A complex in which this element binds to both phosphorus atoms of bis·di·phenyl·phosphino·ferrocene is used to synthesize pinacol-based boronate esters. After this element coordinates to a double bond, a leaving group is expelled to make a tri·haptic pi-allyl complex in a popular method for asymmetric alkylation. Chlorides of copper and this element are used in the industrial oxidation of ethylene to acet·aldehyde. A reaction that uses this element to synthesize substituted (*) trans-alkenes from a halide and an alkene uses a migratory insertion and a beta-hydride elimination rather than the usual cycle of oxidative addition, transmetallation, and reductive elimination. For 10 points, name this element used in cross-couplings developed (10[1])by Negishi, (10[1]-5[1])Heck, and Suzuki, a white metal used with platinum in catalytic converters. ■END■