Translate this page into:
Ditopic dithiocarbamate ligands for the production of trinuclear species
⁎Corresponding author. hvaldes@live.com.mx (Hugo Valdés), damor@unam.mx (David Morales-Morales)
-
Received: ,
Accepted: ,
This article was originally published by Elsevier and was migrated to Scientific Scholar after the change of Publisher.
Peer review under responsibility of King Saud University.
Abstract
Abstract
Reactions of group 10 transition metals with the ditopic ligand dipicolyldithiocarbamate (DPDTC) were performed. Thus, 1:2 reactions of [Ni(CH3COO)2], [Pd(COD)Cl2] or [Pt(COD)Cl2] with DPDTC produced monomeric complexes of the type [M(κ2-SCS-DPDTC)2, M = Ni (1), Pd (2) or Pt (3)] with the dithiocarbamate ligand (DTC) coordinated in a typical chelate κ2-SCS fashion. Interestingly, the reaction of [NiCl2] with DPDTC, under similar conditions, afforded the organic compound 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyri-dine-3(2 H)-thione (4) as unique product. In order to prove the ditopic nature of the ligand DPDTC, complex [Pd(κ2-SCS-DPDTC)2] (2) was further reacted with [ZnCl2] in a 1:2 M ratio to yield the trinuclear complex [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5). The molecular structures of all compounds were determinate by typical analytical techniques including the unequivocal determination of all structures by single crystal X-ray diffraction analysis. As expected, complexes 1–3 are isostructural, and the metal centres exhibiting slightly distorted square-planar geometries. While in 5, the trinuclear nature of the complex in confirmed exhibiting a nice combination of tetrahedral-square planar-tetrahedral geometries for the Zn-Pd-Zn centres respectively.
Keywords
Dithiocarbamate
Metal-sulphur complexes
Trinuclear complexes
Ditopic ligands
Hetero-aromatic compound
Di-(2-picolyl)amine cyclization
1 Introduction
Ligands with two (ditopic) or more, different in nature, donating isolated fragments, have allowed the preparation of multimetallic species (Michl and Magnera, 2002; Lang et al., 2006, 2007; Packheiser et al., 2008a, 2008b, 2008c, 2008d, 2008e, 2008f, 2006; Packheiser and Lang, 2007; Wilton-Ely et al., 2008, 2005; Macgregor et al., 2009; Oliver et al., 2011; Hurtubise et al., 2014; Hogarth et al., 2009; Naeem et al., 2010a, 2010b, 2013; Anastasiadis et al., 2010; Knight et al., 2009a, 2009b, 2009c; Lin et al., 2014). These materials have been successfully employed as catalysts (Buchwalter et al., 2015) as well as for the preparation of sophisticate supramolecular architectures (Torres Huerta et al., 2013; Wong et al., 2005; Beer et al., 2003a, 2003b, 2001; Fox et al., 2000; Padilla Tosta et al., 2001). In this sense, procedures have been developed for the synthesis of multimetallic compounds with dithiocarbamate (DTC) ligands (A, Fig. 1) (Wilton-Ely et al., 2008, 2005; Macgregor et al., 2009). With this ligand, the synthesis of heterobimetallic complexes was performed in four steps starting from piperazine. First synthesizing one of the DTC, followed by its coordination with a transition metal. Then, the preparation of the second DTC and further coordination of the second metal was carried out. This procedure leads to the preparation of Ru/Os, Ru/Pd, Ru/Ni and Ru/Pt complexes in good yields. In latter reports ligand A has been found useful to coordinate other transition (Esmadi and Irshaidat, 2000; Siddiqi et al., 2006; Margotrigiano et al., 1975; Kovács et al., 2001; Yu et al., 2005) and non-transition metals (Yin et al., 2002; Yin and Wang, 2004; Tian et al., 2004).
Potentially ditopic DTC ligands.
However, to avoid a multistep procedure for the synthesis of multimetallic species, some research groups have prepared ligands that contain different donating atoms, since each donating group can be specific for a given metal. Thus, Wilton and co-workers have reported a series of metal complexes based on a diphosphine-dithiocarbamate “Janus” ligand (B, Fig. 1) (Sherwood et al., 2015). The ligand incorporates a dithiocarbamate moiety and a diphosphine-like fragment in the same molecule. The different nature of the coordinating moieties allowed the preparation of Pd/Pd, Ru/Re, Ru/Mo, Ru/W and Ru/Au complexes (Sherwood et al., 2015).
Among the bifunctional DTC ligands known to date, we considered the DTC derived from di-(2-picolyl)amine especially interesting, since it can act as potentially ditopic ligand, combining both a soft (SCS) and a relatively hard coordination sites. This ligand, dipicolyldithiocarbamate (DPDTC), (Fig. 1), was used for the preparation of its iron and cobalt derivatives (Vanthoeun et al., 2013). Finding the DPDTC coordinates to these metals exclusively through the sulphur atoms of the DTC functionality in a chelate fashion, with no coordination of the picolyl fragments observed. A similar behaviour has been observed when the analogous di(o-pyridyl)-dithiocarbamate (DPyDTC) (Poirier et al., 2015) was reacted with Pt(II), only producing the corresponding tetracoordinated [Pt(κ2-SCS-DPyDTC)2] dithiocarbamate complexes. To the best of our knowledge, the potential ditopic properties of DPDTC have not yet been described.
Thus, in this work, we describe the reactivity of the ligand DPDTC towards Ni(II), Pd(II) and Pt(II) and the further reactivity of the palladium derivative [Pd(κ2-SCS-DPDTC)2] (2) for the production of a trinuclear Zn(II)-Pd(II)-Zn(II) [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5) complex, hence exhibiting the ditopic nature of ligand DPDTC and providing a facile, high yield procedure for the attaining of multimetallic compounds.
2 Results and discussion
2.1 Synthesis of [M(κ2-SCS-DPDTC)2, M = Ni (1), Pd (2) or Pt (3)]
The synthesis of these complexes proceeds in a two steps single pot procedure from the reaction of di-(2-picolyl)amine with CS2 under basic conditions, to produce the potassium salt of ligand DPDTC which is then reacted in situ with the corresponding metal precursor (Scheme 1). The metallic complexes were isolated and characterized by NMR spectroscopy, mass spectrometry and elemental analysis.
Synthesis of metal complexes.
Reactions of [Ni(CH3COO)2], [Pd(COD)Cl2] or [Pt(COD)Cl2] with DPDTC produced complexes 1, 2, and 3 in 60%, 55% and 52% yields, respectively. Given the structural similarities of these three complexes, they also share similar spectroscopic properties. Thus, the 1H NMR spectrum of the three complexes shows one signal due to the —CH2— group at δ ∼5.0 ppm, while the signals due to the pyridine fragment appear in the expected frequencies. Moreover, the set of 13C NMR spectra displayed the distinctive DTC-carbon resonances at δ 210.3, 213.8 and 213.7 ppm for 1, 2 and 3 respectively. In the infrared spectra of these compounds, characteristic bands of νC—N at 1507, 1504 and 1511 cm−1 1, 2 and 3 respectively are observed. These values being typical for the presence of the DTC fragment. These spectroscopic information is well complemented with the results obtained from the FAB+ mass spectra recorded. The samples provide clean spectrums showing the molecular ions at m/z = 608.0 (1), 656.0 (2) and 743.1 (3). Finally, CHN analyses were also performed, fitting well with the expected percentages. All these results being coherent with the proposed formulations.
Additionally, the molecular structures of complexes 1, 2 and 3 were unambiguously determined by single crystal X-ray diffraction techniques (Fig. 2). Thus, the three complexes crystallize in a monoclinic system with C2/c centrosymmetric space group and are isostructural as is demonstrated by the similar cell parameters. The molecular structures with atom labelling are shown in Fig. 2. Crystallographic data, selected bond distances and H-bonds parameters are listed in Tables 1–3. For complexes 1, 2 and 3 Cg: N3, C9—C13.
The molecular structure of complexes 1, 2 and 3. The ellipsoids are drawing to 50%.
1
2
3
4
5
Empirical formula
C26H24N6NiS4
C26H24N6PdS4
C26H24N6PtS4
C13H11N3S
C26H24Cl4N6PdS4Zn2· CHCl3
Formula weight
607.46
655.15
743.84
241.31
1047.06
Temperature/K
150
150
100
296
150
Crystal system
Monoclinic
Monoclinic
Monoclinic
Orthorhombic
Monoclinic
Space group
C2/c
C2/c
C2/c
P212121
C2/c
a (Å)
13.6051(14)
13.7814(11)
13.7702(15)
4.3894(2)
26.0859(18)
b (Å)
15.6719(16)
15.6735(12)
15.6672(17)
11.5721(4)
9.4589(7)
c (Å)
12.5823(13)
12.535(1)
12.4755(13)
23.0255(9)
15.6631(10)
α (°)
90
90
90
90
90
β (°)
98.817(3)
98.155(2)
98.175(3)
90
103.455(2)
γ (°)
90
90
90
90
90
Volume (Å3)
2651.1(5)
2680.2(4)
2664.1(5)
1169.57(8)
3758.7(5)
Z
4
4
4
4
4
ρcalc (g/cm3)
1.522
1.624
1.855
1.370
1.850
μ (mm‑1)
1.076
1.033
5.609
0.256
2.490
F(000)
1256.0
1328
1456
504
2072
2θ range for data collection (°)
4.86–50.7
4.0–50.8
4.8–55.8
5.0–50.8
2.6–54.2
GOF
1.07
1.07
1.12
1.04
1.20
Rint
0.043
0.064
0.028
0.084
0.088
R1 I ≥ 2σ (I)
0.0354
0.0296
0.0210
0.0351
0.0678
wR2 I ≥ 2σ (I)
0.0808
0.0599
0.0460
0.0849
0.1205
Bond lengths (Å)
Bond angles (°)
1
Ni1—S1
2.1966(7)
S1Ni1S2
79.60(3)
Ni1—S2
2.2022(8)
S2Ni1S1a
100.40(3)
C1—N1
1.317(4)
S1C1S2
110.09(15)
C1—S1
1.717(3)
C1—S2
1.718(3)
2
Pd1—S1
2.3255(7)
S1Pd1S2
75.65(2)
Pd1—S2
2.3155(7)
S2Pd1S1a
104.35(2)
C1—N1
1.321(3)
S1C1S2
111.64(14)
C1—S1
1.720(3)
C1—S2
1.720(3)
3
Pt1—S1
2.3225(7)
S1Pt1S2
75.25(2)
Pt1—S2
2.3109(7)
S2Pt1S1a
104.75(2)
C1—N1
1.321(3)
S1C1S2
110.24(15)
C1—S1
1.722(3)
C1—S2
1.726(3)
D—H
A
D—H (Å)
H
A (Å)
D
A (Å)
DHA (°)
Symmetry code
1
C12—H12
S2
0.95
2.83
3.746(3)
163
1/2+x,1/2+y,z
C2—H2A
S1
0.99
2.87
3.816(3)
160
x,2−y,1/2+z
C4—H4
Cg
0.95
2.70
3.577(3)
155
x,2−y,1/2+z
C6—H6
S2
0.95
2.95
3.7142(3)
138
1/2−x,−1/2+y,1/2−z
C2—H2B
N3
0.99
2.74
3.6951(2)
163
1−x,y,1/2−z
2
C612—H12
S1
0.95
2.81
3.741(3)
165
−1/2+x,−1/2+y,z
C2—H2B
S2
0.99
2.83
3.781(3)
161
x,−y,−1/2+z
C4—H4
Cg1
0.95
2.69
3.574(3)
156
x,−y,−1/2+z
C6—H6
S1
0.95
2.94
3.708(3)
139
3/2−x,1/2+y,3/2−z
C2—H2A
N3
0.99
2.77
3.720(3)
161
1−x,y,3/2−z
3
C12—H12
S1
0.95
2.80
3.723(3)
164
1/2+x,−1/2+y,z
C2—H2B
S2
0.99
2.82
3.765(3)
161
x,−y,1/2+z
C4—H4
Cg
0.95
2.65
3.537(3)
156
x,−y,1/2+z
C6—H16
S1
0.95
2.93
3.691(3)
138
1/2−x,1/2+y,1/2−z
C2—H2A
N3
0.99
2.76
3.708(3)
160
1−x,y,1/2−z
4
C10—H10A
S1
0.95
2.99
3.827(3)
144
1+x,y,z
C6—H6
N11
0.99
2.66
3.509(4)
152
−x,−1/2+y,1/2−z
C4—H4
S1
0.99
2.99
3.850(3)
153
1−x,1/2+y,1/2−z
5
C10—H10
Cl2
0.95
2.90
3.778(8)
155
x,1+y,z
C7—H7A
Cl1
0.99
2.87
3.403(6)
115
1/2−x,1/2+y,1/2−z
C7—H7B
Cl2
0.99
2.82
3.664(7)
144
x,−y,1/2+z
C3—H3
Cl2
0.95
2.85
3.349(9)
117
x,−y,1/2+z
C5—H5
Cg
0.95
2.88
3.705(8)
146
x,−1+y,z
X-ray crystallographic analysis reveals the asymmetric unit in the three complexes to be half of the molecule with an inversion centre at the same position of the metal ion. The DPDTC ligands adopt, in all cases, a bidentate symmetric coordination mode linked to the metal through the sulphur atoms (S1, S2) with M-S distances of 2.1966(7) and 2.2022(8) Å for complex 1, 2.3255(7) and 2.3155(7) Å for complex 2, and 2.3225(7) and 2.3109(7) Å for complex 3. The coordination sphere of the metal ions is consisting of two DTC ligands to produce a tetracoordinated environment producing a slightly distorted planar square geometry to the metal centres. The two ligands give place to two chelate rings (S-C-S-M) with S1MS2 bite angles of 79.60(3), 75.65(2) and 75.25(2)° for complexes 1, 2 and 3 respectively. The C—S bond distances showed values between 1.717(3) and 1.726(3) Å, while the C—N bond distances are in the range of 1.317(4)–1.321(3) Å, which show the double bond character of these ligations.
The crystal arrangement of complexes 1, 2 and 3 is characterized by the presence of hydrogen bonds. One C—H⋯S interaction generates a 22-member macrocycles that are extended to give place to a linear framework as shown in Fig. 3. In the crystallographic analysis, it can be identified a second C—H⋯S interaction that forms a laminar array (Fig. 4). Additionally, the structures also presented one C—H⋯N interaction with the pyridyl nitrogen atoms and one π-π interaction between two pyridyl groups forming a linear array. The π-π interactions present distances values between centroids (Cg-Cg) of 3.667(2) [1 − x, y, ½ − z], 3.6709(16) [1 − x, y, 3/2 − z], and 3.6558(16) Å [1 − x, y, ½ − z] for the three complexes. The supramolecular arrangement is complemented with C—H⋯S and C—H···π interactions, and the geometric values of the hydrogen bonds are shown in Table 3.
Representation of the linear array by C—H···S interactions. The hydrogen bonds that not participles are omitted for clarity.
Representation of the laminar framework in complexes 1, 2 and 3.
Interestingly, when the reaction of DPDTC was carried out with [NiCl2] in place of [Ni(CH3COO)2], complex 1 was not obtained (Scheme 2). Instead, the product resulted to be the fused heterocyclic organic compound 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyri-dine-3(2H)-thione (4).![Synthesis of 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyridine-3(2 H)-thione (4).](/content/184/2020/13/1/img/10.1016_j.arabjc.2017.05.019-fig7.png)
Synthesis of 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyridine-3(2 H)-thione (4).
This compound was fully characterized by common spectroscopic techniques and its structure in solid-state unequivocally determined by single crystal X-ray diffraction techniques (Fig. 5). Compound 4 crystallizes in orthorhombic system and the space group P212121, the asymmetric unit is formed by one molecule of the compound that is represented in Fig. 5. The crystallographic data and the hydrogen bonds parameters are shown in Tables 1 and 3.
Molecular structure of compound (4). The ellipsoids are drawing to 30% of probability. Selected bond length (Å): S1—C1 1.674(3), N2—C1 1.357(3), N2—C3 1.374(3), N2—C10 1.456(3), N8—C1 1.373(3), N8—C7 1.378(3), N8—C9 1.401(3), N11—C12 1.325(3), N11—C16 1.338(4). Selected bond angles (°): C1N2C3 111.3(2), C1N2C10 123.5(2), C3N2C10 125.2(2), C1N8C7 127.3(2), C1N8C9 110.5(2), C7N8C9 122.2(2), C12N11C16 117.4(2), S1C1N2 128.6(2), S1C1N8 127.03(19), N2C1N8 104.3(2).
The analysis of the crystal structure shows the π-π interaction between the five-member N1C1N8C9C3 and six member N8C7C6C5C4C9 rings with distances Cg-Cg of 3.6153(17) Å [−1 + x, y, z]. This interaction leads to a linear motif along the [1 0 0] axe. The linear array is complemented by the C10—H10A⋯S1 interaction. The packing also identified the C6—H6⋯N11 and C4—H4⋯S1 interactions originating the crystal arrangement (Fig. 6).
Representation of the C10—H10A⋯S1 and π-π interactions in (4).
In this line, Wang and co-workers have previously described the synthesis of (4) and its fluorescence properties (Ma et al., 2014). However, they obtained (4) by a different procedure (Scheme 3) involving the use of NH4OH with reaction times of 10 h to produce 80% yield of (4). Noteworthy the fact that following the procedure described in this work, compound (4) can be obtained in only 3 h in higher yields.
2.2 Synthesis of [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5)
Driven by our interest in obtaining multimetallic complexes and to test the ditopic nature of ligand DPDTC, we carried out the reaction of the Pd(II) complex 2 with [ZnCl2] in methanol, and this reaction produced 5 in 40% yield (Scheme 4). The product was characterized by common spectroscopic techniques. The 1H NMR spectrum shows two groups of signals. The first one was assigned to the —CH2— fragment that appears as a singlet at δ 5.12 ppm, and the second one is observed as a group of signals on the aromatic region corresponding to the pyridyl moiety. In addition, the 13C NMR spectrum showed the characteristic signal of the DTC fragment at δ 213.3 ppm. Analysis by FT-IR spectroscopy of this compound provided a spectrum that exhibits a band at 1511 cm−1, which can be assigned to the νC—N of the DTC moiety. Mass spectroscopy analysis also provided further information, affording a spectrum that exhibits the molecular ion at 927.6 m/z, and all this information combined with the results from elemental analyses support the proposed structure.
Synthesis of the trinuclear complex (5).
As was the case with the monometallic complexes, we were able to obtain crystals suitable for their analysis by single crystal X-ray diffraction techniques. The molecular structure confirms the heterotrinuclear nature of complex 5, consisting of one palladium and two zinc atoms (Fig. 7). Complex 5 crystallized as a solvate with one molecule of chloroform (CHCl3), and relevant crystallographic data have been included in Table 1. The trinuclear complex crystallized in a monoclinic system (C2/c), and the asymmetric unit is composed of half of the molecule generating the other half by an inversion centre at the same position of the palladium atom. The palladium atom is tetracoordinated by two ligands DPDTC (S1,S2) in a slightly distorted square planar geometry as shown by the values of the angles S-Pd-S of 75.60(6) and 104.40(6)°. Similar to the mononuclear complexes, the DPDTC ligand is coordinated in a bidentate symmetric mode with distances Pd-S of 2.3183(18) and 2.3231(18) Å, and the two chelate rings (S-C-S-Pd) formed by the ligands exhibit S1-Pd1-S2 angles of 75.60(6)°. The dithiocarbamate motif (CNS2) is planar with bond distances of C—N of 1.312(8) Å and C—S of 1.723(6) and 1.724(6) Å. On the other hand, the zinc atoms are tetracoordinated into a distorted tetrahedral geometry. The coordination sphere is composed of two chloride ligands and two nitrogen atoms of the dipicolyldithiocarbamate ligand (DPDTC) forming an eighth-member ring. The Zn-Cl bond distances have values of 2.199(2) and 2.224(3) Å, while the Zn-N bond distances are of 2.070(6) and 2.089(6) Å.
The molecular structure of the trinuclear complex 5. The ellipsoids are drawing to 50% of probability. Selected bond lengths (Å): Pd-S1 2.3183(18), Pd-S2 2.3231(18), C1—N1 1.312(8), C1—S1 1.723(6), C1—S2 1.724(6), Zn1—N2 2.070(6), Zn1—N3 2.089(6), Zn1—Cl1 2.199(2), Zn1—Cl2 2.224(3). Selected bond angles (o): S1Pd1S2 75.60(6), S2Pd1S1a 104.40(6), S1C1S2 111.3(3), Cl1Zn1N2 110.14(17), Cl1Zn1N3 106.44(16), Cl2Zn1N2 100.76(17), Cl2Zn1N3 105.95(17), N2Zn1N3 115.6(2), Cl1Zn1Cl2 118.29(10).
In the supramolecular arrangement, there are two kinds of weak hydrogen bonds C—H⋯Cl and C—H⋯π interactions. The C10—H10⋯Cl2 and C7—H7A⋯Cl1 interactions join neighbour molecules to lead the formation of a layer. The C3—H3⋯Cl2 and C7—H7B⋯Cl2 interactions generate a layer parallel to the (0 1 1) plane (Fig. 8). The combination of all C—H⋯Cl interactions give place to the 3D framework, and is complemented by the interaction C—H⋯π(chelate) between the C5—H5 and the chelate ring PdS1C1S2 with a distance of 2.88 Å, this value agreeing well with other found in similar complexes exhibiting a square planar geometry around the metal centre (Tiekink and Zukerman-Schpector, 2012). Moreover, the solvent molecule is disordered in four positions in proportion (0.25/0.25/0.25/0.25), however this molecule may present interactions such as C—H⋯Cl and Cl⋯S, the bond distance on the Cl⋯S interactions present distances of 3.23 and 3.62 Å, values that are less or equal to the sum of van der Waals radius [3.6 Å].
Fragment of the layer array by C—H⋯Cl interactions in 5.
In summary, a set of metal complexes bearing dipicolyldithiocarbamate ligand (DPDTC) were prepared and fully characterized, including the unequivocal determination of their solid-state structures by single crystal X-ray diffraction techniques, were the triad of Ni(II) (1), Pd(II) (2) and Pt(II) (3) DPDTC complexes were found to be isostructural. In addition, the ditopic nature of ligand DPDTC was proved, thus, by reacting Pd(II) complex 2 with two equivalents of ZnCl2, we were able to produce the heterotrinuclear complex [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5). It can be envisaged that by careful selection of the metals and their substituents we have on hand a versatile system which may find applicability for the production of scaffolds for the preparation of new metallosupramolecular frameworks or heterometallic catalysts. Some of these experiments are currently being performed in our laboratory and the results will be disclosed in due time.
Furthermore and not less interesting, we have described a facile and high yield synthesis of the heteroaromatic compound 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyridine-3(2H)-thione (4) catalysed by NiCl2. Efforts to expand the scope of this reaction to other similar substrates and to shed some light into the mechanistics involved on this transformation are also under study in our group.
3 Experimental section
All chemical compounds were commercially obtained from Aldrich Chemical Co. and used as received without further purification. The 1H and 13C{1H} NMR spectra were recorded on a JEOL GX300 spectrometer. Chemical shifts are reported in ppm down field of TMS using the residual signals in the solvent (CDCl3, δ 7.27) as internal standard. Elemental analyses were performed on a Perkin Elmer 240. CHNS analyses were performed in a Thermo Scientific Flash 2000 elemental analyzer, using a Mettler Toledo XP6 Automated-S Microbalance and sulfanilamide as standard (Thermo Scientific BN 217826, attained values N = 16.40%, C = 41.91%, H = 4.65%, and S = 18.63%; certified values N = 16.26%, C = 41.81%, H = 4.71%, and S = 18.62%). Positive-ion FAB mass spectra were recorded on a JEOL JMS-SX102A mass spectrometer operated at an accelerating voltage of 10 kV. Samples were desorbed from a nitrobenzyl alcohol (NOBA) matrix using 3 keV xenon atoms. Mass measurements in FAB+ are performed at a resolution of 3000 using magnetic field scans and the matrix ions as the reference material or, alternatively, by electric field scans with the sample peak bracketed by two (polyethylene glycol or cesium iodide) reference ions. MS-DART experiments were recorded on a JEOL AccuTOF JMS-T100LC mass spectrometer, while the MS-Electrospray determinations were recorded on a Bruker Daltonics-Esquire 3000 plus Electrospray Mass Spectrometer.
3.1 General procedure for the synthesis of complexes [M(κ2-SCS-DPDTC)2, M = Ni (1), Pd (2) or Pt (3)]
A solution of bis(pyridin-2-ylmethyl)amine (0.15 mmol, 30 mg) and NaOH (0.175 mmol, 7.0 mg) in 20 mL of ethanol was stirred at room temperature for 30 min. Then, CS2 (0.30 mmol, 0.1 mL) was added to the reaction mixture at 0 °C. The reaction was stirred for 2 h at room temperature. After which time 20 mL of an ethanol solution of the metal precursor (7.5 mM) was added. The resulting reaction mixture was stirred for 3 h at room temperature. After this time, the precipitated solid was collected by filtration and washed with small amounts of ethanol (3 × 10 mL).
3.1.1 [Ni(κ2-SCS-DPDTC)2] (1)
Yield: 109.4 mg (60%). 1H NMR (300 MHz, CDCl3) δ 8.49 (d, J = 4.7 Hz, 4H, CHAr), 7.62 (td, J = 7.7, = 1.8 Hz, 4H, CHAr), 7.29 (d, J = 7.8 Hz, 4H, CHAr), 7.18–7.11 (m, 4H, CHAr), 4.93 (s, 8H, —CH2—). 13C NMR (126 MHz, CDCl3) δ 210.3 (N-CS2), 154.3 (CHAr), 149.8 (CHAr), 137.1 (CHAr), 123.1 (CHAr), 122.9 (CHAr), 53.9 (—CH2—). MS-FAB+: m/z = 608.0 [M]+. Anal Calcd for C26H25N6NiS4·6H2O: C, 51.41; H, 3.98; N, 13.83; S, 21.11. Found: C: 51.43, H: 4.00, N: 13.79, S: 21.09.
3.1.2 [Pd(κ2-SCS-DPDTC)2] (2)
Yield: 108.5 mg (55%). 1H NMR (300 MHz, CDCl3) δ 8.49 (d, J = 4.8 Hz, 4H, CHAr), 7.61 (td, J = 7.7, 1.8 Hz, 4H, CHAr), 7.29 (d, J = 7.8 Hz, 3H, CHAr), 7.18–7.09 (m, 4H, CHAr), 5.05 (s, 8H, —CH2—). 13C NMR (126 MHz, CDCl3) δ 213.8 (N-CS2), 154.3 (CHAr), 149.8 (CHAr), 137.1 (CHAr), 123.1 (CHAr), 122.8 (CHAr), 54.2 (—CH2—). MS-FAB+: m/z = 656.0 [M]+. Anal Calcd for C26H24N6PdS4: C, 47.66; H, 3.69; N, 12.83; S, 19.58. Found: C: 47.63, H: 3.67, N: 12.84, S: 19.55.
3.1.3 [Pt(κ2-SCS-DPDTC)2] (3)
Yield: 111.5 mg (52%). 1H NMR (300 MHz, CDCl3) δ 8.61–8.53 (m, 4H, CHAr), 7.74–7.63 (m, 4H, CHAr), 7.39 (d, J = 7.8 Hz, 4H, CHAr), 7.25–7.17 (m, 4H, CHAr), 4.99 (s, 4H, —CH2—) 4.98 (s, 4H, —CH2—). 13C NMR (126 MHz, CDCl3) δ 213.7 (N-CS2), 152.9 (CHAr), 148.8 (CHAr), 136.1, (CHAr) 122.2 (CHAr), 121.9 (CHAr), 53.2 (—CH2—). MS-FAB+: m/z = 743.1 [M]+. Anal Calcd for C26H24N6PtS4: C, 41.98; H, 3.25; N, 11.30; S, 17.24. Found: C: 42.02, H: 3.35, N: 11.25, S: 17.18.
3.2 2-(Pyridin-2-ylmethyl)imidazo[1,5-a]pyridine-3(2H)-thione (4)
A solution of di-(2-picolyl)amine (1 mmol, 199.3 mg), NiCl2·6H2O (1 mmol, 237.7 mg) in 2 mL of ethanol was stirred at room temperature for 3 h. After this time, the crystalline solid was filtered and washed with small amounts of cold ethanol. Yield: 219.6 mg (90%). 1H NMR (300 MHz, CDCl3) δ 8.58 (d, J = 7.2 Hz, 1H, CHAr), 8.29 (d, J = 8.3 Hz, 1H, CHAr), 7.66 (td, J = 7.8, 2.0 Hz, 1H, CHAr), 7.45 (d, J = 8.4 Hz, 1H, CHAr), 7.26–7.20 (m, 1H, CHAr), 7.18 (s, 1H, CHAr) 7.12 (d, J = 9.7 Hz, 1H, CHAr), 6.84–6.68 (m, 1H, CHAr), 6.53 (t, J = 7.5 Hz, 1H, CHAr), 5.66 (s, 2H, —CH2—). 13C NMR (76 MHz, CDCl3) δ 155.1 (CS), 153.8 (CAr), 149.7 (CHAr), 137.2 (CHAr), 127.7 (CAr), 125.5 (CHAr), 123.6 (CHAr), 123.3 (CHAr), 122.5 (CHAr), 117.4 (CHAr), 112.3 (CHAr), 107.0 (CHAr), 53.1 (—CH2—). Electrospray MS (20 V, m/z): 241.9 [M+H]+. Anal Calcd for C13H11N3S: C, 64.70; H, 4.59; N, 17.41; S, 13.29. Found: C, 64.64; H, 4.57; N, 17.34; S, 13.31.
3.3 Synthesis of [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5)
A solution of 2 (0.05 mmol, 30 mg) and ZnCl2 (0.1 mmol, 13.6 mg) in 30 mL of ethanol was stirred at room temperature during 1 h. Yield: 18.6 mg (40%). 1H NMR (500 MHz, CDCl3) δ 8.91 (d, J = 4.9 Hz, 4H, CHAr), 7.86–7.80 (m, 4H, CHAr), 7.42–7.39 (m, 4H, CHAr), 7.28 (d, J = 7.4 Hz, 4H, CHAr), 5.12 (s, 8H, —CH2—). 13C NMR (126 MHz, CDCl3) δ 213.3 (N-CS2), 154.3 (CHAr), 147.9 (CHAr), 138.8 (CHAr), 124.2 (CHAr), 121.9 (CHAr), 51.16 (—CH2—). MS-DART: m/z = 927.6 [M]+. Anal Calcd for C26H24Cl4N6PdS4Zn2: C, 33.66; H, 2.61; N, 9.06; S, 13.82. Found: C, 33.57; H, 2.59, N, 9.02; S: 13.79.
3.4 Data collection and refinement for compounds 1–5
Diffraction data for compounds 1, 2, 4 and 5 were recorded on a Bruker SMART APEX I CCD area detector diffractometer (Mo-Kα graphite-monochromated radiation, λ = 0.71073 Å), and data for compounds 1, 2 and 5 were collected at 150 K, while data for compound 4 were collected at 296 K. For compound 3 data collection was recorded at 100 K using a Bruker D8 Venture diffractometer (Mo-Kα graphite-monochromated radiation, λ = 0.71073 Å). For all compounds APEX2 (APEX2, 2014) and SAINT (SAINT+, 2014) were used for data collection and cell refinement and for data reduction respectively. The structures were solved and refined using SHELXL (SHELXS-2012, 2013; Sheldrick, 2015) software. All non-hydrogen atoms were refined anisotropically, and hydrogen atoms bound to carbon were placed at their idealized positions using appropriate HFIX instructions in SHELXL: 43 (aromatic carbon atoms), or 23 (for methylene groups). These hydrogen atoms were included in subsequent refinement cycles with isotropic thermal displacement parameters (Uiso) fixed at 1.2. In compound 4 the solvent molecule (CHCl3) is disordered over four sites with occupancy ratio of 0.25:0.25:0.25:0.25. All presented analysis of interaction and supramolecular array were made using PLATON (Spek, 2009) and MERCURY (Macrae et al., 2006) programs and the graphics were prepared using DIAMOND (Brandenburg and Berndt, 1999) program.
Acknowledgments
We would like to thank Chem. Eng. Luis Velasco Ibarra, Dr. Francisco Javier Pérez Flores, Q. Eréndira García Ríos, M.Sc. Lucia del Carmen Márquez Alonso, M.Sc. Lucero Ríos Ruiz, M.Sc. Alejandra Núñez Pineda (CCIQS), Q. María de la Paz Orta Pérez and Q. Roció Patiño-Maya for technical assistance. H. V. would like to thank Programa de Estancias Posdoctorales en México CONACYT-SENER-Hidrocarburos 2015-2016 (Oficio: COIC/CSGC/1244/16) and Programa de Becas Posdoctorales-DGAPA-UNAM for a postdoctoral scholarships (Oficio: CJIC/CTIC/1060/2017). EM-C would like to thank CONACYT for M.Sc. scholarship. The financial support of this research by PAPIIT (Grants No. IN213214) is gratefully acknowledged.
References
- Inorg. Chim. Acta. 2010;363:3222-3228.
- APEX2 Data Collection Software, Version 2014.1-1, Bruker AXS, Delft, The Netherlands, 2014.
- Chem. Commun.. 2001;2001:199-200.
- Chem. Commun.. 2003;2003:2408-2409.
- Dalton Trans.. 2003;2003:603-611.
- J. Appl. Cryst.. 1999;32:1028-1029.
- Chem. Rev.. 2015;115:28-126.
- Synth. React. Inorg. Metal-Org. Chem.. 2000;30:1347-1362.
- Angew. Chem. Int. Ed. Engl.. 2000;39:135-140.
- Inorg. Chim. Acta. 2009;362:2020-2026.
- Inorg. Chem.. 2014;53:11740-11748.
- Dalton Trans.. 2009;2009:607-609.
- Dalton Trans.. 2009;2009:3688-3697.
- Inorg. Chem.. 2009;48:3866-3874.
- Organometallics. 2001;20:35-41.
- Organometallics. 2006;25:1836-1850.
- J. Organomet. Chem.. 2007;692:4168-4176.
- Eur. J. Inorg. Chem.. 2014;2014:2065-2072.
- RSC Adv.. 2014;4:59961-59964.
- Organometallics. 2009;28:197-208.
- J. Appl. Cryst.. 2006;39:453-457.
- Bull. Chem. Soc. Jpn.. 1975;48:1018-1020.
- Proc. Natl. Acad. Sci. USA. 2002;99:4788-4792.
- Dalton Trans.. 2010;39:4080-4089.
- Inorg. Chem.. 2010;49:1784-1793.
- Inorg. Chem.. 2013;52:4700-4713.
- Dalton Trans.. 2011;40:5852-5864.
- Eur. J. Inorg. Chem. 2007:3786-3788.
- Organometallics. 2006;25:4579-4587.
- Chem. Ber.. 2008;2008:4152-4165.
- Organometallics. 2008;27:1214-1226.
- Chem. Eur. J.. 2008;14:4948-4960.
- J. Organomet. Chem.. 2008;693:933-946.
- Organometallics. 2008;27:3444-3457.
- Organometallics. 2008;27:3534-3546.
- Angew. Chem. Int. Ed. Engl.. 2001;40:4235-4239.
- Inorg. Chem.. 2015;54:3728-3735.
- SAINT+, Data Integration Engine, version V8.34A, Bruker AXS, Madison, Wisconsin, USA, 2014.
- Acta Crystallogr., Sect. C: Cryst. Struct. Commun.. 2015;71:3.
- SHELXS-2012. Program for Crystal Structure Solution. Bruker AXS, Madison, Wisconsin, USA, 2013.
- Inorg. Chem.. 2015;54:4222-4230.
- Synth. React. Inorg. Metal-Org. Chem.. 2006;10:569-578.
- Acta. Crystallogr.. 2009;D65:148-155.
- Appl. Organometal. Chem.. 2004;18:253-254.
- Tiekink, E.R.T., Zukerman-Schpector, J. (Eds.), The Importance of Pi-Interactions in Crystal Engineering: Frontiers in Crystal Engineering. John Wiley & Sons Ltd, Publication, pp. 275–300.
- I. F. Hernández Ahuactzi, M. Sánchez, R. Reyes Martínez and D. Morales Morales. Eur. J. Inorg. Chem.. 2013;2013:61-69.
- [Google Scholar]
- J. Coor. Chem.. 2013;66:2378-2387.
- Eur. J. Inorg. Chem.. 2005;2005:4027-4030.
- Inorg. Chem.. 2008;47:9642-9653.
- Dalton Trans.. 2005;2005:359-364.
- Appl. Organometal. Chem.. 2004;18:145-146.
- Acta Chim. Sin.. 2002;60:897-903.
- J. Am. Chem. Soc.. 2005;127:17994-17995.