Supramolecular Chemistry: Host–Guest Molecular Complexes

In recent times, researchers have emphasized practical approaches for capturing coordinated and selective guest entrap. The physisorbed nanoporous supramolecular complexes have been widely used to restrain various guest species on compact supporting surfaces. The host–guest (HG) interactions in two-dimensional (2D) permeable porous linkages are growing expeditiously due to their future applications in biocatalysis, separation technology, or nanoscale patterning. The different crystal-like nanoporous network has been acquired to enclose and trap guest molecules of various dimensions and contours. The host centers have been lumped together via noncovalent interactions (such as hydrogen bonds, van der Waals (vdW) interactions, or coordinate bonds). In this review article, we enlighten and elucidate recent progress in HG chemistry, explored via scanning tunneling microscopy (STM). We summarize the synthesis, design, and characterization of typical HG structural design examined on various substrates, under ambient surroundings at the liquid-solid (LS) interface, or during ultrahigh vacuum (UHV). We emphasize isoreticular complexes, vibrant HG coordination, or hosts functional cavities responsive to the applied stimulus. Finally, we critically discuss the significant challenges in advancing this developing electrochemical field.     

Two Supramolecular Nickel(II) Complexes: Syntheses,Crystal Structures and Solvent Effects

Two nickel(II) complexes, namely {[NiL(MeOH)(μ‐OAc)]₂Ni} · 2CH₂Cl₂ · 2MeOH ( 1 ) and {[NiL(EtOH)(μ‐OAc)]₂Ni} · 2EtOH ( 2 ) {H₂L = 5, 5′‐dimethoxy‐2, 2′‐[(ethylene)dioxybis(nitrilomethylidyne)]diphenol}, were synthesized and structurally characterized. Two trinuclear Ni^II complexes are both hexacoordinate around the central Ni^II atoms, showing octahedral coordination arrangements, and each complex comprises three divalent Ni^II atoms, two deprotonated L^2– ligands, in which four μ‐phenoxo oxygen atoms forming two [NiL(X)] (X = MeOH or EtOH) units, and coordinated and non‐coordinated solvent molecules. Complex 1 exhibits a 2D supramolecular network through intermolecular O–H ··· O, C–H ··· O and C–H ··· π interactions, whereas complex 2 forms an infinite 1D chain by intermolecular C–H ··· O hydrogen bonding interactions.     

三嗪吡唑类配位超分子化合物的合成、结构及光催化活性

在水和乙醇的混合体系中合成了2个配位化合物[Co(Bpz*ea T)(H2O)3]·2H2BTC·2H2O(1)和[Cu(Bpz*ea T)(H2O)3]·2H2BTC·CH3CH2OH·H2O(2)[Bpz*ea T=2,4-二(3,5-二甲基吡唑)-6-二乙胺基-1,3,5-三嗪;H3BTC=均苯三甲酸].通过元素分析、红外光谱、紫外光谱、热重分析、X射线粉末衍射以及X射线单晶衍射方法对配合物进行了表征.结构分析表明,配合物1和2的中心金属均为六配位,形成扭曲的八面体构型.通过分子间氢键的作用,配合物1和2分别被连接成三维和二维的超分子结构.此外,对2个配合物的光催化活性进行了研究.     

Hydrothermal Syntheses, Supramolecular Structures and the Third-order Non-linear Optical Properties of Three Copper(I) Halide Amine Complexes Connected via Secondary Bonding Interactions

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Syntheses, Structures and Luminescent Property of Two Supramolecular Complexes Containing N-P-Acetamidobenzenesulfonyl-glycine Acid Ligand

Making use of N-P-acetamidobenzenesulfonyl-glycine acid （abbreviated as abglyH2）,two transitional metal complexes [Zn（abglyH）（phen）2]ClO4·H2O （1） and Co（abglyH）2（bipy）2（H2O）2 （2） （phen = 1,10-phenanthroline,bipy = 4,4＇-bipyridine） have been synthesized under mild conditions and characterized by IR,elemental analysis and X-ray diffraction analysis. Complex 1 is a monomeric compound which is further assembled by intermolecular hydrogen bonds and π-π interaction into a 2-D supramolecular network. Complex 2 is also a monomeric compound and further connected by intermolecular hydrogen bonds to form a 2-D supramolecular network. Fluorescent analysis shows that complex 1 has an emissive maximum at 364 nm in the solution state at room temperature.     

Syntheses and Crystal Structures of Mononuclear and Binuclear Lanthanide Halide Complexes with Diglyme

Two types of isostructural complexes of lanthanide chlorides with diglyme have been synthesized. These are mononuclear molecular complexes [LnCl₃(diglyme)(THF)] (Ln = Eu ( 1 ), Gd ( 2 ), Dy ( 3 ), Er ( 4 ), Yb ( 5 ); diglyme = diethylen glycol dimethyl ether) and binuclear molecular complexes [LnCl₃(diglyme)]₂ (Ln = Dy ( 3d ), Er ( 4d ), Yb ( 5d )). Complex 1 was obtained by the reaction of [EuCl₃(DME)₂] with diglyme in THF. The complexes 2 – 5 and 3d – 5d resulted from reactions of LnCl₃·6H₂O, (CH₃)₃SiCl and diglyme in THF. The mononuclear complexes 2 – 5 crystallized directly from the solutions where the reactions of lanthanide compounds with diglyme took place. Recrystallizations of the powder products of the same reactions from dichloromethane resulted in the binuclear complexes 3d – 5d . Reactions of lanthanide bromide hydrates, (CH₃)₃SiBr and diglyme in THF achieved mononuclear molecular complexes [LnBr₃(diglyme)(L)] (Ln = Gd, L = H₂O ( 6 ); Ln = Ho, L = THF ( 7 )). Crystals of 6 and 7 were grown by recrystallization from dichloromethane. The lanthanide atoms (Ln = Eu–Yb) are seven‐coordinated in a distorted pentagonal bipyramidal fashion in all reported complexes, 1 – 7 and 3d – 5d . Four oxygen atoms and three halide ions are coordinated to lanthanide atoms in 1 – 7 , [LnX₃(diglyme)(L)]. Four chloride ions, two bridging and two nonbridging, and three oxygen atoms are coordinated to lanthanide atoms in 3d – 5d , [LnCl₃(diglyme)]₂.     

Syntheses,Structures and Luminescent Properties of Metal Halide Complexes Containing 2,3‐Diphenylquinoxaline

The reaction of CuI with 2,3‐diphenylquinoxaline ( L ) in 1:1 mole proportion in CH₃CN/THF afforded the dinuclear complex [CuI( L )]₂, 1 , whereas the reactions of MX₂ (M = Cu; Hg) with L in 1:2 mole proportion in CH₃OH gave the mononuclear complexes CuX₂( L )₂ (X = Cl, 2 ; Br, 3 ) and HgX₂( L )₂ (X = Cl, 4 ; Br, 5 ). Formulations of all the complexes were determined on the basis of X‐ray crystallography, elemental, IR‐ and emission spectroscopy. X‐ray examination revealed that complex 1 forms the μ,μ‐iodobridged dimer with distorted trigonal planar geometry through coordination of L ligand by one nitrogen atom to the Cu(I) center. The metal centers of complexes 2 and 3 form distorted square planar geometry while those of complexes 4 and 5 form linear geometry. The molecules of these complexes are interlinked through C‐H—π and/or π‐π stacking and anion—π interactions that form the packed structure. All the complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π r? π* transitions.     

Influence of Substitution on the Supramolecular Chemistry of Cycloparaphenylene-Fullerene Complexes

We present a comprehensive host-guest study of four substituted and unsubstituted [10]cycloparaphenylenes with the fullerenes C₆₀ and C₇₀. Within this study, the influence on the complexation behavior was investigated experimentally and computationally. Due to the increased steric demand the substitution on the nanohoop results in an energetic penalty, which could be partially compensated by additional substituent-fullerene interactions. These attractive interactions are intensified in the C₇₀ complexes and with an increased degree of substitution. For the computational investigation conformer ensembles were taken into account, providing reliable structures with Boltzmann weighted energies. An analysis of the noncovalent interactions elucidated the origin of the enhanced substituent-C₇₀ interaction. The ellipsoid fullerene C₇₀ can be considered as a π-extended version of C₆₀, which is able to increase the attractive van der Waals interactions within these supramolecular complexes.     

Beryllium Halide Complexes Incorporating Neutral or Anionic Ligands: Potential Precursors for Beryllium Chemistry

Reactions of the beryllium dihalide complexes [BeX₂(OEt₂)₂] (X=Br or I) with N,N,N′,N′‐tetramethylethylenediamine (TMEDA), a series of diazabutadienes, or bis(diphenylphosphino)methylene (DPPM) have yielded the chelated complexes, [BeX₂(TMEDA)], [BeX₂{(RN=CH)₂}] (R=tBu, mesityl (Mes), 2,6‐diethylphenyl (Dep) or 2,6‐diisopropylphenyl (Dip)), and the non‐chelated system, [BeI₂(κ¹‐P‐DPPM)₂]. Reactions of lithium or potassium salts of a variety of β‐diketiminates have given both three‐coordinate complexes, [{HC(RCNAr)₂}BeX] (R=H or Me; Ar=Mes, Dep or Dip; X=Br or I); and four‐coordinate systems, [{HC(MeCNPh)₂}BeBr(OEt₂)] and [{HC(MeCNDip)(MeCNC₂H₄NMe₂}BeI]. Alkali metal salts of ketiminate, guanidinate, boryl/phosphinosilyl amide, or terphenyl ligands, lead to dimeric [{BeI{μ‐[(OCMe)(DipNCMe)]CH}}₂], and monomeric [{iPr₂NC(NMes)₂}BeI(OEt₂)], [κ²‐N,P‐{(HCNDip)₂B}(PPh₂SiMe₂)NBeI(OEt₂)] and [{C₆H₃Ph₂‐2,6}BeBr(OEt₂)], respectively. Compound [{HC(MeCNPh)₂}BeBr(OEt₂)] undergoes a Schlenk redistribution reaction in solution, affording the homoleptic complex, [{HC(MeCNPh)₂}₂Be]. The majority of the prepared complexes have been characterized by X‐ray crystallography and multi‐nuclear NMR spectroscopy. The structures and stability of the complexes are discussed, as is their potential for use as precursors in poorly developed low oxidation state beryllium chemistry.     

两个基于羧基-水分子链构筑的超分子镉配合物的合成、晶体结构和荧光性质

以5-甲基-3-吡唑甲酸(H2MPCA)为主配体,在螯合配体菲咯琳(phen)或2,2′-联吡啶(2,2′-bpy)的存在条件下,与醋酸镉在常温下反应得到2个基于氢键构筑的羧基-水分子链的超分子化合物,[Cd(HMPCA)2(2,2′-bpy)]·2H2O(1)和[Cd(HMPCA)2(phen)]·2.5H2O(2),并通过元素分析、红外光谱、热重分析、X-射线衍射等对其结构进行了表征。结构分析表明,在化合物1和2中,单核镉的配合物和游离水分子通过氢键及π…π堆积作用形成了三维超分子结构,在此过程中,游离水和羧基构筑的链状水分子簇起着非常重要的作用。此外,我们还研究了化合物1和2的热重和荧光性质。     

两个基于羧基-水分子链构筑的超分子镉配合物的合成、晶体结构和荧光性质

以5甲基-3-吡唑甲酸(H₂MPCA)为主配体,在螯合配体菲咯啉(phen)或2,2'-联吡啶(2,2'-bpy)的存在条件下,与醋酸镉在常温下反应得到2个基于氢键构筑的羧基-水分子链的超分子化合物,[Cd(HMPCA)₂(2,2'-bpy)]·2H₂O(1)和[Cd(HMPCA)₂(phen)]·2.5H₂O(2),并通过元素分析、红外光谱、热重分析、X-射线衍射等对其结构进行了表征.结构分析表明,在化合物1和2中,单核镉的配合物和游离水分子通过氢键及π…π堆积作用形成了三维超分子结构,在此过程中,游离水和羧基构筑的链状水分子簇起着非常重要的作用.此外,我们还研究了化合物1和2的热重和荧光性质.     

Structural Flexibility of Metal Chelate Complexes and Its Relation to Supramolecular Chemistry

Crystal structures of metal chelate and related complexes in the Cambridge Structural Database have been analyzed, with respect to their use as components in supramolecular metal-organic compounds. In β-diketonate complexes, the distribution of angles between ligands is relatively broad; other ligands, such as 2,2′-bipyridine, yield significantly narrower distributions. According to the principle of structure correlation, these distributions reflect the ease of distorting the various families of complexes. A comparison through density functional theory calculations also indicates that angular distortions require significantly less energy for M(β-diketonate)₃ than for M(2,2′-bipyridine)₃. The differences are likely to affect the construction of supramolecular systems from different combinations of metals and ligands, including the likelihood that the desired structures will be obtained.     

Supramolecular Polymer Chemistry: Past,Present, and Future

Chinese Journal of Polymer Science -     

Syntheses of Segmental Heteroleptic Ligands for the Self-Assembly of Heteronuclear Helical Supramolecular Complexes

The development of a modified Phillips reaction allows the synthesis of complicated heteroleptic ligands based on pyridine and 1H-benzimidazole moieties. The key-step formation of aromatic 1H-benzimidazole rings from N-(2-nitroaryl)arenecarboxamides significantly improves the possibilities of the classical intermolecular Phillips reactions and can be applied to the synthesis of large oligo-multidentate units. Segmental heteroleptic ligands containing two different bidentate coordinating units (see 14 ) or bidentate and terdentate sites connected by ‘diphenylmethane’ ( = methylenebis(phenylene)) spacers (see 15 and 16 ) were obtained in fair to good yield by using multistep syntheses following this strategy. Heterotrileptic ligands (bidentate-terdentate-bidentate, see 19 and 20 ; terdentate-terdentate-terdentate, see 23 ) requiring the simultaneous formation of four 1H-benzimidazole rings in one step were prepared and demonstrate the extended possibilities of this methodology. Data are presented to show that the milder conditions used for this modified Phillips reaction together with its flexibility are essential for the development of ligands adapted for the self-assembly of heteronuclear helical complexes.     

Two New Three-dimensional Supramolecular Complexes with 5-Carboxyl-1-carboxymethyl-2-oxidopyridinium: Syntheses and Crystal Structures

Two new supramolecular complexes [MnL(H2O) 4](1) and [ZnL(H2O) 5]·0.25H2O(2) (H2L = 5-carboxy-1-carboxymethyl-2-oxidopyridinium) have been synthesized and structurally characterized by elemental analysis,IR and X-ray single-crystal structure determination. Complex 1 crystallizes in the monoclinic system,space group P21/n with a = 5.1537(2) ,b = 21.2008(9) ,c = 10.9727(4) ,β = 99.182(2) °,V = 1183.54(8) 3,C8H13MnNO9,Mr = 322.13,Dc = 1.808,Z = 4,F(000) = 660,μ = 1.160,R = 0.0372 and wR = 0.0750 for 2217 observed reflections(I > 2σ(I)) . Complex 2 crystallizes in the triclinic system,space group P1 with a = 7.730(2) ,b = 8.030(2) ,c = 11.400(2) ,α = 104.27(3) ,β = 92.93(3) ,γ = 102.67(3) °,V = 664.9(2) 3,C8H15.5ZnNO10.25,Mr = 355.08,Dc = 1.774,Z = 2,F(000) = 365,μ = 1.899,R = 0.0243 and wR = 0.0695 for 2759 observed reflections(I > 2σ(I)) . Their thermal properties have been studied.     

Hydrothermal Syntheses,Supramolecular Structures and the Third—order Non—linear Optical Properties of Three Copper（Ⅰ）Halide Amine Complexes Connected via Secondary Bonding Interactions

The hydrothermal reactions of CuI,KI and bidentate amines [1,10-phenanthroline(phen) or ethylenediamine (en)]gave the three copper (Ⅰ）halide compounds,Cu3I3(phen)2(1),CuI(phen)2(2) and [Cu(en)2][CuI2](3),which were struc-turally characterized via single-crystal X-ray diffraction stud-ies,Hydrogen bonds and π-π interactions are the most remarkable structural features of the title compounds .All can be described as higher-dimensional supramolecular compounds connected via these secondary bondings,Moreover,the title compounds were characterized by elemental analyses,IR spectra and TGA analyses,The third-order non-linear optical properties of the title compounds were also investigated and all exhibit nicer non-linear absorption and self-focusing performance.     

基于2-氨基吡啶的两个簇基超分子化合物的合成、结构及催化性能

以磷钼酸、2-氨基吡啶、五氧化二钒、氯化锌和氯化镍等为主要原料,采用水热方法合成了2个簇基超分子化合物[H₃PMo₁₂O₄₀]₂[C₅H₆N₂]₆(1)和[H₂PMo₁₂V₂O₄₂][C₅H₆N₂]₅·3H₂O(2)(C₅H₆N₂=2-氨基吡啶).通过元素分析、红外光谱、紫外-可见光谱、X射线光电子能谱、热重分析、X射线单晶衍射及X射线粉末衍射等手段对化合物进行了结构表征.结构分析显示,簇单元不同的2个超分子化合物以各自独特的堆积方式形成三维超分子网络.利用苯乙烯的环氧化反应研究了2个化合物的催化性能.