Synthesis and Crystal Structure of Macrocyclic Cavitand Cucurbit[5]uril and Its Supramolecular Adduct with Cu（Ⅱ）

The first supramolecular adduct (H₃O)₂[Cu(H₂O)₄](SO₄)₂·2(C₃₀H₃₀N₂₀O₁₀)·₂₄(H₂O) based on cucurbit[5]uril was synthesized and characterized by single crystal X‐ray diffraction analysis. In the adduct, copper ion is coordinated by four oxygen atoms from H₂O. The latter links two cucurbit[5]uril molecules due to a complicated hydrogen bonding containing lattice water molecules.     

(英)两个基于大环配体五员瓜环的异核金属配合物的合成及晶体结构

设计并合成了两个五员瓜环(Q[5])桥联K+和Na+形成的新型配合物[K(H2O)2Na(H2O)Q[5]](ClO4)2·6H2O(1),[KNaH(H2O)4Q[5]]n(ClO4)3n·3nH2O(2)。利用单晶X射线衍射进行结构测定,结果表明,配合物1中Q[5]起着一个双五齿配体的作用,每个端口的5个羰基氧原子分别和钾离子和钠离子配位,形成分子胶囊;配合物2中每个钾离子分别通过与相邻的2个Q[5]端口的相邻一对羰基氧原子配位,使得配合物形成一维链状结构,同时Q[5]还提供1个羰基氧原子与Na+配位,氢键使得配合物形成三维超分子结构。     

Chlorine anion encapsulation by molecular capsules based on cucurbit[5]uril and decamethylcucurbit[5]uril

Three barrel-shaped artificial molecular capsules 1-3, based on normal cucurbit[5]uril (Q[5]) and decamethylcucurbit[5]uril (Me10Q[5]), were synthesized and structurally characterized by single-crystal X-ray diffraction. Encapsulation of a chlorine anion in the cavity of a Q[5] or Me10Q[5] to form closed a molecular capsule with the coordinated metal ions or coordinated metal ions and water molecules in the crystal structures of these compounds is common. The three complexes [Pr2(C30H30N20O10)Cl3(H2O)13]3+ 3 Cl- x 5 H2O (1), [Sr2(C40H50N20O10)(H2O)4Cl]3+ 3 Cl- x 2 (HCl) 19 H2O (2) and [K(C40H50N20O10)(H2O)Cl] x [Zn(H2O)2Cl2] x [ZnCl4]2- x 2 (H3O)+ x 8 H2O (3) all crystallize as isolated molecular capsules.     

Inclusion of Two PhP(O)(OH) 2 Guest Molecules into the Cavity of Macrocyclic Cavidand Cucurbit[8]uril

A new inclusion compound which is a supramolecular adduct of cucurbit[8]uril with two guest molecules of phenylphosphonic acid, PhP(O)(OH)₂, included into the cavity as ``two guests in host'' is reported. The guests match both size and hydrophilicity/hydrophobicity requirements. Two phenyl groups of molecules of PhP(O)(OH)₂ are directed toward the center of the large hydrophobic cavity whereas the PO(OH)₂ groups are outward-looking and bound with each hydrophilic portal of cucurbit[8]uril by a short hydrogen bond.     

Synthesis and crystal structure of a supramolecular adduct of trinuclear molybdenum oxocluster with macrocyclic cavitand cucurbit[5]uril containing the included ionic associate Na<Superscript>+</Superscript>...Cl...Na<Superscript>+</Superscript>

The compound of composition [{Mo₃O₄(H₂O)₆Cl₃}₂(Na₂Cl⊂ C₃₀H₃₀N ₂₀O₁₀)]Cl₃⋅14H₂O (1) was prepared by evaporation of a hydrochloric acid solution containing NaCl, the trinuclear aqua complex [Mo₃O₄(H₂O)₉]⁴⁺, and the macrocyclic cavitand cucurbit[5]uril (C₃₀H₃₀N₂₀O₁₀). X-ray diffraction analysis demonstrated that the cucurbit[5]uril molecule is closed on both sides by the cluster cations through hydrogen bonding between the CO groups of the cucurbit[5]uril portals and the aqua ligands of the oxo cluster. The inner cavity of the supramolecular adduct includes an unusual ionic associate Na⁺...Cl...Na⁺. The sodium cations are coordinated by five carbonyl oxygen atoms of each portal of the macrocycle. Compound 1 is the first structurally characterized complex, in which the macrocyclic cucurbit[5]uril ligand is directly coordinated to the alkali metal cation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1513–1517, July, 2005.     

Improvement of Dispersion and Release Properties of Nifedipine in Suppositories by Complexation with 2-Hydroxypropyl-β-cyclodextrin

Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril, and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex building ability.     

Aqueous solution chemistry of [Mo3CuSe4]n+ (n = 4, 5) and [W3CuQ4]5+ (Q = S, Se) clusters

The triangular cluster [Mo3Se4(H2O)9]4+ reacts with Cu turnings to give a new heterometallic cuboidal cluster [Mo3CuSe4(H2O)10]4+(purple; UV/Vis lambda(epsilon): 352(3907), 509(2613)). The reaction of [Mo3Se4(H2O)9]4+ with CuCl afforded the 5+ cube [Mo3CuSe4(H2O)10]5+(red; UV/Vis lambda(epsilon): 356(5406), 500(3477)). In contrast, [W3Se4(H2O)9]4+ both with Cu and CuCl gives the 5+ cube, [W3CuSe4(H2O)10]5+(yellow-green; UV/Vis lambda(epsilon): 312(5327), 419(3256) and 628(680)). Cyclic voltammetry of [M3CuQ4(H2O)10]5+ in 2 M HCl (M = Mo, W; Q = S, Se) shows a reversible one-electron reduction wave for the Mo clusters, but no reduction occurs for the W clusters prior to H+ reduction. In HCl solutions, Cl is coordinated to the Cu site of the clusters, alongside some less extensive coordination to Mo and W, and for [W3(CuCl)S4(H2O)6Cl3]+, isolated as the supramolecular adduct with cucurbit[6]uril, [W3(CuCl)S4(H2O)6Cl3]2Cl2 x C36H36N24O12 x 12H2O, the crystal structure was determined (Cu-W 2.856(4) angstroms, W-W 2.7432(15) angstroms, Cu-Cl 2.167(13) angstroms).     

Synthesis and guest exchange reactions of inclusion compounds of cucurbit[8]uril with nickel(II) and copper(II) complexes

Inclusion compounds of the macrocyclic cavitand cucurbit[8]uril (CB[8]) with the nickel(II) complex, {trans-[Ni(en)₂(H₂O)₂]@CB[8]}Cl₂ · 23.5H₂O, the copper(II) complex, {2[Cu(dien)(bipy)(H₂O)]@CB[8]}(ClO₄)₄ · 11H₂O, and the organic molecules, 2(pyCN)@CB[8]} · 16H₂O and {2(bpe)@CB[8]} · 17H₂O, where bipy is 4,4′-bipyridyl, pyCN is 4-cyanopyridine, and bpe is trans-1,2-bis(4-pyridyl)ethylene, were synthesized. The inclusion compounds with organic molecules were synthesized starting from inclusion compounds of cucurbit[8]uril with cyclam and ethylenediamine complexes of copper(II) and nickel(II) by the guest exchange method, which is based on the replacement of one guest with another in the cavity of the cavitand The resulting compounds were characterized by X-ray diffraction, ESR, ¹H NMR, IR, and electronic absorption spectroscopy, and electrospray mass spectrometry. Photochemically induced [2+2]-cycloaddition of two 1,2-bis(4-pyridyl)ethylene molecules included in cucurbit[8]uril was studied. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 25–34, January, 2006.     

六元瓜环与磺基水杨酸主客体配合物的晶体结构

合成了六元瓜环与磺基水杨酸主客体配合物,并测定了其单晶结构.晶体结构表明六元瓜环包结了3个水分子,磺基水杨酸位于六元瓜环的外侧,且与水分子通过氢键与六元瓜环相连,瓜环之间通过端口的羰基O原子、磺基水杨酸以及水分子间的氢键作用形成一维超分子.     

瓜环与哌嗪衍生物主客体配合物的研究(英)

本文采用核磁共振技术研究瓜环与哌嗪衍生物主客体配合物的结构特征。¹H核磁共振谱证实八元瓜环能与一些哌嗪衍生物形成稳定的双客体主客体配合物,六元瓜环与一些哌嗪衍生物形成稳定的1∶1主客体配合物。而五、七元瓜环和哌嗪衍生物则未表现出明显地相互作用。形成的自组装主客体配合物得到质谱的进一步证实。     

Synthesis and crystal structure of a supramolecular adduct of the aqua nitrato complex of gadolinium [Gd(NO<Subscript>3</Subscript>)(H<Subscript>2</Subscript>O)<Subscript>7</Subscript>]<Superscript>2+</Superscript> with macrocyclic cavitand cucurbit[6]uril

A supramolecular adduct of gadolinium aqua nitrato complex and cucurbit[6]uril { [Gd(NO₃)(H₂O)₇](C₅H₅N)@(C₃₆H₃₆N₂₄O₁₂)}(NO₃)₂·10H₂O is obtained by slow diffusion of methanol into an aqueous solution containing gadolinium nitrate, pyridine, and cucurbit[6]uril. According to single crystal X-ray diffraction data, water molecules coordinated to metal atom make hydrogen bonds to polarized carbonyl groups of the macrocycle. The heptaaquanitratogadolinium(III) [Gd(NO₃)(H₂O)₇]²⁺ cation is structurally characterized for the first time. Crystal system is triclinic, space group \(P\overline 1 \), a = 12.3137(4) Å, b = 14.2334(5) Å, c = 19.5629(6) Å; α = 80.850(1)°, β = 86.879(1)°, γ = 68.855(1)°; V = 3157.15(18) ų, Z = 2. Oriented hydrogen-bonded chains of alternating cucurbit[6]uril molecules and gadolinium aqua cations form in the crystal structure.     

Fluorescent uranyl ion lidded cucurbit[5]uril capsule

A novel fluorescent complex {(UO(2))(2)(CB5)}(NO(3))(4)·4HNO(3).3H(2)O (U2CB5) is obtained from cucurbit[5]uril (CB5) and uranyl nitrate under ambient temperature conditions. The crystal structure revealed that two uranyl ions are coordinated to the two open portals of CB5 giving a closed molecular capsule, which further connected through CB5 molecules to give two-dimensional frameworks. The U2CB5 complex was further investigated by NMR, FTIR and TGA techniques. The Fluorescence of uranyl ion was found to be enhanced due to complexation with cucurbituril.     

Recognition of glycine by cucurbit[5]uril and cucurbit[6]uril: A comparative study of exo- and endo-binding

Recognition features of glycine (Gly) with cucurbit[5]uril (Q[5]) and cucurbit[6]uril (Q[6]) both in aqueous solution and solid state were investigated by ¹H NMR spectroscopy and X-ray crystallography. ¹H NMR data indicate that the Gly is located outside of the portals of the Q[5], exhibiting exo binding with the Q[5]. In the case of the Q[6], the Gly shows endo binding or a dual binding mode (endo and exo binding) with the host, which depends on the amount of the host in the aqueous solution. X-ray crystallography clearly display that the Gly forms 2:1 exclusion complex with the Q[5], and 2:1 inclusion complex with the Q[6]. Interestingly, hydrogen bondings between the encapsulated Gly molecules in the Q[6] were observed.     

Cucurbit[5]uril derivatives as oxygen carriers

ABSTRACT

Cucurbit[n]urils are rigid cage-molecules of pumpkin-like shape, made of n-glycoluril units, able to bind mainly neutral molecules and cations. In this work, we investigate the binding of three cucurbit[5]uril derivatives with dioxygen O₂ and show that one of them, namely per-hydroxylated cucurbit[5]uril, (OH)₁₀CB[5], is able to significantly bind dioxygen gas at physiological temperature, even in the presence of sodium chloride at the concentration of injectable solution in blood. As cucurbit[n]urils studied up to now reveal low toxicity, per-hydroxylated cucurbit[5]uril appears as a promising precursor to design a host able to transport O₂ in a haemoglobin substitute solution.     

七、八元瓜环与二溴化1,n-亚烷基-二-2-甲基吡啶的超分子自组装

合成和表征了4个碳链长度不同二溴化1,n-亚烷基-二-2-甲基吡啶(客体,n=6,8,10,12),利用1H NMR技术、热重分析及紫外吸收光谱法考察了这些客体与七、八元瓜环(主体)的相互作用,以及形成的主客体包结物的结构特征.研究结果表明4个客体与七、八元瓜环形成不同的主客体包合物.七元瓜环可穿梭在线性客体分子上形成类轮烷型或哑铃型主客体包合物;而由于具有较大的空腔,八元瓜环可包容弯曲状的整个客体分子.     

Investigation of Host–Guest Compounds of Cucurbit[n=5–8]uril with Some Ortho Aminopyridines and Bispyridine

Host–guest complexes of cucurbit[n=5–8]uril and some examples of ortho substituted pyridines or aminopyridines were examined by ¹H NMR spectroscopy. Portal binding of two ortho aminopyridine free bases, by cucurbit[5]uril, was observed in ¹H NMR spectra. Combined cavity and portal binding in cucurbit[6]uril were observed for both the free base 2-aminomethylpyridine, ampy, the HCl salt, ampy·1HCl, and the salt of 2,2′-bispyridine, bpy·1HCl. Two novel complexes were formed with cucurbit[6]uril. The free base ampyas a dual occupant, formed a 2:1 complex, and bpy·1HCl formed a stable asymmetric 1:1 complex. Only portal binding of 2,6-bisaminomethylpyridine and its salts was observed for cucurbit[6]uril. Fast exchange of the free base and pyridineammonium salts was observed for cucurbit[7-8]uril.This revised version was published online in July 2005 with a corrected issue number.     

Cucurbit[5]uril, Decamethylcucurbit[5]uril and Cucurbit[6]uril. Synthesis, Solubility and Amine Complex Formation

A simple way to prepare cucurbit[5]uril is described. The macrocycles of the cucurbituril type are nearly insoluble in water. The solubilities of cucurbit[5]uril, decamethylcucurbit[5]uril and cucurbit[6]uril in hydrochloric acid, formic acid and acetic acid of different concentrations have been investigated. Due to the formation of complexes between cucurbit[n]urils and protons the solubility increases in aqueous acids. The macrocyclic ligands are able to form complexes with several organic compounds. Thus, the complex formation of the cucurbituril macrocycles with different amines has beenstudied by means of calorimetric titrations. The reaction enthalpy gives noevidence of the formation of inclusion or exclusion complexes. ¹H-NMR measurements show that in the case of cucurbit[5]uril and cucurbit[6]uril the organic guest compound is included within the hydrophobic cavity. Decamethylcucurbit[5]uril forms only exclusion complexes with organicamines. This was confirmed by the crystal structure of the decamethylcucurbit[5]uril-1,6-diaminohexane complex.     

新型葫六环联脲桥联双核钆(Ⅲ)配合物的合成、晶体结构及其热稳定性

设计并合成了一个新型的葫六环联脲(Q6)桥联的双核钆新型配合物———{[Gd(H2O)6]2[Q6(H2O)]}Cl6.4H2O(1),其结构经单晶X-射线衍射,IR和元素分析表征。1属单斜晶系,P21/c空间群,晶胞参数a=12.179(2),b=19.704(4),c=14.579(3),β=112.79(3)°,V=3 225.5(11)3,Z=2,Mr=1 830.36,Dc=1.885 Mg.m-3,F(000)=1 832,μ=2.39 mm-1,GOF=1.079,R1=0.036,wR2=0.098。在1的分子结构中,Q6起着一个双-双齿配体的作用,每个Gd(Ⅲ)和Q6的两个相邻的羰基氧原子及来自六个水分子的六个氧原子配位,Q6的空腔内有一个无序的客体水分子,氢键使1形成三维超分子结构。热分析研究表明,1的热稳定性较好。     

L-Cysteine as a chiral linker in lanthanide-cucurbit[6]uril one-dimensional assemblies

The reaction of neodymium, europium, or terbium nitrate with cucurbit[6]uril (CB6) in the presence of the α-amino acid L-cysteine (L-cys) gives the complexes [Nd(L-cys)(CB6)(NO(3))(H(2)O)(4)]·2NO(3)·10H(2)O (1) and {[Ln(L-cys)(CB6)(H(2)O)(5)][Ln(L-cys)(CB6)(NO(3))(H(2)O)(4)]}·5NO(3)·22H(2)O with Ln = Eu (2) or Tb (3). 2 and 3 only differ from 1 by the presence of two independent metal ions in slightly different environments. In all cases, each metal atom is bound to the bidentate CB6 and the monodentate L-cys molecules, with the latter being in its zwitterionic form. The ammonium group of L-cys is directed away from CB6 and is involved in ion-dipole and hydrogen bonding interactions with the uncomplexed portal of the neighboring molecule, which gives rise to the formation of chiral one-dimensional assemblies of columnar shape.     

Synthesis, structure and reactivity of cuboidal-type cluster aqua complexes with W3PdS4 4+ core

The reaction of PdCl(2) with [W3S4(H2O)9]4+ in the presence of hypophosphorous acid in 2 M HCl gives cuboidal cluster [W3(PdCl)S4(H2O)9]3+ (1) which undergoes condensation and crystallises from Hpts solutions as edge-linked double cubane cluster [{W3PdS4(H2O)9}2](pts)(8).19H2O (pts = p-toluenesulfonate) (1'). The substitution of Cl- in (1) by different ligands was explored. The Pd atom in the cluster shows an exceptionally high reactivity in the isomerisation of the hydrophosphoryl H2P(O)(OH), HP(O)(OH)2, HPPh(O)(OH) and HPPh2(O) molecules into the corresponding hydroxo tautomers HP(OH)2, P(OH)3, PhP(OH)2 and Ph2P(OH) stabilised by coordination at Pd. The reactions were followed by UV-Vis spectrophotometry and 31P NMR. Formation constants of the 1 : 1 coordination of [M3(PdCl)S4(H2O)9]3+ (M = Mo, W) with HP(OH)2 and As(OH)3 were obtained. The structures of cucurbit[6]uril (C36H36N24O12, CUC[6]) adducts [W3(PdP(OH)3)S4(H2O)8Cl]-(C36H36N24O12)Cl3.12.5H2O (2), and [W3Pd(PhP(OH)2)S4(H2O)7Cl2]2(C36H36N24O12)Cl4.9H2O (3) were determined by single-crystal X-ray diffraction.