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Communication

Structural Characterized Homotrinuclear ZnII Bis(Salamo)-Based Coordination Compound: Hirshfeld Surfaces, Fluorescent and Antimicobial Properties

by
Yang Zhang
,
Ling-Zhi Liu
,
Ying-Qi Pan
and
Wen-Kui Dong
*
School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
*
Author to whom correspondence should be addressed.
Crystals 2018, 8(7), 259; https://doi.org/10.3390/cryst8070259
Submission received: 22 May 2018 / Revised: 20 June 2018 / Accepted: 20 June 2018 / Published: 22 June 2018
(This article belongs to the Special Issue Crystal Structures of Boron Compounds)
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Abstract

:
A homotrinuclear ZnII bis(salamo) coordination compound, [LZn3(OAc)2(H2O)] of a new bis(salamo)-like ligand, has been synthesized and structurally characterized using elemental analyses, IR, UV-Vis and fluorescent spectra, and Hirshfeld surface analysis. Hirshfeld surface analyses and X-ray crystallography revealed that complexation between ZnII acetate dihydrate and the ligand H4L afforded a 3:1 (ZnII:L) type coordination compound. Moreover, the X-ray crystal structure analysis demonstrated that two μ2-acetate anions bridge three ZnII atoms in a μ2-fashion forming a homo-trinuclear structure. There were two kinds of ZnII atoms coordination geometries (strongly distorted square pyramidal (Zn1) and distorted trigonal bipyramidal (Zn2 and Zn3)) in the ZnII coordination compound. In addition, a 3D supra-molecular structure was constructed by intermolecular C-H···π and π···π interactions in the ZnII coordination compound. Most importantly, the fluorescent and antimicrobial properties of H4L and its ZnII coordination compound were investigated.

Graphical Abstract

1. Introduction

In recent years, a great number of 3D metal coordination compounds with salen-like N2O2 ligands have been widely investigated [1,2,3,4,5,6,7,8]. More recently, salamo-like N2O2 chelating ligands and their analogues, using an O-alkyloxime (–CH=N–O–(CH2)n–O–N=CH–), have been explored [9,10,11,12,13,14,15]. Compared to salen-like coordination compounds, salamo-type coordination compounds are significantly more stable. The latter, salamo-like ligands, are more attractive candidates for metal-binding sites to be involved into metallohosts. Salamo-like ligands could coordinate to different transition metal ions in a tetradentate N2O2-type fashion to form stable metal coordination compounds, some of which are often as organic reaction catalysts [16], metal enzyme reaction center models [17,18], nonlinear optical and magnetic molecular materials [19,20,21,22,23,24,25,26,27], supramolecular architectures and host-guest chemistries [28,29,30,31,32,33,34], electrochemistries [35,36,37] and so on.
To utilize salamo units to control guest recognition, a better strategy distinguished from the macrocyclization has been proposed [38,39]. Thus, we designed and prepared a new C-shaped bis(salamo)-like chelating ligand that contained a O4 site besides the two N2O2 sites, to control guest binding via using the coordination-triggered conformational changes. When the ligand is metalated, our O4 oxygen atoms are located in an acyclic, C-shaped arrangement. Moreover, the guest binding could be more effective owing to the negatively charged phenolates of the metal coordination compounds having higher coordination ability to other metals than their phenol form. Interestingly, some studies have been devoted to research mono-, multi-, homo- or heteromultinuclear metal coordination compounds bearing salamo-type ligands or their derivatives [40,41].
Herein, on the basis of our previous studies [42,43,44,45,46], we have studied cooperative formation of a trinuclear ZnII bis(salamo)-like coordination compound, instead of the dinuclear bis(salamo)-like coordination compound reported before [47], via the metalation of bis(salamo)-like ligand H4L. IR, UV-Vis titration and X-ray crystallography clearly exhibited that complexation between ZnII acetate dihydrate and H4L can form a 3:1 [Zn3L]2+ coordination compound. Meanwhile, the fluorescent and antibacterial properties of H4L and its ZnII coordination compound were also studied.

2. Experimental Section

2.1. Materials and Methods

2-Hydroxy-4-methoxybenzaldehyde (99%), 1,2-dibromopropane, 1,2-dimethoxybenzene, TMEDA, n-butyllithium, boron tribromide were bought from Alfa Aesar and used without further purification. Other solvents and reagents (DMF: N,N-dimethylformamide) were analytical grade reagents from Tianjin Chemical Reagent Factory.
C, H and N analyses were gained using a GmbH VariuoEL V3.00 automatic elemental analysis instrument (Elementar, Berlin, Germany). Elemental analysis for ZnII was measured with an IRIS ER/S-WP–1 ICP atomic emission spectrometer (Elementar, Berlin, Germany). Melting points were obtained by the use of a microscopic melting point apparatus made by Beijing Taike Instrument Company Limited and were uncorrected. IR spectra (400–4000 cm−1) were recorded on a Vertex 70 FT-IR spectrophotometer (Bruker, Billerica, MA, USA), with samples prepared as KBr pellets. UV-Vis absorption spectra were recorded on a Shimadzu UV-3900 spectrometer (Shimadzu, Tokyo, Japan). 1H NMR spectra were determined by German Bruker AVANCE DRX-400/600 spectroscopy. Single crystal X-ray structure diffraction for the ZnII coordination compound was carried out a Bruker Smart Apex CCD diffractometer. Fluorescent spectra were recorded on a F-7000 FL spectrophotometer.

2.2. Synthesis of the Ligand H4L

A synthetic route to the new ligand H4L is depicted in Scheme 1. Preparations of 2,3-dihydroxybenzene-1,4-dicarbaldehyde (1) and 2-[O-(1-ethyloxyamide)] oxime-5-methoxyphenol (2) were in accordance with the literature [48,49,50,51,52]. A ethanol solution (15 mL) of 2-[O-(1-ethyloxyamide)]oxime-5-methoxyphenol (452.46 mg, 2 mmol) was added dropwise to a ethanol solution (20 mL) of 2,3-dihydroxybenzene-1,4-dicarbaldehyde (166.13 mg, 1 mmol) under 55 °C, the mixture was heated to reflux and kept refluxing for 6 h, and then faint yellow solid of the bis(salamo)-like tetraoxime ligand (H4L) was obtained. After the solution was allowed to stand overnight at room temperature, precipitates were collected on a suction filter to afford H4L. Yield: 346.20 mg (65.5%). m.p. 148–149 °C. Anal. calcd. for C28H30N4O10 (%): C, 57.73; H, 5.19; N, 9.62. Found (%): C, 58.92; H, 5.44; N, 9.47. 1H NMR (500 MHz, CDCl) δ 9.91 (s, 2H, OH), 9.66 (s, 2H, OH), 8.23 (s, 2H, CH=N), 8.18 (s, 2H, CH=N), 7.06 (s, 2H, ArH), 6.77 (s, 2H, ArH), 6.49 (s, 2H, ArH), 6.47 (dd, J = 8.5, 2.6 Hz, 2H, ArH), 4.50 (s, 4H, CH2), 4.45 (s, 4H, CH2), 3.81 (s, 6H, CH3).

2.3. Synthesis of the ZnII Coordination Compound

A solution of ZnII acetate dihydrate (6.58 mg, 0.03 mmol) in methanol (1 mL) was added dropwise to a solution of H4L (5.88 mg, 0.01 mmol) in dichloromethane (3 mL), the color of the mixture turned to yellow immediately, the proper solvent ratio (methanol:dichloromethane = 1:3) was of utmost importance. After 0.5 h of stirring, the resulting yellow solution was filtered, and then left undisturbed. When the solution was partially evaporated, several yellow block-like single crystals suitable for X-ray crystallography were gained. Yield: 54% (4.92 mg). Anal. calcd. for C32H34Zn3N4O15 (%): C, 42.20; H, 3.76; N, 6.15; Zn, 21.54. Found (%): C, 42.41; H, 3.85; N, 6.02; Zn, 21.84.

2.4. X-ray Crystallography

The single crystal of the ZnII coordination compound, with approximate dimensions of 0.38 × 0.40 × 0.48 mm was mounted on goniometer head of Bruker Smart 1000 diffractometer equipped with Apex CCD area detector. The diffraction data were collected using a graphite mono-chromated Mo Kα radiation (λ = 0.71073 Å) at 298(2) K. The structure was solved by using the program SHELXS-97 and Fourier difference techniques, and refined by full-matrix least-squares method on F2 using SHELXL-2017. The structure contained large void, and the solvent and the positive or negative ions located in the void couldn’t be identified because it was highly disordered and had so small residual peak. Therefore, SQUEEZE in PLATON program was performed to remove the highly disordered solvent and ions. (Solvent Accessible Volume = 1762.9, Electrons Found in S.A.V. = 104.2). The nonhydrogen atoms were refined anisotropically. Hydrogen atoms were added in geometrical positions. Details of the data collection and refinements of the ZnII coordination compound are given in Table 1.
Supplementary crystallographic data have been deposited at Cambridge Crystallographic Data Centre (CCDC: 890890). Copies of the data could be gained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (Telephone: +44-01223-762910; Fax: +44-1223-336033; E-mail: [email protected]). The data could be also gained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html.

3. Results and Discussion

3.1. IR Spectra

As depicted in Figure 1, the IR spectra of H4L and its ZnII coordination compound exhibited different bands in the 4000–500 cm−1 region. A typical C=N stretching band of H4L appeared at 1626 cm−1, however that of the ZnII coordination compound was observed at 1597 cm−1, indicating that the oxime nitrogen atoms are coordinated to the ZnII atoms [53,54,55,56,57].
Meanwhile, the free ligand H4L displayed a typical Ar–O stretching frequency at 1265 cm−1, while the Ar–O stretching frequency of the ZnII coordination compound was observed at 1258 cm−1. This frequency was shifted to high frequency, which can be an evidence of formation of the ZnII–O bonds between the ZnII atoms and the phenolic oxygen atoms [58,59,60].

3.2. UV-Vis Absorption Spectra

UV-Vis absorption spectra of the ligand H4L and its ZnII coordination compound were measured in 5 × 10−5 mol/L DMF solution (Figure 2).
In the UV-Vis titration experiment of the ZnII coordination compound, the spectroscopic titration clearly showed the reaction stoichiometry ratio to be 3:1. Absorption spectra of the ZnII coordination compound were clearly different from that of H4L upon complexation. The absorption maxima at ca. 278 and 313 nm were shifted bathochromically upon coordination to the ZnII atoms, and a new absorption maxima at ca. 444 nm was absent in the spectrum of the ZnII coordination compound, which should be assigned to LMCT [61,62,63,64,65].

3.3. Crystal Structure Description

From a 3:1 mixture of ZnII acetate dihydrate and the ligand H4L, a yellow crystalline coordination compound was obtained. X-ray crystallography obviously displayed that the ZnII coordination compound included one completely deprotonated ligand (L)4− unit, three ZnII atoms, two μ2-acetate ligands, and one coordinated water molecule (Figure 3).
Two of the three ZnII (Zn2 and Zn3) atoms sat in the salamo N2O2 moieties, while Zn1 was located in the central O4 site. Two oxygen (O1 and O2) atoms bridged Zn1-Zn2 and Zn1-Zn3, respectively. In addition, two µ2-acetato ligands linked Zn1 to Zn2 and Zn1 to Zn3 stabilizing the homotrinuclear structure. The central ZnII (Zn1) atom was found to have an aqua molecule. Thus, two of the three ZnII (Zn2 and Zn3) atoms possess pentacoordinate distorted trigonal bipyramidal geometries (τ = 0.8038) in which the axial positions were held by N2-O1 and N4-O2, respectively. Besides, Zn1 atom possesses a strongly distorted square pyramidal (τ = 0.3128) coordination environment where the axial position was held by the O15 atom of the aqua molecule [17,23]. Selected bond distances and angles are listed in Table 2. It can be seen from the data that the different positions of the substituents can lead to slightly different changes in the structure [11].

3.4. Supra-Molecular Interaction

As illustrated in Table 3 and Figure 4, there were four pairs of intra-molecular O15-H15B···O9, O15-H15B···O5, C10-H10A···O12 and C20-H20B···O14 hydrogen bond interactions and a pair of C-H···π inter-molecular hydrogen bonds in the ZnII coordination compound. The ZnII coordination compound molecules were inter-linked effectively via C-H···π hydrogen bonds (C19-H19B···Cg1) into a 1D supermolecular structure. Furthermore, one molecule could link four adjacent molecules into an infinite 3D net-like supramolecular structure by two pairs of intermolecular Cg1···Cg1 and Cg3···Cg3 interactions [66,67,68,69,70,71,72]. The weak hydrogen bonds existing in the ZnII coordination compound have been described in graph sets (Figure 5) [73]. Additionally, the hydrogen bonding scheme of the ZnII coordination compound is defective due to suppression of the electron density originating from solvent molecules (used SQUEEZE) and subsequent exclusion of these solvent molecules from the refinement model.

3.5. Hirshfeld Surfaces

The Hirshfeld surfaces of the ZnII coordination compound are depicted in Figure 6, exhibiting surfaces that have been mapped over dnorm and di [74,75]. The interactions between hydroxyl oxygen in the ZnII coordination compound can be seen as bright red areas in the Hirshfeld surface in Figure 7. The light red spots are owing to C–H···O interactions, and other visible spots correspond to C···H and H···H contacts on the surface. Figure 7 shows the 2D plots generated [76,77,78] which correspond to the C···H, O···H and H···H interactions from the Hirshfeld surface of the ZnII coordination compound. To provide context, the overview of the full fingerprint is depicted in grey and the blue area showing the separate contact. The proportions of O···H/H···O, C···H/H···C and H···H interactions are composed of 22.3, 12.1 and 49.7% of the all Hirshfed surfaces for each ZnII coordination compound molecule, respectively. It is because of the existence of these hydrogen bondings that the ZnII coordination compound can be stable.

3.6. Fluorescent Spectra

The fluorescence titration experiment of the ZnII coordination compound with H4L was studied. Figure 8 shows gradual changes in the fluorescence spectra of H4L upon addition of ZnII ions. The ligand exhibited an intense emission at ca. 525 nm upon excitation at 380 nm based on global maximum determined from three-dimensional fluorescence spectra, which could be attributed to intra-lignd π–π* transition [79,80,81]. Figure 8 obviously indicates that fluorescence emission of the ligand H4L was very weak, probably owing to isomerization of C=N double bond, intramolecular hydrogen bond between azomethine and hydroxyl moieties of the aromatic group. Upon incremental addition of ZnII ions to the solution of H4L, fluorescence emission intensity at 523 nm gradually increased, and this peak remained relatively constant after the addition of 3 equiv.
The ZnII coordination compound showed a strong and broad luminescence with maximum emission at ca. 523 nm upon excitation at 380 nm, which is moved bathochromically to that of H4L. Compared with the emission spectrum of H4L, enhanced fluorescent intensity of the ZnII coordination compound was observed, displaying that intra-ligand transition has been affected owing to the introduction of the ZnII atoms [82,83]. No emissions coming from ligand-to-metal/metal-to-ligand charge-transfer or metal-centered excited states are expected for the ZnII coordination compound, since ZnII is a d10 ion. Therefore, the emission of the ZnII coordination compound observed is tentatively assigned to the intra-ligand π–π* fluorescence. From the emission intensity by following the modified Benesi–Hidebrand equation, the association constant of compound was calculated as 1.59 × 104 M−1 [31,32,33,34].

3.7. Antimicobial Activities

The antimicrobial properties of H4L and its ZnII coordination compound were detected against Escherichia coli as Staphylococcus aureus and Gram-negative bacteria as Gram-positive bacteria via a punch method. The bacterial suspension was mixed in sterile LB (lysogeny broth agar) plates (2% agar), then made four holes with a hole punch, last added DMF, Zn2+, H4L, and the ZnII coordination compound into every holes. After 7 h of incubation at 37 °C, the growth-inhibitory effect was monitored and diameters of the inhibition zones were measured. The discs measuring 5 mm in diameter were dissolved in DMF. The diameters of inhibition zones of H4L and its ZnII coordination compound are given in Figure 9, the ZnII coordination compound proved more enhanced antimicrobial activities than the bis(salamo)-like tetraoxime H4L under the same concentrations.
As shown in Figure 9, the inhibitory effect of the ZnII coordination compound at different concentrations was studied, the results showed that the antibacterial effect of the ZnII coordination compound increased with increasing concentrations. The increase in the antibacterial activity of the ZnII coordination compound with increase in concentration can be explained according to the chelation theory. Chelation reduces the polarity of the metal atom mainly owing to partial sharing of positive charge of ZnII atom with donor groups and possible delocalization of π-electron within the whole chelate ring. Further, it enhances the lipophilic character of the central atom. These results are similar to earlier reports of biological activities of similar salamo-like CoII coordination compounds [84].

4. Conclusions

A newly designed symmetric bis(salamo)-like chelating tetraoxime ligand H4L, possessing a C-shaped O4 site besides the two N2O2 sites, has been synthesized, and its ZnII coordination compound [LZn3(OAc)2(H2O)] has been determined by X-ray crystallography. The UV-Vis titration experiment clearly showed the reaction stoichiometry ratio to be 3:1. In the ZnII coordination compound, Zn1 is pentacoordinate with a strongly distorted square pyramidal geometry, while Zn2 and Zn3 possess pentacoordinates with distorted trigonal bipyramidal geometries. Furthermore, the Hirshfeld surface analysis indicated that the ZnII coordination compound could be stable due to intramolecular hydrogen bonds and some weaker interactions. Fluorescence behaviors of H4L and its ZnII coordination compound were investigated, compared with the ligand H4L, the emission intensity of the ZnII coordination compound increased obviously, which indicated that the ZnII ions possess a quality of fluorescent enhancement. Antimicrobial experiments showed that the ZnII coordination compound demonstrated more enhanced antimicrobial activities than H4L under the same conditions.

Author Contributions

W.-K.D. conceived and designed the experiments; Y.Z. performed the experiments; Y.-Q.P. analyzed the data; L.-Z.L. contributed reagents/materials/analysis tools; Y.Z. wrote the paper.

Funding

This work was supported by the Program for Excellent Team of Scientific Research in Lanzhou Jiaotong University, 201706; National Natural Science Foundation of China, 21761018.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (21761018) and the Program for Excellent Team of Scientific Research in Lanzhou Jiaotong University (201706), both of which are gratefully acknowledged.

Conflicts of Interest

The authors declare no conflict of interests.

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Crystals 08 00259 sch001 550
Scheme 1. Synthesis route of H4L.
Scheme 1. Synthesis route of H4L.
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Crystals 08 00259 g001 550
Figure 1. IR spectra of the ligand H4L and its ZnII coordination compound.
Figure 1. IR spectra of the ligand H4L and its ZnII coordination compound.
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Figure 2. Absorption spectra of H4L in DMF with the increase of ZnII. Inset: the absorbance at 444 nm varied as a function of [Zn2+]/[H4L]. [H4L] = 5 × 10−5 mol/L.
Figure 2. Absorption spectra of H4L in DMF with the increase of ZnII. Inset: the absorbance at 444 nm varied as a function of [Zn2+]/[H4L]. [H4L] = 5 × 10−5 mol/L.
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Figure 3. (a) Representation of the ZnII coordination compound structure; (b) The coordination polyhedra of Zn1 and Zn2 centers.
Figure 3. (a) Representation of the ZnII coordination compound structure; (b) The coordination polyhedra of Zn1 and Zn2 centers.
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Figure 4. (a) Intra-molecular hydrogen bondings of the ZnII coordination compound unit (hydrogen atoms, except those forming hydrogen bonds, are omitted for clarity); (b) One-dimensional supra-molecular structure of the ZnII coordination compound, mediated by inter-molecular C-H···π (pink) interactions; (c) 3-D supramolecular structure of the ZnII coordination compound, mediated by intermolecular C-H···π and π···π interactions.
Figure 4. (a) Intra-molecular hydrogen bondings of the ZnII coordination compound unit (hydrogen atoms, except those forming hydrogen bonds, are omitted for clarity); (b) One-dimensional supra-molecular structure of the ZnII coordination compound, mediated by inter-molecular C-H···π (pink) interactions; (c) 3-D supramolecular structure of the ZnII coordination compound, mediated by intermolecular C-H···π and π···π interactions.
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Figure 5. (a) Graph set assignments for the ZnII coordination compound; (b) Partial enlarged drawing of hydrogen bonds.
Figure 5. (a) Graph set assignments for the ZnII coordination compound; (b) Partial enlarged drawing of hydrogen bonds.
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Figure 6. Hirshfeld surfaces mapped with (a) dnorm and (b) di of the ZnII coordination compound. The surfaces are depicted as transparent to allow visualization of the molecule structure.
Figure 6. Hirshfeld surfaces mapped with (a) dnorm and (b) di of the ZnII coordination compound. The surfaces are depicted as transparent to allow visualization of the molecule structure.
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Figure 7. Fingerprint plot of the ZnII coordination compound: full and resolved into full and resolved into O···H, C···H and H···H contacts exhibiting the percentages of contacts contributed to the total Hirshfeld surface area of the ZnII coordination compound molecule.
Figure 7. Fingerprint plot of the ZnII coordination compound: full and resolved into full and resolved into O···H, C···H and H···H contacts exhibiting the percentages of contacts contributed to the total Hirshfeld surface area of the ZnII coordination compound molecule.
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Figure 8. (a) Fluorescence spectrum changes of the H4L solution (c = 5 × 10−5 mol/L) upon addition of different amounts of ZnII ions (0–3.0 equiv) in dilute dichloromethane:methanol (v:v = 1:1) solutions at room temperature; (b) The linear relationship between fluorescence intensity and the concentrations of ZnII ions. (λex = 380 nm, λem = 523 nm).
Figure 8. (a) Fluorescence spectrum changes of the H4L solution (c = 5 × 10−5 mol/L) upon addition of different amounts of ZnII ions (0–3.0 equiv) in dilute dichloromethane:methanol (v:v = 1:1) solutions at room temperature; (b) The linear relationship between fluorescence intensity and the concentrations of ZnII ions. (λex = 380 nm, λem = 523 nm).
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Figure 9. (a) The diameters of inhibition zones of E. coli and S. aureus at different concentrations; (b) the diameter of inhibition zones of E. coli and S. aureus in different concentrations.
Figure 9. (a) The diameters of inhibition zones of E. coli and S. aureus at different concentrations; (b) the diameter of inhibition zones of E. coli and S. aureus in different concentrations.
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Table
Table 1. Crystallographic data and collection parameters for the ZnII coordination compound.
Table 1. Crystallographic data and collection parameters for the ZnII coordination compound.
Empirical FormulaC32H34Zn3N4O15
Formula weight910.74
Temperature, K298(2)
Wavelength, Å0.71073
Crystal systemMonoclinic
Space groupC 2/c
Cell dimensions, (Å, deg)a = 26.702(2) b = 21.6859(19), c = 14.8470(13), β = 101.253(2)
Volume, Å38432.0(13)
Z8
Density (calculated), mg/m31.435
Absorption coefficient, mm−11.759
F(000)3712.0
Index ranges−28≤ h≤ 31, −22 ≤ k ≤25, −17≤ l ≤16
Reflections collected20,924/7426 [R(int) = 0.0496]
Independent reflections5335
Data/restraints/parameters 7426/36/514
Goodness of fit indicator0.944
R [I > 2σ(I)] R1 = 0.0366, wR2 = 0.0903
Largest diff. peak and hole, e∙Å−30.357 and −0.382
R1 = Σ‖Fo| − |Fc‖/Σ|Fo|; wR2 = [Σw(Fo2 − Fc2)2/Σw(Fo2)2]1/2, w = [σ2(Fo2) + (0.0784P)2 + 1.3233P]−1, where P = (Fo2 + 2Fc2)/3; GOF = [Σw(Fo2 − Fc2)2/nobs-nparam)]1/2.
Table
Table 2. Selected bond lengths (Å) and angles (°) for the ZnII coordination compound.
Table 2. Selected bond lengths (Å) and angles (°) for the ZnII coordination compound.
BondLengthsBondLengthsBondLengths
Zn1-O111.975(3)Zn1-O131.998(3)Zn1-O152.021(3)
Zn1-O22.042(2)Zn1-O12.079(2)Zn2-O51.962(2)
Zn2-O121.985(3)Zn2-O12.052(2)Zn2-N12.091(3)
Zn2-N22.135(3)Zn3-O91.959(3)Zn3-O141.971(3)
Zn3-O22.057(2)Zn3-N42.104(3)Zn3-N32.150(3)
BondAnglesBondAnglesBondAngles
O11-Zn1-O1389.62(13)O11-Zn1-O15114.09(13)O13-Zn1-O1599.82(11)
O11-Zn1-O2145.43(15)O13-Zn1-O293.15(10)O15-Zn1-O299.38(9)
O11-Zn1-O188.93(11)O13-Zn1-O1164.20(13)O15-Zn1-O195.13(10)
O2-Zn1-O179.31(9)O5-Zn2-O12114.15(11)O5-Zn2-O192.43(9)
O12-Zn2-O190.61(10)O5-Zn2-N1126.79(11)O12-Zn2-N1118.97(11)
O1-Zn2-N184.29(10)O5-Zn2-N287.16(10)O12-Zn2-N294.10(11)
O1-Zn2-N2175.02(10)N1-Zn2-N291.98(11)O9-Zn3-O14112.13(11)
O9-Zn3-O293.72(10)O14-Zn3-O295.00(10)O9-Zn3-N488.47(11)
O14-Zn3-N496.81(11)O9-Zn3-N3121.50(11)O2-Zn3-N381.51(10)
O2-Zn3-N4166.17(11)O14-Zn3-N3126.37(11)N4-Zn3-N385.70(12)
Table
Table 3. Hydrogen bonding and π···π stacking interactions [Å, °] for the ZnII coordination compound.
Table 3. Hydrogen bonding and π···π stacking interactions [Å, °] for the ZnII coordination compound.
D–H···Ad(D–H)d(H–A)d(D–A)∠D–X–ASymmetry Code
O15–H15B···O90.851.842.675(4)168
O15–H15C···O50.851.802.625(4)162
C10–H10A···O120.972.493.367(5)150
C20–H20B···O140.972.423.296(6)150
C19-H19B···Cg10.972.843.601(5)1361/2 − X, 1/2 + Y, 1/2 − Z
Cg1···Cg1 4.372 1/2 − X, 1/2 − Y, 1 − Z
Cg3···Cg3 4.541 1/2 − X, 1/2 − Y, −Z
Note: Cg1 is the centroids for benzene ring C12–C17, Cg3 is the centroids for benzene ring C22–C27.

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Zhang, Y.; Liu, L.-Z.; Pan, Y.-Q.; Dong, W.-K. Structural Characterized Homotrinuclear ZnII Bis(Salamo)-Based Coordination Compound: Hirshfeld Surfaces, Fluorescent and Antimicobial Properties. Crystals 2018, 8, 259. https://doi.org/10.3390/cryst8070259

AMA Style

Zhang Y, Liu L-Z, Pan Y-Q, Dong W-K. Structural Characterized Homotrinuclear ZnII Bis(Salamo)-Based Coordination Compound: Hirshfeld Surfaces, Fluorescent and Antimicobial Properties. Crystals. 2018; 8(7):259. https://doi.org/10.3390/cryst8070259

Chicago/Turabian Style

Zhang, Yang, Ling-Zhi Liu, Ying-Qi Pan, and Wen-Kui Dong. 2018. "Structural Characterized Homotrinuclear ZnII Bis(Salamo)-Based Coordination Compound: Hirshfeld Surfaces, Fluorescent and Antimicobial Properties" Crystals 8, no. 7: 259. https://doi.org/10.3390/cryst8070259

APA Style

Zhang, Y., Liu, L. -Z., Pan, Y. -Q., & Dong, W. -K. (2018). Structural Characterized Homotrinuclear ZnII Bis(Salamo)-Based Coordination Compound: Hirshfeld Surfaces, Fluorescent and Antimicobial Properties. Crystals, 8(7), 259. https://doi.org/10.3390/cryst8070259

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