Peroxides in metal complex catalysis

Synergism of primary and secondary interactions in a crystalline hydrogen peroxide complex with tin

Despite the significance of H2O2-metal adducts in catalysis, materials science and biotechnology, the nature of the interactions between H2O2 and metal cations remains elusive and debatable. This is primarily due to the extremely weak coordinating ability of H2O2, which poses challenges in characterizing and understanding the specific nature of these interactions. Herein, we present an approach to obtain H2O2-metal complexes that employs neat H2O2 as both solvent and ligand. SnCl4 effectively binds H2O2, forming a SnCl4(H2O2)2 complex, as confirmed by 119Sn and 17O NMR spectroscopy. Crystalline adducts, SnCl4(H2O2)2·H2O2·18-crown-6 and 2[SnCl4(H2O2)(H2O)]·18-crown-6, are isolated and characterized by X-ray diffraction, providing the complete characterization of the hydrogen bonding of H2O2 ligands including geometric parameters and energy values. DFT analysis reveals the synergy between a coordinative bond of H2O2 with metal cation and its hydrogen bonding with a second coordination sphere. This synergism of primary and secondary interactions might be a key to understanding H2O2 reactivity in biological systems.

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

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

Electrochemical Generation of Peroxy Radicals and Subsequent Peroxidation of 1,3-Dicarbonyls in an Undivided Cell

The generation of peroxy radicals from hydroperoxides with subsequent selective peroxidation of 1,3-dicarbonyls in an undivided electrochemical cell under constant current conditions is reported. The method provides a variety of peroxy-containing barbituric acids and 4-hydroxy-2(5H)-furanones with yields of up to 74%. Only the combination of anodic and cathodic processes provides efficient peroxidation by generating a set of alkoxy and peroxy radicals. NaNO3 acts as both an electrolyte and a redox mediator of radical reactions.

Crystal structure and Hirshfeld surface analysis of dieth-yl (3aS,3a1R,4S,5S,6R,6aS,7R,9aS)-3a1,5,6,6a-tetra-hydro-1H,3H,4H,7H-3a,6:7,9a-di-epoxy-benzo[de]isochromene-4,5-di-carboxyl-ate

In the title compound, C18H22O7, two hexane rings and an oxane ring are fused together. The two hexane rings tend toward a distorted boat conformation, while the tetra-hydro-furan and di-hydro-furan rings adopt envelope conformations. The oxane ring is puckered. The crystal structure features C-H⋯O hydrogen bonds, which link the mol-ecules into a three-dimensional network. According to a Hirshfeld surface study, H⋯H (60.3%) and O⋯H/H⋯O (35.3%) inter-actions are the most significant contributors to the crystal packing.

Crystal structure and Hirshfeld surface analysis of 3-benzyl-2-[bis(1H-pyrrol-2-yl)methyl]thiophene

In the title compound, C20H18N2S, the asymmetric unit comprises two similar mol-ecules (A and B). In mol-ecule A, the central thio-phene ring makes dihedral angles of 89.96 (12) and 57.39 (13)° with the 1H-pyrrole rings, which are bent at 83.22 (14)° relative to each other, and makes an angle of 85.98 (11)° with the phenyl ring. In mol-ecule B, the corresponding dihedral angles are 89.49 (13), 54.64 (12)°, 83.62 (14)° and 85.67 (11)°, respectively. In the crystal, mol-ecular pairs are bonded to each other by N-H⋯N inter-actions. N-H⋯π and C-H⋯π inter-actions further connect the mol-ecules, forming a three-dimensional network. A Hirshfeld surface analysis indicates that H⋯H (57.1% for mol-ecule A; 57.3% for mol-ecule B), C⋯H/H⋯C (30.7% for mol-ecules A and B) and S⋯H/H⋯S (6.2% for mol-ecule A; 6.4% for mol-ecule B) inter-actions are the most important contributors to the crystal packing.

Synthesis, crystal structure and Hirshfeld surface analysis of 5-[2-(di-cyano-methyl-idene)hydrazin-1-yl]-2,4,6-tri-iodo-isophthalic acid ethanol monosolvate

The title compound, C11H3I3N4O4·C2H6O, crystallizes in the triclinic P space group with one independent mol-ecule and one ethanol solvent mol-ecule in the asymmetric unit. The benzene ring and the methyl-carbonohydrazonoyl dicyanide group of the main mol-ecule makes a dihedral angle of 57.91 (16)°. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link pairs of mol-ecules, forming dimers with R 2 2(14) motifs. These dimers are connected by O-H⋯O hydrogen bonds into chains along the a-axis direction, forming R 2 2(16) ring motifs. Further O-H⋯O inter-actions involving the ethanol solvent mol-ecule connect the chains into a three-dimensional network. In addition, C-I⋯π inter-actions are observed. The inter-molecular inter-actions in the crystal structure were qu-anti-fied and analysed using Hirshfeld surface analysis.

Endogenous Photosensitizers in Human Skin

Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.

Crystal structures and Hirshfeld surface analyses of N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol tribromide (1/1), N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-bromido-iodate (1/1) and N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-chlorido-iodate (1/1)

In the title compounds, N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol tribromide (1/1), C4H9NO·C4H10NO+·Br3 - or [(C4H9NO)·(C4H10NO)](Br3), (I), N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-bromido-iodate (1/1), C4H9NO·C4H10NO+·Br2I- or [(C4H9NO)·(C4H10NO)](Br2I), (II), and N,N-di-methyl-acetamide-1-(dimethyl-λ4-aza-nyl-idene)ethan-1-ol di-chlorido-iodate (1/1), C4H9NO·C4H10NO+·Cl2I- or [(C4H9NO)·(C4H10NO)]·(Cl2I), (III), all the anions are almost linear in geometry and all the cations, except for the methyl H atoms, are essentially planar. In the crystal structure of (I), the cations are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. These dimers also exhibit O-H⋯O hydrogen bonding. Dimerized cation pairs and anions are arranged in columns along the a axis. In the crystal of (II), the cations are linked by pairs of O-H⋯O and C-H⋯O hydrogen bonds, forming an R 4 4(14) ring motif. These groups of cations and the anions form individual columns along the a axis and jointly reside in planes roughly parallel to (011). In the crystal of (III), cations and anions also form columns parallel to the a axis, resulting in layers parallel to the (020) plane. Furthermore, the crystal structures of (I), (II) and (III) are consolidated by strong halogen (Br and/or I and/or Cl)⋯H and weak van der Waals inter-actions. In addition to the structural evaluation, a Hirshfeld surface analysis was carried out.

Crystal structure and Hirshfeld surface analysis of bis-{(Z)-N'-[(E)-(furan-2-yl)methyl-idene]carbamo-hydrazono-thio-ato}nickel(II) methanol disolvate

In the title complex, [Ni(C6H6N3OS)2]·2CH3OH, the NiII atom is coordinated by the S and N atoms of two N'-[(Z)-(furan-2-yl)methyl-idene]carbamohydrazono-thioic acid ligands in a distorted square-planar geometry. The two mutual ligands bound to NiII are also connected by C-H⋯S inter-actions, while the H atoms of the NH2 group of the ligands form R 4 4(8) motifs with the O atoms of the solvent ethyl alcohol mol-ecules. At the same time, the OH groups of the solvent ethyl alcohol mol-ecules form parallel layers to the (011) plane by the O-H⋯N inter-actions with the ligand N atom that is not bonded to the NiII atom.. The layers are connected by van der Waals inter-actions. A Hirshfeld surface analysis indicates that the most important contacts are H⋯H (37.7%), C⋯H/H⋯C (14.6%), O⋯H/H⋯O (11.5%) and S⋯H/H⋯S (10.6%).

Synthesis and crystal structure of catena-poly[[[aqua-{2-[(E)-(1-cyano-2-imino-2-meth-oxy-ethyl-idene)hydrazin-yl]benzene-sulfonato}-sodium]-di-μ-aqua] dihydrate]

In the polymeric title compound, {[Na(C₁₀H₉N₄O₄S)(H₂O)₃]·2H₂O} _n , sixfold coordinated Na⁺ cations are linked into a chain parallel to [010] by sharing common water mol-ecules. Next to the four bridging water mol-ecules, each Na⁺ cation of the chain is bonded to the O atom of a terminal water mol-ecule and an O atom of the SO₃ ^- group of the sulfonate anion. Classical O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds and additional π-π inter-actions connect these chains into a three-dimensional network.

Crystal structure and Hirshfeld surface analysis of N-[2-(5-methyl-furan-2-yl)phen-yl]-3-nitro-N-[(3-nitro-phen-yl)sulfon-yl]benzene-sulfonamide

In the title compound, C₂₃H₁₇N₃O₉S₂, C-H⋯O hydrogen bonds link adjacent mol-ecules in a three-dimensional network, while π-π stacking inter-actions, with centroid-centroid distances of 3.8745 (9) Å, between the furan and an arene ring of one of the two (3-nitro-phen-yl)sulfonyl groups, result in chains parallel to the a axis. The Hirshfeld surface analysis indicates that O⋯H/H⋯O (40.1%), H⋯H (27.5%) and C⋯H/H⋯C (12.4%) inter-actions are the most significant contributors to the crystal packing.

Enantioselective Radical-Type 1,2-Alkoxy-Phosphinoylation to Styrenes Catalyzed by Chiral Vanadyl Complexes

A series of vanadyl complexes bearing 3-t-butyl-5-bromo, 3-aryl-5-bromo, 3,5-dihalo-, and benzo-fused N-salicylidene-tert-leucinates was examined as catalysts for 1,2-alkoxy-phosphinoylation of 4-, 3-, 3,4-, and 3,5-substituted styrene derivatives (including Me/t-Bu, Ph, OR, Cl/Br, OAc, NO₂ , C(O)Me, CO₂ Me, CN, and benzo-fused) with HP(O)Ph₂ in the presence of t-BuOOH (TBHP) in a given alcohol or cosolvent with MeOH. The best scenario involved the use of 5 mol % 3-(2,5-dimethylphenyl)-5-Br (i.e., 3-DMP-5-Br) catalyst at 0 °C in MeOH. The desired catalytic cross coupling reactions proceeded smoothly with enantioselectivities of up to 95 % ee of (R)-configuration as confirmed by X-ray crystallographic analysis of several recrystallized products. The origin of enantiocontrol and homolytic substitution of the benzylic intermediates by vanadyl-bound methoxide and radical type catalytic mechanism were proposed.

Peroxide-Selective Reduction of O2 at Redox-Inactive Rare-Earth(III) Triflates Generates an Ambiphilic Peroxide

Metal peroxides are key species involved in a range of critical biological and synthetic processes. Rare-earth (group III and the lanthanides; Sc, Y, La-Lu) peroxides have been implicated as reactive intermediates in catalysis; however, reactivity studies of isolated, structurally characterized rare-earth peroxides have been limited. Herein, we report the peroxide-selective (93-99% O₂^2-) reduction of dioxygen (O₂) at redox-inactive rare-earth triflates in methanol using a mild metallocene reductant, decamethylferrocene (Fc*). The first molecular praseodymium peroxide ([Pr^III₂(O₂^2-)(18C6)₂(EG)₂][OTf]₄; 18C6 = 18-crown-6, EG = ethylene glycol, ^-OTf = ^-O₃SCF₃; 2-Pr) was isolated and characterized by single-crystal X-ray diffraction, Raman spectroscopy, and NMR spectroscopy. 2-Pr displays high thermal stability (120 °C, 50 mTorr), is protonated by mild organic acids [pK_a1(MeOH) = 5.09 ± 0.23], and engages in electrophilic (e.g., oxygen atom transfer) and nucleophilic (e.g., phosphate-ester cleavage) reactivity. Our mechanistic studies reveal that the rate of oxygen reduction is dictated by metal-ion accessibility, rather than Lewis acidity, and suggest new opportunities for differentiated reactivity of redox-inactive metal ions by leveraging weak metal-ligand binding events preceding electron transfer.

Crystal structure and Hirshfeld surface analysis of 2-(4-amino-6-phenyl-1,2,5,6-tetra-hydro-1,3,5-triazin-2-yl-idene)malono-nitrile di-methyl-formamide hemisolvate

The title compound, 2C₁₂H₁₀N₆·C₃H₇NO, crystallizes as a racemate in the monoclinic P2₁/c space group with two independent mol-ecules (I and II) and one di-methyl-formamide solvent mol-ecule in the asymmetric unit. Both mol-ecules (I and II) have chiral centers at the carbon atoms where the triazine rings of mol-ecules I and II are attached to the phenyl ring. In the crystal, mol-ecules I and II are linked by inter-molecular N-H⋯N, N-H⋯O and C-H⋯N hydrogen bonds through the solvent di-methyl-formamide mol-ecule into layers parallel to (001). In addition, C-H⋯π inter-actions also connect adjacent mol-ecules into layers parallel to (001). The stability of the mol-ecular packing is ensured by van der Waals inter-actions between the layers. The Hirshfeld surface analysis indicates that N⋯H/H⋯N (38.3% for I; 35.0% for II), H⋯H (28.2% for I; 27.0% for II) and C⋯H/H⋯C (23.4% for I; 26.3% for II) inter-actions are the most significant contributors to the crystal packing.

Crystal structure and Hirshfeld surface analysis of a new polymorph of (E)-2-(4-bromophenyl)-1-[2,2-dibromo-1-(3-nitrophenyl)ethenyl]diazene

The a new polymorph of the title compound is reported in which the C—H⋯O hydrogen bonds and π-π stacking inter­actions link mol­ecules into the layers in the crystal.

A new polymorph of the title compound, C₁₄H₈Br₃N₃O₂, (form-2) was obtained in the same manner as the previously reported form-1 [Akkurt et al. (2022 ▸). Acta Cryst. E78, 732–736]. The structure of the new polymorph is stabilized by a C—H⋯O hydrogen bond that links mol­ecules into chains. These chains are linked by face-to-face π–π stacking inter­actions, resulting in a layered structure. Short inter-mol­ecular Br⋯O contacts and van der Waals inter­actions between the layers aid in the cohesion of the crystal packing. In the previously reported form-1, C—H⋯Br inter­actions connect mol­ecules into zigzag chains, which are linked by C—Br⋯π inter­actions into layers, whereas the van der Waals inter­actions between the layers stabilize the crystal packing of form-2. Hirshfeld mol­ecular surface analysis was used to compare the inter­molecular inter­actions of the polymorphs.

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

The mol-ecule of the title compound, C₁₄H₈Br₃N₃O₂, consists of three almost planar groups: the central di-bromo-ethenyldiazene fragment and two attached aromatic rings. The mean planes of these rings form dihedral angles with the plane of the central fragment of 26.35 (15) and 72.57 (14)° for bromine- and nitro-substituted rings, respectively. In the crystal, C-H⋯Br inter-actions connect mol-ecules, generating zigzag C(8) chains along the [100] direction. These chains are linked by C-Br⋯π inter-actions into layers parallel to (001). van der Waals inter-actions between the layers aid in the cohesion of the crystal packing. The most substantial contributions to crystal packing, according to a Hirshfeld surface analysis, are from Br⋯H/H⋯Br (20.9%), C⋯H/H⋯C (15.2%), O⋯H/H⋯O (12.6%) and H⋯H (11.7%) contacts.

Novel Copper(II) Complexes with Dipinodiazafluorene Ligands: Synthesis, Structure, Magnetic and Catalytic Properties

The reactions of CuX₂ (X = Cl, Br) with dipinodiazafluorenes yielded four new complexes [CuX₂L₁]₂ (X = Cl (1), Br (2), L₁ = (1R,3R,8R,10R)-2,2,9,9-Tetramethyl-3,4,7,8,9,10-hexahydro-1H-1,3:8,10-dimethanocyclopenta [1,2-b:5,4-b’]diquinolin-12(2H)-one) and [(CuX₂)₂L₂]n (X = Cl (3), Br (4), L₂ = (1R,3R,8R,10R,1’R,3’R,8’R,10’R)-2,2,2’,2’,9,9,9’,9’-Octamethyl-1,1’,2,2’,3,3’,4,4’,7,7’,8,8’,9,9’,10,10’-hexadecahydro-1,3:1’,3’:8,10:8’,10’-tetramethano-12,12’-bi(cyclopenta [1,2-b:5,4-b’]diquinolinylidene). The complexes were characterized by IR and EPR spectroscopy, HR-ESI-MS and elemental analysis. The crystal structures of compounds 1, 2 and 4 were determined by X-ray diffraction (XRD) analysis. Complexes 1–2 have a monomeric structure, while complex 4 has a polymeric structure due to additional coordinating N,N sites in L₂. All complexes contain a binuclear fragment {Cu₂(μ-X)_2×2} (X = Cl, Br) in their structures. Each copper atom has a distorted square-pyramidal coordination environment formed by two nitrogen atoms and three halogen atoms. The Cu-N_ax distance is elongated compared to Cu-N_eq. The EPR spectra of compounds 1–4 in CH₃CN confirm their paramagnetic nature due to the d⁹ electronic configuration of the copper(II) ion. The magnetic properties of all compounds were studied by the method of static magnetic susceptibility. For complexes 1 and 2, the effective magnetic moments are µ_eff ≈ 1.87 and 1.83 µ_B (per each Cu²⁺ ion), respectively, in the temperature range 50–300 K, which are close to the theoretical spin value (1.73 µ_B). Ferromagnetic exchange interactions between Cu(II) ions inside {Cu₂(μ-X)₂X₂} (X = Cl, Br) dimers (J/k_B ≈ 25 and 31 K for 1 and 2, respectively) or between dimers (θ′ ≈ 0.30 and 0.47 K for 1 and 2, respectively) were found at low temperatures. For compounds 3 and 4, the magnetic susceptibility is well described by the Curie–Weiss law in the temperature range 1.77–300 K with µ_eff ≈ 1.72 and 1.70 µ_B for 3 and 4, respectively, and weak antiferromagnetic interactions (θ ≈ −0.4 K for 3 and −0.65 K for 4). Complexes 1–4 exhibit high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The maximum yield of cyclohexane oxidation products reached 50% (complex 3). Based on the data on the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play a decisive role in the oxidation reaction. The initial products in reactions with alkanes are alkyl hydroperoxides.

Scalable Electrochemical Aerobic Oxygenation of Indoles to Isatins without Electron Transfer Mediators by Merging with an Oxygen Reduction Reaction

An approach to electrochemical oxygenation of indoles leading to isatins was developed by merging with a complementary cathode oxygen reduction reaction. The features of this green protocol include the use of molecular oxygen as the sole oxidant, it being free of an electron transfer mediator, and gram-scale preparation. Mechanistic studies suggested a radical process, and the two oxygen atoms in the isatins were both most likely from molecular oxygen. A detailed mechanism of the reaction utilizing density functional theory calculations was elucidated.

Crystal structure and Hirshfeld surface analysis of (E)-1-[2,2-dibromo-1-(4-nitrophenyl)ethenyl]-2-(4-fluorophenyl)diazene

In the title compound, C14H8Br2FN3O2, the 4-fluorophenyl ring and the nitro-substituted phenyl ring form a dihedral angle of 64.37 (10)°. Molecules in the crystal are connected by C—H...O and C—H...F hydrogen bonds into layers parallel to (011). The crystal packing is consolidated by C—Br...π and C—F...π interactions, as well as by π–π stacking interactions. According to a Hirshfeld surface analysis of the crystal structure, the most significant contributions to the crystal packing are from O...H/H...O (15.0%), H...H (14.3%), Br...H/H...Br (14.2%), C...H/H...C (10.1%), F...H/H...F (7.9%), Br...Br (7.2%) and Br...C/C...Br (5.8%) contacts.

Crystal structure and Hirshfeld surface analysis of 2,2,2-tri-fluoro-1-(7-methyl-imidazo[1,2-a]pyridin-3-yl)ethan-1-one

The bicyclic imidazo[1,2-a]pyridine core in the mol-ecule of the title compound, C10H7F3N2O, is planar within 0.004 (1) Å. In the crystal, the mol-ecules are linked by pairs of C-H⋯N and C-H⋯O hydrogen bonds, forming strips. These strips are connected by the F⋯F contacts into layers, which are further joined by π-π stacking inter-actions. The Hirshfeld surface analysis and fingerprint plots reveal that mol-ecular packing is governed by F⋯H/H⋯F (31.6%), H⋯H (16.8%), C⋯H/H⋯C (13.8%) and O⋯H/H⋯O (8.5%) contacts.

Water-soluble Al(iii), Fe(iii) and Cu(ii) formazanates: synthesis, structure, and applications in alkane and alcohol oxidations

The synthesis, structure and catalytic performance of water-soluble Al(iii), Fe(iii) and Cu(ii) formazanates in the oxidation of cyclohexane and cyclohexanol to the coresponding organic products are reported.

Crystal structure and Hirshfeld surface analysis of 3-[2-(3,5-di-methyl-phen-yl)hydrazinyl-idene]benzo-furan-2(3H)-one

In the title compound, C16H14N2O2, the 2,3-di-hydro-1-benzo-furan ring system is essentially planar and makes a dihedral angle of 3.69 (7)° with the di-methyl-phenyl ring. The mol-ecular conformation is stabilized by an intra-molecular N-H⋯O hydrogen bond with an S(6) ring motif. In the crystal, mol-ecules are connected by C-H⋯π and π-π stacking inter-actions, forming a layer lying parallel to the (11) plane. One methyl group is disordered over two orientations, with occupancies of 0.67 (4) and 0.33 (4). Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (51.2%), O⋯H/H⋯O (17.9%), C⋯H/H⋯C (15.2%) and C⋯C (8.1%) contacts.

Crystal structure and Hirshfeld surface analysis of (3aSR,6RS,6aSR,7RS,11bSR,11cRS)-2,2-dibenzyl-2,3,6a,11c-tetra-hydro-1H,6H,7H-3a,6:7,11b-di-epoxy-dibenzo[de,h]isoquinolin-2-ium tri-fluoro-methane-sulfonate

In the cation of the title salt, C30H28NO2 +·CF3O3S-, the four tetra-hydro-furan rings adopt envelope conformations. In the crystal, pairs of cations are linked by dimeric C-H⋯O hydrogen bonds, forming two R 2 2(6) ring motifs parallel to the (001) plane. The cations and anions are connected by further C-H⋯O hydrogen bonds, forming a three-dimensional network structure. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (47.6%), C⋯H/H⋯C (20.6%), O⋯H/H⋯O (18.0%) and F⋯H/H⋯F (9.9%) inter-actions.

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

In the title compound, C14H7Cl4FN2, the dihedral angle between the 4-fluoro-phenyl ring and the 2,4-di-chloro-phenyl ring is 46.03 (19)°. In the crystal, the mol-ecules are linked by C-H⋯N inter-actions along the a-axis direction, forming a C(6) chain. The mol-ecules are further connected by C-Cl⋯π inter-actions and face-to-face π-π stacking inter-actions, forming ribbons along the a-axis direction. Hirshfeld surface analysis indicates that the greatest contributions to the crystal packing are from Cl⋯H/H⋯Cl (35.1%), H⋯H (10.6%), C⋯C (9.7%), Cl⋯Cl (9.4%) and C⋯H/H⋯C (9.2%) inter-actions.

Crystal structure and Hirshfeld surface analysis of (E)-1-[2,2-di-chloro-1-(4-methyl-phen-yl)ethen-yl]-2-(4-meth-oxy-phen-yl)diazene

The asymmetric unit of the title compound, C16H14Cl2N2O, comprises two similar mol-ecules, A and B, in which the dihedral angles between the two aromatic rings are 70.1 (3) and 73.2 (2)°, respectively. The crystal structure features short C-H⋯Cl and C-H⋯O contacts and C-H⋯π and van der Waals inter-actions. The title compound was refined as a two-component non-merohedral twin, BASF 0.1076 (5). The Hirshfeld surface analysis and two-dimensional fingerprint plots show that H⋯H (38.2% for mol-ecule A; 36.0% for mol-ecule B), Cl⋯H/H⋯Cl (24.6% for mol-ecule A; 26.7% for mol-ecule B) and C⋯H/H⋯C (20.0% for mol-ecule A; 20.2% for mol-ecule B) inter-actions are the most important contributors to the crystal packing.

Crystal structure and Hirshfeld surface analysis of (3Z)-7-meth-oxy-3-(2-phenyl-hydrazinyl-idene)-1-benzo-furan-2(3H)-one

In the title compound, C15H12N2O3, pairs of mol-ecules are linked into dimers by N-H⋯O hydrogen bonds, forming an R 2 2(12) ring motif, with the dimers stacked along the a axis. These dimers are connected through π-π stacking inter-actions between the centroids of the benzene and furan rings of their 2,3-di-hydro-1-benzo-furan ring systems. Furthermore, there exists a C-H⋯π inter-action that consolidates the crystal packing. A Hirshfeld surface analysis indicates that the most important contacts are H⋯H (40.7%), O⋯H/H⋯O (24.7%), C⋯H/H⋯C (16.1%) and C⋯C (8.8%).

Crystal structure and Hirshfeld surface analysis of (3aR,4S,7S,7aS)-4,5,6,7,8,8-hexa-chloro-2-{6-[(3aR,4R,7R,7aS)-4,5,6,7,8,8-hexa-chloro-1,3-dioxo-1,3,3a,4,7,7a-hexa-hydro-2H-4,7-methano-isoindol-2-yl]hex-yl}-3a,4,7,7a-tetra-hydro-1H-4,7-methano-iso-indole-1,3(2H)-dione

The mol-ecule of the title compound, C24H16Cl12N2O4, is generated by a crystallographic inversion centre at the midpoint of the central C-C bond. A kink in the mol-ecule is defined by a torsion angle of -169.86 (15)° about this central bond of the alkyl bridge. The pyrrolidine ring is essentially planar [max. deviation = 0.014 (1) Å]. The cyclo-hexane ring has a boat conformation, while both cyclo-pentane rings adopt an envelope conformation. In the crystal structure, mol-ecules are linked by inter-molecular C-H⋯O, C-H⋯Cl and C-Cl⋯π inter-actions, and short inter-molecular Cl⋯O and Cl⋯Cl contacts, forming a three-dimensional network.

Crystal structure and Hirshfeld surface analysis of (2Z)-N,N-dimethyl-2-(penta-fluoro-phen-yl)-2-(2-phenyl-hydrazin-1-yl-idene)acetamide

In the title compound, C16H12F5N3O, the dihedral angle between the aromatic rings is 31.84 (8)°. In the crystal, the mol-ecules are linked into dimers possessing crystallographic twofold symmetry by pairwise N-H⋯O hydrogen bonds and weak C-H⋯O hydrogen bonds and aromatic π-π stacking inter-actions link the dimers into a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from F⋯H/H⋯F (41.1%), H⋯H (21.8%), C⋯H/H⋯C (9.7%) C⋯C (7.1%) and O⋯H/H⋯O (7.1%) contacts. 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.

Crystal structure and Hirshfeld surface analysis of 1,3-bis-{2,2-di-chloro-1-[(E)-phenyl-diazen-yl]ethen-yl}benzene

In the mol-ecule of the title compound, C22H14Cl4N4, the central benzene ring makes dihedral angles of 77.03 (9) and 81.42 (9)° with the two approximately planar 2,2-di-chloro-1-[(E)-phenyl-diazen-yl]vinyl groups. In the crystal, mol-ecules are linked by C-H⋯π, C-Cl⋯π, Cl⋯Cl and Cl⋯H inter-actions, forming a three-dimensional network. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (30.4%), C⋯H/H⋯C (20.4%), Cl⋯H/H⋯Cl (19.4%), Cl⋯Cl (7.8%) and Cl⋯C/C⋯Cl (7.3%) inter-actions.

Crystal structure and Hirshfeld surface analysis of dimethyl 5-[2-(2,4,6-trioxo-1,3-diazinan-5-yl-idene)hydrazin-1-yl]benzene-1,3-di-carboxyl-ate 0.224-hydrate

In the crystal, the whole mol-ecule of the title compound, C14H12N4O7·0.224H2O, is nearly planar with a maximum deviation from the least-squares plane of 0.352 (1) Å. The mol-ecular conformation is stabilized by an intra-molecular N-H⋯O hydrogen bond, generating an S(6) ring motif. In the crystal, mol-ecules are linked by centrosymmetric pairs of N-H⋯O hydrogen bonds, forming ribbons along the c-axis direction. These ribbons connected by van der Waals contacts, forming sheets parallel to the ac plane. There are also inter-molecular van der Waals contacts and and C-H⋯π inter-actions between the sheets. A Hirshfeld surface analysis indicates that the most prevalent inter-actions are O⋯H/H⋯O (41.2%), H⋯H (19.2%), C⋯H/H⋯C (12.2%) and C⋯O/ O⋯C (8.4%).

Crystal structure and Hirshfeld surface analysis of 5,7-diphenyl-1,2,3,5,6,7-hexa-hydro-imidazo[1,2-a]pyridine-6,6,8-tricarbo-nitrile methanol mono-solvate

In the title compound, C22H17N5·CH4O, the imidazolidine ring of the 1,2,3,5,6,7-hexa-hydro-imidazo[1,2-a]pyridine ring system is a twisted envelope, while the 1,2,3,4-tetra-hydro-pyridine ring adopts a twisted boat conformation. In the crystal, pairs of mol-ecules are linked by O-H⋯N and N-H⋯O hydrogen bonds via two methanol mol-ecules, forming a centrosymmetric R 4 4(16) ring motif. These motifs are connected to each other by C-H⋯N hydrogen bonds and form columns along the a axis. The columns form a stable mol-ecular packing, being connected to each other by van der Waals inter-actions. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing are from H⋯H (43.8%), N⋯H/H⋯N (31.7%) and C⋯H/H⋯C (18.4%) contacts.

Molecular Cage Promoted Aerobic Oxidation or Photo-Induced Rearrangement of Spiroepoxy Naphthalenone

Herein, we report a Pd4L2-type molecular cage (1) and catalyzed reactions of spiroepoxy naphthalenone (2) in water, where selective formation of 2-(hydroxymethyl)naphthalene-1,4-dione (3) via aerobic oxidation, or 1-hydroxy-2-naphthaldehyde (4) via photo-induced rearrangement under N2 have been accomplished. Encapsulation of four molecules of guest 2 within cage 1, i.e., (2)4⊂1, has been confirmed by NMR, and a final host-guest complex of 3⊂1 has also been determined by single crystal X-Ray diffraction study. While the photo-induced ring-opening isomerization from 2 to 4 are known, appearance of charge-transfer absorption on the host-guest complex of (2)4⊂1 allows low-power blue LEDs irradiation to promote this process.