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Four cubane-like [Cu.sub.4][I.sub.4] units are assembled around an iodine atom to form the giant, mixed-valent [Cu.sup.II][Cu.sub.15.sup.I][I.sub.17] cluster. The [Cu.sup.II][Cu.sub.15.sup.I][I.sub.17] cluster and a bipyrazole linker has formed a 3-dimensional (3D) open framework with paramagnetic and thermochromic properties.

The article presents a new approach, which utilizes the N...N coupling of different (salen)ruthenium(VI) nitrides for the general synthesis of the (salen)ruthenium(III) complexes. These ruthenium salen complexes are shown to be widely used as the catalysts in different organic transformations.

The thiourea/Au[Cl.sub.3]/AgOTf-catalyzed annulations of aryl epoxides under mild conditions were employed to perform synthesis of structurally diverse catechins. The newly developed diversity-oriented protocol provides a highly efficient route to a library of catechins-derived natural products such as anti-HIV agent 8-C-ascorbyl-(-)-epigallocatechin.

The synthesis, crystal structures, and variable-temperature solid luminescence of copper(I) trimer, [[Cu(Ppz)].sub.3] and a polymer, {[[Cu(Ppz)].sub.3][[CuCN].sub.3]} both containing the [Cu(Ppz)].sub.3] entity as a building block are described. The products are obtained by solvothermal reactions of 4(pyrid-4'-yl)-3,5-dimethylpyrazole (HPpz) with CuBr in two mixed solvents, N[H.sub.3]*[H.sub.2]O/EtOH and N[H.sub.3]*[H.sub.2]O/MeCN.

The aerobic oxidation of the N-hydroxyguanidinum moiety of N-hydroxyarginine to NO is a key step in the biosynthesis of NO by the enzyme nitric oxide synthase (NOS). So far, there is no chemical system that can efficiently carry out similar aerobic oxidation to give NO. We report here the synthesis and X-ray crystal structure of an osmium(III) N-hydroxyguanidine complex,mer-[OsIII{NH-C(NH2)(NHOH)}(L)(CN)3]- (OsGOH, HL = 2-(2-hydroxyphenyl)benzoxazole), which to the best of our knowledge is the first example of a transition metal N-hydroxyguanidine complex. More significantly, this complex readily undergoes aerobic oxidation at ambient conditions to generate NO. The oxidation is pH-dependent; at pH 6.8, fac-[Os(NO)(L)(CN)3]- is formed in which the NO produced is bound to the osmium center. On the other hand, at pH 12, aerobic oxidation of OsGOH results in the formation of the ureato complex [OsIII(NHCONH2)(L)(CN)3]2- and free NO. Mechanisms for this aerobic oxidation at different pH values are proposed. [ABSTRACT FROM AUTHOR]

Three sandwich-type inorganic-organic hybrid solids based on iso-polyvanadate cluster, {V4O12}4-, {H2V6O18}4-, or {H2V10O28}4-, and decamethylcucurbit[5]uril (Me10CB[5]) have been synthesized under hydrothermal conditions. In the structures of (NH4)4[(V4O12)·(Me10CB[5]@0.5H2O)2]·∼15H2O (1) and (NH4)4[(H2V10O28)·(Me10CB[5]@H2O)2]·∼16H2O (3), tetranuclear {V4O12}4- or decanuclear {H2V10O28}4- clusters are sandwiched by (NH4)2@Me10CB[5] closed molecular capsules, through hydrogen-bonding interactions, whereas compound 2, formulated as Li4(H2O)6[(H2V6O18)·(Me10CB[5]@H2O)2]·∼14H2O, is built by hexanuclear {H2V6O18}4- clusters that are covalently sandwiched by Li2@Me10CB[5] half-open molecular capsules in a way similar to thoset of 1 and 3. Compounds 1-3 represent rare examples of sandwich-type polyoxometalate (POM)-based materials in which POM units are inserted at the inner sphere by either hydrogen or covalent bonds. Compound 2 has shown rational photocatalytic activity toward the degradation of methyl orange solutions under visible light. [ABSTRACT FROM AUTHOR]

Recently, capturing or transforming greenhouse gases, such as CO2 and N2O, have attracted considerable interest from the perspective of environmental protection. In the present work, by studying CO2 and N2O adsorption on pristine and calcium (Ca)-decorated fullerenes (C60) with density functional theory (DFT) methods, we have evaluated the potential application of this Cfco'based complex for the capture of CO2 and transformation of N2O. The results indicate that the adsorptions of CO2 and N2O molecules on the pristine C60 are considerably weak accompanied by neglectable charge transfer. When CM is decorated with Ca atoms, however, it is found that CO2 and N2O adsorptions on the C«j are greatly enhanced. Up to 6ve CO2 molecules can be adsorbed on the CaC60) system due to the electrostatic interaction. For N2O molecule, it is first molecularly adsorbed on the Ca atom with the adsorption energy of - 0.534 eV, followed by the N2 formation with a low barrier and high exothermicity. Moreover, when four Ca atoms are decorated on the surface of C60, the maximum number of the adsorbed CO2 molecules is 16. Our results might be userul not only to widen the potential applications of fullerene but also to provide an effective method to capture or transform greenhouse gases. [ABSTRACT FROM AUTHOR]

A family of inorganic−organic hybrid solid materials has been assembled from presynthesized organic decamethylcucurbit[5]uril (Me10Q[5]) macrocycles and the well-known inorganic polyoxometalate (POM) clusters. Three compounds, formulated as [Na6(H2O)11(Me10Q[5])2]·[β-H2W12O40]·5H2O (1), [Na4(H2O)7(Me10Q[5])2]·[α-SiW12O40]·20H2O (2), and [Na4(H2O)7(Me10Q[5])2]·[β-SiW12O40]·13H2O (3) are reported. In the molecular structures of the three compounds, versatile Keggin-type polyoxotungstate clusters were successfully assembled as inorganic building blocks to build hybrid materials with Me10Q[5]. Compound 1 comprises β-Keggin-type iso-polyoxotungstate [H2W12O40]6− clusters and Me10Q[5]. Compound 2 contains α-Keggin-type [SiW12O40]4− heteropolyanions and Me10Q[5], whereas compound 3 is constructed from β-Keggin-type heteropolyoxosilicotungstate clusters [SiW12O40]4− and Me10Q[5]. All of the compounds feature train-like structural subunits based on central POM/alkali metal backbones and two side rows of parallel Me10Q[5] macrocycles. Three novel complexes constructed from decamethylcucurbit[5]uril (Me10Q[5]) and Keggin-type polyoxotungstates are reported. All of the compounds feature train-like structural subunits based on central POM/alkali metal backbones and two side rows of parallel Me10Q[5] macrocycles. [ABSTRACT FROM AUTHOR]

An efficient and rapid solution-phase combinatorial synthesis of the SAG library was developed. The salient features for this library synthesis is the application of carbothioamide-derived palladacycle-catalyzed Suzuki coupling reactions for the parallel synthesis of a series of pyridine-based biaryl aldehydes under aerobic conditions and a direct N-alkylation of carbamates using NaH as base in DMF in the presence of catalytic amount of water. The resultant library has been submitted to biological screening to evaluate their potential role in the regulation of Hedgehog pathway. [ABSTRACT FROM AUTHOR]

The smallest members of the cucurbituril family, cucurbit[5]uril and the alkyl-cucurbit[5]urils, can be used as a building blocks, linked by metal ions to create supramolecular rings. The cavities found at the center of these rings have dimensions between 7 and 19 Å in width and 8.5 Å in depth. The partially substituted alkyl-cucurbit[5]urils present the most interesting supramolecular ring formation. This occurs as a result of selective coordination of metal ions to the carbonyl oxygens of the glycoluril moieties carrying alkyl substitution. [ABSTRACT FROM AUTHOR]

A practical one-pot synthetic strategy for the efficient synthesis of a range of structurally interesting and bioactive quinoline-based tetracycles has been developed. A key step in the synthesis is a tandem three-component reaction of heteroaromatic amine, methyl 2-formylbenzoate and tbutyl isonitrile, followed by TFA-mediated lactamization via intramolecular aminolysis of an adjacent ester. Results related to a kinase-panel screening for several selected compounds are also discussed in this article. [ABSTRACT FROM AUTHOR]

Three new coordination polymers, Zn(H2Bpz)(Tph)·1/2(H2Bpz)n(1), Zn2(H2Bpz)(Bpz)(Iph)n (2), and Zn2(H2Bpz)(HBtc)2(H2O)2·7/6(H2O)n (3) (H2Bpz 3,3‘,5,5‘-tetramethyl-4,4‘-bipyrazole; H2Tph terephthalic acid; H2Iph isophthalic acid; H3Btc benzene-1,3,5-tricarboxylic acid), have been isolated from parallel hydrothermal reactions of ZnSO4and H2Bpz with H2Tph, H2Iph, and H3Btc, respectively. These crystalline solids have been structurally defined, of which 1was revealed to construct in a 3D architecture with porosity. Interestingly, because of its large porosity, 1allows the concurrent 2-fold interpenetration and inclusion of free H2Bpz as guest molecule. In contrast to 1, polymer 2structures in a 2D framework of note for containing both neutral and deprotonated H2Bpz as 2-and 4-bridging linkers, respectively. This case demonstrates a rare usage of H2Bpz as ligand in the construction of MOFs. The partial deprotonation of H2Bpz may be a consequence of less acidity of H2Iph than H2Tph, by which the influence of a second ligand on the reactivity of the main ligand is reified. Likewise, 3is also assembled in a 2D framework, containing H2Bpz and monoacid HBtc2-as ligands, which indicates the stronger acidity of H3Btc. Moreover, to probe the effect of substitution of second ligands, we have investigated the luminescence of 1−3in the solid state at room temperature, revealing that the polymers are photoluminescent and their emissions are varied with the alteration of second ligands. [ABSTRACT FROM AUTHOR]

Four cubane-like Cu4I4 units are assembled around an iodine atom to form the giant, mixed-valent CuIICuI15I17 cluster. The CuIICuI15I17 cluster and a bipyrazole linker form a 3D open framework with paramagnetic and thermochromic properties. This paper also touches on the resemblance of this cluster to the self-similar object of a Sierpinski tetrahedron. [ABSTRACT FROM AUTHOR]

We reported a one-pot enantioselective three-component vinylogous Michael/aldol tandem reaction of prochiral 3-alkylidene oxindoles with methyleneindolinones and aldehydes using bifunctional organocatalysts. A variety of enantioenriched 3,3-disubstituted oxindoles 3 and spirolactones 4 were generated in moderate yields (up to 78%) with high stereoselectivities (up to >20:1 dr, >99% ee). Intriguingly, we observed that the aldol reaction with paraformaldehyde generates 3,3-disubstituted oxindoles 3 bearing a hydroxymethyl group, while the reaction with aliphatic aldehydes generates spirolactones 4 .

Sulfonylureas and glinides are commonly used oral insulin secretagogues (ISs) that act on the pancreatic ATP-sensitive potassium (K ATP ) channel to promote insulin secretion in order to lower the blood glucose level. Physiologically, K ATP channels are inhibited by intracellular ATP and activated by Mg-ADP. Therefore, they sense the cellular energy status to regulate the permeability of potassium ions across the plasma membrane. The pancreatic K ATP channel is composed of the pore-forming Kir6.2 subunits and the regulatory SUR1 subunits. Previous electrophysiological studies have established that ISs bind to the SUR1 subunit and inhibit the channel activity primarily by two mechanisms. First, ISs prevent Mg-ADP activation. Second, ISs inhibit the channel activity of Kir6.2 directly. Several cryo-EM structures of the pancreatic K ATP channel determined recently have provided remarkable structural insights into these two mechanisms.

A unique, dual-function, photoactivatable anticancer prodrug, RuEuL, has been tailored that features a ruthenium(II) complex linked to a cyclen-europium chelate via a π-conjugated bridge. Under irradiation at 488 nm, the dark-inactive prodrug undergoes photodissociation, releasing the DNA-damaging ruthenium species. Under evaluation-window irradiation (λ irr = one-photon 350 nm or two-photon 700 nm), the drug delivery process can be quantitatively monitored in real-time because of the long-lived red europium emission. Linear relationships between released drug concentration and ESI-MS or luminescence responses are established. Finally, the efficiency of the new prodrug is demonstrated both in vitro RuEuL anticancer prodrug over some existing ones and open the way for decisive improvements in multipurpose prodrugs.

Monodispersed silver nanoparticles (Ag(0) NPs) have been first prepared on the basis of a postsynthesis via mild reduction from a new crystalline supramolecular hybrid solid assembled from Ag(+) ions and decamethylcucurbit[5]uril (Me10CB[5]). Uniform growth of nearly spherical Ag(0) NPs with an average size of ca. 4.4 nm was observed on the organic Me10CB[5] support to form Ag@Me10CB[5] composite material. The as-synthesized composite material was characterized by a range of physical measurements (PXRD, TGA, XPS, ICP, TEM, etc.) and was further exploited as a heterogeneous catalyst for the reduction of various nitrophenols in the presence of NaBH4. The kinetics of the reduction process was monitored under various experimental conditions. The Ag@Me10CB[5] composite material showed excellent catalytic performance over the reduction reactions and remained active after several consecutive cycles.

Density functional theory (DFT) calculations were performed on the NO reduction on the silicon (Si)-doped graphene. The results showed that monomeric NO dissociation is subject to a high barrier and large endothermicity and thus is unlikely to occur. In contrast, it was found that NO can easily be converted into N2O through a dimer mechanism. In this process, a two-step mechanism was identified: (i) the coupling of two NO molecules into a (NO)2 dimer, followed by (ii) the dissociation of (NO)2 dimer into N2O + O(ad). In the energetically most favorable pathway, the trans-(NO)2 dimer was shown to be a necessary intermediate with a total energy barrier of 0.464 eV. The catalytic reactivity of Si-doped graphene to NO reduction was interpreted on the basis of the projected density of states and charge transfer.

Six water-soluble free-base porphyrin-Ru(II) conjugates, 1-3, and Zn(II) porphyrin-Ru(II) conjugates, 4-6, with different linkers between the hydrophobic porphyrin moiety and the hydrophilic Ru(II)-polypyridyl complex, have been synthesized. The linear and two-photon-induced photophysical properties of these conjugates were measured and evaluated for their potential application as dual in vitro imaging and photodynamic therapeutic (PDT) agents. Conjugates 1-3, with their high luminescence and singlet oxygen quantum yields, were selected for further study of their cellular uptake, subcellular localization, and cytotoxic and photocytotoxic (under linear and two-photon excitation) properties using HeLa cells. Conjugate 2, with its hydrophobic phenylethynyl linker, was shown to be highly promising for further development as a bifunctional probe for two-photon (NIR) induced PDT and in vitro imaging. Cellular uptake and subcellular localization properties were shown to be crucial to its PDT efficacy.

Immunoprecipitation combined with mass spectrometry (MS) is a promising technique for targeting proteomics in characterizing submicrograms of target protein and interacting proteins in living cells. This method, however, is limited by interference arising from nonspecific binding. We report a novel gold nanoparticle (AuNP)-based immuno probe approach for immunoprecipitation. By cross-linking the antibody Fc domain to protein G covalently modified on AuNPs, the probe was fabricated and characterized to have 60 protein G and 30 immunoglobins per AuNP. We used human immunoglobin against the target and mouse immunoglobin with the same isotype (IgG) to fabricate the target and preclear probe, respectively, and termed it as the dual probe approach. Our results showed that the preclear probe (AuNP-IgG) and the target probe (AuNP-anti-ERα) share a similar panel of nonspecific binders but dramatic different specificity toward the target. Thus, using the dual probe method, we showed major nonspecific binders in the cell lysate could be largely removed without sacrificing the target protein. Compared to the conventional agarose gel-chromatography, the AuNP-based probe exhibited less nonspecific interference and higher recovery yield for ERα. Moreover, the AuNP-based probe is more inert than the agarose gel under harsh conditions and does not induce dissociation of the cross-linked IgG that could interfere with target identification. Using AuNP-based dual probes, ERα was shown to be purified from MCF-7 cells with minimum nonspecific binding. Moreover, the identity and phosphorylation sites on the C-terminus of the purified ERα could be positively confirmed by MS using only 1 mg of cellular protein.

Recently, capturing or transforming greenhouse gases, such as CO(2) and N(2)O, have attracted considerable interest from the perspective of environmental protection. In the present work, by studying CO(2) and N(2)O adsorption on pristine and calcium (Ca)-decorated fullerenes (C(60)) with density functional theory (DFT) methods, we have evaluated the potential application of this C(60)-based complex for the capture of CO(2) and transformation of N(2)O. The results indicate that the adsorptions of CO(2) and N(2)O molecules on the pristine C(60) are considerably weak accompanied by neglectable charge transfer. When C(60) is decorated with Ca atoms, however, it is found that CO(2) and N(2)O adsorptions on the C(60) are greatly enhanced. Up to five CO(2) molecules can be adsorbed on the CaC(60) system due to the electrostatic interaction. For N(2)O molecule, it is first molecularly adsorbed on the Ca atom with the adsorption energy of -0.534 eV, followed by the N(2) formation with a low barrier and high exothermicity. Moreover, when four Ca atoms are decorated on the surface of C(60), the maximum number of the adsorbed CO(2) molecules is 16. Our results might be useful not only to widen the potential applications of fullerene but also to provide an effective method to capture or transform greenhouse gases.

Detection of carbon dioxide (CO2) is very important in environmental, biological, and industrial processes. Recent experiment showed that carbon nanotubes can act as chemical sensors for detecting certain gaseous molecules such as NH3, NO2, and O2. Unfortunately, the intrinsic stability of CO2 makes its sensing by CNTs unsuccessful due to the rather weak adsorption energy on the tube surface. In the present Article, we study the CO2 adsorption on various zigzag (n,0) (n = 6, 8, 10, 12, and 18) single-walled SiC nanotubes to explore the possibility of the SiC tube as potential gas sensors for CO2-detection by density functional theory (DFT) calculations. It is found that tube diameter and CO2 coverage play important roles in the tube-CO2 interaction. A single CO2 can be chemisorbed to the Si-C bonds of SiCNT with appreciable adsorption energy and can draw significant charge transfer from the SiCNT. The adsorption energy decreases gradually with increased tube diameter. The addition of more CO2 molecules in different patterns has been considered for the exemplified (8,0) tube, and CO2 molecules prefer to be as far from each other as possible. With the increase of CO2 coverage, the interaction between CO2 molecules and tube becomes weaker, and up to eight CO2 molecules can be adsorbed on the tube. In addition, we find that the band gap is lowered to a different degree due to the different adsorption. Because of the sufficient charge transfer and high concentration of CO2, SiCNT could be a perfect material for efficiently detecting the CO2 molecule.

Four cubane-like Cu4I4 units are assembled around an iodine atom to form the giant, mixed-valent Cu(II)Cu(I)15I17 cluster. The Cu(II)Cu(I)15I17 cluster and a bipyrazole linker form a 3D open framework with paramagnetic and thermochromic properties. This paper also touches on the resemblance of this cluster to the self-similar object of a Sierpinski tetrahedron.

Solvothermal reactions of 4-(pyrid-4'-yl)-3,5-dimethylpyrazole (HPpz) with CuBr in two mixed solvents, NH3.H2O/EtOH and NH3.H2O/MeCN, afforded respectively a copper(I) trimer, [Cu(Ppz)]3(1), and a polymer, {[Cu(Ppz)]3[CuCN] 3} (2), both containing the [Cu(Ppz)]3 entity as a building block. The products were found to be photoluminescent and, more interestingly, when cooled from room temperature to 10 K, they showed a blue shift followed by a red shift (hereafter shortened to a red-after-blue shift) of emission.