Ferrocenyl phosphine mobility, positional isomerism and NMR fluxionality in triangular palladium sulfide aggregates. Crystal and molecular structuresof [Pd3Cl2(eta(2)-dppf)(mu-dppf)(mu(3)-S)(2)] and [Pd3Cl(eta(2)-dppf)(2)(PPh3)(mu(3)-S)(2)]X [X = Cl or NO3, dppf = Fe(eta(5)-C5H4PPh2)(2)]

Three {Pd3S2} aggregates, [Pd3Cl2(eta(2)-dppf)(mu-dppf)(mu(3)-S)(2)] and [P d3Cl(eta(2)-dppf)(2)(PPh3)(mu(3)-S)(2)]X [X = Cl or NO3, dppf = 1,1'-bis(di phenylphosphino)ferrocene] have been synthesized from metal addition to a { Pd2S2} molecular core in [Pd-2(dppf)(2)(mu-S)(2)]. X-Ray single-crystal cry stallographic analysis revealed a common sulfide-bicapped triangle with ins ignificant Pd Pd interactions. The former is neutral with a bridging and a chelating dppf ligand as well as two terminal chlorides. The dynamic behavi our has been studied by variable temperature P-31 and 2-D COSY NMR. A phosp hine-chloride interchange and phosphine-phosphine exchanges enable the two dppf ligands to migrate around the Pd, plane. The solid-state structure cor responds to the static structure in solution at 198 K. The mixed phosphine complex 5a (X = Cl) is ionic with two Pd-dppf chelating rings and a {Pd(PPh 3)Cl} moiety. With a PPh3 group taking up one site, it is stereochemically rigid. The other two complexes were studied by electrospray mass spectromet ry (ESMS) in solution. The {Pd3S2} core in the mixed phosphine (X = NO3) is relatively stable to fragmentation under ESMS conditions.