Triphenylsulfonium topophotochemistry.

The products from the 193 nm irradiation of triphenylsulfonium nonaflate (TPS) embedded in a poly(methyl methacrylate) (PMMA) film have been characterized. The analysis of the photoproduct formation was performed using chromatographic techniques including HPLC, GPC and GC-MS as well as UV-vis and NMR spectroscopic methods. Two previously unreported TPS photoproducts, triphenylene and dibenzothiophene, were detected; additionally, GPC and DOSY-NMR spectroscopic analyses after irradiation suggested that TPS fragments had been incorporated into the polymer film. The irradiation of acetonitrile solutions containing 10% w/v PMMA and 1% w/v TPS in a 1 cm-path-length cuvette showed only a trace amount of triphenylene or dibenzothiophene, indicating that topochemical factors were important for the formation of these molecules. The accumulated evidence indicates that both products were formed by in-cage, secondary photochemical reactions: 2-(phenylthio)biphenyl to triphenylene, and diphenylsulfide to dibenzothiophene.

Polymer coordination promotes selective CO2 reduction by cobalt phthalocyanine.

Cobalt phthalocyanine (CoPc) is a known electrocatalyst for the carbon dioxide reduction reaction (CO2RR) that, when adsorbed onto edge-plane graphite (EPG) electrodes, shows modest activity and selectivity for CO production along with co-generation of H2. In contrast, electrodes modified with CoPc immobilized in a poly-4-vinylpridine (P4VP) film show dramatically enhanced activity and selectivity compared to those modified with CoPc alone. CoPc-P4VP films display a faradaic efficiency of ∼90% for CO, with a turnover frequency of 4.8 s-1 at just -0.75 V vs. RHE. Two properties of P4VP contribute to enhancing the activity of CoPc: (1) the ability of individual pyridine residues to coordinate to CoPc and (2) the high concentration of uncoordinated pyridine residues throughout the film which may enhance the catalytic activity of CoPc through secondary and other outer coordination sphere effects. Electrodes modified with polymer-free, five-coordinate CoPc(py) films (py = pyridine) and with CoPc catalysts immobilized in non-coordinating poly-2-vinylpyridine films were prepared to independently investigate the role that each property plays in enhancing CO2RR performance of CoPc-P4VP. These studies show that a synergistic relationship between the primary and outer coordination sphere effects is responsible for the enhanced catalytic activity of CoPc when embedded in the P4VP membrane.

Fetal urogenital sinus with consecutive hydrometrocolpos because of labial fusion: prenatal diagnostic difficulties and postpartal therapeutic management.

OBJECTIVE: To elucidate the differential diagnoses of tumorous dilations in the fetal pelvic region detected by prenatal ultrasound and the postnatal management demonstrated on a fetus with 29 weeks of gestation with a retrovesical located bottle-like cystic structure measuring 54 x 31 x 27 mm within the pelvis. Postnatal findings were a labial fusion and a consecutive hydrometrocolpos due to a urethrovaginal fistula. METHOD: Case report of a fetus affected by an intricate cloacal anomaly. RESULTS: The long-term prognosis for this nonsyndromic form of hydrometrocolpos without any other structural defects or organic failures after operative sanitation is excellent. Final reconstruction is planned at about 12 months of age. CONCLUSION: Prenatal diagnosis of tumorous dilations in the fetal pelvic region often involves difficulties because of numerous differential diagnoses and possible presentation in late pregnancy. Magnetic resonance imaging could be a useful complementary tool for assessing these anomalies when ultrasonography is inconclusive. In some cases, the final diagnosis cannot be confirmed until after delivery.