Synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) complex of 1,2-bis(pyridin-2-ylmethylene)hydrazine European Journal of Chemistry 13 (1) (2022) 1-7 European Journal of Chemistry ISSN 2153-2249 (Print) / ISSN 2153-2257 (Online) – Copyright © 2022 The Authors – Atlanta Publishing House LLC – Printed in the USA. This work is published and licensed by Atlanta Publishing House LLC – CC BY NC – Some Rights Reserved. https://dx.doi.org/10.5155/eurjchem.13.1.1-7.2166 European Journal of Chemistry View Journal Online View Article Online Synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) complex of 1,2-bis(pyridin-2-ylmethylene)hydrazine Meman Sahu 1, Amit Kumar Manna 1, Dinesh De 2 and Goutam Kumar Patra 1,* 1 Department of Chemistry, Faculty of Physical Sciences, Guru Ghasidas Vishwavidyalaya, Bilaspur (Chhattisgarh), 495009, India 2 Department of Basic Science, Vishwavidyalaya Engineering College, Ambikapur, CSVTU-Bhilai, Chhattisgarh, 497001, India * Corresponding author at: Department of Chemistry, Faculty of Physical Sciences, Guru Ghasidas Vishwavidyalaya, Bilaspur (Chhattisgarh), 495009, India. e-mail: goutam.patra@ggu.ac.in (G.K. Patra). 10.5155/eurjchem.13.1.1-7.2166 Received: 30 July 2021 Received in revised form: 05 September 2021 Accepted: 17 October 2021 Published online: 31 March 2022 Printed: 31 March 2022 We report the synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) perchlorate complex (1, Ni2L3·4ClO4·2CH3CN) of 1,2-bis(pyridin-2- ylmethylene)hydrazine (L) ligand. The X-ray crystallographic study of complex 1 reveals that in the presence of Ni(II) ions,the ligand L forms a dimeric triple helix with a Ni(II)-Ni(II) distance of 3.794 Å. Crystal data for C40H36Cl4N14Ni2O16: Monoclinic, space group P21/c (no. 14), a = 20.7558(19) Å, b = 13.1937(12) Å, c = 20.0181(18) Å, β = 96.9510(10)°, V = 5441.6(9) Å3, Z = 4, T = 293.15 K, μ(MoKα) = 0.965 mm-1, Dcalc = 1.498 g/cm3, 38075 reflections measured (1.976° ≤ 2Θ ≤ 43.728°), 6557 unique (Rint = 0.0695, Rsigma = 0.0466) which were used in all calculations. The final R1 was 0.0518 (I > 2σ(I)) and wR2 was 0.1270 (all data). The Hirshfeld surface analysis of complex 1 shows that C···H, H···H, N···H and O···H interactions of 10.9, 26.4, 6.7, and 33.4%; respectively, which exposed that the main intermolecular interactions were H···H intermolecular interactions. Hydrazone Ni(II)triple helix Crystal structure 2-Pyridinaldazine Hirshfield surface analysis 1,2-Bis(Pyridin-2-ylmethylene)hydrazine Cite this: Eur. J. Chem. 2022, 13(1), 1-7 Journal website: www.eurjchem.com 1. Introduction The simplest bis-pyridylimine ligand system is 1,2- bis(pyridin-2-ylmethylene)hydrazine (L) in which, two pyridin- 2-ylmethanimine binding units are linked directly (no spacer) through the imine nitrogen atoms. L has the freedom to rotate about the central N-N bond. The coordination chemistry of L was first reported by Stratton and Busch in papers in 1958 and 1960 [1-3] and their studies are of specific historic importance to the field of metallo-supramolecular chemistry and in parti- cular to helicate formation [4,5]. These scientists described the coordination of L with transition metal ions to form octahedral complexes with the formula [M2(L)3]4+ (M = Co2+, Fe2+ etc.) and documented that the species must comprise of three strands enfolded around two metals in a spiral fashion [6,7]. Their studies show the first recognized triple helicates. Helical complexes were exposed to exchange reactions on heating or standing to form mononuclear complexes [M(L)2]2+ in which the ligand twists to coordinate as a tridentate with a non- coordinated imine residue. Stratton and Busch proposed the term 'flexidentate' to describe the coordination behavior of ligand L [1-3]. Sheldrick et al. reported the X-ray crystal structure of the dinuclear triple-helical cobalt (II) complex formed from the pyridylmethyl ketazine ligand [8]. Hanon et al. first structurally characterized the dimeric Ag(I) triple helicate of L [9]. The relative positioning of the N atoms on the terminal pyridine ring and in the central part of the ligand L can easily be modified as needed in the design [10]. The ligand L can chelate any metal ion due to the close proximity of the pyridine ring N atom and the imine N atom of the body of the ligand [11]. Aggravated by the above facts and in continuation of our ongoing research work in search for metal complexes of imino- pyridyl ligands of potential importance [12-18], we have reported here the synthesis, crystal structure and Hirshfeld surface analysis of the nickel(II) complex of 1,2-bis(pyridin-2- ylmethylene)hydrazine. 2. Experimental 2.1. Materials and physical measurements All chemicals used in this study were purchased from Aldrich Chemical Company, USA, and Acros Chemical Company, USA, and used without further purification unless otherwise mentioned. The melting point was determined by an electro- thermal IA9000 series digital melting point apparatus and is uncorrected. Microanalyses were performed using a Perkin Elmer 2400II elemental analyzer. ABSTRACT RESEARCH ARTICLE KEYWORDS https://dx.doi.org/10.5155/eurjchem.13.1.1-7.2166 https://www.eurjchem.com/ https://dx.doi.org/10.5155/eurjchem.13.1.1-7.2166 mailto:goutam.patra@ggu.ac.in http://www.eurjchem.com/ https://crossmark.crossref.org/dialog/?doi=10.5155/eurjchem.13.1.1-7.2166&domain=pdf&date_stamp=2022-03-31 2 Sahu et al. / European Journal of Chemistry 13 (1) (2022) 1-7 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.1.1-7.2166 Table 1. Crystal data and structure refinement for complex 1. Empirical formula C40H35Cl4N14Ni2O16 Formula weight 1227.04 Temperature (K) 293.15 Crystal System Monoclinic Space group P21/c a, (Å) 20.7558(19) b, (Å) 13.1937(12) c, (Å) 20.0181(18) α (°) 90 β (°) 96.9510(10) γ (°) 90 Volume (Å3) 5441.6(9) Z 4 ρcalc(g/cm3) 1.498 μ (mm-1) 0.965 F(000) 2500.0 Crystal size (mm3) 0.18 × 0.16 × 0.12 Radiation MoKα (λ = 0.71073) 2Θ range for data collection (°) 1.976 to 43.728 Index ranges -21 ≤ h ≤ 21, -13 ≤ k ≤ 13, -20 ≤ l ≤ 20 Reflections collected 38075 Independent reflections 6557 [Rint = 0.0695, Rsigma = 0.0466] Data/restraints/parameters 6557/0/724 Goodness-of-fit on F2 1.050 Final R indexes [I≥2σ (I)] R1 = 0.0518, wR2 = 0.1192 Final R indexes [all data] R1 = 0.0675, wR2 = 0.1270 Largest diff. peak/hole (e.Å-3) 0.90/-0.75 Infrared (IR) and solution electronic spectra were recorded on Nicolet Magna IR (Series II) and Shimadzu UV-160A spectro- photometers, respectively. ESI-mass spectra were recorded on a Waters mass spectrometer using mixed solvent methanol and triple distilled water. 2.2. Synthesis of the ligand,1,2-bis(pyridin-2-ylmethylene) hydrazine (L) The ligand L was prepared by refluxing 2-pyridine- carboxaldehyde and hydrazine hydrate in 2:1 molar ratio in methanol, following the reported procedure [1,3]. 1,2-Bis(Pyridin-2-ylmethylene)hydrazine (L): Color: Yellow. Yield: 85%. M.p.: 113-115 °C. ESI-MS (m/z, %): 211.23 (L+, 100%). Anal. calcd. for C12H10N4: C, 68.56; H, 4.79; N, 26.65. Found: C, 68.78.; H, 4.67; N, 26.44%. FT-IR (KBr, ν, cm-1): 2925 (wb, Aromatic C-H), 1628 (vs, C=N), 1485 (s, N-N), 1043 (m, Aliphatic C-H). UV-Vis (CH3OH, λ, nm (ε, M-1cm-1)): 210 (8200), 237 (13800), 275 (9400). 2.3. Synthesis of nickel(II) perchlorate complex (1) To 20 mL yellowish methanol solution of L (0.158 g, 0.75 mmol) was added solid Ni(ClO4)2.6H2O (0.185 g, 0.50 mmol). The reaction mixture was stirred for 3 h. The brown precipitate obtained was filtered off and dried in air. It was then dissolved in acetonitrile and kept in the refrigerator overnight. Reddish brown crystalline complexes suitable for X-ray single crystal diffraction analysis were obtained, filtered off, washed with 5 mL of methanol, and dried in vacuum over fused CaCl2. The single crystals of complex 1 were obtained by the direct diffusion of diethyl ether in the acetonitrile solution of L. Complex 1: Color: Reddish brown. Yield: 75%. M.p.: 200- 201 °C. FT-IR (KBr, ν, cm-1): 3437 (wb), 3043 (w), 2947 (m), 2856 (m), 2015 (w) 1645 (s), 1615 (s), 1458 (w), 1412 (m), 1318 (w), 1245 (m), 1107 (s), 825 (s), 629 (s). CAUTION! Although while working with the perchlorate complex described here, we have not met with any incident, care should be taken in handling them, as perchlorates are potentially explosive. They should not be prepared and stored in large amounts. 2.4. X-ray crystallography Single crystal X-ray data of complex 1 was collected using MoKα (λ = 0.71073 Å) radiation on a Bruker APEX II diffract- tometer equipped with CCD area detector. The crystal was kept at 293.15 K during data collection. Using Olex2 [19], the structure was solved with the SHELXS [20] structure solution program using Direct Methods and refined with the SHELXL [21] refinement package using Least Squares minimisation. Atoms other than hydrogen atoms were treated anisotropically. The hydrogen atoms were geometrically fixed. The crystallo- graphic details of complex 1 are summarized in Table 1, the selected bond lengths and angles of complex 1 are also listed in Tables 2 and 3. 2.5. Hirshfeld surface calculations For obtaining additional insight into the intermolecular interaction of molecular crystals, Hirshfeld surface analysis helps as a powerful set-up. The size and shape of Hirshfeld surface allow the qualitative and quantitative study and imagining of intermolecular close contacts in molecular crystals [22]. Molecular Hirshfeld surfaces are built based on electron distribution calculated as the sum of spherical atom electron densities [23,24]. Thus, an isosurface is obtained, and for each point of the isosurface, two distances can be defined: de, the distance from the point to the nearest atom outside to the surface, and di, the distance to the nearest atom inside to the surface. Furthermore, the identification of the regions of particular importance for intermolecular interactions is achieved by mapping the normalized contact distance (dnorm), expressed as: dnorm = (di-rivdw)/rivdw+(de-revdw)/revdw; where rivdw and revdw are the van der Waals radii of the atoms [25]. The value of dnorm is negative or positive when intermolecular contacts are shorter than or longer than rvdw, respectively. Sahu et al. / European Journal of Chemistry 13 (1) (2022) 1-7 3 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.1.1-7.2166 Table 2. Selected bond lengths for complex 1. Atom Atom Length (Å) Atom Atom Length (Å) Atom Atom Length (Å) Ni1 N3 2.084(4) C11 C12 1.465(8) C23 C22 1.386(8) Ni1 N4 2.090(4) C8 C7 1.380(8) C23 N7 1.340(7) Ni1 N5 2.085(4) C8 C9 1.364(8) C21 C22 1.381(8) Ni1 N11 2.084(4) C7 N3 1.336(7) N8 C24 1.094(11) Ni1 N12 2.086(4) C9 C10 1.395(8) C24 C25 1.465(13) Ni1 N13 2.090(4) N4 C12 1.272(6) N9 C26 1.364(7) Ni2 N1 2.085(4) N4 N10 1.400(6) N9 C30 1.338(7) Ni2 N2 2.080(4) C16 C17 1.384(7) C26 C27 1.378(7) Ni2 N6 2.078(4) C16 C15 1.385(8) C26 C31 1.467(7) Ni2 N7 2.074(4) C37 C36 1.372(8) C27 C28 1.386(8) Ni2 N9 2.076(4) C17 N5 1.347(7) C30 C29 1.391(8) Ni2 N10 2.083(4) C17 C32 1.456(7) C28 C29 1.373(8) C1 C2 1.375(7) C14 C13 1.387(8) N10 C31 1.277(7) C1 N1 1.354(7) C14 C15 1.357(8) C32 N11 1.273(6) C1 C6 1.466(7) C13 N5 1.345(7) N12 C34 1.360(7) C2 C3 1.394(8) N6 C50 1.272(6) N12 C35 1.332(7) C3 C4 1.354(8) N6 N11 1.403(6) N13 C33 1.277(6) C4 C5 1.392(8) C19 C20 1.380(8) C34 C33 1.481(7) C5 N1 1.338(7) C19 C50 1.462(7) C34 C38 1.379(7) N2 C6 1.273(6) C19 N7 1.350(7) C35 C36 1.390(8) N2 N13 1.401(6) C20 C21 1.375(8) C38 C37 1.386(8) C11 C10 1.378(8) C11 N3 1.357(7) N15 C42 1.092(8) Table 3. Bond angles for complex 1. Atom Atom Atom Angle (°) Atom Atom Atom Angle (°) Atom Atom Atom Angle (°) N3 Ni1 N4 76.97(17) C5 N1 Ni2 127.3(4) C21 C20 C19 119.0(5) N3 Ni1 N5 95.46(17) C5 N1 C1 118.3(5) N7 C23 C22 122.2(6) N3 Ni1 N11 100.69(16) C6 N2 Ni2 117.0(4) C20 C21 C22 119.1(6) N3 Ni1 N12 96.62(16) C6 N2 N13 121.0(4) N6 C50 C19 115.5(5) N3 Ni1 N13 163.05(17) N13 N2 Ni2 121.0(3) C21 C22 C23 119.1(6) N4 Ni1 N13 88.51(16) N2 C6 C1 116.2(5) C19 N7 Ni2 114.4(3) N5 Ni1 N4 161.85(17) C10 C11 C12 122.7(5) C23 N7 Ni2 127.1(4) N5 Ni1 N12 96.88(17) N3 C11 C10 123.0(5) C23 N7 C19 118.2(5) N5 Ni1 N13 100.91(16) N3 C11 C12 114.3(5) N8 C24 C25 169.7(14) N11 Ni1 N4 88.00(17) C9 C8 C7 119.3(6) C26 N9 Ni2 114.3(3) N11 Ni1 N5 77.10(17) N3 C7 C8 123.4(6) C30 N9 Ni2 128.4(4) N11 Ni1 N12 162.11(17) C8 C9 C10 118.8(5) C30 N9 C26 117.2(5) N11 Ni1 N13 87.30(16) C11 C10 C9 118.5(6) N9 C26 C27 122.9(5) N12 Ni1 N4 100.35(16) C11 N3 Ni1 114.8(3) N9 C26 C31 115.1(5) N12 Ni1 N13 77.22(16) C7 N3 Ni1 128.3(4) C27 C26 C31 121.9(5) N2 Ni2 N1 77.34(17) C7 N3 C11 116.9(5) C26 C27 C28 119.0(6) N2 Ni2 N10 88.17(17) C12 N4 Ni1 116.2(4) N9 C30 C29 122.5(6) N6 Ni2 N1 99.72(16) N15 C42 C43 178.2(9) C29 C28 C27 118.5(5) N6 Ni2 N2 87.78(16) N12 C35 C36 123.3(5) C28 C29 C30 119.8(6) N6 Ni2 N10 89.18(17) C12 N4 N10 120.2(4) N4 N10 Ni2 120.6(3) N7 Ni2 N1 94.86(17) N10 N4 Ni1 120.6(3) C31 N10 Ni2 117.0(4) N7 Ni2 N2 161.72(17) N4 C12 C11 116.3(5) C31 N10 N4 119.3(5) N7 Ni2 N6 77.17(17) C17 C16 C15 119.0(5) N10 C31 C26 115.5(5) N7 Ni2 N9 99.00(17) C16 C17 C32 122.0(5) N11 C32 C17 116.4(5) N7 Ni2 N10 101.74(17) N5 C17 C16 122.9(5) N6 N11 Ni1 121.6(3) N9 Ni2 N1 95.01(17) N5 C17 C32 115.1(5) C32 N11 Ni1 116.7(4) N9 Ni2 N2 98.13(16) C15 C14 C13 119.5(5) C32 N11 N6 120.4(4) N9 Ni2 N6 165.02(17) N5 C13 C14 122.9(5) C34 N12 Ni1 114.3(3) N9 Ni2 N10 77.33(18) C14 C15 C16 118.8(5) C35 N12 Ni1 128.6(4) N10 Ni2 N1 162.58(17) C17 N5 Ni1 114.5(3) C35 N12 C34 117.0(4) C2 C1 C6 122.1(5) C13 N5 Ni1 128.6(4) N2 N13 Ni1 121.4(3) N1 C1 C2 122.9(5) C13 N5 C17 116.9(5) C33 N13 Ni1 117.9(3) N1 C1 C6 114.9(5) C50 N6 Ni2 117.3(4) C33 N13 N2 119.7(4) C1 C2 C3 118.1(6) C50 N6 N11 120.9(4) N12 C34 C33 115.4(5) C4 C3 C2 119.1(6) N11 N6 Ni2 121.0(3) N12 C34 C38 123.4(5) C3 C4 C5 120.3(6) C20 C19 C50 122.3(5) C38 C34 C33 121.1(5) N1 C5 C4 121.2(6) N7 C19 C20 122.5(5) N13 C33 C34 114.9(5) C1 N1 Ni2 114.3(3) N7 C19 C50 115.2(5) C34 C38 C37 118.0(5) The graphical plots of the molecular Hirshfeld surfaces mapped with dnorm employ the red-white-blue color scheme, where the red color indicates the shorter intermolecular contacts, white color shows the contacts around the rvdw separation, and blue color is used to point out the longer contact distances. Due to the symmetry between de and di in the expression for dnorm, where two Hirshfeld surfaces touch, both will display a red spot identical in color intensity as well as size and shape [26]. The mixture of de and di in the form of a 2D fingerprint plot provides a summary of intermolecular contacts in the crystal and are in complement to the Hirshfeld surfaces [22]. The information about the intermolecular interactions in the immediate environment of each molecule in the asymmetric unit is achieved by such plots. In addition, the close contacts between particular atom types can be highlighted in so-called resolved fingerprint plots [27], which allow the facile assignment of an intermolecular contact to a certain type of interaction and quantitatively summarize the nature and type of intermolecular contacts. Two additional colored properties (shape index and curvedness) based on the local curvature of the surface can also be specified [28]. The Hirshfeld surfaces are mapped with dnorm, shape-index, curvedness and 2D fingerprint plots (full and resolved) reported in this manuscript were generated using Crystal-Explorer 3.1 [29]. 4 Sahu et al. / European Journal of Chemistry 13 (1) (2022) 1-7 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.1.1-7.2166 Scheme 1. Synthesis of complex 1. Figure 1. The molecular structure of complex 1. Figure 2. The packing diagram of complex 1. 3. Results and discussion 3.1. Synthetic aspects The ligand L is 2 + 1 condensates of 2-pyridinecarbaldehyde and hydrazine (Scheme 1). The reddish brown Ni(II) per- chlorate complex (1) has been synthesized in good yield by reacting Ni(ClO4)2 with the ligand L at room temperature in a 2:3 molar proportion. Complex 1 has been characterized by elemental analysis and IR spectra as well as by single crystal X- ray diffraction studies. 3.2. Structural description of complex 1 The Ni(II) complex of L crystallizes with two molecules of acetonitrile. The X-ray crystallographic study of complex 1 reveals that in the presence of Ni(II) ions the ligand gives rise to a dimeric triple helix (Figure 1). The packing diagram of complex 1 has been presented in Figure 2. Each Ni(II) center binds to three ligand strands thereby attaining a pseudo- octahedral coordination geometry. The two Ni(II) centers are separated by a distance of 3.794 Å. Sahu et al. / European Journal of Chemistry 13 (1) (2022) 1-7 5 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.1.1-7.2166 (a) (b) (c) Figure 3. Hirshfeld surfaces of complex 1, (a) 3D dnorm surface, (b) shape index and (c) curvedness. (a) (b) (c) (d) Figure 4. 2D fingerprint plots of complex 1, (a) standard full, (b) resolved into C···H, (c) resolved into O···H and (d) H···H contacts, showing the percentages of contacts that contribute to the total Hirshfeld surface area of the molecule. The bond lengths to the imine groups (mean 2.086 Å) are slightly longer than those to the pyridine units (mean 2.083 Å). This may be a consequence of the helical structure, but could also imply more effective σ-donation or π-back donation. The imine units are fundamentally planar and the helical twist is achieved primarily by twisting about the central N–N bond. There are no significant π-π interactions between the pyridine rings either within or without the helicates. However, other supramolecular interactions are present in the structure. Consistent with this, two molecules of the acetonitrile solvent per helical cation are incorporated into the crystal lattice, and these solvent molecules appear to play an important role in the supra-molecular stabilization of the acidic imine-CH protons. Amongst the four perchlorate anions, two are disordered. 3.3. Theoretical investigations The Hirshfeld surface is a suitable tool for describing the surface characteristics of molecules. The molecular Hirshfeld surface of complex 1 was generated using a standard (high) surface resolution with the 3D dnorm surfaces mapped over a fixed color scale of -0.22 (red) to 1.4 Å (blue). The shape index mapped in the color range of -0.99 to 1.0, and Curvedness was in the range of -4.0 to 0.4. The surfaces were shown to be transparent to allow visualization of the molecular moiety in a similar orientation for all of the structures around which they were calculated. The molecular Hirshfeld surface (dnorm, Shape index and Curvedness) of complex 1 has been shown in Figure 3. 6 Sahu et al. / European Journal of Chemistry 13 (1) (2022) 1-7 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.1.1-7.2166 The dispositions adopted by the molecules in the crystal packing lead to close contact that could be quantified by the mapping of the two-dimensional fingerprint. The fingerprint plot indicates the contributions of interatomic contacts to the Hirshfeld surfaces of the crystal packing. The Hirshfeld surface analysis of complex 1 shows that C···H, O···H, and H···H interactions of 10.9, 33.4, and 26.4%, respectively, from which it is clear that the main intermolecular interactions are O···H intermolecular interactions. Both the C···H and N···H interactions were represented almost same area by a small area in the right side of the top in the 2D fingerprint map, whereas the O···H interactions were represented by the largest in the fingerprint plot (Figure 4) and thus had the most significant contribution to the total Hirshfeld surfaces (33.4 %). 4. Conclusion Herein, the shortest bis Schiff base imino-pyridyl ligand L and its Ni(II) perchlorate complex 1 have been reported. The detailed X-ray single crystal structure and theoretical studies of complex 1 have also been performed. Complex 1 represents a dinuclear triple helix of L. A pseudo-octahedral geometry has been observed in the X-ray single crystal structure of complex 1. The Hirshfeld surface analysis of the complex 1 shows that C···H, O···H, and H···H interactions of 10.9, 33.4, and 26.4%, respectively. Acknowledgements Goutam Kumar Patra would like to thank the Department of Science and Technology (SR/FST/CSI-264/2014 and EMR/2017/0001789) and the Department of Biotechnology, Government of India, New Delhi for financial support. Meman Sahu thanks the Council for Scientific and Industrial Research, Government of India, for financial support in the form of research fellowships. Supporting information CCDC-807524 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via https://www.ccdc.cam. ac.uk/structures/, or by e-mailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223-336033. Disclosure statement Conflict of interest: The authors declare that they have no conflict of interest. Ethical approval: All ethical guidelines have been adhered. Sample availability: Samples of the compounds are available from the author. CRediT authorship contribution statement Conceptualization: Goutam Kumar Patra; Methodology: Amit Kumar Manna; Software: Dinesh De; Validation: Meman Sahu; Formal Analysis: Meman Sahu; Investigation: Meman Sahu; Resources: Goutam Kumar Patra; Data Curation: Dinesh De; Writing - Original Draft: Goutam Kumar Patra; Writing - Review and Editing: Goutam Kumar Patra; Visualization: Goutam Kumar Patra; Funding acquisition: Goutam Kumar Patra; Supervision: Goutam Kumar Patra; Project Administration: Goutam Kumar Patra. ORCID and Email Meman Sahu memansahu8@gmail.com https://orcid.org/0000-0001-9397-4805 Amit Kumar Manna amitmanna51@gmail.com https://orcid.org/0000-0002-9605-2168 Dinesh De d2chem@gmail.com https://orcid.org/0000-0001-7850-8718 Goutam Kumar Patra goutam.patra@ggu.ac.in https://orcid.org/0000-0003-3151-0284 References [1]. Stratton, W. J.; Busch, D. H. The Complexes of Pyridinaldazine with Iron(II) and Nickel(II). J. Am. Chem. Soc. 1958, 80 (6), 1286–1289. [2]. Stratton, W. J.; Busch, D. H. The Complexes of Pyridinaldazine with Iron(II) and Nickel(II). II. J. Am. Chem. Soc. 1958, 80 (13), 3191–3195. [3]. Stratton, W. J.; Busch, D. H. The Complexes of Pyridinaldazine. III. Infrared Spectra and Continued Synthetic Studies. J. Am. Chem. Soc. 1960, 82 (18), 4834–4839. [4]. Zimmer, M.; Tocher, D. A.; Patra, G. K.; Naskar, J. P.; Datta, D. First Example of a Double Stranded Helicate with Square-Planar Coordination for the Metal. Indian J. Chem. Sect. A 1999, 38, 1087– 1091. [5]. Pal, P. K.; Chowdhury, S.; Purkayastha, P.; Tocher, D. A.; Datta, D. A Novel Double-Stranded Dinuclear Copper(I) Helicate Having a Photoluminescent CuI2N8 Chromophore. Inorg. Chem. Commun. 2000, 3 (11), 585–589. [6]. Stratton, W. J. Metal Complexes with Azine Ligands. II. Iron(II), Cobalt(II), and Nickel(II) Complexes with 2-Pyridyl Methyl Ketazine. Inorg. Chem. 1970, 9 (3), 517–520. [7]. Stratton, W. J.; Rettig, M. F.; Drury, R. F. Metal Complexes with Azine Ligands. I. Ligand Hydrolysis and Template Synthesis in the Iron(II)- 2-Pyridinaldazine System. Inorganica Chim. Acta 1969, 3, 97–102. [8]. Boyd, P. D. W.; Gerloch, M.; Sheldrick, G. M. Crystal Structure of Tris-µ- [2,5-Di(2-Pyridyl)-3,4-Diazahexa-2,4-Diene]-Dicobalt(II) Di[Aquotrichlorozincate(II)] Tetrachlorozincate(II) Tetrahydrate: A Helical Binuclear Cobalt(II) Cation. J. Chem. Soc., Dalton Trans. 1974, No. 10, 1097–1102. [9]. Hamblin, J.; Jackson, A.; Alcock, N. W.; Hannon, M. J. Triple Helicates and Planar Dimers Arising from Silver(i) Coordination to Directly Linked Bis-Pyridylimine Ligands. J. Chem. Soc. 2002, No. 8, 1635. [10]. Pal, S.; Pal, S. Syntheses, Structures and Properties of Trans-Dichloro ruthenium(II) Complexes with N4-Donor Schiff Bases. Polyhedron 2003, 22 (6), 867–873. [11]. Mukherjee, A.; Dutta, A.; Jana, A. D.; Patra, G. K. Copper(I) and Silver(I) Coordination Assemblies of Imino-Pyridyl and Azino-Pyridyl Ligands: Syntheses, Crystal Structures, Spectroscopic and Photophysical Properties. Inorganica Chim. Acta 2013, 404, 131–143. [12]. Mukherjee, A.; Chakrabarty, R.; Ng, S. W.; Patra, G. K. The Syntheses, Characterizations, X-Ray Crystal Structures and Properties of Cu(I) Complexes of a Bis-Bidentate Schiff Base Ligand. Inorganica Chim. Acta 2010, 363 (8), 1707–1712. [13]. Patra, G. K.; Pal, P. K.; Mondal, J.; Ghorai, A.; Mukherjee, A.; Saha, R.; Fun, H.-K. Predesigned Synthesis of Dinuclear to Unusual Hexanuclear to 1D Coordination Polymer of Cu(I)-Halides and Their and Photophysical Properties. Inorganica Chim. Acta 2016, 447, 77–86. [14]. Mondal, J.; Mukherjee, A.; Patra, G. K. CuX (X = I, Br and Cl) Based Coordination Polymers of Azino-Pyridyl Ligand and PPh3: Structural, Spectral, Electro-Chemical, and DFT Studies. Inorganica Chim. Acta 2017, 463, 44–53. [15]. Manna, A. K.; Mondal, J.; Chandra, R.; Rout, K.; Patra, G. K. A Thio-Urea Based Chromogenic and Fluorogenic Chemosensor for Expeditious Detection of Cu2+, Hg2+ and Ag+ Ions in Aqueous Medium. J. Photochem. Photobiol. A Chem. 2018, 356, 477–488. [16]. Patra, G. K.; Goldberg, I.; Chowdhury, S. K.; Maiti, B. C.; Sarkar, A.; Bangal, P. R.; Chakravorti, S.; Chattopadhyay, N.; Tocher, D. A.; Drew, M. G. B.; Mostafa, G.; Chowdhury, S.; Datta, D. A New Photoluminescent CuI2N6 Chromophore. New J. Chem. 2001, 25 (11), 1371–1373. [17]. Patra, G. K.; Goldberg, I.; De, S.; Datta, D. Effect of the Size of Discrete Anions on the Nuclearity of a Complex Cation. CrystEngComm 2007, 9 (9), 828–832. [18]. Patra, G. K.; Goldberg, I. Syntheses and Crystal Structures of Copper and Silver Complexes with New Imine Ligands − Air-Stable, Photoluminescent CuIN4 Chromophores. Eur. J. Inorg. Chem. 2003, 2003 (5), 969–977. [19]. Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J; Howard, J. A. K.; Puschmann, H. OLEX2: a complete structure solution, refinement and analysis program. J. Appl. Cryst. 2009, 42, 339–341. [20]. Sheldrick, G. M. A short history of SHELX. Acta Crystallogr. A 2008, 64, 112–122. [21]. Sheldrick, G. M. Crystal structure refinement with SHELX. Acta Crystallogr. C Struct. Chem. 2015, 71, 3–8. [22]. Norret, M.; Makha, M.; Sobolev, A. N.; Raston, C. L. Controlling the Confinement of Fullerene C60 Molecules Using a Saddle Shape Ni(Ii) Macrocycle. New J. Chem. 2008, 32 (5), 808–812. [23]. Spackman, M. A.; McKinnon, J. J. Fingerprinting Intermolecular Interactions in Molecular Crystals. CrystEngComm 2002, 4 (66), 378– 392. mailto:data_request@ccdc.cam.ac.uk mailto:memansahu8@gmail.com https://orcid.org/0000-0001-9397-4805B mailto:amitmanna51@gmail.com https://orcid.org/0000-0002-9605-2168 mailto:d2chem@gmail.com https://orcid.org/0000-0001-7850-8718 mailto:goutam.patra@ggu.ac.in https://orcid.org/0000-0003-3151-0284 Sahu et al. / European Journal of Chemistry 13 (1) (2022) 1-7 7 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.1.1-7.2166 [24]. Meng, X. X. Applications of Hirshfeld surfaces to ionic and mineral crystals, Ph.D. Thesis, University of New England, 2004. [25]. Pendás, A. M.; Luaña, V.; Pueyo, L.; Francisco, E.; Mori-Sánchez, P. Hirshfeld Surfaces as Approximations to Interatomic Surfaces. J. Chem. Phys. 2002, 117 (3), 1017–1023. [26]. Desiraju, G. R. Crystal Engineering: A Holistic View. Angew. Chem. Int. Ed. Engl. 2007, 46 (44), 8342–8356. [27]. McKinnon, J. J.; Fabbiani, F. P. A.; Spackman, M. A. Comparison of Polymorphic Molecular Crystal Structures through Hirshfeld Surface Analysis. Cryst. Growth Des. 2007, 7 (4), 755–769. [28]. Schmidt, G. M. J. Photodimerization in the Solid State. Pure Appl. Chem. 1971, 27 (4), 647–678. [29]. Wolff, S. K.; Grimwood, D. J.; McKinnon, J. J.; Turner, M. J.; Jayatilaka, D.; Spackman, M. A. CrystalExplorer (Version 3.1), University of Western Australia, 2012. Copyright © 2022 by Authors. This work is published and licensed by Atlanta Publishing House LLC, Atlanta, GA, USA. The full terms of this license are available at http://www.eurjchem.com/index.php/eurjchem/pages/view/terms and incorporate the Creative Commons Attribution-Non Commercial (CC BY NC) (International, v4.0) License (http://creativecommons.org/licenses/by-nc/4.0). By accessing the work, you hereby accept the Terms. This is an open access article distributed under the terms and conditions of the CC BY NC License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited without any further permission from Atlanta Publishing House LLC (European Journal of Chemistry). No use, distribution or reproduction is permitted which does not comply with these terms. Permissions for commercial use of this work beyond the scope of the License (http://www.eurjchem.com/index.php/eurjchem/pages/view/terms) are administered by Atlanta Publishing House LLC (European Journal of Chemistry). http://www.eurjchem.com/index.php/eurjchem/pages/view/terms http://creativecommons.org/licenses/by-nc/4.0 http://www.eurjchem.com/index.php/eurjchem/pages/view/terms 1. Introduction 2. Experimental 2.1. Materials and physical measurements 2.2. Synthesis of the ligand,1,2-bis(pyridin-2-ylmethylene) hydrazine (L) 2.3. Synthesis of nickel(II) perchlorate complex (1) 2.4. X-ray crystallography 2.5. Hirshfeld surface calculations 3. Results and discussion 3.1. Synthetic aspects 3.2. Structural description of complex 1 3.3. Theoretical investigations 4. Conclusion Supporting information Disclosure statement CRediT authorship contribution statement ORCID and Email References PrintField10: PrintField11: PrintField12: PrintField13: PrintField14: PrintField15: PrintField16: PrintField20: PrintField21: PrintField22: PrintField23: PrintField24: PrintField25: PrintField26: