MONOPALLADATION VERSUS DIPALLADATION OF THE DURENE-BASED TETRATHIOETHER LIGAND 1,2,4,5-(TBUSCH(2))(4)C6H2-CENTER-DOT STRUCTURES OF [PDCL((TBUSCH(2))(4)C6H)] AND [PD-2((TBUSCH(2))(4)C-6)(MECN)(2)][BF4](2)

Treatment of 1,2,4,5-(tBuSCH(2))(4)C6H2 with K2PdCl4/NaOAc in ethanol yielded only the monopalladated complex [PdCl((tBuSCH(2))(4)C6H)] rega rdless of whether 1 or 2 equiv of K2PdCl4 is used. Alternately, the re action of 1,2,4,5-(tBuSCH(2))(4)C6H2 with 1 Or 2 equiv of [Pd(MeCN)(4) ][BF4](2) in MeCN resulted in quantitative production of the dipallada ted species [Pd-2((tBuSCH(2))(4)C-6)(MeCN)(2)][BF4](2) based on pallad ium starting material. The X-ray structures of the two products [PdCl( (tBuSCH(2))(4)C6H)] and [Pd-2((tBuSCH(2))(4)C-6)(MeCN)(2)][BF4](2) are reported. MO calculations were consistent with the idea that the liga nd trans to the first Pd-C bond dictates the electrophilic aromatic su bstitution pattern and determines whether a second palladation will oc cur. Thus, Pd-Cl is deactivating while (Pd-MeCN)(+) is activating, res ulting in the formation of exclusively mono- and dipalladated products , respectively.