ABSTRACT The reaction of 6-(1H-3,5-dimethylpyrazolyl)pyridazine-3-carboxylic acid with oxalyl chloride and then 2,4-dimethyl-3-ethylpyrrole leads to [6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazin-3-yl](4-ethyl-3,5-dimethyl-1H-pyrrol-2-yl)methanone (ppyEt). The reaction of ppyEt with bromotricarbonyl(tetrahydrofuran)-rhenium(I) dimer leads to [(ppyEt)Re(CO)3Br] compound. The molecule of [(ppyEt)Re(CO)3Br]displaysa non-regular octahedron around the rhenium(I) center with a bromide. The molecule defines an intramolecular hydrogen bond between the 4-ethyl-3,5-dimethyl-1H-pyrrol-2-yl hydrogen atom and one nitrogen from the pyridazin-3-yl fragment with D⋯A 2.833(17) Å. The coplanarity of the 4-ethyl-3,5-dimethyl-1H-pyrrol-2-yl-carbonyl is attributed to this intramolecular bond, in addition to C—H⋯O≡C and N—H⋯O≡C interactions as suggested by NCI calculations.

Glycolipids are biomolecules composed of a lipid chain (lipophilic) and a monosaccharide or oligosaccharide as hydrophilic group. Their chemical structure and biological role make them undoubtedly good candidates for a large and continuously growing number of biotechnological applications. Mannose is a carbohydrate present on membrane glycolipids of a wide number of pathogenic microorganisms (bacteria, fungi, protozoa, and viruses) and specifically recognized by several lectins. We synthesized a mannose derivative linked through a short methylene chain to a pyrene moiety which behaves as a surfactant, able to aggregate, and retains the photophysical properties of pyrene: showing comparable absorption and emission spectra, having lower fluorescence quantum yield and the ability to form excimer, and finally the ability to produce O2(1Δg) with high quantum yields. Thus, this novel molecule would open future applications for detection (fluorescence) or inactivation (singlet oxygen) of bacterial pathogens, viruses, tumor cells, or particular cells.

The photochemical behavior of nimodipine (NIMO) and felodipine (FELO), photolabile drugs widely used as antihypertensive calcium channel blockers, is studied in constrained media. Specifically, we are interested in the kinetic analysis of 4-aryl-1,4-dihydropyridine photodegradation processes when they are incorporated in biological-mimicking systems like micelles or liposomes. In order to establish if the nature of the head of surfactant (ionic or nonionic) could be important modulating the photo-reactivity of these drugs, we studied the photodegradation of NIMO and FELO incorporated in micelles formed with sodium dodecyl sulfate (SDS, anionic), dodecyl-pyridinium chloride (DPC, cationic) and mono lauryl sucrose ester (MLS, nonionic) as surfactants. Additionally, the results of the photodegradation of these compounds in liposomes were also included. The results clearly indicate that both dihydropyridines studied, NIMO and FELO, are located near to the interface, but the surface charge of micelles does not affect neither, the photodegradation rate constant nor the photodegradation products profile. The absence of singlet oxygen generation in micellar media is consistent with the proposition of these 4-aryl-1,4-dihidropyridines located near to the interface of the micelle, where a polar environment is sensed. In addition, the ethanol preferential location on membranes and dihydropyridine enhanced photodegradation by alcohol presence are interesting results to consider in future research.

We have prepared a new monometallic rhenium(I) carbonyl, the complex [P,N-{(C6H5)2(C5H5N)P}Re(CO)3Br] by direct reaction of (Re(CO)3Br(THF))2 and the ligand (C6H5)2(C5H5N)P The structure in the complex shows the pyridinic-phosphine ligand in a chelating mode, occupying cis positions around the rhenium octahedral environment. The molecule displays an absorption band centered at 315 nm which has been assigned to a MLCT transition, and a luminescence quantum yield of 0.001.