Natural gas purification requires efficient removal of acidic gases like hydrogen sulfide (H2S) and carbon dioxide (CO2), which can cause severe pipeline corrosion. This study investigates the performance of two Hofmann-type metal-organic frameworks (MOFs), Co(pyz)[Ni(CN)(4)] (ZJU-74) and its amino-functionalized derivative Co(pyz-NH2)[Ni(CN)(4)] (ZJU-75), in selective H2S recovery from natural gas mixtures. These MOFs feature one-dimensional channels, abundant open metal sites, and strategically positioned functional groups to enable remarkable selective adsorption capabilities for H2S and CO2. At 298 K and 1 bar, activated ZJU-74a and ZJU-75a exhibited impressive H2S adsorption capacities of 113.7 and 95.5 cm(3) g(-1), respectively. Breakthrough experiments demonstrated that ZJU-75a possesses longer H2S retention times (185 ming(-1)) than its prototype ZJU-74a. Both materials maintained structural integrity through multiple adsorption-desorption cycles, enabling the recovery of high-purity H2S (>99.5 %) during single desorption process. Grand canonical Monte Carlo simulations and density functional theory calculations revealed that the enhanced selectivity of ZJU-75a toward H2S stems from the extra interactions with -NH2 groups, creating high-density adsorption sites within the framework. These findings reveal that amino-functionalized Hofmann-type MOFs can be promising candidates for efficient natural gas purification and sustainable sulfur recovery.

Understanding how nuclear spin influences electronic spin relaxation in single-molecule magnets (SMMs) is essential for advancing quantum technologies. Isotopologue coordination chemistry offers a promising route to probe nuclear-spin effects, yet its role in relaxation dynamics into Single Molecule Toroic (SMT) systems remains unexplored. Here, we study two isotopically enriched ADy4 grid complexes, 164Dy4L4 (with I = 0) and 163Dy4L4 (with I = 5/2), combining μSQUID magnetometry down to 30 mK with ab initio calculations and spin-Hamiltonian modeling. Both isotopologues exhibit a pseudotoroidal ground state stabilized by noncollinear anisotropy axes and competing interactions, producing hexagonal angular maps and S-shaped hysteresis loops. The nuclear-spin-free 164Dy4L4 displays sharp quantum tunneling of magnetization (QTM) transitions, whereas hyperfine coupling in 163Dy4L4 generates a dense manifold of crossings, profoundly altering relaxation dynamics. Contrary to expectations, nuclear spins do not accelerate relaxation but promote hyperfine-mediated population transfer into the toroidal state, yielding slower dynamics and larger hysteresis openings. Temperature and sweep-rate dependences further reveal contrasting mechanisms: pure tunneling in 164Dy4L4 versus thermally assisted processes in 163Dy4L4. Overall, our findings demonstrate that nuclear spins exert a constructive and nonintuitive influence on toroidal SMMs, providing an additional lever for controlling low-temperature relaxation. Isotopically controlled lanthanide assemblies thus emerge as promising platforms for exploring quantum tunneling, spin-phonon coupling, and molecular-scale information storage/processing.

The separation of C2H2 and CO2 is highly challenging owing to their similar molecular sizes and physicochemical properties. Herein, we report two isostructural metal-organic frameworks, LIFM-712 and LIFM-713, constructed from fluorido-bridged heptanuclear [Co7F12]2+ clusters and tritopic pyridyl ligands, which feature a pyr topology. Confined BF4- counteranions synergize with bridging fluorido ligands to generate fluorine-rich pore environments, thus providing abundant C-H···F recognition sites for C2H2. LIFM-712 exhibits stronger C2H2 binding (Qst = 35.2 kJ mol-1), whereas LIFM-713 balances affinity and specific surface area, achieving a higher C2H2 uptake of 149.8 cm3 g-1 at 298 K and 1 bar. For LIFM-713, ideal adsorbed solution theory calculations afford a C2H2/CO2 selectivity up to 4.5, and breakthrough experiments demonstrate a clear separation with a 35 min g-1 separation window at 298 K. For the two Co-MOFs, theoretical simulations and in situ infrared spectra reveal that cooperative interactions between cluster-bound fluorido sites and pore-confined counteranions govern the selective adsorption of C2H2. This work highlights a synergistic fluorine-functionalization strategy for designing efficient adsorbents for challenging gas separations.

The separation of C2H2 and CO2 is highly challenging owing to their similar molecular sizes and physicochemical properties. Herein, we report two isostructural metal-organic frameworks, LIFM-712 and LIFM-713, constructed from fluorido-bridged heptanuclear [Co7F12]2+ clusters and tritopic pyridyl ligands, which feature a pyr topology. Confined BF4 - counteranions synergize with bridging fluorido ligands to generate fluorine-rich pore environments, thus providing abundant C-H & centerdot;& centerdot;& centerdot;F recognition sites for C2H2. LIFM-712 exhibits stronger C2H2 binding (Q st = 35.2 kJ mol-1), whereas LIFM-713 balances affinity and specific surface area, achieving a higher C2H2 uptake of 149.8 cm3 g-1 at 298 K and 1 bar. For LIFM-713, ideal adsorbed solution theory calculations afford a C2H2/CO2 selectivity up to 4.5, and breakthrough experiments demonstrate a clear separation with a 35 min g-1 separation window at 298 K. For the two Co-MOFs, theoretical simulations and in situ infrared spectra reveal that cooperative interactions between cluster-bound fluorido sites and pore-confined counteranions govern the selective adsorption of C2H2. This work highlights a synergistic fluorine-functionalization strategy for designing efficient adsorbents for challenging gas separations.

Constructing a favorable catalytic environment adjacent to the active center is a promising strategy for achieving efficient photocatalytic performance with the aid of the solvent effect. We report in this work that the initial rate of H-2 evolution catalyzed by Co(dmgH)(2)LCl (dmgH = dimethylglyoximate, L = 4-COOH-py, py = pyridine) can be significantly enhanced when CO2 is introduced into the reaction solution, giving an impressive turnover frequency of 0.77 min(-1) with 35 times enhancement in sharp contrast to the N-2 atmosphere. H-1 NMR, IR spectroscopy, and DFT calculation were conducted to explore the mechanistic impact of CO2 derived H2CO3 in the system. This dramatic improvement originates from the H2CO3-mediated acceleration of the protonation of the Co-I intermediate with decreased activation energy, a critical rate-determining step in the electron-transfer reactions. The protonation of the side-chain oxime group in the Co-cat is completed in advance due to CO2 acidity, while favorable hydrogen-bond interactions ensure the optimal geometric alignment for proton transfer from H2CO3 to Co-I. This study unveils mechanistic insights into hydrogen-bond network-mediated proton transfer (PT) in H-2 evolution and provides a paradigm for enhancing PT efficiency through the action of carbonic acid as a dynamic proton-transfer agent. Furthermore, it challenges the traditional view of competitive photocatalytic CO2 reduction and H-2 production via water splitting, proposing a cooperative mechanism where carbonic acid functions as a nondepleting cosubstrate to accelerate H-2 evolution.

The separation of C2H2 from CO2 remains a critical challenge because of their similar molecular dimensions and boiling points. Herein, we report two isostructural cage-based metal-organic frameworks (MOFs), LIFM-801 and LIFM-802, with Co and Ni metal nodes. Built from linear trinuclear metal nodes and tritopic pyridyl ligands, both adopt a nested cage architecture. Cage-confined tetrafluoroborate (BF4-) counteranions are immobilized within cavities via C-H···F interactions, generating fluorine-rich microenvironments as C2H2 recognition sites. At 298 K and 1 bar, LIFM-801 and LIFM-802 exhibit C2H2 uptakes of 121.4 and 113.5 cm3 g-1 with isosteric adsorption enthalpies (Qst) of 30.1 and 27.8 kJ mol-1. Ideal adsorbed solution theory (IAST) calculations yield equimolar C2H2/CO2 selectivities of 4.17 and 2.96. Dynamic breakthrough experiments demonstrate efficient C2H2/CO2 separation performance with separation windows of 23 and 22 min g-1 at 298 K. The comparable performance indicates that the separation ability is dominated by cage-confined BF4- anions, while metal node substitution enables tuning of affinity and kinetics. Grand canonical Monte Carlo (GCMC) simulations corroborate that cage-confined BF4- serves as the dominant binding site for C2H2 via C-H···F interactions. This work highlights a guest-anion confinement strategy for fluorine-rich adsorption microenvironments toward gas separations, with metal node modulation for performance optimization.

The synthesis of crystalline materials capable of precise and chemically triggered structural transformations remains a significant challenge. Herein, we report a dynamic coordination-mediated strategy for constructing a highly stable bis-acylhydrazone-linked covalent organic framework, COF-LIFM20-Zn, featuring an adjustable U-shaped pentadentate Zn coordination center. The dynamic coordination behavior of Zn2+ enables reversible interconversions between U- and W-shaped configurations through demetalation and remetalation, as evidenced by 96.2% Zn2+ removal, a remetalation efficiency of up to 97.9%, and retained reversibility over three U-W switching cycles. Furthermore, incorporation of Cu2+, which exhibits a distinct coordination preference, reprograms the framework into a J-shaped configuration. Consequently, interconversions among the U-, W-, and J-shaped configurations are triggered by metal coordination within a single crystalline framework. These coordination-programmed structural transformations systematically modulate the pore structures and metal-dependent photophysical properties of the COFs. Among them, COF-LIFM20-Zn exhibits efficient visible-light-driven NAD+ regeneration, whereas COF-LIFM20-Cu significantly suppresses the activity, enabling metal-induced configurational regulation of photocatalytic performance. This work establishes a versatile strategy for constructing reconfigurable COFs through the integration of dynamic covalent and coordination chemistry, providing new opportunities for developing adaptive crystalline materials with programmable structures and tunable functionalities.

Chiral organic molecules with pronounced chiroptical responses are of significant interest for applications ranging from bioimaging to optoelectronic devices. Herein, we report comprehensive chiroptical investigations of a compact [2.2]paracyclophane (PCP)- based macrocycle and its open precursor. While the synthesis of the structure was reported by the group of Michael Haley, chiroptical investigations were still missing. The rigid PCP core acts as a chiral template, inducing helical twisting within the conjugated diacetylene framework. Owing to its low atomic count, the compact macrocycle represents an attractive model system for combined experimental and computational studies, enabling fast DFT and TD-DFT calculations. The macrocycle and its open synthetic precursor were synthesized, structurally characterized, and, in both cases, enantiomers were separated on a chiral stationary phase HPLC. Absolute configurations were assigned through TD-DFT calculations. Optical measurements reveal enhanced conjugation and redshifted emission upon macrocyclization. Electric circular dichroism (ECD) spectra exhibit multiple intense cotton bands. Both macrocycle and open precursor display exceptionally high circularly polarized luminescence (CPL) dissymmetry factors, with glum around 10-2. Despite moderate CPL brightness, limited by the compounds' quantum yields, these results demonstrate the strong chiral amplification imparted by the PCP. The presented scaffold provides a versatile platform for probing structure-property relationships in chiral conjugated macrocycles.

A pronounced nucleophilicity in combination with a distinct redox non-innocence is a unique feature of a coordinated ligand, which in the current case, leads to unprecedented carbon-centered reactivity patterns: A carbodiphosphorane-based (CDP) pincer-type rhodium complex allows to cleave two C–Cl-bonds of geminal dichlorides via two consecutive SN2-type oxidative additions resulting in the formation of a stabilized carbene fragment. In the presence of a suitable reductant the carbene fragment can even be converted into olefines or hydrodehalogenation products in a catalytic reaction. The developed method can also be used to convert chlorofluorocarbons (CFCs) such as CH2ClF to fluoromethane and methane. The strong nucleophilic character of coordinated CDPs is also reflected in the low potential for oxidation, which favors radical reactivity and gives rise to an unique cationic C-centered radical CDP ligand, which is capable of a carbon-centered dihydrogen activation, following an unprecedented radical mechanism involving ligand-ligand-cooperativity (LLC).

The synthesis and analyses of a series of "Geländer" oligomers with perpendicularly arranged rungs are reported. The synthesis is achieved by forming the axis with a statistical end-capped oligomerization, before the banister is wrapped around it by Eglinton couplings. The intrinsic helical chiral structures are characterized by NMR spectroscopy and mass- and photo spectrometry, and for the trimer, even the solid-state structure is determined. The dimeric, trimeric, and tetrameric structures are resolved into their enantiomers and their electronic circular dichroism is studied.

The efficient separation of C2H2 from C2H2/CO2 mixtures is of significant importance for acetylene purification. Herein we present a multiply interpenetrated metal-organic framework, named LIFM-290, constructed with a Cu2 paddlewheel and a tricarboxylate linker, for C2H2/CO2 separation. LIFM-290 has 1D channels with Cu open metal sites, which are superior C2H2-favored adsorption sites. Single-component adsorption and transient breakthrough experiments demonstrate its ability to capture C2H2 from C2H2/CO2 mixtures. Theoretical calculations reveal that the open metal sites play a vital role in the selective adsorption of C2H2 via Cu-C2H2 interactions.

In this work, three silyl [PNSiNP] pincer cobalt(iii) hydrides, CoIII(H)(Cl)(PMe3)(R ' Si(NCH2PR2)2C6H4) (R ' = Me and R = Ph (1); R ' = Ph and R = Ph (2) and R ' = Me and R = iPr (3)), were synthesized. Among the three complexes, complexes 2 and 3 are new and have been characterized and analyzed. The molecular and crystal structures of complexes 2 and 3 were determined by single crystal X-ray diffraction. The catalytic activity of cobalt hydrides 1-3 for alkene hydrosilylation was evaluated, revealing similar product selectivities, but the highest catalytic activity of the three catalysts for complex 1. The selectivity can be effectively regulated by using sodium methoxide as an additive. Under optimized catalytic reaction conditions a conversion of up to 98% with up to 99/1 (b/l) product selectivity was achieved. When aryl alkenes are used as substrates, the reactions mainly follow the Markovnikov rule. When using alkyl alkene substrates, the reactions tend to form anti-Markovnikov addition products. A plausible mechanism for this catalytic reaction was proposed and partly corroborated by experiments. A four-coordinated [PNSiNP] pincer cobalt(i) complex (1c) was considered as the active species for this catalytic system. NaOMe as an additive promotes the conversion of Co-Cl bonds to Co-OMe moieties, which, in the presence of silane, may facilitate the formation of a polyhydride species and accelerate the formation of the active species [PNSiNP] pincer cobalt(i) complex (1c) in the catalytic system. Compared with our reported [PSiP] pincer Co(iii) hydride system, although the active intermediate in the catalytic cycle in both cases is the tetra-coordinated cobalt(i) complex, the selectivity of aromatic alkene hydrosilylation is reversed from anti-Markovnikov addition with [PSiP] pincer cobalt(iii) hydride as the catalyst to Markovnikov addition with complex 1 as the catalyst. The catalytic selectivity of catalysts can be regulated by adjusting the properties of supporting ligands.

A novel dinuclear silylene cobalt complex [((Me3P)(2)Co)(PMe2)(CoCl(PMe3))(Si(NCH2PPh2)(2)C6H4)] (1) supported by the [PSi(silylene)P] ligand was prepared through the reaction of N-heterocyclic [PSiP] pincer ligand L1 (HSiCl(NCH2PPh2)(2)C6H4) with Co(PMe3)(4). Complex [((Me3P)(2)Co)(2)(Si(NCH2PPh2)(2)C6H4)] (2) was formed through the reaction of complex 1 with MeLi. To the best of our knowledge, complexes 1 and 2 are the first examples of dinuclear silylene cobalt complexes supported by the [PSi(silylene)P] ligand. A new preligand L2 (SiCl2(NCH2PPh2)(2)C6H4) was synthesized, and the reaction of preligand L2 with Co(PMe3)(4) afforded silyl cobalt complex [((Me3P)(2)Co)(SiCl(NCH2PPh2)(2)C6H4)] (3). The reaction of 3 with CO delivered cobalt carbonyl complex [((Me3P)(CO)Co)(Si(NCH2PPh2)(2)C6H4)](2)O (4). The catalytic activity of cobalt complexes 1-4 on the hydrosilylation of alkenes was explored. Among the four complexes, complex 1 has the best catalytic activity. The catalytic process could be promoted with NaBHEt3 as an additive, and a complete conversion with an excellent selectivity of 98:2 (b/l) could be reached at 120 degrees C within 8 min for aryl alkenes. A possible catalytic cycle was proposed on the basis of the experimental results and literature reports, with a cobalt hydride complex as an active intermediate. The molecular structure of complexes 1-4 was determined by single-crystal X-ray diffraction analysis.

In a novel approach, 1,1 '-bis(2,3-diazabuta-l,3-dien)ferrocenophane (Fc-azine) synthesized by self-condensation of 1,1 '-Ferrocenedicarboxaldehyde hydrazone (FcDH) with the aid of Zn(OAc)2.2H2O or acetic acid at 120 degrees C under high pressure. Fc-azine as an insoluble compound was fully characterized by Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA), BrunauerEmmett-Teller analyses (BET), powder x-ray diffraction (XRD) and single crystal x-ray diffraction. The narrow band gap (Eg = 1.93 eV) and the presence of ferrocene and azine functional groups encouraged us to use Fc-azine as an advanced oxidation process (AOP) catalyst. Interestingly, the addition of Fc-azine (1 g L-1) to aqueous solutions of 50 ppm of Congo red (CR) and 10 ppm of methyl orange (MO) led to the fast degradation of CR (over 80 % in 5 min) and the slow degradation of MO (98 % in 48 h) in the dark, without additional energy sources or chemical reagents. It was found that Fc-azine can degrade CR in six cycles with high efficiency (over 80 %). CR degradation by Fc-azine can be performed in acid and basic environments (pH= 3-9), and effective MO degradation happens in slightly acidic and natural environments (pH= 5-7). Possible adsorption, reactive oxygen species production (.OH, O2.- ), and the mechanism of CR and MO degradation were also studied.

Chiral organic molecules possessing high quantum yields, circular dichroism, and circularly polarized luminescence values have great potential as optically active materials for future applications. Recently, the identification of a promising class of inherently chiral compounds was reported, namely macrocyclic 1,3-butadiyne-linked pseudo-meta[2.2]paracyclophanes, displaying high circular dichroism and related g(abs) values albeit modest quantum yields. Increasing the quantum yields in an attempt to get bright circularly polarized light emitters, the high-yielding heterocyclization of those 1,3-butadiyne bridges resulting in macrocyclic 2,5-thienyls-linked pseudo-meta [2.2]paracyclophanes is herein described. The chiroptical properties of both, the previously reported 1,3-butadiyne, and the novel 2,5-thienyl bridged macrocycles of various sizes, are experimentally recorded, and theoretically described using density-functional theory.

The emerging metal-organic frameworks (MOFs) with long persistent luminescence (LPL) have raised particular attention among researchers due to their long-lived triplet states, while most LPL materials facing the problem of low luminescence efficiency. A semiflexible tripodal ligand (1 ',1 ''-(2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)tris(pyridin-4(1H)-one), namely TTP) with intra-ligand charge transfer (ILCT) characteristic is selected to form robust LPL MOFs for keeping high luminescence efficiency. Three LPL MOFs named LIFM-130, LIFM-131 and LIFM-132 exhibit highly emissive lime green LPL at ambient conditions with the highest luminescence efficiency of 36 %. It was found that the metal halide clusters in LIFM-130 have salient heavy atom effect (HAE), which can enhance inter- and intramolecular interactions, thus helping LPL emission prominently. Periodic density functional theory (DFT) calculations reveal the participation of heavy atoms affecting luminescence, in which the bright luminescence of MOFs arises from the ligand-center n-pi* transition and metal-to-ligand charge transfer, while LIFM-130 has additional emission state of halogen-to-ligand charge transfer. This work illustrates that on the one hand, the construction of CT characterized MOFs is beneficial for the premise of LPL while maintaining high luminescence efficiency. On the other hand, the introduction of metal halide clusters into MOFs can further improve luminescence efficiency and phosphorescence lifetime synergistically by promoting ISC through HAE and reducing non-radiative transitions through the compact structure.

Three novel copper(II) complexes, 1-3, bearing dipodal bis-mercaptobenzimidazole derivatives based on ortho-, meta- or para-xylene (L1, L2, and L3) were successfully prepared and characterized by using various spectral techniques, including elemental analysis, FT-IR, H-1 NMR, and UV-Vis spectroscopy, LC-MS spectrometry and TGA. The analysis revealed that the ligand/metal molar ratio in all copper(II) complexes is 1:1 and the ligand coordinates as a neutral N-donor onto metal center. Additionally, the crystal structures of L1, L2, L3, and copper(II) complex 2 were determined using single crystal X-ray diffraction (SC-XRD) analysis. Copper(II) complexes 1-3 displayed significant stability at pH range of 4-10. The antibacterial effect of ligands and complexes was tested against both gram-negative (Escherichia coli, E. coli ATCC 25922 PTCC 1399) and gram-positive (Staphylococcus aureus, S. aureus ATCC 6538 PTCC 1112) bacterial strains. It should be noted that the complexes showed enhanced antibacterial activity (up to 99 %) when compared to their free ligands. The in vitro studies of all synthesized compounds consisted of testing them against the human colorectal carcinoma cancer cell line (HCT-116) using the MTT assay. The findings revealed that the copper(II) complexes exhibited lower CC50 values (CC50 ranging from 0.045 mM to 0.135 mM) compared to their corresponding ligands (CC50 ranging from 0.150 mM to 0.240 mM) and carboplatin (CC50 = 0.165 mM), indicating higher anticancer activity of the complexes. Additionally, DAPI staining and fluorescence spectroscopy (at three different temperatures) were performed to further examine the impact of complexes 1-3 on inducing apoptosis and to explore their interaction with DNA, respectively. The results revealed a dynamic quenching mechanism, with hydrophobic forces playing a dominant role in the binding process. The viscosity measurements indicated that all complexes could interact in a groove binding manner with DNA. Density functional theory (DFT) calculations were employed to support the structural and vibrational studies and to predict the chemical reactivity. Docking simulations were conducted to evaluate their behavior of the synthesized compounds towards DNA (PDB: 1BNA). These results suggested that various elements, including NH groups, imidazole rings, thioetheric sulfur atom and sulfate moieties of ligands and complexes, are involved in groove binding with DNA.

This works describes a new step into the assembly of molecular textiles by the use of covalent templating. To establish a well-founded base and to tackle pre-mature obstacles, expected during the fabrication of the desired 2D-material, we opted to investigate the in-solution synthesis of molecular patches e. g. cut-outs of a textile. A bi-functional cross-shaped monomer was designed, synthesized and was in-detail characterized by means of 1H-NMR and chiro-optical spectroscopy. In addition, x-ray structure crystallography was used to assess the absolute configuration. The monomer was used in an in-solution oligomerization to assemble the molecular patches via imine condensation, which revealed the formation of predominately dimeric patches. The imine-oligomer mixtures were further analyzed by reduction and cleaved to investigate the conditions required post mono-layer assembly. All reaction stages were followed by FT-IR and 1H-NMR analysis. Finally, we address the adsorption of the cross-shaped monomer onto a Au(111) surface, via high vacuum electrospray deposition. The subsequent annealing of the interface induced the on-surface imine condensation reaction, leading to unidimensional oligomers co-adsorbed with clusters of cyclic-dimers. Nc-AFM analysis revealed the tridimensional molecular structures, and together with electrospray deposition technique showed to be a promising pathway to investigate potential monomer candidates.

Eight pincer nickel chlorides, [ R C carbene N amido R′2 N amine –Ni–Cl] (R/R′2 = quinolinyl/ n Bu (3a); quinolinyl/Me (3b); quinolinyl/PhCH 2 (3c); (CH 2 ) 4 / n Bu (5a); (CH 2 ) 4 / i Pr (5b); Me 2 / n Bu (5c); Me 2 / i Pr (5d); Me 2 /PhCH 2 (5e)), were obtained.