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The coordination of alkaline earth metal cations (AE2+ = Mg2+, Ca2+, Sr2+, Ba2+) with inverted hexamethylcucurbit[3,3]uril {iMe6Q[3,3]} has been investigated in the presence of polychlorido cadmium anions as structure directing agent. Single-crystal X-ray diffraction analysis has revealed that the interactions of iMe6Q[3,3] with AE2+ cations result in the formation of linear iMe6Q[3,3]-based coordination polymers from iMe6Q[3,3]-AECl2-CdCl2-HCl systems. Generally, Cd2+ cations can form [CdCl4]2− anions that serve as structure directing agent in the formation of iMe6Q[3,3]/AE2+-based coordination polymers. Moreover, iMe6Q[3,3]-AECl2-CdCl2-HCl systems exhibit high affinity for the heavier AE2+, such as Sr2+, and Ba2+.

We report the preparation and single crystal X-ray diffraction analysis of three supramolecular self-assemblies based on perhydroxycucurbit[5]uril {(HO)10Q[5]}, Keggin-type heteropolyacids (HPAs), and potassium or barium cations. Crystallographic data revealed that all 3D self-assemblies are constructed by a stack of 2D layered structures composed of (HO)10Q[5]/K+ or (HO)10Q[5]/Ba2+ complexes cations and HPAs anions. Although there are differences in 2D layered structures, all the driving force comes from the outer surface interactions of (HO)10Q[5] including: (1) typical hydrogen bonding by hydroxyl groups and atypical hydrogen bonding by methylene on the outer surface of (HO)10Q[5]; (2) dipole interaction between the positively charged methylene or carbonyl carbon atoms of (HO)10Q[5] and the negatively charged oxygen atoms of the HPAs; (3) The electrostatic interaction between the (HO)10Q[5]/metal cations and the HPAs anions plays a main role in self-assembling.

The esterification reaction used to prepare butyl paraben (BP) and propyl gallate (PG) catalyzed using a cucurbit[6]uril-supported Keggin-type silicotungstic acid (Q[6]-STA) catalyst has been investigated. The Q[6]-STA catalyst has been characterized using FTIR spectroscopy, XRD, SEM, EDS, thermal analysis, and surface area studies. Q[6]-STA was easy to prepare in high yield and exhibited some advantageous properties, such as high catalytic activity and its convenient recovery. Moreover, a reusability study showed that the Q[6]-STA catalyst was stable and active.

We investigated the interactions in an inverted cucurbit[6]uril ( i Q[6]) with a series of 1, ω -alkyldimins and their supramolecular assemblies in the presence of the tetrachlorozincate anion ([ZnCl 4 ] 2− ) structure directing agent. i Q[6] forms an outer surface interaction with [ZnCl 4 ] 2− to form different i Q[6]/[ZnCl 4 ] 2− -based supramolecular assemblies with different length 1,ω-alkyldimins. Interestingly, most 1,ω-alkyldimins were not visible in crystals structures in the presence of concentrated HCl. The porous i Q[6]/[ZnCl 4 ] 2− -based supramolecular assemblies could be used as materials for adsorbing volatile compounds.

The interactions of alkali metal (A+ = Na+, K+, Rb+, Cs+) and alkaline earth metal cations (AE2+ = Mg2+, Ca2+, Sr2+, Ba2+) with mono-hydroxylated octamethylcucurbit[6]uril {(OH)OMeQ[6]} have been investigated in the presence of polychloride cadmium anions as structure-directing agents. Single-crystal X-ray diffraction analysis has revealed that the interactions of (OH)OMeQ[6] with A+ or AE2+ cations results in the formation of (OH)OMeQ[6]-based coordination complexes from (OH)OMeQ[6]–ACl or AECl2–CdCl2–HCl systems, in which Cd2+ cations form [Cd2Cl8]4− or [CdCl4]2− anions that serve as structure-directing agents in the formation of (OH)OMeQ[6]/A+ or AE2+-based supramolecular assemblies.

The interaction of a series of lanthanide cations (Ln3+) with a di-hydroxylated symmetrical octamethyl-substituted cucurbituril {(OH)2OMeQ[6]} has been investigated. Single-crystal X-ray diffraction analysis has revealed that the interaction results in the formation of adducts of (OH)2OMeQ[6] with aqua complexes of lanthanide cations ([Ln(H2O)8]3+), Ln = Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in (OH)2OMeQ[6]–Ln(NO3)3–H2O systems. However, no solid crystals were obtained from systems containing La, Ce, Pr, Nd and Sm. X-ray diffraction analysis has revealed that although the solid adducts fall into two isomorphous groups, there are no significant differences in the interactions between (OH)2OMeQ[6] and [Ln(H2O)8]3+ complexes and in the corresponding supramolecular assemblies. Thermodynamic parameters for the interaction between (OH)2OMeQ[6] and [Ln(H2O)8]3+ complexes based on isothermal titration calorimetry experiments show two periods corresponding to the above two systems, with the lighter lanthanide cations preferring to remain in solution and the heavier lanthanide cations forming crystalline solids. Energy dispersive spectroscopy (EDS) has shown that the interaction of OMeQ[6] with lanthanide cations could provide a means of isolating heavier lanthanide cations from their lighter counterparts.

Interactions of alkali cations (A+ = Na+, K+, Rb+, Cs+) with a symmetrical octamethyl-substituted cucurbituril (OMeQ[6]) have been investigated in the presence of different structure-directing agents. Single-crystal X-ray diffraction analysis has revealed that the interaction results in the formation of coordination complexes of OMeQ[6] with K+ and Cs+ cations in OMeQ[6]–ACl–HCl systems, whereas no complexes were obtained from systems containing Na+ and Rb+ in the presence of polychloride cadmium anions such as [Cd2Cl8]4−, [CdCl4]2−, or [Cd2Cl7]3− as structure-directing agents; in the presence of p-hydroxybenzoic acid (Hyb) as a structure-directing agent, the interaction results in the formation of coordination complexes of OMeQ[6] with Na+ and Cs+ cations in OMeQ[6]–ACl–H2O systems. More importantly, in the presence of these different structure-directing agents, OMeQ[6] or OMeQ[6]/A+ complexes can form different supramolecular assemblies based on the outer surface interaction of Q[n].

In this study, fully substituted cyclopentano cucurbit[5]uril (CyP 5 Q[5]) were coordinated with an alkaline earth cations (AE 2+ ) in the presence of tetrachlorozincate anions ([ZnCl 4 ] 2− ). Single-crystal X-ray diffraction analysis revealed that the CyP 5 Q[5]–Mg 2+ –[ZnCl 4 ] 2− –HCl interaction system yielded an Mg 2+ /Cl − @CyP 5 Q[5]-type molecular bowl, with a chloride anion in the cavity of the CyP 5 Q[5] moiety. The CyP 5 Q[5]–Ca 2+ and Sr 2+ –[ZnCl 4 ] 2− –HCl interaction systems yielded isolated AE 2+ /CyP 5 Q[5]/AE 2+ -type molecular capsules, again with a chloride anion in the CyP 5 Q[5] cavity. A honeycomb effect was evident in all three systems, in which the of the [ZnCl 4 ] 2− anions surround the CyP 5 Q[5] molecules through outer surface interactions between Q[n] and electrostatic interactions with AE 2+ cations, resulting in the formation of porous supramolecular assemblies. Direct coordination between Ba 2+ and CyP 5 Q[5] yielded zigzag coordination polymers. The CyP 5 Q[5]/AE 2+ -based supramolecular assemblies (AE = Mg, Ca, Sr, Ba) presented different porous conformations and displayed differential absorption of volatile compounds.

Coordination of an inverted cucurbit[7]uril (iQ[7]) with a series of alkali cations (A+), revealed that iQ[7] can interact with potassium to form iQ[7]-K+-based porous coordination polymer in the presence of [ZnCl4]2 − anions as a structure directing agent. Unexpectedly, isothermal titration calorimetry revealed no obvious interaction of iQ[7] with any A+ cation. Moreover, the iQ[7]-K+-based porous coordination polymer showed selective sorption of polar volatile organics, which may have potential applications for molecular sieves, sensors, and absorption and separation processes.

We have investigated the interactions of the lanthanum cation (La3 +) with cucurbit [6]uril (Q [6]) and its alkyl-substituted derivatives (SQ [6]s), including symmetrical tetramethylcucurbit [6]uril (TMeQ [6]), symmetrical dicyclohexanocucurbit [6]uril (1,4-DiCyHQ [6]), and percyclohexanocucurbit [6]uril (CyH6Q [6]), as well as the supramolecular assemblies formed with the aid of inorganic anions (NO3− and Cl−) as structure-directing agents. Single-crystal X-ray diffraction analysis has revealed that the interaction results in the formation of three kinds of coordination complexes. The main driving forces may be the ion-dipole interaction of inorganic anions and the electropositive outer surface of Q[n].

Coordination of lanthanide cations (Ln3+) and a symmetrical dicyclohexanocucurbit[6]uril (1,4-DiCyHQ[6]) in the presence of tetrachlorozincate was investigated. X-ray single crystal diffraction analysis revealed that with [ZnCl4]2− anions as a structure directing agent, the interaction of lighter lanthanide cations and 1,4-DiCyHQ[6] results in the formation of fast precipitation, whereas the interaction of heavier lanthanide cations and 1,4-DiCyHQ[6] results in solid crystals. This provides a potential strategy for separating lighter and heavier lanthanide cations.

Two Q[n]-based porous compounds, Q[5]·[PtCl6]2 −·2H3O·12H2O and 2Q[8]·[PtCl6]2 −·2H3O·74H2O in cooperating the hexachloroplatinate(IV) anion ([PtCl6]2 −) as an inorganic structure directing agent are demonstrated. The driving forces for the formation of such novel Q[n]-based porous compounds are considered to be the outer surface interactions of Q[n]s, including dipole interactions between Q[n]s and ion-dipole interactions between [PtCl6]2 − anions and Q[n]s. Moreover, the Q[5]-based porous compound displays absorption distinctness for tetrachloromethane, whereas the Q[8]-based porous compound displays absorption distinctness for methanol.

Coordination of fully substituted cyclopentano cucurbit[5]uril (CyP5Q[5]) with an alkali cation (A+) in the presence of tetrachloridezicate anions was investigated. Single-crystal X-ray diffraction analysis revealed that the CyP5Q[5]–Na+ and K+–[ZnCl4]2−–HCl interaction systems yielded an A+/Cl−@CyP5Q[5]/A+-type molecular capsule, and that a chloride anion was included in the cavity of the CyP5Q[5] molecule. [ZnCl4]2− anions were not involved in direct coordination with the A+/Cl−@CyP5Q[5]/A+ capsule. The CyP5Q[5]–Rb+ and Cs+–[ZnCl4]2−–HCl interaction systems yielded an A+/CyP5Q[5]/A+-type molecular capsule shell, and no chloride anions were included in the cavity of the CyP5Q[5] molecule. [ZnCl4]2− anions directly interacted with coordinated Rb+ or Cs+ cations through electrostatic interaction, and [ZnCl4]2− anions in particular played the role of linkers, resulting in the formation of a linear supramolecular assembly ⋯[ZnCl4]2−–A+/Cl−@CyP5Q[5]/A+–[ZnCl4]2−–A+/Cl−@CyP5Q[5]/A+⋯. Close inspection revealed that the obtained CyP5Q[5]/A+-based supramolecular assemblies (A = Na, K, Rb, Cs) presented different porous conformation and could show different absorption properties.

The interaction of the alkaline-earth metal ions Mg2+, Ca2+, Sr2+ and Ba2+ with the symmetrical octamethyl-substituted cucurbituril, OMeQ[6], in the presence of [CdCl4]2−/[Cd2Cl8]4− anions as structure-directing agent(s) in 3 M HCl has been investigated. Ca2+ and Sr2+ yielded closely related metallosupramolecular assemblies whose X-ray structures show that in the former, [Cd2Cl8]4− anions are arranged to form parallelogram-like frameworks that surround linear OMeQ[6]/Ca2+ polymeric units. The structure of the OMeQ[6]/Sr2+ assembly is similar except that the [Cd2Cl8]4− anions in the OMeQ[6]/Ca2+ assembly are replaced by [Cd2(H2O)2Cl8]4− anions. In contrast to the above structures, interaction of the larger Ba2+ ion with OMeQ[6] gives rise to a different assembly type displaying a porous linear polymeric arrangement incorporating two different Ba2+ coordination modes; [Cd2Cl4]4− anions are associated with the Ba2+ bridges linking adjacent OMeQ[6] units in the polymeric chain. In contrast to Ca2+ and Sr2+, the smaller Mg2+ ion under similar synthetic conditions failed to yield a solid product. Isothermal titration calorimetry (ITC) studies revealed that OMeQ[6] interacts with Ca2+, Sr2+ and Ba2+, but not Mg2+, in neutral aqueous solution. The respective X-ray structures reveal the presence of both channels and other voids in the three assemblies. Following application of a vacuum until constant weight was obtained, samples of the Sr2+ and Ba2+ assemblies were subjected to the saturated vapour of each of the following volatile ligands: acetonitrile, methanol, ethanol, acetone, diethylether, dichloromethane, cyclohexane and n-hexane. The respective absorption profiles show maximum absorption for methanol, with reduced uptake for the remaining larger and/or less polar guest molecules.

The interaction and supramolecular assemblies of two alkaline earth metal ions, Ca2+ and Ba2+, with methyl-substituted cucurbit[6]uril derived from 3α-methyl-glycoluril (HMeQ[6]) in aqueous HCl solution have been investigated. X-ray diffraction analysis revealed that coordination of HMeQ[6] with these metal ions resulted in the formation of one-dimensional coordination polymers in the presence of polychloride transition metal anions, such as [CdCl4]2−, as structure-directing agents. The supramolecular frameworks exhibit excellent thermal stability as well as permanent porosity. The activated desolvated materials show high Et2O and CH3OH adsorption capacity and selectivity compared with other porous organic materials assembled solely through hydrogen bonding under ambient conditions.

The interaction of a series of lanthanide cations (Ln3+) with inverted cucurbit[7]uril (iQ[7]) in the presence of [ZnCl4]2− anions as a structure-directing agent have been investigated.

Coordination and supramolecular assemblies of a fully substituted cyclopentanocucurbit[6]uril (CyP6Q[6]) with a series of lanthanide cations (Ln3+) have been investigated in the presence of tetrachlorozincate anion ([ZnCl4]2–). X-ray single-crystal diffraction analysis has revealed that the interaction of CyP6Q[6] and a series of Ln3+cations unexpectedly results in the formation of at least seven different CyP6Q[6]-based coordination complex adduct and supramolecular assemblies groups, including with (1) La3+, Ce3+cations; (2) Pr3+, Nd3+cations; (3) Eu3+, Gd3+, Tb3+, Dy3+ with P1 or P1 space group, in which CyP6Q[6] molecules coordinate alternatively with Ln3+cations and form linear coordination polymers; (4) CyP6Q[6] molecules interact alternatively with [Ho(H2O)8]3+ aqueous complexes and form linear supramolecular chains; CyP6Q[6] molecules can assemble two different Ln3+ free porous supramolecular assemblies from CyP6Q[6]–Ln(NO3)3–ZnCl2–HCl systems, Ln = Tm, Yb, and Lu; however, no solid crystals were...

The interactions between a series of lanthanide cations (Ln3+) and a methyl-substituted cucurbit[6]uril derived from 3α-methyl-glycoluril (SHMeQ[6]) in the presence of [CdCl4]2 − as a structure-directing agent in aqueous HCl solutions (6.0 mol·L − 1) have been investigated. The formation of ionic radius-dependent complexes, the crystal structures of six of which have been obtained, shows the recognition ability of SHMeQ[6] towards lanthanide cations. For example, SHMeQ[6] forms molecular capsule-like complexes with the two lightest lanthanide cations, La3+ and Ce3+; molecular pairs with Nd3+, Sm3+, Eu3+ and Gd3+, and no solid crystals are formed with the heavier lanthanides.

Coordination of supramolecular assemblies was investigated by reacting a series of lanthanide cations (Ln3+) with an inverted cucurbituril (iQ[6]) in the presence of tetrachloride zincate anion [ZnCl4]2−, as an structure directing agent in aqueous HCl (3.0 mol/L). Single crystal X-ray diffraction analysis revealed that the coordination of iQ[6] with Ln3+ gave rise to different interaction products and isomorphous groups with increasing atomic number. The interaction of iQ[6] with La3+ and Ce3+ immediately yielded precipitations and single crystal solids containing Pr3+ and Nd3+. No solids resulted from coordination of iQ[6] with Sm3+ and Eu3+, whereas single crystals solids were obtained from coordination of iQ[6] with heavy Ln3+, such as Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+. Such coordination characteristics may offer a strategy for isolating a series of Ln3+ cations in patches.

The coordination and supramolecular assemblies of lanthanide cations and perhydroxycucurbit[5]uril {(HO)10Q[5]} in the presence of [SiW12O40]4– anions and transition metal salts show significant differences as the lanthanide atomic number increases. The molecular capsule (HO)10Q[5] coordinates with the light lanthanide cations Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, and Tb3+ but does not coordinate with heavier Ln3+ cations. However, (HO)10Q[5]/Na+-based molecular capsules form in the presence of the heavier lanthanide cations Ho3+, Er3+, Tm3+, Yb3+, and Lu3+ under the same synthetic conditions. These differences could be key in establishing a strategy for the isolation of light lanthanides from their heavier counterparts.

The supramolecular assemblies formed from lanthanide cations (Ln3+) and a new alkyl-substituted cucurbituril, the ortho-tetramethyl substituted cucurbituril (o-TMeQ[6]), in neutral solution were investigated. X-ray single crystal diffraction analysis revealed that interactions of the aqua complexes of lanthanide cations with o-TMeQ[6] gives rise to an isomorphous group of compounds when heavy lanthanide cations such as Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+ are employed. Interestingly, no solid crystals were obtained from o-TMeQ[6]–Ln3+ systems of La, Ce, Pr, Nd, Sm, Eu or Gd, suggesting that these interactions could be used for the isolation of heavier lanthanide cations from their lighter counterparts.

The interactions between a series of lanthanide cations (Ln3+ ) and methyl-substituted cucurbiturils (SPMeQ[5] and SHMeQ[6]) derived from a 3α-methyl glycoluril have been investigated. Single-crystal X-ray diffraction analysis revealed that both SPMeQ[5] and SHMeQ[6] selectively interact with certain lanthanide ions. SPMeQ[5] forms coordination capsules in the presence of [CdCl4 ]2- . The Ln3+ cations that interact are the four light lanthanides, La3+ , Ce3+ , Pr3+ , and Nd3+ , whereas the remaining lanthanide cations remain in solution. SHMeQ[6] formed adducts of SHMeQ[6] with aqua complexes of lanthanide cations ([Ln(H2 O)8 ]3+ ); for SHMeQ[6]-Ln(NO3 )3 -CdCl2 -HCl systems (Ln=Gd-Lu), no solid crystals were obtained from systems that contained La, Ce, Pr, Nd, Sm, or Eu. Whereas solid crystals of adducts of SHMeQ[6] with aqua complexes of lanthanide cations (Ln=Sm-Lu) formed SHMeQ[6]-Ln(NO3 )3 systems in neutral solution, no solid crystals were obtained from systems that contained La, Ce, Pr, or Nd. These results suggest that SPMeQ[5]- and SHMeQ[6]-Ln(NO3 )3 systems could be useful for the selective isolation of these lighter or heavier lanthanide cations from mixtures. Energy-dispersive spectrometry indicated that the lighter or heavier lanthanide cations could be isolated from their heavier or lighter counterparts through interaction with SPMeQ[5] and SHMeQ[6].

Coordination assemblies have been investigated by reactions between alkali metal salts and a meta-hexanomethyl-substituted cucurbit[6]uril (m-HMeQ[6]) in aqueous solutions. X-ray diffraction analysis revealed that each m-HMeQ[6] coordinates with three alkali metal ions, K+, Rb+ or Cs+ and forms a 1:2, m-HMeQ[6]:Malkali+ complex. This complex forms a one-dimensional supramolecular chain through hydrogen bonding. The m-HMeQ[6]/Malkali+ complex-based chains often form honeycomb-like frameworks in which each channel is filled with counter anions and water molecules. The driving forces resulting in the formation of such supramolecular assemblies could be attributed to the outer-surface interaction of Q[n]s.

The interaction of alkaline-earth cations (AE2+) with hexanohydroxyhexanomethylcucurbit[6]uril (HHQ[6]) in the presence of CdCl2 in aqueous HCl solution was investigated. Single crystal X-ray diffraction analysis revealed that the interaction results in the formation of one-dimensional coordination polymers of HHQ[6] with AE2+ (Ca, Sr or Ba). In addition, compounds containing Ca and Sr are isomorphous. Moreover, the compound obtained from the HHQ[6]–MgCl2–CdCl2–HCl system contained only a metal-free HHQ[6]-based supramolecular assembly. ITC experiments showed that the interaction between HHQ[6] and Mg2+ could not be effectively measured, and that the interaction of Ca2+ or Sr2+ with HHQ[6] are driven by ΔH and ΔS, whereas the interaction between Ba2+ and HHQ[6] is driven by ΔH.

Coordination in supramolecular assemblies in aqueous HCl solutions was investigated by reacting alkaline-earth cations (AE2+) and inverted cucurbit[6]uril (iQ[6]) in the presence of the structure-directing agent, tetrachloride zincate ion. Single-crystal X-ray diffraction analysis revealed that the iQ[6]–Mg2+–[ZnCl4]2––HCl interaction system yielded a supramolecular assembly of iQ[6] and [ZnCl4]2– without forming coordination complexes of Mg2+ or Zn2+ with iQ[6]. In contrast, interaction of Ca2+ or Sr2+ with iQ[6] in the presence of [ZnCl4]2– gave rise to linear coordination polymers, which formed a honeycomb-like framework in which the linear polymers occupy cells of the framework. The iQ[6]–Ba2+–[ZnCl4]2––HCl interaction system immediately produced precipitates, thus preventing isolation of single crystals under similar synthetic conditions.

o-Tetramethyl-substituted cucurbituril (o-TMeQ[6]), a polydentate ligand, has been synthesized and isolated in a controlled manner by using a dimer of dimethyl-substituted glycoluril and a dimer of unsubstituted glycoluril. Coordination assemblies have been investigated by reactions between alkaline earth cations and o-TMeQ[6] in the presence of [CdCl4]2–, a structure inducer, in HCl aqueous solution. X-ray diffraction analysis revealed that o-TMeQ[6] coordinates with Ca2+ or Sr2+ and forms centrosymmetric tetranuclear assemblies in the presence of [CdCl4]2–. [CdCl4]2– typically produces the “honeycomb effect” by forming honeycomb-like frameworks, which assist metal ions in coordinating to o-TMeQ[6]. The driving forces of this effect are the “outer-surface interactions” of cucurbit[n]urils.

In the present work, we describe four previously unreported cucurbituril-based coordination supramolecular self-assemblies, formed in the presence of alkali metal and cadmium ions. Unexpectedly, in the presence of potassium or rubidium and cadmium cations, cucurbituril prefers to coordinate with cadmium to form three dimensional frameworks. The alkali metal ions seem to play a role of structure inducer in HCl medium and are not present in the final structures. In neutral aqueous solution, cadmium cations also show stronger coordination to cucurbituril and form one-dimensional supramolecular chains through static electronic interactions. When the alkali metal ion is sodium in HCl solution, sodium ions show stronger coordination to cucurbituril and form one-dimensional coordination polymers. [CdCl4]2– anions link the linear polymers through static electronic interactions between coordinated chloride anions and sodium cations, which results in the formation of two-dimensional networks.

In the present work, we demonstrate the formation of a typical cucurbit[6]uril (Q[6])-based porous material in the presence of the hexachloroplatinate(IV) anion [PtCl6]2– as an inorganic structure inducer. The driving forces for the structure directing effect of the [PtCl6]2– anion could be attributed to ion–dipole and hydrogen-bonding interactions between the anion and the ≡CH or =CH2 groups on the back of the Q[6] molecule.

A Cu(II) Schiff base coordination polymer, {[Cu 3 L( μ 2 - NO 3 ) 2 ·(H 2 O) 2 ].3H 2 O} n , is readily prepared by complexation of the tetrapodal Schiff base, H 4 L (H 4 L = 1,1,1,1-tetrakis[(salicylaldimino)methyl]methane), with cupric nitrate trihydrate. It has been demonstrated that the coordination polymer consists of linear trinuclear Cu(II) entities, and displays a cooperative coordination mode for nitrate anions, coordinated water molecules, and Schiff base ligands to Cu(II) ions. In addition, variable-temperature magnetic susceptibility measurements reveal a strong antiferromagnetic coupling interaction between adjacent copper(II) ions with large J value of − 289.66 cm − 1 .

Five silver coordination polymers, namely, {[Ag(3,3′-daps)2]·BF4}n (1), {[Ag(3,3′-daps)2]·NO3}n (2), [Ag(3,3′-daps)(CF3SO3)]n (3), {[Ag(4,4′-daps)]·CF3SO3}n (4), and {[Ag(4,4′-daps)]·ClO4}n (5) (3,3′-daps=di(3′-aminodiphenyl)sulfone, and 4,4′-daps=di(4′-aminodiphenyl)sulfone) have been synthesized and structural characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction analyses. Complex 1 displays a 1D ladder-like chain with four-connected Ag ions and bridged 3,3′-daps. Complex 2 shows other 1D ladder chain modified by tentacles. Complex 3 is a 2D layer structure with both Ag ions and 3,3′-daps are 3-connected nodes. Complex 4 is another 1D ladder chain with three-connected Ag ions and 4,4′-daps. Complex 5 shows a 2D 44-sql net with Ag ions and 4,4′-daps as 4-connected nodes. Moreover, their solid state luminescence and thermal stabilities also have been investigated.

Coordination in supramolecular assemblies was investigated by reacting a series of lanthanide cations (Ln3+) and a new alkyl-substituted cucurbituril, the ortho-tetramethyl-substituted cucurbituril (o-TMeQ[6]), in the presence of cadmium nitrate as an inorganic structure inducer in neutral solution. X-ray diffraction analysis revealed that the coordination of lanthanide cations gives rise to two isomorphous groups bound to three and eight isomorphous compounds, respectively. One group is typical of the coordination of o-TMeQ[6] with light lanthanide cations such as Nd3+, Sm3+ and Eu3+, while the other group is characteristic of the coordination of o-TMeQ[6] with heavy lanthanide cations such as Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+. Most interestingly, no solid crystals were obtained for any compounds containing La, Ce, or Pr, suggesting that these compounds may be suitable for the separation of heavier lanthanide cations from their lighter counterparts.

In the present work, we describe three cucurbit[7]uril-based coordination supermolecular self-assemblies in the presence of [M(trans)Cl4](2-). It can affect the construction of Q[7]/metal ions-based coordination polymers, at the same time it can result in the formation of Q[7]-based supramolecular assemblies when introducing the [M(trans)Cl4](2-) into the Q[7]/metal ions system.

We prepared two new types of (HO)10Q[5]-based supramolecular assemblies by using the [PMo12O40]3– anion as a structure inducer. Single-crystal X-ray diffraction analysis revealed that these two types of (HO)10Q[5]/[PMo12O40]3– hydrides were constructed from (HO)10Q[5]/[PMo12O40]3–-based 2D networks in which [PMo12O40]3– plays a key rule in attracting (HO)10Q[5] molecules through (1) classical hydrogen bonding of the functionalized hydroxy groups on the back of the (HO)10Q[5] molecules, (2) unusual hydrogen bonding of the methylene groups on the back of the (HO)10Q[5] molecules, and (3) interaction between electron-deficient carbon sites of the carbonyl groups of the (HO)10Q[5] molecules with electron-rich oxygen sites of the Mo–O groups from the [PMo12O40]3– anions. An additional electrostatic interaction could exist in K+-coordinated (HO)10Q[5] complexes.

The coordination of pentacyclohexanocucurbit[5]uril (PCyHQ[5]) to alkali metal cations and the formation of supramolecular assemblies in the absence and presence of [CdCl4]2– or [ZnCl4]2– anions as inorganic structure inducers have been investigated by single-crystal X-ray diffraction analysis. Studies of the crystal structures have revealed that the [CdCl4]2– or [ZnCl4]2– anions do not form honeycomb structures owing to the presence of alkyl substituents on the surface of the outer walls of PCyHQ[5], which can seriously perturb the interaction of the anions with the outer walls. Moreover, in the presence of [ZnCl4]2– anions, the formation of a new Rb-PCyHQ[5]-based 2D six-membered “bracelet” network suggests that larger ions such as Ba2+ and even Ra2+ could form this new type of supramolecular assembly.

In this study, we describe the interaction of copper cations with alkyl-substituted cucurbiturils (SQ[6])s in the absence and presence of a third species, and show how the corresponding supramolecular assemblies depend on the addition of the third species. In the absence of the third species, the SQ[6]s resulted in similar coordination with copper cations and the formation of supramolecular assemblies as the unsubstituted cucurbituril (Q[6]). The Cu2+ cation was coordinated to a cyclopentanocucurbit[6]uril (CyP6Q[6]) with the counter anion NO3− and formed a zigzag coordination chain. In contrast, the Cu2+ cation coordinated to a symmetrical tetramethylcucurbit[6]uril (TMeQ[6]) with the counter anion Cl− and formed a tubular coordination polymer. However, when SO42− was introduced into the Cu2+–TMeQ[6] system, only isolated complexes consisting of linear coordination polymers of Cu2+ to TMeQ[6] were formed. By comparison, when the organic molecule p-phenylenediamine was introduced into the CuCl2–TMeQ[6]–HCl system, no Cu2+–TMeQ[6] complexes were formed at all but p-phenylenediamine@TMeQ[6] host–guest inclusion complexes were observed.

In the present study, the lanthanide(III) contraction effect induced coordination architectures of HCyHQ[6] have been studied. The results, including fifteen crystal structures, indicate that although lanthanide metal ions have similar chemical properties mostly, their slightly different ionic radii play a key role in the formation of different supramolecular self-assembly types of HCyHQ[6]. As a result, the ionic radius-dependent complexes of HCyHQ[6] can be structurally classified into four groups: HCyHQ[6]-pair, HCyHQ[6]-molecular bowl, Ln–HCyHQ[6] one dimensional coordination polymer, and HCyHQ[6]-molecular capsule.

In the present study, we report three crystal structures of heterometallic Q[5]-based complexes. They are complexes of heterometallic cadmium and potassium ions/Q[5] capsules with a stoichiometry of {(CdCl)[K(H 2 O)][Cl@Q[5]]} + [CdCl 3 (H 2 O) 2 ] − 7H 2 O ( 1 ), heterometallic praseodymium and calcium/Q[5] pairs with a stoichiometry of 2{[Ca(H 2 O)(OH)]- μ -[Pr(H 2 O) 3 [Cl@Q[5]]]} 3+ 6Cl − 32H 2 O ( 2 ) and discrete heterometallic neodymium and potassium ions/Q[5] capsules with a stoichiometry of {[Nd(H 2 O) 3 ][(NO 3 )@Q[5]][K(H 2 O)][Nd(H 2 O) 3 (NO 3 ) 4 ]} 2+ 2(NO 3 ) − 8H 2 O ( 3 ).

In the present study, the coordination and supramolecular self-assemblies of a series of alkali and alkaline earth metal ions to cucurbit[5]uril in the presence of nitrophenol are introduced. The experimental results have proven that the presence of nitrophenol and the ionic radiuses of the metal ions influence greatly the coordination and supramolecular self-assemblies of these metal ions to Q[5] molecule. Compared to in the absence of p-nitrophenol, the presence of p-nitrophenol seems to frustrate the formation of the K-Q[5] coordination polymer, while the presence of p-nitrophenol induces the formation of Rb- and Cs-Q[5] coordination polymers. Basically, one-dimensional supramolecular chains are constructed of alkaline earth metal ions and Q[5] molecules alternating; the sizes of their ionic radiuses influence the interaction modes in the chain. The formation of the Ca-Q[5] polymer results in the partial coordination of Ca cations to the portals of adjacent Q[5] molecules due to the smaller ionic radiu...

To explore differences in coordination between alkali- and alkaline-earth-metal ions and cucurbit[n]urils, a water-soluble α,α',δ,δ'-tetramethylcucurbit[6]uril (TMeQ[6]) was used to synthesize a series of complexes and their supramolecular assemblies, based on the coordination of TMeQ[6] with alkali- and alkaline-earth-metal ions. The complexes and corresponding supramolecular assemblies were structurally characterized by single-crystal X-ray diffraction. Unlike cucurbituril (Q[6]), which formed the metal-Q[6] polymers based on the direct coordination of carbonyl oxygen atoms to the alkali-metal ions, TMeQ[6] formed metal-TMeQ[6] polymers based on the direct coordination of carbonyl oxygen atoms with the alkaline-earth-metal ions rather than the alkali-metal ions.

Using the achiral N,N'-bis(2-pyridylmethyl)-1,6-hexanediamine ligand bearing two end pyridyl groups as the source of conformational chirality, a novel type of TMeQ[6]-based helical polyrotaxane was prepared and characterized by X-ray crystallography and (1)H NMR spectroscopy. The chirality of the polyrotaxane was generated from twisting of the hexylidene of the N,N'-bis(2-pyridylmethyl)-1,6-hexanediamine "string" when bound within the hydrophobic cavity of TMeQ[6]. Two opposite chiral helical polyrotaxanes crystallize as a racemic compound.

Five crystals based on para-dicyclohexanocucurbit[6]uil (DCyHQ[6]) were synthesized and structurally characterized by single-crystal X-ray diffractions. They are {Dioxane@DCyHQ[6]}·18H2O (1), { [ Cu ( H 2 O ) 6 ] 2 DCyHQ [ 6 ] } 4 + · 2 SO 4 2 - · 10 H 2 O (2), { [ Zn ( H 2 O ) 6 ] 2 DCyHQ [ 6 ] } 4 + · 2 SO 4 2 - · 10 H 2 O (3), { [ Sr ( H 2 O ) 5 ] 2 DCyHQ [ 6 ] } 4 + · 5 Cl - · ( H 3 O ) + · 8 H 2 O (4), { [ Na ( H 2 O ) 4 ] 2 DCyHQ [ 6 ] } 2 + · 4 Br - · 2 ( H 3 O ) + · 14 H 2 O (5). The compound 1 which is a dioxane@DCyHQ[6] inclusion host–guest complex; the other three crystal structures of the compounds 2, 3 and 4 show supramolecular assemblies comprising of DCyHQ[6] and metal ions or their aqueous complexes through hydrogen bonding; while the crystal structure of the compound 5 shows a one-dimensional supramolecular polymer through direct coordination of sodium cations to the portal carbonyl oxygen atoms of the DCyHQ[6].

The 1:1 interaction of the diastereopure Schiff bases (1S,2S)-bis(acetylacetone)-cyclohexanediimine ( L 1 ) and (1R,2R)-bis(acetylacetone)cyclohexanediimine ( L 2 ) with CdI 2 yields the new helical metal coordination polymers [Cd L 1 I 2 ] n ( 1 ) and [Cd L 2 I 2 ] n ( 2 ). The respective X-ray structures, as expected, confirmed 1 and 2 to be enantiomeric, existing as right-handed ( P ) and left-handed ( M ) helical chains in which both L 1 and L 2 are formally present in their (unusual) uncharged ketoamine form, with the (protonated) amine nitrogens not coordinated. The Cd(II) centres in 1 and 2 display distorted tetrahedral coordination geometries being bound to two iodo ligands and two oxygen donor atoms from individual ketoamine domains belonging to different Schiff base ligands.

Four host–guest complexes, {(gI)@(CyH) 6 Q[6]}·3H 2 O ( 1 ), {(gIIH 2 ) 2+ @(CyH) 2 Q[6]}·2Cl − ·21H 2 O ( 2 ), {(gIII)@Q[6]}·27H 2 O ( 3 ), and {(gIVH) + @(CyH) 2 Q[6]}·Cl − ·13H 2 O ( 4 ), have been prepared from cyclohexanocucurbit[6]uril, {(CyH) 6 Q[6]}, symmetrical dicyclohexanocucurbit[6]uril {(CyH) 2 Q[6]}, and cucurbit[6]uril {Q[6]} as hosts, and four different guests, namely 2-phenyl-2 H -imidazole (gI), the HCl salt of N 1 , N 4 -bis(pyridin-3-ylmethyl)butane-1,4-diamine (gII), benzylamine (gIII), and the HCl salt of 4-(1 H -imidazolyl)phenol (gIV). Their crystal structures have been characterized by single-crystal X-ray diffraction analyses and revealed that these hosts can form supramolecular assemblies through iondipole interactions, hydrogen bonding, CH···π or NH···π interactions, and π···π stacking.

Four crystal structures of inclusion complexes of amino acid and cucurbit[n]uril have been synthesized and characterized by X-ray diffractions. The used four amino acids are l -Glutamate ( l -Glu), l -Tyrosine ( l -Tyr), l -Hisdine ( l -His), l -Leucine ( l -Leu) and the hosts are α,α′,δ,δ′-tetramethylcucurbit[6]uril (TMeQ[6]), the normal cucurbit[8]uril (Q[8]). The corresponding compounds based on the inclusion complexes of amino acid and cucurbit[n]uril have stoichiometry of { l -Glu@TMeQ[6]} + ·Cl − ·13H 2 O ( 1 ), {( l -Tyr) 2 @Q[8]}·27H 2 O ( 2 ), {( l -His) 2 @Q[8]}·19H 2 O ( 3 ) and {( l -Leu) 2 @Q[8]} 2+ ·2Cl − ·32H 2 O ( 4 ). The crystal structure of the compound 1 reveals that a l -Glu molecule is captured by a host TMeQ[6] with a 1:1 host:guest ratio. The crystal structures of compounds 2 , 3 and 4 show that all three inclusion complexes of l -Tyr@Q[8], l -His@Q[8] and l -Leu@Q[8] are in 1:2 host:guest ratio. The host Q[8] can include not only two aromatic moieties from two same guests (such as in the cases of 2 and 3 ) but also two alkyl chains of two l -Leu molecules (the case of 4 ).

The crystal structure of compound {3[Cd2(C36H36N24O12)]·10Cl·10(H2O)}·2Cl·39(H2O) (1) is reported. It consists of complexes of cucurbituril and cadmium cations formed through ion-dipole interactions, in which a novel two-dimensional network is created by the complexation of cucurbituril and cadmium ions. Binding constants determined from voltammetric data indicate that Cd2+ has a high binding affinity for Q[6] ( K Cd 2 + = 9.95 × 10 9 M - 2 by CV) and forms a 2:1 (M2+/Q[6]) complex.

Three host–guest complexes of methylsubstituted cucurbit[6]urils host and anthracene derivatives guests were synthesized and structurally characterized by single crystal X-ray diffractions and 1H NMR technique. The hosts are dodecamethylcucurbit[6]uril (DDMeQ[6]), α,α′,δ,δ′-tetramethylcucurbit[6]uril (TMeQ[6]), and hexa-methylsubstituted cucurbituril (HSMeQ[6]) made from 3a-methyl-glycoluril. The guests are 9,10-bis[N-(aminoethylene)aminomethyl]anthracene (AN1), 9,10-bis[N-(aminopropylene) aminomethyl]anthracene (AN2) and 9,10-bis[N-(aminobutylene)aminomethyl]anthracene (AN3). The crystal structures show the compounds 1–3 with stoichiometry of {DDMeQ[6]-AN1}2+2NO3−24H2O (1), {TMeQ[6]-AN2}2+4NO3− 2H3O+10H2O (2) and {2HSMeQ[6]-AN3}2+2Cl−25H2O (3) respectively, and the formation of an exclusion or inclusion host–guest complex is dependent on the length of the substituted alkyl chains on the anthracene.

Four molecular capsules based on three different cucurbit[5]urils, which are Dimethyl cucurbit[5]uril (DMeQ[5]), decamethylcucurbit[5]uril (Me 10 Q[5]) and the normal cucurbit[5]uril, were synthesized and structurally characterized by single-crystal X-ray diffractions. They are {[Gd 2 (H 2 O) 9 ][DMeQ[5]@Cl]} 5+ ·5Cl − ·13(H 2 O) ( 1 ), {[Nd 2 (H 2 O) 8 Cl][Me 10 Q[5]@Cl]} 4+ ·4Cl − ·9(H 2 O) ( 2 ), {K(H 2 O) 2 Cl·{[[Dy 2 (H 2 O) 6 Cl][Q [5]@Cl]} 2 } 8+ ·2{[Dy 2 (H 2 O) 7 Cl][Q[5]@Cl]} 4+ ·16Cl − ·44(H 2 O) ( 3 ) and 2{[Y 2 (H 2 O) 8 ][Me 10 Q[5]@Cl]} 5+ ·10Cl − ·48(H 2 O) ( 4 ). In the crystal structure of these compounds, molecular capsules included a Cl − anion and lidded with lanthanide cations were observed.

Four molecular capsules based on three methyl-substituted cucurbit[5]urils, which are α,β,δ-hexamethyl cucurbit[5]uril (α,β,δ-HMeQ[5]), decamethylcucurbit[5]uril (Me10Q[5]) and a pentamethylcucurbit[5]uril constructed of a monomethyl-glycouril (PMeQ[5]), were synthesized and structurally characterized by single crystal X-ray diffractions. They are {[α,β,δ-HMeQ[5]@Cl][Sr(H2O)2]2}3+3·Cl−·13(H2O) (1), {[α,β,δ-HMeQ[5]@(NO3)][Sr(NO3)(H2O)]2}+[NO3]−HNO3·4(H2O) (2), {[Me10Q[5]@(NO3)][Sr(NO3)(H2O)]2}+(NO3)−8(H2O) (3) and {[PMeQ[5]@Cl][Sr(H2O)2]2}3+3·Cl−·22(H2O) (4). In the crystal structure of these compounds, molecular capsules included a Cl− or a NO 3 - anion and lidded with strontium cations were observed.

Three new alkyl-substituted cucurbit[6]urils, symmetrical tetracyclopentano cucurbit[6]uril {TCyPQ[6]}, meta-tricyclopentano cucurbit[6]uril {m-TriCyPQ[6]} and meta-dicyclopentano cucurbit[6]uril {m-(CyP)2Q[6]}, were synthesized by using the controlled synthesis utilizing the readily available dimer of the unsubstituted glycouril, diether of cyclopentano glycoluril and the unsubstituted glycouril. These partial cyclopentano-substituted cucurbit[6]urils were characterized by single-crystal X-ray diffractions. In the crystal structure of compounds 2{TCyPQ[6]}·57H2O (1) and {m-TriCyPQ[6]}·23H2O (2), both of Q[6]s formed a molecular capsule included water molecules, and the capsules assembled one-dimensional supramolecular chains through the hydrogen bonding. In the crystal structure of compound 2{m-(CyP)2Q[6]}·(HV)2+·4Cl−·2(H3O)+·44H2O (3), a dumbbell shape host–guest inclusion complex N,N-dihexyl-4,4′-bipyridinium(HV2+) with m-(CyP)2Q[6] was formed, the m-(CyP)2Q[6] host selectively included the alkyl moiety of the guest through the hydrophobic cavity interaction and the ion-dipole interaction.