of olive green precipitate. The precipitate was then filtered off, washed
with distilled water and then dried. (Scheme 1). Yield: 68%; Dec. 186-188°C; Anal.calc. for
C,54.04 H,5.67 N,5.25 (MW= 532.06); found C,53.72 H,5.54 N,5.17. IR (KBr, cm–1):  =
1472 (C–N), 1020 (C–S). UV-Vis (CHCl3, nm):  = 624, 458, 419, 397, 339, 276. 1H NMR (400
MHz, CDCl3, ppm):  = 4.79 (s, CH2), 2.61 [br, CH (cyclopropyl)], 0.88 [br, CH2 (cyclopropyl)],
13
7.33 (br, aromatic protons). C NMR (100 MHz, CDCl3, ppm):  = 53.1 (N–CH2–C6H5), 31.8
[CH (cyclopropyl)], 7.8 [CH2 (cyclopropyl)], 127.9, 128.1, 128.4, 134.9 (phenyl ring carbons),
212.8 (NCS2).
4.3.3. Preparation of 2
A mixture of [Ni(bzcprdtc)2] (0.533g, 1.0 mmol), PPh3 (0.52g, 2mmol), NiCl2.6H2O (0.327g, 1.0
mmol) and NH4SCN (0.152g, 2.0 mmol) was refluxed in acetonitrile-methanol solvent mixture
(1:1, 50 mL) for 3 h. The purple red solution obtained was filtered and left for evaporation.
After 5 d, a purple red solid separated out, which was recrystallized from chloroform (Scheme
1). Suitable crystals for X-ray structural analysis were obtained by repeated recrystallization
from dichlromethane-methanol solvent mixture. Yield:63% ; Dec. 98-100°C; Anal.calc.for
C,59.91 H,4.53 N,4.66 (MW=601.41); found C,59.68 H,4.45 N,4.58. IR (KBr, cm–1):  = 2084
1
(NCS), 1478 (C–N), 1025 (C–S). UV-Vis (CHCl3, nm):  = 490, 451,397,331, 261. H NMR (400
MHz, CDCl3, ppm):  = 4.45–4.78 (two broad signals overlapped to appear as a three signals, CH2),
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2.50, 2.67 [two broad signals, CH (cyclopropyl)], 0.73-0.90 [m, CH2 (cyclopropyl)], 7.16-7.73
(aromatic protons). 13C NMR (100 MHz, CDCl3, ppm):  = 53.1, 53.4 (N–CH2–C6H5), 31.8 [CH
(cyclopropyl)], 7.4, 7.8 [CH2 (cyclopropyl)], 127.9, 128.0, 128.1, 128.2, 128.4, 128.8, 128.9,
129.0, 129.1, 131.1, 132.0, 134.1, 134.2, 135.0 (phenyl ring carbons), 209.3 (NCS2).
4.3.4 Preparation of 3
A mixture of [Ni(bzcprdtc)2] (0.533g, 1.0 mmol), PPh3 (0.52g, 2mmol), NiCl2.6H2O
(0.327g,1.0mmol) and NaClO4 (0.152g, 2.0 mmol) was refluxed in chloroform- methanol solvent
mixture (3;2 50 mL) for 3 h. The purple red solution obtained was filtered and left for
evaporation. After 2 d, a purple red solid separated out, which was recrystallized from
chloroform (Scheme 1).
Yield: 63%;
Dec. 96-98°C; Anal. Calc .for C,62.66 H,4.93
N,1.52 (MW=920.00); found C,62.42 H,4.85 N,1.48. IR (KBr, cm–1):  = 1090 (ClO4), 1478 (C–
N), 1025 (C–S). UV-Vis (CHCl3, nm):  = 455, 397, 331, 295, 270. 1H NMR (400 MHz, CDCl3, ppm): 
= 4.63–4.69 (broad doublet, CH2), 2.55, 2.60 [broad doublet, CH (cyclopropyl)], 0.82, 0.88 [br,
13
CH2 (cyclopropyl)], 7.19-7.81 (aromatic protons). C NMR (100 MHz, CDCl3, ppm):  =53.1,
53.4 (N–CH2–C6H5), 31.9, 32.0[CH (cyclopropyl)], 7.4, 7.6[CH2 (cyclopropyl)], 128.0, 128.5,
128.6, 128.7, 129.0, 129.9, 130.5, 130.7, 131.6, 131.9, 132.0, 132.2, 132.3, 132.9, 133.0, 133.1,
133.3, 133.8, 133.9, 135.3 (phenyl ring carbons).
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4.3.5 Preparation of 4
Complex 4 was prepared by the method reported in the literature [8]. Purple colour crystals were
obtained from the slow evaporation of chloroform-ethanol (2:1) solution of 4.
5. Supplementary materials
CCDC 1013960 and 1013879 contain the supplementary crystallographic data for the complexes
2 and 4. Copies of the data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
Acknowledgements
Dr. S. Thirumaran is thankful to University Grants Commission (UGC), India (F. No. 42-
341/2013 (SR)) for providing fund for this research study. E. Sathiyaraj gratefully acknowledges
the University Grants Commission (UGC), India, for the award of Basic Sciences Research
(BSR)-Special Assistant Programme (SAP) Fellowship.
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13. Sheldrick, G.M. SHELXL-97, University of Gottingen, Gottingen, Germany 1997.
14. Oliveira, M. R. L. De Bellis, V. M. Trans. Metal Chem. 1999, 24, 127-130.
15. Bonati, F.; Ugo, R. J. organomet. Chem. 1967, 10, 257-268.
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16. Fackler, Jr. J.P.; Lin, I. J. B.; Andrews, J. Inorg. Chem. 1977, 16, 450.
17. Jorgensen, C. K. J. Inorg. Nucl. Chem. 1962, 24, 1571-1581.
18. Manav, N.; Mishra, A.K.; Kaushik, N.K. Spectrochim. Acta Part A, 2006, 65, 32-35.
19. Yang, L.; Powell, D.R.; Houser, R.P. Dalton Trans. 2007, 955-964.
20. Srinivasan, N.; Sathyaselvabala, V.; Kuppulakshmy, K.; Valarmathi, P.; Thirumaran, S.
Monatsh Chem. 2009, 140, 1431-1436.
21. Srinivasan, S.; Ramalingam, K.; Rizzoli, C. Polyhedron 2012, 33, 60-66.
22. Sheldrick, G. M. Acta Cryst. 2008, A64, 112-122.
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Scheme 1 Preparation of complexes
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Scheme 2
Scheme 2 The resonance structures of dtc ligands
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Figure 1: ORTEP diagram of 2
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Figure 2 ORTEP diagram of 4
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Table 1 Crystal Structure and Data Refinement Parameters for 2 and 4
Compound
2
4
Empirical formula
C30H27N2NiPS3
601.40
C40H34N3NiPS3
742.56
Formula Weight
Crystal system / Space group
Triclinic / Pī
10.3295(5)
11.2565(6)
13.9232(7)
100.845 (4)
Monoclinic / Cc
18.167(5)
11.948(5)
20.977(5)
90.000(5)
a/Å
b/Å
c/Å
/
101.311(4)
109.455(4)
1439.47(13)
2
123.590(5)
90.000(5)
3793(2)
4
/
/
V/Å3
Z
Dcalc (g/cm3)
 (cm–1)
Crystal size (mm)
Color / Shape
1.388
1.300
0.969
0.750
0.35 0.25 0.20
0.25  0.20  0.20
Brown / prismatic
Brown/ block
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Temp (K)
100(2)
293(2)
Theta range for collections
Reflections collected
Independent reflections
Data / restraints / parameters
Goodness of fit on F2
Final R indicates I> 2(I)
R indicates (all data)
4.23-29.47
6541
3.41-32.32
8190
4724
4278
6541/0/ 442
1.135
8190/2/ 438
0.854
4724
4278
0.0431, 0.0908
0.478, -0.411
0.0546, 0.1419
0.556,-0.547
Largest difference peak / hole
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Table 2 Selected bond distances (Å) and angles () for 2
Bond distance (Å)
Ni–S1
Bond angle ()
N2–Ni–S1
2.1742(7)
2.1854(8)
2.6159(8)
1.866(2)
1.314(3)
1.152(3)
1.720(3)
1.710(3)
1.625(3)
172.47(8)
91.96(8)
95.56(3)
93.49(8)
78.97(3)
173.13(3)
178.3(3)
108.96(15)
86.53(9)
85.47(10)
Ni–P1
N2–Ni–P1
S1–Ni–P1
N2–Ni–S2
S1–Ni–S2
P1–Ni–S2
N2–C12–S3
S2–C1–S1
C1–S1–Ni
C1–S2–Ni
Ni–S2
Ni–N2
N1–C1
N2–C12
S1–C1
S2–C1
S3–C12
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Table 3 Selected bond distances (Å) and angles () for 4
Bond distances (Å)
C1–N1
Bond angles ()
126.1(4)
1.285(6)
1.721(5)
1.739(5)
1.458(7)
1.391(9)
1.474(6)
1.425(11)
1.160(6)
1.616(5)
1.822(5)
1.821(5)
1.818(5)
2.2032(14)
2.1914(15)
2.2095(15)
1.856(5)
N1–C1–S2
N1–C1–S1
S2–C1–S1
C1–S2
126.0(4)
C1–S1
107.8(3)
C2–N1
C5–N2
C8–N1
C15–N2
C22–N3
C22–S3
C23–P1
C29–P1
C35–P1
P1–Ni1
S1–Ni1
S2–Ni1
N3–Ni1
N3–C22–S3
C1–N1–C2
C1–N1–C8
C2–N1–C8
C5–N2–C15
C35–P1–C23
C35–P1–C29
C23–P1–C29
C35–P1–Ni1
C23–P1–Ni1
C29–P1–Ni1
C1–S1– Ni1
C1–S2–Ni1
C22–N3–Ni1
N3–Ni1–S1
N3–Ni1–S2
S1–Ni1–S2
N3–Ni1–P1
S1–Ni1–P1
S2–Ni1–P1
178.9(4)
117.5(4)
123.5(4)
119.0(4)
124.4(7)
105.5(2)
107.3(2)
107.7(2)
113.55(16)
111.75(16)
110.74(17)
86.64(17)
86.50(18)
175.7(4)
172.08(15)
93.19(15)
78.90(5)
93.70(15)
94.22(5)
173.04(6)
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Table 4 Comparison of bond distances (Å) and angles ()
Ref
Complex
[Ni(bfdtc)2]
Ni–S1
Ni–S2
C–S
S–C–S
S.No
C–N
S–Ni–S
Ni–S–C
N–C–S
1.
2
2.1914(14)
2.1841(8)
2.1831(10)
2.2073(13)
2.2202(10)
2.2061(10)
1.303(5)
1.322(3)
1.316(4)
1.718(4)
1.708(3)
1.714(4)
79.25(4)
78.51(3)
79.48(3)
85.61(15)
86.08(10)
85.11(13)
125.3(3)
125.36(11)
125.05(3)
109.5(2)
109.31(16)
109.9(2)
7
[Ni(bfdtc)(NCS)(PPh3)]
[Ni(dbpdtc)2]
3
8
This
work
4
[Ni(dbpdtc)(NCS)(PPh3)]
2.1914(15)
2.2095(15)
1.285(6)
1.730(5)
78.90(5)
86.57(18)
126.05(4)
107.8(3)
5
6
[Ni(thqdtc)2]
2.1941(6)
2.2068(5)
2.208(1)
2.1968(5)
2.1648(5)
2.198(1)
1.326(3)
1.316(2)
1.315(4)
1.315(3)
1.316(4)
1.316(2)
1.319(2)
1.717(2)
1.7115(17)
1.716(3)
79.34(2)
78.58(2)
79.02(5)
79.06(3)
79.42(3)
78.80(16)
79.188(16)
85.59(7)
86.59(6)
85.73(2)
85.90(9)
85.58(12)
86.29(6)
85.77(6)
125.26(16)
126.0(13)
125.3(3)
109.46(11)
107.96(9)
9
[Ni(thqdtc)(NCS)(PPh3)]
[Ni(thiqdtc)2]
7
109.52(18) 10
109.07(14) 11
8
[Ni(thiqdtc)(NCS)(PPh3)]
[Ni(achdtc)2]
2.2183(7)
2.2081(10)
2.1674.(5)
2.2108(4)
2.1620(7)
2.1897(10)
2.2299(5)
2.2004(5)
1.712(3)
125.45(2)
125.4(3)
12
9
1.723(4)
109.22(19)
108.53(9)
109.23(9)
10
11
[Ni(achdtc)(NCS)(PPh3)]
[Ni(echdtc)2]
1.7196(16)
1.7242(17)
125.73(12)
125.38(13)
13
12
13
[Ni(echdtc)(NCS)(PPh3)]
2.1779(7)
2.2127(7)
2.1854(8)
1.316(3)
1.314(3)
1.717(3)
1.715(3)
78.63(3)
78.97(3)
86.58(9)
125.9(2)
124.4(2)
108.21(4)
This
work
[Ni(bzcprdtc)(NCS)(PPh3)] 2.1742(7)
86.00(10)
108.96(15)
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