Next Article in Journal
Multifunctional Optical Crystals for All-Solid-State Raman Lasers
Previous Article in Journal
Role of Halogen Substituents on Halogen Bonding in 4,5-DiBromohexahydro-3a,6-Epoxyisoindol-1(4H)-ones
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Crystals
Volume 11
Issue 2
10.3390/cryst11020113
crystals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex

by
Yun-Dong Peng
,
Ruo-Yu Li
,
Peng Li
and
Yin-Xia Sun
*
School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
*
Author to whom correspondence should be addressed.
Crystals 2021, 11(2), 113; https://doi.org/10.3390/cryst11020113
Submission received: 17 January 2021 / Accepted: 22 January 2021 / Published: 26 January 2021
(This article belongs to the Section Inorganic Crystalline Materials)
Browse Figures
Review Reports Versions Notes

Abstract

:
A rare homotrinuclear CuII salamo-based complex [Cu3(L)2(μ-OAc)2(H2O)2]·2CHCl3·5H2O was prepared through the reaction of a non-symmetric salamo-based ligand H2L and Cu(OAc)2·H2O, and validated by elemental analyses, UV-Visible absorption, fluorescence and infrared spectra, molecular simulation and single-crystal X-ray analysis techniques. It is shown that three CuII atoms and two wholly deprotonated ligand (L)2− moieties form together a trinuclear 3:2 (M:L) complex with two coordination water molecules and two bi-dentate briging μ-acetate groups (μ-OAc−). Besides, the Hirshfeld surface analysis of the CuII complex was investigated. Compared with other ligands, the fluorescent strength of the CuII complex was evidently lowered, showing that the CuII ions possess fluorescent quenching effect.

1. Introduction

Both the salen-based ligands and their derivatives have shown strong development potential in the research of materials chemistry, coordination chemistry, and environmental monitoring for decades because of their good application prospects in organic catalytic synthesis, molecular magnetic properties, and luminescent properties [1,2,3,4,5], which, owing to their N2O2-donor structure, usually have excellent coordination ability to transition metal ions for various structural novel complexes (derivatives) [6,7,8,9,10,11].
The salamo-based ligands with strong stability and multifunctional chelating ability have also been studied as a significant class of organic compounds containing N2O2-donor groups [12,13,14,15,16,17,18]. When compared with salen-based ligands, the salamo-based compounds and their complexes have been applied to ion recognition [19,20], optics [21], electrochemistry [22], magnetism [23,24], biochemistry [25,26], catalysis [27,28], supermolecular construction [29,30], and other fields [31,32,33,34,35,36,37,38], which are expected to give the salamo-based ligands and their derivatives good development potential to become one of the new research hotspots of coordination chemistry.
The fluorescence on-off phenomenon in the coordination reaction of the salamo-based ligands and CuII ions can be used to identify and detect CuII ions in the environment [39,40,41,42]. According to a large amount of preliminary research works [43,44,45,46,47,48,49], here, a non-symmetrical salamo-derived compound H2L was prepared, several single crystals of its CuII complex were obtained by natural evaporation method in chloroform/ethanol mixed solvent at room temperature in about one month, and the structures and properties of H2L and its CuII complex were further characterized by various modern analytical techniques.

2. Experimental Section

2.1. Materials and Instruments

All chemical solvents and raw materials were acquired from mercantile sources and could be used directly. Elemental analysis of CuII was tested via IRISER/S-WP-1 ICP atomic emission spectrometer (Elementar, Berlin, Germany), and associated elemental analyses for carbon, hydrogen, and nitrogen were carried out by GmbH VariuoEL V3.00 automatic elemental analysis instrument (Elementar, Berlin, Germany).The study of IR spectra were recorded according to a Bruker VERTEX70 FT-IR spectrophotometer, with samples prepared as CsI (100–500 cm−1) and KBr (400–4000 cm−1) pellets (Bruker AVANCE, Billerica, MA, USA). The UV-Visible spectra were acquired from a Shimadzu UV-3900 spectrometer (Shimadzu, Tokyo, Japan). The 1H NMR spectra were tested via German Bruker AVANCE DRX-400/600 spectrometer (Bruker AVANCE, Billerica, MA, USA). Fluorescent spectra of H2L and its CuII complex were conducted from an F-7000FL spectrophotometer (Hitachi, Tokyo, Japan). The structure of X-ray single-crystal determination was also carried out on a SuperNova Dual (Cu at zero) four-circle diffractometer. Finally, mass spectrum was recorded using the Bruker Daltonics Esquire 6000 mass spectrometer.

2.2. Preparation of H2L

H2L was obtained by condensation reactions and the process involving nucleophilic addition and elimination, and the synthetic route was depicted in Scheme 1.
The synthesis procedure of the non-symmetric salamo-derived ligand (H2L) could be found in Scheme 1. 2-[O-(1-ethyloxyamide)]oxime-2-naphthol and 1,2-bis(aminooxy)ethane were synthesized on the basis of similar approaches [20,50].
Salicylaldehyde (244.1 mg, 2.0 mmol) in ethanol (50 mL) was slowly dropped to 2-[O-(1-ethyloxyamide)] oxime-2-naphthol (492.2 mg, 2.0 mmol) in ethanol (30 mL). The solution was stirred at 55 °C for 6 h, cooled to room temperature, and the precipitate was purified with recrystallization from n-hexane to obtain the product H2L. Yield: 551.7 mg, 78.7%. m.p.: 136~138 °C. 1H NMR (500 MHz, DMSO-d6) δ 10.68 (s, 1H, ArH), 9.97 (s, 1H, ArH), 9.02 (s, 1H, CH=N), 8.65 (d, J = 8.6 Hz, 1H, CH), 8.47 (s, 1H, CH=N), 7.88 (d, J = 8.9 Hz, 1H, CH), 7.84 (d, J = 7.8 Hz, 1H, CH), 7.56 (d, J = 7.8 Hz, 1H, CH), 7.54–7.48 (m, 1H, CH), 7.39–7.33 (m, 1H, CH), 7.28–7.23 (m, 1H, CH), 7.21 (d, J = 8.9 Hz, 1H, CH), 6.90 (d, J = 9.1 Hz, 1H, CH), 6.85 (t, J = 7.9 Hz, 1H, CH), 4.54–4.42 (m, 4H,CH2). (Figure S1) Anal. Calcd for C20H18N2O4 (%): C 68.56; H 5.18; N 8.00. Found: C 68.74; H 5.15; N 7.93. UV−Visible (CH3OH), λmax (nm) (εmax, L⋅mol−1⋅cm−1): 301 (5.61 × 104), 312 (6.80 × 104), 340 (3.11 × 104), 355 (3.13 × 104).

2.3. Preparation of the CuII Complex

The CuII complex was obtained by mixing H2L (3.5 mg, 0.01 mmol) in chloroform (3 mL) with Cu(OAc)2·H2O (3.0 mg, 0.015 mmol) in ethanol (5 mL) at room temperature, and the mixed solution color turned to brownish green. The brownish green mixture was filtered, and several single crystals were acquired via natural evaporation method. About one week later, several brownish green block-like single crystals were obtained. Yield: 42.3% (2.90 mg). ESI-FTMS (Figure S2) m/z = 825.087 [Cu2L2+H]+, calc. 824.840; m/z = 532.982 [Cu(H2L)(OAc)2+H]+, calc. 532.920; m/z = 414.046 [Cu(HL)+H]+, calc. 413.920; m/z = 412.048. [Cu(HL)]+, calc. 412.920. Anal. Calcd for [Cu3(L)2(μ-OAc)2(H2O)2]·2CHCl3·5H2O (C46H54Cl6Cu3N4O19) (%): C 40.32; H 3.97; N 4.09; Cu 13.91. Found: C 41.09; H 3.86; N 4.26; Cu 14.25. UV−Visible (CH3OH), λmax (nm) (εmax, L⋅mol−1⋅cm−1): 314 (7.32 × 104), 369 (3.86 × 104), 401 (2.67 × 104).

2.4. Determination of Single-Crystal Structure of the CuII Complex

The single-crystal of the CuII complex with approximate dimensions of 0.22 × 0.2 × 0.18 mm3 was mounted on goniometer head of a SuperNova Dual (Cu at zero) diffractometer. The diffraction data were collected using a graphite mono-chromated Mo-Kα radiation (λ = 0.71073 Å) at 173(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 nonhydrogen atoms were refined anisotropically. The hydrogen and carbon atoms of the molecule (C8, H8A and H8B sites occupancy disorder 0.450, and C9′, H9′A and H9′B sites occupancy disoeder 0.550) are disordered unequally. The crystallographic parameters of the CuII complex are listed in Table 1.

3. Results and Discussion

3.1. IR Spectra

The main infrared spectra of H2L and its CuII complex are given in Table 2. The spectrum of H2L showed a strong stretching vibration band at about 3216 cm−1 which indicates the presence of multi molecular association and intramolecular hydrogen bonds (νO-H). However, this peak disappeared in the CuII complex, reflecting that the O−H groups of H2L are wholly deprotonated [51]. A new O−H stretching vibration peak in the CuII complex was observed at approximately 3420 cm−1 that belongs to the coordination water molecules [52]. The stretching vibration bands at 1609 (νC=N) and 1261 cm−1 (νAr-O) of the ligand H2L were shifted to the low frequencies via ca. 6 and 11 cm-1 upon coordination [53]. Besides, the spectrum of the CuII complex showed absorption bands at ca. 3425, 1606, and 547 cm−1 which could be assigned to the coordination water molecules, as is substantiated by the results of elemental analyses and the crystal structure [52]. At the same time, the far-infrared spectrum of the CuII complex was also obtained in the range of the 100~500 cm−1 region so that a distinction could be made between frequencies of the Cu-O and Cu-N bonds, and new peaks of the CuII complexes were found at ca. 455 and 512 cm−1 [54], respectively. These results support the proposal that strong binding participations have occurred in the CuII complex [39].

3.2. UV-Visible Spectra

The UV-Visible spectra of the ligand H2L and its CuII complex were tested in methanol solution (1.0 × 10−5 mol/L) at room temperature.
As depicted in Figure 1, the spectrum of H2L showed four relatively strong absorption peaks at approximately 301, 312, 340, and 355 nm, the absorption peak at 301 nm belongs to the π–π* transitions of the benzene rings [55]. The peaks at 312, 340, and 355 nm can be attributed to the π-π* transitions of the C=N bonds of intra-ligand [56]. The absorption peak of the CuII complex appeared at about 314 nm; this peak could be appointed to π-π* transitions of the C=N bonds, indicating that coordination reaction occurred between H2L and the CuII atoms [56,57]. Simultaneously, two new peaks were found at about 369 and 401 nm, which could be appointed to L→M charge-transfer transitions (LMCT). This is characteristic of the metal N2O2-donor complexes [57].
In order to explain the coordination of the ligand H2L to CuII ions, the UV-Vis absorption titration experiment was also performed (Figure 2). When the centration of CuII ions were added gradually, a new absorption peak appeared between 345 nm and 460 nm, which inferred that the ligand H2L and CuII ions coordinate in 1:1.5 ratio to produce a new L-CuII complex.

3.3. Structure Analysis of the CuII Complex

The CuII complex crystallizes in the triclinic system, space group I41/a. The bond lengths and angles are listed in Table 3. X-ray single-crystal data showed that three CuII atoms and two completely deprotonated ligand (L)2− moieties produce together a rare homotrinuclear 3:2 (M:L) complex with two coordination water molecules and two bi-dentate briging μ-acetate groups (μ-OAc−). This structure differs from the usual mono-nuclear CuII salamo-based complexes [58]. The six-coordinated terminal CuII (Cu1) atom is sited at the N2O2 cavity containing two phenolic oxygen (O4 and O1) and oxime nitrogen (N2 and N1) atoms in the ligand (L)2− moiety, which forms a basic equatorial plane, and bound to the other two oxygen (O7 and O5) atoms coming from one coordination water molecule and the μ-OAc− group, respectively, at the end, forming a slightly distorted octahedral geometry. The central CuII (Cu2) is located on a crystallographic center of inversion. More interestingly, the six-coordinated central CuII (Cu2) atom is an octahedron, the Cu2 atom is surrounded by O6 atoms, which involved two completely deprotonated ligand (L)2− moieties and two bridged acetate (μ-OAc−) groups (Figure 3a,b). The hydrogen bond data are summarized in Table 4.
In addition, there are three couple of intra-molecular hydrogen bondings (C9′-H9′A⋯O5, O7-H7A⋯N2 and O7-H7B⋯O4) in the CuII complex [59], as depicted in Figure 4.

3.4. Molecular Simulation Calculation of H2L and Its CuII Complex

In order to better investigate the structures of H2L and its CuII complex, the DMol3 module of MS (Materials Studio) software was used to optimize and simulate the molecules of H2L and its CuII complex [60].
The method of structural optimization (property calculation) is GGA, BP (PBE) with the base set DND (DNP), the solvent model (ethanol), the optimization precision set medium, and smooth thermal smearing to speed up the convergence of structural optimization. The molecule energies and frontier molecular orbital energies of H2L and its CuII complex are shown in Table 5. For H2L, it could be found that the calculated energy gap between the LUMO and HOMO of the CuII complex (0.984 ev) is lower than that of H2L (1.803 ev) (Figure 5). According to the frontier orbital theory, the photoinduced electron transfer (PET) may be caused by fluorescence quenching [24].

3.5. Fluorescence Spectra

The fluorescent properties of the ligand and its CuII complex were invested in 1 × 10−5 M ethanol solution at 349 nm excitation wavelength. Corresponding spectra are depicted in Figure 6.
The CuII complex underwent fluorescence quenching at 434 nm and the emission peak is red-shifted, this can be appointed to LMCT [61]. Owing to the H2L molecule’s non-bonding pairs on the oxime N atoms where there is a PET (photoinduced electron transfer) process from the N atom to the benzene ring. Due to the existence of CuII ions, the fluorescent strength of the system is quenched. This result reflects that CuII ions interact with the system effectually and have the PET (photoinduced electron transfer) effect, which attenuates the fluorescent strength [62].

3.6. Hirshfeld Surface Analysis

Hirshfeld surface supplies a 3-D figure of inter-molecular inter-actions in the CuII complex (Figure 7) [63], which could clearly indicate that the surfaces have been mapped over dnorm and the corresponding location in shape index exists in the complementary region of red concave surface surrounded by receptors and the blue convex surface surrounding receptors, further proving that such hydrogen bonding exists. The large and deep red spots on the three-dimensional (3D) Hirshfeld surfaces indicate close-contact interactions, which are mainly responsible for the corresponding hydrogen bond contacts. As for the large amount of white region in the dnorm surfaces, it is suggested that there is a weaker and farther contact between molecules, rather than hydrogen bonding. The red zone expresses the O–H between the H and O atoms in the CuII complex. In the interaction intensity figure, the heavier the red area color is, the stronger O–H inter-actions are. As illustrated, the shallower areas mostly represent the spread of influences such as H–H and C–H. As illustrated in the figure, the spread of the approximated hydrogen bonds among the CuII complex could also be analyzed. This is conducive of investigating inherent elements of the steady existence among the CuII complex [64].
In addition, the proportion of C–H/H–C, O–H/H–O, and H–H in the CuII complex can also be acquired by Hirshfeld surfaces analyses [65,66,67,68,69]. Here, we theoretically calculated the percentages of connects devoted to the total Hirshfeld surface region of the CuII complex.
As shown in Figure 8, in this 2-D Hirshfeld surface figure, the blue area expresses the distribution of various interactions for the whole CuII complex. The associated ratios of O–H/H–O, C-H/H-C and H–H/H–H in the surface of Hirshfeld were computed as 8.4%, 18.2%, and 70.2%, respectively.

4. Conclusions

In summary, we prepared the non-symmetric salamo-derived ligand H2L and several single crystals of its CuII complex. [Cu3(L)2(μ-OAc)2(H2O)2]·2CHCl3·5H2O were cultured by slow evaporation method and various test methods were characterized. Interestingly, the single crystal structure analysis showed that H2L and CuII ions form a symmetric trinuclear CuII complex. The UV-Visible titration clearly showed that the radio of H2L to CuII ions has a 2:3 stoichiometry. Hirshfeld surface analysis indicated that the CuII complex could be stable due to intra-molecular hydrogen bond interactions.

Supplementary Materials

The following are available online at https://www.mdpi.com/2073-4352/11/2/113/s1, Figure S1: 1H NMR spectrum of H2L. Figure S2: Mass spectrum of the CuII complex.

Author Contributions

Y.-D.P. and R.-Y.L. performed the experiments; Y.-X.S. conceived and designed the experiments, and contributed reagents/materials/analysis tools; P.L. analyzed the data. Y.-D.P. and R.-Y.L. wrote the paper. All authors have read and agreed to the published version of the manuscript.

Funding

“This research was funded by National Natural Science Foundation of China, grant number 21761018” and “The APC was funded by Lanzhou Jiaotong University”. The standard spelling of funding agency names at https://search.crossref.org/funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

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), two of which are gratefully acknowledged.

Conflicts of Interest

The authors declear no competing financial interest.

References

  1. Wu, H.L.; Pan, G.L.; Bai, Y.C.; Wang, H.; Kong, J.; Shi, F.; Zhang, Y.H.; Wang, X.L. Preparation, structure, DNA-binding properties, and antioxidant activities of a homodinuclear erbium(III) complex with a pentadentate Schiff base ligand. J. Chem. Res. 2014, 38, 211–217. [Google Scholar] [CrossRef]
  2. Song, X.Q.; Liu, P.P.; Liu, Y.A.; Zhou, J.J.; Wang, X.L. Two dodecanuclear heterometallic [Zn6Ln6] clusters constructed by a multidentate salicylamide salen-like ligand: Synthesis, structure, luminescence and magnetic properties. Dalton Trans. 2016, 45, 8154–8163. [Google Scholar] [CrossRef] [PubMed]
  3. Liu, P.P.; Wang, C.Y.; Zhang, M.; Song, X.Q. Pentanuclear sandwich-type ZnII–LnIII clusters based on a new salen-like salicylamide ligand: Structure, near-infrared emission and magnetic properties. Polyhedron 2017, 129, 133–140. [Google Scholar] [CrossRef]
  4. Wu, H.L.; Wang, C.P.; Wang, F.; Peng, H.P.; Zhang, H.; Bai, Y.C. A newmanganese(III) complex from bis(5-methylsalicylaldehyde)-3-oxapentane-1,5-diamine: Synthesis, characterization, antioxidant activity and luminescence. J. Chin. Chem. Soc. 2015, 62, 1028–1034. [Google Scholar] [CrossRef]
  5. Zhou, J.J.; Song, X.Q.; Liu, Y.A.; Wang, X.L. Substituent-tuned structure and luminescence sensitizing towards Al3+ based on phenoxy bridged dinuclear EuIII complexes. RSC Adv. 2017, 7, 25549–25559. [Google Scholar] [CrossRef] [Green Version]
  6. Sun, Y.X.; Pan, Y.Q.; Xu, X.; Zhang, Y. Unprecedented dinuclear CuII N,O-donor complex: Synthesis, structural characterization, fluorescence property, and Hirshfeld analysis. Crystals 2019, 9, 607. [Google Scholar] [CrossRef] [Green Version]
  7. Cui, Y.F.; Liu, C.; Zhang, Y.; Zhang, Y. Newly designed and synthesized heterobimetallic [CuII–DyIII] salamo-like complex: Structural characterization, DFT calculation, and fluorescent property. Inorg. Nano-Met. Chem. 2021, 51, 288–295. [Google Scholar] [CrossRef]
  8. Peng, Y.D.; Zhang, Y.; Jiang, Y.L.; Ren, Z.L.; Wang, F.; Wang, L. An unsymmetric salamo-like chemosensor for fuorescent recognition of Zn2+. J. Fluores. 2020, 30, 1049–1061. [Google Scholar] [CrossRef]
  9. Mu, H.R.; An, X.X.; Liu, C.; Zhang, Y.; Dong, W.K. Structurally characterized self-assembled heterobimetallic Ni(II)-Eu(III)-salamo-bipyridine coordination polymer: Synthesis, photophysical and antimicrobial properties. J. Struct. Chem. 2020, 61, 1155–1166. [Google Scholar] [CrossRef]
  10. Cui, Y.F.; Zhang, Y.; Xie, K.F.; Dong, W.K. A newly synthesized heterobimetallic NiII-GdIII salamo-bdc-based coordination polymer: Structural characterization, DFT calculation, fluorescent and antibacterial properties. Crystals 2019, 9, 596. [Google Scholar] [CrossRef] [Green Version]
  11. Zhang, Y.; Yu, M.; Pan, Y.Q.; Zhang, Y.; Xu, L.; Dong, X.Y. Three rare heteromultinuclear 3d-4f salamo-like complexes constructed from auxiliary ligand 4,4′-bipy: Syntheses, structural characterizations, fluorescence and antimicrobial properties. Appl. Organomet. Chem. 2020, 34, e5442. [Google Scholar] [CrossRef]
  12. Zhang, L.W.; Zhang, Y.; Cui, Y.F.; Yu, M.; Dong, W.K. Heterobimetallic [NiII LnIII] (Ln = Sm and Tb) N2O4-donor coordination polymers: Syntheses, crystal structures and fluorescence properties. Inorg. Chim. Acta 2020, 506, 119534. [Google Scholar] [CrossRef]
  13. Akine, S.; Sairenji, S.; Taniguchi, T.; Nabeshima, T. Stepwise helicity inversions by multisequential metal exchange. J. Am. Chem. Soc. 2013, 135, 12948–12951. [Google Scholar] [CrossRef] [PubMed]
  14. Chang, J.; Zhang, S.Z.; Wu, Y.; Zhang, H.J.; Sun, Y.X. Three supramolecular trinuclear nickel(II) complexes based on Salamo-type chelating ligand: Syntheses, crystal structures, solvent effect, Hirshfeld surface analysis and DFT calculation. Transit. Met. Chem. 2020, 45, 279–293. [Google Scholar] [CrossRef]
  15. Novozhilova, M.V.; Smirnova, E.A.; Polozhentseva, J.A.; Danilova, J.A.; Chepurnaya, I.A.; Karushev, M.P.; Malev, V.V.; Timonov, A.M. Multielectron redox processes in polymeric cobalt complexes with N2O2 Schiff base ligands. Electrochim. Acta 2018, 282, 105–115. [Google Scholar] [CrossRef]
  16. Bian, R.N.; Wang, J.F.; Li, Y.J.; Zhang, Y.; Dong, W.K. Fluorescent chemical sensor based on double N2O2 cavities for continuous recognition of Cu2+ and Al3+. J. Photochem. Photobiol. A 2020, 400, 112829. [Google Scholar] [CrossRef]
  17. Kang, Q.P.; Li, X.Y.; Wang, L.; Zhang, Y.; Dong, W.K. Containing-PMBP N2O2-donors transition metal(II) complexes: Synthesis, crystal structure, Hirshfeld surface analyses and fluorescence properties. Appl. Organomet. Chem. 2019, 33, e5013. [Google Scholar] [CrossRef]
  18. Wang, J.F.; Li, P.; Li, L.L.; Dong, W.K. A perspective on molecular structure and experimental-computational characterization of a novel Cd(II) pyridine-terminal salamo-like coordination polymer. Russ. J. Gen. Chem. 2020, 10, 1997–2003. [Google Scholar] [CrossRef]
  19. Wei, Z.L.; Wang, L.; Guo, S.Z.; Zhang, Y.; Dong, W.K. A high-efficiency salamo-based copper(II) complex double-channel fluorescent probe. RSC Adv. 2019, 9, 41298. [Google Scholar] [CrossRef] [Green Version]
  20. Pan, Y.Q.; Xu, X.; Zhang, Y.; Zhang, Y.; Dong, W.K. A highly sensitive and selective bis(salamo)-type fluorescent chemosensor for identification of Cu2+ and the continuous recognition of S2−, Arginine and Lysine. Spectrochim. Acta A 2020, 229, 117927. [Google Scholar] [CrossRef]
  21. Akine, S.; Morita, Y.; Utsuno, F.; Nabeshima, T. Multiple folding structures mediated by metal coordination of acyclic multidentate ligand. Inorg. Chem. 2009, 48, 10670–10678. [Google Scholar] [CrossRef] [PubMed]
  22. Liu, C.; An, X.X.; Cui, Y.F.; Xie, K.F.; Dong, W.K. Novel structurally characterized hetero-bimetallic [Zn(II)2M(II)] (M = Ca and Sr) bis(salamo)-type complexes: DFT calculation, Hirshfeld analyses, antimicrobial and fluorescent properties. Appl. Organomet. Chem. 2020, 34, e5272. [Google Scholar] [CrossRef]
  23. Akine, S.; Dong, W.K.; Nabeshima, T. Octanuclear zinc(II) and cobalt(II) clusters produced by cooperative tetrameric assembling of oxime chelate ligands. Inorg. Chem. 2006, 45, 4677–4684. [Google Scholar] [CrossRef] [PubMed]
  24. Liu, L.Z.; Wang, L.; Yu, M.; Zhao, Q.; Zhang, Y.; Sun, Y.X.; Dong, W.K. A highly sensitive and selective fluorescent “off-on-off” relay chemosensor based on a new bis(salamo)-type tetraoxime for detecting Zn2+ and CN−. Spectrochim. Acta A 2019, 222, 117209. [Google Scholar] [CrossRef] [PubMed]
  25. Colinas, I.R.; Rojas-Andrade, M.D.; Chakraborty, I.; Oliver, S.R.J. Two structurally diverse Zn-based coordination polymers with excellent antibacterial activity. CrystEngComm 2018, 20, 3353–3362. [Google Scholar] [CrossRef]
  26. Lu, X.Y.; Ye, J.W.; Zhang, D.K.; Xie, R.X.; Bogale, R.F.; Sun, Y.; Zhao, L.M.; Zhao, Q.; Ning, G.L. Silver carboxylate metal–organic frameworks with highly antibacterial activity and biocompatibility. J. Inorg. Biochem. 2013, 138, 114–121. [Google Scholar] [CrossRef]
  27. Li, X.Y.; Kang, Q.P.; Liu, C.; Zhang, Y.; Dong, W.K. Structurally characterized homo-trinuclear ZnII and hetero-pentanuclear [ZnII4LnIII] complexes constructed from an octadentate bis(salamo)-based ligand: Hirshfeld surfaces, fluorescence and catalytic properties. New J. Chem. 2019, 43, 4605–4619. [Google Scholar] [CrossRef]
  28. Haak, R.M.; Decortes, A.; Escudero, E.C.; Belmonte, M.M.; Martin, E.; Buchholz, J.B.; Kleij, A.W. Shape-persistent octanuclear zinc salen clusters: Synthesis, characterization, and catalysis. Inorg. Chem. 2011, 50, 7934–7936. [Google Scholar] [CrossRef]
  29. Yu, M.; Zhang, Y.; Pan, Y.Q.; Wang, L. Two novel copper(II) salamo-based complexes: Syntheses, x-ray crystal structures, spectroscopic properties and Hirshfeld surfaces analyses. Inorg. Chim. Acta 2020, 509, 119701. [Google Scholar] [CrossRef]
  30. An, X.X.; Chen, Z.Z.; Mu, H.R.; Zhao, L. Investigating into crystal structures and supramolecular architectures of four newly synthesized hetero-octanuclear [CuII4–LnIII4] (Ln = Sm, Eu, Tb and Dy) complexes produced by a hexadentate bisoxime chelate ligand. Inorg. Chim. Acta 2020, 511, 119823. [Google Scholar] [CrossRef]
  31. Wang, J.F.; Bian, R.N.; Feng, T.; Xie, K.F.; Wang, L.; Ding, Y.J. A highly sensitive dual-channel chemical sensor for selective identification of B4O72−. Microchem. J. 2021, 160, 105676. [Google Scholar] [CrossRef]
  32. Zhang, Y.; Li, Y.J.; Guo, S.Z.; Fu, T.; Zhao, L. A series of heterobimetallic Ni(II)–Ln(III) (Ln = La, Ce, Pr and Nd) coordination polymers derived from 3-EtOsalamo and dicarboxylates: Syntheses, crystal structures and fluorescence properties. Transit. Met. Chem. 2020, 45, 485–492. [Google Scholar] [CrossRef]
  33. Zhang, S.Z.; Chang, J.; Zhang, H.J.; Sun, Y.X.; Wu, Y.; Wang, Y.B. Synthesis, crystal structure and spectral properties of binuclear Ni(II) and cubane-like Cu4(μ3-O)4 cored tetranuclear Cu(II) complexes based on coumarin Schiff base. Chin. J. Inorg. Chem. 2020, 36, 503–514. [Google Scholar]
  34. Kang, Q.P.; Li, X.Y.; Wei, Z.L.; Zhang, Y.; Dong, W.K. Symmetric containing- PMBP N2O2-donors nickel(II) complexes: Syntheses, structures, Hirshfeld analyses and fluorescent properties. Polyhedron 2019, 165, 38–50. [Google Scholar] [CrossRef]
  35. Liu, L.Z.; Yu, M.; Li, X.Y.; Kang, Q.P.; Dong, W.K. Syntheses, structures, Hirshfeld analyses and fluorescent properties of two Ni(II) and Zn(II) complexes constructed from a bis(salamo)-like ligand. Chin. J. Inorg. Chem. 2019, 35, 1283–1294. [Google Scholar]
  36. Wang, L.; Wei, Z.L.; Chen, Z.Z.; Liu, C.; Dong, W.K.; Ding, Y.J. A chemical probe capable for fluorescent and colorimetric detection to Cu2+ and CN− based on coordination and nucleophilic addition mechanism. Microchem. J. 2020, 155, 104801. [Google Scholar] [CrossRef]
  37. Wei, Z.L.; Wang, L.; Wang, J.F.; Guo, W.T.; Zhang, Y.; Dong, W.K. Two highly sensitive and efficient salamo-like copper(II) complex probes for recognition of CN−. Spectrochim. Acta A 2020, 228, 117775. [Google Scholar] [CrossRef]
  38. Wang, L.; Wei, Z.L.; Liu, C.; Dong, W.K.; Ru, J.X. Synthesis and characterization for a highly selective bis(salamo)-based chemical sensor and imaging in living cell. Spectrochim. Acta A 2020, 239, 118496. [Google Scholar] [CrossRef]
  39. Pan, Y.Q.; Zhang, Y.; Yu, M.; Zhang, Y.; Wang, L. Newly synthesized homomultinuclear Co(II) and Cu(II) bissalamo-like complexes: Structural characterizations, Hirshfeld analyses, fluorescence and antibacterial properties. Appl. Organomet. Chem. 2020, 34, e5441. [Google Scholar] [CrossRef]
  40. Liu, C.; Wei, Z.L.; Mu, H.R.; Dong, W.K.; Ding, Y.J. A novel unsymmetric bis (salamo)-based chemosensor for detecting Cu2+ and continuous recognition of amino acids. J. Photochem. Photobio. A 2020, 397, 112569. [Google Scholar] [CrossRef]
  41. Mu, H.R.; Yu, M.; Wang, L.; Zhang, Y.; Ding, Y.J. Catching S2− and Cu2+ by a highly sensitive and efficient salamo-like fluorescence-ultraviolet dual channel chemosensor. Phosphorus Sulfur Silicon Relat. Elem. 2020, 195, 730–739. [Google Scholar]
  42. Xu, X.; Bian, R.N.; Guo, S.Z.; Dong, W.K.; Ding, Y.J. A new asymmetric salamo-based chemical sensor for dual channel detection of Cu2+ and B4O72−. Inorg. Chim. Acta 2020, 513, 119945. [Google Scholar] [CrossRef]
  43. An, X.X.; Zhao, Q.; Mu, H.R.; Dong, W.K. A new half-salamo-based homo-trinuclear nickel(II) complex: Crystal structure, Hirshfeld surface analysis, and fluorescence properties. Crystals 2019, 9, 101. [Google Scholar] [CrossRef] [Green Version]
  44. Zhang, Y.; Pan, Y.Q.; Yu, M.; Xu, X.; Dong, W.K. Single-armed salamo-like dioxime and its multinuclear Cu(II), Zn(II) and Cd(II) complexes: Syntheses, structural characterizations, Hirshfeld analyses and fluorescence properties. Appl. Organomet. Chem. 2019, 33, e5240. [Google Scholar] [CrossRef]
  45. An, X.X.; Liu, C.; Chen, Z.Z.; Xie, K.F.; Dong, W.K. An unexpected trinuclear cobalt(II) complex based on a half-salamo-like ligand: Synthesis, crystal structure, Hirshfeld surface analysis, antimicrobial and fluorescent properties. Crystals 2019, 9, 602. [Google Scholar] [CrossRef] [Green Version]
  46. Li, J.; Zhang, H.J.; Chang, J.; Sun, Y.X.; Huang, Y.Q. Solvent-induced unsymmetric Salamo-like trinuclear NiII complexes: Syntheses, crystal structures, fluorescent and magnetic properties. Crystals 2018, 8, 176. [Google Scholar] [CrossRef] [Green Version]
  47. Yu, M.; Mu, H.R.; Liu, L.Z.; Li, N.; Bai, Y.; Dong, X.Y. Syntheses, structures and Hirshfeld analyses of trinuclear Ni(II) salamo-type complexes. Chin. J. Inorg. Chem. 2019, 35, 1109–1120. [Google Scholar]
  48. Celedón, S.; Dorcet, V.; Roisnel, T.; Singh, A.; Ledoux-Rak, I.; Hamon, J.R.; Carrillo, D.; Manzur, C. Main-chain oligomers from NiII- and CuII-centered unsymmetrical N2O2 Schiff-base complexes: Synthesis and spectral, structural, and second-order nonlinear optical properties. Eur. J. Inorg. Chem. 2014, 29, 4984–4993. [Google Scholar] [CrossRef]
  49. Liu, X.; Manzurc, C.; Novoa, N.; Celedónc, S.; Carrilloc, D.; Hamon, J.R. Multidentate unsymmetrically substituted Schiff bases and their metal complexes: Synthesis, functional materials properties, and applications to catalysis. Coord. Chem. Rev. 2018, 357, 144–172. [Google Scholar] [CrossRef]
  50. Wang, L.; Pan, Y.Q.; Wang, J.F.; Zhang, Y.; Ding, Y.J. A highly selective and sensitive half-salamo-based fluorescent chemosensor for sequential detection of Pb(II) ion and Cys. J. Photochem. Photobio. A 2020, 400, 112719. [Google Scholar] [CrossRef]
  51. Zhao, Q.; An, X.X.; Liu, L.Z.; Dong, W.K. Syntheses, luminescences and Hirshfeld surfaces analyses of structurally characterized homo-trinuclear ZnII and hetero-pentanuclear ZnII-LnIII (Ln = Eu, Nd) bis(salamo)-like complexes. Inorg. Chim. Acta 2019, 490, 6–15. [Google Scholar] [CrossRef]
  52. Dong, Y.J.; Dong, X.Y.; Dong, W.K.; Zhang, Y.; Zhang, L.S. Three asymmetric salamo-type copper(II) and cobalt(II) complexes: Syntheses, structures and fluorescent properties. Polyhedron 2017, 123, 305–315. [Google Scholar] [CrossRef]
  53. Song, X.Q.; Wang, L.; Zheng, Q.F.; Liu, W.S. Synthesis, crystal structure and luminescence properties of lanthanide complexes with a new semirigid bridging furfurylsalicylamide ligand. Inorg. Chim. Acta 2013, 391, 171–178. [Google Scholar] [CrossRef]
  54. Dong, X.Y.; Kang, Q.P.; Li, X.Y.; Ma, J.C.; Dong, W.K. Structurally characterized solvent-induced homotrinuclear cobalt(II) N2O2− donor bisoxime-type complexes. Crystals 2018, 8, 139. [Google Scholar] [CrossRef] [Green Version]
  55. Wang, L.; Wei, Z.L.; Yu, M.; Pan, Y.Q.; Zhang, Y.; Dong, W.K. Multihalogen-substituted salamo-type Mn(II) complexes: Syntheses, crystal structures, Hirshfeld analyses and fluorescence properties. Chin. J. Inorg. Chem. 2019, 35, 1791. [Google Scholar]
  56. Li, Y.J.; Bian, R.N.; Li, P.; Xie, K.F.; Dong, W.K. Investigation of supram-olecular assemblies, Hirshfeld surfaces and DFT analyses, and fluorescence properties of three newly synthesized multinuclear Co(II), Ni(II) and Zn(II) complexes. Polyhedron 2020, 192, 114867. [Google Scholar] [CrossRef]
  57. Xu, L.; Yu, M.; Li, L.H.; Ma, J.C.; Dong, W.K. A heterotetranuclear zinc(II)—cerium(IV) salamo complex possessing deca- and dodeca-coordinated cerium(IV) atoms: Synthesis, structure, and photophysical properties. J. Struct. Chem. 2019, 60, 1358. [Google Scholar] [CrossRef]
  58. Akine, S.; Taniguchi, T.; Nabeshima, T. Synthesis and characterization of novel ligands 1,2-bis(salicylideneaminooxy)ethanes. Chem. Lett. 2001, 30, 682–683. [Google Scholar] [CrossRef]
  59. Zhang, Y.; Liu, L.Z.; Peng, Y.D.; Li, N.; Dong, W.K. Structurally characterized trinuclear nickel(II) and copper(II) salamo-type complexes: Syntheses, Hirshfeld analyses and fluorescent properties. Transit. Met. Chem. 2019, 44, 627–639. [Google Scholar] [CrossRef]
  60. Shaan, A.; Monika, T.; Kumar, J.P.; Vinay, G. Insight into the gas phase dissociation of CF3CH2I and its reactions with H and OH by first principles. J. Mol. Model. 2018, 24, 315. [Google Scholar]
  61. Jone Celestina, J.; Tharmaraj, P.; Jeevika, A.; Sheela, C.D. Fabrication of triazine based colorimetric and electrochemical sensor for the quantification of Co2+ ion. Microchem. J. 2020, 155, 104692. [Google Scholar] [CrossRef]
  62. Bian, R.N.; Xu, X.; Feng, T.; Dong, W.K. A novle O-phenanthroline-based bis(half-salamo)-like chemical sensor: For rapid and efficient continuous recognition of Cu2+, HPO42− and H2PO4−. Inorg. Chim. Acta 2020, 516, 120098. [Google Scholar] [CrossRef]
  63. Spackman, M.A.; McKinnon, J.J.; Jayatilaka, D. Electrostatic potentials mapped on Hirshfeld surfaces providedirect insight into intermolecular interactions in crystals. CrystEngCommun 2008, 10, 377–388. [Google Scholar]
  64. Chen, Z.Z.; Zhang, W.Z.; Zhang, T.; Zhang, Y.; Dong, W.K. An insight into the molecular structures, theoretical calculation and catalytic activities of novel heterotrinuclear [CuII2CeIII] and heterohexanuclear [CuII4YIII2] bis(salamo)-based complexes. New J. Chem. 2020, 44, 19836–19849. [Google Scholar] [CrossRef]
  65. Xu, X.; Wang, J.F.; Bian, R.N.; Zhao, L. Synthesis, structure, Hirshfeld analysis and fluorescence properties of a new asymmetric salamo-based ligand and its Cu(II) complex involving oxime oxygen cooedination. J. Coord. Chem. 2020, 15, 2209–2223. [Google Scholar] [CrossRef]
  66. Spackman, M.A.; Jayatilaka, D. Hirshfeld surface analysis. CrystEngCommun 2009, 11, 19–32. [Google Scholar] [CrossRef]
  67. Wang, J.F.; Li, R.Y.; Li, P.; Dong, W.K. Exploring coordination behaviors, structural characterizations and theoretical calculations of structurally different Cu(II), Co(II) and Ni(II) emissive complexes constructed from a salamo-based ligand and 4,4′-bipy. Inorg. Chim. Acta 2021, 518, 120247. [Google Scholar] [CrossRef]
  68. Xu, X.; Feng, T.; Feng, S.S.; Dong, W.K. Influence of structural variation of salamo-based ligand on supramolecular architectures, Hirshfeld analyses, and fluorescence properties of new tetranuclear NiII complexes. Appl. Organomet. Chem. 2021, 35, e6057. [Google Scholar] [CrossRef]
  69. Wang, J.F.; Xu, X.; Bian, R.N.; Dong, W.K.; Ding, Y.J. Investigation on structurally different Cu(II) and Ni(II) complexes constructed from a novel pyridine-terminal salamo-like ligand. Inorg. Chim. Acta 2021, 516, 120095. [Google Scholar] [CrossRef]
Crystals 11 00113 sch001 550
Scheme 1. Synthesis procedure of H2L.
Scheme 1. Synthesis procedure of H2L.
Crystals 11 00113 sch001
Crystals 11 00113 g001 550
Figure 1. UV-Vis spectra of H2L and its CuII complex.
Figure 1. UV-Vis spectra of H2L and its CuII complex.
Crystals 11 00113 g001
Crystals 11 00113 g002 550
Figure 2. UV-Visible spectrum changes of H2L (10 µM) upon addition of different amounts of CuII ions (0~2 equiv.). Inset: The absorbance at 460 nm varied as an interaction of [Cu2+]/[H2L].
Figure 2. UV-Visible spectrum changes of H2L (10 µM) upon addition of different amounts of CuII ions (0~2 equiv.). Inset: The absorbance at 460 nm varied as an interaction of [Cu2+]/[H2L].
Crystals 11 00113 g002
Crystals 11 00113 g003 550
Figure 3. (a) Crystal structure of the CuII complex; (b) Coordination polyhedra of the CuII atoms.
Figure 3. (a) Crystal structure of the CuII complex; (b) Coordination polyhedra of the CuII atoms.
Crystals 11 00113 g003
Crystals 11 00113 g004 550
Figure 4. The intramolecular hydrogen bonds of the CuII complex.
Figure 4. The intramolecular hydrogen bonds of the CuII complex.
Crystals 11 00113 g004
Crystals 11 00113 g005 550
Figure 5. Surface plots of HOMO-LUMO of H2L (left) and its CuII complex (right).
Figure 5. Surface plots of HOMO-LUMO of H2L (left) and its CuII complex (right).
Crystals 11 00113 g005
Crystals 11 00113 g006 550
Figure 6. Fluorescent spectra of H2L and its CuII complex (λex = 349 nm).
Figure 6. Fluorescent spectra of H2L and its CuII complex (λex = 349 nm).
Crystals 11 00113 g006
Crystals 11 00113 g007 550
Figure 7. Hirshfeld surfaces analyses mapped with (a) dnorm, (b) shape index, and (c) curvedness of the CuII complex.
Figure 7. Hirshfeld surfaces analyses mapped with (a) dnorm, (b) shape index, and (c) curvedness of the CuII complex.
Crystals 11 00113 g007
Crystals 11 00113 g008 550
Figure 8. Fingerprint plot of the CuII complex: full and resolved into O···H, C···H and H···H connects reflecting the associated percentages of connects devoted to the whole Hirshfeld surface region of the CuII complex.
Figure 8. Fingerprint plot of the CuII complex: full and resolved into O···H, C···H and H···H connects reflecting the associated percentages of connects devoted to the whole Hirshfeld surface region of the CuII complex.
Crystals 11 00113 g008
Table
Table 1. Crystal and refinement parameters data of the CuII complex.
Table 1. Crystal and refinement parameters data of the CuII complex.
CompoundThe CuII Complex
Empirical formula
Formula weight		C46H54Cl6Cu3N4O19
1370.25
T, (K)173(2)
Crystal systemTetragonal
Space groupI41/a
a/(Å)28.3010(7)
b/(Å)28.3010(7)
c/(Å)15.1845(7)
α/(°)90
β/(°)90
γ/(°)90
Volume (Å3)12162.0(8)
Z8
Dcalc (g/cm3)1.497
μ/(mm−1)1.373
F(000), e5592.0
Crystal size/mm30.22 × 0.2 × 0.18
Ɵ Range (°)4.19 to 53.996
Index ranges−17 ≤ h ≤ 36, −26 ≤ k ≤ 29, −19 ≤ l ≤ 10
Reflections collected13026
Independent reflections6539 [Rint = 0.0055, Rsigma = 0.0537]
Data/restraints/parameters6539/1/395
GOF1.001
Final R1, wR2 indexesR1 = 0.0441, wR2 = 0.1281
Final R1, wR2 indexes [all data]R1 = 0.0575, wR2 = 0.1323
Largest differences peak and hole/ e Å−30.41/−1.07
R1 = Σ||Fo|−|Fc||/Σ|Fo|; wR2 = [Σw (Fo2−Fc2)2/Σw(Fo2)2]1/2, w = [σ2(Fo2)+(AP)2+BP]–1. Where P = (Max(Fo2, 0)+2Fc2)/3; GOF = S = [Σw(Fo2−Fc2)2/(nobs–nparam)]1/2.
Table
Table 2. The main IR bands for H2L and its CuII complex cm−1.
Table 2. The main IR bands for H2L and its CuII complex cm−1.
Compoundν(O-H)ν(C=N)v(Ar-O)ν(Cu-O)ν(Cu-N)
H2L321616091261--
The CuII complex342016031250455512
Table
Table 3. Significant bond lengths (Å) and angles (◦) of the CuII complex.
Table 3. Significant bond lengths (Å) and angles (◦) of the CuII complex.
BondLengthsBondLengths
Cu1-O42.024(3)Cu2-O42.081(3)
Cu1-O12.017(3)Cu2-O12.073(3)
Cu1-O52.040(3)Cu2-O1#2.073(3)
Cu1-N12.072(4)Cu2-O62.063(3)
Cu1-N22.063(4)Cu2-O6#2.063(3)
Cu1-O72.118(3)Cu2-O4#2.081(3)
BondAnglesBondAngles
O1-Cu1-N187.90(13)O1-Cu2-O4#101.66(11)
O1-Cu1-O480.95(11)O1#-Cu2-O1180.00(13)
O1-Cu1-O590.75(12)O1#-Cu2-O4101.66(11)
O1-Cu1-O790.15(13)O1#-Cu2-O4#78.34(11)
O4-Cu1-O592.39(13)O4-Cu2-O4#180.00
O4-Cu1-O790.94(13)O6-Cu2-O189.50(12)
O4-Cu1-N1168.25(13)O6-Cu2-O1#90.50(12)
O4-Cu1-N286.18(13)O6-Cu2-O488.55(12)
O5-Cu1-O7176.64(13)O6-Cu2-O4#91.45(12)
O5-Cu1-N191.42(15)O6-Cu2-O6#180.00(9)
O5-Cu1-N290.92(14)O6#-Cu2-O4#88.55(12)
N1-Cu1-O7
N2-Cu1-O7		85.39(15)
88.92(14)		O6#-Cu2-O1
O6#-Cu2-O1#		90.50(12)
89.50(12)
N2-Cu1-N1104.87(15)O6#-Cu2-O491.45(12)
O1-Cu2-O478.34(11)
Symmetry transformations used to generate equivalent atoms: #1 1+x, y, z.
Table
Table 4. Intramolecular hydrogen bonding data [Å,°] of the CuII complex.
Table 4. Intramolecular hydrogen bonding data [Å,°] of the CuII complex.
D−H···AD(D−H)d(H···A)d(D···A)∠D−H···ASymmetry Codes
O7−H7A···N20.842.622.930(5)1031-x,1-y,-z
O7−H7B···O40.822.582.955(4)1091-x,1-y,-z
C9′−H9′A···O50.972.363.181(12)1421-x,1-y,-z
Table
Table 5. Frontier molecular orbital energies and molecule energies of H2L and its CuII complex.
Table 5. Frontier molecular orbital energies and molecule energies of H2L and its CuII complex.
NameEnergy/HaEHOMO/eVELUMO/eV∆E/eV
C20H18N2O4 (H2L)−1183.9−5.277−2.9172.36
C44H42Cu3N4O14−7894.1−5.014−3.0281.986
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Peng, Y.-D.; Li, R.-Y.; Li, P.; Sun, Y.-X. Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex. Crystals 2021, 11, 113. https://doi.org/10.3390/cryst11020113

AMA Style

Peng Y-D, Li R-Y, Li P, Sun Y-X. Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex. Crystals. 2021; 11(2):113. https://doi.org/10.3390/cryst11020113

Chicago/Turabian Style

Peng, Yun-Dong, Ruo-Yu Li, Peng Li, and Yin-Xia Sun. 2021. "Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex" Crystals 11, no. 2: 113. https://doi.org/10.3390/cryst11020113

APA Style

Peng, Y. -D., Li, R. -Y., Li, P., & Sun, Y. -X. (2021). Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex. Crystals, 11(2), 113. https://doi.org/10.3390/cryst11020113

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop