A charge-transfer complex of 10,10'-dihydroxy-9,9'-biphenanthryl and methylviologen as a visual inclusion host system

A charge-transfer (CT) complex, composed of 10,10'-dihydroxy-9,9'-biphenanthryl as the electron donor and 1,1'-dimethyl-4,4'-bipyridinium dichloride as the electron acceptor, is formed only by the inclusion of guest molecules. The color of this inclusion CT complex is sensitive to the component guest molecules.     

Electrochemical control of surface properties using a quinone-functionalized monolayer: effects of donor-acceptor complexes

A benzoquinone monolayer-functionalized electrode reveals electrochemically or chemically controlled wettability; the hydrophobicity of the hydroquinone-modified surface is enhanced by the presence of a donor-acceptor complex with N,N'-dimethyl-4,4'-bipyridinium as the pi-electron acceptor.     

Interaction of DNA and a series of aromatic donor-viologen acceptor molecules with and without the presence of CB[8

A series of 1-ethyl-1'-arylmethyl-4,4'-bipyridinium compounds is synthesized, where the aryl is phenyl (BEV), 2-naphthyl (NEV), 2-anthracenyl (AEV) or 1-pyrenyl (PEV). Among them, PEV and AEV can bind with calf thymus DNA mainly through intercalation and groove-binding modes, and both of them can be observed to photocleave plasmid pBR 322 DNA significantly under irradiation with a xenon arc lamp. After inclusion of cucurbit[8]uril (CB[8]), all of the aromatic donor-viologen acceptor compounds exhibit efficient DNA photocleavage ability. The reason is that CB[8] can inhibit the intramolecular backwards electron transfer in the aromatic donor-viologen acceptor molecule, prolonging the lifetime of the charge separated excited state to some extent. These studies bring a new subject in DNA photocleavage research and a potential application of the host-guest supramolecular system.     

Iodobismuthates with N-alkyl- or N,N'-dialkyl-4,4'-bipyridinium: syntheses, structures and dielectric properties

The solvothermal reactions of BiI(3), KI, I(2), 4,4'-bipyridine (4,4'-bipy), and a small amount of water in alcohol and acetonitrile produced four bipyridinium iodobismuthates {[MQ](3)[Bi(2)I(6)(μ-I)(3)][Bi(2)I(6)(μ-I)(2)(MQ)(2)](3)} (1, MQ(+) = N-methyl-4,4'-bipyridinium), {[EQ](3)[Bi(2)I(6)(μ-I)(3)][Bi(2)I(6)(μ-I)(2)(EQ)(2)](3)} (2, EQ(+) = N-ethyl-4,4'-bipyridinium), [MV][BiI(5)] (Eur. J. Inorg. Chem., 2010, 5326) (3, MV(2+) = N,N'-dimethyl-4,4'-bipyridinium), and [EV](2)[Bi(4)I(10)(μ-I)(4)(μ(3)-I)(2)] (4, EV(2+) = N,N'-diethyl-4,4'-bipyridinium). In these reactions, 4,4'-bipy was partly or completely alkylated by alkyl groups generated from the cleavage of C-O bond of alcohols, forming the N-alkyl-4,4'-bipyridinium cation (Q(+)) and the N,N'-dialkyl-4,4'-bipyridinium dication (V(2+)), respectively. Compounds 1-4 were characterized by elemental analysis, IR, (1)H NMR and single-crystal X-ray diffraction analysis. The optical, electrical conductive and dielectric properties of these compounds were investigated. The dielectric constants of the Q(+)-based compounds were larger than the values of the V(2+)-based ones, which showed that the weak electrostatic interactions in the structures may benefit the polarizability of molecules, thereby resulting in a larger dielectric response of the structures under an external electric field, while the strong electrostatic interactions between the positive and negative charge units would lead to a low dielectric constant (low-k) behavior of these compounds.     

Supramolecular Terbium-SIP Complex Pillared by 4,4'-Bipyridyl,{[Tb(SIP)(H_2O)_5]_2(bpy)_3(H_2O)}n:Synthesis,Crystal Structure and Photoluminescence

The supramolecular terbium complex, {[Tb(SIP)(H2O)5]2(bpy)3(H2O)}n (NaH2SIP= 5-sulfoisophthalic acid monosodium salt and bpy=4,4'-bipyridyl), has been synthesized by the hydrothermal reaction of Tb4O7 with NaH2SIP and bpy at 165 ℃, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectrum, powder X-ray diffraction and photoluminescence spectrum. It crystallizes in a monoclinic system, space group C2/c, with a= 30.6840(1), b=10.9206(2), c=17.4967(3), β=111.931(1)o, V=5438.65(14)3, Z=4, C46H52N6O25S2Tb2, Mr=1470.90, Dc=1.796 g/cm3, μ=2.747 mm-1, F(000)=2928, the final R= 0.0654 and wR=0.1322 for 3806 observed reflections with I > 2σ(I). In the neutral [Tb(SIP)(H2O)5]2 motif, the Tb(III) ions are linked by the SIP ligands to form a one-dimensional zigzag chain propagating along the c axis. The zigzag chains are linked together by hydrogen bonds and π-π stacking interactions to form a two-dimensional supramolecular framework. The uncoordinated bpy molecules act as pillars to extend the two-dimensional sheets into a distinctive pillared three-dimensional supramolecular structure through O-H···N hydrogen bonds. The photoluminescence of the complex was investigated at room temperature in the solid state.     

对称四甲基六元瓜环与1-丁基-4,4’-联吡啶的超分子自组装

设计合成了客体分子1-丁基-4,4’-联吡啶溴化物(BV+),利用核磁共振、紫外-可见吸收光谱、热重分析及X射线单晶衍射研究其与对称四甲基六元瓜环(TMeQ[6])的超分子自组装及形成的主客体包结配合物的结构特征.结果表明,在溶液中及固体状态下,TMeQ[6]均包结BV+的烷基链部分形成1∶1包结配合物.     

A photochemically driven molecular-level abacus

A molecular-level abacus-like system driven by light inputs has been designed in the form of a [2]rotaxane, comprising the pi-electron-donating macrocyclic polyether bis-p-phenylene-34-crown-10 (BPP34C10) and a dumbbell-shaped component that contains 1) a Ru(II) polypyridine complex as one of its stoppers in the form of a photoactive unit, 2) a p-terphenyl-type ring system as a rigid spacer, 3) a 4,4'-bipyridinium unit and a 3,3'-dimethyl-4,4'-bipyridinium unit as pi-electron-accepting stations, and 4) a tetraarylmethane group as the second stopper. The synthesis of the [2]rotaxane was accomplished in four successive stages. First of all, the dumbbell-shaped component of the [2]rotaxane was constructed by using conventional synthetic methodology to make 1) the so-called "west-side" comprised of the Ru(II) polypyridine complex linked by a bismethylene spacer to the p-terphenyl-type ring system terminated by a benzylic bromomethyl function and 2) the so-called "east-side" comprised of the tetraarylmethane group, attached by a polyether linkage to the bipyridinium unit, itself joined in turn by a trismethylene spacer to an incipient 3,3'-dimethyl-4,4'-bipyridinium unit. Next, 3) the "west-side" and "east-side" were fused together by means of an alkylation to give the dumbbell-shaped compound, which was 4) finally subjected to a thermodynamically driven slippage reaction, with BPP34C10 as the ring, to afford the [2]rotaxane. The structure of this interlocked molecular compound was characterized by mass spectrometry and NMR spectroscopy, which also established, along with cyclic voltammetry, the co-conformational behavior of the molecular shuttle. The stable translational isomer is the one in which the BPP34C10 component encircles the 4,4'-bipyridinium unit, in keeping with the fact that this station is a better pi-electron acceptor than the other station. This observation raises the question- can the BPP34C10 macrocycle be made to shuttle between the two stations by a sequence of photoinduced electron transfer processes? In order to find an answer to this question, the electrochemical, photophysical, and photochemical (under continuous and pulsed excitation) properties of the [2]rotaxane, its dumbbell-shaped component, and some model compounds containing electro- and photoactive units have been investigated. In an attempt to obtain the photoinduced abacus-like movement of the BPP34C10 macrocycle between the two stations, two strategies have been employed-one was based fully on processes that involved only the rotaxane components (intramolecular mechanism), while the other one required the help of external reactants (sacrificial mechanism). Both mechanisms imply a sequence of four steps (destabilization of the stable translational isomer, macrocyclic ring displacement, electronic reset, and nuclear reset) that have to compete with energy-wasteful steps. The results have demonstrated that photochemically driven switching can be performed successfully by the sacrificial mechanism, whereas, in the case of the intramolecular mechanism, it would appear that the electronic reset of the system is faster than the ring displacement.     

Self-assembly of 1:2 inclusion complexes between a metallocycle host and dihydroxyaromatic guests: a redox controlled complexation process

Two new 1:2 inclusion complexes were prepared by self-assembly of three components: a ligand based on 4,4'-bipyridinium, a square-planar Pd complex, and a dihydroxyaromatic guest (hydroquinone or 1,5-dihydroxynaphthalene) in a 2:2:2 ratio. Their X-ray structural analyses revealed that the complexes are stabilized by pi-pi stacking and [C-H...pi] interactions.     

某些过渡金属钌配合物非线性光学性能的从头算和密度泛函理论研究

实验发现金属钌的某些配合物具有大的非线性光学性能。我们的理论研究表明 金属钌配合物[Ru(NH_3)_4L~DL~A]~(n+) (n = 2，3；L~D，L~A =吡啶衍生物配体) 的非线性光学性能取决于推电子基团L~D的给电子能力以及拉电子基团L~A的受电子 能力，L~D和L~A的推拉电子越强越有利于提高配合物的二阶非线性光学系数β，因 此带正电荷的L~A能大幅度提高β值。虽然增加共轭体系的长度有利于提高β值， 但在Ru的配合中，吡啶环间或吡淀环与苯环间不一定要保持共面也会有大的β值。 DFT和ab initio方法的计算结果对比表明，对于含过渡金属Ru的化合物，在HF水平 上难以得到满意的结论，由从头算有限场方法计算得到的β值偏小，而用TDDFT方 法能得到可与实验值符合较好的结果。     

Dielectric anisotropy of the single crystal of isopropylviologen copper(I) triiodide

Solvothermal reactions of CuI with isopropanol, 4,4'-bipyridine, I(2) and a small amount of water in MeCN produced one coordination compound [isopropylviologen][CuI(3)] (isopropylviologen = N,N'-diisopropyl-4,4'-bipyridinium) (1). The dielectric constants of the single crystal of 1 along the three crystal axes are different with the largest diversity ratio of ～3.3, showing dielctric anisotropic behavior. Under low temperature (<273 K) or medium electric field frequency range (1 KHz-1 MHz), the dielectric constant of the title compound is nearly unchanged, exhibiting a temperature/frequency-independent characteristics. The crystalline powder of 1 has a low dielectric constant and low dielectric loss in the medium electric field frequency range, which is comparable to the traditional low-k material SiO(2).     

A 3-D Supramolecular Network with 1-D Cation Metal.organic Coordination Polymers and Diverse Motifs from Hydrogenbonded [M（H2O）4]-Carboxylates

One-pot solvothermal reaction of Iransition metal Znn salt with 4,4-bipyddyl （bpy） and 1,4-benzenediacrylic add （H2L） in the presence of Et3N generates a three-dimensional （3-D） supramolecular network with 1-D cation metal-organic coordination polymer, [Zn（H20）a（bpy）]-L 1, and structurally characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, and photoluminescent property. The complex crystallizes in triclinic, space group P1 with a = 7.1291（2）, b = 7.3784（3）, c = 10.5042（3）A, α = 95.049（2）, β = 102.162（2）, 7 = 97.027（3）0, V= 532.38（3）A3, C22H24N2O8Zn, Mr = 509.82, De= 1.590 g/cm3, p（MoKa）= 1.207 ram-l, F（000） = 264, Z = 1,the finalR=O.0438and wR=O.lOll for 1589 observed reflections （I 〉 2σ（I））. In the crystal structure, the second building unit composed of [Zn（H2O）4].L constructs two distinct 2-D supramolecular sheets and a neutral 3-D architecture. The title compound 1 shows strong photoluminescence with emission maximum at 2 = 455 nm upon λex.max = 355 nm.     

Novel 3-D Supramolecular Architectures Constructed from Zn^2＋ ions, Oxybis（4-benzoate） and Di（2-pyridyl）amine Ligands

Using the V-shaped oba dianions as bridging ligands and dpa molecules as terminal ligands, a new 1D helical coordination-polymeric chain, [Zn（oba）（dpa）]n [oba=oxybis（4-benzoate）, dpa=di（2-pyridyl）amine], was synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, UV-Vis and IR spectra, and TGA analysis. X-ray structural analysis revealed that, oba and dpa ligands played an important role in the self-assembly of the helical chains by providing potential supramolecular recognition sites for π-π aromatic stacking and hydrogen-bond interactions, resulting in the self-assembly of the （4,4） networks to give a 3-D supramolecular framework. The photoluminescence properties of the title compound were also investigated, showing intense blue photoluminescence properties at room temperature.     

Hydrothermal Synthesis,Crystal Structure and Magnetic Properties of a Cobalt(II) Coordination Polymer Assembled by 4-Sulfophthalate and 4,4'-Bipyridine

1 INTRUDUCTION The rational design and synthesis of metal-direc- ted supramolecular framework have received much attention in coordination chemistry because of their potential applications in catalysis, molecular selec- tion, non-linear optics, ion exchange and microelec- tronics[1～4]. During the lastdecade, many high-di- mensional coordination complexes have been de- signed and prepared through molecular self-as- sembly process[5～10]. The construction of open metal organic framework, s…     

A Novel 3D Supramolecular Network Constructed from [Cu(4,4'-bipyridine)(O_2CMe)_2]_2 Molecular Ladders by Hydrogen Bonding

1 INTRODUCTION In recent years, the assembly of extended supra- molecular architectures from molecular building units has yielded a new generation of materials with diverse network topologies[1～3]. A number of such frameworks have been found to exhibit fascinating physical and chemical properties. The investigation of hydrogen bonding is important for many practical applications, such as the design of antibiotics and development of new materials with programmed properties[4]. A great va…     

3]Pseudorotaxane-like complexes formed between bipyridinium dications and bis-p-xylyl[26]crown-6

[structure: see text]. The crown ether BPX26C6 forms a [3]pseudorotaxane-like complex with the N,N'-dimethyl-4,4'-bipyridinium dication both in solution and in the solid state. The facile one-pot synthesis of a [2]rotaxane from neutral precursors-BPX26C6, 4,4'-dipyridyl, and 3,5-di-tert-butylbenzyl bromide-suggests that BPX26C6 may bind to (mono)pyridinium cations in a [2]pseudorotaxane-like manner.     

A molecular plug-socket connector

A monocationic plug-socket connector that is composed, at the molecular level, of three components, (1) a secondary dialkylammonium center (CH2NH2+CH2), which can play the role of a plug toward dibenzo[24]crown-8 (DB24C8), (2) a rigid and conducting biphenyl spacer, and (3) 1,4-benzo-1,5-naphtho[36]crown-10 (BN36C10), capable of playing the role of a socket toward a 4,4'-bipyridinium dicationic plug, was synthesized and displays the ability to act as a plug-socket connector. The fluorescent signal changes associated with the 1,5-dioxynaphthalene unit of its BN36C10 portion were monitored to investigate the association of this plug-socket connector with the complementary socket and plug compounds. The results indicate that (1) the CH2NH2+CH2 part of the molecular connector can thread DB24C8 in a trivial manner and (2) the BN36C10 ring of the connector can be threaded by a 1,1'-dioctyl-4,4'-bipyridinium ion only after the CH2NH2+CH2 site is occupied by a DB24C8 ring. The two connections of the three-component assembly are shown to be controlled reversibly by acid/base and red/ox external inputs, respectively. The results obtained represent a key step for the design and construction of a self-assembling supramolecular system in which the molecular electron source can be connected to the molecular electron drain by a molecular elongation cable.     

Synthesis of tripodal [2]rotaxanes: high concentration principlet

Symmetrical and non-symmetrical tripodal [2]rotaxanes (1) incorporating 1,1'-disubstituted-4,4'-bipyridinium cations (2) and 34-crown-10 (3) have been prepared directly from 4,4'-bipyridine or from monocationic intermediates in high yields at room temperature and atmospheric pressure under conditions that permit the use of high reagent concentrations (0.1-0.2 M, 150-200 g(-1)).     

Reading the operation of an acid/base-controllable molecular switch by naked eye

We report a pH-controllable molecular switch whose switching can be monitored by the naked eye; this system involves the formation of a complex between a [2]rotaxane--featuring dibenzylammonium and 4,4'-bipyridinium stations--and a TTF-side-walled molecular clip.     

An integrated relay/nitrate reductase field-effect transistor for the sensing of nitrate (NO3-)

An integrated enzyme-functionalized field-effect transistor (ENFET) device for the sensing of nitrate ions is described. An aminosiloxane-functionalized gate interface is modified with N-methyl-N'-(carboxyalkyl)-4,4'-bipyridinium relay units. The complex formed between nitrate reductase and the bipyridinium units on the gate surface is crosslinked with glutaric dialdehyde to yield a stable relay-enzyme layer on the gate interface. In the presence of sodium dithionite as electron donor, the biocatalyzed reduction of nitrate to nitrite ion is stimulated. The ratio between the oxidized and reduced states of the bipyridinium sites regulates the gate potential, and is controlled by the concentration of NO3- ions in the system. The effect of the chain length tethering the N-methyl-N'-(carboxyalkyl)-4,4'-bipyridinium units to the gate surface on the biocatalyzed reduction of NO3- ions, and on the NO3- FET sensor performance is discussed. The devices that include the bipyridinium units tethered to the gate interface with methylene chain length, -(CH2)n, where n > or = 7, reveal a detection limit of 7 x 10(-5) M for nitrate and a sensitivity of 52 +/- 2 mV dec-1. The response time of the device is as low as 50 s, and the operational time of the system is ca. 85 s. We estimate the surface coverage of nitrate reductase on the gate surface to be ca. 1.2 x 10(-12) mol cm-2.     

Effect of alkali metal ions on photochromic behavior of bisviologen-incorporated oligo-oxyethylene units

Two bisviologen derivatives, 1,11-bis(N-propyl-4,4'-bipyridinium)-3,6,9-trioxaundecane tetrakis-(hexafluorophosphate) (1) and 1,8-bis(N-propyl-4,4'-bipyridinium)-3,6-dioxaoctane tetrakis-(hexafluorophosphate) (2), each incorporating trioxaundecane and dioxaoctane groups between two viologen units, respectively, were prepared so that their photochromic behavior in the absence and the presence of alkali metal ions in a thin polymer film could be investigated. Photoirradiation of the films containing 1 and 2 caused color changes from pale yellow to blue, associated with the photoinduced reduction of the viologen units from the dication to the radical cation. The addition of alkali metal ions, especially, K+ and Na+, caused change in the spectra of the photoreduced viologen radical cation for 1 and 2, respectively, because of the increase in the fractional amplitude for the dimer component of the radical cation rather than the monomer one. This may be related to the guest-induced conformational change of 1 and 2, in which the alkali metal ion is surrounded by the oligo-oxyethylene unit of 1 and 2. The regulation in photochromic properties of viologen derivatives can be achieved by addition of alkali metal ions.