Correlation between Chemical and Physical Pressures on Charge Bistability in [Pd(en)₂Br](Suc‑C_<i>n</i>)₂·H₂O

Hydrostatic (physical) pressure effects on the electrical resistivity of a bromido-bridged palladium compound, [Pd­(en)₂Br]­(Suc-C₅)₂·H₂O, were studied. The charge-density-wave to Mott–Hubbard phase transition temperature (<i>T</i>_PT) steadily increased with pressure. By a comparison of the effects of the chemical and physical pressures on <i>T</i>_PT, it was estimated that the chemical pressure by unit alkyl chain length, i.e., the number of carbon atoms in the alkyl chains within the counterion, corresponded to ca. 1.3 kbar of the physical pressure

New BDH-TTP/[M^III(C₅O₅)₃]^3– (M = Fe, Ga) Isostructural Molecular Metals

Two new isostructural molecular metals(BDH-TTP)₆[M^III(C₅O₅)₃]·CH₂Cl₂ (BDH-TTP = 2,5-bis­(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, where M = Fe (<b>1</b>) and Ga (<b>2</b>))have been prepared and fully characterized. Compound <b>1</b> is a molecular conductor showing paramagnetic behavior, which is due to the presence of isolated [Fe­(C₅O₅)₃]^3– complexes with high-spin <i>S</i> = ⁵/₂ Fe­(III) metal ions. The conductivity originates from the BDH-TTP organic donors arranged in a κ-type molecular packing. At 4 kbar, compound <b>1</b> behaves as a metal down to ∼100 K, showing high conductivity (∼10 S cm^–1) at room temperature. When applying a pressure higher than 7 kbar, the metal–insulator (M-I) transition is suppressed and the compound retains the metallic state down to low temperatures (2 K). For <b>1</b>, ESR signals have been interpreted as being caused by the fine structure splitting of the high-spin (<i>S</i> = ⁵/₂) state of Fe­(III) in the distorted octahedral crystal field from the ligands. At 4 kbar, the isostructural compound <b>2</b> behaves as a metal down to ∼100 K, although it is noteworthy that the M-I transition is not suppressed, even at pressures of 15 kbar. For <b>2</b>, only the signal assigned to delocalized π-electrons has been observed in the ESR measurements

New BDH-TTP/[M^III(C₅O₅)₃]^3– (M = Fe, Ga) Isostructural Molecular Metals

Two new isostructural molecular metals(BDH-TTP)₆[M^III(C₅O₅)₃]·CH₂Cl₂ (BDH-TTP = 2,5-bis­(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, where M = Fe (<b>1</b>) and Ga (<b>2</b>))have been prepared and fully characterized. Compound <b>1</b> is a molecular conductor showing paramagnetic behavior, which is due to the presence of isolated [Fe­(C₅O₅)₃]^3– complexes with high-spin <i>S</i> = ⁵/₂ Fe­(III) metal ions. The conductivity originates from the BDH-TTP organic donors arranged in a κ-type molecular packing. At 4 kbar, compound <b>1</b> behaves as a metal down to ∼100 K, showing high conductivity (∼10 S cm^–1) at room temperature. When applying a pressure higher than 7 kbar, the metal–insulator (M-I) transition is suppressed and the compound retains the metallic state down to low temperatures (2 K). For <b>1</b>, ESR signals have been interpreted as being caused by the fine structure splitting of the high-spin (<i>S</i> = ⁵/₂) state of Fe­(III) in the distorted octahedral crystal field from the ligands. At 4 kbar, the isostructural compound <b>2</b> behaves as a metal down to ∼100 K, although it is noteworthy that the M-I transition is not suppressed, even at pressures of 15 kbar. For <b>2</b>, only the signal assigned to delocalized π-electrons has been observed in the ESR measurements