Ring Motif Research Articles

Synthesis, crystal structure determination and Hirshfeld surface analysis of three new salt forms of creatinine with hydrobromic acid, 3-aminobenzoic acid and 3,5-dinitrobenzoic acid.

Creatinine, a biologically important compound, is used to analyze kidney function and kidney diseases in the human body. The salt form of creatinine is used in the formation of drug materials like anti-HIV, antifungal, antiprotozoal, antiviral and antitumour compounds. Here we report the solid-state structures of three new crystalline salts, namely, creatininium (2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium) bromide, C4H8N3O+·Br-, (I), creatininium 3-aminobenzoate, C4H8N3O+·C7H6NO2-, (II), and creatininium 3,5-dinitrobenzoate, C4H8N3O+·C7H3N2O6-, (III). These salts have been synthesized and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. The structural chemistry of salts (I)-(III) and their crystal packing are discussed in detail. The primary interaction between the creatinine cation and the acid anion in the three salts is N-H...Br/O hydrogen bonds. In salt (I), the creatinine cation and bromide anion are connected through a pair of N-H...Br hydrogen bonds forming R42(8) and R42(12) ring motifs. In salts (II) and (III), the creatinine cation interacts with the corresponding anion via a pair of N-H...O hydrogen bonds. The crystal structure is further stabilized by C-H...O and O-H...O hydrogen bonds with the ring motifs R22(8), R21(7) and R21(6). Furthermore, the crystal structures are stabilized by π-π, C-H...π, C-O...π and N-O...π stacking interactions. The contributions made by each hydrogen bond in maintaining the crystal structure stability has been quantified by Hirshfeld surface analysis.

Co-crystallisation of 4-amino pyridine with succinic acid (1:1): spectroscopic, thermal, crystal structure, DFT/HF calculation and Hirshfeld surface analysis

ABSTRACT Slow evaporation procedure yielded the co-crystal of 4-amino pyridine:Succinic acid (1:1). Thermal (TGA/DSC), FT-IR spectroscopic and single crystal X-ray diffraction (SCXRD) studies were performed to elucidate the structure and chemical characteristics. The SCXRD investigation reveals that the crystal packing is mainly strengthen by O–H···O, O–H···N, N–H···O and comparatively weak C–H···O hydrogen bonding between the 4-amino pyridine and succinic acid and further stabilised by (11) ring motif and weak C–O···π and π–π interaction. The optimised parameters and Mulliken charges have been investigated using density functional theory (DFT) as well as Hartree–Fock (HF) techniques (with hybrid B3LYP/6-311++G(d, p)). The molecular electrostatic potential (MSP), frontier molecular orbitals, reactivity characteristics, and the Hirshfeld surface (HS) analysis were performed. The analysis reveals that the N–H···O, O–H···N, O–H···O and C–H···O hydrogen bond interactions are the key contributors to intermolecular stabilisation in the co-crystal.

Crystal structure and Hirshfeld surface analysis of 2,2'-(phenyl-aza-nedi-yl)bis-(1-phenyl-ethan-1-one).

The whole mol-ecule of the title compound, C22H19NO2, is generated by twofold rotational symmetry. The N atom exhibits a trigonal-planar geometry and is located on the twofold rotation axis. In the crystal, mol-ecules are linked by C-H⋯O contacts with R 2 2(12) ring motifs, and C-H⋯π inter-actions, resulting in ribbons along the c-axis direction. van der Waals inter-actions between these ribbons consolidate the mol-ecular packing. Hirshfeld surface analysis indicates that the greatest contributions to the crystal packing are from H⋯H (45.5%), C⋯H/H⋯C (38.2%) and O⋯H/H⋯O (16.0%) inter-actions.

Structural-property relationship in halogen-bonded Schiff base derivative: Crystal structure, computational and SARS-CoV-2 docking studies

We synthesized the halogenated Schiff base compound to understand the influence of halogen and hydrogen bonding interactions. The Schiff base compound is characterized by FTIR, SEM-EDAX and single-crystal X-ray diffraction studies. The structural studies reveal that the 4-chloro-2-(((4-chlorobenzyl) imino) methyl) phenol crystallizes in the monoclinic, P21/n space group. The O1-H1‧‧‧N1 strong hydrogen bond forms the intramolecular pseudo chelating ring motif and acts as a coordinating site for metal complexes. The intra, intermolecular and π‧‧‧π interactions were involved in the construction of supramolecular architecture. The interesting type-I halogen bonds having trans geometry are exhibited. Hirshfeld surface analysis supports the interactions observed in the crystal structure, and the energy framework analysis provides the stabilization interaction energy among the molecular pairs. The enrichment ratio provides favored contacts between the atomic pair and gives strong validation to the halogen‧‧‧halogen and halogen‧‧‧hydrogen bonds. The DFT studies give more insight into electronic structure and provide a global and local parameter of the molecule. NBO studies provide stabilization energy and charge transfer within the molecule. The QTAIM studies were used to calculate the strength of the halogen, hydrogen and stacking intermolecular interaction. Further, docking studies were carried out for COVID-19 proteins to reveal the structural-function properties of halogen and hydrogen bonds present in the synthesized compound.

Crystal structures and Hirshfeld surface analyses of hypoxanthine salts involving 5-sulfosalicylate and perchlorate anions.

Two salts of 1,9-di-hydro-purin-6-one (hypoxanthine), namely, 6-oxo-1,9-di-hydro-purin-7-ium 5-sulfosalicylate dihydrate, C5H5N4O+·C7H5O6S-·2H2O, (I), and 6-oxo-1,9-di-hydro-purin-7-ium perchlorate monohydrate, C5H5N4O+·ClO4 -·H2O, (II), have been synthesized and characterized using single-crystal X-ray diffraction and Hirshfeld analysis. In both salts, the hypoxanthine mol-ecule is protonated at the N7 position of the purine ring. In salt (I), the cation and anion are connected through N-H⋯O inter-actions. The protonated hypoxanthine cations of salt (I) form base pairs with another symmetry-related hypoxanthine cation through N-H⋯O hydrogen bonds with an R 2 2(8) ring motif, while in salt (II), the hypoxanthine cations are paired through a water mol-ecule via N-H⋯O and O-H⋯N hydrogen bonds with an R 3 3(11) ring motif. The packings within the crystal structures are stabilized by π-π stacking inter-actions in salt (I) and C-O⋯π inter-actions in salt (II). The combination of several inter-actions leads to the formation of supra-molecular sheets extending parallel to (010) in salts (I) and (II). Hirshfeld surface analysis and fingerprint plots reveal that O⋯H/H⋯O contacts play the major role in the crystal packing of each of the salts, with a 54.1% contribution in salt (I) and 62.3% in salt (II).

Formation of Salts and Molecular Ionic Cocrystals of Fluoroquinolones and α,ω-Dicarboxylic Acids.

The cocrystallization of the fluoroquinolones ciprofloxacin (cip), norfloxacin (nor), and enrofloxacin (enro) with the α,ω-dicarboxylic acids glutaric acid (glu), adipic acid (adi), pimelic acid (pim), suberic acid (sub), azeliac acid (az), and sebacic acid (seb) resulted in 27 new molecular salts and ternary molecular ionic cocrystals of compositions A+B–, A2+B2–, A2+B2–B, and A+B–A. Depending on the solvent, different stoichiomorphs, solvates, or polymorphs were obtained. All salts and cocrystals contain the robust R2NH2+...–OOC or R3NH+...–OOC synthon but have different supramolecular ring motifs. Moderate solubility enhancements over the parent fluoroquinolones were observed. Salts in the ratio of 1:1 and 2:1 were also prepared by ball-milling. The milled sample nor/az (1:1) was shown to gel the GRAS (generally recognized as safe) solvent propylene glycol, and enro/sub (1:1) was shown to gel both propylene glycol and water. Dynamic rheology measurements confirmed that nor/az and enro/sub behave like viscoelastic materials and supramolecular gels.

Novel supramolecular co-crystal of 3-aminobenzoic acid with 4-acetyl-pyridine: Synthesis, X-ray structure, DFT and Hirshfeld surface analysis

A novel co-crystal of 3-aminobenzoic acid with 4-acetyl pyridine (ABA:AP) has been synthesized and its structure determined by single crystal X-ray diffraction (SCXRD) methods. It crystallizes in the monoclinic crystal system with space group P21/n and unit cell parameters a = 7.573(11) Å, b = 10.718(11) Å, c = 15.77(2) Å, β = 98.10(10)°, Z = 4. The co-crystal is stabilized by R22(8) ring motif, hydrogen bonding and π-π interactions. Density functional theory (DFT) and Hartree Fock (HF) methods with basis set of B3LYP/6-311+G(d,p) have been employed to obtain the optimized structural geometry, Mulliken charges, molecular electrostatic potential (MSP) and frontier molecular orbitals. The contribution of distinct interactions within the molecule and the strength of molecular packing in the co-crystal have been investigated by Hirshfeld surface (HS) analysis.

Crystal structure and Hirshfeld surface analysis of 7,7-dimethyl-2-phenyl-3,3a,4,6,7,8,9,9a-octa-hydro-1H-benzo[f]iso-indole-1,5(2H)-dione.

The title compound, C20H23NO2, was obtained via the reaction of N-allyl-N-phenyl-acryl-amide with 3-iodo-cyclo-hex-2-en-1-one using PdCl2(PPh3)2 as a catalyst. The compound crystallizes in the monoclinic space group P21/c. The fused-ring system is not planar and the five- and six-membered rings are trans-fused. The mol-ecular geometry is partially stabilized by an intra-molecular C-H⋯O hydrogen bond, forming an S(6) ring motif. In the crystal, mol-ecules are linked by C-H⋯O and C-H⋯π inter-actions into a three-dimensional network. To further analyse the inter-molecular inter-actions, a Hirshfeld surface analysis was performed. The results indicate that the most important contributions to the overall surface are from H⋯H (65.5%), O⋯H/H⋯O (17.5%) and C⋯H/H⋯C (14.3%) inter-actions.

Structure, charge density, and Hirshfeld surface analysis of proton transfer complex 2‐amino‐4‐methylpyridinium 2‐(3‐methylphenyl)‐acetate

AbstractThe compounds m‐Tolylacetic acid and 2‐amino‐4‐Picoline were used as a precursor to synthesize the molecular complex 2‐amino‐4‐methylpyridinium 2‐(3‐methylphenyl)‐acetate by means of proton transfer. High‐resolution X‐ray diffraction data were collected for the crystallized complex at 100 K. The structure was solved spherically and further an aspherical model refinement was performed using Hansen and Coppens multipole formalism. Topological properties using AIM analysis were carried out for the title compound to understand the atom–atom interactions and the strength of the bond. The structure exhibits interesting patterns of N–H…O and C–H…O hydrogen bonds. A pair of N–H…O hydrogen bonds links the anion and cation of the molecular complex generating an R22(8) ring motif. These ring motifs are linked to adjacent anions and cations through another intermolecular N–H…O hydrogen bond generating a bifurcated R22(8)ring motif. Hirshfeld surface analysis was carried out to understand the types of inter‐molecular interactions and their strengths.

Crystal structure and Hirshfeld surface analysis of dimethyl 3,3'-{[(1E,2E)-ethane-1,2-diyl-idene]bis(aza-nylyl-idene)}bis-(4-methyl-benzoate).

The title Schiff base compound, C20H20N2O4, synthesized by the condensation reaction of methyl 3-amino-4-methyl-benzoat and glyoxal in ethanol, crystallizes in the the monoclinic space group P21/n. The mol-ecule is Z-shaped with the C-N-C-C torsion angle being 47.58 (18)°. In the crystal, pairs of mol-ecules are linked via C-H⋯N hydrogen bonds, forming centrosymetric dimers with an R 2 2(8) ring motif; this connectivity leads to the formation of columns running along the a-axis direction. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to explore the inter-molecular inter-actions and revealed that the most significant contributions to the crystal packing are from H⋯H (49.4%), H⋯O/O⋯H (19.0%) and H⋯C/C⋯H (17.5%) contacts. Energy frameworks were constructed through different inter-molecular inter-action energies to investigate the stability of the compound. The net inter-action energies for the title compound were found to be electrostatic (E ele = -48.4 kJ mol-1), polarization (E pol = -9.7 kJ mol-1), dispersion (E dis = -186.9 kJ mol-1) and repulsion (E rep = 94.9 kJ mol-1) with a total inter-action energy, E tot, of -162.4 kJ mol-1.

Crystal structures and Hirshfeld surface analysis of 5-amino-1-(4-meth-oxy-phen-yl)pyrazole-4-carb-ox-ylic acid and 5-amino-3-(4-meth-oxy-phen-yl)isoxazole.

The title compounds, C11H11N3O3, (I), and C10H10N2O2, (II), are commercially available and were crystallized from ethyl acetate solution. The dihedral angle between the pyrazole and phenyl rings in (I) is 52.34 (7)° and the equivalent angle between the isoxazole and phenyl rings in (II) is 7.30 (13)°. In the crystal of (I), the mol-ecules form carb-oxy-lic acid inversion dimers with an R(8) ring motif via pairwise O-H⋯O hydrogen bonds. In the crystal of (II), the mol-ecules are linked via N-H⋯N hydrogen bonds forming chains propagating along [010] with a C(5) motif. A weak N-H⋯π inter-action also features in the packing of (II). Hirshfeld surface analysis was used to explore the inter-molecular contacts in the crystals of both title compounds: the most important contacts for (I) are H⋯H (41.5%) and O⋯H/H⋯O (22.4%). For (II), the most significant contact percentages are H⋯H (36.1%) followed by C⋯H/H⋯C (31.3%).

Growth, structural, optical, Z-scan and dielectric analysis of 2-Amino-4-methylpyridinium 2-chloro 4-nitro benzoate crystals for third order non-linear optical applications

• AMPCNB was synthesized and grown as crystal by slow evaporation method. The centrosymmetric space group of AMPCNB was concluded as P21/n. • The lower cut-off wavelength of AMPCNB was found to be 318 nm and band gap energy gap was 3.16 eV. • The NLO parameters, refractive index (n2) = 5.610 × 10−8 cm2/W and absorption coefficient = 0.033 × 10−4 cm/W were found. • The dielectric study reveals the phase transition at high temperature. An organic nonlinear optical material 2-Amino-4-methylpyridinium 2-chloro 4-nitro benzoate (AMPCNB) was synthesized and large size single crystals were grown by slow evaporation solution growth method. Single crystal X-ray diffraction study showed that the title compound belongs to monoclinic crystal system with P2 1 /n space group. In the title molecular salt, C 6 H 9 N 2 + ·C 7 H 3 ClNO 4 − , the original pyridine N atom of 2-amino-4-methylpyridine is protonated. The chloro and the carboxylic acid group of nitrobenzoic acid is deprotonated. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxylate O atoms of the anion via a pair of N-H···O hydrogen bonds, forming a R 2 2 (8) ring motif. The ion pairs are further connected via N-H···O and C-H···O hydrogen bonds. The molecules are further stabilized by C-H···π and π-π interactions. The UV–VIS-NIR study was performed to investigate the transparency window and lower cutoff wavelength of the compound. The third harmonic efficiency of title compound has been studied using Z-scan technique using continuous wave Nd:YAG laser to confirm its saturable absorption and self-defocusing effect. Theoretical calculation of molecular polarizability, which is helpful in device fabrication, was carried out from Penn gap, Clausius-Mossotti equations and the obtained results were compared. The Vickers’ micro hardness test was carried out at room temperature and obtained results were investigated using classical Meyer's law.

Crystal structure and Hirshfeld surface analysis of 2-amino-4-(4-meth-oxy-phen-yl)-6-oxo-1-phenyl-1,4,5,6-tetra-hydro-pyridine-3-carbo-nitrile.

The central tetra-hydro-pyridine ring of the title compound, C19H17N3O2, adopts a screw-boat conformation. In the crystal, strong C-H⋯O and N-H⋯N hydrogen bonds form dimers with R 2 2(14) and R 2 2(12) ring motifs, respectively, between consecutive mol-ecules along the c-axis direction. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonds connect these dimers, forming a three-dimensional network. C-H⋯π inter-actions and π-π stacking inter-actions contribute to the stabilization of the mol-ecular packing. A Hirshfeld surface analysis indicates that the contributions from the most prevalent inter-actions are H⋯H (47.1%), C⋯H/H⋯C (20.9%), O⋯H/H⋯O (15.3%) and N⋯H/H⋯N (11.4%).

Crystal structure of (7-{[bis-(pyridin-2-ylmeth-yl)amino-κ3 N,N',N'']meth-yl}-5-chloro-quinolin-8-ol)di-bromidozinc(II).

In the title compound, [ZnBr2(C22H19ClN4O)], the ZnII atom adopts a distorted square-pyramidal coordination geometry, formed by two bromido ligands and three N atoms of the bis-(pyridin-2-ylmeth-yl)amine moiety in the penta-dentate ligand containing quinolinol. The ZnII atom is located well above the mean basal plane of the square-based pyramid. The apical position is occupied by a Br atom. The O and N atoms of the quinolinol moiety in the ligand are not coordinated to the ZnII atom. An intra-molecular O-H⋯N hydrogen bond, generating an S(5) ring motif, stabilizes the mol-ecular structure. In the crystal, the mol-ecules are linked by inter-molecular C-H⋯Br hydrogen bonds, generating ribbon structures containing alternating R 2 2(22) and R 2 2(14) rings. These ribbons are linked through an inter-molecular C-H⋯Br hydrogen bond, forming a two-dimensional network sheet.

Crystal structure and Hirshfeld surface analysis of 5-acetyl-2-amino-4-(4-bromo-phen-yl)-6-oxo-1-phenyl-1,4,5,6-tetra-hydro-pyridine-3-carbo-nitrile.

The crystal structure of the title compound, C20H16BrN3O2, was determined using an inversion twin. Its asymmetric unit comprises two crystallographically independent mol-ecules (A and B) being the stereoisomers. Both mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming a dimer with an R 2 2(16) ring motif. The dimers are connected by further N-H⋯O and N-H⋯N hydrogen bonds, forming chains along the c-axis direction·C-Br⋯π inter-actions between these chains contribute to the stabilization of the mol-ecular packing. Hirshfeld surface analysis showed that the most important contributions to the crystal packing are from H⋯H, C⋯H/H⋯C, O⋯H/H⋯O, Br⋯H/H⋯Br and N⋯H/H⋯N inter-actions.

Synthesis, crystal structure, molecular docking, lattice energy and Hirshfeld surface analysis of an antituberculosis drug of (E)-2-methoxy-5-(((6-methoxypyridin-3yl)imino)methyl)phenol

Synthesis, X-ray structure, molecular docking, lattice energy and Hirshfeld surface analysis of (E)-2-methoxy-5-(((6-methoxypyridin-3yl)imino)methyl)phenol (MMPIMP) is presented in this paper. The compound crystallizes in the monoclinic space group P21/c with unit cell parameters: a = 5.6149 (2), b = 14.5520 (5), c = 29.9813 (8) Å, β = 94.795 (3) and Z = 8. The asymmetric unit contains two crystallographically independent molecules (A and B) and the structure was solved by direct methods using single-crystal X-ray diffraction data and refined by full-matrix least-squares procedure to a final value of R = 0.050 and wR2 = 0.1231 for 3536 observed reflections. The molecular packing in the unit cell is stabilized via O – H… N and C – H… O intermolecular hydrogen bonds. In the crystal packing, pairs of intermolecular hydrogen bonds of the type O–H…N links the molecules into dimers, forming R 2 2 (20) ring motif. To understand the nature and strength of intermolecular interaction in terms of its energy and their quantitative contributions toward the molecular packing, lattice energy analysis was carried out by using PIXEL software. Molecular docking studies were executed to realize the inhibitory activity of the compound MMPIMP against DprE1 (PDB code: 4KW5). The analysis of the Hirshfeld surface and its associated two dimension fingerprint plots has been carried out to examine the intermolecular contacts in the crystal structure.

Crystal structure, Hirshfeld, computational biomolecular investigations, and MTT assay studies of amino pyrimidine derivative as EGFR kinase domain inhibitor

A nitrogen heterocyclic pyrimidine fused heterocyclic derivative 4-(4-Methoxyphenyl)-6-(2-phenylethyl)pyrimidin-2-amine (MPPPA), was synthesized and crystal structure is identified by single crystal XRD method. The asymmetric structure of MPPPA belongs to orthorhombic (Pna21) space group with unit cell parameters a = 14.6720(7) Å, b = 14.3922(6) Å, c = 7.6334(3) Å, α=β=γ= 90° and Z = 4. Two inter­molecular N3-H3A···N1i, N3-H3B···N2ii hydrogen bonds that fomrs R22(8) ring motifs in zigzag format that run along c-axis is noticed in supramolecular network of MPPPA crystal structure. The optimized structure of the compound is investigated using density functional theory (DFT). Energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) with other global reactivity parameters are computed. Further, surface map of molecular electrostatic potential (MEP) is determined using the electron density of the compound to recognize the reactivity region of our compound. To understand the supramolecular features, the close contacts of the molecular crystal of the complex is evaluated using Hirshfeld surface analysis by CrystalExplorer 17.5 program. Enrichment ratio is calculated to find the propensity of the intermolecular contacts in building the crystal packing. Bioactivity score, drug-likeness and ADMET properties of the compound is analysed to determine its potential bioactivity. In-silico molecular docking was performed to examine the EGFR inhibition of the MPPPA compound as a potential anticancer agent by docking with Crystal structure of EGFR kinase domain protein (PDB ID: 2J6M) using PyRx program. The MPPPA ligand is docked with 2J6M protein by three conventional N-H…O type hydrogen bonds, one C-H…O hydrogen bond, and various hydrophobic bonds with docking energy = -9.8 kcal/mol. Further, anticancer activity of MPPPA was investigated against lung cancer (A549), cervical cancer (HeLa) and liver cancer (Hep3b) cell lines and compared with activity of standard drug Gefitinib. In vitro results showed higher cytotoxicity of MPPPA with A549 cells and could be treated as lead molecule for lung cancer drug design.

Crystal structure and Hirshfeld surface analysis of (Z)-4-{[4-(3-methyl-3-phenyl-cyclo-but-yl)thia-zol-2-yl]amino}-4-oxobut-2-enoic acid.

The title cyclo-butyl compound, C18H18N2O3S, was synthesized by the inter-action of 4-(3-methyl-3-phenyl-cyclo-but-yl)thia-zol-2-amine and maleic anhydride, and crystallizes in the ortho-rhom-bic space group P212121 with Z' = 1. The mol-ecular geometry is partially stabilized by an intra-molecular N-H⋯O hydrogen bond forming an S 1 1(7) ring motif. The mol-ecule is non-planar with a dihedral angle of 88.29 (11)° between the thia-zole and benzene rings. In the crystal, the mol-ecules are linked by O-H⋯N hydrogen bonds, forming supra-molecular ribbons with C 1 1(9) chain motifs. To further analyze the inter-molecular inter-actions, a Hirshfeld surface analysis was performed. The results indicate that the most important contributions to the overall surface are from H⋯H (43%), C⋯H (18%), O⋯H (17%) and N⋯H (6%), inter-actions.

Crystal structure and Hirshfeld surface analysis of 6,6'-((1E,1'E)-{[1,4-phenyl-enebis(methyl-ene)]bis(aza-nylyl-idene)}bis-(methane-ylyl-idene))bis-(2-meth-oxy-phenol).

The Schiff base compound, C24H24N2O4, was synthesized by the inter-action of 2-hy-droxy-3-meth-oxy benzaldehyde and 1,4-benzene dimethanamine in ethanol, and crystallizes in the monoclinic space group P21/n with Z' = 0.5. The mol-ecule is not planar, the 1,4-di-ethyl-benzene and the phenol rings are twisted with respect to each other, making a dihedral angle of 74.27 (5)°. The mol-ecular structure is stabilized by an O-H⋯N hydrogen bond, forming an S(6) ring motif. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, resulting in the formation of sheets parallel to the bc plane. A Hirshfeld surface analysis was undertaken to investigate the various inter-molecular contacts controlling the supra-molecular topology, suggesting the H⋯O (18%) contacts to be the most significant inter-actions, whereas the H⋯H (50.5%) and C⋯H (24.3%) inter-actions are less significant.

Crystal structure, Hirshfeld surface analysis and DFT study of 2,2''-({[(1E,1'E)-(diselanedi-yl)bis-(2,1-phenyl-ene)]bis-(methane-ylyl-idene)}bis-(aza-neylyl-idene))bis-[3',6'-bis-(di-ethyl-amino)-4a',9a'-di-hydro-spiro-[isoindoline-1,9'-xanthen]-3-one

The title compound, C70H70N8O4Se2, is a spiro bicyclic diselenide, made up of two [SeC6H4CH=N-N(CO)C6H4(C)C6H3NEt2(O)C6H3NEt2] units related by a twofold crystallographic symmetry element bis-ecting the diselenide bond. The compound crystallizes in a non-centrosymmetric polar space group (tetra-gonal, P b2) and the structure was refined as an inversion twin. The two diethyl amine groups and their attached phenyl groups of the xanthene ring are disordered over two orientations, with occupancies of 0.664 (19)/0.336 (19) and 0.665 (11)/0.335 (11), respectively. The dihedral angles between the mean planes of the central isoindoline and the phenyl rings are 26.8 (2) and 2.5 (4)°, respectively. The mean plane of the central xanthene ring forms dihedral angles of 2.0 (5), 8.8 (5), 1.7 (5) and 7.9 (6)° with the peripheral phenyl rings. The isoindoline and xanthene rings subtend a dihedral angle of 89.8 (2)°. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯O hydrogen bond generating an S(6) ring motif. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds together with C-H⋯π (ring) inter-actions, forming a three-dimensional network. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (68.1%), C⋯H/H⋯C (21.2%) and O⋯H/H⋯O (8.7%) contacts. The optimized structure calculated using density functional theory (DFT) at the B3LYP/6 - 31 G(d) level is compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was used to determine the energy gap and the mol-ecular electrostatic potential (MEP) of the compound was investigated.