Synthese und Kristallstruktur von [KNPPh3]6 · 4 C7H8

Synthesis and Crystal Structure of [KNPPh₃]₆ · 4 C₇H₈ [KNPPh₃]₆ · 4 C₇H₈ ( 1 ) has been prepared from HNPPh₃ and potassium hydride in boiling toluene forming pale yellow moisture sensitive crystals, which were characterized by a crystal structure determination. Space group P1, Z = 2, lattice dimensions at –83 °C: a = 1517.9(2), b = 1894.0(2), c = 2150,4(2) pm, α = 84.39(1)°, b = 89.31(1)°, c = 89.97(1)°, R₁ = 0.0684. 1 forms a K₆N₆ skeleton of a double cube with a common face of two K and two N atoms, the latter being fivefold coordinated by four K atoms and the P atom of the PPh₃ groups.     

Water de/adsorption associated with single‐crystal‐to‐single‐crystal structural transformation of a series of two‐dimensional metal–organic frameworks, [M(bipy)(C4O4)(H2O)2]·3H2O (M = Mn (1), Fe (2), and Zn (3), and bipy=4,4′‐bipyridine)

An assembly of three metal coordination polymers (CPs), [M(bipy)(C₄O₄)(H₂O)₂]·3H₂O (M = Mn ( 1 ), Fe ( 2 ), Zn ( 3 ), and bipy = 4,4′‐bipyridine, C₄O₄^2? (squarate) = dianion of H₂C₄O₄ (squaric acid)), was synthesized and structurally characterized. Single‐crystal X‐ray structural determination reveals that compounds 1 – 3 are iso‐structural, in which the M(II) ions are six‐coordinate in a distorted octahedral geometry. C₄O₄^2? and bipy both act as bridging ligands with bis‐monodentate coordination mode connecting the M(II) ions to form a two‐dimensional (2D) layered metal–organic framework (MOF). Adjacent 2D layers are then arranged in parallel and interpenetrated manners to construct their three‐dimensional (3D) supramolecular architecture. Compounds 1 , 2 , and 3 undergo two‐step dehydration processes with the first and second weight losses of 14.1 and 8.6% for 1 , of 12.1 and 7.5% for 2, and of 11.2 and 8.1% for 3 , respectively, corresponding to the weight losses of the three guest water molecules and the two coordinated water molecules, and all exhibit reversible sponge‐like water de/adsorption properties during de/rehydration processes for guest water molecules as per cyclic thermogravimetric analysis (TGA). The single‐crystal‐to‐single‐crystal (SCSC) structural transformation during the reversible de/rehydration processes of three guest water molecules was identified and monitored using exhaustive single‐crystal and powder X‐ray diffraction measurements.