An unusual polyoxometalate-encapsulating 3D polyrotaxane framework formed by molecular squares threading on a twofold interpenetrated diamondoid skeleton.

Threading molecular square "beads" on a twofold interpenetrated diamondoid skeleton gives a new type of 3D metal-organic polyrotaxane framework with large channels, in which nanosized Keggin anions as guests are encapsulated for the first time.

A theoretical exploration of the effect of fluorine and cyano substitutions in diketopyrrolopyrrole-based polymer donor for organic solar cells.

A series of polymer donor materials 1-5 based on diketopyrrolopyrrole and thiophene unit which have been widely used in organic solar cells (OSCs) were investigated based on quantum chemical calculations. The effect of fluorine and cyano substitutions in polymer donor materials was focused on. Based on the investigation on electronic structures and optical properties of the reported molecules 1 and 2 and the analysis on some parameters relevant to charge dissociation ability at donor/acceptor interface constituted by 1 and 2 with PC61BM such as intermolecular charge transfer and recombination, driving force and Coulombic bound energy, we explained why fluorine substitution can improve OPV efficiency through strengthening eletron-withdrawing ability from a theoretical perspective. Then we designed cyano-substituted polymers 3-5 with the aim of obtaining better photovoltaic donor materials. The results reveal that our attempt to design donor materials which can balance large open-circuit voltage (Voc) and high short-circuit current (Jsc) in OSCs has worked out. It is worth noting that the substitutions of fluorine and cyano groups synergistically reduce energy gap and HOMO energy level of polymers 3 and 4. Moreover, 3/PC61BM and 4/PC61BM heterojunctions show over 107 and 104 times higher than 1/PC61BM on the ratios of intermolecular charge transfer and recombination rates (kinter-CT/kinter-CR). Thus, our work here may provide an efficient strategy to design promising donor materials in OPVs and we hope it could be useful in the future experimental synthesis.

Metal-organic frameworks as potential drug delivery systems.

INTRODUCTION: Metal-organic frameworks (MOFs) are a unique class of hybrid porous solids based on metals and organic linkers. Compared to traditional porous materials, they possess predominance of large surface areas, tunable pore size and shape, adjustable composition and functionalized pore surface, which enable them unique advantages and promises for applications in adsorption and release of therapeutic agents. AREAS COVERED: This review addresses MOFs as a new avenue for drug delivery and exhibits their ability to efficiently deliver various kinds of therapeutic agents. It also details the requirements that MOFs need to satisfy for biomedical application, such as toxicological compatibility, stability, particle size, and surface modification. In addition, several approaches used to enhance encapsulation efficiency are summarized and parameters influencing delivery efficiency are also discussed. EXPERT OPINION: Benefiting from the unique advantages of MOFs materials, efficient delivery of various kinds of drugs has been achieved in some MOF materials. However, it is only the outset of MOFs in drug delivery system, and numerous work need to be done before clinical applications, for example, studying their in vivo toxicity, exploring degradation mechanisms so as to establish real stability of MOFs in body's liquid, providing appropriated surface modification avenue for MOFs, and researching in vivo efficiency and pharmacokinetics of drug-loaded MOFs.

TDDFT studies on electronic structures, chiroptical properties and solvent effect on the CD spectra of diphosphonate-functionalized polyoxomolybdates.

The ultraviolet-visible and electronic circular dichroism (UV-vis/ECD) spectra of diphosphonate-functionalized asymmetric cantilever-type chiral polyoxomolybdate (POM) enantiomer R-{Mo2O5[(Mo2O6)NH3CH2CH2CH2C(O)(PO3)2]2}(6-) (R) were systematically investigated using time-dependent density functional theory (TDDFT) method. From the view of molecular structure and relative energy, we inferred that there is likely a structural conversion from enantiomers R to S-{Mo2O5[(Mo2O6)NH3CH2CH2CH2C(O)(PO3)2]2}(6-) (S) via the intermediate configuration (IN). The ECD spectra of the enantiomer R were produced over the range of 3.0-6.3eV. The UV-vis and ECD spectra of enantiomer R in the gas phase and different solvents were calculated. The results reveal that the UV-vis and ECD spectra of the chiral POM in gas phase, polar solvent, or non-polar solvent are different. The calculated electron density difference maps (EDDMs) display that the POM cluster is a chiroptical chromophore in studied compound.

TDDFT studies on the structures and ECD spectra of chiral bisarylimidos bearing different lengths of o-alkoxy chain-substituted polyoxomolybdates.

The chiroptical properties of bisarylimidos bearing o-alkoxy chain-substituted polyoxomolybdates [Mo(6)O(17)(2,2'-NC(6)H(4)OC(n)H(2n)OC(6)H(4)N)](2-) [n=4(2), 6(3±), 8(4)] were investigated using the time-dependent density functional method. The results showed that the studied chiral polyoxometalates (POMs) manifested similar absorption sites but displayed different shapes and magnitudes in their electronic circular dichroism (ECD) spectra. The ECD spectra of the studied chiral POMs originated from charge-transfer (CT) transitions from arylimido fragments to the POM cages and from oxygen atoms to the molybdenum atoms in the POM cages. The o-alkoxy chain served as a scaffold for generating chirality rather than contributing to the ECD spectrum of the studied POMs. The induced chiralities of the POM cages were defined by the CT transitions, which were completely localized on the POM cages. Furthermore, the long-range corrected CAM-B3LYP hybrid functional and a basis set that is larger than Lanl2DZ should be used for ECD calculations of chiral POMs. Our work establishes the use of computational studies to investigate the chiroptical properties of chiral POMs and provides theoretical interpretations.

Inorganic-organic hybrid materials with different dimensions constructed from copper-fluconazole metal-organic units and Keggin polyanion clusters.

Inorganic-organic hybrid materials based on Keggin polyoxometalate building blocks combined with Cu(II)/Cu(I) and flexible fluconazole ligand [1-(2,4-difluorophenyl)-1,1-bis[(1H-1,2,4-triazol-1-yl)methyl]methanol] (Hfcz) have been obtained by hydrothermal methods, namely, [Cu(II)(2)(Hfcz)(4)(SiW(12)O(40))].3H(2)O (1), [Cu(II)(4)(fcz)(4)(H(2)O)(4)(SiMo(12)O(40))].6H(2)O (2), [Cu(II)(2)(fcz)(2)][Cu(II)(4)(fcz)(4)(SiW(12)O(40))][Cu(II)(2)(fcz)(2)(H(2)O)(2)(SiW(12)O(40))].6H(2)O (3), (Et(3)NH)(2)[Cu(I)(2)(Hfcz)(2)(SiW(12)O(40))].2H(2)O (4), (Et(3)NH)(2)[Cu(I)(2)(Hfcz)(2)(SiW(12)O(40))].H(2)O (5) and [Cu(I)(4)(Hfcz)(4)(SiMo(12)O(40))] (6). Their structures have been determined by single-crystal X-ray diffraction analyses, and the compounds are further characterized by elemental analyses, IR spectra and thermogravimetric (TG) analyses. In 1, Cu(II) cations are bridged by fluconazole ligands to form a 3D lvt coordination polymeric network, which is connected by (SiW(12)O(40))(4-) anions to form a complicated 3D (4,6)-connected framework with the topology of (4(2).6(4))(4(6).6(7).8(2))(2). In 2, two fcz(-) anions chelate two Cu(2+) cations to form a [Cu(fcz)](2)(2+) dimer, which is bridged by (SiW(12)O(40))(4-) polyanions to generate a 2D (4,4) grid. Compound 3 is formed by three types of co-crystallizing subunits including a dimer [Cu(fcz)](2)(2+), a dumbbell molecule [Cu(4)(fcz)(4)(SiW(12)O(40))] and an infinite chain {[Cu(2)(fcz)(2)(H(2)O)(2)(SiW(12)O(40))](2-)}(infinity). In compounds 4 and 5, Hfcz ligands link Cu(+) cations to generate 1D coordination polymeric units, and (SiW(12)O(40))(4-) polyanions connect these metal-organic units to form two types of (6(3)) sheets which are topological isomerism. In compound 6, (SiMo(12)O(40))(4-) polyanions fixed in Cu(I)-Hfcz square rings are further extended into a 2D sheet via linking Cu(I) atoms of different rings. By carefully inspection of the structures of 1-6, it is believed that various transition-metal organic units and Keggin polyanions with different coordination modes are important for the formation of the different structures. In addition, electrochemical behaviors of compounds 1, 2, 5 and 6 have been investigated.

d(10)-Metal coordination polymers based on analogue di(pyridyl)imidazole derivatives and 4,4'-oxydibenzoic acid: influence of flexible and angular characters of neutral ligands on structural diversity.

A series of mixed-ligand coordination complexes, namely [Zn(L(1))(oba)] (), [Cd(L(1))(oba)] (), [Zn(2)(L(2))(oba)(2)].8H(2)O (), [Cd(2)(L(2))(oba)(2)].2H(2)O (), [Zn(3)(L(3))(oba)(3)] (), [Cd(2)(L(3))(oba)(2)].(L(3)) (), [Cd(L(4))(oba)].H(2)O () and [Cd(L(5))(oba)].3H(2)O (), where L(1) = 2-(2-pyridyl)imidazole, L(2) = 1,4-bis[2-(2-pyridyl)imidazol-1-yl]butane, L(3) = 1,4-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, L(4) = 1,3-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, L(5) = 1,2-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene and H(2)oba = 4,4'-oxydibenzoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. In compounds and , oba(2-), L(1) ligand and Zn(II) or Cd(II) ions assemble to form the parallel chains or parallel sheets which are linked by the weak hydrogen bonding and pipi stacking interactions to give the 2D supramolecular sheet or 3D supramolecular net, respectively. For , L(2) ligands connect [Zn(oba)] chains to generate a unusual (10,3)-b topological structure which is the first example for eight-fold interpenetrating framework based on the (10,3)-b net. In , L(2) ligands link [Cd(oba)] double-chains to give a 2D sheet which is assembled by pipi stacking interactions to obtain a 3D supramolecular net. In , L(3) ligands link Zn(II) ions from alpha-Po net formed by Zn(II) ions and oba(2-) anions to show a novel 3D 8-connected self-penetrating framework with the unreported (4(16).6(11).8) topological structure. In , the double-chains constructed by Cd(II) and oba(2-) anions are linked by one kind of L(3) ligand to form a layer-like structure which is assembled by pipi stacking interactions to show a 3D supramolecular structure. In , oba(2-) anions coordinate to Cd(II) cations to form chains which are connected by L(4) to form a four-fold interpenetrating diamond network. In , the weak hydrogen bonding and pipi stacking interactions connect the [Cd(L(5))(oba)] chains to give a 2D supramolecular sheet. By careful inspections of the structures of , we believe that the different flexible and angular neutral ligands, coordination geometries of metal centers and weak interactions (hydrogen bonds and pipi stacking interactions) are crucial factors for the formation of the different structures. The photoluminescent properties of have been studied in the solid state at room temperature.

Syntheses and characterization of six coordination polymers of zinc(II) and cobalt(II) with 1,3,5-benzenetricarboxylate anion and bis(imidazole) ligands.

Six new coordination polymers, namely [Zn1.5(BTC)(L1)(H2O)2].1.5H2O (1), [Zn3(BTC)2(L2)3] (2), [Zn3(BTC)2(L3)1.5(H2O)].H2O (3), [Co6(BTC)4(L1)6(H2O)3].9H2O (4), [Co1.5(BTC)(L2)1.5].0.25H2O (5), and [Co4(BTC)2(L3)2(OH)2(H2O)].4.5H2O (6), where L1 = 1,2-bis(imidazol-1-ylmethyl)benzene, L2 = 1,3-bis(imidazol-1-ylmethyl)benzene, L3 = 1,1'-(1,4-butanediyl)bis(imidazole), and BTC = 1,3,5-benzenetricarboxylate anion, were synthesized under hydrothermal conditions. In 1-6, each of L1-L3 serves as a bidentate bridging ligand. In 1, BTC anions act as tridentate ligands, and compound 1 shows a 2D polymeric structure which consists of 2-fold interpenetrating (6, 3) networks. In compound 2, BTC anions coordinate to zinc cations as tridentate ligands to form a net with (64.82)2(86)(62.8)2 topology. In compound 3, BTC anions act as tetradentate ligands and coordinate to zinc cations to form a net with (4.62.83)2(8.102)(4.6.83.10)2 topology. In compound 5, each BTC anion coordinates to three Co cations, and the framework of 5 can be simplified as (64.82)2(62.82.102)(63)2 topology. For 4 and 6, the 2D cobalt-BTC layers are linked by bis(imidazole) ligands to form 3D frameworks. In 6, the Co centers are connected by micro3-OH and carboxylate O atoms to form two kinds of cobalt-oxygen clusters. Thermogravimetric analyses (TGA) for these compounds are discussed. The luminescent properties for 1-3 and magnetic properties for 4-6 are also discussed in detail.

Syntheses and structures of organic-inorganic hybrid compounds based on metal-fluconazole coordination polymers and the beta-Mo8O26 anion.

Five organic-inorganic hybrid compounds, namely, [Co2(fcz)4(H2O)4][beta-Mo8O26].5H2O (1), [Ni2(fcz)4(H2O)4][beta-Mo8O26].5H2O (2), [Zn2(fcz)4(beta-Mo8O26)].4H2O (3), [Cu2(fcz)4(beta-Mo8O26)].4H2O (4), and [Ag4(fcz)4(beta-Mo8O26)] (5), where fcz is fluconazole [2-(2,4-difluorophenyl)-1,3-di(1H-1,2,4-triazol-1-yl)propan-2-ol], were synthesized under hydrothermal conditions, and crystal structures of 1-5 have been determined by X-ray diffraction. In compounds 1 and 2, metal cations are linked by fluconazole ligands to form hinged chain structures and [beta-Mo8O26]4- anions act as counterions. In compound 3, Zn(II) cations are bridged by fluconazole ligands to form 2D (4,4) networks, and each pair of these networks is linked by [beta-Mo8O26]4- anions to form a sandwich double-layer structure. In compound 4, Cu(II) cations are bridged by fluconazole ligands to form 2D (4,4) networks, and these networks are connected by [beta-Mo8O26]4- anions to form a 3D framework. In compound 5, AgI cations and [Ag2]2+ units are bridged by fluconazole ligands to form 2D Ag-fcz layers, and these layers are further connected by [beta-Mo8O26]4- anions to form a complicated 3D structure with the topology of (7(2).8(1))2(7(3).8(3))(7(2).8(11).10(1).12(1))2. Thermogravimetric analyses for these compounds are also discussed in detail. The complexes exhibit antitumor activity in vitro, as shown by MTT experiments.