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C50H44Cl4CoF2N2P2, orthorhombic, Pbca (no. 61), a = 18.4662(6) Å, b = 15.2888(5) Å, c = 33.2661(10) Å, V = 9391.9(5) Å3, Z = 8, Rgt(F) = 0.0403, wRref(F2) = 0.1005, T = 180.0(5) K.

The title compound, C 5 H 2 Cl 3 NO, is almost planar. In the crystal, the mol-ecules form centrosymmetric hydrogen-bonded dimers through pairwise O-H⋯N inter-actions to generate R 2 2 (8) loops., (© Vaughn et al. 2024.)

The phytochemical investigation of the MeOH extract of Astragalus condensatus roots led to the discovery of a new tetrahydropyran cycloartane-type triterpenoid, astracondensatol A ( 1 ), alongside six known cyclocephagenol derivatives ( 2 , 3 , 20 , 32 , 35 , and 36 ). Elucidation of their structures involved 1D and 2D-NMR spectroscopy and mass data analysis. Upon comparing NMR spectroscopic data with prior literature, several carbon shift anomalies, particularly at C-24, prompted a reevaluation using quantum chemical calculations, resulting in the revision of the 24 S to 24 R absolute configuration for compound 2 and 38 other reported cyclocephagenol-type triterpenoids. X-ray crystallography data further supported the analysis in establishing the absolute configuration of compound 2 . Ambiguous NOE correlations and publication bias could have played a significant role in miss-assigning the C-24 absolute configuration in tetrahydropyran cycloartane-type triterpenoids.

The title hydrated mol-ecular salt, C 19 H 15 N 4 + ·Cl - ·2.5H 2 O, has two tri-phenyl-tetra-zolium cations, two chloride anions and five water mol-ecules in the asymmetric unit. The cations differ in the conformations of the phenyl rings with respect to the heterocyclic core, most notably for the C-bonded phenyl ring, for which the N-C-C-C torsion angles differ by 36.4 (3)°. This is likely a result of one cation accepting an O-H⋯N hydrogen bond from a water mol-ecule [O⋯N = 3.1605 (15) Å], while the other cation accepts no hydrogen bonds. In the extended structure, the water mol-ecules are involved in centrosymmetric (H 2 O) 2 Cl 2 rings as well as (H 2 O) 4 chains. An unusual O-H⋯π inter-action and weak C-H⋯O and C-H⋯Cl hydrogen bonds are also observed., (© Uppu et al. 2024.)

The title compound, [Re(C 17 H 22 N 3 O 2 S)(CO) 3 ] is a net neutral fac -Re(I)(CO) 3 complex of the 4-methyl-biphenyl sulfonamide derivatized di-ethyl-enetri-amine ligand. The NNN-donor monoanionic ligand coordinates with the Re core in tridentate fashion, establishing an inner coordination sphere resulting in a net neutral complex. The complex possesses pseudo-octa-hedral geometry where one face of the octa-hedron is occupied by three carbonyl ligands and the other faces are occupied by one sp 2 nitro-gen atom of the sulfonamide group and two sp 3 nitro-gen atoms of the dien backbone. The Re-N sp 2 bond distance, 2.173 (4) Å, is shorter than the Re-N sp 3 bond distances, 2.217 (5) and 2.228 (6) Å, and is similar to the range reported for typical Re-N sp 2 bond lengths (2.14 to 2.18 Å)., (© Kaluthanthiri et al. 2024.)

The oxidation of me-thionyl peptides can contribute to increased biological (oxidative) stress and development of various inflammatory diseases. The conformation of peptides has an important role in the mechanism of oxidation and the inter-mediates formed in the reaction. Herein, the crystal structures of the isomeric dipeptides Gly-Met (Gly = glycine and Met = me-thio-nine) and Met-Gly, both C 7 H 14 N 2 O 3 S, are reported. Both mol-ecules exist in the solid state as zwitterions with nominal proton transfer from the carb-oxy-lic acid to the primary amine group. The Gly-Met mol-ecule has an extended backbone structure, while Met-Gly has two nearly planar regions kinked at the C atom bearing the NH 3 group. In the crystals, both structures form extensive three-dimensional hydrogen-bonding networks via N-H⋯O and bifurcated N-H⋯(O,O) hydrogen bonds having N⋯O distances in the range 2.6619 (13)-2.8513 (13) Å for Gly-Met and 2.6273 (8)-3.1465 (8) Å for Met-Gly., (© Babu et al. 2024.)

The synthesis of a new bis-BF 2 tetrafluorobenzo-[α]-fused BOPYPY dye from 4,5,6,7-tetrafluoroisoindole and 2-hydrazinopyrazine is reported. The regioselectivity of nucleophilic substitution reactions at the periphery of the tetrafluorinated BOPYPY and its α-bromo derivative were investigated using N-, O-, S-, and C-based nucleophiles. Among the aromatic fluorine atoms, the F 2 atom is consistently regioselectively substituted, except when the α-position contains a thiophenol group; in this case, F 4 is substituted instead due to stabilizing π-π-stacking between the two aromatic groups. The α-bromo BOPYPY derivative also reacts under Stille cross-coupling reaction conditions to produce the corresponding α-substituted product. The spectroscopic properties of these new fluorinated BOPYPYs were investigated and compared with nonfluorinated analogs.

The structure of the title compound, C 9 H 10 OTe, at 100 K has ortho-rhom-bic ( P 2 1 2 1 2) symmetry with two independent mol-ecules in the asymmetric unit ( Z ' = 2). The mol-ecules are folded along their Te⋯O axes, with their Te-C-O planes angled at an average of 25.1° with respect to the remaining non-H atoms, which are almost coplanar (average deviation from planarity = 0.04 Å). A Hirshfeld plot shows weak inter-molecular inter-actions between the two Te atoms located in each asymmetric mol-ecule, with a Te⋯Te distance of 3.7191 (4) Å. The structure is strongly pseudosymmetric to the space group Pccn with Z ' = 1. The crystal chosen for data collection was found to be was an inversion twin., (© Ponzo et al. 2024.)

At room temperature, the title salt, C 7 H 10 NO + ·Cl - , is ortho-rhom-bic, space group Pbca with Z ' = 1, as previously reported [Zhao (2009 ▸). Acta Cryst. E 65 , o2378]. Between 250 and 200 K, there is a solid-state phase transition to a twinned monoclinic P 2 1 / c structure with Z ' = 2. We report the high temperature structure at 250 K and the low-temperature structure at 100 K. In the low-temperature structure, the -NH 3 hydrogen atoms are ordered and this group has a different orientation in each independent mol-ecule, in keeping with optimizing N-H⋯Cl hydrogen bonding, some of which are bifurcated: these hydrogen bonds have N⋯Cl distances in the range 3.1201 (8)-3.4047 (8) Å. In the single cation of the high-temperature structure, the NH hydrogen atoms are disordered into the average of the two low-temperature positions and the N⋯Cl hydrogen bond distances are in the range 3.1570 (15)-3.3323 (18) Å. At both temperatures, the meth-oxy group is nearly coplanar with the rest of the mol-ecule, with the C-C-O-C torsion angles being -7.0 (2)° at 250 K and -6.94 (12) and -9.35 (12)° at 100 K. In the extended ortho-rhom-bic structure, (001) hydrogen-bonded sheets occur; in the monoclinic structure, the sheets propagate in the (010) plane., (© Uppu et al. 2024.)

The reaction of Zn ions with β-octaalkylcorroles leads to the air oxidation of the macrocycle, with the formation of a mixture of 5- and 10-oxocorroles. Spectroscopic characterization confirms the antiaromatic character of these macrocycles. A simple synthetic protocol opens the way for more detailed studies of oxocorrole chemistry.

Alkylation of one of the inner-core nitrogen atoms is one possible approach to obtain dianionic corrole ligands, suitable for the coordination of divalent metal ions, such as Pd II . Inner-core N-methylation can be obtained by treating the corrole with CH 3 I, but the reaction conditions should be optimized to limit the formation of the dimethylated derivative. Two regioisomers, the N-21 and the N-22 methyl derivatives are obtained from the reaction, with the first product achieved in a higher amount. Structural characterization of the reaction products evidenced the distortion induced by the introduction of the methyl groups; the N-methylcorroles are chiral compounds, and the enantiomers were separated by chromatography, with their absolute configuration assigned by ECD computation. Palladium insertion was achieved in the case of monosubstituted corroles, but not with the dimethylated macrocycle; X-ray characterization of the complexes showed the distortion of the macrocycles. The Pd complexes do not show luminescence emission, but are able to produce singlet oxygen upon irradiation. The Pd II complexes were also inserted in human serum albumin (HSA) and dispersed in water; in this case, the protein protects the corroles from photobleaching, and a switch from the type II to the type I mechanism in reactive oxygen species (ROS) production is observed., (© 2023 Wiley-VCH GmbH.)

We report an enantioselective synthesis of cyclic ketones with full substitutions at the α-positions in a highly diastereoselective manner. Our method is achieved by subjecting substrate motifs in 2-allyloxyenones to chiral organomagnesium reagents, which trigger the Claisen rearrangement upon direct 1,2-carbonyl addition. The observed diastereoselectivity of the allyl migration is proposed to originate from the intramolecular chelation of the magnesium alkoxide to the allyloxy moiety.

The reaction between CpRu(PPh 3 ) 2 NCS (1a) and PMePh 2 yields CpRu(PPh 3 )(PMePh 2 )NCS (2a) while CpRu(PPh 3 )(PMePh 2 )Cl reacts with SCN - to form the S-bonded isomer, CpRu(PPh 3 )(PMePh 2 )SCN (2b). Compound 1a and the linkage isomers of 2 were characterized by X-ray crystallography. The kinetics of the reaction between 1a and PMePh 2 under pseudo-first order conditions in THF and in fluorobenzene to form 2a are consistent with a dissociative interchange mechanism. Activation parameters for the reaction are: Δ H † = 15.7 ± 0.6 kcal mol -1 and Δ S † = -35 ± 2 cal mol -1 K -1 in THF vs. Δ H † = 24.8 ± 1.2 kcal mol -1 and Δ S † = -6 ± 4 cal mol -1 K -1 in C 6 H 5 F. In the presence of added SCN - , the rate of phosphine substitution is unchanged but a mixture of 2a and 2b is observed. The selenocyanate derivative, CpRu(PPh 3 ) 2 SeCN (3b), crystallizes as the Se-bonded linkage isomer. Compound 3b reacts with PMePh 2 under pseudo-first order conditions in fluorobenzene to form CpRu(PPh 3 )(PMePh 2 )SeCN (4b) at a much faster rate than 1a with activation parameters: Δ H † = 30.9 ± 4.8 kcal mol -1 and Δ S † = 22.4 ± 15.9 cal mol -1 K -1 with no evidence for linkage isomerization to the N-bonded products.

[HCo(CO) x (bisphosphine)](BF 4 ), x = 1-3, is a highly active hydroformylation catalyst system, especially for internal branched alkenes. In situ infrared spectroscopy (IR), electron paramagnetic resonance (EPR), and nuclear magnetic resonance studies support the proposed catalyst formulation. IR studies reveal the formation of a dicationic Co(I) paramagnetic CO-bridged dimer, [Co 2 (μ-CO) 2 (CO)(bisphosphine) 2 ] 2+ , at lower temperatures formed from the reaction of two catalyst complexes via the elimination of H 2 . DFT studies indicate a dimer structure with square-pyramidal and tetrahedral cobalt centers. This monomer-dimer equilibrium is analogous to that seen for HCo(CO) 4 , reacting to eliminate H 2 and form Co 2 (CO) 8 . EPR studies on the catalyst show a high-spin ( S = 3/2) Co(II) complex. Reaction studies are presented that support the cationic Co(II) bisphosphine catalyst as the catalyst species present in this system and minimize the possible role of neutral Co(I) species, HCo(CO) 4 or HCo(CO) 3 (phosphine), as catalysts.

The title compound, C 12 H 15 NO 3 , crystallizes with Z ' = 2 in space group Pca 2 1 with the two independent mol-ecules having almost the same conformation, differing mostly at the end of the butanamide chain. A local inversion center near 1/8, 3/4, z relates the two mol-ecules, as is common for structures in this space group with Z ' = 2. The mol-ecule crystallizes as the keto tautomer, and the β-diketone moieties are twisted out of planarity, with O-C⋯C-O pseudo torsion angles of -74.4 (5) and -83.9 (5)°. The N-H group of each independent mol-ecule donates an inter-molecular hydrogen bond to an amide carbonyl oxygen atom by positive or negative translations along the b axis, thus forming anti-parallel chains propagating in the [010] direction., (© Yerramsetty et al. 2023.)

The study of the oxidation of various proteins necessitates scrutiny of the amino acid sequence. Since me-thio-nine (Met) and tyrosine (Tyr) are easily oxidized, peptides that contain these amino acids are frequently studied using a variety of oxidation methods, including, but not limited to, pulse radiolysis, electrochemical oxidation, and laser flash photolysis. To date, the oxidation of the Met-Tyr dipeptide is not fully understood. Several investigators have proposed a mechanism of intra-molecular electron transfer between the sulfide radical of Met and the Tyr residue. Our elucidation of the structure and absolute configuration of l-Met-l-Tyr monohydrate, C 14 H 20 N 2 O 4 S·H 2 O (systematic name: (2 S )-2-{[(2 S )-2-amino-4-methyl-sulfanyl-butano-yl]amino}-3-(4-hy-droxy-phen-yl)propanoic acid monohydrate) is presented herein and provides information about the zwitterionic nature of the dipeptide. We suspect that the zwitterionic state of the dipeptide and its inter-action within the solvent medium may play a major role in the oxidation of the dipeptide. In the crystal, all the potential donor atoms inter-act via strong N-H⋯O, C-H⋯O, O-H⋯S, and O-H⋯O hydrogen bonds., (© Babu et al. 2023.)

The introduction of electron-withdrawing groups on 8( meso )-pyridyl-BODIPYs tends to increase the fluorescence quantum yields of this type of compound due to the decrease in electronic charge density on the BODIPY core. A new series of 8( meso )-pyridyl-BODIPYs bearing a 2-, 3-, or 4-pyridyl group was synthesized and functionalized with nitro and chlorine groups at the 2,6-positions. The 2,6-methoxycarbonyl-8-pyridyl-BODIPYs analogs were also synthesized by condensation of 2,4-dimethyl-3-methoxycarbonyl-pyrrole with 2-, 3-, or 4-formylpyridine followed by oxidation and boron complexation. The structures and spectroscopic properties of the new series of 8( meso )-pyridyl-BODIPYs were investigated both experimentally and computationally. The BODIPYs bearing 2,6-methoxycarbonyl groups showed enhanced relative fluorescence quantum yields in polar organic solvents due to their electron-withdrawing effect. However, the introduction of a single nitro group significantly quenched the fluorescence of the BODIPYs and caused hypsochromic shifts in the absorption and emission bands. The introduction of a chloro substituent partially restored the fluorescence of the mono-nitro-BODIPYs and induced significant bathochromic shifts.

The photoreactivity of d 0 metal dioxo complexes in activating C-H bonds has been recently studied. [1-3] We have previously reported that MoO 2 Cl 2 (bpy- t Bu) is an effective platform for light initiated C-H activation with unique product selectivity for the overall functionalization. [1] Herein we expand on these studies and report the synthesis and photoreactivity of several new Mo(VI) dioxo complexes with the general formula MoO 2 (X) 2 (NN); where X=F - , Cl - , Br - , CH 3 - , PhO - , t BuO - and NN=2,2'-bipyridine (bpy) or 4,4'-tert-butyl-2,2'bipyridine (bpy- t Bu). Among these compounds, MoO 2 Cl 2 (bpy- t Bu) and MoO 2 Br 2 (bpy- t Bu) are able to participate in bimolecular photoreactivity with several substrates containing C-H bonds of various types such as allyls, benzyls, aldehydes (RCHO) and alkanes. MoO 2 (CH 3 ) 2 bpy and MoO 2 (PhO) 2 bpy do not participate in bimolecular photoreactions and instead they undergo photodecompositions. Computational studies indicate that the nature of the HOMO and LUMO is critical in supporting photoreactivity, with access to an LMCT (bpy→Mo) being necessary for tractable hydrocarbon functionalization., (© 2023 Wiley-VCH GmbH.)

We report the use of nitrone C-H groups as hydrogen bond donors for binding anions. Acyclic anion receptors with two nitrone moieties were synthesized by condensation reactions between aryl-aldehydes and m -phenylenedihydroxylamines. The solid-state structure of dinitrones revealed C-H⋯O hydrogen bonds. Anion binding properties were investigated using NMR titration with halide and phosphate salts.

The title compound, C 9 H 10 N 2 O 4 , crystallizes with a disordered nitro group in twinned crystals. Both the meth-oxy group and the acetamide groups are nearly coplanar with the phenyl ring, and the C-N-C-O torsion angle [0.2 (4)°] is also insignificantly different from zero. Overall, the 12-atom meth-oxy-phenyl-acetamide group is nearly planar, with an r.m.s. deviation of 0.042 Å. The nitro group is twisted out of this plane by about 30°, disordered into two orientations with opposite senses of twist. In the crystal, the N-H group donates a hydrogen bond to a nitro oxygen atom, generating chains propagating in the [101] direction. The amide carbonyl oxygen atom is not involved in the hydrogen bonding., (© Hines III et al. 2023.)

In the title compound, racemic bucetin [systematic name: N -(4-eth-oxy-phen-yl)-3-hydroxy-butanamide], C 12 H 17 NO 3 , the mol-ecule is in an extended conformation as illustrated by the C-O-C-C torsion angle [170.14 (15)°] in the eth-oxy group and the subsequent C-N-C-C [-177.24 (16)°], N-C-C-C [170.08 (15)°] and C-C-C-C [171.41 (15)°] torsion angles in the butanamide chain. In the crystal, the O-H group donates an inter-molecular O-H⋯O hydrogen bond to the amide carbonyl oxygen atom and also accepts an inter-molecular N-H⋯O hydrogen bond from an adjacent N-H group. The former forms 12-membered dimeric rings about inversion centers, and the latter form chains in the [001] direction. The overall hydrogen-bonded network is two-dimensional, with no propagation in the [100] direction., (© Hines III et al. 2023.)

The structure of the title compound, C 10 H 6 N 4 O 2 , reported by Smalley et al. [(2021). Cryst. Growth Des. 22 , 524-534] from powder diffraction data and 15 N NMR spectroscopy, is confirmed using low-temperature data from a twinned crystal. The tautomer in the solid state is alloxazine (1 H -benzo[ g ]pteridine-2,4-dione) rather than isoalloxazine (10 H -benzo[ g ]pteridine-2,4-dione). In the extended structure, the mol-ecules form hydrogen-bonded chains propagating in the [01] direction through alternating centrosymmetric R 2 2 (8) rings with pairwise N-H⋯O inter-actions and centrosymmetric R 2 2 (8) rings with pairwise N-H⋯N inter-actions. The crystal chosen for data collection was found to be a non-merohedral twin (180° rotation about [001]) in a 0.446 (4):0.554 (6) domain ratio., (© Uppu and Fronczek 2023.)

MoO 2 Cl 2 (bpy- t Bu) ( 1 ) is shown to be a potent one-electron oxidant upon irradiation with 365 nm light in various solvents, while being a weak two-electron oxidant in the dark. Complex 1 is characterized to activate various types of C-H bonds photochemically, including allylic and benzylic positions as well as alkanes and aldehydes. In all of these oxidations, 1 ultimately forms a bimetallic Mo(V)/Mo(V) species with a μ-oxo ligand ( 2 ). Depending on the substrate, the major organic product is identified as either an oxygenated or a C-C coupled (homodimerized) compound along with a minor chlorinated species. The product selectivity is proposed to be dependent upon the relative values between the bond dissociation enthalpy (BDE) of a potentially new C-OH bond within the product versus the BDE of a Mo-OH motif within a Mo(V)O(OH) intermediate. Based on this, we can estimate the BDE for Mo-OH to be 83-93 kcal/mol. Mechanistic studies suggest that the C-H activation occurs via a net hydrogen atom transfer (HAT) from 1* occurring either asynchronously or via a stepwise electron-proton transfer (ET-PT) process. Complex 2 is further demonstrated to reform dioxo 1 in the presence of chemical oxidants.

Ion pair receptors typically contain two separate binding sites, for the metal and the anion respectively. Here we report a less synthetically demanding approach, whereby we prepared a family of ion pair sensors based on a rhodamine fluorescent scaffold containing a tunable cation binding motif. When exposed to ion pairs, a competition for the metal ion is established between these ligands and anions. Structural and spectroscopic evidence showed that anions bind through weaker secondary interactions in the metal's outer coordination sphere and their presence influences the optical spectroscopic properties of the coordination complex in distinctive ways. The relationship between the binding site's metal affinity and its tunable properties, and the sensors' discriminatory power for anions was explained as a function of the metal ion's binding preferences. These effects were also exploited to discriminate cations and anions concurrently through multivariate data analysis methods.

Platinum-based compounds are actively used in clinical trials as anticancer agents. In this study, two novel platinum complexes, ( C 1 = [PtCl 2 ( N (SO 2 quin)dpa)], C 2 = [PtCl 2 ( N (SO 2 azobenz)dpa)]) containing quinoline and azobenzene appended dipicolylamine sulfonamide ligands were synthesized in good yield. The singlet attributable to methylene CH 2 protons of the ligands of C1 and C2 appears as two doublets in 1 H NMR spectra, which confirms the presence of magnetically nonequivalent protons upon coordination to platinum. Structural data of N (SO 2 quin)dpa (L1), N (SO 2 azobenz)dpa (L2) and PtCl 2 ( N (SO 2 quin)dpa) confirmed the formation of the desired compounds. Time-dependent density functional theory calculations suggested that the excitation of L1 show quin-unit-based π⟶π ∗ excitations (i.e., ligand-centered charge transfer, LC), while C1 shows the metal-ligand-to-ligand charge-transfer (MLLCT) character. L1 displays intense fluorescence from the 1 LC excited state, while C1 gives phosphorescence from the 3 LC state. Mammalian cell toxicity of ligands and complexes was assessed with NCI-H292 nonsmall-cell lung cancer cells. Further, C1 and C2 showed significantly low IC 50 values compared with N (SO 2 azobenz)dpa and PtCl 2 ( N (SO 2 quin)dpa). Fluorescence imaging data of both ligands and complexes revealed the potential fluorescence activity of these compounds for biological imaging. All four compounds are promising novel candidates that can be further investigated on their usage as potential anticancer agents and cancer cell imaging agents., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Charini Maladeniya et al.)

We describe a new synthetic reaction that generates all-carbon bis-quaternary centers at the opposing side of α-carbons in cyclohexanone with four different substituents in a controlled manner. Catalyzed by Cu(MeCN) 4 BF 4 salt, this chemistry is proposed to proceed via an intermediacy of unsymmetrical O -allyl oxyallyl cations, which undergo a sequence of regioselective nucleophilic addition with substituted indoles and diastereoselective Claisen rearrangement in a single synthetic operation. The stereochemical outcome of the products features the cis diastereorelationship between the two aryl groups at the α,α'-positions.

Boron dipyrromethene (BODIPY) dyes bearing a pyridyl moiety have been used as metal ion sensors, pH sensors, fluorescence probes, and as sensitizers for phototherapy. A comparative study of the properties of the three structural isomers of meso -pyridyl-BODIPYs, their 2,6-dichloro derivatives, and their corresponding methylated cationic pyridinium-BODIPYs was conducted using spectroscopic and electrochemical methods, X-ray analyses, and TD-DFT calculations. Among the neutral derivatives, the 3Py and 4Py isomers showed the highest relative fluorescence quantum yields in organic solvents, which were further enhanced 2-4-fold via the introduction of two chlorines at the 2,6-positions. Among the cationic derivatives, the 2catPy showed the highest relative fluorescence quantum yield in organic solvents, which was further enhanced by the use of a bulky counter anion (PF 6 - ). In water, the quantum yields were greatly reduced for all three isomers but were shown to be enhanced upon introduction of 2,6-dichloro groups. Our results indicate that 2,6-dichloro- meso -(2- and 3-pyridinium)-BODIPYs are the most promising for sensing applications. Furthermore, all pyridinium BODIPYs are highly water-soluble and display low cytotoxicity towards human HEp2 cells.

[1,4]Ditellurino[2,3- b :5,6- b ']di-pyrazine represents the first reported [1,4]chalcogena[2,3- b :5,6- b ']di-pyrazine containing a heavy chalcogens The asymmetric unit consists of three mol-ecules. In contrast to its sulfur analog, which is planar [Lynch et al. (1994 ▸) Cryst. Struct. Commun. 50 ,1470-1472], C 8 H 4 N 4 Te 2 is folded along the Te⋯Te axis to accommodate the larger chalcogenide atoms. The dihedral angle between the two Te 2 C 2 rings of the central ring is 57.9° (mean of three). C-Te bond lengths range from 2.1105 (16) Å to 2.1381 (17) Å, in good agreement with those predicted by their covalent radii. All Te atoms are involved in inter-molecular Te⋯N contacts, with distances in the range 2.894 (2) to 2.963 (2) Å. These result in a spiral supra-molecular assembly, forming helical columns., (© Franklin et al. 2022.)

The synthesis and reactivity of 3,8-dibromo-dodecafluoro-benzo-fused BOPHY 2 are reported, via S N Ar with O-, N- S- and C-nucleophiles, and in Pd(0)-catalyzed cross-coupling reactions (Suzuki and Stille). The resulting perfluoro-BOPHY derivatives were investigated for their reactivity in the presence of various nucleophiles. BOPHY 3 displays reversible color change and fluorescence quenching in the presence of bases (Et 3 N, DBU), whereas BOPHY 7 reacts preferentially at the α-pyrrolic positions, and BOPHY 8 undergoes regioselective fluorine substitution in the presence of thiols. The structural and electronic features of the fluorinated BOPHYs were studied by TD-DFT computations. In addition, their spectroscopic and cellular properties were investigated; BOPHY 10 shows the most red-shifted absorption/emission (λ max 659/699 nm) and 7 the highest fluorescence (Φ f =0.95), while all compounds studied showed low cytotoxicity toward human HEp2 cells and were efficiently internalized., (© 2022 Wiley-VCH GmbH.)

In the title compound, C 9 H 10 N 2 O 4 , the three substituents vary in the degree of lack of planarity with the central phenyl ring. The meth-oxy group is nearest to being coplanar, with a C-C-O-C torsion angle of 6.1 (5)°. The nitro group is less coplanar, with a 12.8 (5)° twist about the C-N bond and the acetamido group is considerably less coplanar with the central ring, having a 25.4 (5)° twist about the C-N bond to the ring. The NH group forms an intra-molecular N-H⋯O hydrogen bond to a nitro-group O atom., (© Hines III et al. 2022.)

In our ongoing effort to investigate active specialised metabolites from genus Glandularia, phytochemical studies on the ethanolic extract of Glandularia × hybrida (Groenl. & Rümpler) G.L. Nesom & Pruski leaves resulted in the isolation of three undescribed compounds, a dibenzylbutyrolactolic lignan and two echinocystic acid based triterpenoid saponins, in addition to two known compounds. Interestingly, this study reports isolation of chemo-systematically valuable specialised metabolites for the first time from the genus under investigation. Additionally, the isolated metabolites were evaluated for their iNOS inhibition and cytotoxic activities using a combination of in silico and in vitro studies. The pharmacokinetics properties (ADMET) of some of the isolated compounds were determined using pkCSM-pharmacokinetics server. Molecular docking analysis showed that saponin compound possesses higher negative score (-9.59 kcal/mol) than the lignan compound (-6.56 kcal/mol). The isolated compounds also showed iNOS inhibition activity with IC 50 values ranging between 6.6 and 49.7 μM and significant cytotoxic activity against a series of cell lines including SK-MEL, KB, BT-549, SK-OV-3, LLC-PK1 and VERO cells. Hence, this study reveals that specialised metabolites from G. hybrida plant are of significant anti-inflammatory and cytotoxicity potentials., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The title compound, C 8 H 8 N 2 O 4 , differs in its degree of planarity from the 3-nitro isomer and also in its hydrogen-bonding pattern. Its NH group forms an intra-molecular hydrogen bond to a nitro oxygen atom, and its OH group forms an inter-molecular hydrogen bond to an amide oxygen atom, generating [10] chains in the crystal., (© Hines III et al. 2022.)

Corticotropin-releasing factor (CRF) is a 41-amino-acid neuropeptide secreted from the hypothalamus and is the main regulator of the hypothalamus-pituitary-adrenocortical (HPA) axis. CRF is the master hormone which modulates physiological and behavioral responses to stress. Many disorders including anxiety, depression, addictive disorders and others are related to over activation of the CRF system. This suggests that new molecules which can interfere with CRF binding to its receptors may be potential candidates for neuropsychiatric drugs to treat stress-related disorders. Previously, three series of pyrimidine and fused pyrimidine CRF 1 receptor antagonists were synthesized by our group and specific binding assays, competitive binding studies and determination of the ability to antagonize the agonist-stimulated accumulation of cAMP (the second messenger for CRF receptors) were reported. In continuation of our efforts in this direction, in the current manuscript, we report the synthesis & biological evaluation of a new series of CRF 1 receptor antagonists. Seven compounds showed promising binding affinity with the best two compounds (compounds 6 & 43) displaying a superior binding affinity to all of our previous compounds. Compounds 6 & 43 have only 4 times and 2 times less binding affinity than the standard CRF antagonist antalarmin, respectively. Thus, our two best lead compounds (compound 6 & 43) can be considered potent CRF receptor antagonists with binding affinity of 41.0 & 19.2 nM versus 9.7 nM for antalarmin., (Copyright © 2021. Published by Elsevier B.V.)

Three novel small organic heterocyclic compounds: 2-(1,2-diphenyl)-1 H -benzimidazole-7- tert -butylpyrene (compound A ), 1,3-di(1,2-diphenyl)-1 H -benzimidazole-7- tert -butylpyrene (compound B ), and 1,3,6,8-tetra(1,2-diphenyl)-1 H -benzimidazolepyrene (compound C ) were synthesized and characterized for possible applications as blue OLED emitters. The specific molecular design targeted decreasing intermolecular aggregation and disrupting crystallinity in the solid-state, in order to reduce dye aggregation, and thus obtain efficient pure blue photo- and electroluminescence. Accordingly, the new compounds displayed reasonably high spectral purity in both solution- and solid-states with average CIE coordinates of (0.160 ± 0.005, 0.029 ± 0.009) in solution and (0.152 ± 0.007, 0.126 ± 0.005) in solid-state. These compounds showed a systematic decrease in degree of crystallinity and intermolecular aggregation due to increasing steric hindrance, as revealed using powder X-ray diffraction analysis and spectroscopic studies. An organic light-emitting diode (OLED) prototype fabricated using compound B as the non-doped emissive layer displayed an external quantum efficiency (EQE) of 0.35 (±0.04)% and luminance 100 (±6) cd m -2 at 5.5 V with an essentially pure blue electroluminescence corresponding to CIE coordinates of (0.1482, 0.1300). The highest EQE observed from this OLED prototype was 4.3 (±0.3)% at 3.5 V, and the highest luminance of 290 (±10) cd m -2 at 7.5 V. These values were found comparable to characteristics of the best pure blue OLED devices based on simple fluorescent small-molecule organic chromophores.

Large scale synthesis of cycloparaphenyleneacetylenes has been challenging due to low macrocyclization yields and harsh aromatization methods that often decompose strained alkynes. Herein, a cis -stilbene-based building block is subjected to alkyne metathesis macrocylization. The following sequence of alkene-selective bromination and dehydrobromination afforded a [8]cycloparaphenyleneacetylene derivative in high yield with good scalability. X-Ray crystal structure and computational analysis revealed a unique same-rim conformation for the eight methyl groups on the nanohoop.

A family of coumarin-enamine chemodosimeters is evaluated for their potential use as fluorescent molecular probes for multiple analytes [cadmium(II), cobalt(II), copper(II), iron(II), nickel(II), lead(II), and zinc(II)], as their chloride and acetate salts. These fluorophores displayed excellent optical spectroscopic modulation when exposed to ion pairs with different Lewis acidic and basic properties in dimethyl sulfoxide (DMSO). The chemodosimeters were designed to undergo excited-state intramolecular proton transfer (ESIPT), which leads to significant Stokes shifts (ca. 225 nm) and lower-energy fluorescence emission (ca. 575 nm). A more basic anion, e.g., acetate, inhibited the ESIPT mechanism by deprotonation of the enol, producing a binding pocket (N^O - chelate) that can coordinate to an appropriate metal ion. Coordination of the metal ions enhances the fluorescent intensity via the chelation-enhanced fluorescence emission mechanism. Subjecting the spectroscopic data to linear discriminant analysis provided insights into the source of these systems' markedly different behavior toward ion pairs, despite the subtle structural differences in the organic framework. These compounds are examples of versatile, low-molecular-weight, dual-channel fluorescent sensors for ion-pair recognition. This study paves the way for using these probes as practical components of a sensing array for different metal ions and their respective anions.

An efficient synthesis of rac -6-desmethyl-5β-hydroxy-d-secoartemisinin 2 , a tricyclic analog of R -(+)-artemisinin 1 , was accomplished and the racemate was resolved into the (+)- 2b and (-)- 2a enantiomers via their Mosher Ester diastereomers. Antimalarial activity resided with only the artemisinin-like enantiomer R -(-)- 2a . Several new compounds 9 - 16 , 19a , 19b , 22 and 29 were synthesized from rac - 2 but the C-5 secondary hydroxyl group was surprisingly unreactive. For example, the formation of carbamates and Mitsunobu reactions were unsuccessful. In order to assess the unusual reactivity of 2 , a single crystal X-ray crystallographic analysis revealed a close intramolecular hydrogen bond from the C-5 alcohol to the oxepane ether oxygen (O-11). All products were tested in vitro against the W-2 and D-6 strains of Plasmodium falciparum . Several of the analogs had moderate activity in comparison to the natural product 1 . Iron (II) bromide-promoted rearrangement of 2 gave, in 50% yield, the ring-contracted tetrahydrofuran 22 , while the 5-ketone 15 provided a monocyclic methyl ketone 29 (50%). Neither 22 nor 29 possessed in vitro antimalarial activity. These results have implications in regard to the antimalarial mechanism of action of artemisinin.

The intermediacy of metallacyclobutadienes as part of a [2 + 2]/retro-[2 + 2] cycloaddition-based mechanism is a well-established paradigm in alkyne metathesis with alternative species viewed as off-cycle decomposition products that interfere with efficient product formation. Recent work has shown that the exclusive intermediate isolated from a siloxide podand-supported molybdenum-based catalyst was not the expected metallacyclobutadiene but instead a dynamic metallatetrahedrane. Despite their paucity in the chemical literature, theoretical work has shown these species to be thermodynamically more stable as well as having modest barriers for cycloaddition. Consequentially, we report the synthesis of a library of group VI alkylidynes as well as the roles metal identity, ligand flexibility, secondary coordination sphere, and substrate identity all have on isolable intermediates. Furthermore, we report the disparities in catalyst competency as a function of ligand sterics and metal choice. Dispersion-corrected DFT calculations are used to shed light on the mechanism and role of ligand and metal on the intermediacy of metallacyclobutadiene and metallatetrahedrane as well as their implications to alkyne metathesis.

Three new Pt complexes, [PtCl 2 (N(SO 2 (2-nap))dpa)], [PtCl 2 (N(SO 2 (1-nap))dpa)] and [PtCl 2 (N(SO 2 pip)dpa)], containing a rare 8-membered ring were synthesized in good yield and high purity by utilizing the ligands N(SO 2 (2-nap))dpa, N(SO 2 (1-nap))dpa and N(SO 2 pip)dpa, which contain a dipicolylamine moiety. Structural studies of all three complexes confirmed that the ligands are bound in a bidentate mode via Pt-N (pyridyl) bonds forming a rare 8-membered ring. The intense fluorescence displayed by the ligands is quenched upon coordination to Pt. According to time dependent density functional theory (TDDFT) calculations, the key excitations of N(SO 2 (2-nap))dpa and [PtCl 2 (N(SO 2 (1-nap))dpa)] involve the 2-nap-ligand-centered π → π* excitations. While all six compounds have shown antiproliferative activity against human breast cancer cells (MCF-7), the N(SO 2 pip)dpa and N(SO 2 (2-nap))dpa ligands and [PtCl 2 ((NSO 2 pip)dpa)] complex have shown significantly high cytotoxicity, directing them to be further investigated as potential anti-cancer drug leads., Competing Interests: The authors declare no conflict of interest regarding the publication of this paper., (This journal is © The Royal Society of Chemistry.)

A copper(II) complex, (2,2'-bi-pyridine-κ 2 N , N ')[2-hy-droxy-2-(hy-droxy-methyl-κ O )propane-dioato-κ 2 O 1 , O 3 ]copper(II), [Cu(C 4 H 4 O 6 )(C 10 H 8 N 2 )], containing the unusual anionic chelating ligand 2-(hy-droxy-meth-yl)tartronate, has been synthesized. [Cu(bpy) 2 (NO 3 )](NO 3 ) was mixed with ascorbic acid and Dabco (1,4-di-aza-bicyclo-[2.2.2]octa-ne) in DMF (dimethylformamide) solution in the presence of air to produce the title compound. The structure consists of square-pyramidal complexes that are joined by Cu⋯O contacts [2.703 (2) Å] into centrosymmetric dimers. The C 4 H 4 O 6 2- ligand, which occupies three coordination sites at Cu, has previously been identified as an oxidation product of ascorbate ion., (© Gao et al. 2021.)

Organic compounds with electronic properties, such as a small band gap, are useful in areas ranging from organic field effect transistors to solar cells. Such organic compounds can possess conjugation and/or aromatic systems, with one example being tetraphenylcyclopentadienone and its derivatives. A trio of dramatically coloured tetraphenylcyclopentadienone derivatives with varied substituents on the aromatic rings in the 3- and 4-positions were prepared. Their identities were confirmed using the usual methods, for example 1 H nuclear magnetic resonance (NMR) spectroscopy, and their purity quantified using elemental analysis. The X-ray crystal structure of compound 2 was determined. Its notable structural features involved the cyclopentadienone core with its distinct C-C and C=C bond lengths and its overall nonplanarity, both of which served to mitigate its antiaromatic nature. Chloroform solutions of compounds 2-4 exhibited absorption spectra with three absorption bands at approximately 250, 350, and 500 nm that were assigned to (π)→(π*) transitions. Computational chemistry methods assisted in assigning the observed transitions to a specific molecular orbital combination in the structures of 2-4. Emission in the red end of the visible spectrum (550-625 nm) was observed from chloroform solutions of all three of the prepared compounds., (© 2020 John Wiley & Sons, Ltd.)

Bioassay-guided fractionation of the ethyl acetate extract of Amyris elemifera leaves was carried out to identify phytotoxic and antifungal constituents. A novel phytotoxic furanocoumarin 8-(3-methylbut-2-enyloxy)-marmesin acetate ( 1 ) and its deacyl analog 8-(3-methylbut-2-enyloxy)-marmesin ( 2 ) were isolated. The X-ray crystal structure determination is reported for the first time for 1 . Both 1 and 2 have the S configuration at C-2' based on X-ray crystallographic data. Both these compounds inhibited the growth of the dicot Lactuca sativa (lettuce) and the monocot Agrostis stolonifera with a more pronounced inhibitory effect on the monocots at 330 μM by 1 . In Lemna paucicostata Hegelm phytotoxicity bioassay, the IC 50 value for 1 was 26 μM, whereas 2 had an IC 50 value of 102 μM. Compounds 1 and 2 were weakly antifungal against Colletotrichum fragariae Brooks in TLC bioautography., Competing Interests: The authors declare no competing financial interest., (© 2020 The Authors. Published by American Chemical Society.)