title: Self-alignment of low-valent octanuclear palladium atoms.
abstract: A linear tetraphosphine, meso-bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm) was used to synthesize linear octapalladium-extended metal atom chains as discrete molecules of [Pd8(μ-dpmppm)4](BF4)4 (1) and [Pd8(μ-dpmppm)4L2](BF4)4 (L=2,6-xylyl isocyanide (XylNC; 2), acetonitrile (3), and N,N-dimethylformamide (dmf; 4)), which are stable in the solution states and show interesting temperature-dependent photochemical properties in the near IR region. Variable temperature NMR studies demonstrated that at higher temperature T≈140 °C the Pd8 chains were dissociated into Pd4 fragments, which were thermodynamically self-aligned to restore the Pd8 chains at lower temperature T<60 °C. The coldspray ionization mass spectra suggested a possibility for further aggregation of the linear tetrapalladium units.
authors.affiliation: Department of Chemistry, Faculty of Science, Nara Women's University, Kitauoya-nishi-machi, Nara, 630-8506 (Japan).
authors.forename: Kanako
authors.initials: K
authors.lastname: Nakamae
authors.forename: Yukie
authors.initials: Y
authors.lastname: Takemura
authors.forename: Bunsho
authors.initials: B
authors.lastname: Kure
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakajima
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kitagawa
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tanase
keywords: metal atom chains; octanuclear complexes; palladium; self-assembly; tetraphosphines