checkCIF validation ALERTS: what they mean and how to respond

Identification of potent indolizine derivatives against Mycobacterial tuberculosis: In vitro anti-TB properties, in silico target validation, molecular docking and dynamics studies

In the current study, two sets of compounds: (E)-1-(2-(4-substitutedphenyl)-2-oxoethyl)-4-((hydroxyimino)methyl)pyridinium derivatives (3a-3e); and (E)-3-(substitutedbenzoyl)-7-((hydroxyimino)methyl)-2-substitutedindolizine-1-carboxylate derivatives (5a-5j), were synthesized and biologically evaluated against two strains of Mycobacterial tuberculosis (ATCC 25177) and multi-drug resistant (MDR) strains. Further, they were also tested in vitro against the mycobacterial InhA enzyme. The in vitro results showed excellent inhibitory activities against both MTB strains and compounds 5a-5j were found to be more potent, and their MIC values ranged from 5 to 16 μg/mL and 16-64 μg/mL against the M. tuberculosis (ATCC 25177) and MDR-TB strains, respectively. Compound 5h with phenyl and 4-fluorobenzoyl groups attached to the 2- and 3-position of the indolizine core was found to be the most active against both strains with MIC values of 5 μg/mL and 16 μg/mL, respectively. On the other hand, the two sets of compounds showed weak to moderate inhibition of InhA enzyme activity that ranged from 5 to 17 % and 10-52 %, respectively, with compound 5f containing 4-fluoro benzoyl group attached to the 3-position of the indolizine core being the most active (52 % inhibition of InhA). Unfortunately, there was no clear correlation between the InhA inhibitory activity and MIC values of the tested compounds, indicating the probability that they might have different modes of action other than InhA inhibition. Therefore, a computational investigation was conducted by employing molecular docking to identify their putative drug target(s) and, consequently, understand their mechanism of action. A panel of 20 essential mycobacterial enzymes was investigated, of which β-ketoacyl acyl carrier protein synthase I (KasA) and pyridoxal-5'-phosphate (PLP)-dependent aminotransferase (BioA) enzymes were revealed as putative targets for compounds 3a-3e and 5a-5j, respectively. Moreover, in silico ADMET predictions showed adequate properties for these compounds, making them promising leads worthy of further optimization.

Na[GeF5]·2HF: the first quarternary phase in the H-Na-Ge-F system

The structure of cis- or trans-bridged [GeF5]- anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem. 23, 3160-3166] showing the first crystal structures of μ-F-bridged pentafluorogermanates. Herein, we report the second crystal structure of trans-pentafluorogermanate anions present in the crystal structure of sodium trans-pentafluorogermanate(IV) bis(hydrogen fluoride), Na[GeF5]·2HF. The crystal structure [orthorhombic Pca21, a = 12.3786 (3), b = 7.2189 (2), c = 11.4969 (3) Å and Z = 8] is built up from infinite chains of trans-linked [GeF6]2- octahedra, extending along the b axis and spanning a network of pentagonal bipyramidal distorted Na-centred polyhedra. These [NaF7] polyhedra are linked in a trans-edge fashion via hydrogen fluoride molecules, in analogy to already known sodium hydrogen fluorides and potassium hydrogen fluorides.

Crystal structure and cryomagnetic study of a mononuclear erbium(III) oxamate inclusion complex

The synthesis, crystal structure and magnetic properties of an oxamate-containing erbium(III) complex, namely, tetrabutylammonium aqua[N-(2,4,6-trimethylphenyl)oxamato]erbium(III)-dimethyl sulfoxide-water (1/3/1.5), (C16H36N)[Er(C11H12NO3)4(H2O)]·3C2H6OS·1.5H2O or n-Bu4N[Er(Htmpa)4(H2O)]·3DMSO·1.5H2O (1), are reported. The crystal structure of 1 reveals the occurrence of an erbium(III) ion, which is surrounded by four N-phenyl-substituted oxamate ligands and one water molecule in a nine-coordinated environment, together with one tetrabutylammonium cation acting as a counter-ion, and one water and three dimethyl sulfoxide (DMSO) molecules of crystallization. Variable-temperature static (dc) and dynamic (ac) magnetic measurements were carried out for this mononuclear complex, revealing that it behaves as a field-induced single-ion magnet (SIM) below 5.0 K.

3-[(Benzo-1,3-dioxol-5-yl)amino]-4-methoxycyclobut-3-ene-1,2-dione: polymorphism and twinning of a precursor to an antimycobacterial squaramide

The title compound, 3-[(benzo-1,3-dioxol-5-yl)amino]-4-methoxycyclobut-3-ene-1,2-dione, C12H9NO5 (3), is a precursor to an antimycobacterial squaramide. Block-shaped crystals of a monoclinic form (3-I, space group P21/c, Z = 8, Z' = 2) and needle-shaped crystals of a triclinic form (3-II, space group P-1, Z = 4, Z' = 2) were found to crystallize concomitantly. In both crystal forms, R22(10) dimers assemble through N-H...O=C hydrogen bonds. These dimers are formed from crystallographically unique molecules in 3-I, but exhibit crystallographic Ci symmetry in 3-II. Twinning by pseudomerohedry was encountered in the crystals of 3-II. The conformations of 3 in the solid forms 3-I and 3-II are different from one another but are similar for the unique molecules in each polymorph. Density functional theory (DFT) calculations on the free molecule of 3 indicate that a nearly planar conformation is preferred.

Using cocrystals as a tool to study non-crystallizing molecules: crystal structure, Hirshfeld surface analysis and computational study of the 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine and acetic acid

Using a 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π-π interactions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and computational studies, we reveal the molecular arrangement within this cocrystal, demonstrating the presence of hydrogen bonding between the acetic acid molecule and the pyridyl group, along with π-π interactions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π-π interactions without necessitating full halogenation of the aromatic ring.

Supramolecular interactions in cocrystals of benzoic acid derivatives with selective COX-2 inhibitor etoricoxib

The structures of three 1:1 cocrystal forms of etoricoxib {ETR; systematic name: 5-chloro-2-(6-methylpyridin-3-yl)-3-[4-(methylsulfonyl)phenyl]pyridine, C18H15ClN2O2S} have been synthesized and characterized by single-crystal X-ray diffraction; these are etoricoxib-benzoic acid (1/1), C18H15ClN2O2S·C7H6O2 (ETR-Bz), etoricoxib-4-fluorobenzoic acid (1/1), C18H15ClN2O2S·C7H5FO2 (ETR-PFB), and etoricoxib-4-nitrobenzoic acid (1/1), C18H15ClN2O2S·C7H5NO4 (ETR-PNB). Powder X-ray diffraction and thermal differential scanning calorimetry-thermogravimetry (DSC-TG) techniques were also used to characterize these multicomponent systems. Due to the influence of the corresponding acids, ETR shows different conformations. Furthermore, the energetic contributions of the supramolecular motifs have been established by energy framework studies of the stabilizing interaction forces and are consistent with the thermal stability of the cocrystals.

Synthesis, spectroscopic and crystallographic characterization of various cymantrenyl thioethers [Mn{C5HxBry(SMe)z}(PPh3)(CO)2]

Starting from [Mn(C5H4Br)(PPh3)(CO)2] (1a), the cymantrenyl thioethers [Mn(C5H4SMe)(PPh3)(CO)2] (1b) and [Mn{C5H4-nBr(SMe)n}(PPh3)(CO)2] (n = 1 for compound 2, n = 2 for 3 and n = 3 for 4) were obtained, using either n-butyllithium (n-BuLi), lithium diisopropylamide (LDA) or lithium tetramethylpiperidide (LiTMP) as base, followed by electrophilic quenching with MeSSMe. Stepwise consecutive reaction of [Mn(C5Br5)(PPh3)(CO)2] with n-BuLi and MeSSMe led finally to [Mn{C5(SMe)5}(PPh3)(CO)2] (11), only the fifth complex to be reported containing a perthiolated cyclopentadienyl ring. The molecular and crystal structures of 1b, 3, 4 and 11 were determined and were studied for the occurrence of S...S and S...Br interactions. It turned out that although some interactions of this type occurred, they were of minor importance for the arrangement of the molecules in the crystal.

A cobalt(II) coordination polymer-derived catalyst engineered via temperature-induced semi-reversible single-crystal-to-single-crystal (SCSC) dehydration for efficient liquid-phase epoxidation of olefins

Single-crystal-to-single-crystal (SCSC) transformations provide more avenues for phase transitions, which have piqued great interest in crystal engineering. In this work, a 3D Co(II)-based coordination polymer (CP), {Co2(OH2)8(btec)}·4H2O (1), (where (btec)4- = 1,2,4,5-benzenetetracarboxylate) undergoes SCSC transition upon heating at 180 °C to afford an anhydrous phase [Co2(btec)] (1'). Room-temperature water-vapour induced semi-reversible SCSC transformation of 1' involves condensation of two water molecules coordinating to the metal cluster, yielding a new framework [Co2(OH2)2(btec)] (2). These SCSC transitions were accomplished through a sequential bond breaking and new bond formation process which was accompanied by colour changes from orange (1) → violet (1') → pink (2). All materials were structurally elucidated by single-crystal X-ray diffraction (SCXRD) and further established by various analytical techniques. According to SCXRD data, all the frameworks possess octahedral geometries around the cobalt(II) sphere. SCXRD studies further revealed that 1 is a polymeric architecture with a binodal 4-c sql topology while 1' and 2 possess (3,6)-c kgd and (4,6)-c scu 3D nets, respectively. By virtue of multitopicity exhibited by the tetracarboxylate, the coordination number of the linker around the Co(II) sphere increased from four (in 1) to eight (in 1') and then decreased to six (in 2). Most interestingly, permanent porosity could be observed for the dihydrate 2, originated from potential void space as substantiated by dinitrogen (N2) sorption isotherm. These porous frameworks were active catalysts for the aerobic epoxidation of the model substrate cyclohexene using molecular oxygen (O2) as the final oxidant in the presence of the sacrificial i-butyraldehyde (IBA) reductant. For using the dihydrous phase 2, cyclohexene and various other olefins were catalytically oxidised to their corresponding epoxides with up to 38.5% conversion and 99.0% selectivity. The catalyst 2 can be expediently recycled in four runs without significant loss of activity. This research demonstrates that a little innovation in the active-site-engineered organic-inorganic hybrid materials can significantly enhance the catalytic performance and selectivity of coordination polymer-derived heterogeneous catalysts.

Crystal structure elucidation of a geminal and vicinal bis(trifluoromethanesulfonate) ester

Geminal and vicinal bis(trifluoromethanesulfonate) esters are highly reactive alkylene synthons used as potent electrophiles in the macrocyclization of imidazoles and the transformation of bypyridines to diquat derivatives via nucleophilic substitution reactions. Herein we report the crystal structures of methylene (C3H2F6O6S2) and ethylene bis(trifluoromethanesulfonate) (C4H4F6O6S2), the first examples of a geminal and vicinal bis(trifluoromethanesulfonate) ester characterized by single-crystal X-ray diffraction (SC-XRD). With melting points slightly below ambient temperature, both reported bis(trifluoromethanesulfonate)s are air- and moisture-sensitive oils and were crystallized at 277 K to afford two-component non-merohedrally twinned crystals. The dominant interactions present in both compounds are non-classical C-H...O hydrogen bonds and intermolecular C-F...F-C interactions between trifluoromethyl groups. Molecular electrostatic potential (MEP) calculations by DFT-D3 helped to quantify the polarity between O...H and F...F contacts to rationalize the self-sorting of both bis(trifluoromethanesulfonate) esters in polar (non-fluorous) and non-polar (fluorous) domains within the crystal structure.

Synthesis and structural characterizations of three carbonyl(α-diimine)hydrido(triphenylphosphine)ruthenium(II) complexes with derivatives of 1,10-phenanthroline

Three new ruthenium(II) polypyridyl complexes containing α-diimine ligands, namely, carbonylhydrido(1,10-phenanthroline-κ2N,N)bis(triphenylphosphine-κP)ruthenium(II) hexafluorophosphate, [RuH(C12H8N2)(C18H15P)2(CO)]PF6, carbonylhydrido(2,9-dimethyl-1,10-phenanthroline-κ2N,N)bis(triphenylphosphine-κP)ruthenium(II) hexafluorophosphate, and carbonylhydrido(4,7-dimethyl-1,10-phenanthroline-κ2N,N)bis(triphenylphosphine-κP)ruthenium(II) hexafluorophosphate, both [RuH(C14H12N2)(C18H15P)2(CO)]PF6, were synthesized and characterized by spectroscopic and X-ray diffraction methods. In these complexes, the ruthenium(II) ion adopts a distorted octahedral geometry. There are no intermolecular hydrogen bonds in the crystal structures of the analysed complexes and Hirshfeld surface analysis showed that the H...H contacts constitute a high percentage, close to 50%, of the intermolecular interactions.

The crystal structure of the ammonium salt of 2-aminomalonic acid

The salt ammonium 2-aminomalonate (systematic name: ammonium 2-azaniumylpropanedioate), NH4+·C3H4NO4-, was synthesized in diethyl ether from the starting materials malonic acid, ammonia and bromine. The salt was recrystallized from water as colourless blocks. In the solid state, intramolecular medium-strong N-H...O, weak C-H...O and weak C-H...N hydrogen bonds build a three-dimensional network.

Divergent synthesis of complex withanolides enabled by a scalable route and late-stage functionalization

Withanolides are a group of naturally occurring C28 steroids based on an ergostane skeleton. They have a high degree of polyoxygenation, and the abundance of O-functional groups has enabled various natural alterations to both the carbocyclic skeleton and the side chain. Consequently, these molecules have intricate structural features that lead to their highly varied display of biological activities including anticancer, anti-inflammatory, and immunomodulating properties. Despite being intriguing leads for further discovery research, synthetic access to the withanolides remains highly challenging-compounds for current biological research are mainly isolated from plants, often inefficiently. Here, we report the divergent synthesis of 11 withanolides in 12 to 20 steps, enabled by a gram-scale route and a series of late-stage functionalizations, most notably a bioinspired photooxygenation-allylic hydroperoxide rearrangement sequence. This approach enables further biological research disconnected from a reliance on minute quantities of the parent natural products or their simple derivatives.

Narrow-Bandgap Tellurium-Based Chiral Hybrid Perovskite Single Crystals with Rashba-Dresselhaus Effect and Piezoelectricity

Chiral hybrid perovskites have aroused great interest due to their unique versatile properties. However, designing chiral perovskites with narrow bandgaps is challenging, with their electronic properties such as the Rashba-Dresselhaus effect and piezoelectricity remaining unclear. Herein, single crystals of zero-dimensional (0D) tellurium-based chiral hybrid perovskite, (R-/S-α-PEA)2TeI6 and (R-/S-α-PEA)2TeBr6 (PEA = phenylethylammonium), with sizes of over 5 mm are grown by seed-crystal-assisted solution-temperature-lowering. The optical bandgaps are about 1.60 and 2.18 eV for the iodide and bromide analogues, respectively, which are the lowest among various chiral lead-free hybrid perovskites with the same halide ions in the X-site to the best of our knowledge. First-principles calculations reveal that (R-/S-α-PEA)2TeBr6 shows a larger Rashba-Dresselhaus spin-splitting than (R-/S-α-PEA)2TeI6, probably thanks to the greater distortion of [TeBr6] octahedra. Moreover, the piezoelectric coefficients d33 of (R-/S-α-PEA)2TeI6 and (R-/S-α-PEA)2TeBr6 are about 2.6 and 1.8 pC N-1, respectively. This work deepens the understanding of physical properties of 0D tellurium-based chiral perovskites with potential multifunctionality, including spintronic and piezoelectric performances.

Synthesis and crystal structure of bis-(2-aminobenzimidazolium) catena-[metavanadate(V)]

The structure of polymeric catena-poly[2-amino-benzimidazolium [[dioxidovanadium(V)]-μ-oxido]], {(C7H8N3)2[V2O6]} n , has monoclinic symmetry. The title compound is of inter-est with respect to anti-cancer activity. In the crystal structure, infinite linear zigzag vanadate (V2O6)2- chains, constructed from corner-sharing VO4 tetra-hedra and that run parallel to the a axis, are present. Two different protonated 2-amino-benzimidazole mol-ecules are located between the (V2O6)2- chains and form classical N-H⋯O hydrogen bonds with the vanadate oxygen atoms, which contribute to the cohesion of the structure.

Crystal structure and Hirshfeld surface analysis of 6,6'-dimethyl-2,2'-bi-pyridine-1,1'-diium tetra-chlorido-cobaltate(II)

In the title mol-ecular salt, (C12H14N2)[CoCl4], the dihedral angle between the pyridine rings of the cation is 52.46 (9)° and the N-C-C-N torsion angle is -128.78 (14)°, indicating that the ring nitro-gen atoms are in anti-clinal conformation. The Cl-Co-Cl bond angles in the anion span the range 105.46 (3)-117.91 (2)°. In the extended structure, the cations and anions are linked by cation-to-anion N-H⋯Cl and C-H⋯Cl inter-actions, facilitating the formation of R 4 4(18) and R 4 4(20) ring motifs. Furthermore, the crystal structure features weak anion-to-cation Cl⋯π inter-actions [Cl⋯π = 3.4891 (12) and 3.5465 (12) Å]. Hirshfeld two-dimensional fingerprint plots revealed that the most significant inter-actions are Cl⋯H/H⋯Cl (45.5%), H⋯H (29.0%), Cl⋯C/C⋯Cl (7.8%), Cl⋯N/N⋯Cl (3.5%), Cl⋯Cl (1.4) and Co⋯H (1%) contacts.

Designing Organic π-Conjugated Molecules for Crystalline Solid Solutions: Adamantane-Substituted Naphthalenes

We showcase herein organic crystalline solid solutions (CSSs) based on the simplest polycyclic aromatic hydrocarbon (PAH) scaffold, naphthalene, stabilized by dispersion forces induced by adamantane substitution. High thermal stability of the host and guest molecules synthesized by cross-coupling of dibromonaphthalene derivatives and 4-(1-adamantyl)phenyl boronic ester enabled formation of crystals by sublimation. We could generate binary monocrystalline solid solution systems proven by X-ray crystallography, the first system of designed CSSs stabilized exclusively via dispersion forces with structural evidence. These observations are additionally supported by lattice energy calculations and spectroscopic examinations. For the generation of CSSs, it is of utmost importance that the host and guest molecules have similar lattice energies and spatial compatibility. We anticipate that the thermostable organic CSS design demonstrated herein would be beneficial for functional materials and further investigation towards materials with unique properties.

Synthesis, structure and Hirshfeld surface analysis of 2-oxo-2H-chromen-4-yl penta-noate

In the title compound, C14H14O4, the dihedral angle between the coumarin ring system (r.m.s deviation = 0.016 Å) and the penta-noate ring is 36.26 (8)°. A short intra-molecular C-H⋯O contact of 2.40 Å is observed. Hirshfeld surface analysis reveals that 46.1% of the inter-molecular inter-actions are from H⋯H contacts, 28.6% are from H⋯O/O⋯H contacts and 14.7% are from H⋯C/C⋯H.

Crystal structure of tricarbon-yl[η4-6-exo-(tri-phenyl-phosphino)cyclo-hepta-2,4-dien-1-one]iron(0) tetra-fluoro-borate

The mol-ecular structure of tricarbon-yl[η4-6-exo-(tri-phenyl-phosphino)cyclo-hepta-2,4-dien-1-one]iron(0) tetra-fluoro-borate di-chloro-methane hemisolvate, [Fe(C28H22O4)(CO)3]BF4·0.5CH2Cl2, as determined by single-crystal X-ray diffraction is reported. The two independent tricarbon-yl[η4-6-exo-(tri-phenyl-phosphino)cyclo-hepta-2,4-dien-1-one] iron(0) cations and their corresponding anions form dimers, which constitute the asymmetric unit of the structure parallel to the (100) plane. Solid-state stability within that asymmetric unit as well as between neighboring dimeric units is afforded by C-H⋯O and C-H⋯F hydrogen bonds and C-H⋯π and Y-X⋯π (Y = B, C; X = F, O) inter-actions, which yield diperiodic sheets and a three-dimensional extended network.

Applying 3D ED/MicroED workflows toward the next frontiers

We report on the latest advancements in Microcrystal Electron Diffraction (3D ED/MicroED), as discussed during a symposium at the National Center for CryoEM Access and Training housed at the New York Structural Biology Center. This snapshot describes cutting-edge developments in various facets of the field and identifies potential avenues for continued progress. Key sections discuss instrumentation access, research applications for small molecules and biomacromolecules, data collection hardware and software, data reduction software, and finally reporting and validation. 3D ED/MicroED is still early in its wide adoption by the structural science community with ample opportunities for expansion, growth, and innovation.

Crystal structure of tris-{N,N-diethyl-N'-[(4-nitro-phen-yl)(oxo)meth-yl]carbamimido-thio-ato}cobalt(III)

The synthesis, crystal structure, and a Hirshfeld surface analysis of tris-{N,N-diethyl-N'-[(4-nitro-phen-yl)(oxo)meth-yl]carbamimido-thio-ato}cobalt(III) conducted at 180 K are presented. The complex consists of three N,N-diethyl-N'-[(4-nitro-benzene)(oxo)meth-yl]carbamimido-thio-ato ligands, threefold sym-metric-ally bonded about the CoIII ion, in approximately octa-hedral coordination, which generates a triple of individually near planar metallacyclic (Co-S-C-N-C-O) rings. The overall geometry of the complex is determined by the mutual orientation of each metallacycle about the crystallographically imposed threefold axis [dihedral angles = 81.70 (2)°] and by the dihedral angles between the various planar groups within each asymmetric unit [metallacycle to benzene ring = 13.83 (7)°; benzene ring to nitro group = 17.494 (8)°]. The complexes stack in anti-parallel columns about the axis of the space group (P), generating solvent-accessible channels along [001]. These channels contain ill-defined, multiply disordered, partial-occupancy solvent. Atom-atom contacts in the crystal packing predominantly (∼96%) involve hydrogen, the most abundant types being H⋯H (36.6%), H⋯O (31.0%), H⋯C (19.2%), H⋯N (4.8%), and H⋯S (4.4%).

Crystal structure and Hirshfeld surface analysis of 1-[6-bromo-2-(4-fluoro-phen-yl)-1,2,3,4-tetra-hydroquinolin-4-yl]pyrrolidin-2-one

In the title compound, C19H18BrFN2O, the pyrrolidine ring adopts an envelope conformation. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O, C-H⋯O, C-H⋯F and C-H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, C-H⋯π inter-actions connect mol-ecules into ribbons along the b-axis direction, consolidating the mol-ecular packing. The inter-molecular inter-actions in the crystal structure were qu-anti-fied and analysed using Hirshfeld surface analysis.

Synthesis, crystal structure and photophysical properties of a dinuclear MnII complex with 6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline

A new quinoline derivative, namely, 6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline, C24H23N3 (QP), and its MnII complex aqua-1κO-di-μ-chlorido-1:2κ4 Cl:Cl-di-chlorido-1κCl,2κCl-bis-[6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline]-1κ2 N 1,N 2;2κ2 N 1,N 2-dimanganese(II), [Mn2Cl4(C24H23N3)2(H2O)] (MnQP), were synthesized. Their compositions have been determined with ESI-MS, IR, and 1H NMR spectroscopy. The crystal-structure determination of MnQP revealed a dinuclear complex with a central four-membered Mn2Cl2 ring. Both MnII atoms bind to an additional Cl atom and to two N atoms of the QP ligand. One MnII atom expands its coordination sphere with an extra water mol-ecule, resulting in a distorted octa-hedral shape. The second MnII atom shows a distorted trigonal-bipyramidal shape. The UV-vis absorption and emission spectra of the examined compounds were studied. Furthermore, when investigating the aggregation-induced emission (AIE) properties, it was found that the fluorescent color changes from blue to green and eventually becomes yellow as the fraction of water in the THF/water mixture increases from 0% to 99%. In particular, these color and intensity changes are most pronounced at a water fraction of 60%. The crystal structure contains disordered solvent mol-ecules, which could not be modeled. The SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18] was used to obtain information on the type and qu-antity of solvent mol-ecules, which resulted in 44 electrons in a void volume of 274 Å3, corresponding to approximately 1.7 mol-ecules of ethanol in the unit cell. These ethanol mol-ecules are not considered in the given chemical formula and other crystal data.

Structural insights and cytotoxicity evaluation of benz[e]indole pyrazolyl-substituted amides

Five new compounds of benz[e]indole pyrazolyl-substituted amides (2a-e) were synthesised in low to good yields via the direct amide-coupling reaction between a pyrazolyl derivative containing a carboxylic acid and several amine substrates. The molecular structures were determined by various spectroscopic methods, such as NMR (1H, 13C and 19F), FT-IR and high-resolution mass spectrometry (HRMS). X-ray crystallographic analysis on the 4-fluorobenzyl derivative (2d) reveals the amide-O atom to reside to the opposite side of the molecule to the pyrazolyl-N and pyrrolyl-N atoms; in the molecular packing, helical chains feature amide-N‒H⋯N(pyrrolyl) hydrogen bonds. Density-functional theory (DFT) at the geometry-optimisation B3LYP/6-31G(d) level on the full series shows general agreement with the experimental structures. While the LUMO in each case is spread over the benz[e]indole pyrazolyl moiety, the HOMO spreads over the halogenated benzo-substituted amide moieties or is localised near the benz[e]indole pyrazolyl moieties. The MTT assay showed that 2e, exhibited the highest toxicity against a human colorectal carcinoma (HCT 116 cell line) without appreciable toxicity towards the normal human colon fibroblast (CCD-18Co cell line). Based on molecular docking calculations, the probable cytotoxic mechanism of 2e is through the DNA minor groove binding.

Synthesis, characterization and structural analysis of complexes from 2,2':6',2''-terpyridine derivatives with transition metals

The synthesis and structural characterization of three families of coordination complexes synthesized from 4'-phenyl-2,2':6',2''-terpyridine (8, Ph-TPY), 4'-(4-chlorophenyl)-2,2':6',2''-terpyridine (9, ClPh-TPY) and 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (10, MeOPh-TPY) ligands with the divalent metals Co2+, Fe2+, Mn2+ and Ni2+ are reported. The compounds were synthesized from a 1:2 mixture of the metal and ligand, resulting in a series of complexes with the general formula [M(R-TPY)2](ClO4)2 (where M = Co2+, Fe2+, Mn2+ and Ni2+, and R-TPY = Ph-TPY, ClPh-TPY and MeOPh-TPY). The general formula and structural and supramolecular features were determinated by single-crystal X-ray diffraction for bis(4'-phenyl-2,2':6',2''-terpyridine)nickel(II) bis(perchlorate), [Ni(C21H15N3)2](ClO4)2 or [Ni(Ph-TPY)2](ClO4)2, bis[4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine]manganese(II) bis(perchlorate), [Mn(C22H17N3O)2](ClO4)2 or [Mn(MeOPh-TPY)2](ClO4)2, and bis(4'-phenyl-2,2':6',2''-terpyridine)manganese(II) bis(perchlorate), [Mn(C21H15N3)2](ClO4)2 or [Mn(Ph-TPY)2](ClO4)2. In all three cases, the complexes present distorted octahedral coordination polyhedra and the crystal packing is determined mainly by weak C-H...π interactions. All the compounds (except for the Ni derivatives, for which FT-IR, UV-Vis and thermal analysis are reported) were fully characterized by spectroscopic (FT-IR, UV-Vis and NMR spectroscopy) and thermal (TGA-DSC, thermogravimetric analysis-differential scanning calorimetry) methods.

Repurposing of Antifungal Drug Flucytosine/Flucytosine Cocrystals for Anticancer Activity against Prostate Cancer Targeting Apoptosis and Inflammatory Signaling Pathways

This study aimed to repurpose the antifungal drug flucytosine (FCN) for anticancer activity together with cocrystals of nutraceutical coformers sinapic acid (SNP) and syringic acid (SYA). The cocrystal screening experiments with SNP resulted in three cocrystal hydrate forms in which two are polymorphs, namely, FCN-SNP F-I and FCN-SNP F-II, and the third one with different stoichiometry in the asymmetric unit (1:2:1 ratio of FCN:SNP:H2O, FCN-SNP F-III). Cocrystallization with SYA resulted in two hydrated cocrystal polymorphs, namely, FCN-SYA F-I and FCN-SYA F-II. All the cocrystal polymorphs were obtained concomitantly during the slow evaporation method, and one of the polymorphs of each system was produced in bulk by the slurry method. The interaction energy and lattice energies of all cocrystal polymorphs were established using solid-state DFT calculations, and the outcomes correlated with the experimental results. Further, the in vitro cytotoxic activity of the cocrystals was determined against DU145 prostate cancer and the results showed that the FCN-based cocrystals (FCN-SNP F-III and FCN-SYA F-I) have excellent growth inhibitory activity at lower concentrations compared with parent FCN molecules. The prepared cocrystals induce apoptosis by generating oxidative stress and causing nuclear damage in prostate cancer cells. The Western blot analysis also depicted that the cocrystals downregulate the inflammatory markers such as NLRP3 and caspase-1 and upregulate the intrinsic apoptosis signaling pathway marker proteins, such as Bax, p53, and caspase-3. These findings suggest that the antifungal drug FCN can be repurposed for anticancer activity.

Crystal structure and Hirshfeld surface analysis of (Z)-4-oxo-4-{phen-yl[(thio-phen-2-yl)meth-yl]amino}-but-2-enoic acid

In the title compound, C15H13NO3S, the mol-ecular conformation is stable with the intra-molecular O-H⋯O hydrogen bond forming a S(7) ring motif. In the crystal, mol-ecules are connected by C-H⋯O hydrogen bonds, forming C(8) chains running along the a-axis direction. Cohesion of the packing is provided by weak van der Waals inter-actions between the chains. A Hirshfeld surface analysis was undertaken to investigate and qu-antify the inter-molecular inter-actions. The thio-phene ring is disordered in a 0.9466 (17):0.0534 (17) ratio over two positions rotated by 180°.

The single-atom R1: a new optimization method to solve crystal structures

A crystal structure with N atoms in its unit cell can be solved starting from a model with atoms 1 to j - 1 being located. To locate the next atom j, the method uses a modified definition of the traditional R1 factor where its dependencies on the locations of atoms j + 1 to N are removed. This modified R1 is called the single-atom R1 (sR1), because the locations of atoms 1 to j - 1 in sR1 are the known parameters, and only the location of atom j is unknown. Finding the correct position of atom j translates thus into the optimization of the sR1 function, with respect to its fractional coordinates, xj, yj, zj. Using experimental data, it has been verified that an sR1 has a hole near each missing atom. Further, it has been verified that an algorithm based on sR1, hereby called the sR1 method, can solve crystal structures (with up to 156 non-hydrogen atoms in the unit cell). The strategy to carry out this calculation has also been optimized. The main feature of the sR1 method is that, starting from a single arbitrarily positioned atom, the structure is gradually revealed. With the user's help to delete poorly determined parts of the structure, the sR1 method can build the model to a high final quality. Thus, sR1 is a viable and useful tool for solving crystal structures.

Crystal structure and Hirshfeld surface analysis of dimethyl 2-oxo-4-(pyridin-2-yl)-6-(thio-phen-2-yl)cyclo-hex-3-ene-1,3-di-carboxyl-ate

In the title compound, C19H17NO5S, the cyclo-hexene ring adopts nearly an envelope conformation. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional network. In addition, C-H⋯π inter-actions connect the mol-ecules by forming layers parallel to the (010) plane. According to the Hirshfeld surface analysis, H⋯H (36.9%), O⋯H/H⋯O (31.0%), C⋯H/H⋯C (18.9%) and S⋯H/H⋯S (7.9%) inter-actions are the most significant contributors to the crystal packing.

Synthesis and crystal structure of the cluster (Et4N)[(Tp*)MoFe3S3(μ3-NSiMe3)(N3)3]

The title compound, tetra-ethyl-ammonium tri-azido-tri-μ3-sulfido-[μ3-(tri-methyl-sil-yl)aza-nediido][tris-(3,5-di-methyl-pyrazol-1-yl)hydro-borato]triiron(+2.33)molybdenum(IV), (C8H20N)[Fe3MoS3(C15H22BN6)(C3H9NSi)(N3)3] or (Et4N)[(Tp*)MoFe3S3(μ3-NSiMe3)(N3)3] [Tp* = tris-(3,5-di-methyl-pyrazol-1-yl)hydro-bor-ate(1-)], crystallizes as needle-like black crystals in space group P . In this cluster, the Mo site is in a distorted octa-hedral coordination model, coordinating three N atoms on the Tp* ligand and three μ3-bridging S atoms in the core. The Fe sites are in a distorted tetra-hedral coordination model, coordinating two μ3-bridging S atoms, one μ3-bridging N atom from Me3SiN2-, and another N atom on the terminal azide ligand. This type of heterometallic and heteroleptic single cubane cluster represents a typical example within the Mo-Fe-S cluster family, which may be a good reference for understanding the structure and function of the nitro-genase FeMo cofactor. The residual electron density of disordered solvent mol-ecules in the void space could not be reasonably modeled, thus the SQUEEZE [Spek (2015). Acta Cryst. C71, 9-18] function was applied. The solvent contribution is not included in the reported mol-ecular weight and density.

Discovery of indoleninyl-pyrazolo[3,4-b]pyridines as potent chemotherapeutic agents against colorectal cancer cells

A new series of indolenines decorated with pyrazolo[3,4-b]pyridines were designed and synthesized in up to 96% yield from the acid-catalyzed cyclocondensation of 1,3-dialdehydes with 3-aminopyrazoles. X-ray crystallography on a representative derivative, 5n, revealed two close to planar conformations whereby the N-atom of the pyridyl residue was syn or anti to the pyrrole-N atom in the two independent molecules of the asymmetric unit. The computational and DNA binding data suggest that 5n is a strong DNA intercalator with the results in agreement with its potent cytotoxicity against two colorectal cancer cell lines (HCT 116 and HT-29). In contrast to doxorubicin, compounds 5k-o have higher druggability (compliance to more criteria stated in Lipinski's rule of five and Veber's rule), higher bioavailability, and better medicinal chemistry properties, indicative of their potential application as chemotherapeutical agents.

The crystal structures and Hirshfeld surface analysis of three new bromo-substituted 3-methyl-1-(phenyl-sulfon-yl)-1H-indole derivatives

Three new 1H-indole derivatives, namely, 2-(bromo-meth-yl)-3-methyl-1-(phenyl-sulfon-yl)-1H-indole, C16H14BrNO2S, (I), 2-[(E)-2-(2-bromo-5-meth-oxy-phen-yl)ethen-yl]-3-methyl-1-(phenyl-sulfon-yl)-1H-indole, C24H20BrNO3S, (II), and 2-[(E)-2-(2-bromo-phen-yl)ethen-yl]-3-methyl-1-(phenyl-sulfon-yl)-1H-indole, C23H18BrNO2S, (III), exhibit nearly orthogonal orientations of their indole ring systems and sulfonyl-bound phenyl rings. Such conformations are favourable for inter-molecular bonding involving sets of slipped π-π inter-actions between the indole systems and mutual C-H⋯π hydrogen bonds, with the generation of two-dimensional monoperiodic patterns. The latter are found in all three structures, in the form of supra-molecular columns with every pair of successive mol-ecules related by inversion. The crystal packing of the compounds is additionally stabilized by weaker slipped π-π inter-actions between the outer phenyl rings (in II and III) and by weak C-H⋯O, C-H⋯Br and C-H⋯π hydrogen bonds. The structural significance of the different kinds of inter-actions agree with the results of a Hirshfeld surface analysis and the calculated inter-action energies. In particular, the largest inter-action energies (up to -60.8 kJ mol-1) are associated with pairing of anti-parallel indole systems, while the energetics of weak hydrogen bonds and phenyl π-π inter-actions are comparable and account for 13-34 kJ mol-1.

2-(10-Bromo-anthracen-9-yl)-N-phenyl-aniline

In the title compound, C26H18BrN, the central benzene ring makes dihedral angles with its adjacent anthracene ring system and pendant benzene ring of 87.49 (13) and 62.01 (17)°, respectively. The N-H moiety is sterically blocked from forming a hydrogen bond, but weak C-H⋯π inter-actions occur in the extended structure.

Synthesis, crystal structure and Hirshfeld surface analysis of (3Z)-4-[(4-amino-1,2,5-oxa-diazol-3-yl)amino]-3-bromo-1,1,1-tri-fluoro-but-3-en-2-one

In the title compound, C6H4BrF3N4O2, the oxa-diazole ring is essentially planar with a maximum deviation of 0.003 (2) Å. In the crystal, mol-ecular pairs are connected by N-H⋯N hydrogen bonds, forming dimers with an R 2 2(8) motif. The dimers are linked into layers parallel to the (10) plane by N-H⋯O hydrogen bonds. In addition, C-O⋯π and C-Br⋯π inter-actions connect the mol-ecules, forming a three-dimensional network. The F atoms of the tri-fluoro-methyl group are disordered over two sites in a 0.515 (6): 0.485 (6) ratio. The inter-molecular inter-actions in the crystal structure were investigated and qu-anti-fied using Hirshfeld surface analysis.

Crystal structure and Hirshfeld surface analysis of 3,3'-[ethane-1,2-diylbis(-oxy)]bis-(5,5-di-methyl-cyclo-hex-2-en-1-one) including an unknown solvate

The title mol-ecule, C18H26O4, consists of two symmetrical halves related by the inversion centre at the mid-point of the central -C-C- bond. The hexene ring adopts an envelope conformation. In the crystal, the mol-ecules are connected into dimers by C-H⋯O hydrogen bonds with R 2 2(8) ring motifs, forming zigzag ribbons along the b-axis direction. According to a Hirshfeld surface analysis, H⋯H (68.2%) and O⋯H/H⋯O (25.9%) inter-actions are the most significant contributors to the crystal packing. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015 ▸). Acta Cryst. C71, 9-18] in PLATON. The solvent contribution was not included in the reported mol-ecular weight and density.

Ilmenite-type Na2(Fe2/3Te4/3)O6

Na2(Fe2/3Te4/3)O6 (Z = 3) or Na3(FeTe2)O9 (Z = 2), tris-odium iron(III) ditellurium(VI) nona-oxide, adopts the ilmenite (FeTiO3, Z = 6) structure type with the Ti site (site symmetry 3.) replaced by Na and the Fe site (site symmetry 3.) replaced by a mixed-occupied (FeIII,TeVI) site in a Fe:Te ratio of 1:2. Whereas the [(Fe,Te)O6] octa-hedron is only slightly distorted, the [NaO6] octa-hedron shows much stronger distortions, as revealed by a larger spread of the bond lengths and some distortion parameters.

Ethyl 2-[(2-oxo-2H-chromen-6-yl)-oxy]acetate

Ethyl 2-[(2-oxo-2H-chromen-6-yl)-oxy]acetate, C13H12O5, a member of the pharmacologically important class of coumarins, crystallizes in the monoclinic C2/c space group in the form of sheets, within which mol-ecules are related by inversion centers and 21 axes. Multiple C-H⋯O weak hydrogen-bonding inter-actions reinforce this pattern. The planes of these sheets are oriented in the approximate direction of the ac face diagonal. Inter-sheet inter-actions are a combination of coumarin system π-π stacking and additional C-H⋯O weak hydrogen bonds between ethyl acet-oxy groups.

Artificial Intelligence Driving Materials Discovery? Perspective on the Article: Scaling Deep Learning for Materials Discovery

The discovery of new crystalline inorganic compounds-novel compositions of matter within known structure types, or even compounds with completely new crystal structures-constitutes an important goal of solid-state and materials chemistry. Some fractions of new compounds can eventually lead to new structural and functional materials that enhance the efficiency of existing technologies or even enable completely new technologies. Materials researchers eagerly welcome new approaches to the discovery of new compounds, especially those that offer the promise of accelerated success. The recent report from a group of scientists at Google who employ a combination of existing data sets, high-throughput density functional theory calculations of structural stability, and the tools of artificial intelligence and machine learning (AI/ML) to propose new compounds is an exciting advance. We examine the claims of this work here, unfortunately finding scant evidence for compounds that fulfill the trifecta of novelty, credibility, and utility. While the methods adopted in this work appear to hold promise, there is clearly a great need to incorporate domain expertise in materials synthesis and crystallography.

Crystal structure, intermolecular interactions, charge-density distribution and ADME properties of the acridinium 4-nitrobenzoate and 2-amino-3-methylpyridinium 4-nitrobenzoate salts: a combined experimental and theoretical study

Acridines are a class of bioactive agents which exhibit high biological stability and the ability to intercalate with DNA; they have a wide range of applications. Pyridine derivatives have a wide range of biological activities. To enhance the properties of acridine and 2-amino-3-methylpyridine as the active pharmaceutical ingredient (API), 4-nitrobenzoic acid was chosen as a coformer. In the present study, a mixture of acridine and 4-nitrobenzoic acid forms the salt acridinium 4-nitrobenzoate, C13H10N+·C7H4NO4- (I), whereas a mixture of 2-amino-3-methylpyridine and 4-nitrobenzoic acid forms the salt 2-amino-3-methylpyridinium 4-nitrobenzoate, C6H9N2+·C7H4NO4- (II). In both salts, protonation takes place at the ring N atom. The crystal structure of both salts is predominantly governed by hydrogen-bond interactions. In salt I, C-H...O and N-H...O interactions form an infinite chain in the crystal, whereas in salt II, intermolecular N-H...O interactions form an eight-membered R22(8) ring motif. A theoretical charge-density analysis reveals the charge-density distribution of the inter- and intramolecular interactions of both salts. An in-silico ADME analysis predicts the druglikeness properties of both salts and the results confirm that both salts are potential drug candidates with good bioavailability scores and there is no violation of the Lipinski rules, which supports the druglikeness properties of both salts. However, although both salts exhibit drug-like properties, salt I has higher gastrointestinal absorption than salt II and hence it may be considered a potential drug candidate.

Crystal structure solution and high-temperature thermal expansion in NaZr2(PO4)3-type materials

The NaZr2P3O12 family of materials have shown low and tailorable thermal expansion properties. In this study, SrZr4P6O24 (SrO·4ZrO2·3P2O5), CaZr4P6O24 (CaO·4ZrO2·3P2O5), MgZr4P6O24 (MgO·4ZrO2·3P2O5), NaTi2P3O12 [½(Na2O·4TiO2·3P2O5)], NaZr2P3O12 [½(Na2O·4ZrO2·3P2O5)], and related solid solutions were synthesized using the organic-inorganic steric entrapment method. The samples were characterized by in-situ high-temperature X-ray diffraction from 25 to 1500°C at the Advanced Photon Source and National Synchrotron Light Source II. The average linear thermal expansion of SrZr4P6O24 and CaZr4P6O24 was between -1 × 10-6 per °C and 6 × 10-6 per °C from 25 to 1500°C. The crystal structures of the high-temperature polymorphs of CaZr4P6O24 and SrZr4P6O24 with R3c symmetry were solved by Fourier difference mapping and Rietveld refinement. This polymorph is present above ∼1250°C. This work measured thermal expansion coefficients to 1500°C for all samples and investigated the differences in thermal expansion mechanisms between polymorphs and between compositions.

A twofold interpenetrated two-dimensional zinc(II) coordination polymer for the highly sensitive detection of nitrofurantoin in aqueous medium

A novel ZnII coordination polymer, namely, poly[{μ2-bis[4-(2-methyl-1H-imidazol-1-yl)phenyl]methanone-κ2N3:N3'}(μ2-5-bromobenzene-1,3-dicarboxylato-κ2O1:O3)zinc(II)], [Zn(C8H3BrO4)(C21H18N4O)]n or [Zn(Br-BDC)(MIPMO)]n, (I), has been synthesized by the solvothermal method using 5-bromoisophthalic acid (Br-H2BDC), bis[4-(2-methyl-1H-imidazol-1-yl)phenyl]methanone (MIPMO) and Zn(NO3)2·6H2O. Structure analysis showed that compound (I) displays twofold parallel interwoven sql nets. Fluorescence experiments confirmed that the compound can sensitively and selectively detect nitrofurantoin (NFT) in aqueous medium. In addition, the possible fluorescence quenching mechanisms of compound (I) toward NFT are investigated.

Synthesis, crystal structure and in-silico evaluation of arylsulfonamide Schiff bases for potential activity against colon cancer

This report presents a comprehensive investigation into the synthesis and characterization of Schiff base compounds derived from benzenesulfonamide. The synthesis process, involved the reaction between N-cycloamino-2-sulfanilamide and various substituted o-salicylaldehydes, resulted in a set of compounds that were subjected to rigorous characterization using advanced spectral techniques, including 1H NMR, 13C NMR and FT-IR spectroscopy, and single-crystal X-ray diffraction. Furthermore, an in-depth assessment of the synthesized compounds was conducted through Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) analysis, in conjunction with docking studies, to elucidate their pharmacokinetic profiles and potential. Impressively, the ADMET analysis showcased encouraging drug-likeness properties of the newly synthesized Schiff bases. These computational findings were substantiated by molecular properties derived from density functional theory (DFT) calculations using the B3LYP/6-31G* method within the Jaguar Module of Schrödinger 2023-2 from Maestro (Schrodinger LLC, New York, USA). The exploration of frontier molecular orbitals (HOMO and LUMO) enabled the computation of global reactivity descriptors (GRDs), encompassing charge separation (Egap) and global softness (S). Notably, within this analysis, one Schiff base, namely, 4-bromo-2-{N-[2-(pyrrolidine-1-sulfonyl)phenyl]carboximidoyl}phenol, 20, emerged with the smallest charge separation (ΔEgap = 3.5780 eV), signifying heightened potential for biological properties. Conversely, 4-bromo-2-{N-[2-(piperidine-1-sulfonyl)phenyl]carboximidoyl}phenol, 17, exhibited the largest charge separation (ΔEgap = 4.9242 eV), implying a relatively lower propensity for biological activity. Moreover, the synthesized Schiff bases displayed remarkeable inhibition of tankyrase poly(ADP-ribose) polymerase enzymes, integral in colon cancer, surpassing the efficacy of a standard drug used for the same purpose. Additionally, their bioavailability scores aligned closely with established medications such as trifluridine and 5-fluorouracil. The exploration of molecular electrostatic potential through colour mapping delved into the electronic behaviour and reactivity tendencies intrinsic to this diverse range of molecules.

Silver Coordination Polymers Driven by Adamantoid Blocks for Advanced Antiviral and Antibacterial Biomaterials

The development of sustainable biomaterials and surfaces to prevent the accumulation and proliferation of viruses and bacteria is highly demanded in healthcare areas. This study describes the assembly and full characterization of two new bioactive silver(I) coordination polymers (CPs) formulated as [Ag(aca)(μ-PTA)]n·5nH2O (1) and [Ag2(μ-ada)(μ3-PTA)2]n·4nH2O (2). These products were generated by exploiting a heteroleptic approach based on the use of two different adamantoid building blocks, namely 1,3,5-triaza-7-phosphaadamantane (PTA) and 1-adamantanecarboxylic (Haca) or 1,3-adamantanedicarboxylic (H2ada) acids, resulting in the assembly of 1D (1) and 3D (2). Antiviral, antibacterial, and antifungal properties of the obtained compounds were investigated in detail, followed by their incorporation as bioactive dopants (1 wt %) into hybrid biopolymers based on acid-hydrolyzed starch polymer (AHSP). The resulting materials, formulated as 1@AHSP and 2@AHSP, also featured (i) an exceptional antiviral activity against herpes simplex virus type 1 and human adenovirus (HAd-5) and (ii) a remarkable antibacterial activity against Gram-negative bacteria. Docking experiments, interaction with human serum albumin, mass spectrometry, and antioxidation studies provided insights into the mechanism of antimicrobial action. By reporting these new silver CPs driven by adamantoid building blocks and the derived starch-based materials, this study endows a facile approach to access biopolymers and interfaces capable of preventing and reducing the proliferation of a broad spectrum of different microorganisms, including bacteria, fungi, and viruses.

6-Aryl-4-cycloamino-1,3,5-triazine-2-amines: synthesis, antileukemic activity, and 3D-QSAR modelling

Despite significant progress in immunotherapy and chimeric antigen receptor T cell therapy of leukemia, chemotherapy is the major treatment option for the disease. Therefore, the development of potent and safe drugs for standard and targeted chemotherapy of leukemia remains an important task for medicinal chemists. A library of 94 diverse 6-aryl-4-cycloamino-1,3,5-triazine-2-amines was prepared using a one-pot microwave-assisted protocol, which involves a three-component reaction of cyanoguanidine, aromatic aldehydes and cyclic amines, and subsequent dehydrogenative aromatization of the dihydrotriazine intermediates in the presence of alkali. The cytotoxic properties of prepared compounds were evaluated against the leukemic Jurkat T cell line and the selectivity of the 24 most active compounds was also assessed using a normal fibroblast MRC-5 cell line, indicating selective antiproliferative activity against leukemic cells. The structure-activity relationship was analysed, and the prepared 3D-QSAR model was found to predict the antileukemic activity of the compounds with reasonable accuracy. In the cell morphology study, both apoptosis and necrosis features were observed in Jurkat T cells after treatment with the most active compound.

Combination of Hydrogen and Halogen Bonds in the Crystal Structures of 5-Halogeno-1H-isatin-3-oximes: Involvement of the Oxime Functionality in Halogen Bonding

Various functional groups have been considered as acceptors for halogen bonds, but the oxime functionality has received very little attention in this context. In this study, we focus on the analysis of the hydrogen and halogen bond preferences observed in the crystal structures of 5-halogeno-1H-isatin-3-oximes. These molecules can be involved in various non-covalent interactions, and the competition between these interactions has a decisive influence on their self-organization. In particular, we were interested to see whether the crystal structures of 5-halogeno-1H-isatin-3-oximes, especially bromine- and iodine-substituted ones, are characterized by the presence of halogen bonds formed with the oxime functionality. The oxime group proved its ability to compete with the other strong donor and acceptor sites by participating in the formation of cyclic hydrogen-bonded heterosynthons oxime∙∙∙amide and Ooxime∙∙∙Br/I halogen bonds.

Syntheses, characterizations, crystal structures and Hirshfeld surface analyses of methyl 4-[4-(di-fluorometh-oxy)phen-yl]-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, isopropyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate and tert-butyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate

The crystal structures and Hirshfeld surface analyses of three similar compounds are reported. Methyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, (C21H23F2NO4), (I), crystallizes in the monoclinic space group C2/c with Z = 8, while isopropyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carb-oxyl-ate, (C23H27F2NO4), (II) and tert-butyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, (C24H29F2NO4), (III) crystallize in the ortho-rhom-bic space group Pbca with Z = 8. In the crystal structure of (I), mol-ecules are linked by N-H⋯O and C-H⋯O inter-actions, forming a tri-periodic network, while mol-ecules of (II) and (III) are linked by N-H⋯O, C-H⋯F and C-H⋯π inter-actions, forming layers parallel to (002). The cohesion of the mol-ecular packing is ensured by van der Waals forces between these layers. In (I), the atoms of the 4-di-fluoro-meth-oxy-phenyl group are disordered over two sets of sites in a 0.647 (3): 0.353 (3) ratio. In (III), the atoms of the dimethyl group attached to the cyclo-hexane ring, and the two carbon atoms of the cyclo-hexane ring are disordered over two sets of sites in a 0.646 (3):0.354 (3) ratio.

Methyl N-{(1R)-2-[(meth-oxy-carbon-yl)-oxy]-1-phenyleth-yl}carbamate

The title mol-ecule, C12H15NO5, is a methyl carbamate derivative obtained by reacting (R)-2-phenyl-glycinol and methyl chloro-formate, with calcium hydroxide as heterogeneous catalyst. Supra-molecular chains are formed in the [100] direction, based on N-H⋯O hydrogen bonds between the amide and carboxyl-ate groups. These chains weakly inter-act in the crystal, and the phenyl rings do not display significant π-π inter-actions.

Synthesis, crystal structure and Hirshfeld surface analysis of 2-phenyl-3-(prop-2-yn-1-yl-oxy)quin-oxaline

In the title compound, C17H12N2O, the quinoxaline moiety shows deviations of 0.0288 (7) to -0.0370 (7) Å from the mean plane (r.m.s. deviation of fitted atoms = 0.0223 Å). In the crystal, corrugated layers two mol-ecules thick are formed by C-H⋯N hydrogen bonds and π-stacking inter-actions.

Crystal structure and Hirshfeld surface analysis of 4-oxo-3-phenyl-2-sulfanyl-idene-5-(thio-phen-2-yl)-3,4,7,8,9,10-hexa-hydro-2H-pyrido[1,6-a:2,3-d']di-pyrimidine-6-carbo-nitrile

In the title compound, C21H15N5OS2, mol-ecular pairs are linked by N-H⋯N hydrogen bonds along the c-axis direction and C-H⋯S and C-H⋯O hydrogen bonds along the b-axis direction, with R 2 2(12) and R 2 2(16) motifs, respectively, thus forming layers parallel to the (10) plane. In addition, C=S⋯π and C≡N⋯π inter-actions between the layers ensure crystal cohesion. The Hirshfeld surface analysis indicates that the major contributions to the crystal packing are H⋯H (43.0%), C⋯H/H⋯C (16.9%), N⋯H/H⋯N (11.3%) and S⋯H/H⋯S (10.9%) inter-actions.

Crystal structure and Hirshfeld surface analysis of 6-imino-8-(4-methyl-phen-yl)-1,3,4,6-tetra-hydro-2H-pyrido[1,2-a]pyrimidine-7,9-dicarbo-nitrile

In the ten-membered 1,3,4,6-tetra-hydro-2H-pyrido[1,2-a]pyrimidine ring system of the title compound, C17H15N5, the 1,2-di-hydro-pyridine ring is essentially planar (r.m.s. deviation = 0.001 Å), while the 1,3-diazinane ring has a distorted twist-boat conformation. In the crystal, mol-ecules are linked by N-H⋯N and C-H⋯N hydrogen bonds, forming a three-dimensional network. In addition, C-H⋯π inter-actions form layers parallel to the (100) plane. Thus, crystal-structure cohesion is ensured. According to a Hirshfeld surface study, H⋯H (40.4%), N⋯H/H⋯N (28.6%) and C⋯H/H⋯C (24.1%) inter-actions are the most important contributors to the crystal packing.

Crystal structure and Hirshfeld surface analysis of 8-benzyl-1-[(4-methyl-phen-yl)sulfon-yl]-2,7,8,9-tetra-hydro-1H-3,6:10,13-diep-oxy-1,8-benzodi-aza-cyclo-penta-decine ethanol hemisolvate

The asymmetric unit of the title compound, 2C31H28N2O4S·C2H6O, contains a parent mol-ecule and a half mol-ecule of ethanol solvent. The main compound stabilizes its mol-ecular conformation by forming a ring with an R 1 2(7) motif with the ethanol solvent mol-ecule. In the crystal, mol-ecules are connected by C-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional network. In addition, C-H⋯π inter-actions also strengthen the mol-ecular packing.