"Nindigo": synthesis, coordination chemistry, and properties of indigo diimines as a new class of functional bridging ligands.

Reactions of indigo with anilines provide a simple route to indigo N,N'-diaryldiimines ("Nindigo"), a new binucleating ligand with two beta-diketiminate-type metal binding sites. Bis-palladium complexes have interesting ligand-centred properties such as redox activity and intense near infrared absorption.

Interdisciplinary treatment of an end-to-end occlusion due to congenitally missing maxillary lateral incisors.

Odontogenic aplasia, or the congenital absence of permanent teeth, is relatively common. When the missing teeth include the maxillary lateral incisors, treatment considerations must reconcile both esthetic and functional objectives. In developing dentition, erupting adjacent teeth can drift from their intended positions into the edentulous space created by the congenitally missing tooth.

Synthesis and biological evaluation of novel pyrazole compounds.

A novel dipyrazole ethandiamide compound and acid chloride of pyrazolo[3,4-d]pyrimidine 4(5H)-one were prepared and reacted with a number of nucleophiles. The resultant novel compounds were tested in several in vitro and in vivo assays. Three compounds inhibited the secretion of neurotoxins by human THP-1 monocytic cells at concentrations that were not toxic to these cells.

Ansellone A, a sesterterpenoid isolated from the nudibranch Cadlina luteromarginata and the sponge Phorbas sp., activates the cAMP signaling pathway.

Ansellone A (1) has been isolated from the dorid nudibranch Cadlina luteomarginata and the sponge Phorbas sp. It has the new "ansellane" sesterterpenoid carbon skeleton, and it activates the cAMP signaling pathway.

Synthesis and structural studies of chiral indium(III) complexes supported by tridentate diaminophenol ligands.

Indium(III) dimethyl, dihalide, and alkoxy-bridged complexes bearing a chiral diaminophenoxy tridentate ligand [NN(H)O](-) were synthesized. The dimethyl complex (NN(H)O)InMe(2) (1) was unreactive toward ethanol and 2-propanol and only partially reactive toward the more acidic phenol. The dihalide complexes (NN(H)O)InX(2) (X = Cl (3), Br (4), I (5)) reacted with NaOEt to form robust alkoxy-bridged complexes with the formula {[(NN(H)O)InX](2)(mu-X)(mu-OEt)} (X = Cl (6), Br (7), I (8)).

Controlled radical polymerisation of methyl acrylate initiated by a well-defined cobalt alkyl complex.

Cobalt-mediated radical polymerisation of methyl acrylate is effected at moderate temperature by both a square planar bis(beta-ketoaminato)cobalt(II) complex in the presence of V-70 diazo radical initiator, and by a well-defined cobalt(III) alkyl derivative in the absence of a diazo complex. Polymerisation rates suggest that both reversible termination and degenerative transfer mechanisms are operative.

Synthesis and characterisation of bis(beta-ketoaminato) complexes of cobalt(II).

Condensation of 1-phenyl-1,3-butanedione with various substituted anilines affords N-aryl substituted beta-ketoamines PhC(O)CHC(CH(3))Naryl, which, when deprotonated and reacted with Co(OAc)(2).4H(2)O yields a series of bis(beta-ketoaminato)cobalt(II) complexes 1b to 6b (aryl = Ph, 1b; p-CH(3)C(6)H(4), 2b; 2,6-(CH(3))(2)C(6)H(3), 3b; 3,5-(CH(3))(2)C(6)H(3), 4b; p-CF(3)C(6)H(4), 5b; p-CH(3)OC(6)H(4), 6b). All six cobalt compounds were characterised by (1)H NMR, elemental analysis, magnetic susceptibility, and X-ray crystallography, indicating a uniform tetrahedral geometry in all cases.

Reactions of a phosphinoaldehyde with Pd(II), Rh(I), and Ir(I) precursors, including the formation of complexes containing a P,OH-chelated phosphinohemiacetal ligand: a new bonding mode.

The complexes trans-PdCl(2)[eta(1)-P-(Ph(2)P)CH(Ph)CH(Me)CH(OMe)(2)](2) (1) and M(H)Cl[eta(2)-P,OH-(Ph(2)P)CH(Ph)CH(Me)CH(OH)OMe][eta(2)-P,C(O)-(Ph(2)P)CH(Ph)CH(Me)C(O)], M = Rh (3) and Ir (4), are synthesized by reacting the phosphinoaldehyde [3-(diphenylphosphino)-3-phenyl-2-methyl]propionaldehyde [(Ph(2)P)(2)CH(Ph)CH(Me)CHO] with trans-PdCl(2)(PhCN)(2), [RhCl(COD)](2), and [IrCl(COD)](2), respectively, in MeOH; trans-PdCl(2)[eta(1)-P-(Ph(2)P)CH(Ph)CH(Me)CHO](2) (2) is isolated from the same reaction in CH(2)Cl(2). One diastereomer of each of the complexes 1, 3 x MeOH, and 4 x MeOH was characterized by X-ray analysis. The stereochemistry of such complexes in the solid state and in solution (MeOH and CH(2)Cl(2)) is discussed.

In vitro studies of 3-hydroxy-4-pyridinones and their glycosylated derivatives as potential agents for Alzheimer's disease.

Glycosides of 3-hydroxy-4-pyridinones were synthesized and characterized by mass spectrometry, elemental analysis, (1)H and (13)C NMR spectroscopy, and in one case by X-ray crystallography. The Cu(2+) complex of a novel 3-hydroxy-4-pyridinone was synthesized and characterized by IR and X-ray crystallography, showing the ability of these compounds to chelate potentially toxic metal ions. An MTT cytotoxicity assay of a selected glycosylated compound showed a relatively low toxicity of IC(50) = 570 +/- 90 microM in a human breast cancer cell line.

Verdazyl radicals as redox-active, non-innocent, ligands: contrasting electronic structures as a function of electron-poor and electron-rich ruthenium bis(beta-diketonate) co-ligands.

Spectroscopic, structural, and computational studies of verdazyl radical-ruthenium complexes reveal the verdazyl to be a redox-active and non-innocent ligand. The ensuing delocalization of charge is highly sensitive to the nature of the beta-diketonate co-ligands.

Bafilomycins produced in culture by Streptomyces spp. isolated from marine habitats are potent inhibitors of autophagy.

Five new bafilomycins, F (1) to J (5), have been isolated from laboratory cultures of two Streptomyces spp. obtained from marine sediments collected in British Columbia, and their structures have been elucidated by detailed analysis of spectroscopic data and the synthesis of model compounds. The new bafilomycins F (1), G (2), H (3), and J (5) along with several co-occurring known analogues showed potent inhibition of autophagy in microscopy and biochemical assays.

Conjugated ligand-based tribochromic luminescence.

A Au(I) complex containing a terthienyl diphosphine ligand is non-emissive in the crystalline form, but exhibits intense ligand-based emission upon grinding attributed to increased planarization in the terthienyl ligand.

Electron rich bidentate phosphinimine-imine ligands: synthesis and reactivity of late transition metal complexes.

Electron rich phosphinimine-imine proligands Ph(3)PN(C(6)H(4))C(Ph)(NAr) (L(Ar)) (Ar = 4-(OEt)C(6)H(4) (OEt), 3,5-Me(2)C(6)H(3)(Xyl)) were synthesized in three steps from 2-aminobenzophenone. These compounds, along with previously reported L(Mes) and L(Tol) (Mes = 2,4,6-Me(3)C(6)H(2), Tol = 4-MeC(6)H(4)) were used to synthesize a series of tetracarbonyltungsten(0) complexes: L(Mes)W(CO)(4) (1), L(Tol)W(CO)(4) (2), L(OEt)W(CO)(4) (3), and L(Xyl)W(CO)(4) (4). The ligands were evaluated by analysis of the carbonyl stretching frequencies of the tungsten complexes and were shown to be better sigma-donors and poorer pi-acceptors compared to similar ligands in the literature.

Ethylene modifies architecture of root system in response to stomatal opening and water allocation changes between root and shoot.

Ethylene plays a key role in the elongation of exploratory and root hair systems in plants, as demonstrated by pharmacological modulation of the activity of ethylene biosynthesis enzymes: ACC synthase (ACS) and ACC oxidase (ACO). Thus, treatments with high concentrations (10 microM) of aminoethoxyvinylglycine (AVG, inhibitor of ACS) and 1-aminocyclopropane carboxylic acid (ACC, ethylene precursor, ACO activator) severely decrease the elongation of the exploratory root system but induce opposite effects on the root hair system: root hair length and numbers were increased in seedlings treated with ACC, whereas they were reduced in seedlings treated with AVG. Until now, such elongation changes of root architecture had not been questioned in terms of nitrate uptake.

Enamides and enesulfonamides as nucleophiles: formation of complex ring systems through a platinum(II)-catalyzed addition/Friedel-Crafts pathway.

Cyclic enamine derivatives (enesulfonamides and enamides) tethered to an 1-arylalkynyl fragment undergo a platinum(II)-catalyzed tandem alkyne addition/Friedel-Crafts ring closure to form nitrogen-containing polycyclic structures. Regioselectivity in the initial addition of the enesulfonamide or enamide nucleophile to the platinum(II)-alkyne complex is important. Electron-rich arenes and heterocycles led to the formation of products resulting from an initial 6-endo cyclization.

Noninnocent behavior of ancillary ligands: apparent trans coupling of a saturated N-heterocyclic carbene unit with an ethyl ligand mediated by nickel.

Oxidative addition of the tridentate N-heterocyclic carbene (NHC) diphosphine ligand precursor ([PCP]H)PF(6) (1) {[PCP] = o-(i)Pr(2)PC(6)H(4)(NC(3)H(4)N)o-C(6)H(4)P(i)Pr(2)} to Ni(COD)(2) results in the formation of the nickel(II) hydride complex ([PCP]NiH)PF(6) (2). This hydride undergoes a rapid reaction with ethylene to generate a nickel(0) complex in which an ethyl group has been transferred to the carbene carbon of the original NHC-diphosphine ligand. If the first intermediate is the anticipated square-planar nickel(II) ethyl species, then the formation of the product would require a process that involves a trans C-C coupling of the NHC carbon and a presumed Ni-ethyl intermediate.

Near-Infrared absorbing azo dyes: synthesis and x-ray crystallographic and spectral characterization of monoazopyrroles, bisazopyrroles, and a boron-azopyrrole complex.

Symmetric 2,5-bisazopyrroles 2(a-d) were synthesized by a one-step reaction of substituted phenyl diazonium salts [R'(Ph)N2(+)Cl-] [a, R' = 4-N(CH3)2; b, R' = 2-OH; c, R' = 2-CO2H; d, R' = 4-NO2] with pyrrole under basic conditions. Asymmetric 2,5-bisazopyrroles 3(a-d) were synthesized by reacting substituted phenyl diazonium salts [R''(Ph)N2(+)Cl-] (a, R'' = 4-OCH(3); b, R'' = H; c, R'' = 4-Br; d, R'' = 4-NO2) with 2-(4-dimethylaminophenylazo)-1H-pyrrole (1a) under the same conditions. The reactions of 2a with boron trifluoride and iodomethane provided a BF2-azopyrrole complex of 1H-pyrrolo[2,1-c]-1,2,4,5-boratriazole (4) and 2,5-bisazo-1-methylpyrrole 5.

Self-assembly of oligomeric linear dipyrromethene metal complexes.

BF(2) capped dipyrrin dimers were synthesized and have been used to terminate oligomerization to form a series of controlled length oligomers; the crystal structures of the metal complexes were investigated and correlations between the structures and optical properties were established.

Conjugated thiophene-containing oligoacenes through photocyclization: bent acenedithiophenes and a thiahelicene.

The preparation of bent anthradithiophenes (BADTs) using an oxidative photocyclization-based synthetic strategy is reported. The optical properties of the new compounds were characterized by UV-vis and fluorescence spectroscopies, and the redox properties were probed by cyclic voltammetry. Structural studies using single crystal X-ray crystallography show that the unsubstituted BADT adopts a slipped cofacial stacking arrangement in the solid state with pi-pi interactions along the intermolecular stacking axis.

Facile synthesis of dicyanovinyl-di(meso-aryl)dipyrromethenes via a dipyrromethene-DDQ adduct.

The dicyano-substituted vinyl dipyrromethene and compound are near-planar and were prepared from a simple meso-aryl dipyrromethane via the DDQ adduct ; the unique structures of , and were confirmed by X-ray diffraction analysis.

Oxidized forms of a tripyrrane: alpha-tripyrrinone, beta-tripyrrinone and a C2 symmetric hexapyrrole.

alpha- and beta-tripyrrinone isomers (), and a C(2) symmetric hexapyrrole () were isolated from the oxidation of meso-perfluorophenyl tripyrrane (and meso-2,6-dichlorophenyl tripyrrane ) with DDQ under aerobic conditions, and the structure of was determined by X-ray crystallographic analysis.

Design, synthesis, and imaging of small amphiphilic rhenium and (99m)technetium tricarbonyl complexes.

The design, synthesis, radiolabeling, evaluation of stability, and in vivo investigation are presented of three variably charged, novel, short C(8) chain derivatized chelators for the [M(CO)(3)](+) core (M = (99m)Tc or Re). Labeling with [(99m)Tc(CO)(3)](+) showed complex formation in under 1 h reaction time and high stability toward 24 h histidine and cysteine challenges, as well as distinctive log P values for each complex. Distinct localization of small amphiphilic molecules in in vivo systems depends on the charge of the polar moiety and was studied via biodistribution (4 h) and imaging (15 min, 1, 2, and 4 h) in female C57Bl/6 mice.

Synthetic approaches to the microtubule-stabilizing sponge alkaloid ceratamine A and desbromo analogues.

Two synthetic approaches to the microtubule-stabilizing ceratamine alkaloids are described. The first approach involved attempts to graft an aminoimidazole moiety onto an azepine ring to form partially hydrogenated versions of the unprecedented aromatic imidazo[4,5-d]azepine core of the ceratamines. This route ultimately failed because it was not possible to aromatize the partially hydrogenated ceratamine intermediates.

5-(2,6-Dimethoxy-phen-oxy)-2-methyl-sulfanylmethyl-2H-tetra-zole.

In the title mol-ecule, C(11)H(14)N(4)O(3)S, the tetra-zole and benzene rings are nearly perpendicular to each other, forming a dihedral angle of 104.93 (14)°. The crystal packing exhibits weak inter-molecular C-H⋯O hydrogen bonds.