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Catalysts belonging to the IB group for propylene epoxidation have garnered significant attention and have been extensively developed in the chemical industry. In this study, spin-polarized density functional theory (DFT) calculations combined with a U correction were performed to study propylene epoxidation on the Ag 2 O(111) surface with and without Cu or Au doping. Our calculations revealed a dual propylene epoxidation mechanism: the allylic hydrogen stripping (AHS) route and the intermediary propylene oxametallacycle (OMMP) route. The doped Cu or Au sites on the Ag 2 O(111) surface exhibited superior adsorbate activity, which also influenced the activity of adjacent surface O suf sites. On the Cu-Ag 2 O(111) surface, the O suf site exhibited the lowest basicity, favoring the OMMP route. Conversely, on the Au-Ag 2 O(111) surface, the O suf site had relatively stronger basicity, which favored the AHS route. Furthermore, energetic span model analysis was carried out and showed that product selectivity followed different patterns depending on the doping: acrolein > acetone > propanal ≅ PO on the pure surface, acrolein > PO > propanal ≅ acetone on the Cu-doped surface, and acrolein > acetone > propanal > PO on the Au-doped surface. Notably, acrolein was prone to complete combustion to carbon dioxide, which became the primary product on both doped and undoped Ag 2 O(111) surfaces. While the selectivity of PO can be enhanced slightly by the doping of Cu, unfortunately, the selectivity of PO can be reduced by the doping of Au. This study aims to provide insights into the nature of IB group catalysts for propylene epoxidation, which mainly regulate the lower basicity of lattice oxygen through doping promoters and optimize the industrial yield of PO.

Gold nanoparticles (AuNPs) play a key role in the field of nanomedicine due to their fascinating plasmonic properties as well as their great biocompatibility. An intriguing application is the use of plasmonic photothermal therapy (PPTT) mediated by anisotropic AuNPs irradiated with a near-infrared (NIR) laser for treating ocular diseases in ophthalmology. For this purpose, bipyramidal-shaped AuNPs (BipyAu), which were surface-functionalized with three different organic ligands (citrate, polystyrene sulphonate (PSS), and cetyltrimethylammonium bromide (CTAB)), were synthesized. The long-term storage stability was assured, in terms of minimal variation in aspect ratio and localized surface plasmon resonance. Better performance was achieved with BipyAu@citrate and BipyAu@PSS NPs. PPTT experiments mediated with the synthesized BipyAu NPs demonstrated that BipyAu@citrate provided the highest value of temperature increase (40 °C at 2.0 W cm -2 ) after 15 min of 808 nm NIR laser irradiation. The potential future clinical application in ophthalmology was assessed by in vitro cytotoxicity analysis, confirming that BipyAu@citrate NPs were biocompatible for the three major corneal cell types. Furthermore, ex vivo analysis was performed by treating pig corneas with BipyAu@citrate NPs (0.18 μg Au) and subsequent NIR laser irradiation at 808 nm for 15 min, showing distortions in the collagen type I fibrils at the ultrastructural level and promoting the flattening of the corneal surface after treatment, without inducing cell cytotoxicity. This work suggests that a precise control of the fibril distortions can be provoked by PPTT mediated with BipyAu@citrate in the NIR region, paving the way for nanomedicine to correct common deficiencies in corneal diseases.

An interzeolite conversion (IZC) method was developed for the rapid synthesis of Cu-SAPO-34 from SAPO-37, achieving isolated Si distribution and optimized Cu states. The resulting Cu-SAPO-34 exhibited exceptional NH 3 -SCR performance, with over 90% NO conversion from 200-600 °C due to proper acidity and Cu status generated from the isolated Si.

A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidative esterification of aromatic aldehydes and alcohols has been developed, in which the in situ formed pentacoordinate sulfide derived from readily available and inexpensive sodium trifluoromethanesulfinate and oxygen acts as the photocatalyst, and the corresponding aromatic esters were provided in moderate to good yields. The present method is an economical and environmentally friendly protocol.

Synthesis of an intrinsically chiral cofacial ABCD-Pt(II)-porphyrin (Por) dimer was achieved by the simple Pt-templated synthesis of Por, followed by Suzuki-Miyaura cross-coupling. The isolated enantiomers exhibited bright red circularly polarized phosphorescence with a B CPP value above 10 1 M -1 cm -1 .

It is well known that the performance of some key catalytic reactions has a strong dependence on metal catalyst surfaces. In the current work, this concept is further extended to the CuPd alloy-supported zirconium oxide inverse catalyst for CO 2 hydrogenation to methanol. A combined DFT and microkinetic simulation study reveal that both the metal substrate surface and the precise exposed Cu or Pd metal atoms on the substrate have a pivotal influence on the catalytic mechanism and performance of the inverse catalyst for CO 2 hydrogenation to methanol. Herein, CuPd(100), (111), and (110) surfaces with either Cu and Pd terminations have been examined, which provided five metal substrates as support for the inverse catalyst. Three different mechanisms, including the formate pathway, RWGS + CO-hydro pathway, and CO 2 direct activation pathway, are explored under the same conditions; they take place at the interfacial sites between the metal alloy and oxide. The calculations indicated that the inverse catalyst with the CuPd(100) substrate demonstrates better performance than those with CuPd(110) and (111) for both formate and RWGS + CO-hydro mechanisms. Conversely, the reaction pathway is more sensitive to exposed atoms on the metal substrate. The best inverse catalyst, Zr 3 O 6 /CuPd(100) with either Cu or Pd terminations, demonstrated a methanol formation TOF above 0.30 site -1 s -1 and the selectivity was above 90% at 573 K, as evaluated from microkinetic simulation. The coverage analysis indicates the most populated species is HCOO*, which is consistent with experimental reports. Both kinetic and thermodynamics control steps are identified from DRC analysis for the best performing catalysts. Overall, the current study confirms the catalytic performance of the inverse Zr 3 O 6 /CuPd catalyst and demonstrates the tunable effects of the metal alloy substrate, which can facilitate effective optimization.

Hydrochlorofluorocarbons (HCFCs) are important greenhouse gases and ozone-depleting substances. Thus, a thorough understanding of their atmospheric fate is essential for preventing and controlling atmospheric pollution. Herein, the atmospheric transformation mechanism of CF 3 CH 2 CClF 2 (HCFC-235fa) by the OH radical and the Cl atom was carried out at the dual-level of CCSD(T)/aug-cc-pVTZ//M06-2X/6-311+G(d,p). The reaction rate coefficients were calculated using the multistructural canonical variational transition state theory with small curvature tunneling (MS-CVT/SCT) at 200-1000 K. The k MS-CVT/SCT (CF 3 CH 2 CClF 2 + OH) and k MS-CVT/SCT (CF 3 CH 2 CClF 2 + Cl) values are 9.05 × 10 -15 and 1.95 × 10 -17 cm 3 molecule -1 s -1 at 297 K, respectively. The results show that the role of OH is more important than Cl in the degradation of CF 3 CH 2 CClF 2 . The atmospheric lifetimes (83 days-77.93 years), ozone destruction potential (0.001-0.023), and global warming potentials (GWP 100 = 21.06-5157.35) of CF 3 CH 2 CClF 2 were assessed, and these results indicate that CF 3 CH 2 CClF 2 is atmospherically persistent and environmentally unfriendly. The evolution mechanisms of CF 3 C·HCClF 2 , CF 3 C(OO˙)HCClF 2 , and CF 3 C(O˙)HCClF 2 in the presence of O 2 , HO 2 ˙, and NO were investigated and discussed. The resulting products of CF 3 CH 2 CClF 2 are mostly highly oxidized multi-functional compounds in the forms of aldehydes, ketones, and organic nitrates. A computational assessment of acute and chronic toxicities was performed at three levels of nutrition in order to improve the understanding of the potential toxicity of CF 3 and its degradation products to the aquatic environment. The acidification potential of CF 2 CClF 2 and its degradation products to the aquatic environment. The acidification potential of CF 3 CH 2 CClF 2 was calculated to be 1.141 and presumed to contribute to the formation of acid rain. The results may contribute to describing HCFCs' atmospheric fate, persistence, and environmental risks.

The comprehensive utilization of sustainable green energy is essential to face the global energy and environmental crisis. The oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and electrocatalytic urea synthesis (EUS) are the pivotal electrocatalytic processes, necessitating the development of low-cost electrocatalysts with high efficiency. Small-sized transition metal oxide (TMO) clusters have attracted a lot of attention because of their exceptional qualities, such as exhibiting a dense array of low-coordinated metal active sites ( e.g. abundant metal cation defects and oxygen vacancy), amorphous structures with high surface energy, high atom utilization efficiency, and cost-effectiveness. Furthermore, the synergistic actions between metal clusters and TM-N x single atom active sites remarkably boost up the electrocatalytic performances, corroborated by density functional theory (DFT). More efforts in this comprehensive feature article are expected to achieve insights into the fundamental understanding of electrocatalytic reaction mechanisms in our lab and serve as a guide for creating cutting-edge electrocatalysts of transition metal oxide clusters.

Polyoxometalates (POMs), representing anionic metal-oxo clusters, display diverse properties depending on their structures, constituent elements, and countercations. These characteristics position them as promising catalysts or catalyst precursors for electrochemical carbon dioxide reduction reaction (CO 2 RR). This study synthesized various salts-TBA + (tetra- n -butylammonium), Cs + , Sr 2+ , and Ba 2+ -of a dipalladium-incorporated POM (Pd2, [γ-H 2 SiW 10 O 36 Pd 2 (OAc) 2 ] 4- ) immobilized on a carbon support (Pd2/C). The synthesized catalysts-TBAPd2/C, CsPd2/C, SrPd2/C, and BaPd2/C-were deposited on a gas-diffusion carbon electrode, and the CO 2 RR performance was subsequently evaluated using a gas-diffusion flow electrolysis cell. Among the catalysts tested, BaPd2/C exhibited high selectivity toward carbon monoxide (CO) production ( ca. 90%), while TBAPd2/C produced CO and hydrogen (H 2 ) with moderate selectivity ( ca. 40% for CO and ca. 60% for H 2 ). Moreover, BaPd2/C exhibited high selectivity toward CO production over 12 h, while palladium acetate, a precursor of Pd2, showed a significant decline in CO selectivity during the CO 2 RR. Although both BaPd2/C and TBAPd2/C transformed into Pd nanoparticles and WO x nanospecies during the CO 2 RR, the influence of countercations on their product selectivity was significant. These results highlight that POMs and their countercations can effectively modulate the catalytic performance of POM-based electrocatalysts in CO 2 RR., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The self-assembly of d 8 transition metal complexes is essential for the development of optoelectronic and sensing materials with superior photofunctional properties. However, detailed insight into the electronic delocalization of excited states across multiple molecules, particularly in comparing 5d 8 (Pt(ii)) and 4d 8 (Pd(ii)) systems, remains ambiguous but important. In this study, we have successfully evaluated the differences in the excited-state delocalization and thermal responses of self-assembled Pt(ii) and Pd(ii) complexes. Although the complexes presented herein, K[M(CN) 2 (dFppy)]·H 2 O (M = Pt or Pd, dFppy = 2-(4,6-difluorophenyl)pyridinate), are crystallographically isomorphous with similarly short metal⋯metal contacts, only the Pt(ii) complex exhibited thermal equilibria between delocalized excited states, resulting in a drastic thermochromic luminescence with a red-shift of greater than 100 nm. In contrast, the dimeric localized emission from the Pd(ii) complex showed a significant increase in the quantum yield upon cooling, approaching almost unity., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Porous molecular crystals (PMCs) have gained significant importance as next-generation functional porous materials. However, the selective crystallisation of the PMC phase remains a challenge. Herein, we have systematically controlled the stability of the luminescent PMC phase prepared using the luminescent Pt(II) complex [Pt(pbim)(N^O)] (pbim = 2-phenylbenzimidazolate, N^O = N-heteroaryl carboxylate) with Pt⋯Pt electronic interactions. The PMC phase formation varied significantly among the complexes depending on the heteroaryl group of the ancillary N^O ligand; the oxazolyl-bearing complex did not form a PMC phase, whereas the pyrazyl- and 5-fluoropyridyl-bearing complexes spontaneously formed a porous structure. This difference was rationalised by the π-stacking capability of the heteroaryl group of the ancillary ligand. Furthermore, owing to the presence of the one-dimensional Pt⋯Pt chains in this PMC phase, the photophysical properties of PMCs resulting from the Pt⋯Pt interactions were also significantly changed by the ancillary ligands.

The immobilization of biocatalysts on inorganic supports allows the development of bio-nanohybrid materials with defined functional properties. Gold nanomaterials (AuNMs) are the main players in this field, due to their fascinating shape-dependent properties that account for their versatility. Even though incredible progress has been made in the preparation of AuNMs, few studies have been carried out to analyze the impact of particle morphology on the behavior of immobilized biocatalysts. Herein, the artificial peroxidase Fe(iii)-Mimochrome VI*a (FeMC6*a) was conjugated to two different anisotropic gold nanomaterials, nanorods (AuNRs) and triangular nanoprisms (AuNTs), to investigate how the properties of the nanosupport can affect the functional behavior of FeMC6*a. The conjugation of FeMC6*a to AuNMs was performed by a click-chemistry approach, using FeMC6*a modified with pegylated aza-dibenzocyclooctyne (FeMC6*a-PEG 4 @DBCO), which was allowed to react with azide-functionalized AuNRs and AuNTs, synthesized from citrate-capped AuNMs. To this end, a literature protocol for depleting CTAB from AuNRs was herein reported for the first time to prepare citrate-AuNTs. The overall results suggest that the nanomaterial shape influences the nanoconjugate functional properties. Besides giving new insights into the effect of the surfaces on the artificial peroxidase properties, these results open up the way for creating novel nanostructures with potential applications in the field of sensing devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Proton-conducting polysilsesquioxane oligomers with core-shell structures consisting of hydrophilic silica-rich cores surrounded by an organic layer with sulfonic and phosphonic acid groups were synthesized. They were crosslinked by mixing with phosphoric acid and aluminum ions to form a hydrophilic Al-O-P framework. The resulting polymers were clear, uniform, flexible, and exhibited a high proton conductivity above 100 °C in non-humidified low-humidity air (∼22 mS cm -1 at 120 °C and ∼1%RH) because of their high sulfonic acid concentration and high water retention capability.

Using CO 2 as a mild oxidizing agent in propane dehydrogenation (PDH) presents an attractive pathway for the generation of propene while maintaining high selectivity. Cr 2 O 3 is one of the most important catalysts used for the CO 2 -assisted PDH process. In this study, the doping of Cr 2 O 3 with single atoms such as Ge, Ir, Ni, Sn, Zn, and Zr was used for the PDH process. The introduction of dopants significantly modifies the electronic structure of pristine Cr 2 O 3 , leading to substantial alterations in its catalytic capabilities. The dehydrogenation reactions were explored both in the absence and presence of CO 2 . The addition of CO 2 introduces two distinct pathways for PDH. On physisorbed CO 2 surfaces, Ge and Ni-Cr 2 O 3 enhance dehydrogenation. On the dissociated surface, the CO* and O* species actively participate in the reaction. All doped surfaces exhibit low energy barriers for dehydrogenation, except undoped Cr 2 O 3 on dissociated CO 2 surfaces. The Ni-Cr 2 O 3 surface emerges as the most active surface for dehydrogenation of propane in all scenarios. Additionally, the catalytic surface is re-oxidized through H 2 release, and doped surfaces facilitate coke removal via the reverse Boudouard reaction more efficiently than undoped Cr 2 O 3 . Microkinetics simulations identify the removal of the first H-atom as the rate-determining step. CO 2 reduces the apparent activation energy, directly impacting C 3 H 8 conversion and C 3 H 6 formation. This study offers a decisive description of Cr 2 O 3 modification for the CO 2 -assisted PDH process.

A Pd 3 Bi intermetallic compound (IMC) was photocatalytically deposited onto the gallium oxide (Ga 2 O 3 ) surface at room temperature. Conventional impregnation and reduction methods were difficult for the formation of the Pd 3 Bi IMC on Ga 2 O 3 , highlighting the importance of the photodeposition approach. The Pd 3 Bi-loaded Ga 2 O 3 photocatalyst exhibited 84% selectivity in methane-to-ethane conversion with hydrogen production in the presence of water vapour.

Optically active oligo( o -phenylene)-layered molecules were synthesized from planar chiral enantiopure [2.2]paracyclophane. Their structures and optical properties were characterized by experimental and theoretical approaches. The axial chiralities between phenylene rings of the oligo( o -phenylene)s were controlled by the planar chirality to form one-handed helical structures. The o -quinquephenyl-layered molecule was emissive, and circularly polarized luminescence was observed with a high anisotropy factor (| g lum | value) of 0.012.

A coordination polymer, [Cu(SCN)(iqi)] n (iqi = isoquinoline), containing copper(I) thiocyanate and a nitrogen-containing π-conjugated ligand, iqi, has been synthesized and its physical properties were evaluated. This coordination polymer has a two-dimensional (2D) sheet structure consisting of copper(I) thiocyanate and shows photoluminescence derived from 3 MLCT and photoconductive properties.

Molecular crystals of Pt(II) complexes with metallophilic interactions can provide bright assembly-induced luminescence with colour tunability. However, the brittleness of many of these crystals makes their application in flexible optical materials difficult. Herein, we have achieved the elastic deformation of crystals of polyhalogenated Pt(II) complexes exhibiting bright assembly-induced luminescence. A crystal of [Pt(bpic)(dFppy)] (Hbpic = 5-bromopicolinic acid, HdFppy = 2-(2,4-difluorophenyl)pyridine) and a co-crystal of [Pt(bpic)(dFppy)] and [Pt(bpic)(ppy)] (Hppy = 2-phenylpyridine) were found to exhibit significant elastic deformation due to their highly anisotropic interaction topologies. While the crystal of [Pt(bpic)(dFppy)] exhibited monomer-based ligand-centred 3 ππ* emission with an emission quantum yield of 0.40, the co-crystal exhibited bright, triplet metal-metal-to-ligand charge transfer ( 3 MMLCT) emission owing to Pt⋯Pt interactions, thereby achieving a significantly higher emission quantum yield of 0.94.

A series of Pt(II) complexes bearing N-heterocyclic carbenes, [Pt(CN) 2 (Rim-Mepy)] (Rim-MepyH + = 3-alkyl-1-(4-methyl-(2-pyridinyl))-1 H -imidazolium, R = Me, Et, i Pr, or t Bu), exhibits triboluminescence in the visible range from blue to red, as well as the corresponding intense photoluminescence. Remarkably, among the complexes, the i Pr-substituted one exhibits chromic triboluminescence behaviour during the process of rubbing and also vapour exposure.

Herein, we report the synthesis and chiroptical properties of 2-azatriptycenes and their platinum(II) complexes, which represent the first examples of heterotriptycenes and metallotriptycenes that exhibit circularly polarized fluorescence and phosphorescence (CPF and CPP). Theoretical studies for CPF and CPP strongly support the experimental findings.

Boronate assemblies, derived from benzene-1,4-diboronic acid, showed room-temperature phosphorescence (RTP) in both the solid-state and dispersions, being quite sensitive to the preparation conditions. Our chemometrics-assisted quantitative structure-property relationship (QSPR) analysis between the nanostructure and RTP behavior of boronate assemblies led us not only to understand their RTP mechanism but also to predict the RTP properties of unknown assemblies from the PXRD patterns.

The low-temperature activation of methane is highly important as a reaction that can dissociate the strongest C-H bond and convert it into useful compounds. This study demonstrated that supported platinum oxide was found to activate methane near room temperature and selectively afford methanol in the presence of oxygen.

Lithium-Sulfur (Li-S) batteries have attracted much attention as next-generation batteries due to their high theoretical energy density. However, lithium polysulfide generated during the discharge loses intimate electrical contact with the carbon matrix due to its high solubility in the electrolyte, causing a high charge transfer resistance and slow redox kinetics for the discharge reactions, resulting in a low rate capability. A cathode additive having a strong chemical adsorbing site toward the polysulfide can effectively inhibit their dissolution. We now report a dual additive of lithium titanium oxide (LTO) and sulfurized polyacrylonitrile (SPAN). LTO provides a rapid charge transfer and a fast Li + ion transfer in the cathode. On the other hand, SPAN helps to enhance the polysulfide adsorption capability. This dual additive system synergistically supplies the cathode with a strong polysulfide adsorption capability and fast redox kinetics. As a result, the dual additive exhibits high discharge capacities of 1430 mA h g -1 at 0.1C and 1200 mA h g -1 at 0.5C at the high-sulfur-loading cathode of 5.0 mg cm -2 . Our findings demonstrated the manufacturing of the cathode with a strong polysulfide adsorption capability and a fast redox reaction which could then effectively improve the rate performance of the Li-S batteries.

A regioselective Rh(III)-catalyzed C-H bond naphthylation and cascade directing group (DG) transformation has been realized with aryl imidates and oxa bicyclic alkenes. Diverse naphthalene-substituted aromatic esters were synthesized fruitfully. The DG transformation into ester endows the strategy with chances of further C-H bond functionalization and derivatization. Preliminary mechanistic studies demonstrate that the ester carbonyl oxygen possibly originates from the corresponding oxa bicyclic alkene.

Halogenated phenols are highly toxic chemicals with serious health risks, and the removal of these persistent environmental pollutants remains a challenge. Based on quantum chemistry calculations, the homogeneous/heterogeneous degradation mechanism and kinetics of C 6 X 5 OH (X = F, Cl, and Br) initiated by ˙OH radicals in the gas phase and TiO 2 cluster surfaces are investigated in this work. Four ˙OH-addition and one proton-coupled electron-transfer (PCET) reaction channels for each halogenated phenol were found and the ˙OH-addition channels were more favorable than the PCET pathway without TiO 2 clusters. At 296 K, the calculated total rate constant for ˙OH with C 6 F 5 OH in the atmosphere well agreed with the limited experimental data of (6.88 ± 1.37) × 10 -12 cm 3 molecule -1 s -1 . The lifetimes of C 6 F 5 OH, C 6 Cl 5 OH, and C 6 Br 5 OH were about 12.04-12.86 h at 296 K, which favored their medium-range transport in the atmosphere. In the presence of (TiO 2 ) n clusters ( n = 4, 6, 8, 12, and 16), the PCET mechanism for hydrogen transfer reaction of C 6 F 5 OH with ˙OH radicals was changed from the previous four-electron/three-center into four-electron/two-center, which results in the PCET pathway becoming more favorable than the ˙OH-addition channels. Meanwhile, the heterogeneous degradation rate constants of C 6 F 5 OH were accelerated by more than 10 orders of magnitude within 200-430 K compared with those of the naked reaction. The effects of (TiO 2 ) n cluster ( n = 4, 6, 8, 12, and 16) size on the degradation rates were analyzed at 200-430 K, and the reaction on the (TiO 2 ) 8 cluster had a faster rate. The subsequent reactions including the bond cleavage of the benzene ring and O 2 addition or abstraction were studied. This work provides new insights into halogenated aromatic atmospheric chemistry and nanoscale TiO 2 photocatalysis in air or wastewater management.

Three different reaction pathways are found for the reaction of bromine atom (Br) with the lowest-energy structure of the water trimer [ uud -(H 2 O) 3 ], initially using the MPW1K-DFT method. The three bromine pathways have closely related geometries and energetics, analogous to those found for the fluorine and chlorine reactions. The lowest-energy pathway of the Br + uud -(H 2 O) 3 reaction was further investigated using the "gold standard" CCSD(T) method and the correlation-consistent basis sets up to cc-pVQZ(-PP). Based on the CCSD(T)/cc-pVQZ(-PP)//CCSD(T)/cc-pVTZ(-PP) results, the Br + (H 2 O) 3 reaction is endothermic by 33.3 kcal mol -1 . The classical barrier height is 29.0 kcal mol -1 between the reactants and the exit complex, and there is no barrier for the reverse reaction. The Br⋯(H 2 O) 3 entrance complex is found to lie 4.7 kcal mol -1 below the separated reactants, and the HBr⋯(H 2 O) 2 OH exit complex is bound by 6.4 kcal mol -1 relative to the separated products. This potential energy profile is further corrected by the zero point energies and spin-orbit coupling effects. Structurally, the Br + (H 2 O) 3 stationary points can be derived from those of the simpler Br + (H 2 O) 2 reaction by judiciously appending a H 2 O molecule. The Br + (H 2 O) 3 potential energy profile is compared with the Br + (H 2 O) 2 and Br + H 2 O reactions, as well as to the valence isoelectronic Cl + (H 2 O) 3 and F + (H 2 O) 3 systems. It is reasonable to expect that the reactions between the bromine atom and larger water clusters would be similar to the Br + (H 2 O) 3 reaction.

The speciation of both redox reactive and volatile selenium (Se) compounds, barely reported in pristine aquatic environments, has never been investigated in remote alpine lakes, considered as sensitive ecosystems to detect the effect of global change. This work presents an integrated investigation on Se distribution and speciation conducted in 20 high altitude pristine lakes from the central-western Pyrenees. Five seasonal sampling campaigns were carried out after snowmelt (June/July) and in early fall (October) for the period 2017-2019. Concentrations of total dissolved Se (TDSe) ranged from 7 to 78 ng L -1 , with selenate being ubiquitously observed in most cases (median of 61% of TDSe). Selenite was only occasionally detected up to 4 ng L -1 , therefore a fraction of TDSe was presumably in the forms of elemental Se(0) and/or selenides. Depth profiles obtained in different lakes showed the occurrence of such Se(-II, 0) pools in bottom hypoxic to anoxic waters. The production of volatile Se compounds presented a low median total concentration (TVSe) of 33 pg L -1 (range 3-120 pg L -1 ), mainly in the form of dimethylselenide in subsurface samples (median of 82% of TVSe). The Se concentration in lake waters was significantly correlated with the sulphate concentration ( ρ = 0.93, p < 0.0001), demonstrating that it is influenced by erosion and dissolution of Se and S-enriched parent bedrocks. In addition, for Se depleted alpine lake-bedrock systems, long-range transport and wet atmospheric depositions represent a major source of Se for lake waters.

Pentacene derivatives with both π-radical- and TIPS-substituents (1m and 1p) were synthesized and their photochemical properties and excited-state dynamics were evaluated. The pentacene-radical-linked systems 1m (1p) showed a remarkable improvement in photochemical stability, which was 187 (139) times higher than that of 6,13-bis(triisopropylsilylethynyl)pentacene. Transient absorption spectroscopy showed that this remarkable photostabilization is due to the ultrafast intersystem crossing induced by effective π-conjugation between the radical substituent and pentacene moiety. The relationship between π-topology and the photochemical stability is also discussed based on the excited-state dynamics.

Modulating the active sites for controllable tuning of the catalytic activity has been the goal of much research, however, this remains challenging. The O vacancy is well known as an active site in reducible oxides. To modify the activity of O vacancies in praseodymia, we synthesized a series of praseodymia-titania mixed oxides. Varying the Pr : Ti mole ratio (2 : 1, 1 : 2, 1 : 1, 1 : 4) allows us to control the electronic interactions between Au, Pr and Ti cations and the local chemical environment of the O vacancies. These effects have been studied study by X-ray photoelectron spectroscopy (XPS), CO diffuse reflectance Fourier transform infrared spectroscopy (CO-DRIFTS) and temperature-programmed reduction (CO-TPR, H 2 -TPR). The water gas shift reaction (WGSR) was used as a benchmark reaction to test the catalytic performance of different praseodymia-titania supported Au. Among them, Au/Pr 1 Ti 2 O x was identified to exhibit the highest activity, with a CO conversion of 75% at 300 °C, which is about 3.7 times that of Au/TiO 2 and Au/PrO x . The Au/Pr 1 Ti 2 O x also exhibited excellent stability, with the conversion after 40 h time-on-stream at 300 °C still being 67%. An optimal ratio of Pr content (Pr : Ti 1 : 2) is necessary for improving the surface oxygen mobility and oxygen exchange capability, a higher Pr content leads to more O vacancies, however with lower activity. This study presents a new route for modulating the active defect sites in mixed oxides which could also be extended to other heterogeneous catalysis systems., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Four different reaction pathways are initially located for the reaction of Cl atom plus water trimer Cl + (H 2 O) 3 → HCl + (H 2 O) 2 OH using a standard DFT method. As found for the analogous fluorine reaction, the geometrical and energetic results for the four chlorine pathways are closely related. However, the energetics for the Cl reaction are very different from those for fluorine. In the present paper, we investigate the lowest-energy chlorine pathway using the "gold standard" CCSD(T) method in conjunction with correlation-consistent basis sets up to cc-pVQZ. Structurally, the stationary points for the water trimer reaction Cl + (H 2 O) 3 may be compared to those for the water monomer reaction Cl + H 2 O and water dimer reaction Cl + (H 2 O) 2 . Based on the CCSD(T) energies, the title reaction is endothermic by 19.3 kcal mol -1 , with a classical barrier height of 16.7 kcal mol -1 between the reactants and the exit complex. There is no barrier for the reverse reaction. The Cl⋯(H 2 O) 3 entrance complex lies 5.3 kcal mol -1 below the separated reactants. The HCl⋯(H 2 O) 2 OH exit complex is bound by 8.6 kcal mol -1 relative to the separated products. The Cl + (H 2 O) 3 reaction is somewhat similar to the analogous Cl + (H 2 O) 2 reaction, but qualitatively different from the Cl + H 2 O reaction. It is reasonable to expect that the reactions between the chlorine atom and larger water clusters may be similar to the Cl + (H 2 O) 3 reaction. The potential energy profile for the Cl + (H 2 O) 3 reaction is radically different from that for the valence isoelectronic F + (H 2 O) 3 system, which may be related to the different bond energies between HCl and HF.

Two types of boronic acid-appended D-π-A cyanostilbenes were synthesized to produce chiral boronate ensembles via dehydration with tartaric acid. The aggregation-induced high sensitivity and positional effect of the CN group on the emission properties allowed for chemometrics-coupled chiral recognition.

We synthesized new oxygen-evolving molecular Ru(II) catalysts with one or two carbazole moieties on the axial pyridyl ligands, namely [Ru(bda)(cbz-py)(py)] and [Ru(bda)(cbz-py) 2 ] [C1 and C2; bdaH 2 = 2,2'-bipyridyl-6,6'-dicarboxylic acid, py = pyridine, and cbz-py = 9-(pyridin-4-yl)-9 H -carbazole] to investigate the effect of cbz modification on the photophysical and catalytic properties of the well-known molecular catalyst [Ru(bda)(py) 2 ] (C0). The initial oxygen-evolving catalytic activities of C1 and C2 were higher than that of C0 in both a chemical reaction driven by the strong oxidant (NH 4 ) 2 [Ce(NO 3 ) 6 ] (CAN = ceric ammonium nitrate) and photochemical oxidation using a [Ru(bpy) 3 ] 2+ (bpy = 2,2'-bipyridine) photosensitizer with Na 2 S 2 O 8 as the sacrificial oxidant. The higher activities were ascribed to the electron-withdrawing cbz groups, which promoted the radical coupling reaction to form a Ru IV -O-O-Ru IV species. A unique oxygen-evolution rate change behaviour was observed for both C1 and C2 in the presence of a large excess of CAN, suggesting the competitive oxidation of the cbz moiety during the chemical oxygen evolution reaction. This work suggests that the cbz modification of an oxygen evolution molecular catalyst is a promising approach for integrating the hole accumulator near the oxygen evolution catalytic centre.

In the present work, we proved the efficacy of cellulose citrate to remove methylene blue (MB) from artificially contaminated water. MB is a widely used dye, but because of its chemical aromatic structure, it is significantly stable with quite slow biodegradation, causing consequent serious health problems for people and significant environmental pollution. Cellulose citrate, the bio-adsorbent proposed and studied by us to remediate water polluted by MB, is produced by a green, cheap and fast procedure that makes use of two abundant natural products, cellulose and citric acid. The average of two citrate groups for each glucose unit of cellulose chains allows this material to have many carboxylic groups available for interaction with the cationic dye. The characterization was carried out through FT-IR, SEM, specific surface area, pore structure parameters and zeta potential. The negative value of the zeta potential at neutral pH is consistent with the affinity of this material for the adsorption of cationic compounds like MB. The activity of the adsorbent at different times, temperatures, pH and concentrations was investigated. The process followed monolayer adsorption typical of the Langmuir model, with a maximum adsorption capacity of 96.2 mg g -1 , while for the kinetic studies the process followed a pseudo-second order model. The highest levels of adsorption were reported using solutions of dye with concentrations under 100 mg L -1 . The adsorbent can be regenerated several times without a significant loss in the adsorption capacity, and it is not strongly affected by temperature and pH, giving rise to a simple and eco-sustainable procedure for water remediation. Therefore, we conclude that cellulose citrate can be considered as a promising bio-adsorbent for the removal of MB and other cationic pollutants from the environment., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Optically active conjugated molecules bearing one-handed helical structures, in which two [4]helicenes or two phenanthrenes are stacked at terminal benzene moieties, were prepared using enantiopure [2.2]paracyclophane as a chiral scaffold. The obtained molecules exhibited excellent chiroptical properties such as circularly polarized luminescence with high disymmetry factors. Planar chiral pseudo- meta -disubstituted [2.2]paracyclophane was also optically resolved on the sub-gram-scale.

The transport and formation of fluorinated compounds are greatly significant due to their possible environmental risks. In this work, the ˙OH-mediated degradation of CF3CF2CF2CH2OH and CF3CHFCF2CH2OH in the presence of O2/NO/NO2 was studied by using density functional theory and the direct kinetic method. The formation mechanisms of perfluorocarboxylic/hydroperfluorocarboxylic acids (PFCAs/H-PFCAs), which were produced from the reactions of α-hydroxyperoxy radicals with NO/NO2 and the ensuing oxidation of α-hydroxyalkoxy radicals, were clarified and discussed. The roles of water and silica particles in the rate constants and ˙OH reaction mechanism with fluoroalcohols were investigated theoretically. The results showed that water and silica particles do not alter the reaction mechanism but obviously change the kinetic properties. Water could retard fluoroalcohol degradation by decreasing the rate constants by 3-5 orders of magnitude. However, the heterogeneous ˙OH-rate coefficients on the silica particle surfaces, including H4SiO4, H6Si2O7, and H12Si6O18, are larger than that of the naked reaction by 1.20-24.50 times. This finding suggested that these heterogeneous reactions may be responsible for the atmospheric loss of fluoroalcohols and the burden of PFCAs. In addition, fluoroalcohols could be exothermically trapped by H12Si6O18, H6Si2O7, and H4SiO4, in which the chemisorption on H12Si6O18 is stronger than that on H6Si2O7 or H4SiO4. The global warming potentials and radiative forcing of CF3CF2CF2CH2OH/CF3CHFCF2CH2OH were calculated to assess their contributions to the greenhouse effect. The toxicities of individual species were also estimated via the ECOSAR program and experimental measurements. This work enhances the understanding of the environmental formation of PFCAs and the transformation of fluoroalcohols.

Spinel-type MgMn 2 O 4 , prepared by a propylene-oxide-driven sol-gel method, has a high surface area and structured bimodal macro- and mesopores, and exhibits good electrochemical properties as a cathode active material for rechargeable magnesium batteries. However, because of its hydrophilicity and significant water adsorption properties, macroscopic aggregates are formed in composite slurry-coated cathodes when 1-methyl-2-pyrrolidone (NMP) is used as a non-aqueous solvent. Functionalising the surface with phenylphosphonate groups was found to be an easy and effective technique to render the structured MgMn 2 O 4 hydrophobic and suppress aggregate formation in NMP-based slurries. This surface functionalisation also reduced side reactions during charging, while maintaining the discharge capacity, and significantly improved the coulombic efficiency. Uniform slurry-coated cathodes with active material fractions as high as 93 wt% can be produced on Al foils by this technique employing carbon nanotubes as an electrically conductive support. A coin-type full cell consisting of this slurry-coated cathode and a magnesium alloy anode delivered an initial discharge capacity of ∼100 mA h g -1 at 25 °C., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Solid-phase extraction (SPE) based on trimethylsilyloxy-modified silica aerogel was developed for extraction of chemotherapeutic drugs from water. The developed method is easy and affordable, can be performed in separating funnel and does not require a vacuum and SPE manifold. The extraction and recovery of cyclophosphamide (CYP), dexamethasone (DEX), and paclitaxel (TAX) by the aerogel from water were investigated. The factors governing the extraction efficiency such as sample pH, sample volume, volume of eluent and concentration of analytes were studied. The LOD and LOQ of the developed method were calculated and linearity was found in the range of 4-100 μg L -1 . The extraction efficiency of the aerogel was compared to that of other SPE cartridges, Oasis HLB, Strata-X-C, C18 and polymeric reversed phase, and the aerogel showed similar or better performance than the other commercial cartridges available on the market. The developed method was also used to extract chemotherapeutic drugs spiked in hospital wastewater., Competing Interests: Authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

The key for the application of LiCoO 2 as a lithium-ion battery electrode at high voltage is to suppress the irreversible phase transformation from the layered to the spinel/rocksalt structure during cycling. The experimental study (R. Zhao, J. Zhang, G.-H. Lee, K. Zhang, V. W.-H. Lau, J.-J. Lee, I. Moudrakovski, Y.-L. Yang, F. Zou, M. Park, I. M. Hung and Y.-M. Kang, J. Mater. Chem. A, 2020, 8, 12424) demonstrated that Sn doping into LiCoO 2 effectively inhibits the undesired phase transition and ascribed the structural stability to the ability of the Sn dopant to pin the lattice thermal vibration. However, the detailed information on Sn-doped LiCoO 2 , such as atomic structures, still remains uncovered. Here, we carried out a comprehensive theoretical study on un-doped and Sn-doped LiCoO 2 with the aid of first-principles calculations. Our study shows that the un-doped and Sn-doped systems investigated in the experiment should contain Co-O vacancies and Sn prefers to be doped at the site that is near to the Co-O vacancies. The study also demonstrates that Sn-doping can significantly decrease the variation in volume and inhibit Co migration during delithiation. Additionally, Sn-doping can reduce the average activation barrier of Li diffusion. The theoretical study gives an insight into the microscopic mechanism of Sn-doping to enhance the performance of LiCoO 2 as a cathode material and is a necessary complement to the experimental study.

A new three-dimensional (3-D) inorganic metal-oxygen network vanadoborate Na3H10[Ni(H2O)2(VO)6(B10O22)2]·NH4·19H2O (1) constructed from lantern-type {(VO)6(B10O22)2} clusters, NaO6 polyhedra and NiO6 octahedra, was successfully synthesized by a hydrothermal method. In the structure, the {V6B20} clusters are linked together through NiO6 octahedral bridges, resulting in 1-D chains along the c-axis. The 1-D chains are further connected by NaO6 polyhedra to give rise to a 3-D open-framework structure. Furthermore, lots of NH4+ and H2O molecules are accommodated in the void of the structure, and may interact with the [V6B20] system via N-HO, O-HO hydrogen bonds, constructing a complex hydrogen-bonding network system. Strikingly, compound 1 exhibited a high proton conductivity of 3.22 × 10-3 S cm-1 at 50 °C under 100% RH with an activation energy of 1.66 eV.

To advance the development of atomically precise Ag and Ag-alloyed nanoclusters, it is critical to develop effective synthetic methods. Herein, we successfully extend the CTAB (cetyl trimethyl ammonium bromide) reverse micelle method to synthesize a high-purity Ag 44 (p-MBA) 30 (p-MBA = para-mercaptobenzoic acid) nanocluster and its corresponding alloy cluster Au 12 Ag 32 (p-MBA) 30 in a short time (15 min and 5 min), with a high yield of ∼83% and ∼85%, respectively. Furthermore, the mechanism regarding the reverse micelle method has been clearly elucidated. Through characterizing the reaction system by Raman spectroscopy and NMR spectroscopy techniques, it can be revealed that employing CTAB to form reverse micelles to construct a sealed chemical environment is critical for realizing the fast and high-yield synthesis.

Electronic interactions can radically enhance the performance of supported metal catalysts and are critical for fundamentally understanding the nature of catalysts. However, at the microscopic level, the details of such interactions tuning the electronic properties of the sites on the metal particle's surface and metal-support interface remain obscure. Herein, we found polarized electronic metal-support interaction (pEMSI) in oxide-supported Pd nanoparticles (NPs) describing the enhanced accumulation of electrons at the surface of NPs (superficial Pd δ - ) with positive Pd atoms distributed on the interface (interfacial Pd δ + ). More superficial Pd δ - species mean stronger pEMSI resulting from the synergistic effect of moderate Pd-oxide interaction, high structural fluxionality and electron transport activity of Pd NPs. The surface Pd δ - species are responsible for improved catalytic performance for H 2 evolution from metal hydrides and formates. These extensive insights into the nature of supported-metal NPs may open new avenues for regulating a metal particle's electronic structure precisely and exploiting high-performance catalysts., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

An optically active binuclear platinum(ii) complex based on planar chiral [2.2]paracyclophane was synthesized. The corresponding enantiomers exhibited red circularly polarized phosphorescence (CPP) with the dissymmetry factor |g lum | = 1.0 × 10 -3 . We report, for the first time, theoretical estimation of the CPP |g lum | value using relativistic calculations.

Herein, a simple and practical method for generating isoacenofuran, a new π-extended quinoidal building block, was developed. A three-step protocol involving double nucleophilic additions of alkynyllithiums to acene-2,3-dicarbaldehyde, mono-oxidation, and acid-promoted cyclization enables the generation of the target molecule, which is trapped by a dienophile to produce highly condensed acenequinones. Further transformations by double nucleophilic additions of alkynyllithium to hexacenequinone, followed by reductive aromatization, produce tetraalkynylhexacenes with a remarkably higher stability than that of the previously reported substituted hexacenes.

A redox-neutral Rh(iii)-catalyzed C-H annulation of indolyl oximes was developed. Relying on the use of various alkynyl silanes as the terminal alkyne surrogates, the reaction exhibited a reverse regioselectivity, thus giving an exclusive and easy way for the synthesis of a wide range of substituent free γ-carbolines at C3 position with high efficiency. Deuterium-labelling experiments and kinetic analysis have preliminarily shed light on the working mode of this catalytic system.

Gas-phase glycerol dehydration over WO 3 /Al 2 O 3 catalysts was investigated. WO 3 loading on γ-Al 2 O 3 significantly affected the yield of acrolein and the catalyst with 20 wt% WO 3 loading showed the highest activity. The WO 3 /Al 2 O 3 catalyst with 20 wt% WO 3 loading showed higher activity and durability than the other supported WO 3 catalysts and zeolites. The number of Brønsted acid sites and mesopores of the WO 3 /Al 2 O 3 catalyst did not decrease after the reaction, suggesting that glycerol has continuous access to Brønsted acid sites inside the mesopores of WO 3 /Al 2 O 3 , thereby sustaining a high rate of formation of acrolein. Dehydration under O 2 flow further increased the durability of the WO 3 /Al 2 O 3 catalyst, enabling the sustainable formation of acrolein. In addition, the WO 3 /Al 2 O 3 catalyst with 20 wt% WO 3 loading showed high activity for the dehydration of various polyols to afford the corresponding products in high yield., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this study, the adsorption behavior of mono-cationic acridinium derivatives on a synthetic clay mineral (Sumecton SA) was investigated. The acridinium derivatives were adsorbed on the clay surface without aggregation, as found from the changes in the absorption spectra of the acridinium derivatives with SSA and without SSA represented by two-component equilibrium systems of adsorbed and non-adsorbed components. Following the Langmuir isotherm analysis, the adsorption equilibrium constants and maximum adsorption amounts were determined for acridinium derivatives, and the Gibbs free energy change (Δ G ) was calculated to be in the range of -33.8 to 40.0 kJ mol -1 from the adsorption equilibrium constants. These results indicated that the adsorption of acridinium derivatives on the clay surface was an exergonic reaction. Moreover, thermodynamic parameters such as enthalpy change (Δ H ) and entropy change (Δ S ) were obtained from the temperature effect experiments. For all acridinium derivatives, Δ H (from -7.82 to -26.0 kJ mol -1 ) and Δ S (0.047-0.088 kJ mol -1 K -1 ) were found to be negative and positive, respectively. It was suggested that not only electrostatic interactions, but also van der Waals forces and hydrophobic interactions played an important role in the adsorption of cationic aromatic molecules on the clay surface. Because these thermodynamic parameters showed a strong correlation with the molecular cross-sectional area of acridinium derivatives, it was suggested that the contribution of hydrophobic interactions became smaller as the molecular cross-sectional area became larger., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The chemical composition of water-soluble organics in oil sands process-affected water (OSPW) is primarily composed of natural constituents of bitumen that are solubilized and concentrated during aqueous extraction of oil sands. OSPW organics are persistent and acutely toxic, and a leading remediation strategy is long-term ageing in end-pit lakes, despite limited data available on its photochemical fate. Here, direct photolysis of whole OSPW, or of its constituent fractions, was examined at environmentally relevant wavelengths (>290 nm) in bench-top studies. Changes in the chemical profiles of whole OSPW, acid- (AEO), and base-extractable organics (BEO) were characterized by liquid chromatography with ultra-high resolution mass spectrometry in negative (-) and positive (+) ionization modes. Following 18 d of irradiation, photolysis reduced the total ion intensity in all samples in both modes. The most photo-labile species included the O 2 - , O 3 - , O 4 - , O 2 chemical classes, which were depleted in whole OSPW by 93-100% after only 5 d. In positive mode, detected species were more recalcitrant than those detected in negative mode, with an average reduction across all heteroatomic classes of 75 ± 11.0% after 18 d. Estimated environmental half-lives for heteroatomic classes ranged from 57 d (O - , and O 4 S - chemical classes, which were depleted in whole OSPW by 93-100% after only 5 d. In positive mode, detected species were more recalcitrant than those detected in negative mode, with an average reduction across all heteroatomic classes of 75 ± 11.0% after 18 d. Estimated environmental half-lives for heteroatomic classes ranged from 57 d (O 4 ), with a greater recalcitrance for classes detected in positive mode compared to negative mode. Under field conditions in end-pit lakes, natural photolysis may be an important mechanism for effective OSPW remediation, and we suggest that future end-pit lakes be shallow to maximize light penetration and natural photolysis in ageing OSPW.- ) to 545 d (O 3 N + ), with a greater recalcitrance for classes detected in positive mode compared to negative mode. Under field conditions in end-pit lakes, natural photolysis may be an important mechanism for effective OSPW remediation, and we suggest that future end-pit lakes be shallow to maximize light penetration and natural photolysis in ageing OSPW.

Nitrogenous particle participation in the formation of clusters has attracted considerable attention from numerous researchers in recent years. Urea and thiourea (TU), as the common fertilizers in agriculture, have a significant impact on the atmospheric environment, whereas their implications have not been comprehended widely. Herein, we have used quantum calculations and ABCluster to explore the potential roles of thiourea and urea in particle formation events. A vital implication of these results is that they may contribute toward particle formation in marine environments and Asia region where the concentration of thiourea and urea has been increasing for a few years. Furthermore, the mechanisms of NO2 hydrolysis in the presence of thiourea and subsequent reactions were studied deeply. The results indicate that, although these reactions are not thermodynamically favorable at 298.15 K under homogeneous gas-phase conditions, thiourea may promote the hydrolysis of NO2 in heterogeneous environments containing very high concentrations of these molecules. The kinetics analysis shows that the rate constants of the hydrolysis reaction catalyzed by thiourea with N2O4-W and TU-W are about 2-5 and 1-2 orders of magnitude faster than those of the naked reaction. Thiourea nitrate and its aquo-complex were also studied, and the results suggest that the reaction produced an acid-base complex in which the trans- configuration is the final form for nitrous acid. We hope that these findings would inspire field measurements for detecting urea and thiourea in the troposphere.

Fluorocarbons have been shown experimentally by Baker and coworkers to combine with the cyclopentadienylcobalt (CpCo) moiety to form fluoroolefin and fluorocarbene complexes as well as fluorinated cobaltacyclic rings. In this connection density functional theory (DFT) studies on the cyclopentadienylcobalt fluorocarbon complexes CpCo(L)(C n F 2n ) (L = CO, PMe 3 ; n = 3 and 4) indicate structures with perfluoroolefin ligands to be the lowest energy structures followed by perfluorometallacycle structures and finally by structures with perfluorocarbene ligands. Thus, for the CpCo(L)(C 3 F 6 ) (L = CO, PMe 3 ) complexes, the perfluoropropene structure has the lowest energy, followed by the perfluorocobaltacyclobutane structure and the perfluoroisopropylidene structure less stable by 8 to 11 kcal mol -1 , and the highest energy perfluoropropylidene structure less stable by more than 12 kcal mol -1 . For the two metal carbene structures Cp(L)Co[double bond, length as m-dash]C(CF 3 ) 2 and Cp(L)Co[double bond, length as m-dash]CF(C 2 F 5 ), the former is more stable than the latter, even though the latter has Fischer carbene character. For the CpCo(L)(C 4 F 8 ) (L = CO, PMe 3 ) complexes, the perfluoroolefin complex structures have the lowest energies, followed by the perfluorometallacycle structures at 10 to 20 kcal mol -1 , and the structures with perfluorocarbene ligands at yet higher energies more than 20 kcal mol -1 above the lowest energy structure. This is consistent with the experimentally observed isomerization of the perfluorinated cobaltacyclobutane complexes CpCo(PPh 2 Me)(-CFR-CF 2 -CF 2 -) (R = F, CF 3 ) to the perfluoroolefin complexes CpCo(PPh 2 Me)(RCF[double bond, length as m-dash]CF 2 ) in the presence of catalytic quantities of HN(SO 2 CF 3 ) 2 . Further refinement of the relative energies by the state-of-the-art DLPNO-CCSD(T) method gives results essentially consistent with the DFT results summarized above.

Pentakis(dimethylsulfoxide-κ O )oxidovanadium(iv) bis(tetraphenylborate), [VO(dmso) 5 ][BPh 4 ] 2 (dmso: dimethylsulfoxide), was synthesized, and its pseudo- C 4 coordination geometry was revealed by a single-crystal X-ray method. A novel equation set was obtained for magnetic susceptibility and magnetization of the d 6 complexes, considering the axial distortion and the spin-orbit coupling for the 1 D free-ion term. The equation set enabled magnetic simulation for significantly symmetry-lowered d 2 D free-ion term. The equation set enabled magnetic simulation for significantly symmetry-lowered d 1 complexes to obtain the anisotropic g -values and also the excitation energies. In addition, conformational prediction was conducted, using the enumeration results on the basis of the group theory. The dominant conformers were predicted on the basis of the density functional theory (DFT) method, and especially, the conformer in the crystal was successfully predicted by a deep neural network method., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)