RESUMEN
Room-temperature phosphorescent (RTP) materials play a crucial role in optical anticounterfeiting science and information security technologies. Ionically bonded organic metal halides have emerged as promising RTP material systems due to their excellent self-assembly and unique photophysical property, but their intrinsic instability largely hinders their advanced practical applications. Herein, we employ a coordination-driven synthetic strategy utilizing organocarboxylates for the synthesis of two isostructural layered lead halide frameworks. The frameworks adopt a new mixed-layered topology, consisting of alternating [Pb10X9]11+ (X = Cl-/Br-) layers and [Pb6XO3]11+ (X = Cl-/Br-) layers that are coordinatively sandwiched by organocarboxylate layers. The frameworks exhibit long-lived green afterglow emission with the long lifetime of up to 45.89 ms and the photoluminescence quantum yield (PLQY) of up to 43.13%. The Pb2+-carboxylate coordination accelerates the metal-to-ligand charge transfer from the light-harvesting lead halide layers to the phosphorescent organic component, promoting efficient spin-orbit coupling and intersystem crossing. Moreover, the coordination networks exhibit good structural robustness under ambient conditions for at least 12 months, as well as stability in boiling water, acidic and basic aqueous environments. The highly efficient afterglow and high structural integrity enable multiple anticounterfeiting applications across diverse chemical environments.
RESUMEN
Highly connected molecular building blocks (MBBs) have been demonstrated to play a crucial role in reticular chemistry, particularly in predicting the topologies of metal-organic frameworks. Metal phosphonate clusters exhibit considerable advantages in constructing high-connectivity MBBs, owing to the multiple coordination modes offered by phosphonic ligands. Herein, four metal (M = CoII, MnII) phosphonocarboxylate frameworks (CoPCF-1,2 and MnPCF-1,2) were successfully prepared under solvothermal conditions by utilizing the phosphonocarboxylic ligand, 4'-phosphonobiphenyl-3,5-dicarboxylic acid (H4pbpdc), and their structural characterization was performed using single-crystal X-ray diffraction (SCXRD). The structures feature a duodenary nuclear M12(µ3-OH)2(CO2)12(PO3)6(DMF)6/(CH3COO)4.5 cluster, bearing resemblance to the well-known Wells-Dawson ion from polyoxometallate chemistry. It is the first time a Wells-Dawson type cage has served as an 18-connected molecular building block, forming two kinds of porous metal phosphonocarboxylate frameworks with novel (3,18)-connected gez and gea topologies. Their permanent porosities were confirmed through N2 adsorption studies. Notably, the MBB Co12 cluster-based CoPCF-1 shows a loss and recovery process of µ3-OH through single-crystal-to-single-crystal (SCSC) transformation. The magnetic properties of the four compounds exhibit antiferromagnetic behavior.
RESUMEN
A 3D hydrogen-bonded metal-organic framework, [Cu(apc)2]n (TJU-Dan-5, Hapc = 2-aminopyrimidine-5-carboxylic acid), was synthesized via a solvothermal reaction. The activated TJU-Dan-5 with permanent porosity exhibits a moderate uptake of 1.52 wt% of hydrogen gas at 77 K. The appropriate BET surface areas and decoration of the internal polar pore surfaces with groups that form extensive hydrogen bonds offer a more favorable environment for selective C2H6 adsorption, with a predicted selectivity for C2H6/CH4 of around 101 in C2H6/CH4 (5:95, v/v) mixtures at 273 K under 100 kPa. The molecular model calculation demonstrates a C-H···π interaction and a van der Waals host-guest interaction of C2H6 with the pore walls. This work provides a strategy for the construction of 3D hydrogen-bonded MOFs, which may have great potential in the purification of natural gas.
RESUMEN
Organolead halide hybrids have many promising attributes for photocatalysis, e.g. tunable bandgaps and excellent carrier transport, but their instability constraints render them vulnerable to polar molecules and limit their photocatalysis in moisture. Herein, we report the construction of metal-organic frameworks based on [Pb2X]3+ (X = Br-/I-) chains as secondary building units and 2-amino-terephthalate as organic linkers, and extend their applications in photocatalytic CO2 reduction with water vapor as the reductant. Hall effect measurement and ultrafast transient absorption spectroscopy demonstrate the bromo/iodo-bridged frameworks have substantially enhanced photocarrier transport, which results in photocatalytic performances superior to conventional metal-oxo metal-organic frameworks. Moreover, in contrast to lead perovskites, the [Pb2X]3+-based frameworks have accessible porosity and high moisture stability for gas-phase photocatalytic reaction between CO2 and H2O. This work significantly advances the excellent carrier transport of lead perovskites into the field of metal-organic frameworks.
RESUMEN
To enhance light absorption in the visible region for the utilization of sunlight, eight mixed-valence polynuclear CuI/CuII clusters have been synthesized for evaluating their photothermal conversion performance. They are fabricated considering the ligand's electron density distribution inhomogeneity using 1,2,3-triazole (3N) or tetrazole (4N) and different mono-phosphine ligands. We report here the synthesis, crystal structure, characterization, optical properties, and photothermal conversion performance of these clusters. X-ray crystal structures reveal that those pentanuclear clusters are neutral clusters with octahedrally-coordinated copper(II) ion being surrounded by four tetrahedrally coordinated copper(I) ions. Interestingly, with the introduction of the mixed-valence centers, these compounds show additional light absorption centers in 350-600 nm via the IVCT transition mechanism, compared with our previously reported Cu(II) compounds. These clusters show excellent photothermal conversion performance, with an average equilibrium temperature (â¼60 °C) and a temperature increment (â¼40 °C), which are also superior to Cu(II) complexes (the average equilibrium temperature â¼55 °C). This work proves that it is possible to design and prepare new polynuclear mixed-valence CuI/CuII clusters for achieving high-performance photothermal conversion materials.
RESUMEN
Deep-ultraviolet (deep-UV) nonlinear optical (NLO) crystals are key materials in creating tunable deep-UV lasers for frequency conversion technology. However, practical application of the sole usable crystal, KBe2 BO3 F2 , has been hindered by the high toxicity of beryllium and its layering tendency in crystal growth. Herein, we report a beryllium-free deep-UV NLO material NaSr3 (OH)(B9 O16 )[B(OH)4 ] (NSBOH), synthesized by a covalent bond modification strategy under hydrothermal conditions. Moisture-stable NSBOH exhibits strong second-harmonic generation (SHG) at 1064â nm (3.3 × KH2 PO4 ) and 532â nm (0.55 × ß-BaB2 O4 ), both amongst the largest powder SHG responses for a deep-UV borate, with good phase-matchability and a short wavelength cutoff edge (below 190â nm). NSBOH possesses a 3D covalent anionic [B9 O19 ]∞ honeycomb-like framework with no layering. The Sr2+ and Na+ ions, residing in the cavities of the anionic framework, act as templates for the assembly and favorable alignment of NLO-active groups, resulting in an optimal balance between strong SHG activities and wide UV transparency. These merits indicate NSBOH is a very attractive candidate for deep-UV NLO applications.
RESUMEN
A series of isostructural lanthanide phosphonocarboxylate frameworks {(H3O)3[Ln7(pbpdc)6(DMF)4(H2O)3]·4H2O}n (named LnPCF, Ln = Tb, Eu and Gd, H4pbpdc = 4'-phosphono-[1,1'-biphenyl]-3,5-dicarboxylic acid) were solvothermally synthesized and characterized by the single crystal X-ray diffraction technique. By combining lanthanide cations with a phosphonocarboxylate ligand, a heptametallic lanthanide phosphonate [Ln7(PO3)6(COO)12] core was obtained. This core exhibited as a rare highly 18-connected node and was linked by the 3-connected pbpdc4- ligand, forming a (3,18)-connected framework with a novel topology of {43}6{438·676·839}. This LnPCF structure is an ideal platform for accommodating various lanthanide ions. The TbPCF and EuPCF show efficient luminescence emission due to the "antenna effect" and incorporating Gd3+ into the TbPCF results in a drastic luminescence enhancement. Fine colour tuning between green and red can be easily achieved in bimetallic TbxGd1-xPCFs. More significantly, upon combining a few percent of Nd3+ and Gd3+ with Tb3+, the resulting trimetallic Tb0.4Gd0.5Nd0.1PCF shows dual emissions of both visible and near-infrared light.
RESUMEN
Nitrogen doped Mg2TiO4 spinel, i.e. Mg2TiO4-xNy, has been synthesized and investigated as a photocatalyst for antibacterial activity. Mg2TiO4-xNy demonstrates superior photocatalytic activity for E. coli disinfection under visible light illumination (λ ≥ 400 nm). Complete disinfection of E. coli at a bacterial cell density of 1.0 × 107 CFU mL-1 can be achieved within merely 60 min. Mg2TiO4-xNy is capable of generating superoxide radicals (â¢O2 -) under visible light illumination which are the reactive oxygen species (ROSs) for bacteria disinfection. DFT calculations have verified the importance of nitrogen dopants in improving the visible light sensitivity of Mg2TiO4-xNy. The facile synthesis, low cost, good biocompatibility and high disinfection activity of Mg2TiO4-xNy warrant promising applications in the field of water purification and antibacterial products.
RESUMEN
Electropolymerisation of the novel polyoxotitanate (POT) hexamer [Ti(µ3-O)(OiPr)(TA)]6 (TA = thiophene-3-acetate) with 3,4-ethylenedioxythiophene (EDOT) gives films of hybrid conjugated copolymer, Poly-(EDOT-POT)s, the morphologies of which are, uniquely, influenced by the electropolymerisation potential. Nanoporous Poly-(EDOT-POT)-1 is a fast-ion electrode material and has improved electrochromic properties and significantly higher capacitance than that of the parent poly(3,4-ethylenedioxythiophene) (PEDOT).
RESUMEN
Fluorination of 2-aminopyridines and pyridin-2(1 H)-ones in the presence of Selectfluor, water, and chloroform under mild conditions has been realized. This method gives fluorinated pyridines in good to high yields with high regioselectivities. The electron-deficient pyridine system is activated by an amino or hydroxyl group at C2. The regioselectivity of the fluorination reaction is strongly dependent upon the substituent pattern in the 2-aminopyridine or pyridin-2(1 H)-one. The transformation of the 3-fluoro-substituted pyridine derivative into fluorinated zolimidine was achieved as well.
RESUMEN
The acylation reaction of BN-arenes has been studied using BN-arene and acyl chloride in good to excellent yields, which led to the first synthesis of indanone BN-analogue. The BN-aromatic ketone products have been characterized by 1H NMR spectroscopy with their molecular structures unambiguously confirmed by X-ray crystallography. The annulation reaction of BN-arenes promoted by AgBF4 occurs in a completely regioselective manner and a mechanism for this transformation is proposed.
RESUMEN
diasteroselective and enantioselective Ir-catalyzed allylic substitutions of 1-substituted 1-fluoro-1-(arenesulfonyl)methylene derivatives are presented, which afford the fluorinated allyl products with two chirality centers. The steric demand of 1-substituted 1-fluoro-1-(arenesulfonyl)methylene derivatives and allylic substrates has a great influence on the dr values of these reactions. The transformation of the branched allyl product into the fluorinated 3,4-dihydro-2H-pyrrole 1-oxide was discussed, as well.
RESUMEN
An indium phosphonocarboxylate framework, {H3O[In(pbpdc)]·3H2O}n (InPCF-1) (pbpdc = 4'-phosphonobiphenyl-3,5-dicarboxylate), was hydrothermally synthesized. The structure of InPCF-1 features the inorganic chains as rod-shaped second building units. The rod-packing arrangement results in a three-dimensional (3-D) framework with a novel (3,4,5)-connected net. Studies of the gas adsorption, and thermal and chemical stability of InPCF-1 demonstrated its adsorption capacity for CO2, selective separation of CO2 over O2 and N2, high thermal stability, and a remarkable chemical resistance to boiling water, ethyl alcohol, and methylbenzene. Importantly, InPCF-1 shows a selective and sensitive response to Cu(2+) ions. It also serves as a sensor for methylviologen.
RESUMEN
In the crystal of the title compound, C(15)H(34)N(+)·CH(3)SO(4) (-), the cations and anions are joined together via strong N-Hâ¯O hydrogen bonds into layers parallel to (001).
RESUMEN
In the title compound, C(13)H(30)N(+)·Cl(-)·H(2)O, the C(13)H(27) alkyl chain is in an all-trans conformation. In the crystal, inter-molecular N-Hâ¯Cl, N-Hâ¯O and O-Hâ¯Cl hydrogen bonds connect the components into layers parallel to (010), with the alkyl chains oriented approximately perpendicular to these layers.
RESUMEN
In the title compound, C(12)H(28)N(+)·Br(-)·H(2)O, the ionic pairs formed by n-dodecyl-ammonium cations and bromide anions are arranged into thick layers; these layers are linked in a nearly perpendicular fashion [the angle between the layers is 85.84â (5)°] by hydrogen-bonding inter-actions involving the water mol-ecules. The methyl-ene part of the alkyl chain in the cation adopts an all-trans conformation. In the crystal structure, mol-ecules are linked by inter-molecular N-Hâ¯Br, O-Hâ¯Br and N-Hâ¯O hydrogen bonds.
RESUMEN
2-Aminopyridinium benzoate was synthesized. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the compound. The lattice potential energy of the title compound was calculated to be UPOT = 284.297 kJ mol-1. Low-temperature heat capacities of the compound were measured by a precision automatic adiabatic calorimeter over the temperature range from 78 K to 365 K. A polynomial equation of heat capacities against the temperature in the region of 78 K to 365 K was fitted by a least square method. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K. According to the synthesis reaction, the standard molar enthalpies of dissolution for the reactants and product in the selected solvent were measured by an isoperibol solution-reaction calorimeter, respectively. Accordingly, the enthalpy change of the synthesis reaction was calculated to be ΔrHom = -(20.016 ± 0.182) kJ mol-1. Finally, the standard molar enthalpy of formation of 2-aminopyridinium benzoate was determined to be ΔfHom = - (365.416 ± 0.961) kJ mol-1 in accordance with Hess law.
