Interplay of Supramolecular Chemistry and Photochemistry with Palladium-Catalyzed Ethylene Polymerization

Metal–metal cooperativity effects have been extensively explored in olefin polymerization,along with the design and preparation of many binuclear transition metal catalysts.However,their synthesis and the tuning of metal–metal distance are complicated and time-consuming.In this contribution,a supramolecular chemistry strategy was used to construct multinuclear olefin polymerization catalysts.Urea functional groups were installed into severalα-diimine palladium catalysts to enable hydrogenbonding-induced self-assembly.

Cellulose-based hydrogels regulated by supramolecular chemistry

Supramolecular hydrogels based on cellulose attract increasing attention because of their novel structures and broad potential applications.In this review,hydrogels composed of cellulose are summarized according to category of supramolecular interactions in the networks including hydrogen bonds,electrostatic interactions,host-guest interactions,and others.Supramolecular cellulose-based hydrogels constructed by noncovalent bonding usually exhibit environmental friendliness,designing flexibility and diverse functions,and their properties are variable with incorporating different interactions in hydrogel networks.Moreover,with proper structures and networks,the supramolecular cellulose-based hydrogels are adaptable in diverse fields of research and practical applications,such as self-healing,shape memory,drug delivery,and some other renewable/sustainable materials.The future developments and challenges of the supramolecular hydrogels based on cellulose are discussed as well.

Photoactive donor-acceptor conjugated macrocycles:New opportunities for supramolecular chemistry

The design and synthesis of photoactive macrocyclic molecules continue to attract attention because such species play important roles in supramolecular chemistry as well as photoelectronic applications.Donoracceptor(D-A)conjugated macrocycles are an emerging class of photoactive molecules due to their D-A conjugated structural characteristics and tunable optical properties.In addition,the well-defined cavities in such D-A macrocycles endow them with versatile host-guest properties.In this review,we provide a comprehensive summary of D-A conjugated macrocycle chemistry,detailing recent progress in the area of synthetic methods,optical properties,host-guest chemistry and applications of the underlying chemistry to chemical sensors,bioimaging and photoelectronic devices.Our objective is to provide not only a review of the fundamental findings,but also to outline future research directions where D-A conjugated macrocycles and their constructs may have a role to play.

Syntheses and Crystal Structures of Two New Supramolecular Architectures Constructed from the Main Group Metal Chloride and Protonated 2-(3-Pyridyl)benzimidazole

The reactions of SbCl3 and HgCl2 with 2-（3-pyridyl）benzimidazole （PyBIm） in solution acidified with HCl have been investigated. The PyBIm ligands are protonated into 2-（3-pyridinio）benzimidazolium （H2PyBIm） cations and the corresponding metal ions are bonded with chloride atoms into coordination anions, forming two new coordination compounds, namely, （H2PyBIm）（SbCl5） 1 and （H2PyBIm）2（Hg2Cl8） 2. Both compounds were characterized by X-ray crystallography. Crystal data for 1： triclinic, space group P1^- with a = 5.7030（7）, b = 9.0625（11）, c = 16.5929（18） A, α = 91.808（7）°, β = 93.234（6）, γ = 99.216（7）°, C12H11N3SbCl5, Mr = 496.24, V = 844.44（17） A^3, Z = 2, Dc = 1.952 g/cm^3, μ（MoKα） = 2.419 mm^-1, F（000） = 480, the final R = 0.0496 and wR = 0.1382 for 3433 observed reflections （I 〉 2σ（I））. Crystal data for 2： monoclinic, space group P21/c with a = 7.8061（5）, b = 15.8127（9）, c = 12.2435（9） , β = 91.955（4）o, C24H22N6Hg2Cl8, Mr = 1079.26, V = 1510.40（17） 3, Z = 2, Dc = 2.373 g/cm3, μ（MoKα） = 10.889 mm-1, F（000） = 1008, the final R = 0.0293 and wR = 0.0562 for 2854 observed reflections （I 〉 2σ（I））. X-ray diffraction analysis reveals that the antimony（III） is five-coordinated, exhibiting a slightly distorted square-pyramidal coordination geometry; while in 2, a dimeric [Hg2Cl8]^4-anion consists of two trigonal bipyramids sharing two common edges. The organic cations and coordination anions are connected into a one-dimensional belt and a two-dimensional sheet through N-H···Cl hydrogen bonding interactions in compounds 1 and 2, respectively; both are further aggregated into 3D frameworks by strong π-π contacts.

Gear-like array of (H_2O)_(12) as building blocks in one-dimensional supramolecular assembly

The preparation and crystal structure of complex Co（Hsae）2·2H2O （1, H2sae = N-salicylidene-2-iminoethanol） are reported. X- ray analysis revealed that every six Co（Hsae）2 forms a cyclic chip and every 12 water forms a novel gear-like cluster. Acting as building blocks, the gear-like water cluster and complex chip are connected in A-B fashion and extend into one-dimensional supramolecular chain. Hydrogen bond is the primary bridging force in the formation of supramolecular framework.

Supramolecular Self-assembly and Functionalization of Porphyrin-based Systems

Porphyrins are abundant in nature. They have been frequently employed as building blocks in the construction of nanoarchitectures and functional supramolecular systems. Recently, a series of novel porphyrin molecules including small molecules and polymers have been originally designed and synthesized with the aim of producing nanostructures with controllable-growth and materials with high-performance. Literature coverage is through 2004-2012. This review gives a full summary of related studies in our group.

A Novel Layered Supramolecular Network Constructed from Heterohexanuclear La(Ⅲ)-Cr(Ⅲ) Complexes by Hydrogen Bonding

The complex [La2(m-ox){Cr(bipy)(m-ox)(ox)}4(H2O)6]?2.3(H2O) (C58H68.6N8O54.3Cr4La2) 1 has been obtained from the reaction of La(Ⅲ) salt with [Cr(bipy)(ox)2]- (bipy = 2,2?bipyridine and ox = oxalate dianion) building blocks in aqueous solution and structurally characterized by X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 10.740(2), b = 17.943(4), c = 22.388(5) ? V = 4314(2) 3, Z = 2, Mr = 2232.43, Dc = 1.719 g/cm3, F(000) = 2234, m(MoKa) = 1.565 cm-1 and T = 293(2) K. With the use of 5202 observed reflections (I > 2s(I)), the structure was refined to R = 0.0742 and wR = 0.1554. Complex 1 shows a two-dimensional open network constructed from hexanuclear {La2Cr4} units through the intermolecular hydrogen interactions.

Supramolecular Architecture from the Self-assembly of One-dimensionalCoordination Polymers and Hydrogen Bonds

The novel one-dimensional coordination polymer {[Cu(L)2(H2O)]?2BF4?6H2O}∞ [1, L=1,2-bis(4-pyridinecarboxamido)ethane] was synthesized as single crystals and characterized by means of X-ray diffraction analysis, elemental analysis, IR spectroscopy and TG measurement. Structure 1 consists of looped chains. In addition, linked by hydrogen bonds, the one-dimensional chains were transformed into three-dimensional framework, which shows channels filled with anions and uncoordinated water molecules.

Supramolecular flow chemistry: Construction of multiscale supramolecular assemblies by micro/nanofluidic techniques

The rapid and precise fabrication of multiscale supramolecular assemblies using micro/nanofluidic techniques has emerged as a dynamic area of research in supramolecular chemistry, materials chemistry, and organic chemistry. This review summarizes the application of micro/nanofluidic techniques in constructing supramolecular assemblies, including nanoscale supramolecular assemblies such as macrocycles and cages, microscale supramolecular assemblies such as metal organic frameworks (MOFs) and covalent organic frameworks (COFs), and macroscale supramolecular assemblies such as supramolecular hydrogels. Compared to conventional synthesis methods, micro/nanofluidic techniques for the production of supramolecular assemblies have significant advantages, including enhanced safety, high reaction rates, improved selectivity/yield, and scalability. Additionally, micro/nanofluidic systems facilitate the creation of precisely controllable micro/nanoconfined environments, allowing for a unique flow behavior that improves our understanding of the supramolecular self-assembly process. Such systems may also lead to the development of novel supramolecular assemblies that differ from those generated via traditional methods.

Improvement of hybridization signals of gold label silver stain gene detection

The factors that influence the colorimetric gene detection of gold label silver stain and improve the detection signals were studied. The influence of amino DNA probes and thiol DNA modified gold nanoparticles was investigated based on a sandwich hybridization system. An increase in amino probe concentration brought about an increase in hybridization signal which reached a threshold corresponding to the saturated concentration of amino probes bounded onto a glass slide surface. Since the steric hindrance effect of nanoparticles was dominant over the influence of a surface area, the bigger gold nanoparticles led to weaker hybridization signals. The hybridization efficiency enhanced significantly with the increase of the thiol DNA modified nanoparticle concentrations. Experimental results showed that 125 μmol/L of the amino DNA probe concentration, 15 nm of the gold nanoparticle diameter, and 4.07 nmol/L of the thiol DNA modified gold nanoparticle concentration were optimal for the detection system. The hybridization signals can be improved remarkably by choosing optimal hybridization conditions.

A Colorimetric Receptor Based on SchiffoBase Bearing Azo-Phenolic Hydroxy Group

A novel N-（2-hydroxy-5-chlorodibenzophenone）-N＇-[2-hydroxy-5-azophenyl-benzaldehyde]- 1,2-diaminobenzene receptor has been synthesized by simple steps with good yields. The anion recognition properties were studied by ultraviolet-visible spectroscopy. The results showed that the receptor had a higher affinity to F-, AcO-, and H2PO4-, but no evident binding with Cl-, Br-, and l-. Upon addition of the three former anions to the receptors in DMSO, the solution exhibited an obvious color change from colorless to yellow, which could be observed by the naked eye, thus the receptor could act as a fluoride ion sensor even in the presence of other halide ions. The UV-Vis data indicates that a 1：1 stoichiometric complex is formed through hydrogen bonding interactions between receptor and anions.

The Paramagnetic 2D Chiral-porous Polymer of L-Phenylalanine and Manganese

Mn(L-Phe)2稨2O]n (Phe=phenylalanine) with a single stranded coordination poly- mer has been synthesized by self-assembly of manganese salt and phenylalanine and characterized by X-ray single-crystal diffraction method. The complex crystallizes in the orthorhombic, space group P212121 with a = 6.0911(1), b = 10.3642(1), c = 30.4321(7) ? V = 1921.16(6) ?, Z = 4, Dc = 1.387 g/cm3, C18H22N2O5Mn, Mr = 401.32, F(000) = 836 and m(MoKa) = 0.717 mm-1. The final R = 0.0614 and wR = 0.1412 for 2291 observed reflections with I > 2s(I). The magnetic behavior study shows that there exist super-exchange antiferromagnetic interactions between the magnetic centers through the effective exchange pathway of the carboxylate group.

Recent progress in supramolecular chiral photochemistry

Chiral photochemistry appears to be a highly challenging topic and still very much in its infancy, especially if comparing to its well-developed thermochemical counterpart.Significant efforts have been devoted in order to improve stereoselectivity of chiral photoreactions,among which,the supramolecular strategy proven the most promising.The present review,motivated by the rapid progress in the supramolecular chiral photochemistry,concentrates on advancements achieved mainly in the last decade.The features and advantages of supramolecular chiral photochemistry are exemplified by representative photoreactions in terms of the chiral hosts/assemblies.

Supramolecular Radical Switches Regulated by Host-Guest Chemistry

Water-soluble thermal initiators are important radical sources to be applied in various fields.However,the uncontrolled radical generation from the high sensitivity of initiators may cause disadvantages in the applications.Here,we present a series of supramolecular radical switches regulated by the host-guest chemistry between initiators and cucurbit[8]uril(CB[8]).Thermal initiators(VA-044,VA-056,VA-057)can be spontaneously encapsulated into the cavity of CB[8]to“turn off”their radical-generation ability.Their activity will instantaneously“turn on”in the presence of other competitors such as 1-adamantylamine(ADA).Further,we demonstrated the free radical polymerization of N-isopropylacrylamide using initiators,inhibiting its activity by binding with CB[8]and initiating reaction by adding ADA.These novel supramolecular radical switches provide a facile strategy to control the generation of free radicals in a“plug-and-play”manner,which may arouse research interests in polymerization,catalysis,and the biomedical field.

Synthesis and Structure of an Octopus-like Octapropargyl Tetra-iso-butyl-resorcin[4]arene

Treatment of tetra-iso-butyl-resorcin[4]arene 1 with propargyl bromide in the presence of K2CO3 as base gave an octopus-like octapropargyl tetra-iso-butyl-resorcin[4]arene 2 （C68H72O8, Mr = 1017.26） in a quantitative yield. Single-crystal structure of 2 was determined by X-ray crystallography. 2 crystallizes in the monoclinic system, space group P21/n with a =13.3247（6）, b = 24.7929（11）, c = 19.1810（9）A°, β = 109.272（1）°, V= 5981.5（5） A°^3, Dc = 1.130g/cm^3,μ = 0.073 mm^-1, F（000） = 2176 and Z = 4. Overall structure of 2 reveals an octopus-like resorcinarene with eight propargyl groups in different directions. The resorcinarene adopts the boat conformation where the iso-butyl residues act as four-legged piano stool. The two opposite aryl rings of the macrocyclic framework are almost coplanar, and the two others facing each other are perpendicular to this plane.

1D Ferromagnetic Interaction of 2-Iodo Nitronyl Nitroxide Radical Confirmed by Spin Density Calculation

A supramolecular 1D ferromagnetic system was studied experimentally as well as theoretically.Hybrid density functional theory（DFT） calculations were based on the X-ray analysis.The results of DFT calculations and McConnell mechanism have contributed to the understanding of the factors governing the exchange coupling of magnetism in the crystal packing.Both the experimental evidence and theoretical calculation indicate that spin density in 2-iodo nitronyl nitroxide（INN） radicals confirms 1D ferromagnetic chain with inter-chain antiferromagnetic interaction.

Hydrogen-bonded 1D and 2D Assemblies of Tetraiso-butyl-resorcin[4]arene in the Crystalline State

X-ray crystal structures of co-crystals involving tetra-iso-butyl-resorcin[4]arene 1 with both acetone and acetonitrile solvents were reported. The component 1?2(CH3)2CO 2 assembles such that the resorcin[4]arene adopts a C2v conformation and the acetone serves as hydrogen bond acceptors, forming a 1D hydrogen-bonded polymer. 2 (C50H68O10) crystallizes in the triclinic, space group P1 with a = 10.0440(7), b = 13.7498(9), c = 17.6374(12) ?, α = 77.726(2), β = 86.733(2), γ = 88.634(2)o, V = 2376.1(3) ?3, Dc = 1.159 g/cm3, and Z = 2. The assembly process of component 1?2CH3CN?H2O 3 yields a 2D hydrogen-bonded polymer formed by intermolecular hydrogen bonds between resorcin[4]arene and water molecules. In the case of component 3, the acetonitrile molecule serves as guest inside the bowl of resorcin[4]arene host. 3 (C48H64N2O9) crystallizes in the monoclinic, space group P2/n with a = 13.7570(18), b = 9.0961(12), c = 19.453(3) ?, β = 103.017(3)o, V = 2371.7(5) ?3, Dc = 1.138 g/cm3, and Z = 2.

Co-crystallization of Resorcin[4]arene Tetracarboxylic Acid with Triethylamine:Synthesis and Crystal Structure

Treatment of resorcin[4]arene tetracarboxylic acid 1 with triethylamine in the presence of Co（CH3COO）2·4H2O and 4,4 -bipyridine gave a co-crystallization 14-·4Et3NH＋（C32H20O164-·4Et3NH＋,Mr=1069.27） from ethanol and water.The compound was structurally determined by single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/n,with a=8.1763（18）,b=12.913（3）,c=28.724（7） ,β=97.574（4）o,V=3006.3（12） 3,Z=2,Dc=1.181 g/cm3,F（000）=1152,Rint=0.0275,T=293（2） K,μ=0.086 mm-1,the final R=0.0634 and wR = 0.1752 for 5082 observed reflections with I 〉 2σ（I）. The co-crystallization is very stable at room temperature. Possibly, a network of N-H…O（=C） plays an important role in the structure. Meanwhile, the compound emits a weak cyan luminescence with peak maximum band at 458 nm.

A New Maleamide Bridged Carbazole Chromogenic-sensor Based on Proton Transfer Signaling Mode

A Maleamide bridged carbazole receptor was designed and synthesized, the interactions between the receptor and anions, such as Ac-, H2PO4-, OH-, F-, Cl-, Br- and I- in DMSO were investigated by UV-Vis spectroscopy and 1H NMR titration. The results of UV-Vis spectral studies indicate that interactions existed between receptor and anions, which induced remarkable color changes. The 1H NMR titration indicated amide moiety of the receptor was deprontonated first when a small quantity of anions such as Ac-, H2PO4-, F- were added; however, the carbazole N―H was gradually deprontonated upon the addition of anions.

Synthesis of Calix[4]resorcinarene Amide Derivatives

Three different synthetic routes were developed to introduce carbamoyloxy functional groups at the upper periphery of two calix[4]resorcinarenes. By treating activated esters 2a-b with excess corresponding amine such as 3-(dimethylamino)propylamine 3, -phenethylamine 4 and triethylenetetramine 5, six amide derivatives 6a^8b were obtained in high yield (Route 1). The pyridine-linked amide derivatives 9a-b were prepared by using acid chloride intermediate (Route 2). The amide derivatives 10a-b were obtained in moderate yields by direct alkylation of phenolic hydroxyl groups of 1a-b with N,N-dipropylchloroacetoamide in the presence of K2CO3/KI in acetone (Route 3).