Comparison of bioactivities of 5-Fluoro, 5-Iodo, 5-Iodovinyl, and 5-fluorovinyl arabinosyl uridines against SR-39 TK-transfected murine prostate cancer cells

A cell survival assay of the four arabinosyl uridine analogs with functionalities of 5-fluoro, 5-fluorovinyl, 5-iodo, and 5-iodovinyl as potential positron-emitter tagged probe for monitoring cancer gene therapy were performed. Cytotoxicities of 5-fluoro-, 5-iodo-, 5-fluorovinyl, and 5-iodovinyl arabinosyl uridines against SR-39 thymidine kinase transfected murine prostate cancer cells have been evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. None of them showed significant bioactivity. A syn conformation derived from intra-hydrogen bonding was suggested for the unfavorable interaction and diminished bioactivity.     

Novel carbazole/fluorene hybrids: host materials for blue phosphorescent OLEDs

[reaction: see text] A series of carbazole/fluorene (CBZm-Fn) hybrids were effectively synthesized through Friedel-Crafts-type substitution of the carbazole rings. These compounds were thermally and morphologically stable host materials for OLED applications. Efficient blue phosphorescent OLEDs were obtained when employing CBZ1-F2 as the host and FIrpic as the guest.     

Redox Communication within Multinuclear Iron–Sulfur Complexes Related to Electronic Interplay in the Active Site of [FeFe]Hydrogenase

The one‐electron oxidations of a Fe₂ complex lead to the formation of a persistent metal‐stabilized thiyl radical Fe₂ species, mixed‐valent Fe₄, and Fe₈ complexes. The unpaired spin in the Fe₂ radical species delocalizes over the Fe₂ and the aromatic dithiolate, mostly on the terminal sulfur. The subsequent dimerization of the singly oxidized Fe₂ to the Fe₄ retains the partial thiyl radical character. For an analogue with less steric hindrance, the π–π stacking interaction between the dithiolato aromatic rings induces generation of the Fe₈, in which process electronic structures of the species are modulated through reducing the thiyl radical to the thiolate. Electronic reorganization repeats when the Fe₈ is converted to Fe₄. Electronic interplay in the complexes decreases the energy gap of frontier MOs and buffers electronic impacts upon redox events. Easier accessible redox potentials and increased stability of the species are facilitated. The results demonstrate that electronic versatility of the benzenedithiolate exerts pronounced influences on electronic and coordination structure of the metal complexes.     

Adsorptive stripping voltammetry of some trace elements in biological samples,II: Nickel,arsenic, aluminium and selenium

A study of the adsorptive stripping voltammetry of nickel, aluminium, selenium and arsenic is reported in which 2,5-dimercapto-1,3,4-thiadiazole (DMTD) has been used as a chelating agent. By a suitable choice of deposition potential, deposition time, reagent reaction time and other operating conditions, the determination of the four elements could be achieved.By the use of benzyltrimethyl ammonium methoxide as a digesting solvent, it was possible to apply the procedure to the direct determination of the four elements in biological samples.     

Syntheses and Crystal Structures of Bis-Citrato,Bis-Citramalato and Bis-Malato Germanate(IV) Complexes

Bis-citrato 1a-d , bis-citramalato 2 and bis-malato 3 germanate(IV) complexes were synthesized from germanium dioxide and citric acid, citramalic acid and malic acid respectively and were identified with IR, NMR and elementary analysis. Crystal 1a is triclinic, space group P1 with a = 7.919(2), b = 7.968(3), c = 9.605(3) Å, α = 94.25(3), β = 108.03(2), γ= 113.05(3)°, Z = 1, and the final residue, R(F), is 0.033 for 2583 reflections. Crystal 2 is monoclinic, space group C2 with a = 10.226(4), b = 12.802(4), c = 6.141(1) Å, β = 100.75(2)°, Z = 2, and the final residue, R(F), is 0.034 for 934 reflections. Both 1a and 2 have slightly distorted octahedral structures with citrate or citramalate ions as a tridentate ligand that forms five-, six- and seven-membered rings with the central metal. There is a two-fold axis through the central atom of compound 2 instead of the inversion center of 1a . Same structures for these six complexes are indicated because the spectral patterns of the other four compounds, 1b-d and 3 , are similar to those of compounds 1a and 2 .     

SnO2 nanosheets grown on graphene sheets with enhanced lithium storage properties

We demonstrate a new hydrothermal method to directly grow SnO(2) nanosheets on a graphene oxide support that is subsequently reduced to graphene. This unique SnO(2)/graphene hybrid structure exhibits enhanced lithium storage properties with high reversible capacities and good cycling performance.     

Instantaneous room-temperature and highly enantioselective ArTi(O-i-Pr)3 additions to aldehydes

Direct asymmetric additions of ArTi(O-i-Pr)(3) to aldehydes catalyzed by a titanium catalyst of (R)-H(8)-BINOL are reported. The reactions proceed instantaneously at room temperature, affording alcohols in ≥90% ee. Importantly, the ArTi(O-i-Pr)(3) reagent differentiates the ligand effectiveness in an order of H(8)-BINOL > BINOL > TADDOL > diol 3 > disulfonamide 2.     

Sinulochmodins A-C, three novel terpenoids from the soft coral Sinularia lochmodes

An unprecedented C,C-linked dimeric norcembranoid (sinulochmodin A, 1), a novel isocembranoid (sinulochmodin B, 2), and a novel yonarane norditerpenoid (sinulochmodin C, 3) were isolated from the soft coral Sinularia lochmodes. The structures of these metabolites were elucidated by extensive spectroscopic analysis and on the basis of the absolute structures of two related norditerpenoids (4 and 5), which were determined for the first time by a modified Mosher method. A plausible pathway for the biosynthesis of 1 and 3-5 from 2 was postulated. [structure: see text]