β-环糊精-烟酸超分子体系的合成、表征及结构

合成了β-环糊精-烟酸超分子体系,用差热分析和核磁共振等方法进行了表征,利用X射线衍射数据确定了其结构。分子式为(C42H70O35)·(C6O2H5N)·7.53(H2O)·0.73(CH3OH),属单斜晶系P21空间群,a=1.51616(4),b=1.02642(4),c=2.09296(3)nm,β=110.209(2)°,V=3.05659(3)nm^3。最小二乘修正结果,R=0.0576。晶体结构测定结果表明,这个超分子体系是属于较少见的“浅包结”方式,客体位于环糊精主体窄口端,伯羟基的O(66),O(67)原子及大多数水分子处于无序状态,大量存在的分子内和分子间氢键,形成了一个密集的氢键网络。氢键是超分子体系形成及稳定存在的主要驱动力。     

Synthesis and Crystal Structure of an Unprecedented Supramolecular Complex [Co(μ2-ClO4)2(H2O)2]•2MA

利用水热法合成了一个结构新颖的超分子化合物[Co(μ2-ClO4)2(H2O)2]·2MA (1),晶体结构表明化合物1是靠氢键和p - p相互作用形成的独特的有机-无机杂化型三维超分子配合物。结构中存在两种不同的超分子构件：a)一维无机链通过氢键形成二维(4,4)拓扑网状构筑单元[Co(μ2-ClO4)2(H2O)2];b)三嗪环之间靠p - p相互作用形成的zigzag链状构筑单元。二者之间通过丰富的氢键和p-p相互作用最终形成了一个三维超分子结构。     

基于香豆素Schiff碱双核Ni（Ⅱ）和立方烷型Cu4（μ3-O）4的四核Cu（Ⅱ）配合物的合成、晶体结构及光谱性质（英文）

合成了2个3-氨基-4-羟基香豆素类Schiff碱双核Ni?髤和立方烷型Cu4(μ3-O)4的四核Cu?髤配合物,[Ni(L1)(DMF)(H2O)]2(1)(H2L1=3-((5-溴-2-羟基-亚苄基)-氨基)-4-羟基-苯并吡喃-2-酮)和[Cu4(L2)4]·DMF·CH3OH·2H2O(2)(H2L2=4-羟基-3-((2-羟基-3-甲氧基-亚苄基)-氨基)-苯并吡喃-2-酮),并通过元素分析、红外光谱、紫外光谱、荧光光谱及X射线单晶衍射分析等手段进行了表征。X射线单晶衍射分析结果表明:配合物1具有双核结构,由2个金属离子和2个配体单元组成,配合物2具有立方烷型Cu4(μ3-O)4的四核结构,由4个金属离子和4个配体单元组成。配合物1是单斜晶系、C2/c空间群;配合物2是四方晶系,I41/a空间群,且中心金属Ni?髤和Cu?髤离子的空间构型均为六配位的扭曲的八面体。此外,配合物1通过分子间氢键、C-H…π及π…π作用形成1D超分子链结构,配合物2通过分子内氢键和π…π作用形成3D超分子结构。此外,研究了H2L1,H2L2及其相应的Ni?髤和Cu?髤配合物的荧光性质。     

3,6-双-O-乙酰膜荚黄芪苷元的晶体和分子结构

3,6-双-O-乙酰膜荚黄芪苷元,C~34H~54O~7,属单斜晶系,空间群P2~1晶胞参数为a=10.902(4),b=17.048(6),c=8.938(3)A,β=107.99(3),V=1580(1)A^3,Z=2,D0=1.21g.cm^-3,D~m=1.18g.cm^-3.结构由直接法解出,对2253个可观察衍射计算,R=0.061,Rw=0.068.结构测定表明,20-C和24-C的构型为R和S,C(16)的羟基上氢原子H(05)与C(25)的羟基上氧原子O(7)形成分子内氢键O(5)-H(05)...(7),同时H(07)与另一个分子的羰基上氧O(2)形成分子间氢键O(7)-H(07)...O(2),通过分子间氢键,晶体中分子形成链状结构.     

L-(-)-α-苯乙胺类立方烷结构2-萘甲酸二聚体盐的晶体结构

L-(-)-α-苯乙胺与消旋的类立方烷结构2-萘甲酸二聚体相互作用形成铵盐,其晶体结构表明,L-(-)-α-苯乙胺与类立方烷结构2-萘甲酸二聚体作用形成的铵离子通过氢键N_2A-HN_2B…O_5A和N_1A-HN_1A…O_3A与类立方烷结构2-萘甲酸二聚体结合在一起.同时类立方烷结构2-萘甲酸二聚体的两个对映异构体之间也存在分子间氢键O_1A-H_1AA…O_6A和O_1B-H_1AB…O_6B.这些氢键将类立方烷结构2-萘甲酸二聚体的两个对映异构体连在同一个晶胞中,呈现两条分子链状堆积.     

一个手性四核铜配合物的合成、结构和CD光谱

香草醛和L-2-氨基-3-苯基-1-丙醇缩合得到的手性希夫碱配体(L-H2vap)与Cu(ClO4)2.6H2O,Gd(NO3)3.6H2O和三乙胺在4-羟基苯甲酸的存在下反应得到L-[Cu4(Hvap)2(vap)2(MeOH)2](ClO4)2.2MeOH.H2O(1)。通过元素分析、红外、热重分析和固体CD光谱对1结构进行了表征,并通过X-射线单晶衍射确定其单晶结构,结果表明1属于单斜晶系,P21手性空间群,Z=2,包含船型{Cu4O4}结构。1的Cu4簇通过配体、溶剂分子和高氯酸根离子的氧原子间的氢键沿b轴形成超分子链。固体CD光谱证实了1的手性。     

三维超分子化合物[H_2(C_4H_(10)N_2)](SO_4)(H_2O)的制备、晶体结构及差热-热重性质研究

用MnSO4H2O和哌嗪在水-甲醇混合溶剂中反应得到了1个超分子化合物[H2(C4H10N2)](SO4)(H2O) (C4H14N2O5S)。 该晶体属单斜晶系, 空间群为P21/n, 晶胞参数为: a = 6.386(1), b = 11.695(2), c = 11.680(2) ? = 101.06(3), V = 856.1(3) 3, Z = 4, Mr =202.23 , Dc = 1.569 g/cm3, F(000) = 432, ?= 0.368 mm-1。 该化合物是由[H2(C4H10N2)]2+、SO42-、H2O通过氢键自组装而形成的。 其中[H2(C4H10N2)]2+存在2种椅式构象:一种[H2(C4H10N2)]2+与4个SO42-、2个H2O通过氢键相连, 另一种[H2(C4H10N2)]2+则与6个SO42-相连。 它们分别沿着b、c方向交替排列展开, 通过SO42-桥联成二维的层状结构;层与层之间在NH…O、CH…O、OH…O氢键的作用下互相连接, 形成了具有网状结构的三维超分子化合物。 差热及热重测试表明:该化合物从92℃开始分解,首先失去1个H2O, 然后再失去[H2(C4H10N2)]2+和SO4 2-。     

以4’-羟基-联苯-4-羧酸和1,3-二(4-吡啶基)丙烷构筑的一维锌配位聚合物的晶体结构与荧光性质

水热条件下采用Zn(NO3)2.6H2O,4′-羟基-联苯-4-羧酸和1,3-二(4-吡啶基)丙烷作为反应物合成出一个新的一维锌金属配位聚合物{[Zn(Hhbc)2(bpp)].H2O}n(1)(Hhbc=4′-羟基-联苯-4-羧酸,bpp=1,3-二(4-吡啶基)丙烷),并分别用元素分析、红外光谱、差热分析、X-射线粉末衍射和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:化合物1为一维链状锌(Ⅱ)配位聚合物,通过分子间的O-H…O氢键作用,一维链进一步被连接成二维超分子结构。荧光分析表明常温固态下配合物1发射蓝色荧光,荧光寿命为3.08 ns(480 nm)。     

新颖的咪唑官能化夹心型钨铋酸盐超分子化合物的合成与晶体结构

在常规条件下合成了一个新颖的超分子化合物Na8H[{Na(H2O)}3{Mn(C3H4N2)}3(BiW9O33)2]·32H2O, 通过X射线单晶结构分析、红外光谱及元素分析对该化合物进行了表征. 结果表明, 该化合物属六方晶系, P6(3)/m空间群. 晶胞参数a=1.394 8(4) nm, b=1.394 8(4) nm, c=3.348 6(19) nm, γ=120°, V = 5.641(4) nm3, Z=12. 该化合物是以α-B-BiW9钨铋酸盐为基本构筑单元的夹心结构化合物. 夹层中心3个Mn2+分别与3个咪唑分子配位形成无机-有机杂化材料. 3个[{Na(H2O)}3{Mn(C3H4N2)}3(BiW9O33)2]9-多阴离子结构基元利用氢键(非典型氢键)沿ab面构筑成具有三角形空穴的二维层状骨架结构. 这种二维层状结构利用氢键作用沿c轴方向交错排列, 形成了含有一维六边形孔道的三维超分子结构.     

基于香豆素Schiff碱双核Ni(Ⅱ)和立方烷型Cu_4(μ_3-O)_4的四核Cu(Ⅱ)配合物的合成、晶体结构及光谱性质（英文）

合成了2个3-氨基-4-羟基香豆素类Schiff碱双核Ni(Ⅱ)和立方烷型Cu_4(μ_3-O)_4的四核Cu(Ⅱ)配合物,[Ni(L~1)(DMF)(H_2O)]_2(1)(H_2L~1=3-((5-溴-2-羟基-亚苄基)-氨基)-4-羟基-苯并吡喃-2-酮)和[Cu_4(L~2)_4]·DMF·CH_3OH·2H_2O (2)(H_2L~2=4-羟基-3-((2-羟基-3-甲氧基-亚苄基)-氨基)-苯并吡喃-2-酮),并通过元素分析、红外光谱、紫外光谱、荧光光谱及X射线单晶衍射分析等手段进行了表征。X射线单晶衍射分析结果表明:配合物1具有双核结构,由2个金属离子和2个配体单元组成,配合物2具有立方烷型Cu_4(μ_3-O)_4的四核结构,由4个金属离子和4个配体单元组成。配合物1是单斜晶系、C2/c空间群;配合物2是四方晶系,I4_1/a空间群,且中心金属Ni(Ⅱ)和Cu(Ⅱ)离子的空间构型均为六配位的扭曲的八面体。此外,配合物1通过分子间氢键、C-H…π及π…π作用形成1D超分子链结构,配合物2通过分子内氢键和π…π作用形成3D超分子结构。此外,研究了H_2L~1,H_2L~2及其相应的Ni(Ⅱ)和Cu(Ⅱ)配合物的荧光性质。     

Four Transition Metal Coordination Polymers based on an Aromatic Multi‐carboxylic Acid as Ligand: Syntheses,Crystal Structures,and Fluorescent/Magnetic Properties

Four compounds, namely, [Zn(H₂L)₂ · 4H₂O] ( 1 ), [Cu(HL) · (H₂O)] · H₂O ( 2 ), [Ni₃L₂(bpy)₂ · 12H₂O] · 4H₂O ( 3 ), and [Co₃L₂(bpy)₂ · 12H₂O] · 4H₂O ( 4 ) [H₃L = 4, 4′‐[(5‐carboxy‐1, 3‐phenylene)bis(oxy)]dibenzoic acid], were synthesized under solvothermal conditions by employing a semi‐rigid aromatic multi‐carboxylic acid ligand (H₃L) and ancillary nitrogen ligand (bpy = 4, 4′‐bipyridine). X‐ray diffraction studies revealed that complexes 1 , 3 , and 4 show zero‐dimensional (0D) structures, which were further extended to distinct 3D supramolecular nets by extensive hydrogen‐bond interactions. However, in compound 2 , 1D chains of square‐shaped pores were linked together by HL^2– ligands to generate a 2D porous layer along the ac plane. Comparison of the structures indicated that not only the conformation of the functional ligand, but also the ancillary ligand helped in structural determination of the compounds. Compound 1 exhibited solid fluorescence emission originating from an intraligand π→π* transition. Magnetic susceptibility measurements demonstrated that compound 2 exhibited antiferromagnetic coupling between adjacent copper(II) ions, with the corresponding J values of –141.84 cm^–1. Furthermore, the thermal behaviors of the complexes 1 – 4 were studied by thermogravimetric analysis.     

Hydrogen‐bonding interactions in the 4‐aminobenzoic acid salt of atenolol monohydrate

Atenolol {or 4‐[2‐hydroxy‐3‐(isopropylamino)propoxy]phenylacetamide} crystallizes with 4‐aminobenzoic acid to give the salt {3‐[4‐(aminocarbonylmethyl)phenoxy]‐2‐hydroxypropyl}isopropylammonium 4‐aminobenzoate monohydrate, C₁₄H₂₃N₂O₃⁺·C₇H₆NO₂⁻·H₂O. In the crystal structure, the water molecule, the carboxylate group of 4‐aminobenzoate, and the hydroxy and ether O atoms of atenolol form a supramolecular R₃³(11) heterosynthon. Three other types of supramolecular synthons link the asymmetric unit into a two‐dimensional structure.     

Supramolecular Architectures with Open Frameworks Constructed by Transitional Metal Ions,Linear Dicarboxylic Acid,and 2,2′‐Bipyridine

Four new transitional metal supramolecular architectures, [Zn(cca)(2,2′‐bpy)]_n · n(2,2′‐bpy) ( 1 ), [Cu(cca)(2,2′‐bpy)]_n ( 2 ), [Zn(bpdc)(2,2′‐bpy)(H₂O)]_n · 0.5nDMF · 1.5nH₂O ( 3 ), and [Co(bpdc)(2,2′‐bpy)(H₂O)]_n · nH₂O ( 4 ) (H₂cca = p‐carboxycinnamic acid; H₂bpdc = 4,4′‐biphenyldicarboxylic acid; 2,2′‐bpy = 2,2′‐bipyridine) were synthesized by hydrothermal reactions and characterized by single crystal X‐ray diffraction, elemental analyses, and IR spectroscopy. Although the metal ions in these four compounds are bridged by linear dicarboxylic acid into 1D infinite chains, there are different π–π stacking interactions between the chains, which results in the formation of different 3D supramolecular networks. Compound 1 is of a 3D open‐framework with free 2,2′‐bpy molecules in the channels, whereas compound 2 is of a complicated 3D supramolecular network. Compounds 3 and 4 are isostructural. Both compounds have open‐frameworks.     

Synthesis and characterization of a cadmium(II)–organic supramolecular coordination compound based on the multifunctional 2‐amino‐5‐sulfobenzoic acid ligand

Much attention has been paid by chemists to the construction of supramolecular coordination compounds based on the multifunctional ligand 5‐sulfosalicylic acid (H₃SSA) due to the structural and biological interest of these compounds. However, no coordination compounds have been reported for the multifunctional amino‐substituted sulfobenzoate ligand 2‐amino‐5‐sulfobenzoic acid (H₂asba). We expected that H₂asba could be a suitable building block for the assembly of supramolecular networks due to its interesting structural characteristics. The reaction of cadmium(II) nitrate with H₂asba in the presence of the auxiliary flexible dipyridylamide ligand N,N′‐bis[(pyridin‐4‐yl)methyl]oxamide (4bpme) under ambient conditions formed a new mixed‐ligand coordination compound, namely bis(3‐amino‐4‐carboxybenzenesulfonato‐κO¹)diaquabis{N,N′‐bis[(pyridin‐4‐yl)methyl]oxamide‐κN}cadmium(II)–N,N′‐bis[(pyridin‐4‐yl)methyl]oxamide–water (1/1/4), [Cd(C₇H₆NO₅S)₂(C₁₄H₁₄N₄O₂)₂(H₂O)₂]·C₁₄H₁₄N₄O₂·4H₂O, (1), which was characterized by single‐crystal and powder X‐ray diffraction analysis (PXRD), FT–IR spectroscopy, thermogravimetric analysis (TG), and UV–Vis and photoluminescence spectroscopic analyses in the solid state. The central Cd^II atom in (1) occupies a special position on a centre of inversion and exhibits a slightly distorted octahedral geometry, being coordinated by two N atoms from two monodentate 4bpme ligands, four O atoms from two monodentate 4‐amino‐3‐carboxybenzenesulfonate (Hasba⁻) ligands and two coordinated water molecules. Interestingly, complex (1) further extends into a threefold polycatenated 0D→2D (0D is zero‐dimensional and 2D is two‐dimensional) interpenetrated supramolecular two‐dimensional (4,4) layer through intermolecular hydrogen bonding. The interlayer hydrogen bonding further links adjacent threefold polycatenated two‐dimensional layers into a three‐dimensional network. The optical properties of complex (1) indicate that it may be used as a potential indirect band gap semiconductor material. Complex (1) exhibits an irreversible dehydration–rehydration behaviour. The fluorescence properties have also been investigated in the solid state at room temperature.     

Syntheses,Structures, and Electrochemical Properties of Two Bis‐triazole‐bis‐amide‐based Copper(II) Pyridine‐2,3‐dicarboxylate Coordination Polymers

Abstract. Two bis‐triazole‐bis‐amide‐based copper(II) pyridine‐2,3‐dicarboxylate coordination polymers (CPs), [Cu(2,3‐pydc)(dtb)_0.5(DMF)] · 2H₂O ( 1 ) and [Cu(2,3‐pydc)(dth)_0.5(DMF)] · 2H₂O ( 2 ) (2,3‐H₂pydc = pyridine‐2,3‐dicarboxylic acid, dtb = N,N′‐bis(4H‐1,2,4‐triazole)butanamide, and dth = N,N′‐bis(4H‐1,2,4‐triazole)hexanamide), were synthesized under solvothermal conditions. CPs 1 and 2 show similar two‐dimensional (2D) structures. In 1 , the 2,3‐pydc anions bridge the Cu^II ions into a one‐dimensional (1D) chain. Such 1D chains are linked by the dtb ligands to form a 2D layer. The adjacent 2D layers are extended into a three‐dimensional (3D) supramolecular architecture by hydrogen‐bonding interactions. The electrochemical properties of 1 and 2 were investigated.     

Supramolecular architectures of succinates of 1‐hydroxypropan‐2‐aminium derivatives

Aminoalkanol and aroxyalkyl derivatives are known as potential anticonvulsants. Two new salts, namely bis{(R,S)‐N‐[2‐(2,6‐dimethylphenoxy)ethyl]‐1‐hydroxypropan‐2‐aminium} succinate ( 1s ), C₁₃H₂₂NO₂⁺·0.5C₄H₄O₄²⁻, and bis{(S)‐(+)‐N‐[2‐(2,6‐dimethylphenoxy)ethyl]‐1‐hydroxypropan‐2‐aminium} succinate ( 2s ), C₁₃H₂₂NO₂⁺·0.5C₄H₄O₄²⁻, have been prepared and characterized by single‐crystal X‐ray diffraction. The N atoms are protonated by proton transfer from succinic acid. Salt 1s crystallizes in the space group P2₁/n with one cation and half an anion in the asymmetric unit across an inversion centre, while ( 2s ) crystallizes in the space group P2₁ with four cations and two anions in the asymmetric unit. The hydroxy group of the cation of 1s is observed in two R/S disorder positions. The crystals of these two salts display similar supramolecular architectures (i.e. two‐dimensional networks), built mainly by intermolecular N⁺—H…O^δ− and O—H…O^δ− hydrogen bonds, where `δ−' represents a partial charge. The succinate anions are engaged in hydrogen bonds, not only with protonated N atoms, but also with hydroxy groups.     

1:2 Complexes of chloranilic acid with pyrazole and imidazole,and the aceto­nitrile solvate of a 1:1 complex with imidazole

2,5‐Di­chloro‐3,6‐di­hydroxy‐1,4‐benzo­quinone (chloranilic acid) forms X—H?Y (X, Y = N or O) and C—H?Cl hydrogen bonds with pyrazole and imidazole to afford bis­(pyrazolium) di­chloro­anilate and bis­(imidazolium) di­chloro­anilate, (I) and (II), both 2C₃H₅N₂⁺·C₆Cl₂O₄^2?, and imidazolium chloro­anilate aceto­nitrile solvate, C₃H₅N₂⁺·­C₆HCl₂O₄^?·C₂H₃N, (III). Their crystal structures demonstrate three novel supramolecular architectures based on supramolecular synthons to build a ladder, (I), a two‐dimensional network, (II), and a flat ribbon, (III).     

Syntheses, Supramolecular Structures and Antibacterial Activities of Five Helical Transition Complexes with 5-Chloro-1-phenyl-1H-pyrazole-3,4-dicarboxylic Acid

Five new transition metal complexes [Cu(HL)₂(H₂O)₂] ( 1 ), [Cu(HL)₂(phen)] ( 2 ), [Cu(HL)₂(H₂O)]₂(4,4′‐bipy) ( 3 ), [Zn(HL)₂(H₂O)₂]·(4,4′‐bipy) ( 4 ), [Ag(HL)(4,4′‐bipy)]_n ( 5 ), (H₂L=5‐chloro‐1‐phenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid, phen=1,10‐phenanthroline; 4,4′‐bipy=4,4′‐bipyridine) have been synthesized and characterized. Complexes 1 , 2 and 4 exhibit monomeric structures, 3 shows a dinuclear structure, 5 displays 1D chain structure, and all extend to 3D supramolecular network via rich hydrogen bonds. Complexes 1 , 2 , 3 , 5 comprise single helical chains, while complex 4 generates quadruple‐stranded helical chains. Furthermore, the antibacterial activities of the titled complexes against bacterial species, three Gram positive bacteria (Staphylococcus aureus, Bacillus subtilis and Candida albicans) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were studied and compared to the activities of free ligands by using the microdilution method.     

Hydrogen‐bonded assemblies in the molecular crystals of 2,2′‐thiodiacetic acid with ethylenediamine and o‐phenylenediamine

Carboxylate molecular crystals have been of interest due to the presence of hydrogen bonding, which plays a significant role in chemical and crystal engineering, as well as in supramolecular chemistry. Acid–base adducts possess hydrogen bonds which increase the thermal and mechanical stability of the crystal. 2,2′‐Thiodiacetic acid (Tda) is a versatile ligand that has been widely explored, employing its multidendate and chelating coordination abilities with many metals; however, charge‐transfer complexes of thiodiacetic acid have not been reported. Two salts, namely ethylenediaminium 2,2′‐thiodiacetate, C₂H₁₀N₂²⁺·C₄H₄O₄S₂²⁻, denoted Tdaen, and 2‐aminoanilinium 2‐(carboxymethylsulfanyl)acetate, C₆H₉N₂⁺·C₄H₅O₄S⁻, denoted Tdaophen, were synthesized and characterized by IR, ¹H and ¹³C NMR spectroscopies, and single‐crystal X‐ray diffraction. In these salts, Tda reacts with the aliphatic (ethylenediamine) and aromatic (o‐phenylenediamine) diamines, and deprotonates them to form anions with different valencies and different supramolecular networks. In Tdaen, the divalent Tda²⁻ anions form one‐dimensional linear supramolecular chains and these are extended into a three‐dimensional sandwich‐type supramolecular network by interaction with the ethylenediaminium cations. However, in Tdaophen, the monovalent Tda⁻ anions form one‐dimensional zigzag supramolecular chains, which are extended into a three‐dimensional supramolecular network by interaction with the 2‐aminoanilinium cations. Thus, both three‐dimensional structures display different ring motifs. The structures of these diamines, which are influenced by hydrogen‐bonded assemblies in the molecular crystals, are discussed in detail.     

Supramolecular Hydrogen‐Bonded Frameworks from a New Bisphosphonic Acid and Transition Metal Ions

The reaction of 2‐morpholinoethylimino‐bis(methylenephosphonic acid) (H₄L) with cobalt(II), nickel(II) acetate, and cadmium(II) chloride in ethanol/water mixed solvents afforded three new crystal‐engineered supramolecular metal phosphonates, Co(H₃L)₂ · 2H₂O ( 1 ), Ni(H₃L)₂ · 2H₂O ( 2 ), and [Cd₂Cl₄(H₂O)₆]_0.5[H₄L] ( 3 ) by using a layering technique. The cobalt(II) ions in complex 1 are hexacoordinated by four phosphonate oxygen atoms and two imino nitrogen atoms. The mononuclear units of complex 1 are connected through hydrogen bonds to form a three dimensional supramolecular network. The structure of compound 2 is analogous to that of 1 except that the cobalt(II) ion in compound 1 is replaced by nickel(II) in compound 2 . In the molecular structure of compound 3 , cadmium is coordinated to three chloride ions and three aqua oxygen atoms to form a novel neutral dinuclear complex. Several hydrogen bonds connect the dinuclear complex and the neutral form of the ligand to build a supramolecular three dimensional structure.