A self-assembled, metallo-organic supramolecular frequency doubler.

The dimeric self-assembly program of a new, multidentate ligand with cuprous ions overcomes crystal packing forces, which leads to C(i) symmetry in the solid state, to form a no less than partially C(2)-symmetric structure in solution. The resulting tetranitro-substituted dicopper(i) metallocyclophane displays an exceptionally strong second harmonic frequency response (ß = (3000 ± 600) × 10(-30) esu for a fundamental at 800 nm).

Synthesis of hydrophobic derivatives of the G/\C base for rosette nanotube self-assembly in apolar media.

Eleven self-complementary G/\C derivatives bearing hydrophobic moieties were synthesized and characterized. One representative derivative from this family was shown to self-assemble into rosette nanotubes in hexane and form Langmuir-Blodgett films at the air-water interface.

Synthesis and stereochemistry of long-chain quinoxaline metallocyclophanes.

Condensation of 1,2-diamino-4,5-bis(n-alkoxy)arenes with an oligopyridyl-type alpha-diketone afforded a series of long-chain pyridine-quinoxaline hybrids. These were evaluated for their ability to self-assemble with tetrahedral Cu(I) and Ag(I) to form dimeric, double-decker amphiphillic complexes having a flattened metallocyclophane topology. Detailed NOESY and T1 relaxation time experimentation showed that the configuration of the dicopper(I) complexes corresponds to inversion (meso) symmetry, which leads to an extended molecular shape, wherein the alkoxy chains of the individual ligand components lie on opposite sides of the metallocyclophane core, as opposed to the same side. Preliminary measurements show that the disilver(I) complexes having nC12H25 and nC18H37 chains exhibit reversible melting processes and undergo two endothermic transitions each, at 189/237 and 59/80 degrees C, respectively.

Formation of a solubilized cobalt block oligomer from a M2L-type double helicate.

The multi-dentate ligand, 2,3,5,6-tetrakis(2,2'-bipyridyl)pyrazine (L) and divalent cobalt self-assemble to a block co-polymer-like oligomer in solution, which contains at least the L(7)Co(8) fragment. The extent of oligomerization is sensitive to the water content in acetonitrile solution. In the solid state, the simple monomer [LCo(2)(CH(3)CN)(4)][ClO(4)](4) is isolated. The X-ray structure of the crystallized material (containing four CH(3)CN solvate molecules) reveals a double-helical complex with two heptadentate Co(II) sites, and a helical pitch of approximately 28.1 A. Coupled Co(I/II) redox processes are observed between the two metal centres.

Optimization of amide-based inhibitors of soluble epoxide hydrolase with improved water solubility.

Soluble epoxide hydrolase (sEH) plays an important role in the metabolism of endogenous chemical mediators involved in the regulation of blood pressure and inflammation. 1,3-Disubstituted ureas with a polar group located on the fifth atom from the carbonyl group of urea function are active inhibitors of sEH both in vitro and in vivo. However, their limited solubility in water and relatively high melting point lead to difficulties in formulating the compounds and poor in vivo efficacy. To improve these physical properties, the effect of structural modification of the urea pharmacophore on the inhibition potencies, water solubilities, octanol/water partition coefficients (log P), and melting points of a series of compounds was evaluated. For murine sEH, no loss of inhibition potency was observed when the urea pharmacophore was modified to an amide function, while for human sEH 2.5-fold decreased inhibition was obtained in the amide compounds. In addition, a NH group on the right side of carbonyl group of the amide pharmacophore substituted with an adamantyl group (such as compound 14) and a methylene carbon present between the adamantyl and amide groups were essential to produce potent inhibition of sEH. The resulting amide inhibitors have 10-30-fold better solubility and lower melting point than the corresponding urea compounds. These findings will facilitate synthesis of sEH inhibitors that are easier to formulate and more bioavailable.