Regio- and stereoselective photoallylation of electron-deficient alkenes by use of allylic silanes via photoinduced electron transfer has been described. Similar photoinduced functionalization reactions such as arylmethylation, alkylation, and silylation can be achieved by using a variety of organosilicon compounds. These photoreactions proceed via radical cations of organosilicon compounds and radical anions of electron-deficient alkenes as reactive intermediates. The key step of the photoreactions is the attack of carbon radicals, which are generated from the radical cations of organosilicon compounds, on the radical anions of alkenes. The mechanism of the regio- and stereoselective photofunctionalization is discussed.
Mössbauer spectroscopy of 129I and 197Au nuclei has been applied for AuI and AgAuI2 to clarify the electronic structures of the gold and iodine atoms, and to investigate the nature of the Au-I bonds. In the 129I Mössbauer spectra the sign of e2qQ is positive for AuI, whereas the sign is negative for AgAuI2. This is attributable to the difference in molecular structures: The iodine atom in AuI is bridged by two gold atoms and in AgAuI2 the iodine is terminal. The 197Au Mössbauer spectra suggest that the Au-I bond in AgAuI2 is more covalent than that in AuI. We have revealed that AgAuI2 consists of Ag+ and linear [I-Au-I]- units from the Rietveld refinement of the X-ray powder diffraction pattern
Aims: This study examined whether analysis of fetal behavioral states by monitoring fetal heart rate and movement using an actocardiogram (ACG), could provide prognostic information related to fetal central nervous system (CNS) lesions.
Methods: The ACG simultaneously records fetal heart rate (FHR) and fetal movement bursts composed of spikes of ultrasonic Doppler signals. Durations of FHR accelerations and fetal movement bursts were measured manually. Five actocardiographic indices were studied in 12 fetuses with CNS lesions and in 14 normal pregnancies of 28–38 weeks.
Results: Severity of the fetal CNS lesions was estimated from the acceleration/burst (A/B) duration ratio, which correlated with the rank of the sonographic fetal functional test in cases with CNS lesions. Severity of a fetal lesion may also be estimated by the regression equation of the A/B duration ratio and behavioral ranking.
Conclusion: The severity of fetal CNS lesions may be estimated by quantitative analysis of ACG usings the measurement of A/B duration ratio to provide a prognosis. An ACG may demonstrate a loss of CNS control in cases with severe brain damage.