The electrocatalytic oxidation of chloride to chlorine is a fundamental and important electrochemical reaction in industry. Herein we report the synthesis of non-stoichiometric silver halide nanoparticles through a novel macrocycle-assisted bulk-to-cluster-to-nano transformation. The acquired positively charged nanoparticles expedite chloride transportation by electrostatic attraction and facilitate the formation of silver polychloride catalytic species on the surface, thus functioning as efficient and selective electrocatalysts for the chlorine evolution reaction (CER) at a very low overpotential and within a wide concentration range of chloride. The formation of uncommon non-stoichiometric nanoparticles prevents the formation of a AgCl precipitate and exposes more coordination unsaturated silver atoms to catalyze CER, finally causing a large enhancement of the atomic catalytic efficiency of silver. This study showcases a promising approach to achieve efficient catalysts from a bottom-up design.

Asymmetric arrangement of metal atoms is crucial for understanding the chirality origin of chiral metal nanoclusters and facilitating the design and development of new chiral catalysts and chiroptical devices. Here, we describe the construction of four asymmetric gold and gold–silver clusters by chirality transfer from diimido ligands. The acquired metal clusters show strong circular dichroism (CD) response with large anisotropy factors of up to 6 × 10–3, larger than the values of most reported chiral gold nanoclusters. Regardless of the same absolute configuration of the applied three diimido ligands, sigmoidal and reverse-sigmoidal arrangements of gold atoms both can be achieved, which resultantly produce an opposite Cotton effect within a specific absorption range. On the basis of the detailed structural characterization via X-ray crystallography and contrast experiments, the chirality contribution of the imido ligand, the asymmetrically arranged metal cluster, and the chiral arrangement of aromatic rings of phosphine ligands have been qualitatively evaluated. Time-dependent DFT calculations reveal that the chiroptical property of the acquired metal clusters is mainly influenced by the asymmetrically arranged metal atoms. Correlation of asymmetric arrangements of metal atoms in clusters with their chiroptical response provides a viable means of fabricating a designable chiral surface of metal nanoclusters and opens a broader prospect for chiral cluster application.

We report herein the efficient synthesis of alkynyl-protected silver nanoclusters in terms of macrocycle-assisted bulk-to-cluster-to-nanoparticle transformation. Different substituted phenylacetylide ligands are applied to stabilize the silver nanoclusters by metal–carbon bonds and meanwhile determine the size of silver nanoclusters.

Three silver cluster complexes were synthesized with carbon network ligands as inner templates, including [(CC)2CC(CC)2]4−, [C6(CC)6]6− and [C6H(CC)5]5−. The resulting clusters 1–3 have been characterized by X-ray crystallography and other techniques. This study showcases a promising methodology to acquire intricate all-carbon units and provides a platform to investigate their chemistry.

Chirality-specific growth of single-walled carbon nanotubes (SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise silver cluster complex [Ag15{1,3,5–(C≡C)3–C6H3}2(Py[8])3–(CF3SO3)3] (CF3SO3)6 (Py[8] is abbreviation for octamethylazacalix[8] pyridine) as a catalyst precursor. The diameters of most acquired SWNTs distributed in the range of 1.2–1.4 nm, which is suitable for making high performance field-effect transistors. The high quality of the obtained SWNTs was evidenced by Raman spectroscopy and electrical measurements. Successful growth of high quality SWNTs in this study foresees that rational design of metal-organic complexes as growth catalysts can open up a new avenue for the controllable synthesis of SWNTs.

We report herein a new nanoparticlization process for the bulk-to-nano transformation of Ag2S by incorporating both top-down and bottom-up approaches. Bulk Ag2S was dissolved in solution with the assistance of a macrocyclic ligand, hexamethylazacalix[6]pyridine (Py[6]), to produce polynuclear silver sulfide cluster aggregates. All Ag–S cluster aggregates obtained in three crystalline complexes were protected by Py[6] macrocycles. Removing the protective Py[6] macrocycles by protonation led to the generation of unconventional Ag–S nanoparticles with a large energy gap. Theoretical calculations by a hybrid DFT method demonstrated that the silver sulfide clusters with high Ag/S ratio exhibited more localized HOMO–LUMO orbitals, which consequently enlarged their band gap energies. These experimental and theoretical studies broaden our understanding of the fabrication of nanomaterials by virtue of the advantages of both bottom-up and top-down methods and meanwhile provide a viable means of adjusting the band gap of binary nanomaterials independent of their size.

We report herein the synthesis of two different silver clusters of aryl- and alkyl-thiolates. These two cluster complexes exhibited biased C–S bond cleavage reaction rates upon removing protective hexamethylazacalix[6]pyridine (Py[6]) ligands, which was applied in the fabrication of silver sulfide nanoclusters with variable and controllable sizes.

The synthesis, characterization, and reactivity of the monoaryl–Ni(II) compound 2 and the diaryl–Ni(II) compound 4 formed through the direct electrophilic metalation of two macrocyclic azacalix[m]arene[n]pyridine ligands are described. Compound 4 was much more stable in protic solvents and acids than the monoaryl–Ni(II) compound 2. Moreover, 2 can react with a variety of nucleophiles, resulting in the formation of C–C, C–O, C–Br, and C–N bonds. In contrast, compound 4 exhibited very inert reactivity upon reaction with a large numberof nucleophiles. Interestingly, compound 2 was also capable of reacting with several less bulky alkyl halides to form new C–C bonds, while the same procedure is inapplicable to 4. The study reported in this work provides a thorough investigation on the reactivity of aryl–Ni(II) species that should facilitate comprehension of the detailed mechanism of nickel-catalyzed C–H functionalization.

We report herein the designed synthesis of four silver(I)- or gold(I)-bridged flexible metalla-macrocycles (MMCs) and their distinct performance in the surface modification of gold nanoparticles (AuNPs). The resulting gold(I)-MMCs-modified AuNPs were found to be resistant to pH variation and capable of binding with metal ions.

We report herein the occurrence of a positive homotropic allosteric binding effect of two macrocyclic azacalixpyridines. This effect was firstly found to be crucial in the formation and stabilization of ultra-small silver nanoparticles.

A dual-templated approach for the controllable synthesis of metal cluster complexes is described. By using an acetylide-containing anion with specific geometry as a central template and a macrocyclic coordinative compound as a peripheral one, two multinuclear silver-acetylide cluster-encapsulated supramolecular boxes were synthesized.

An unprecedented polynuclear metal cluster-pillared triangular prism was built by a macrocycle-directing strategy. Discrete architectures of three silver cluster-involved metallosupramolecules were characterized by single crystal X-ray crystallography and spectroscopy studies.

We report herein the synthesis of a new heteracalixaromatic compound, tetramethylazacalix[4]pyrazine (TAPz), and its coordination self-assemblies with metal and metal cluster centers. Structural characterization of TAPz has shown that its conformation is fluxional in solution but exhibits a dominant 1,3-alternate configuration in the crystalline solid state, wherein its convergent chelating coordination sites are orthogonal to the 120°-angled bridging sites, thus forming a unique multimodal ligand. Compound TAPz reacting with silver, zinc metal centers, and CuxIx cluster centers leads to the construction of diverse coordination network structures in 1–5 including honeycomb, Kagomé, α-quartz, and cavity-involved two-dimensional layers. The structural diversity of these network structures is conducted by different combination modes between the chelation bonding sites of TAPz and metal or metal cluster centers. This system may afford deeper insight on the fantastic use of macrocyclic compounds on the designed synthesis of coordination network structures through the proper arrangement of their coordination sites.

Three internally 1,3-arylene-bridged azacalix[6]aromatics 1–3 were synthesized by the Pd-catalyzed macrocyclic fragment coupling reaction between a stellated dibrominated pentamer and N2,N6-dimethylpyridine-2,6-diamine or N1,N3-dimethylbenzene-1,3-diamine. Single-crystal X-ray analysis revealed that these bimacrocyclic compounds all adopt a triply pillared groove-shaped conformation, conceptually being derived from the fusion of two 1,3-alternate macrocycles. Four host/metal discrete complexes of the all-pyridine host 1, {Co(1)(CH3OH)2}(CoCl4)·3(CH3OH), {Ni(1)(CH3OH)2}(NiCl4), {Ni(1)(CH3OH)2}(ClO4)2·CH3OH and {Cd2(1)(CH3CN)4(H2O)4}(ClO4)4, have been structurally characterized by X-ray crystallographic analysis, exploring two different metal binding modes. The metal complexation property of the host 1 in solution was then investigated by the UV-vis and NMR titration. With variation of the radii of the tested metal ions (Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Hg2+), the host 1 can trap one or two metal ions via four different modes by using its two coordination cavities or two marginal pyridine rings. Such metal binding diversity of internally bridged heteracalixaromatics spotlights their potential applications in metal ion transport, ion channel, and metallo-enzyme mimics.

We report herein the synthesis of a new metal cluster-encapsulated supramolecular capsule, [(C≡C)@Ag5–6@(Py6)2](CF3SO3)3–4 (3, Py6 = azacalix[6]pyridine), by use of a bowl-shaped macrocyclic ligand Py6. The multinuclear silver carbide cluster aggregate in 3 is encapsulated by two Py6 ligands through both metal–ligand coordination and cation−π interactions, spotlighting a new synthetic strategy for supramolecular capsules.

The designed synthesis and structural characterization of two metal cluster-centered metallosupramolecular architectures are reported. In complex [(CF3SO3)Ag4(tBuC≡C)(Py8)](CF3SO3)2 (1) and [(CF3SO3)Ag4{C≡C–(m-C6H4)–C≡C–(m-C6H4)–C≡C–(m-C6H4)–C≡C}Ag4(CF3SO3)(Py8)2](CF3SO3)4 (2), organic acetylide ligands are utilized to induce the formation of polynuclear silver aggregates, which are encapsulated into the central cavity of the neutral macrocyclic compound azacalix[8]pyridine (Py8). The tetrasilver cluster centered [2]- and [3]-pseudo-rotaxane structures are obtained and fully characterized by X-ray crystallography, ESI mass spectrometry, and 1H NMR spectroscopy.

The coordination self-assembly between the macrocyclic ligand tetraazacalix[4]pyrimidine (TAPM) with cubane-like copper halides (Cu4X4) produced five coordination polymers 1–5 {Cu4Br4−mIm(TAPM)}n (m=0 (1), 1 (2), 2 (3), 3 (4) and 4 (5)). X-ray single crystal analysis revealed that the Br:I ratio in the Cu4X4 cores serves as a controlling factor to fine-tune the geometries of Cu4X4 and therefore induce the conformation variation of tetraazacalix[4]pyrimidine. Consequently, two different topological nets, dia and lcs, were successfully constructed based on tetrahedrally coordinated Cu4X4 secondary building units and the flexible macrocyclic quadridentate ligand TAPM. The structure details of 1–5 as porous materials are analyzed, which shows a solvent accessible volume within the range of 27−35%. Compounds 1–5 exhibit luminescence properties with the peak maximum at around 476−488 nm.Graphical AbstractFive luminescent coordination polymers 1–5 were obtained via the reaction of tetrahedral Cu4Br4−mIm SBUs and a flexible macrocyclic ligand tetraazacalix[4] pyrimidine (TAPM), wherein the Br/I ratio serves as a controlling factor to fine-tune the geometries of Cu4Br4−mIm and induce the conformation variation of TAPM, thus constructing two different dia and lcs topological nets.Research Highlights► The ratio of Br/I in the Cu4X4 cores fine-tunes the geometries of Cu4X4. ► Variation of Cu4X4 induces the conformation change of the ligand TAPM. ► Two different coordination polymeric structures were successfully constructed. ► The five coordination polymers show good luminescent properties.

Chirality-specific growth of single-walled carbon nanotubes (SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise silver cluster complex [Ag15{1,3,5–(C≡C)3–C6H3}2(Py[8])3–(CF3SO3)3] (CF3SO3)6 (Py[8] is abbreviation for octamethylazacalix[8] pyridine) as a catalyst precursor. The diameters of most acquired SWNTs distributed in the range of 1.2–1.4 nm, which is suitable for making high performance field-effect transistors. The high quality of the obtained SWNTs was evidenced by Raman spectroscopy and electrical measurements. Successful growth of high quality SWNTs in this study foresees that rational design of metal-organic complexes as growth catalysts can open up a new avenue for the controllable synthesis of SWNTs.

We report herein the synthesis of two different silver clusters of aryl- and alkyl-thiolates. These two cluster complexes exhibited biased C–S bond cleavage reaction rates upon removing protective hexamethylazacalix[6]pyridine (Py[6]) ligands, which was applied in the fabrication of silver sulfide nanoclusters with variable and controllable sizes.

We report herein the designed synthesis of four silver(I)- or gold(I)-bridged flexible metalla-macrocycles (MMCs) and their distinct performance in the surface modification of gold nanoparticles (AuNPs). The resulting gold(I)-MMCs-modified AuNPs were found to be resistant to pH variation and capable of binding with metal ions.

We report herein the efficient synthesis of alkynyl-protected silver nanoclusters in terms of macrocycle-assisted bulk-to-cluster-to-nanoparticle transformation. Different substituted phenylacetylide ligands are applied to stabilize the silver nanoclusters by metal–carbon bonds and meanwhile determine the size of silver nanoclusters.

Three silver cluster complexes were synthesized with carbon network ligands as inner templates, including [(CC)2CC(CC)2]4−, [C6(CC)6]6− and [C6H(CC)5]5−. The resulting clusters 1–3 have been characterized by X-ray crystallography and other techniques. This study showcases a promising methodology to acquire intricate all-carbon units and provides a platform to investigate their chemistry.

A dual-templated approach for the controllable synthesis of metal cluster complexes is described. By using an acetylide-containing anion with specific geometry as a central template and a macrocyclic coordinative compound as a peripheral one, two multinuclear silver-acetylide cluster-encapsulated supramolecular boxes were synthesized.

An unprecedented polynuclear metal cluster-pillared triangular prism was built by a macrocycle-directing strategy. Discrete architectures of three silver cluster-involved metallosupramolecules were characterized by single crystal X-ray crystallography and spectroscopy studies.

The electrocatalytic oxidation of chloride to chlorine is a fundamental and important electrochemical reaction in industry. Herein we report the synthesis of non-stoichiometric silver halide nanoparticles through a novel macrocycle-assisted bulk-to-cluster-to-nano transformation. The acquired positively charged nanoparticles expedite chloride transportation by electrostatic attraction and facilitate the formation of silver polychloride catalytic species on the surface, thus functioning as efficient and selective electrocatalysts for the chlorine evolution reaction (CER) at a very low overpotential and within a wide concentration range of chloride. The formation of uncommon non-stoichiometric nanoparticles prevents the formation of a AgCl precipitate and exposes more coordination unsaturated silver atoms to catalyze CER, finally causing a large enhancement of the atomic catalytic efficiency of silver. This study showcases a promising approach to achieve efficient catalysts from a bottom-up design.

We report herein a new nanoparticlization process for the bulk-to-nano transformation of Ag2S by incorporating both top-down and bottom-up approaches. Bulk Ag2S was dissolved in solution with the assistance of a macrocyclic ligand, hexamethylazacalix[6]pyridine (Py[6]), to produce polynuclear silver sulfide cluster aggregates. All Ag–S cluster aggregates obtained in three crystalline complexes were protected by Py[6] macrocycles. Removing the protective Py[6] macrocycles by protonation led to the generation of unconventional Ag–S nanoparticles with a large energy gap. Theoretical calculations by a hybrid DFT method demonstrated that the silver sulfide clusters with high Ag/S ratio exhibited more localized HOMO–LUMO orbitals, which consequently enlarged their band gap energies. These experimental and theoretical studies broaden our understanding of the fabrication of nanomaterials by virtue of the advantages of both bottom-up and top-down methods and meanwhile provide a viable means of adjusting the band gap of binary nanomaterials independent of their size.

We report herein the occurrence of a positive homotropic allosteric binding effect of two macrocyclic azacalixpyridines. This effect was firstly found to be crucial in the formation and stabilization of ultra-small silver nanoparticles.