Quantitative analysis of intermolecular interactions in orthorhombic rubrene

Syntheses, crystal structures, Hirshfeld surface analyses and crystal voids of 1-(4-bromo-phen-yl)-2,2-di-chloro-ethan-1-one and 2,2-di-bromo-1-(p-tol-yl)ethan-1-one

The asymmetric units of the compounds, C8H5BrCl2O (I), and C9H8Br2O (II), contain two and one crystallographically independent mol-ecules, respectively. In compound (I), the planar rings are oriented at a dihedral angle of 13.23 (8)°. In crystals of both compounds, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into infinite chains along the b-axis direction. In crystal of (I), there are π-π inter-actions between the centroids of the parallel rings with centroid-to-centroid distances of 3.5974 (14), 3.6178 (16) and 3.9387 (16) Å while neither π-π nor C-H⋯ π(ring) inter-actions are present in (II). The Hirshfeld surface analyses of the crystal structures indicate that the most important contributions for the crystal packings are from H⋯Cl/Cl⋯H (27.5%), H⋯O/O⋯H (15.0%), H⋯Br/Br⋯H (10.2%) and H⋯H (9.0%) for (I) and H⋯Br/Br⋯H (36.1%), H⋯H (22.2%), H⋯O/O⋯H (14.1%) and H⋯C/C⋯H (13.9%) for (II). Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packings. The volumes of the crystal voids and the percentages of free spaces in the unit cells were calculated to 111.55 Å3 and 12.27% for (I) and 63.37 Å and 6.69% for (II), showing that no large cavities are present in either structure.

Crystal structure, Hirshfeld surface analysis and crystal voids of 4-nitro-benzo[c][1,2,5]selena-diazole

The title mol-ecule, C6H3N3O2Se, is almost planar. In the crystal, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into a network structure, enclosing R 2 2(7) and R 3 3(8) ring motifs, parallel to the bc plane. There are π-π inter-actions present with centroid-to-centroid distances of 3.746 (3) and 3.697 (3) Å. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯O/O⋯H (19.6%), H⋯N/N⋯H (11.0%), H⋯Se/Se⋯H (8.5%), O⋯Se/Se⋯O (8.2%), H⋯H (7.4%), C⋯N/N⋯C (7.3%) and N⋯Se/Se⋯N (7.2%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 25.60 Å3 and 3.73%, showing that there is no large cavity in the crystal.

Synthesis, crystal structure and Hirshfeld surface analysis of 5-oxo-N-phenyl-3-(thio-phen-2-yl)-2,3,4,5-tetra-hydro-[1,1'-biphen-yl]-4-carboxamide

The asymmetric unit of the title com-pound, C23H19NO2S, contains two mol-ecules that differ in the conformation of the two carb-ox-amide moieties. In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains propagating parallel to the c-axis direction. Between the mol-ecules, weak C-H⋯π(ring) inter-actions are present, whereas π-π inter-actions are not observed. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (47.6%), H⋯C/C⋯H (33.4%) and H⋯O/O⋯H (11.6%) inter-actions. Orientational disorder is observed for both thio-phene rings.

Crystal structure and Hirshfeld surface analysis of supra-molecular aggregate of 2,2,6,6-tetra-methyl-piperidin-1-ium bromide with 1,2,3,4-tetra-fluoro-5,6-di-iodo-benzene

The asymmetric unit of the title compound, C9H20N+·Br-·C6F4I2, contains one 2,2,6,6 tetra-methyl-piperidine-1-ium cation, one 1,2,3,4-tetra-fluoro-5,6-di-iodo-benzene mol-ecule, and one uncoordinated bromide anion. In the crystal, the bromide anions link the 2,2,6,6-tetra-methyl-piperidine mol-ecules by inter-molecular C-H⋯Br and N-H⋯Br hydrogen bonds, leading to dimers, with the coplanar 1,2,3,4-tetra-fluoro-5,6-di-iodo-benzene mol-ecules filling the space between them. There is a π-π interaction between the almost parallel benzene rings [dihedral angle = 10.5 (2)°] with a centroid-to-centroid distance of 3.838 (3) Å and slippage of 1.468 Å. No C-H⋯π(ring) inter-actions are observed. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯F/F⋯H (23.8%), H⋯H (22.6%), H⋯Br/Br⋯H (17.3%) and H⋯I/I⋯H (13.8%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing.

Crystal structure and Hirshfeld surface analyses, crystal voids, inter-molecular inter-action energies and energy frameworks of 3-benzyl-1-(3-bromoprop-yl)-5,5-di-phenyl-imidazolidine-2,4-dione

The title mol-ecule, C25H23BrN2O2, adopts a cup shaped conformation with the distinctly ruffled imidazolidine ring as the base. In the crystal, weak C-H⋯O hydrogen bonds and C-H⋯π(ring) inter-actions form helical chains of mol-ecules extending along the b-axis direction that are linked by additional weak C-H⋯π(ring) inter-actions across inversion centres. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (51.0%), C⋯H/H⋯C (21.3%), Br⋯H/H⋯Br (12.8%) and O⋯H/H⋯O (12.4%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated to be 251.24 Å3 and 11.71%, respectively, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated by the dispersion energy.

On the importance of crystal structures for organic thin film transistors

Historically, knowledge of the molecular packing within the crystal structures of organic semiconductors has been instrumental in understanding their solid-state electronic properties. Nowadays, crystal structures are thus becoming increasingly important for enabling engineering properties, understanding polymorphism in bulk and in thin films, exploring dynamics and elucidating phase-transition mechanisms. This review article introduces the most salient and recent results of the field.

Bifonazole caffeate: The first molecular salt of bifonazole with enhanced biopharmaceutical property based on experiments and quantum chemistry research

In order to make novel breakthroughs in molecular salt studies of BCS class-IV antifungal medication bifonazole (BIF), a salification-driven strategy towards ameliorating attributes and aiding augment efficiency is raised. This strategy fully harnesses structural characters together attributes and benefits of caffeic acid (CAF) to concurrently enhance dissolvability and permeability of BIF by introducing the two ingredients into the identical molecular salt lattice through the salification reaction, which, coupled with the aroused potential activity of CAF significantly amplifies the antifungal efficacy of BIF. Guided by this route, the first BIF-organic molecular salt, BIF-CAF, is directionally designed and synthesized with satisfactorily structural characterizations and integrated theoretical and experimental explorations on the pharmaceutical properties. Single-crystal X-ray diffraction resolving confirms that there is a lipid-water amphiphilic sandwich structure constructed by robust charge-assistant hydrogen bonds in the salt crystal, endowing the molecular salt with the potential to enhance both dissolvability and permeability relative to the parent drug, which is validated by experimental evaluations. Remarkably, the comprehensive DFT-based theoretical investigations covering frontier molecular orbital, molecular electrostatic potential, Hirshfeld surface analysis, reduced density gradient, topology, sphericity and planarity analysis strongly support these observations, thereby allowing some positive relationships between macroscopic properties and microstructures of the molecular salt can be made. Intriguingly, the optimal properties, together with the stimulated activity of CAF markedly augment in vitro antifungal ability of the molecular salt, with magnifying inhibition zones and reducing minimum inhibitory concentrations. These findings fill in the gaps on researches of BIF-organic molecular salt, and adequately exemplify the feasibility and validity by integrating theoretical and experimental approaches to resolve BIF's problems via the salification-driven tactic.

Crystal structure, Hirshfeld surface analysis, and calculations of inter-molecular inter-action energies and energy frameworks of 1-[(1-hexyl-1H-1,2,3-triazol-4-yl)meth-yl]-3-(1-methyl-ethen-yl)-benzimidazol-2-one

The benzimidazole moiety in the title mol-ecule, C19H25N5O, is almost planar and oriented nearly perpendicular to the triazole ring. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules into a network structure. There are no π-π inter-actions present but two weak C-H⋯π(ring) inter-actions are observed. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (62.0%), H⋯C/C⋯H (16.1%), H⋯N/N⋯H (13.7%) and H⋯O/O⋯H (7.5%) inter-actions. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via the dispersion energy contributions in the title compound.

Crystal structure, Hirshfeld surface analysis, DFT and the mol-ecular docking studies of 3-(2-chloro-acet-yl)-2,4,6,8-tetra-phenyl-3,7-di-azabicyclo-[3.3.1]nonan-9-one

In the title compound, C33H29ClN2O2, the two piperidine rings of the di-aza-bicyclo moiety adopt distorted-chair conformations. Inter-molecular C-H⋯π inter-actions are mainly responsible for the crystal packing. The inter-molecular inter-actions were qu-anti-fied and analysed using Hirshfeld surface analysis, revealing that H⋯H inter-actions contribute most to the crystal packing (52.3%). The mol-ecular structure was further optimized by density functional theory (DFT) at the B3LYP/6-31 G(d,p) level and is compared with the experimentally determined mol-ecular structure in the solid state.

Crystal structure, Hirshfeld surface analysis, DFT optimized mol-ecular structure and the mol-ecular docking studies of 1-[2-(cyano-sulfan-yl)acet-yl]-3-methyl-2,6-bis-(4-methyl-phen-yl)piperidin-4-one

The two mol-ecules in the asymmetric unit of the title compound, C23H24N2O2S, have a structural overlap with an r.m.s. deviation of 0.82 Å. The piperidine rings adopt a distorted boat conformation. Intra- and inter-molecular C-H⋯O hydrogen bonds are responsible for the cohesion of the crystal packing. The inter-molecular inter-actions were qu-anti-fied and analysed using Hirshfeld surface analysis. The mol-ecular structure optimized by density functional theory (DFT) at the B3LYP/6-311++G(d,p)level is compared with the experimentally determined mol-ecular structure in the solid state.

Decrypting the critical point of internal rotation of formaldehyde: A rotational study of the acrolein-formaldehyde complex

The rotational spectrum of an acrolein-formaldehyde complex has been characterized using pulsed jet Fourier transform microwave spectroscopy complemented with quantum chemical calculations. One isomer has been observed in pulsed jets, which is stabilized by a dominant O=C⋯O tetrel bond (n → π* interaction) and a secondary C-H⋯O hydrogen bond. Splittings arising from the internal rotation of formaldehyde around its C2v axis were also observed, from which its V2 barrier was evaluated. It seems that when V2 equals or exceeds 4.61 kJ mol-1, no splitting of the spectral lines of the rotational spectrum was observed. The nature of the non-covalent interactions of the target complex is elucidated through natural bond orbital analysis. These findings contribute to a deeper understanding on the non-covalent interactions within the dimeric complex formed by two aldehydes.

Crystal structure determination and analyses of Hirshfeld surface, crystal voids, inter-molecular inter-action energies and energy frameworks of 1-benzyl-4-(methyl-sulfan-yl)-3a,7a-di-hydro-1H-pyrazolo-[3,4-d]pyrimidine

The pyrazolo-pyrimidine moiety in the title mol-ecule, C13H12N4S, is planar with the methyl-sulfanyl substituent lying essentially in the same plane. The benzyl group is rotated well out of this plane by 73.64 (6)°, giving the mol-ecule an approximate L shape. In the crystal, C-H⋯π(ring) inter-actions and C-H⋯S hydrogen bonds form tubes extending along the a axis. Furthermore, there are π-π inter-actions between parallel phenyl rings with centroid-to-centroid distances of 3.8418 (12) Å. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (47.0%), H⋯N/N⋯H (17.6%) and H⋯C/C⋯H (17.0%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated to be 76.45 Å3 and 6.39%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the cohesion of the crystal structure is dominated by the dispersion energy contributions.

Crystal structure, Hirshfeld surface analysis, calculations of inter-molecular inter-action energies and energy frameworks and the DFT-optimized mol-ecular structure of 1-[(1-butyl-1H-1,2,3-triazol-4-yl)meth-yl]-3-(prop-1-en-2-yl)-1H-benzimidazol-2-one

The benzimidazole entity of the title mol-ecule, C17H21N5O, is almost planar (r.m.s. deviation = 0.0262 Å). In the crystal, bifurcated C-H⋯O hydrogen bonds link individual mol-ecules into layers extending parallel to the ac plane. Two weak C-H⋯π(ring) inter-actions may also be effective in the stabilization of the crystal structure. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (57.9%), H⋯C/C⋯H (18.1%) and H⋯O/O⋯H (14.9%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the most dominant forces in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization of the title compound is dominated via dispersion energy contributions. The mol-ecular structure optimized by density functional theory (DFT) at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state.

Crystal structure and Hirshfeld surface analysis of (Z)-N-{chloro-[(4-ferrocenylphen-yl)imino]-meth-yl}-4-ferrocenylaniline N,N-di-methyl-formamide monosolvate

The title mol-ecule, [Fe2(C5H5)2(C23H17ClN2)]·C3H7NO, is twisted end to end and the central N/C/N unit is disordered. In the crystal, several C-H⋯π(ring) inter-actions lead to the formation of layers, which are connected by further C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (60.2%) and H⋯C/C⋯H (27.0%) inter-actions. Hydrogen bonding, C-H⋯π(ring) inter-actions and van der Waals inter-actions dominate the crystal packing.

Crystal structure, Hirshfeld surface analysis, calculations of crystal voids, inter-action energy and energy frameworks as well as density functional theory (DFT) calculations of 3-[2-(morpholin-4-yl)eth-yl]-5,5-di-phenyl-imidazolidine-2,4-dione

In the title mol-ecule, C21H23N3O3, the imidazolidine ring slightly deviates from planarity and the morpholine ring exhibits the chair conformation. In the crystal, N-H⋯O and C-H⋯O hydrogen bonds form helical chains of mol-ecules extending parallel to the c axis that are connected by C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis reveals that the most important contributions for the crystal packing are from H⋯H (55.2%), H⋯C/C⋯H (22.6%) and H⋯O/O⋯H (20.5%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated to be 236.78 Å3 and 12.71%, respectively. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the nearly equal electrostatic and dispersion energy contributions. The DFT-optimized mol-ecular structure at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state. Moreover, the HOMO-LUMO behaviour was elucidated to determine the energy gap.

[4-(2-Aminoethyl)morpholine-κ2N,N']di-bromidocadmium(II): synthesis, crystal structure and Hirshfeld surface analysis

The title compound, [CdBr2(C6H14N2O)], was synthesized upon complexation of 4-(2-aminoethyl)morpholine and cadmium(II) bromide tetra-hydrate at 303 K. It crystallizes as a centrosymmetric dimer, with one cadmium atom, two bromine atoms and one N,N'-bidentate 4-(2-aminoethyl)morpholine ligand in the asymmetric unit. The metal atom is six-coordinated and has a distorted octa-hedral geometry. In the crystal, O⋯Cd inter-actions link the dimers into a polymeric double chain and inter-molecular C-H⋯O hydrogen bonds form R 2 2(6) ring motifs. Further C-H⋯Br and N-H⋯Br hydrogen bonds link the components into a three-dimensional network. As the N-H⋯Br hydrogen bonds are shorter than the C-H⋯Br inter-actions, they have a larger effect on the packing. A Hirshfeld surface analysis reveals that the largest contributions to the packing are from H⋯H (46.1%) and Br⋯H/H⋯Br (38.9%) inter-actions with smaller contributions from the O⋯H/H⋯O (4.7%), Br⋯Cd/Cd⋯Br (4.4%), O⋯Cd/Cd⋯O (3.5%), Br⋯Br (1.1%), Cd⋯H/H⋯Cd (0.9%), Br⋯O/O⋯Br (0.3%) and O⋯N/N⋯O (0.1%) contacts.

Crystal structure, Hirshfeld surface analysis, crystal voids, inter-action energy calculations and energy frameworks and DFT calculations of ethyl 2-cyano-3-(3-hy-droxy-5-methyl-1H-pyrazol-4-yl)-3-phen-yl-propano-ate

The title compound, C16H17N3O3, is racemic as it crystallizes in a centrosymmetric space group (P ), although the trans disposition of substituents about the central C-C bond is established. The five- and six-membered rings are oriented at a dihedral angle of 75.88 (8)°. In the crystal, N-H⋯N hydrogen bonds form chains of mol-ecules extending along the c-axis direction that are connected by inversion-related pairs of O-H⋯N into ribbons. The ribbons are linked by C-H⋯π(ring) inter-actions, forming layers parallel to the ab plane. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (45.9%), H⋯N/N⋯H (23.3%), H⋯C/C⋯H (16.2%) and H⋯O/O⋯H (12.3%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 100.94 Å3 and 13.20%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the electrostatic energy contributions in the title compound. Moreover, the DFT-optimized structure at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Crystal structure, Hirshfeld surface analysis, crystal voids, inter-action energy calculations and energy frameworks, and DFT calculations of 1-(4-methyl-benz-yl)in-do-line-2,3-dione

The in-do-line portion of the title mol-ecule, C16H13NO2, is planar. In the crystal, a layer structure is generated by C-H⋯O hydrogen bonds and C-H⋯π(ring), π-stacking and C=O⋯π(ring) inter-actions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (43.0%), H⋯C/C⋯H (25.0%) and H⋯O/O⋯H (22.8%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 120.52 Å3 and 9.64%, respectively, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated by the dispersion energy contributions in the title compound. Moreover, the DFT-optimized structure at the B3LYP/6-311G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state.

Crystal structure and Hirshfeld surface analysis of (E)-2-[2-(2-amino-1-cyano-2-oxo-ethyl-idene)hydrazin-1-yl]benzoic acid N,N-di-methylformamide monosolvate

In the title compound, C10H8N4O3·C3H7NO, the asymmetric unit contains two crystallographically independent mol-ecules A and B, each of which has one DMF solvate mol-ecule. Mol-ecules A and B both feature intra-molecular N-H⋯O hydrogen bonds, forming S(6) ring motifs and consolidating the mol-ecular configuration. In the crystal, N-H⋯O and O-H⋯O hydrogen bonds connect mol-ecules A and B, forming R 2 2(8) ring motifs. Weak C-H⋯O inter-actions link the mol-ecules, forming layers parallel to the (12) plane. The DMF solvent mol-ecules are also connected to the main mol-ecules (A and B) by N-H⋯O hydrogen bonds. π-π stacking inter-actions [centroid-to-centroid distance = 3.8702 (17) Å] between the layers also increase the stability of the mol-ecular structure in the third dimension. According to the Hirshfeld surface study, O⋯H/H⋯O inter-actions are the most significant contributors to the crystal packing (27.5% for mol-ecule A and 25.1% for mol-ecule B).

Crystal structure and Hirshfeld surface analysis of dimethyl 4-hy-droxy-5,4'-dimethyl-2'-(toluene-4-sulfonyl-amino)-biphenyl-2,3-di-carboxyl-ate

In the title compound, C25H25NO7S, the mol-ecular conformation is stabilized by intra-molecular O-H⋯O and N-H⋯O hydrogen bonds, which form S(6) and S(8) ring motifs, respectively. The mol-ecules are bent at the S atom with a C-SO2-NH-C torsion angle of -70.86 (11)°. In the crystal, mol-ecules are linked by C-H⋯O and N-H⋯O hydrogen bonds, forming mol-ecular layers parallel to the (100) plane. C-H⋯π inter-actions are observed between these layers.

Crystal structure, Hirshfeld surface analysis, inter-molecular inter-action energies, energy frameworks and DFT calculations of 4-amino-1-(prop-2-yn-1-yl)pyrimidin-2(1H)-one

In the title mol-ecule, C7H7N3O, the pyrimidine ring is essentially planar, with the propynyl group rotated out of this plane by 15.31 (4)°. In the crystal, a tri-periodic network is formed by N-H⋯O, N-H⋯N and C-H⋯O hydrogen-bonding and slipped π-π stacking inter-actions, leading to narrow channels extending parallel to the c axis. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (36.2%), H⋯C/C⋯H (20.9%), H⋯O/O⋯H (17.8%) and H⋯N/N⋯H (12.2%) inter-actions, showing that hydrogen-bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the electrostatic energy contributions. The mol-ecular structure optimized by density functional theory (DFT) calculations at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined structure in the solid state. The HOMO-LUMO behaviour was also elucidated to determine the energy gap.

Crystal structure, Hirshfeld surface and crystal void analysis, inter-molecular inter-action energies, DFT calculations and energy frameworks of 2H-benzo[b][1,4]thia-zin-3(4H)-one 1,1-dioxide

In the title mol-ecule, C8H7NO3S, the nitro-gen atom has a planar environment, and the thia-zine ring exhibits a screw-boat conformation. In the crystal, corrugated layers of mol-ecules parallel to the ab plane are formed by N-H⋯O and C-H⋯O hydrogen bonds together with C-H⋯π(ring) and S=O⋯π(ring) inter-actions. The layers are connected by additional C-H⋯O hydrogen bonds and π-stacking inter-actions. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯O/O⋯H (49.4%), H⋯H (23.0%) and H⋯C/C⋯H (14.1%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated as 75.4 Å3 and 9.3%. Density functional theory (DFT) computations revealed N-H⋯O and C-H⋯O hydrogen-bonding energies of 43.3, 34.7 and 34.4 kJ mol-1, respectively. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via the electrostatic energy contribution. Moreover, the DFT-optimized structure at the B3LYP/ 6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Synthesis, crystal structure and Hirshfeld surface analysis of di-acetato-bis-[4-(2-amino-eth-yl)morpholine]cadmium tetra-hydrate

The title coordination compound, [Cd(C2H3O2)2(C6H14N2O)2]·4H2O, was synthesized by mixing 2 moles of 4-(2-amino-eth-yl)morpholine and 1 mole of cadmium acetate in double-distilled water. The Cd atom is octa-hedrally coord-inated by two N,N'-bidentate ligands [4-(2-amino-eth-yl)morpholine] and two trans-located acetate mol-ecules. The Cd atom is located on a center of inversion, whereas the 4-(2-amino-eth-yl)morpholine and four water mol-ecules are adjacent to the acetate mol-ecules. The chair conformation of the morpholine mol-ecules is confirmed. In the crystal, adjacent metal complexes and uncoord-inated water mol-ecules are linked via N-H⋯O and O-H⋯O hydrogen-bonding inter-actions, generating R 2 2(6), R 6 6(16), R 6 6(20) and S 1 1(6) motifs and forming a three-dimensional network. A Hirshfeld surface analysis indicated the contributions of various contacts: H⋯H (71.8%), O⋯H/H⋯O (27.1%), and C⋯H/H⋯C (1.0%).

Crystal structure, Hirshfeld surface analysis, inter-action energy and energy framework calculations, as well as density functional theory (DFT) com-putation, of methyl 2-oxo-1-(prop-2-yn-yl)-1,2-di-hydro-quinoline-4-carboxyl-ate

In the title mol-ecule, C14H11NO3, the di-hydro-quinoline core deviates slightly from planarity, indicated by the dihedral angle of 1.07 (3)° between the two six-membered rings. In the crystal, layers of mol-ecules almost parallel to the bc plane are formed by C-H⋯O hydro-gen bonds. These are joined by π-π stacking inter-actions. A Hirshfeld surface analysis revealed that the most important contributions to the crystal packing are from H⋯H (36.0%), H⋯C/C⋯H (28.9%) and H⋯O/O⋯H (23.5%) inter-actions. The evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the dispersion energy contribution. Moreover, the mol-ecular structure optimized by density functional theory (DFT) at the B3LYP/6-311G(d,p) level is com-pared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Synthesis, Structural Investigations, DNA/BSA Interactions, Molecular Docking Studies, and Anticancer Activity of a New 1,4-Disubstituted 1,2,3-Triazole Derivative

We report herein a new 1,2,3-triazole derivative, namely, 4-((1-(3,4-dichlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-hydroxybenzaldehyde, which was synthesized by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The structure of the compound was analyzed using Fourier transform infrared spectroscopy (FTIR), 1H NMR, 13C NMR, UV-vis, and elemental analyses. Moreover, X-ray crystallography studies demonstrated that the compound adapted a monoclinic crystal system with the P21/c space group. The dominant interactions formed in the crystal packing were found to be hydrogen bonding and van der Waals interactions according to Hirshfeld surface (HS) analysis. The volume of the crystal voids and the percentage of free spaces in the unit cell were calculated as 152.10 Å3 and 9.80%, respectively. The evaluation of energy frameworks showed that stabilization of the compound was dominated by dispersion energy contributions. Both in vitro and in silico investigations on the DNA/bovine serum albumin (BSA) binding activity of the compound showed that the CT-DNA binding activity of the compound was mediated via intercalation and BSA binding activity was mediated via both polar and hydrophobic interactions. The anticancer activity of the compound was also tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using human cell lines including MDA-MB-231, LNCaP, Caco-2, and HEK-293. The compound exhibited more cytotoxic activity than cisplatin and etoposide on Caco-2 cancer cell lines with an IC50 value of 16.63 ± 0.27 μM after 48 h. Annexin V suggests the induction of cell death by apoptosis. Compound 3 significantly increased the loss of mitochondrial membrane potential (MMP) levels in Caco-2 cells, and the reactive oxygen species (ROS) assay proved that compound 3 could induce apoptosis by ROS generation.

Crystal structure and Hirshfeld surface analysis of (2E)-1-(4-bromo-phen-yl)-3-(2-methyl-phen-yl)prop-2-en-1-one

In the title com-pound, C16H13BrO, the planes of the aromatic rings are inclined at an angle of 23.49 (15)°, and the configuration about the C=C bond is E. In the crystal, the mol-ecules are linked into chains by weak C-H⋯O inter-actions along the b axis. Successive chains form a zigzag structure along the c axis, and these chains are connected to each other by face-to-face π-π stacking inter-actions along the a axis. These layers, parallel to the (001) plane, are linked by van der Waals inter-actions, thus consolidating the crystal structure. Hirshfeld surface analysis showed that the most significant contacts in the structure are H⋯H (43.1%), C⋯H/H⋯C (17.4%), Br⋯H/H⋯Br (14.9%), C⋯C (11.9%) and O⋯H/H⋯O (9.8%).

Synthesis, DFT and molecular docking of novel (Z)-4-bromo-N-(4-butyl-3 (quinolin-3-yl)thiazol-2(3H)-ylidene)benzamide as elastase inhibitor

A new compound, C23H20BrN3OS, containing a quinoline-based iminothiazoline with a thiazoline ring, was synthesized and its crystal and molecular structures were analyzed through single crystal X-ray analysis. The compound belongs to the triclinic system P - 1 space group, with dimensions of a = 9.2304 (6) Å, b = 11.1780 (8) Å, c = 11.3006 (6) Å, α = 107.146 (5)°, β = 93.701 (5)°, γ = 110.435 (6)°, Z = 2 and V = 1025.61 (12) Å3. The crystal structure showed that C-H···N and C-H···O hydrogen bond linkages, forming infinite double chains along the b-axis direction, and enclosing R22(14) and R22(16) ring motifs. The Hirshfeld surface analysis revealed that H…H (44.1%) and H…C/C…H (15.3%) interactions made the most significant contribution. The newly synthesized (Z)-4-bromo-N-(4-butyl-3 (quinolin-3-yl)thiazol-2(3H)-ylidene)benzamide, in comparison to oleanolic acid, exhibited more strong potential against elastase with an inhibition value of 1.21 µM. Additionally, the derivative was evaluated using molecular docking and molecular dynamics simulation studies, which showed that the quinoline based iminothiazoline derivative has the potential to be a novel inhibitor of elastase enzyme. Both theoretical and experimental findings suggested that this compound could have a number of biological activities.

Aqua-{μ-1,4-bis-[(1,4,7,10-tetra-aza-cyclo-dodecan-1-yl)meth-yl]benzene}(nitrato-κO)dicopper(II) tris-(nitrate) trihydrate

In the title dinuclear CuII complex, [Cu2(NO3)(C24H46N8)(H2O)](NO3)3·3H2O, the two CuII mol-ecules both have a square-pyramidal geometry, but the ligands in the axial positions are different: a water mol-ecule and a nitrate ion. All nitrate ions, water mol-ecules, and N-H groups are involved in an inter-molecular hydrogen-bond network.

Crystal structure and Hirshfeld surface analysis of 2,2'-[(3,5-di-tert-butyl-4-hy-droxy-phen-yl)methanedi-yl]bis-(3-hy-droxy-5,5-di-methyl-cyclo-hex-2-en-1-one)

In the title compound, C31H44O5, mol-ecules are connected by O-H⋯O and C-H⋯O hydrogen bonds, forming hydrogen-bonded zigzag chains running along the b axis and parallel to the (001) plane. The mol-ecular packing is stabilized by van der Waals inter-actions between these chains along the a and c axes. The inter-molecular inter-actions in the crystal structure were qu-anti-fied and analysed using Hirshfeld surface analysis.

Crystal structure and Hirshfeld surface analysis of 2,5-di-imino-8a-methyl-4,9-bis-(4-methyl-phen-yl)-7-oxo-6-phenyl-deca-hydro-2H-3,8-methano-pyrano[3,2-c]pyridine-3,4a-dicarbo-nitrile N,N-di-methyl-formamide monosolvate

In the title compound, C32H29N5O2·C3H7NO, the bi-cyclo[3.3.1]nonane ring sys-tem adopts a half-chair/twist-boat conformation, with the phenyl rings in equatorial orientations with respect to the piperidine ring. The two oxane rings of the 2-oxabi-cyclo-[2.2.2]octane ring system exhibit a distorted boat conformation. Inter-molecular C-H⋯O and C-H⋯N hydrogen bonds connect the mol-ecules in the crystal, generating layers extending parallel to (100). These layers are connected by C-H⋯π inter-actions. A Hirshfeld surface analysis was per-formed to qu-antify the contributions of the different inter-molecular inter-actions, indicating that the most important contributions to the crystal packing are from H⋯H (52.5%), N⋯H/H⋯N (19.2%), C⋯H/H⋯C (18.8%) and O⋯H/H⋯O (8.3%) inter-actions.

Crystal structure and Hirshfeld surface analysis of (22 RS,23 SR,25 RS,26 SR)-23,25,5-trimethyl-21-(2,2,2-tri-fluoro-acet-yl)-5-aza-2(2,6)-piperidina-1,3(2,5)-di-furana-cyclo-hexa-phan-24-one

The title compound, C20H21F3N2O4, features a main twelve-membered difuryl ring with which the furan rings make dihedral angles of 76.14 (5) and 33.81 (5)°. The dihedral angle between the furan rings is 42.55 (7)°. The six-membered nitro-gen heterocycle has a twist-boat conformation. In the crystal, pairs of mol-ecules are connected by inter-molecular C-H⋯O inter-actions, generating an R 2 2(14) ring motif. These pairs of mol-ecules form zigzag chains along the a-axis direction by means of C-H⋯F inter-actions. Furthermore, C-H⋯π and C-F⋯π inter-actions link the mol-ecules into chains along the b-axis direction, forming sheets parallel to the (001) plane. These sheets are also connected by van der Waals inter-actions.

Synthesis, crystal structure and Hirshfeld surface analysis of bis-[4-(2-amino-eth-yl)morpholine-κ2 N,N']di-aqua-nickel(II) dichloride

The title coordination compound, [Ni(C6H14N2O)2(H2O)2]Cl2, was synthesized by mixing 4-(2-amino-eth-yl)morpholine and nickel chloride in double-distilled water. The asymmetric unit comprises one half of an NiII cation (located on an inversion centre), one 4-(2-amino-eth-yl)morpholine ligand, one coordinated water mol-ecule and one chloride ion outside the metal coordination sphere. The nickel ion is in a octa-hedral environment of the N4O2 type, coordinating four N atoms from two 4-(2-amino-eth-yl)morpholine ligands and two trans-located O atoms from two water mol-ecules. The morpholine ligand was found disordered over two positions with a site occupancy ratio of 0.708 (8):0.292 (8). The crystal structure is consolidated by N-H⋯Cl, N-H⋯O, C-H⋯Cl and C-H⋯O hydrogen bonds. Hirshfeld surface analysis confirms that van der Waals inter-actions are prevalent in the crystal packing of the synthesized complex.

Phosphorus-nitrogen compounds. Part 58. Syntheses, structural characterizations and biological activities of 4-fluorobenzyl-spiro(N/O)cyclotriphosphazene derivatives

The starting compound, tetrachloro-4-fluorobenzyl-spiro(N/O)cyclotriphosphazene (2), was synthesized from the substitution reaction of hexachlorocyclotriphosphazatriene (N₃P₃Cl₆; trimer; HCCP) with sodium 3-(4-fluorobenzylamino)-1-propanoxide (1). Reactions of spiro (2) with excess 1-(2-aminoethyl)-piperidine, 4-(2-aminoethyl)-morpholine, 1-(2-hydroxyethyl)piperidine and 4-(2-aminoethyl)morpholine yielded the fully substituted cyclotriphosphazene derivatives (2a-2d), respectively. Elemental analysis, mass spectrometry (ESI-MS), FTIR, ¹H-, ¹³C- and ³¹P-NMR data confirmed the structure of the new cyclotriphosphazenes (2a-2d); and the crystal structure of 2 was also identified by X-ray crystallography. The quantum mechanical DFT calculations of 2 were performed to estimate the geometry optimization, total energy, orientation of frontier molecular orbitals (HOMOs and LUMOs), and chemical parameters. In addition, antibacterial and antifungal activities of the fully substituted 4-fluorobenzyl-spiro(N/O)cyclotriphosphazenes (2a-2d) were investigated against G(+) and G(-) bacteria and fungi. Using agarose gel electrophoresis, the DNA cleavage activities of these phosphazenes on double-stranded plasmid DNA were evaluated. To evaluate the abilities of compounds 2a-2d to inhibit cell proliferation in different concentrations, the antiproliferative and antimigrative activities against prostate adenocarcinoma (PC3), breast cancer (MCF7) and colon cancer (HT29) cell lines were studied in vitro; and the compound 2c was determined to be the most efficient against the three cancer cells.Communicated by Ramaswamy H. Sarma.

Acetophenone-Based 3,4-Dihydropyrimidine-2(1H)-Thione as Potential Inhibitor of Tyrosinase and Ribonucleotide Reductase: Facile Synthesis, Crystal Structure, In-Vitro and In-Silico Investigations

The acetophenone-based 3,4-dihydropyrimidine-2(1H)-thione was synthesized by the reaction of 4-methylpent-3-en-2-one (1), 4-acetyl aniline (2) and potassium thiocyanate. The spectroscopic analysis including: FTIR, 1H-NMR, and single crystal analysis proved the structure of synthesized compound (4), with the six-membered nonplanar ring in envelope conformation. In crystal structure, the intermolecular N-H ⋯ S and C-H ⋯ O hydrogen bonds link the molecule in a two-dimensional manner which is parallel to (010) the plane enclosing R22 (8) and R22 (10) ring motifs. After that, the Hirshfeld surfaces and their related two-dimensional fingerprint plots were used for thorough investigation of intermolecular interactions. According to Hirshfeld surface analysis, the most substantial contributions to the crystal packing are from H ⋯ H (59.5%), H ⋯ S/S ⋯ H (16.1%), and H ⋯ C/C ⋯ H (13.1%) interactions. The electronic properties and stability of the compound were investigated through density functional theory (DFT) studies using B3LYP functional and 6-31G* as a basis set. The compound 4 displayed the high chemical reactivity with chemical softness of 2.48. In comparison to the already reported known tyrosinase inhibitor, the newly synthesized derivatives exhibited almost seven-fold better inhibition of tyrosinase (IC50 = 1.97 μM), which was further supported by molecular docking studies. The compound 4 inside the active pocket of ribonucleotide reductase (RNR) exhibited a binding energy of -19.68 kJ/mol, and with mammalian deoxy ribonucleic acid (DNA) it acts as an effective DNA groove binder with a binding energy of -21.32 kJ/mol. The results suggested further exploration of this compound at molecular level to synthesize more potential leads for the treatment of cancer.

Crystal structure determination, Hirshfeld surface, crystal void, inter-molecular inter-action energy analyses, as well as DFT and energy framework calculations of 2-(4-oxo-4,5-di-hydro-1H-pyra-zolo[3,4-d]pyrimidin-1-yl)acetic acid

In the title mol-ecule, C7H6N4O3, the bicyclic ring system is planar with the carb-oxy-methyl group inclined by 81.05 (5)° to this plane. In the crystal, corrugated layers parallel to (010) are generated by N-H⋯O, O-H⋯N and C-H⋯O hydrogen-bonding inter-actions. The layers are associated through C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯O/O⋯H (34.8%), H⋯N/N⋯H (19.3%) and H⋯H (18.1%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated to be 176.30 Å3 and 10.94%, showing that there is no large cavity in the crystal packing. Computational methods revealed O-H⋯N, N-H⋯O and C-H⋯O hydrogen-bonding energies of 76.3, 55.2, 32.8 and 19.1 kJ mol-1, respectively. Evaluations of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via dispersion energy contributions. Moreover, the optimized mol-ecular structure, using density functional theory (DFT) at the B3LYP/6-311G(d,p) level, was compared with the experimentally determined one. The HOMO-LUMO energy gap was determined and the mol-ecular electrostatic potential (MEP) surface was calculated at the B3LYP/6-31G level to predict sites for electrophilic and nucleophilic attacks.

Crystal structure, Hirshfeld surface analysis and DFT calculations of (E)-3-[1-(2-hy-droxy-phenyl-anilino)ethyl-idene]-6-methyl-pyran-2,4-dione

The asymmetric unit of the title compound, C14H13NO4, contains three independent mol-ecules, which differ slightly in conformation. Each contains an intra-molecular N-H⋯O hydrogen bond. In the crystal, O-H⋯O hydrogen bonds form chains of mol-ecules, which are linked into corrugated sheets parallel to (03) plane by C-H⋯O hydrogen bonds together with π inter-actions between the carbonyl groups and the 2-hy-droxy-phenyl rings. The layers are linked by further C-H⋯O hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (49.0%), H⋯O/O⋯H (28.3%) and H⋯C/C⋯H (10.9%) inter-actions. van der Waals inter-actions are the dominant inter-actions in the crystal packing. Moreover, density functional theory (DFT) optimized structures at the B3LYP/ 6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behavior was elucidated to determine the energy gap of 4.53 eV.

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.

Crystal structure, Hirshfeld surface analysis, inter-action energy and DFT calculations and energy frameworks of methyl 6-chloro-1-methyl-2-oxo-1,2-di-hydro-quinoline-4-carboxyl-ate

In the title compound, C12H10ClNO3, the di-hydro-quinoline moiety is not planar with a dihedral angle between the two ring planes of 1.61 (6)°. An intra-molecular C-H⋯O hydrogen bond helps to establish the rotational orientation of the carboxyl group. In the crystal, sheets of mol-ecules parallel to (10) are generated by C-H⋯O and C-H⋯Cl hydrogen bonds, and are stacked through slipped π-stacking inter-actions between inversion-related di-hydro-quinoline units. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (34.2%), H⋯O/O⋯H (19.9%), H⋯Cl/Cl⋯H (12.8%), H⋯C/C⋯H (10.3%) and C⋯C (9.7%) inter-actions. Computational chemistry indicates that in the crystal, the C-H⋯Cl hydrogen-bond energy is -37.4 kJ mol-1, while the C-H⋯O hydrogen-bond energies are -45.4 and -29.2 kJ mol-1. An evaluation of the electrostatic, dispersion and total energy frameworks revealed that the stabilization is dominated via the dispersion energy contribution. Density functional theory (DFT) optimized structures at the B3LYP/6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state, and the HOMO-LUMO behaviour was elucidated to determine the energy gap.

Crystal structure and Hirshfeld surface analysis of (E)-1-[2,2-di-bromo-1-(2-nitro-phen-yl)ethen-yl]-2-(4-fluoro-phen-yl)diazene

In the title compound, C14H8Br2FN3O2, the nitro-substituted benzene ring and the 4-fluoro-phenyl ring form a dihedral angle of 65.73 (7)°. In the crystal, mol-ecules are linked into chains by C-H⋯O hydrogen bonds running parallel to the c-axis direction. The crystal packing is consolidated by C-F⋯π inter-actions and π-π stacking inter-actions, and short Br⋯O [2.9828 (13) Å] contacts are observed. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (17.4%), O⋯H/H⋯O (16.3%), Br⋯H/H⋯Br (15.5%), Br⋯C/C⋯Br (10.1%) and F⋯H/H⋯F (8.1%) contacts.