2D-Grid Layered Pd-Based Cationic Infinite Coordination Polymer/Polyoxometalate Crystal with Hydrophilic Sorption

The inorganic−organic hybrid compound composed of the novel infinite-chain Pd(II) complex and the polyoxometalate
({[(en)Pd(p-bpy)]2[α-SiW12O40]·8DMSO·4DMF}∞ (1a:1 with 8DMSO·4DMF; monoclinic P21/c (No. 14), a = 15.0188(3)
Å, b = 15.6962(3) Å, c = 26.9793(6) Å, β = 106.3580(10)°, V = 6102.6(2) Å3) has been successfully synthesized
by the reaction of [(en)Pd(OH2)2]2[α-SiW12O40] (2) with 4,4‘-bipyridine (p-bpy). The treatment in dry N2 at 50 °C or
evacuation at room temperature forms {[(en)Pd(p-bpy)]2[α-SiW12O40]·6.0DMSO}∞ (1b:1 with 6DMSO) with a drastic
reduction of the interlayer spacing, which is characterized by the powder diffraction analysis and the single-crystal
analysis of 1c (1 with 4.5DMSO·3.5DMF; monoclinic P21/a (No. 14), a = 14.200(9) Å, b = 22.8865(8) Å, c =
14.8558(5) Å, β = 114.7990(10)°, V = 4383.0(2) Å3). Compound 1b reversibly sorbs the hydrophilic molecules
with the maintenance of the intrinsic structure, which is much different from hydrophobic guest-inclusion properties
reported in the other Pd-based supramolecular systems.