Thermodynamically controlled platinum(II) spherical complexes were synthesized via temporary labilization of inert Pt(II)-pyridine bonds by the addition of the strong hydrogen-bond donor 2,2,2-trifluoroethanol (TFE), which weakens the pyridine-metal interaction. The platinum complex was stably trapped after removal of TFE and showed higher acid durability than its palladium counterpart.

On the western part of the Paci¢c Plate most seamounts formed during the Cretaceous period in the so -called West Paci¢c Seamount Province (WPSP). On the northwestern part of the same plate, the Joban and Japanese Seamount Trail (JJST) are also composed of Early Cretaceous seamounts. However, two new groups of knolls were recently discovered during multibeam surveys on the Paci¢c Plate along the Japan Trench. One group consists of circular knolls that are £at-topped in shape and correspond to eruptive ages of approximately 75 Ma.The other group consists of irregularly shaped knolls, also called petit-spot volcanoes, that are found on the outer-rise systems of the subducting Paci¢c Plate.These petit-spots seem much younger and available age data suggest that they only formed in the last few million years. Acoustic re£ective data, which are simultaneously obtained with bathymetrical data, are a most powerful tool to distinguish the petit-spots from the Cretaceous edi¢ces in the WPSP and JJST. In this paper, we present the results of an exploratory search for these new kind of petit-spot volcanoes along the trenches in the Paci¢c Ocean, with an emphasis on the Japan and Tonga trenches.The sizes of these irregularly shaped petit-spot volcanoes are several orders of magnitude less than the Cretaceous seamounts and circular knolls, yet they appear to be ubiquitous on the ocean £oor, in particular, where incipient melts in the asthenosphere can be squeezed out by tectonic forces.

Since the initial discovery of hydrothermal vents in 1977, these ‘extreme’ chemosynthetic systems have been a focus of interdisciplinary research. The Okinawa Trough (OT), located in the semi-enclosed East China Sea between the Eurasian continent and the Ryukyu arc, hosts more than 20 known vent sites but all within a relatively narrow depth range (600–1880 m). Depth is a significant factor in determining fluid temperature and chemistry, as well as biological composition. However, due to the narrow depth range of known sites, the actual influence of depth here has been poorly resolved. Here, the Yokosuka site (2190 m), the first OT vent exceeding 2000 m depth is reported. A highly active hydrothermal vent site centred around four active vent chimneys reaching 364°C in temperature, it is the hottest in the OT. Notable Cl depletion (130 mM) and both high H2 and CH4 concentrations (approx. 10 mM) probably result from subcritical phase separation and thermal decomposition of sedimentary organic matter. Microbiota and fauna were generally similar to other sites in the OT, although with some different characteristics. In terms of microbiota, the H2-rich vent fluids in Neuschwanstein chimney resulted in the dominance of hydrogenotrophic chemolithoautotrophs such as Thioreductor and Desulfobacterium. For fauna, the dominance of the deep-sea mussel Bathymodiolus aduloides is surprising given other nearby vent sites are usually dominated by B. platifrons and/or B. japonicus, and a sponge field in the periphery dominated by Poecilosclerida is unusual for OT vents. Our insights from the Yokosuka site implies that although the distribution of animal species may be linked to depth, the constraint is perhaps not water pressure and resulting chemical properties of the vent fluid but instead physical properties of the surrounding seawater. The potential significance of these preliminary results and prospect for future research on this unique site are discussed.