Structures of Polyacetoxybriaranes Extracted from the Sea Whip Octocoral Junceella fragilis.

In the present study, an algae-containing octocoral, Junceella fragilis, was subjected to chemical screening. The analysis resulted in the extraction of six polyacetoxybriaranes: a new compound, identified as fragilide Z (1), alongside previously identified analogs, which included 12-epi-fragilide G (2), fragilide P (3), junceellolide D (4), junceellonoid A (5), and juncin ZI (6). The structures of compounds 2-6 were investigated through single-crystal X-ray diffraction analysis, whereas that of 1 was examined through two-dimensional nuclear magnetic resonance analysis.

Synthesis of polysubstituted tetrahydrofurans visible light-induced De Mayo acetalization of benzoylacetones.

A visible light photocatalytic cascade reaction was developed, involving sequential self-[2+2] photodimerization of benzoylacetones, De Mayo reaction, acetalization, and alkoxylation, yielding tetrahydrofurans with high stereoselectivity, three stereogenic centers, and two quaternary carbons, under mild conditions with a cycloaddition-rearrangement strategy. Given the significance of photoreaction and rearrangement in organic chemistry, this method provides a valuable approach for the synthesis of tetrahydrofurans.

Supramolecular Assembly, Solvent-Induced, and Mechanochromic Luminescence of Au(I) Quinoline-8-thiolates.

AuCl(PMe) and AuCl(PEt) were used to react with quinoline-8-thiolate (8-QNS) to give three Au(I) complexes, i.e., [8-QNS(AuPMe)]ClO (), [(8-QNS)Ag(AuPMe)]ClO (), and [8-QNS(AuPEt)]ClO (), which have been structurally determined by X-ray diffraction to show various intra- and intermolecular metal···metal contacts (i.

An exceptional water stable terbium-based metal-organic framework for selective detection of pesticides.

A terbium-based metal-organic framework (MOF) with exceptional water stability for highly selective detection of pesticide thiamethoxam (TMX) in aqueous solution is reported. To date, most reported lanthanide metal-organic frameworks (Ln-MOFs) still exhibit poor water stability, which may limit their practical applications in bio-sensing and detecting pollutants in environmental water samples. In this work, a Tb-MOF [Tb(BDC)(DEF)·0.

Structural Diversity and Dimensionality of Three Cu(II)-dpds-CO Coordination Polymers Controlled by the Coordination Sphere of Cu(II) Centers and the Coordination Modes of CO (dpds = 4,4'-Dipyridyldisulfide).

Three supramolecular architectures, [Cu(dpds)(CO)(HO)]·3HO (), [Cu(dpds)(CO)]·3HO (), and [Cu(dpds)(CO)]·9HO·CHOH () (dpds = 4,4'-dipyridyldisulfide and CO (croconate) = dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione), have been synthesized and structurally characterized. Compound contains two crystallographically independent Cu(II) ions, which are both distorted octahedral geometry with elongation along the croconate- and HO-bound axial positions and bonded with two N atoms of two dpds, two O atoms of one CO , and two HO molecules. Two crystallographically independent dpds ligands, both adopting the bis-monodentate bridging mode, connect two Cu(II) ions to form a one-dimensional zigzag chain-like coordination polymer.

Mechanochromic and Solvent-Induced Luminescence of a Supramolecular Pt(II)-Bipyridine Complex with Di(4-pyridylmethyl)aminedithiocarbamate.

[Pt(bpy)(DPMACS)]Cl•3HO (•3HO) (bpy = 2,2'-bipyridine, DPMACS = di(4-pyridylmethyl)aminedithiocarbamate) was synthesized and characterized by X-ray diffraction studies, and its crystal structure displayed intermolecular Pt(II)···Pt(II) contacts of 3.471 and 5.065 Å.

Visible-Light-Photocatalyzed Self-Cyclopropanation Reactions of Dibenzoylmethanes for the Synthesis of Cyclopropanes.

A new self-cyclopropanation of 1,3-diphenylpropane-1,3-dione, leading to tetrasubstituted cyclopropane containing three contiguous stereogenic centers with high stereoselectivity, has been achieved through violet-light-emitting diode-irradiated photocatalysis, featuring both cycloaddition and a distinctive rearrangement. Diverging from conventional cyclopropanation pathways, this reaction yields a tetrasubstituted cyclopropane through unprecedented rearrangement and cascade reactions.

Cobalt(II) Single-Ion Magnet Coordinated by Double Deprotonation of 2,2'-Bipyridine-6,6'-diol Ligands.

In this study, we synthesized a new Co(II) complex, [NMe][Co(bpyO)] (), using deprotonated 2,2'-bipyridine-6,6'-diol ligands (bpyO ). This compound exhibits a significant zero-field splitting () value. The far-infrared magneto spectroscopy and high-frequency and field electron paramagnetic resonance (HFEPR) measurements indicated that compound possesses = -54.

Chlorine-containing polyacetoxybriarane diterpenoids from the octocoral .

The chemical screening of an octocoral identifed as has led to the isolation of five chlorinated briarane-type diterpenoids, including three known metabolites, gemmacolide X (1), frajunolide I (2), and fragilide F (3), along with two new analogs, 12α-acetoxyfragilide F (4) and 12α-acetoxyjunceellin (5). Single-crystal X-ray diffraction analysis was carried out to determine the absolute configurations of 1 and 2, while the structures of new compounds 4 and 5 were ascertained with 2D NMR experiments. Briaranes 1 and 3-5 were active in enhancing alkaline phosphatase (ALP) activity.

Piperidine and Pyridine Series Lead-Free Dion-Jacobson Phase Tin Perovskite Single Crystals and Their Applications for Field-Effect Transistors.

Two-dimensional (2D) organic-inorganic metal halide perovskites have gained immense attention as alternatives to three-dimensional (3D) perovskites in recent years. The hydrophobic spacers in the layered structure of 2D perovskites make them more moisture-resistant than 3D perovskites. Moreover, they exhibit unique anisotropic electrical transport properties due to a structural confinement effect.

Unraveling the Structure-Property-Performance Relationships of Fused-Ring Nonfullerene Acceptors: Toward a C-Shaped -Benzodipyrrole-Based Acceptor for Highly Efficient Organic Photovoltaics.

The high-performance Y6-based nonfullerene acceptors (NFAs) feature a C-shaped A-DA'D-A-type molecular architecture with a central electron-deficient thiadiazole (Tz) A' unit. In this work, we designed and synthesized a new A-D-A-type NFA, termed CB16, having a C-shaped -benzodipyrrole-based skeleton of Y6 but with the Tz unit eliminated. When processed with nonhalogenated xylene without using any additives, the binary PM6:CB16 devices display a remarkable power conversion efficiency (PCE) of 18.

The hamburger-shape photocatalyst: thioxanthone-based chiral [2.2]paracyclophane for enantioselective visible-light photocatalysis of 3-methylquinoxalin-2(1)-one and styrenes.

A new thioxanthone-based photocatalyst with a [2.2]paracyclophane skeleton and planar chirality has been developed. The catalyst has been successfully applied in the visible light-mediated enantioselective aza Paternò-Büchi reactions of quinoxalinone and styrenes to produce azetidines.

Synthesis of Two-Dimensional (Cu-S) Metal-Organic Framework Nanosheets Applied as Peroxidase Mimics for Detection of Glutathione.

Facilely synthesized peroxidase-like nanozymes with high catalytic activity and stability may serve as effective biocatalysts. The present study synthesizes peroxidase-like nanozymes with multinuclear active sites using two-dimensional (2D) metal-organic framework (MOF) nanosheets and evaluates them for their practical applications. A simple method involving a one-pot bottom-up reflux reaction is developed for the mass synthesis of (Cu-S) MOF 2D nanosheets, significantly increasing production quantity and reducing reaction time compared to traditional autoclave methods.

From citronellal to iridoids: asymmetric synthesis of iridoids and their analogues organocatalytic intramolecular Michael reactions.

A series of iridoids, including iridomyrmecin A, B, C', D', (-)-isoiridomyrmecin, (+)-7--boschnialactone, and the inside-yohimbine analogues have been synthesized from readily available, naturally occurring (-)-citronellal the key step reaction of metathesis, organocatalysis, and subsequent transformations, such as reduction, lactonization, alkylation, Pictet-Spengler reaction and lactamization. Notably, the use of DBU as an additive in the organocatalytic intramolecular Michael reaction of an aldehyde ester with Jørgensen-Hayashi catalysts resulted in better stereoselectivity than the conditions using acetic acid as an additive. The structures of three products have been unequivocally established with single-crystal X-ray crystallographic analyses.

Sinulariaone A: a novel diterpenoid with a 13-membered carbocyclic skeleton from an octocoral species.

Chemical composition screening of an octocoral identified as species led to the isolation of a novel diterpenoid, sinulariaone A (1), featuring a 13-membered carbocyclic skeleton. The structure of 1 was established by spectroscopic elucidation, computed calculation, and X-ray diffraction analysis. Moreover, a single-crystal X-ray diffraction analysis of chlorofurancembranoid B (2), obtained in our previous study from the same octocoral species, was reported for the first time to demonstrate the absolute configuration.

Briavioids E-G, Newly Isolated Briarane-Diterpenoids from a Cultured Octocoral .

The chemical screening of a cultured soft coral, , led to the isolation of eight natural, briarane-related diterpenoids, including three unreported metabolites, briavioids E-G (-), and five known briaranes, briacavatolides B () and C (), briaexcavatin L (), briaexcavatolide U () and briarenol K (). The structures of briaranes - were established using spectroscopic methods. The absolute configuration of briavioid A (), obtained in a previous study, was reported for the first time in this study by a single-crystal X-ray diffraction analysis using a copper radiation source.

A linear Di-coordinate boron radical cation.

The pursuit of di-coordinate boron radical has been continued for more than a half century, and their stabilization and structural characterization remains a challenge. Here we report the isolation and structural characterization of a linear di-coordinate boron radical cation, achieved by stabilizing the two reactive atomic orbitals of the central boron atom by two orthogonal π-donating and π-accepting functionalities. The electron deficient radical cation undergoes facile one-electron reduction to borylene and binds Lewis base to give heteroleptic tri-coordinate boron radical cation.

Supramolecular assembly and structural transformation of d-metal complexes containing (aza-15-crown-5)dithiocarbamate.

The reaction of potassium (aza-15-crown-5)dithiocarbamate (KONCS) and (MeS)AuCl gave the dinuclear complex [Au(ONCS)], which underwent structural transformation upon heating to rearrange into the hexanuclear complex [Au(ONCS)]. Under similar reaction conditions, KONCS reacted with AgNO or [Cu(CHCN)]ClO to give the 1-D coordination polymer [Ag(ONCS)] (1) and the tetranuclear complex [Cu(ONCS)] (2), respectively. It is noted that upon heating a similar structural transformation process occurs from tetranuclear complex 2 to the octanuclear complex [Cu(ONCS)] (2'), connected by a weak Cu⋯S contact of 2.

Surficial grafting of organoimido moieties enhances the capacity performance of oxometallic clusters.

Molybdenum trioxide (MoO) with a theoretical specific capacity of 1117 mA h g is widely considered a promising anode material for lithium-ion batteries. However, the irreversible conversion reactions, low electrical conductivity, and detrimental volume expansion upon Li intercalation between the one-dimensional layered structures of MoO hinder its practical implementation. Herein, we report a facile synthetic protocol that allows surficial modification by replacing the terminal and bridging oxo groups of molybdenum oxide clusters.

Stereoselective Cyclization Cascade of Dihydroquinoxalinones by Visible-Light Photocatalysis: Access to the Polycyclic Quinoxalin-2(1)-ones.

An intriguing stereoselective visible-light photocatalysis of dihydroquinoxalinone derivatives has been realized via cyclization with or without the solvolysis cascade. The reactions provided the polycyclic ring structures with efficient formation of multiple bonds and with high stereoselectivity. X-ray crystallography unequivocally determined the structures of five polycyclic products.

Total Synthesis of Ulodione A via a Double-Alkylation and DABCO Promoted Ring-Expansion Rearrangement Sequence.

First total synthesis of ulodione A has been achieved via the key-step reactions of DIPEA-promoted dialkytion of 1,3-cyclopentadione with a bromonitroolefin and DABCO promoted/catalytic semipinacol-like ring-expansion rearrangement, with regioselective transformation of the nitrocyclohexane intermediates to their cyclopentenone counterparts via a sequence of reactions in a one-pot operation. Structures of six products were unequivocally established by X-ray crystallography.

Phonon-induced relaxation mechanisms are changed by a chelating effect in a Co single-ion magnet.

It is well known that phonon-induced relaxation processes play a significant role in accelerating magnetization relaxation in the low-temperature regime. Unfortunately, many SIMs (single-ion magnets) suffer from being quenched by these mechanisms such that neither out-of-phase signals nor magnetization hysteresis can be readily observed. Nevertheless, because it involves molecular motions at low-frequency (low-energy) levels, methods for synthetically controlling this factor have not yet been addressed by chemists.

A mild one-pot transformation of nitroalkanes to ketones or aldehydes a visible-light photocatalysis-hydrolysis sequence.

Using a visible-light photoredox catalysis strategy with household decorative blue LEDs and the additives EtN and DIPEA, as well as the subsequent hydrolysis sequence, a mild one-pot process for the direct transformation of nitroalkanes to the corresponding ketones and aldehydes, constituting a Nef-like reaction, has been developed. It is worth noting that by using an appropriate photocatalyst (, [Ir(dtbbpy)(ppy)]PF) and the extra additive EtN with the combination of DIPEA and Mg(ClO) in i-PrOH (instead of CHCN), the transformation of nitroalkanes to the corresponding oximes, rather than nitrones, can be markedly more effective. The oximes can then be hydrolyzed to ketones by reaction with CuCl·2HO in a pH 7 buffer solution.

Control of the Organocatalytic Enantioselective α-Alkylation of Vinylogous Carbonyl Enolates for the Synthesis of Tetrahydropyran Derivatives and Beyond.

The organocatalytic α-alkylation of vinylogous carbonyl compounds to hydroxynitroolefins for the synthesis of hemiacetals was realized with excellent enantioselectivities and in high yields. High diastereoselectivity (up to >20:1) has been accomplished with the addition of EtN. The α- and γ-alkylation of vinylogous ketone against nitroolefins displayed high but opposite facial selectivities.

8-Hydroxybriaranes from Octocoral (Briareidae) (Kükenthal, 1908).

Chemical investigation of the octocoral , collected in the Ie Island, Okinawa, Japan, resulted in the isolation of a new briarane-type diterpenoid, briastecholide A (), as well as the previously reported metabolites, solenolide C () and briarenolide S (). The structures of briaranes - were characterized through spectroscopic analysis, and the absolute configuration of was corroborated by a single-crystal X-ray diffraction analysis. Briarane exhibited bioactivity against the protein expression of inducible nitric oxide synthase (iNOS).