Two novel two‐dimensional metal–organic frameworks (2D MOFs), 2D‐M2TCPE (M=Co or Ni, TCPE=1,1,2,2‐tetra(4‐carboxylphenyl)ethylene), which are composed of staggered (4,4)‐grid layers based on ...paddlewheel‐shaped dimers, serve as heterogeneous photocatalysts for efficient reduction of CO2 to CO. During the visible‐light‐driven catalysis, these structures undergo in situ exfoliation to form nanosheets, which exhibit excellent stability and improved catalytic activity. The exfoliated 2D‐M2TCPE nanosheets display a high CO evolution rate of 4174 μmol g−1 h−1 and high selectivity of 97.3 % for M=Co and Ni, and thus are superior to most reported MOFs. The performance differences and photocatalytic mechanisms have been studied with theoretical calculations and photoelectric experiments. This study provides new insight for the controllable synthesis of effective crystalline photocatalysts based on structural and morphological coregulation.
As a result of rational structural design and structure‐directed morphology control, two new 2D MOFs underwent photochemically assisted in situ exfoliation to form nanosheets during visible‐light photocatalytic CO2 reduction (see picture). The exfoliated nanosheets displayed a high CO evolution rate and high selectivity for the formation of CO.
A series of zirconium polyphenolate‐decorated‐(metallo)porphyrin metal–organic frameworks (MOFs), ZrPP‐n (n = 1, 2), featuring infinite ZrIV‐oxo chains linked via polyphenolate groups on four ...peripheries of eclipse‐arranged porphyrin macrocycles, are successfully constructed through a top–down process from simulation to synthesis. These are the unusual examples of Zr‐MOFs (or MOFs in general) based on phenolic porphyrins, instead of commonly known carboxylate‐based types. Representative ZrPP‐1 not only exhibits strong acid resistance (pH = 1, HCl) but also remains intact even when immersed in saturated NaOH solution (≈20 m), an exceptionally large range of pH resistance among MOFs. The metallation at the porphyrin core gives rise to materials with enhanced sorption and catalytic properties. In particular, ZrPP‐1‐Co, with precise and uniform distribution of active centers, exhibits not only high CO2 trapping capability (≈90 cm3 g−1 at 1 atm, 273 K, among the highest in Zr‐MOFs) but also high photocatalytic activity for reduction of CO2 into CO (≈14 mmol g−1 h−1) and high selectivity over CH4 (>96.4%) without any cocatalyst under visible‐light irradiation (λ > 420 nm). Given the strong chemical resistance under extreme alkali conditions, these catalysts can be recycled without appreciable loss of activity. The possible mechanism for photocatalytic reduction of CO2‐to‐CO over ZrPP‐1‐Co is also proposed.
Top–down fabrication of robust and porous materials based on infinite ZrIV‐polyphenolate chains linked via eclipsed‐arranged porphyrin macrocycles is presented. Among them, ZrPP‐1 retains its framework integrity when immersed in saturated NaOH solution as long as 1 week. Moreover, metallation at the porphyrin core gives rise to materials with enhanced CO2 trapping capability and high visible‐light‐driven CO2‐to‐CO photoreduction activity.
Synergetic optical resolution and chiral amplification of tetrahedral Ti4L6 cages by enantiopure coordination cations have been realized in this work. Anionic ΔΔΔΔ-Ti4L6 and ΛΛΛΛ-Ti4L6 cages (L = ...embonate) have been completely resolved by enantiopure Λ-Mn(1R,2R-DCH)3 and Δ-Mn(1S,2S-DCH)3 cations, respectively. Accordingly, two homochiral compounds (PTC-108(Δ) and PTC-108(Λ)) with three-dimensional supramolecular architectures were formed, containing larger diamondoid cages. Such an unusual resolution process clearly shows the stepwise transfer of homochirality from an enantiopure molecule to a resolved hydrogen-bonding aggregation and a final homochiral framework. Moreover, the separated homochiral Ti4L6 cage presents enantioselective recognition toward chiral organic and pharmaceutical molecules. This work opens a novel resolution-dependent homochiral framework construction approach, and it also takes the homochiral tetrahedral Ti4L6 cages with high solubility and stability into promising enantioselective application.
Metal–organic frameworks (MOFs) are powerful toolkits to directly correlate structure–function relationships due to their well-defined structures. In this work, ...5,15-di(3,4,5-trihydroxyphenyl)porphyrin (DTPP) and 5,10,15,20-tetra(3,4,5-trihydroxyphenyl)porphyrin (TTPP) are reacted with zirconium ions to afford two MOFs (Zr-DTPP and Zr-TTPP) with acid and base tolerance in the pH range of 1.0–14.0. Powder X-ray diffraction investigation combined with Rietveld refinement reveals the J-aggregated porphyrin building blocks confined by benzene-1,2,3-trisolate-zirconium chains in the newly prepared Zr-DTPP. Electron spin-resonance, singlet-oxygen determination, and sulfides oxidation experiments demonstrate a much better singlet-oxygen evolution of J-aggregated Zr-DTPP than that of unaggregated Zr-TTPP reported previously, in good contrast to the weaker photocatalytic capability disclosed for DTPP than that for TTPP in solution, consummating the theory of photosensitizer J-aggregation in boosting heterogeneous photoinduced singlet-oxygen generation.
Hydrothermal reactions of lanthanide(III) oxide with copper sulfate or copper nitrate and pyrazole-3,5-dicarboxylic acid (H3PDC) lead to two families of heterometallic Ln–Cu coordination polymers, ...Ln2Cu(PDC)2(SO4)(H2O)6n·nH2O (Ln = Dy for 1, Ho for 2, Er for 3) and Ln2Cu(PDC)2(HPDC)(H2O)4n·2nH2O (Ln = Dy for 4, Ho for 5, Er for 6), which are based on the same building units, viz., metalloligands of LnCu(PDC)2. Compounds 1–3 are isostructural, constructed from the similar double-stranded ribbons which can also be described as ladder-typed chains; while isomorphic 4–6 consist of 2D corrugated sheets which can be simplified as distorted trigonal lattices as well. The magnetic measurements indicate that 1–3 exhibit hidden magnetic effect, whereas 4–6 show evident ferromagnetic coupling with a bit of zero-field relaxation. Such magnetic differences can be attributed to the structural variations, viz. configuration dimensionality of the magnetic units.
Interconnection of heterometallic moieties Ln2Cu afforded 1D ladder-like chain (in the presence of the secondary linker, SO42-) and 2D distorted trigonal lattice (without SO42-), both of which exhibited significantly different magnetic properties. Display omitted
•Two families of heterometallic coordination materials, based on the same Ln2Cu building moieties, have two different structures of different dimensions.•Compounds 1–3 have 1D ladder-like chain (in the presence of SO42-), while compounds 4–6 have 2D distorted trigonal lattice (without SO42-).•Such structural variations result in drastic changes in their magnetic properties (ferromagnetic coupling capacity is also augmented along with the increase in the structure dimension).
CdS nanoclusters of four different sizes were integrated with ruthenium‐complex dyes. The cluster–dye crystalline composites, Cd4(SPh)10Ru(bpy)3, Cd8S(SPh)16Ru(bpy)3, ...Cd8S(SPh)13⋅Cl⋅(CH3OCS2)2Ru(phen)3, Cd17S4(SPh)28Ru(bpy)3, and Cd32S14(SPh)40Ru(phen)32 (phen=1,10‐phenanthroline and bpy=bipyridine), show intense absorption in the visible‐light region. They also exhibit size‐dependent photocurrent responses under the illumination of visible light. The photocurrent increases with increased cluster size. The dyes also have significant influence on the photocurrent generation of the composite.
A family of ruthenium‐complex, dye‐organized, CdS, tetrahedral clusters of various sizes was synthesized and characterized. The composite materials contain nanoclusters with precisely defined sizes and exhibit size‐dependent photocurrent responses. The photocurrent responses can also be tuned through inter‐cluster connectivity and the type of dye molecule used (see figure).
Two novel types of lithium clusters, Li4 tetramer and Li2 dimer, have been created as the building blocks of MOFs. The assembly of such unprecedented clusters with two types of tricarboxylate ligands ...leads to two highly open frameworks, one of which exhibits a very high CO2 uptake capacity among Li-based MOFs. The work reveals the interesting and unprecedented structural chemistry of lithium ions.
Hydrothermal reactions of N-piperidinomethane-1-phosphonic acid (H2pmp) and oxalate anion with trivalent rare earth metal ions yielded 13 rare earth oxalatophosphonates with three closely related ...structural types, ranging from two-dimensional (2D) networks to three-dimensional (3D) frameworks. They are formulated as Ln3(Hpmp)3(C2O4)2(H2O)5(ClO4)2·9H2O Ln = Gd (1), Eu (2), Tb(3), type I structure, Ln2(Hpmp)(C2O4)2.5(H2O)3·H2O Ln = Gd (5), Sm (6), Eu (7), Tb (8), Dy (9), Ho (10), Er (11), Yb (12), Y (13), type II structure, and Gd3(Hpmp)(C2O4)4(H2O)6·5H2O (4), type III structure. Their structures were characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), infrared (IR) spectroscopy, elemental analysis (EA), and thermogravimetric analysis (TGA), except that the structures of compounds 2 and 3 were confirmed by PXRD, IR, and EA. The effects of reaction conditions including pH value, reaction temperature, counterion, and stoichiometry of the starting materials on the structures have been discussed. Furthermore, the solid-state photoluminescence properties of the Eu (2 and 7) and Tb (3 and 8) compounds have been measured at room temperature. The two types of Eu and Tb compounds display intense red and green luminescence emissions, respectively, with lifetimes at the millisecond order.
A nine-connected metal–organic framework NiII 2NiIII(μ3-OH)(IN)3(BDC)1.5·xSolvent (BDC = benzene-1,4-dicarboxylate, IN = isonicotinate) has been prepared and characterized. The application of the ...scale-down chemistry through the use of the short and inexpensive BDC and IN ligands leads to a smaller pore size and lower surface area but little compromise in H2 sorption properties. The compound exhibits a high CO2 uptake of 73.1 cm3 g–1 (273 K and 1 atm) despite its moderate Langmuir and BET surface areas (888.3 and 571.0 m2 g–1, respectively). Its H2 uptake (1.47 wt % at 77 K and 1 atm) is also quite high, comparable to that of many materials with high surface area.
Two isomorphic titanium-doped organotin-oxo aromatic aldoxime clusters, SnTi-1 and SnTi-2, have been successfully synthesized via a solvothermal method. Both clusters have an identical undecameric ...core, consisting of a pentagonal wheel-shaped moiety {Ti5} and two alkylate trimers {Sn3} fused together, and decorated with unsubstituted and methoxy-substituted aldoxime ligands, respectively. They exhibit excellent solubility, chemical stability, and hydrophobicity owing to the existence of peripheral protective shells of alkyl and aromatic groups. The steric hindrance effect of methoxy induces a rearrangement of clusters, altering weak interactions from C–H···π to π···π between cluster molecules, and ultimately modulating the third-order nonlinear optical from saturation absorption to reverse saturation absorption.
Two titanium-doped organotin-oxo-aldoxime clusters were successfully synthesized. The steric hindrance effect of methoxyl induces a significant alteration in the arrangement of clusters, ultimately modulating the third-order nonlinear optical response from saturation absorption to reverse saturation absorption. Display omitted
•Two titanium-doped isomorphic organotin-oxo cluster exhibit excellent solubility, chemical stability, and hydrophobicity.•The intercluster interaction is manipulated by the steric hindrance effect of aldoxime ligands.•Achieving modulation from saturation absorption to reverse saturation absorption.
