Palladium Chemistry in Molten Alkali Metal Polychalcophosphate Fluxes. Synthesis and Characterization of K(4)Pd(PS(4))(2), Cs(4)Pd(PSe(4))(2), Cs(10)Pd(PSe(4))(4), KPdPS(4), K(2)PdP(2)S(6), and Cs(2)PdP(2)Se(6).

Abstract

The reaction of Pd with a molten mixture of A(2)Q(x)()/P(2)Q(5)/Q (A = K, Q = S, x = 3; A = Cs, Q = Se, x = 1) produced the molecular compounds K(4)Pd(PS(4))(2) (I), Cs(4)Pd(PSe(4))(2) (II), and Cs(10)Pd(PSe(4))(4) (III) and the solid-state KPdPS(4) (IV), K(2)PdP(2)S(6) (V), and Cs(2)PdP(2)Se(6) (VI). Compounds I-III are air and water sensitive, while IV-VI are air and water stable. All crystals are red or dark red except those of VI, which are black. All of them exhibit a rodlike shape. Compound I crystallizes in the triclinic space group P&onemacr; (No. 2) with a = 6.380(1) Å, b = 6.897(1) Å, c = 8.999(1) Å, alpha = 87.777(8) degrees, beta = 81.581(8) degrees, gamma = 84.429(9) degrees, and Z = 1. Compound II crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 7.491(2) Å, b = 13.340(2) Å, c = 10.030(3) Å, beta = 92.21(2) degrees, and Z = 2. Compound III crystallizes in the tetragonal space group P&fourmacr;2c (No. 112) with a = b = 13.949(2) Å, c = 11.527(2) Å, and Z = 4. Compound IV crystallizes in the tetragonal space group P4(2)/mnm (No. 136) with a = b = 8.5337(2) Å, c = 10.5595(5) Å, and Z = 4. Compound V crystallizes in the orthorombic space group Pnma (No. 62) with a = 15.612(2) Å, b = 7.0724(7) Å, c = 10.080(1) Å, and Z = 4. Compound VI crystallizes in the monoclinic space group C2/c (No. 15) with a = 12.9750(4) Å, b = 8.3282(2) Å, c = 13.0568(1) Å, beta = 102.940(2) degrees, and Z = 4. Compounds I-III contain the discrete complexes [Pd(PQ(4))(2)](4)(-) (Q = S, Se). The mixed salt III contains additional noncoordinating [PSe(4)](3)(-) units. The structure of IV consists of Pd(II) in square planar sulfur coordination linked by edge-sharing [PS(4)](3)(-) tetrahedral groups to produce one-dimensional chains. The structures of V andVI feature the [P(2)Q(6)](4)(-) (Q = S, Se) group coordinated to the square planar Pd(2+) atoms, yielding [PdP(2)Q(6)](n)()(2)(n)()(-) chains. Physical characterization was performed with DTA, far-IR spectroscopy, solid-state UV/vis diffuse reflectance spectroscopy, and single-crystal optical transmission.