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Article

Synthesis, X-ray Structure, Hirshfeld Surface Analysis and Antimicrobial Assessment of Tetranuclear s-Triazine Hydrazine Schiff Base Ligand

by
Hessa H. Al-Rasheed
1,*,
Sarah A. AL-khamis
1,
Ayman El-Faham
2,
Assem Barakat
1,
Alexandra M. Z. Slawin
3,
John Derek Woollins
3,4 and
Saied M. Soliman
2,*
1
Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
2
Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321, Egypt
3
School of Chemistry, University of St Andrews, Andrews KY16 9ST, UK
4
Department of Chemistry, Khalifa University, Abu Dhabi 999041, United Arab Emirates
*
Authors to whom correspondence should be addressed.
Inorganics 2023, 11(9), 357; https://doi.org/10.3390/inorganics11090357
Submission received: 11 August 2023 / Revised: 23 August 2023 / Accepted: 28 August 2023 / Published: 30 August 2023
Browse Figures
Versions Notes

Abstract

:
The unexpected tetranuclear [Cu4(DPPT)2Cl6] complex was obtained by self-assembly of CuCl2.2H2O and (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine, (HDPPT) in ethanol. In this tetranuclear [Cu4(DPPT)2Cl6] complex, the organic ligand acts as mononegative chelate bridging two crystallographically independent Cu(II) sites. The DPPT− anion acts as a bidentate ligand with respect to Cu(1), while it is a tridentate for Cu(2). The Cu(1)N2Cl3 and Cu(2)N3Cl spheres have square pyramidal and square planar coordination geometries with some distortion, respectively. Two of the chloride ions coordinating the Cu(1) are bridging between two crystallographically related Cu(1) sites connecting two [Cu2(DPPT)Cl3] units together, leading to the tetranuclear formula [Cu4(DPPT)2Cl6]. The packing of the [Cu4(DPPT)2Cl6] complex is dominated by C-H…Cl contacts, leading to one-dimensional hydrogen-bond polymeric structure. According to Hirshfeld surface analysis of molecular packing, the non-covalent interactions H…H, Cl…H, Cl…C, C…H, and N…H are the most significant. Their percentages are 52.8, 19.0, 3.2, 7.7, and 9.7%, respectively. Antimicrobial assessment showed good antifungal activity of the Cu(II) complex against A. fumigatus and C. albicans compared to Ketoconazole as positive control. Moreover, the [Cu4(DPPT)2Cl6] complex has higher activity against Gram-positive bacteria than Gentamycin as positive control. The opposite was observed when testing the tetranuclear [Cu4(DPPT)2Cl6] complex against the Gram-negative bacteria.

1. Introduction

Supramolecular chemistry is concerned with the chemistry beyond the molecule. It focuses on the assembly of molecular systems via non-covalent interactions. Currently, Supramolecular chemistry is considered a well-accepted discipline in chemistry due to the diverse applications in different areas, such as gas absorption, nanoreactors, molecular sensors, chemical catalysis, drug delivery, and molecular machines [1]. Moreover, this field of chemistry has applications in maintenance-free materials [2,3], molecular encapsulation [4,5], and medical diagnostic sensors [6]. Hence, this growing branch of chemistry is found in a variety of daily uses where its applications extend to sensors, medicine, materials, and extraction technologies [7]. Coordination compounds attract the attention of scientists as a consequence of their wide range of applications in diverse fields [8,9,10,11,12,13,14,15]. Copper is an important metal in coordination chemistry as well as in biology [16,17,18,19]. Its compounds are recommended as therapeutic agents for treatments of many diseases, including microbial infections [20,21,22,23], lung inflammation [24], influenza A [25], cancer [26], and others [27,28,29,30]. Copper has a high ability to form coordination compounds where its coordination environment is dependent on many factors, including its oxidation state, ligand nature, and medium used [31,32].
On the other hand, heterocyclic compounds are important organic compounds used in coordination chemistry as ligands to build interesting metal-organic systems [33,34,35,36]. Moreover, Schiff base compounds have great importance in coordination chemistry in addition to their diverse applications in different areas, including industrial food, chemosensors, polymer stabilizers catalysis transformation, pigments and dyes, and also as starting materials for synthesizing a wide range of biologically active compounds [37]. The introduction of heterocyclic moiety in a Schiff base derivative produces powerful chelating ligands with higher chelation capacity for the synthesis of metal-organic complexes. In this regard, the six-membered aromatic ring with alternating C and N-atoms, which is known as s-triazine, has attracted the attention of researchers in supramolecular chemistry for molecular assembly to construct interesting metal-organic architectures. Hence, many s-triazine chelating ligands were designed for the construction of metal complexes with fascinating applications and interesting biological activities [38].
Recently, our research group studied the coordination chemistry of some s-triazine Schiff base ligands, exploring their coordination chemistry towards different metal ions and showing their molecular and supramolecular characteristics (Scheme 1) [39,40,41,42,43]. Among these s-triazine Schiff base ligands, the 2,4-bis(morpholin-4-yl)-6-[(E)-2-[1-(pyridin-2-yl)ethylidene]hydrazin-1-yl]-1,3,5-triazine (DMPT) form a number of metal complexes with Ni(II), Cu(II), Cd(II), Zn(II), and Mn(II) metal salts. In all cases, the structure of the resulting complexes was approved using a single crystal X-ray structure to be monomeric and the ligand acting as a neutral tridentate NNN-chelate.
Furthermore, the bis-piperidino analog ((E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine, (HDPPT)) formed mononuclear complexes with Ni(II) and also behaved as a neutral tridentate NNN-chelate (Scheme 2) [41]. As a continuation of our previous studies on the bis-piperidino analog ligand, we tested the reaction of this ligand with copper chloride dihydrate using the same reaction conditions. The resulting complex was isolated in good crystallinity, allowing the confirmation of the structure using single-crystal X-ray diffraction in addition to FTIR spectra and elemental analyses. In addition, the supramolecular structure of this complex was analyzed using Hirshfeld surface analysis. The activity of the synthesized complex against some harmful microbes is examined.

2. Results and Discussion

2.1. Synthesis and Characterization

In our previous studies, the synthesis including X-ray structure characterization and antimicrobial activities of the self-assembled monomeric complexes [Ni(HDPPT)2](NO3)2*1.5H2O and [Ni(HDPPT)(NO3)Cl].EtOH was presented. The two Ni(II) complexes were prepared by reaction of Ni(II) salts with HDPPT ligand in ethanol [41]. The HDPPT ligand acts as a neutral tridentate chelate in both cases. In this work, self-assembly of the HDPPT ligand and copper chloride dihydrate in ethanol afforded the tetranuclear [Cu4(DPPT)2Cl6] complex as dark green crystals after one week of slow evaporation at room temperature (Scheme 3). Unlike the corresponding [Ni(HDPPT)2](NO3)2*1.5H2O and [Ni(HDPPT)(NO3)Cl].EtOH complexes of the same ligand, the NH proton of the ligand was deprotonated during the course of the reaction. Hence, the ligand in the case of the current Cu(II) complex is acting as a mononegative ligand but not a neutral one as found in the Ni(II) complexes. FTIR spectra of the [Cu4(DPPT)2Cl6] complex revealed the deprotonation of the HDPPT ligand. The ν(N-H) vibration of the ligand was detected at 3279 cm−1, this band completely disappeared in the [Cu4(DPPT)2Cl6] complex. Moreover, the ν(C=N) and ν(C=C) modes were detected at 1597 and 1514 cm−1, respectively, for the free HDPPT ligand. The corresponding values for the tetranuclear [Cu4(DPPT)2Cl6] complex are 1549 and 1515 cm−1, respectively. It is clear that the ν(C=N) mode was shifted to a lower wavenumber due to complexation with the Cu(II) ion, while the ν(C=C) showed almost no shift.

2.2. X-ray Structure Description

The crystal structure of the newly synthesized complex approved, with no doubt, the unexpected formation of the tetranuclear Cu(II) complex of the formula [Cu4(DPPT)2Cl6]. The asymmetric formula of this complex is half of this molecular unit, and the complex crystallized in the monoclinic crystal system, and the space group is P21/c. The unit cell parameters are a = 12.9169(9) Å, b = 19.6681(12) Å, c = 9.7335(6) Å, and β = 96.8998(19)° while z = 2. The unit cell volume is 2454.9(3) Å3, and the crystal density is 1.658 Mg/m3. The presentation of the asymmetric formula and the complete molecular structure view of the studied complex are shown in Figure 1.
In the [Cu4(DPPT)2Cl6], there are two Cu(II) centers with different coordination environments, which are the Cu(1) and Cu(2) atomic sites. The Cu(2) atom is tetra-coordinated with the three N-atoms N1, N9 and N12 where the respective copper to nitrogen distances are 1.9899(16), 1.9539(15), and 1.9940(15) Å, while the two bite angles N1-Cu2-N9 and N12-Cu2-N9 are 80.22(6) and 79.38(6)°, respectively and the trans N1-Cu2-N12 angle is 156.68(6)°. The coordination sphere of the Cu(2) is completed by one chloride ligand (Cl3) where the Cu2-Cl3 distance is 2.2156(5) Å and the Cl3-Cu2-N9 angle is 159.92(5)°. The distortion of the coordination geometry around the Cu(2) site is described by τ4 parameter using the equation τ4 = −0.00709α − 0.00709β + 2.55 reported by Houser et al. [44]. Using the values of α and β, which are the two greatest valence angles, the τ4 is estimated to be 0.21. Hence, the structure of the coordination environment of the Cu(2) is more close to a distorted square planar geometry. On the other hand, the Cu(1) is pentacoordinated with CuN2Cl3 coordination sphere. While the organic DPPT− ligand anion is acting as a tridentate chelate with respect to Cu(2) site, the same ligand unit acting as a bidentate chelate for the Cu(1) site via the short Cu1-N10 (1.9702(15) Å) and the relatively long Cu1-N16 (2.643(2) Å) bonds. The bite angle N16-Cu1-N10 is 56.47(5)°. In the case of Cu(1) site, there are three coordinated chloride ions as ligands, which are the Cl2, Cl1, and Cl1# (Symm. code #: 2-X, 1-Y, 1-Z). The corresponding Cu-Cl distances are 2.2291(5), 2.2801(5), and 2.3144(5) Å. The details of the bond angles, along with the Cu-N and Cu-Cl distances, are depicted in Table 1. Based on the τ5 parameter, which is used as a descriptor for describing the distortion in five coordinated systems, the CuN2Cl3 coordination sphere of the Cu(1) site is closer to the square pyramidal with τ5 parameter of 0.15 employing Addison equation: τ5 = −0.01667α + 0.01667β where β and α are the N10-Cu1-Cl1 (160.21(2)°) and Cu1-Cl1-Cu2 (151.04(2)°), respectively [45]. It is worth noting that the tetranuclear formula [Cu4(DPPT)2Cl6] is formed by the bridged Cl1 atoms, which connect two of the asymmetric formulas via the Cu1-Cl1 bonds. Moreover, the organic ligand DPPT− ligand anion acts as a connector between the Cu(1) and Cu(2) sites.
The packing of the tetranuclear [Cu4(DPPT)2Cl6] units in the crystal is dominated by the C3-H3…Cl2 contact shown in Figure 2A. The Cl2…H3 distance is 2.64 Å, while the acceptor Cl2 to donor C3 distance is 3.549(2) Å. The view of the one-dimensional hydrogen bond polymeric structure is presented in Figure 2B.

2.3. Analysis of Molecular Packing

Crystalline materials are characterized by specific forces which hold the crystal stable and keep the molecules in a definite and unique arrangement in the three dimensions. Hirshfeld analysis is a very interesting tool to characterize these forces that hold the molecules in the crystal structure. Different Hirshfeld maps are presented in Figure 3. In the dnorm map of the tetranuclear [Cu4(DPPT)2Cl6] complex, there are several red spots characteristic for the short H…H (A), Cl…H (B), Cl…C (C), C…H (D), and N…H (E) interactions, which are considered evidence of the significance of these non-covalent interactions on the crystal structure stability of the tetranuclear [Cu4(DPPT)2Cl6] complex. The H24A…H22B (2.138 Å), Cl1…C5 (3.403 Å), Cl2…H3 (2.513 Å), C15…H20A (2.599 Å), and N16…H20A (2.572 Å) have shorter distances than the sum of the van der Waals radii sum of the two atoms sharing in these interactions (Table 2). We noted one weak C…H contact with a slightly longer interaction distance than the sum of the hydrogen and carbon van der Waals’s radii sum. The C15…H4 contact has an interaction distance of 2.810 Å, while the vdWs radii sum of the H and C atoms is 2.79 Å.
On the other hand, the fingerprint plot obtained from the Hirshfeld analysis enabled us not only to predict the significant interactions but also to estimate the percentage of each contact in the crystal structure. The H…H, Cl…H, Cl…C, C…H, and N…H contacts appeared as sharp spikes, revealing their importance (Figure 4). It is clear that the decomposed fingerprint plots of the H…H, Cl…H, Cl…C, C…H, and N…H contacts appeared as two sharp spikes. This pattern for the fingerprint plots indicates that these interactions and their reciprocals are significant and occur at short distances.
On the other hand, the decomposition of the fingerprint plot gave the percentages of all possible interactions that could occur in the crystal structure. The presentation of all possible intermolecular contacts is shown in Figure 5. In addition, the percentages of these interactions are also presented in the same figure. The results indicated that the H…H and Cl…H interactions are the most dominant. Their percentages were estimated to be 52.8 and 19.0%, respectively. On the other hand, the percentage of the C…H, Cl…C, and N…H interactions are 7.7, 3.2, and 9.7%, respectively.
In addition, other weakly contributing intermolecular contacts such as the Cu…Cl, Cu…C, Cu…H, Cl…N, and C…N contacts were detected in the crystal structure of the [Cu4(DPPT)2Cl6] complex. Their percentages were found to be 0.6, 1.1, 0.5, 2.3, and 1.4%, respectively. Their percentages are small and appear as blue or white regions in the dnorm map, revealing weak and less important non-covalent interactions in the molecular packing of the [Cu4(DPPT)2Cl6] complex.

2.4. Antimicrobial Studies

Assessment of the [Cu4(DPPT)2Cl6] complex and the free ligand HDPPT against some dangerous microbes was performed by detecting the inhibition zone diameters. The results are depicted in Table 3. The presence of inhibition zones with different sizes for the [Cu4(DPPT)2Cl6] complex indicated its broad-spectrum antimicrobial actions against the tested bacteria and fungi. In contrast, the free ligand HDPPT has no broad action against these microbes. The free ligand HDPPT is only active against B. subtilis. In this case, the size of the inhibition zone is only 10 mm indicating weak action against this microbe. For the rest of the studied microbes, no inhibition zones were detected for the free ligand HDPPT. In contrast, the [Cu4(DPPT)2Cl6] complex has zones of inhibitions with comparable sizes to the antifungal Ketoconazole and antibacterial Gentamycin as positive controls. The only exception from this observation is E. coli. For the fungal species A. fumigatus and C. albicans, the inhibition zone diameters in the case of the [Cu4(DPPT)2Cl6] complex are 17 and 19 mm, respectively, while for Ketoconazole, the respective values are 17 and 20 mm. Interestingly, the [Cu4(DPPT)2Cl6] complex has a better MIC value than Ketoconazole for A. fumigatus, indicating higher potency of the Cu(II) complex against this microbe. On the other hand, the [Cu4(DPPT)2Cl6] complex and Ketoconazole have the same MIC value for C. albicans. These results indicated the high antifungal activity of the [Cu4(DPPT)2Cl6] complex against both fungal species. On the other hand, the Ni(II) complexes of the same ligand showed comparable antifungal activity against C. albicans compared to the [Cu4(DPPT)2Cl6] complex. For the rest of the studied microbes, the Ni(II) complexes of the same ligand showed moderate antimicrobial activities compared to Ketoconazole and Gentamycin as positive controls [41] and are generally less potent than the [Cu4(DPPT)2Cl6] complex.
Regarding the antibacterial activity, the [Cu4(DPPT)2Cl6] complex (26 mm) has slightly better antibacterial activity against S. aureus than Gentamycin (24 mm). The MIC value of the former is smaller than that of the latter, which reveals the higher potency of the [Cu4(DPPT)2Cl6] complex against S. aureus than Gentamycin. For B. subtilis, the inhibition zone diameter and MIC values are determined to be 25 mm and 9.7 μg/mL, respectively, which are close to Gentamycin. In this regard, the [Cu4(DPPT)2Cl6] complex has good action against the Gram-positive bacteria, which is generally comparable to Gentamycin. In contrast, the inhibition zone diameters for the [Cu4(DPPT)2Cl6] complex against E. coli and P. vulgaris are determined to be 20 and 22 mm, respectively, while for Gentamycin, the corresponding values are 30 and 25 mm, respectively. Moreover, the MIC values are higher for the Cu(II) complex than Gentamycin (Table 3). Hence, the antibacterial activity of the [Cu4(DPPT)2Cl6] complex against Gram-negative bacteria is generally lower than the positive control Gentamycin.

3. Materials and Methods

3.1. Physical Measurements

All the chemicals were bought from Sigma-Aldrich and used without additional purifications. CHN analyses were carried out using a PerkinElmer 2400 Elemental Analyzer. The metal content was determined with the aid of a Shimadzu atomic absorption spectrophotometer (AA-7000 series, Shimadzu, Ltd., Tokyo, Japan). FTIR spectra were recorded at the Central Lab, Faculty of Science, Alexandria University, using a Bruker Tensor 37 FTIR spectrophotometer (Bruker Company, Berlin, Germany) in KBr pellets at 4000–400 cm−1 (Figures S1 and S2; Supplementary Materials).

3.2. Preparation of HDPPT

The HDPPT was prepared following the procedure reported in our previous work [41].

3.3. Synthesis of [Cu4(DPPT)2Cl6] Complex

Ethanolic solution of the organic ligand HDPPT (190.3 mg, 0.5 mmol in 10 mL) was mixed with CuCl2.2H2O (85.2 mg, 0.5 mmol) in 5 mL ethanol. The clear mixture was left at room temperature (25 °C) for a week, dark green crystals of the [Cu4(DPPT)2Cl6] complex were obtained and separated from the solution by filtration. The crystals were found suitable for the X-ray single crystal structure measurement.
[Cu4(DPPT)2Cl6]: 81.2% with respect to CuCl2.2H2O, Anal. Calc. C40H54Cl6Cu4N16: C, 39.19; H, 4.44; N, 18.28; Cu, 20.74%. Found: C, 38.89; H, 4.32; N, 18.01; Cu, 20.55%. IR (KBr, cm−1): 3061, 3002, 2973, 2855, 1549 and 1515.

3.4. X-ray Crystallography

The experimental X-ray crystallographic measurements details [46] are provided in the Supplementary Materials (Method S1). Crystal data of the [Cu4(DPPT)2Cl6] complex is presented in Table 4.

3.5. Hirshfeld Surface Analysis

The Crystal Explorer Ver. 3.1 program [47,48] was used to perform this analysis.

3.6. Antimicrobial Assay

The antibacterial activity was declared in Supplementary Materials (Method S2) [49].

4. Conclusions

In this work, the reaction product of the self-assembly of CuCl2.2H2O and (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine, (HDPPT) in ethanol was characterized, and its antimicrobial activity was examined. The reaction of this class of the hydrazine Schiff base ligands afforded the monomeric metal(II) complexes, unlike previous studies, an unexpected tetranuclear [Cu4(DPPT)2Cl6] complex was obtained. There are two differently coordinated Cu(II) sites having Cu(1)N2Cl3 and Cu(2)N3Cl coordination spheres adopting square pyramidal and square planar coordination geometries with some distortion, respectively. The supramolecular structure of the [Cu4(DPPT)2Cl6] complex could be described as one-dimensional hydrogen bond polymeric structure via C-H…Cl hydrogen bonds. Antimicrobial assessments for the [Cu4(DPPT)2Cl6] complex indicated promising antimicrobial activity, especially against the fungal species A. fumigatus and C. albicans as well as Gram-positive bacteria S. aureus and B. subtilis.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/inorganics11090357/s1, Figure S1: FTIR spectra of the [Cu4(DPPT)2Cl6] complex. Figure S2: FTIR spectra of the HDPPT. Method S1: Evaluation of antimicrobial activity [49]. Method S2: Evaluation of antimicrobial activity [49].

Author Contributions

Conceptualization, S.M.S. and A.E.-F.; methodology, H.H.A.-R., A.B., S.M.S., J.D.W. and A.M.Z.S.; software, H.H.A.-R., J.D.W. and A.M.Z.S.; validation, H.H.A.-R., A.B., S.A.A.-k. and S.M.S.; Crystallographer: J.D.W. and A.M.Z.S.; formal analysis, S.M.S. A.B., J.D.W., A.M.Z.S. and H.H.A.-R.; investigation, S.M.S., A.B., and S.A.A.-k.; resources, A.E.-F., A.B., and H.H.A.-R.; data curation, S.M.S., J.D.W., A.B., and A.M.Z.S.; writing—original draft preparation, S.M.S., A.B., H.H.A.-R., S.A.A.-k., J.D.W., A.M.Z.S. and A.E.-F.; writing—review and editing, S.M.S., A.B., H.H.A.-R., S.A.A.-k., A.E.-F., J.D.W. and A.M.Z.S.; visualization, S.M.S., J.D.W. and A.M.Z.S.; supervision, S.M.S. and A.E.-F.; project administration, S.M.S., A.E.-F. and H.H.A.-R.; funding acquisition, H.H.A.-R. All authors have read and agreed to the published version of the manuscript.

Funding

The Deputyship for Research and Innovation, “Ministry of Education”, King Saud University (IFKSUOR3-188-3), Saudi Arabia.

Data Availability Statement

All data generated or analyzed during this study are included in this published article.

Acknowledgments

The authors extend their appreciation to the Deputyship for Research and Innovation, “Ministry of Education” in Saudi Arabia for funding this research (IFKSUOR3-188-3).

Conflicts of Interest

The authors declare no conflict of interest.

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Inorganics 11 00357 sch001
Scheme 1. Synthesis of the previously reported metal(II) complexes with 2,4-bis(morpholin-4-yl)-6-[(E)-2-[1-(pyridin-2-yl) ethylidene]hydrazin-1-yl]-1,3,5-triazine, (DMPT).
Scheme 1. Synthesis of the previously reported metal(II) complexes with 2,4-bis(morpholin-4-yl)-6-[(E)-2-[1-(pyridin-2-yl) ethylidene]hydrazin-1-yl]-1,3,5-triazine, (DMPT).
Inorganics 11 00357 sch001
Inorganics 11 00357 sch002
Scheme 2. Synthesis of the Ni(II)-HDPPT complexes.
Scheme 2. Synthesis of the Ni(II)-HDPPT complexes.
Inorganics 11 00357 sch002
Inorganics 11 00357 sch003
Scheme 3. Synthesis of the [Cu4(DPPT)2Cl6] complex.
Scheme 3. Synthesis of the [Cu4(DPPT)2Cl6] complex.
Inorganics 11 00357 sch003
Inorganics 11 00357 g001
Figure 1. Asymmetric unit and molecular structures of [Cu4(DPPT)2Cl6]. Symmetry code #: 2-X, 1-Y, 1-Z.
Figure 1. Asymmetric unit and molecular structures of [Cu4(DPPT)2Cl6]. Symmetry code #: 2-X, 1-Y, 1-Z.
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Inorganics 11 00357 g002
Figure 2. Intermolecular contacts (A) and packing view (B) of [Cu4(DPPT)2Cl6] complex.
Figure 2. Intermolecular contacts (A) and packing view (B) of [Cu4(DPPT)2Cl6] complex.
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Inorganics 11 00357 g003
Figure 3. Hirshfeld surfaces for [Cu4(DPPT)2Cl6] complex.
Figure 3. Hirshfeld surfaces for [Cu4(DPPT)2Cl6] complex.
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Figure 4. Fingerprint plots for the important interactions in [Cu4(DPPT)2Cl6].
Figure 4. Fingerprint plots for the important interactions in [Cu4(DPPT)2Cl6].
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Inorganics 11 00357 g005
Figure 5. Intermolecular interactions in [Cu4(DPPT)2Cl6] complex.
Figure 5. Intermolecular interactions in [Cu4(DPPT)2Cl6] complex.
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Table 1. Geometric parameters (Å and °) for the coordination environment of [Cu4(DPPT)2Cl6].
Table 1. Geometric parameters (Å and °) for the coordination environment of [Cu4(DPPT)2Cl6].
BondDistanceBondDistance
Cu1-Cl1 #2.3144(5)Cu2-Cl32.2156(5)
Cu1-Cl12.2801(5)Cu2-N11.9899(16)
Cu1-Cl22.2291(5)Cu2-N91.9539(15)
Cu1-N101.9702(15)Cu2-N121.9940(15)
Cu1-N162.643(2)
BondsAngleBondsAngle
Cl1-Cu1-Cl1 #85.566(18)N1-Cu2-Cl398.78(5)
Cl2-Cu1-Cl195.05(2)N1-Cu2-N12156.68(6)
Cl2-Cu1-Cl1 #151.04(2)N9-Cu2-Cl3159.92(5)
N10-Cu1-Cl1 #92.43(5)N9-Cu2-N180.22(6)
N10-Cu1-Cl1160.21(5)N9-Cu2-N1279.38(6)
N10-Cu1-Cl296.13(5)N12-Cu2-Cl3104.26(5)
Cu1-Cl1-Cu1 #94.432(18)
# 2-X, 1-Y, 1-Z.
Table 2. The short intermolecular interactions in [Cu4(DPPT)2Cl6] complex.
Table 2. The short intermolecular interactions in [Cu4(DPPT)2Cl6] complex.
ContactDistance
N16…H20A2.572
C15…H20A2.599
C15…H42.810
Cl2…H32.513
Cl1…C53.403
H24A…H22B2.138
Table 3. Antimicrobial activities of the free ligand HDPPT a, [Cu4(DPPT)2Cl6] and Ni(II)-HDPPT complexes.
Table 3. Antimicrobial activities of the free ligand HDPPT a, [Cu4(DPPT)2Cl6] and Ni(II)-HDPPT complexes.
MicroorganismHDPPT b[Cu4(DPPT)2Cl6][Ni(HDPPT)2](NO3)2 b[Ni(HDPPT)(NO3)Cl] bControl
A. fumigatusNA c (ND) d17(78)20 (312)18 (312)17(156) e
C. albicansNA c (ND) d19(312)21 (312)19 (312)20(312) e
S. aureusNA c (ND) d26(4.8)7 (5000)8 (2500)24(9.7) f
B. subtilis10 (1250)25(9.7)19 (312)22 (78)26(4.8) f
E. coliNA c (ND) d20(78)NA b (ND) cNA b (ND) c30(4.8) f
P. vulgarisNA c (ND) d22(39)NA b (ND) cNA b (ND) c25(4.8) f
a Inhibition zone diameter; mm (MIC; μg/mL); b [41]; c NA: No activity; d ND: Not determined; e Ketoconazole and f Gentamycin.
Table 4. Crystal data for [Cu4(DPPT)2Cl6] complex.
Table 4. Crystal data for [Cu4(DPPT)2Cl6] complex.
Compound[Cu4(DPPT)2Cl6]
CCDC2287200
Empirical formulaC40H54Cl6Cu4N16
Formula weight1225.88
Temperature/K173
Crystal systemmonoclinic
Space groupP21/c
a/Å12.9169(9)
b/Å19.6681(12)
c/Å9.7335(6)
α/°90
β/°96.8998(19)
γ/°90
Volume/Å32454.9(3)
Z2
ρcalcg/cm31.658
μ/mm−12.085
F(000)1248
Crystal size/mm30.09 × 0.06 × 0.04
RadiationMo Kα (λ = 0.71075)
2Θ range for data collection/°3.176 to 50.73
Index ranges−15 ≤ h ≤ 15, −23 ≤ k ≤ 23, −11 ≤ l ≤ 11
Reflections collected26,025
Independent reflections4508 [Rint = 0.0212, Rsigma = 0.0153]
Data/restraints/parameters4508/0/299
Goodness-of-fit on F21.023
Final R indexes [I ≥ 2σ (I)]R1 = 0.0205, wR2 = 0.0506
Final R indexes [all data]R1 = 0.0261, wR2 = 0.0528
Largest diff. peak/hole/e Å−30.27/−0.22
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Al-Rasheed, H.H.; AL-khamis, S.A.; El-Faham, A.; Barakat, A.; Slawin, A.M.Z.; Woollins, J.D.; Soliman, S.M. Synthesis, X-ray Structure, Hirshfeld Surface Analysis and Antimicrobial Assessment of Tetranuclear s-Triazine Hydrazine Schiff Base Ligand. Inorganics 2023, 11, 357. https://doi.org/10.3390/inorganics11090357

AMA Style

Al-Rasheed HH, AL-khamis SA, El-Faham A, Barakat A, Slawin AMZ, Woollins JD, Soliman SM. Synthesis, X-ray Structure, Hirshfeld Surface Analysis and Antimicrobial Assessment of Tetranuclear s-Triazine Hydrazine Schiff Base Ligand. Inorganics. 2023; 11(9):357. https://doi.org/10.3390/inorganics11090357

Chicago/Turabian Style

Al-Rasheed, Hessa H., Sarah A. AL-khamis, Ayman El-Faham, Assem Barakat, Alexandra M. Z. Slawin, John Derek Woollins, and Saied M. Soliman. 2023. "Synthesis, X-ray Structure, Hirshfeld Surface Analysis and Antimicrobial Assessment of Tetranuclear s-Triazine Hydrazine Schiff Base Ligand" Inorganics 11, no. 9: 357. https://doi.org/10.3390/inorganics11090357

APA Style

Al-Rasheed, H. H., AL-khamis, S. A., El-Faham, A., Barakat, A., Slawin, A. M. Z., Woollins, J. D., & Soliman, S. M. (2023). Synthesis, X-ray Structure, Hirshfeld Surface Analysis and Antimicrobial Assessment of Tetranuclear s-Triazine Hydrazine Schiff Base Ligand. Inorganics, 11(9), 357. https://doi.org/10.3390/inorganics11090357

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