Poly[di(2-thiophenyl)carborane]s: conducting polymers with high electrochemical and thermal resistance.

International audienceThe synthesis, X-ray structure and electropolymerization of three new carbon-carbon linked di(2-thiophenyl)carboranes (, and ) are reported; the resulting polymers bearing icosahedral ortho-, meta- or para-carborane clusters show high thermal and electrochemical stabilities in comparison with unsubstituted polythiophene; the ortho-carborane-containing polymer has the highest conductivity of the new materials

Syntheses and cellular investigations of di-aspartate and aspartate-lysine chlorin e\u3csub\u3e6\u3c/sub\u3e conjugates

© The Royal Society of Chemistry 2016. Chlorin e6 is a tricarboxylic acid degradation product of chlorophyll a. Four chlorin e6 bis(amino acid) conjugates were regioselectively synthesized bearing two aspartate conjugates in the 131,173- and 152,173-positions, or at the 131,152via an ethylene diamine linker. One additional conjugate bearing two different amino acids, lysine at 131via an ethylene diamine linker and an aspartate at 152via a β-alanine linker was also synthesized. The cytotoxicity and uptake of four di(amino acid) chlorin e6 conjugates were investigated in human HEp2 cells, and compared with chlorin e6. The most cytotoxic and most taken up conjugates were the zwitterionic 131,152-disubstituted conjugates 28 and 33; these also localized in multiple organelles. In contrast, the anionic 131,173- and 152,173-di-aspartyl chlorin e6 conjugates 12 and 13 showed low dark cytoxicity and lower phototoxicity compared with chlorin e6

Bilitrienones from the chemical oxidation of dodecasubstituted porphyrins

The structure of the ring-opened product from direct oxidation of meso-tetra-arylporphyrins has been controversial for three decades. Herein we show that bilitrienones 2 are obtained from oxidation of metal-free dodecasubstituted porphyrins 1 in the presence of sodium nitrite, trifluoroacetic acid, and air oxygen. The presence of the para-nonyl groups in 1b stabilized the corresponding bilitrienone 2b, which was characterized by X-ray crystallography. In the absence of the para-nonyl groups bilitrienone 2a undergoes a rapid hydration reaction, giving biladienone 3a as the major isolated product. The molecular structures of 2b and 3a, and the photochemical isomerization of 3a are discussed. © 2009 Elsevier Ltd

4-Anilino-1-benzyl­piperidine-4-carbo­nitrile

The title mol­ecule, C19H21N3, an important precursor in the synthesis of porphyrin–fentanyl conjugates, has its piperidine ring in the chair conformation, with endocyclic torsion-angle magnitudes in the range 53.26 (8)–60.63 (9)°. The C N group is axial, while the CH2Ph and NHPh groups are equatorial. The NH group does not engage in strong hydrogen bonding, but forms an inter­molecular N—H⋯N inter­action

Characterization of designed cobaltacarborane porphyrins using conductive probe atomic force microscopy

© 2016 Jayne C. Garno, et al. Porphyrins and metalloporphyrins have unique chemical and electronic properties and thus provide useful model structures for studies of nanoscale electronic properties. The rigid planar structures and π-conjugated backbones of porphyrins convey robust electrical characteristics. For our investigations, cobaltacarborane porphyrins were synthesized using a ring-opening zwitterionic reaction to produce isomers with selected arrangements of carborane clusters on each macrocycle. Experiments were designed to investigate how the molecular structure influences the selforganization, surface assembly, and conductive properties of three molecular structures with 2, 4, or 8 cobaltacarborane substituents. Current versus voltage (I-V) spectra for designed cobaltacarborane porphyrins deposited on conductive gold substrates were acquired using conductive probe atomic force microscopy (CP-AFM). Characterizations with CP-AFM provide capabilities for obtaining physical measurements and structural information with unprecedented sensitivity. We found that the morphology of cobaltacarborane porphyrin structures formed on surfaces depends on a complex interplay of factors such as the solvent used for dissolution, the nature of the substrate, and the design of the parent molecule. The conductive properties of cobaltacarborane porphyrins were observed to change according to the arrangement of cobaltacarborane substituents. Specifically, the number and placement of the cobaltacarborane ligands on the porphyrin macrocycle affect the interactions that drive porphyrin self-assembly and crystallization. Interestingly, coulombic staircase I-V profiles were detected for a porphyrin with two cobaltacarborane substituents

Oscillatory and alternate flows in a microfluidic device

The mixing properties of systems with oscillatory or alternate flows are studied by numerical methods. Preliminary results show that, for alternate flows, the contact area between high and low concentration regions increases and mixing is achieved from the combination of transversal diffusion and axial advection. The improvement in the mixing process shows that this method is very useful for designing mixers in lab-on-a-chip devices.R&D Centre Algoritmi - University of Minho Engineering School (program IN2TEC) - University of Minho

Numerical study of micromixing combining alternate flow and obstacles

Mixing in microsystems, combining alternate flow with obstacles, is studied by numerical methods. Simulations show that the layers of high and low solute concentrations, created by the alternate flow, are split into smaller chunks of fluid by obstacles inserted in the mixing channel, decreasing the critical mixing length. Reverse flow is necessary to guarantee symmetry and good mixing. Mixing increases with the increase of the number of obstacles. Increase of frequency improves mixing but requires an increase of reverse flow. The improvement in the mixing process shows that this method is very useful for designing mixers for lab-on-a-chip devices.Support for this research was provided by the Engineering School of University of Minho (program IN2TEC) and the Portuguese Science Foundation (grant FTDC/B10/70017/2006 and grant SFRH/BPD/17689/2004)

Bis(1-tosyl-2-pyrrol­yl)ethyne

The title mol­ecule, C24H20N2O4S2, has crystallographic inversion symmetry with a triple-bond distance of 1.206 (2) Å. The alkyne is not quite linear, with a C—C C angle of 175.78 (16)°. The planar pyrrole rings are parallel but offset from coplanarity by 0.318 (1) Å. The conformation of the sulfonyl group with respect to the pyrrole ring is such that an O atom is nearly eclipsed with this ring, having an O—S—N—C torsion angle of 3.48 (11)°. C—H⋯O inter­actions [C⋯O 3.278 (2) Å, 136° about H] between pyrrole H and sulfonyl O atoms lead to the formation of ladder-like chains

Dibenzyl 3,3′,4,4′-tetra­methyl-5,5′-(ethynedi­yl)bis­(pyrrole-2-carboxyl­ate)

The title mol­ecule, C30H28N2O4, has crystallographic twofold rotation symmetry, with the pyrrole planes forming a dihedral angle of 40.49 (4)°. The pyrrole N—H donor and adjacent ester carbonyl acceptor form R 2 2(10) hydrogen-bonded rings about inversion centers, leading to chains of hydrogen-bonded mol­ecules along [001]