Hierarchical chiral MOFs with the induced chirality of AIE ligands exhibiting non-reciprocal CPL.

Two pairs of chiral MOFs with hierarchical chiral structures were constructed through assembly of achiral AIE-type multidentate linkers and chiral camphoric acid. Non-reciprocal circularly polarized luminescence (CPL) can be observed on the macroscopic due to the coexistence of optical anisotropic and chiroptical nature. This study provides a new perspective to recognize and construct chiral crystalline materials.

Stepwise assembly and reversible structural transformation of ligated titanium coated bismuth-oxo cores: shell morphology engineering for enhanced chemical fixation of CO2.

Herein, we report the stepwise assembly and reversible transformation of atomically precise ligated titanium coated bismuth-oxide core nanostructures. The soluble and stable Bi38O45@Ti6-oxo clusters with weakly coordinated surface salicylate ligands were first prepared as precursors. Owing to the high surface reactivity of the Bi38O45 inner core, its shell composition and morphology could be systemically modified by assembly with various Ti ions and auxiliary ligands (L), especially those with different flexibility, bridging ability and steric hindrance. As a result, a series of new core-shell Bi38O44/45@Ti x L-oxo (x = 14, 16, 18 or 20) clusters containing gradually increasing shell Ti atoms were successfully synthesized. Among them, the Bi38Ti20-oxo cluster is the largest one in the family of heterometallic Bi/Ti-oxo clusters to date. In addition, the sensitized titanium outer shell can effectively improve the photocurrent response under visible light irradiation. More remarkably, the obtained core-shell Bi38O44/45@Ti x L-oxo clusters can serve as stable and efficient catalysts for CO2 cycloaddition with epoxides under ambient conditions, whose activity was significantly influenced by the outer ligated titanium shell structure. This work provides a new insight into the construction of atomically precise heterometallic core-shell nanostructures and also an interesting shell engineering strategy for tuning their physicochemical properties.

Heterometallic Ag2Ti10 and Ag4Ti8-oxo clusters with different silver doping models: synthesis, structure, and theoretical studies.

Two heterometal-oxo Ag2Ti10 (PTC-221) and Ag4Ti8 (PTC-222) clusters were successfully synthesized and characterized, with the doped Ag atoms surrounded by the Ti-O core and exposed to the cluster surface, respectively. Density functional theory (DFT) calculations were carried out to study the electronic structures of PTC-221 and PTC-222, including the frontier orbitals and partial density of states (PDOS). The solid-state UV-vis absorption spectra of PTC-221 and PTC-222 were also recorded. Interestingly, PTC-221 shows intense visible light absorption with an absorption edge around 590 nm and exhibits good photocurrent response in the visible region.

Synergistic ligand effect for the construction of titanium-oxo clusters with planar chirality and high solution stability.

A synergistic effect between dimethylglyoxime (to stabilize the Ti-O ribbon) and nonlinear dicarboxylate ligands (to bend the Ti-O ribbon) has been developed to form a series of planar chiral titanium-oxo clusters with high solution stability. The charality of the obtained clusters has been studied by X-ray structural and CD spectroscopy analysis.

Ligand-directed assembly engineering of trapezoidal {Ti5} building blocks stabilized by dimethylglyoxime.

Through ligand-directed assembly of trapezoidal {Ti5} building blocks stabilized by dimethylglyoxime, eight titanium-oxo molecular clusters with a sandwich or square planar type structures were successfully constructed, including the first success on the combination of porphyrin and titanium-oxo clusters.

Construction of molecular rectangles with titanium-oxo clusters and rigid aromatic carboxylate ligands.

Four rectangular molecular architectures have been successfully constructed using {Ti5O7} clusters as inorganic vertical edges and bridging aromatic carboxylates as horizontal edges. The introduced organic ligands show a strong influence on the light absorption behaviors of the obtained hybrid complexes.

Synthesis of an Enantipure Tetrazole-Based Homochiral CuI,II-MOF for Enantioselective Separation.

An enantipure (1S)-1-(5-tetrazolyl)ethylamine (5-eatz) ligand was first employed to construct a homochiral porous metal-organic framework, {[CuI2CuII(5-eatz)2(CN-)(H2O)]+[NO3-]}·[DMF] (1), with unusual ligand-unsupported Cu···Cu interactions. Such a compound shows high stability in water and common organic solvents. Remarkably, it has high enantioselectivity toward (R,S)-1-phenylethanol and (R,S)-1-phenylpropanol with enantiomeric excess values of up to 42% and 48%, respectively.

A pillared-layer framework with high uptake and selective sorption of light hydrocarbons.

A new pillared-layer metal-organic framework [Zn2(NH2-BTB)(2-nim)] () was successfully synthesized based on mixed ligands, where binuclear [Zn2(CO2)3](+) cluster-based cationic layers [Zn2(NH2-BTB)](+) (NH2-H3BTB = 1,3,5-(three-benzoic acid)aniline) are connected by 2-nitroimidazoles. Compound shows high uptake and good adsorption selectivities for C3/C1 and C2/C1. Particularly, the C2H2 uptake capacity of is up to 152 cm(3) g(-1) at 273 K and the selectivity for C3H8/CH4 is over 85 at room temperature.

Multiarylpolycarboxylate-mediated hybrid cobalt phosphate frameworks with supramolecular zeolitic topology and unusual I(2)O(2) connectivity.

Two novel organic-inorganic hybrid frameworks containing multiarylpolycarboxylate linkers and cobalt phosphate layers, [H2DABCO]·[Co(HPO4)(bpdc)] (1) and [H2DABCO]3·[Co10(npa)3(PO4)6Cl2] (2), where bpdc = 4,4'-biphenyldicarboxylate, npa = 2,6-naphthalenedicarboxylate, and DABCO = 1,4-diazabicyclo[2.2.2]octane, have been solvothermally synthesized. Compound 1 features a 3D zeolite-like supramolecular network with ABW topology, and compound 2 is a 3D framework structure with unusual I(2)O(2) connectivity.