Halide-Coordinated Products

Incorporation of CO into an organic substrate usually occurs by insertion of CO into a C-metal bond. The requisite Cl-metal bond is formed by oxidative addition of a Pd(0) species into the Cl-Br bond, the normal first step upon combining a Pd(0) compound and an aryl halide. Coordination and insertion of CO follows. Addition of N to the carbonyl and loss of Pd(0) gives an iminium ion, which is trapped by EtOH to give the product. 

An unusual 1,3-coupling is the reaction of nonenolizable /J-oxothioketones with alkylmag-nesium halides, giving products 10 with the hydroxy and alkylthio group cis. The reaction proceeds via an initial thiophilic attack, whereby the Grignard reagent is coordinated to the carbonyl oxygen. 

With metal halides the products isolated commonly contain coordinated halide. In the salt [Ni(pyNO)6]l2 the iodide is not coordinated but pyNO is lost at 100 °C to give [Nil2(pyNO)4], The halide is not necessarily coordinated to the same metal centre as the O-donor CoCl2 3pyNO is almost certainly [Co(pyNO)f ][CoCl4]. The iron complexes FeClj 2L, where L is pyNO, 2-picNO, 4-picNO and 2,4-lutNO, are all of the form [FeCl2L4][FeCl4]. 

The next major commodity plastic worth discussing is polypropylene. Polypropylene is a thermoplastic, crystalline resin. Its production technology is based on Ziegler s discovery in 1953 of metal alkyl-transition metal halide olefin polymerization catalysts. These are heterogeneous coordination systems that produce resin by stereo specific polymerization of propylene. Stereoregular polymers characteristically have monomeric units arranged in orderly periodic steric configuration. 

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