Intermolecular Zirconium-Catalyzed Hydrophosphination of Alkenes and Dienes with Primary Phosphines

Catalytic hydrophosphination of terminal alkenes and dienes with primary phosphines (RPH₂; R = Cy, Ph) under mild conditions has been demonstrated using a zirconium complex, [κ⁵-<i>N</i>,<i>N</i>,<i>N</i>,<i>N</i>,<i>C</i>-(Me₃SiN­CH₂CH₂)₂­NCH₂CH₂­NSiMe₂­CH]Zr (<b>1</b>). Exclusively anti-Markovnikov functionalized products were observed, and the catalysis is selective for either the secondary or tertiary phosphine (i.e., double hydrophosphination) products, depending on reaction conditions. The utility of the secondary phosphine products as substrates for further elaboration was demonstrated with a platinum-catalyzed asymmetric alkylation reaction

Fission-Track Thermochronology Applied to the Evolution of Passive Continental Margins

International audiencePassive continental margins (PCMs) form at divergent plate boundaries in response to continental breakup and subsequent formation of new oceanic basins. The onshore topography of PCMs is a key component to understand the evolution of extensional settings. The classic nomenclature of PCMs is derived from early investigations that suggested apparent tectonic stability after the initial phase of rifting and breakup. However, geological and geomorphic diversity of PCMs requires more complex models of rift and post-rift evolution. Fission-track (FT) thermochronology provides appropriate tools to decipher the long-term development of PCM topography and better resolve the spatial and temporal relationships between continental erosion and sediment accumulation in adjacent offshore basins. FT datasets have revealed complex spatial and temporal denudation histories across some PCMs and have shown that several kilometres of material may be removed from the onshore margin following rifting. Combining these data with geological and geomorphological observations, and with predictions from numerical modelling, suggests that PCMs may have experienced significant post-rift activity. Case histories illustrated in this chapter include the PCM of southeastern Africa and the conjugate PCMs of the North and South Atlantic