Color detection using chromophore-nanotube hybrid devices.

We present a nanoscale color detector based on a single-walled carbon nanotube functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrate the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggest that upon photoabsorption, the chromophores isomerize from the ground state trans configuration to the excited state cis configuration, accompanied by a large change in dipole moment, changing the electrostatic environment of the nanotube.

(E)-4-[(4-Nitro-phen-yl)diazen-yl]phenyl anthracene-9-carboxyl-ate.

In the title compound, C(27)H(17)N(3)O(4), the azo group displays a trans conformation and the dihedral angles between the central benzene ring and the pendant anthracene and nitro-benzene rings are 82.94 (7) and 7.30 (9)°, respectively.

(E)-2-{Eth-yl[4-(4-nitro-phenyl-diazen-yl)phen-yl]amino}ethyl anthracene-9-carboxyl-ate.

The crystal structure of the title compound, C(31)H(26)N(4)O(4), displays a trans conformation for the nitro-phenyl-diazenyl portion of the mol-ecule. Packing diagrams indicate that weak C-H⋯O hydrogen bonds, likely associated with a strong dipole moment present in the mol-ecule, dictate the arrangement of mol-ecules in the crystal structure.

Metathesis depolymerization for removable surfactant templates.

Current methodologies for the production of meso- and nanoporous materials include the use of a surfactant to produce a self-assembled template around which the material is formed. However, post-production surfactant removal often requires centrifugation, calcination, and/or solvent washing which can damage the initially formed material architecture(s). Surfactants that can be disassembled into easily removable fragments following material preparation would minimize processing damage to the material structure, facilitating formation of templated hybrid architectures.

Thermally cleavable surfactants based on furan-maleimide Diels-Alder adducts.

Two new surfactant molecules are reported that contain thermally labile Diels-Alder adducts connecting the hydrophilic and hydrophobic sections of each molecule. The two surfactants possess identical hydrophobic dodecyl tail segments but have phenol and carboxylic acid hydrophilic headgroups, respectively. Deprotonation with potassium hydroxide affords the formation of water-soluble surfactants.