Metal–metal bonding interactions have been used to generate a number of unique supramolecular assemblies with fascinating functions. We presented here a new class of gold(I)-containing metallosupramolecular cages and cage-built two-dimensional (2-D) arrays of {Au8L2}n (n = 1 or ∞, L = tetrakis-dithiocarbamato-calix[4]arene, TDCC), 1–3, which are constructed from the self-assembly of deep-cavitand calix[4]arene-based supramolecular cages consisting of octanuclear Au(I) motifs. Synchrotron radiation X-ray diffraction structural analyses of 1–3 revealed their quadruple-stranded helicate dimeric cage structure and the presence of 2-D arrays of cages linked together by inter- and intramolecular AuI···AuI interactions. Electronic absorption and emission studies of complexes 1–3 indicated the occurrence of a programmable self-assembly process in a concentration-dependent stepwise manner with the links built via aurophilic interactions. These novel gold(I) supramolecular cages exhibited green phosphorescence and have been shown to serve as highly selective proof-of-concept luminescent sensors toward AgI cation among various competitive transition-metal ions.

By employing di-palladium complexes [(N^N)2Pd2(NO3−)2](NO3−)2 (where N^N = 2,2′-bipyridine, bpy; 4,4′-dimethylbipyridine, dmbpy; 1,10-phenanthroline, phen) as corners and tripyrazole functional ligands (H3L1–H3L5) as linkers, a series of highly-positively-charged tripyrazolate-bridged metallo-cages with different conformations and cavities such as [Pd6L2]6+ (1 or 5, where L = L1 or L5), [Pd10L24]10+ (2a, 2b and 4b, where L = L2 or L4) and [Pd12L4]12+ (3 or 4a, where L = L3 or L4) have been synthesized through a di-metal coordination directed self-assembly with spontaneous deprotonation of the tripyrazole ligands in aqueous solution. These complexes have been fully characterized by 1H and 13C NMR, cold-spray ionization or electron spray ionization mass spectrometry (CSI-MS, ESI-MS) and elemental analysis. Complexes 1, 2a, 2b, 3 and 4 have also been determined by single-crystal X-ray diffraction structural analysis. In the case of complex 3, six PF6− anions were encapsulated within the cavity composed of adjacent di-Pd corners.

•We reported two novel organo-palladium molecular baskets•Construction of [Pd3L3]6+ metallo-macrocycles through self-assembly approach•Encapsulating one giant anion [(C2B9H11)2Co]− in water by 1H NMR titrationTwo [M3L3]6 +-type organo-palladium(II) macrocyclic host molecules, {[(phen)Pd]3(4,7-phen)3}(NO3)6, 1·6NO3−; {[(dtod-phen)Pd]3(4,7-phen)3}(NO3)6, 2·6NO3−, (where M = (4,7-phen)Pd, (dtod-phen)Pd; 4,7-phen = 4,7-phenanthroline (L), phen = 1,10-phenanthroline, dtod-phen = 5,6-di(1′,4′,7′,10′-tetraoxododecanoxy)-1,10-phenanthroline), have been synthesized by metal-directed self-assembly in aqueous solution. These basket-shaped hosts bearing syn, syn, syn orientations and their anion complexes, have been fully characterized by 1H NMR, cold-spray ionization mass spectrometry (CSI-MS) and in the case of basket-shaped host 1*PF6− by X-ray single-crystal diffraction analysis. On the basis of anion binding structure within the cavity of 1, the molecule basket 2 possessing a hydrophobic inner cavity expanded with hydrophilic polyethyleneglycol chains was successfully designed for encapsulating one giant anion [(C2B9H11)2Co]− in water and the host–guest interaction was studied by 1H NMR titration and CSI-MS.The molecular basket with a hydrophobic inner cavity and hydrophilic polyethyleneglycol chains can encapsulate one big anion [(C2B9H11)2Co]− in water (see picture).

By employing dipalladium corners [(bpy)2Pd2(NO3)2](NO3)2 or [(phen)2Pd2(NO3)2](NO3)2 (where bpy = 2,2′-bipyridine and phen = 1,10-phenanthroline) to bridge ferrocene-based dipyrazole ligand (L11) and m-phenylene-based dipyrazole ligands (L2–32–3) in aqueous solution, a series of positively-charged [M4L2]4+ metallomacrocycles were obtained. Their structures were characterized by 1H NMR, electrospray ionization mass spectrometry (ESI-MS), elemental analysis, and single crystal X-ray diffraction analysis for 1·4NO3 ({[(bpy)Pd]4L112}(NO3)4) and 4·4NO3 ({[(phen)Pd]4L222}(NO3)4). In their single crystal structures, NO3− anions are located at the dipalladium corners by C–H⋯O hydrogen bonds. Importantly, the anion-sensing properties of ferrocene functionalized [Pd4Fe2] hetero-metallomacrocycle 1 were investigated in acetonitrile by SWV, CV and NMR analysis, showing promise for Br− sensing.

•Two novel nanosized bipyrazolate-bridged metallo-macrocycles were self-assembled.•Coexisted two metallomacrocycles Pd8 and Pd6 were separated in one-pot reaction.•We discussed the self-assembly mechanism of complex 1a and 1b.Two novel nanosized bipyrazolate-bridged metallo-macrocycles with dipalladium(II,II) corners, {[(bpy)Pd]8L4}(NO3)8 and {[(bpy)Pd]6L3}(NO3)6 [L = 1, 4-di(3′,5′-dimethyl-1H-pyrazolyl-4yl)naphthalene] have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the 1H-bipyrazolyl ligand in aqueous solution. These crown-shaped complexes with deep cavities potentially served as the host to solvent molecules and anions. Such metallo-macrocyclic structures have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, 1H and 13CNMR, high resolution electrospray ionization mass spectrometry, UV–visible spectroscopy, and luminescence spectroscopy.Two novel metallomacrocycles Pd8 and Pd6 coexisted in the same reaction, which self-assembled from bipz ligands and diPd coordination motifs. We selectively separated two supramolecular species by changing the recrystallization conditions in one-pot reaction.

The dimetallic [M2(bpy)2(NO3)2](NO3)2 moieties (M = Pd(II) or Pt(II)) react preferentially at the pyrazolyl end of the pyridyl-pyrazole ligand, giving rise to dimetallic corners. Subsequently, the dimetallic corner building blocks featuring two pyridine donors are coordinated by monometallic [M(bpy)(NO3)2] moieties (M = Pd(II) or Pt(II)) to form homo- or hetero-metallomacrocycles.

Fluorescent carbazole-based dipyrazole ligands (H2L1–4) were employed to coordinate with dipalladium corners ([(phen)2Pd2(NO3)2](NO3)2, [(dmbpy)2Pd2(NO3)2](NO3)2, or [(15-crown-5-phen)2Pd2(NO3)2](NO3)2, where phen = 1,10-phenanthroline and dmbpy = 4,4′-dimethyl-2,2′-bipyridine, in aqueous solution to afford a series of positively charged [M8L4]8+ or [M4L2]4+ multimetallomacrocycles with remarkable water solubility. Their structures were characterized by 1H NMR spectroscopy, electrospray ionization mass spectrometry, and elemental analysis and in the cases of 1·8BF4– ([(phen)8Pd8L14](BF4)8), and 3·4BF4– ([(phen)4Pd4L22](BF4)4) by single-crystal X-ray diffraction analysis. Complexes 3–8 are square-type hybrid metallomacrocycles, while complexes 1 and 2 exhibit folding cyclic structures. Interestingly, in single-crystal structures of 1·8BF4– and 3·4BF4–, BF4– anions are trapped in the dipalladium clips through anion−π interaction. The luminescence properties and interaction toward anions of these metallomacrocycles were discussed.

The self-assembly of (TMEDA)Pd(NO3)2 or (TMEDA)Pt(NO3)2 (where TMEDA = N1,N1,N2,N2-tetramethylethane-1,2-diamine) and anthracene- or ferrocene-based diimidazole ligands (L1–3) in aqueous solution affords a series of positively charged [M2L2]4+ dimetallomacrocycles. Their structures were characterized by 1H NMR and electrospray ionization mass spectrometry and in the cases of {[(TMEDA)Pd]2L12}(NO3)4 (1), {[(TMEDA)Pd]2L12}(PF6)4 (1a), and {[(TMEDA)Pd]2L32}(NO3)4 (4) by single-crystal X-ray diffraction analysis. Interestingly, the NMR spectra of 1 and 1a revealed that the difference of their structures, as confirmed by X-ray diffraction analysis, was that a NO3– of 1 was encapsulated inside the cavity of the basket-shaped metallomacrocycle by C–H···O hydrogen bonds, while PF6– of 1a was bound outside by C–H···F hydrogen bonds. The fluorescence titration experiment exhibited the formation of 1:1 host–guest complexation for anthracene-based positively charged [M2L2]4+-type metallomacrocycles with NO3–. The interactions between metallomacrocycles and various anions were investigated via fluorescence titration and cyclic voltammetry studies, respectively.

By employing diimine ligands coordinated dimetallic clips ([(bpy)2Pd2(NO3)2](NO3)2 or [(phen)2Pd2(NO3)2](NO3)2, where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) as the corner and anthracene-, naphthalene-, and benzene-based dipyrazolate dianions as the linker, a series of positively charged metallomacrocycles ([M4L2]4+ or [M8L4]8+) have been synthesized through a directed self-assembly method in aqueous solution. Every macrocycle has a cavity to bind solvent molecules or anions. The structures were characterized by elemental analysis, 1H and 13C NMR, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis for compound 1·4PF6¯ (1 = {[(bpy)Pd]4L12}4+), 3·4PF6¯·8CH3CN·H2O (3 = {[(bpy)Pd]4L22}4+), and 7·4PF6¯·6H2O (7 = {[(bpy)Pd]4L52}4+). The 1:1 host−guest complexation for anthracene-based dipyrazolate-bridged macrocycles with aromatic guests was investigated via UV−vis and fluorescent titration.

By employing different diimine complexes and a naphthanoimidazolate (L1) or benzoimidazolate (L2) anion ligand as linker, a series of trimetallo-macrocycles have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the ligands in aqueous solution. Some compounds, namely, [M3L3](NO3)3 (M = (18-crown-6-phen)Pt, 1 or 7; (15-crown-5-phen)Pt, 2; (benzo-24-crown-8-phen)Pt, 8; (benzo-24-crown-8-phen)Pd, 9; (15-crown-5-phen)Pd, 4 or 11; (18-crown-6-phen)Pd, 3 or 10; (dmbpy)Pd, 6 or 14; (bpy)Pd, 5 or 13; (bpy)Pt, 12; (N4-Phen)Pd, 15) were synthesized. In all of these compounds, the L1or L2 anion ligands are in a syn, syn, syn orientation which result in a bowl-like cavity that can serve as a host to bind the methyl of a solvent CH3CN within the naphthanoimidazolate or benzoimidazolate-built cavity through C–H⋯π hydrogen bonds in the crystal state. The structures are characterized by elemental analysis, 1H NMR, ESI-MS, and in the cases of 4a, 11, 13, and 14a by single-crystal X-ray diffraction analysis.

By employing di-palladium complexes [(N^N)2Pd2(NO3−)2](NO3−)2 (where N^N = 2,2′-bipyridine, bpy; 4,4′-dimethylbipyridine, dmbpy; 1,10-phenanthroline, phen) as corners and tripyrazole functional ligands (H3L1–H3L5) as linkers, a series of highly-positively-charged tripyrazolate-bridged metallo-cages with different conformations and cavities such as [Pd6L2]6+ (1 or 5, where L = L1 or L5), [Pd10L24]10+ (2a, 2b and 4b, where L = L2 or L4) and [Pd12L4]12+ (3 or 4a, where L = L3 or L4) have been synthesized through a di-metal coordination directed self-assembly with spontaneous deprotonation of the tripyrazole ligands in aqueous solution. These complexes have been fully characterized by 1H and 13C NMR, cold-spray ionization or electron spray ionization mass spectrometry (CSI-MS, ESI-MS) and elemental analysis. Complexes 1, 2a, 2b, 3 and 4 have also been determined by single-crystal X-ray diffraction structural analysis. In the case of complex 3, six PF6− anions were encapsulated within the cavity composed of adjacent di-Pd corners.

By employing different diimine complexes and a naphthanoimidazolate (L1) or benzoimidazolate (L2) anion ligand as linker, a series of trimetallo-macrocycles have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the ligands in aqueous solution. Some compounds, namely, [M3L3](NO3)3 (M = (18-crown-6-phen)Pt, 1 or 7; (15-crown-5-phen)Pt, 2; (benzo-24-crown-8-phen)Pt, 8; (benzo-24-crown-8-phen)Pd, 9; (15-crown-5-phen)Pd, 4 or 11; (18-crown-6-phen)Pd, 3 or 10; (dmbpy)Pd, 6 or 14; (bpy)Pd, 5 or 13; (bpy)Pt, 12; (N4-Phen)Pd, 15) were synthesized. In all of these compounds, the L1or L2 anion ligands are in a syn, syn, syn orientation which result in a bowl-like cavity that can serve as a host to bind the methyl of a solvent CH3CN within the naphthanoimidazolate or benzoimidazolate-built cavity through C–H⋯π hydrogen bonds in the crystal state. The structures are characterized by elemental analysis, 1H NMR, ESI-MS, and in the cases of 4a, 11, 13, and 14a by single-crystal X-ray diffraction analysis.

By employing dipalladium corners [(bpy)2Pd2(NO3)2](NO3)2 or [(phen)2Pd2(NO3)2](NO3)2 (where bpy = 2,2′-bipyridine and phen = 1,10-phenanthroline) to bridge ferrocene-based dipyrazole ligand (L11) and m-phenylene-based dipyrazole ligands (L2–32–3) in aqueous solution, a series of positively-charged [M4L2]4+ metallomacrocycles were obtained. Their structures were characterized by 1H NMR, electrospray ionization mass spectrometry (ESI-MS), elemental analysis, and single crystal X-ray diffraction analysis for 1·4NO3 ({[(bpy)Pd]4L112}(NO3)4) and 4·4NO3 ({[(phen)Pd]4L222}(NO3)4). In their single crystal structures, NO3− anions are located at the dipalladium corners by C–H⋯O hydrogen bonds. Importantly, the anion-sensing properties of ferrocene functionalized [Pd4Fe2] hetero-metallomacrocycle 1 were investigated in acetonitrile by SWV, CV and NMR analysis, showing promise for Br− sensing.

The dimetallic [M2(bpy)2(NO3)2](NO3)2 moieties (M = Pd(II) or Pt(II)) react preferentially at the pyrazolyl end of the pyridyl-pyrazole ligand, giving rise to dimetallic corners. Subsequently, the dimetallic corner building blocks featuring two pyridine donors are coordinated by monometallic [M(bpy)(NO3)2] moieties (M = Pd(II) or Pt(II)) to form homo- or hetero-metallomacrocycles.