Kristall‐zu‐Kristall‐Umwandlung von einem Kettenpolymer zu einem zweidimensionalen Netz bei tiefen Temperaturen

Abstract

Der Umbau von eindimensionalen Ketten (links) zu einem zweidimensionalen Netz (rechts) im Feststoff vollzieht sich in dem Koordinationspolymer [ZnCl2(μ‐bipy)]∞ bei überraschend tiefen Temperaturen von 130 K; oberhalb 360 K erfolgt die Rückreaktion. Die Umwandlung findet sowohl in Einkristallen als auch im Pulver statt. bipy=4,4′‐Bipyridin.

Reversible Breaking and Forming of Metal–Ligand Coordination Bonds: Temperature‐Triggered Single‐Crystal to Single‐Crystal Transformation in a Metal–Organic Framework

“…[18b, 23] The single-crystal to single-crystal transformation described in this report is unusual since it differs from the systems mentioned above in two important aspects: that it consists of a reversibly orchestrated rearrangement of the atoms generated by the breaking/formation of coordination bonds, this case being one of the few in which the stoichiometry of the compound is preserved; and that the single-crystal to singlecrystal phase transition occurs when the crystal is heated at % 130 8C, whereas the only reversible process yet reported in MOFs takes place on cooling. [22] Here, we present the synthesis and a complete single-crystal structural study of the thermal hysteresis cycle at 23, 100, 135, 156, and 20 8C of a novel ytterbium succinate. The study includes variable-temperature IR spectroscopy, and variable-temperature powder XRD of the ytterbium succinate in its two polymorphic forms: the a polymorph, at room temperature; and the b polymorph, at high temperature.…”

“…Keywords: heterogeneous catalysis · metal-organic frameworks · polymorphism · structure elucidation · ytterbium for example: a) sorption/desorption of guest molecules induced by vacuum or temperature changes; [18] b) light; [19] c) rearrangement of solvent molecules; [20] d) a decrease in temperature; [21,22] e) an increase in temperature. [18b, 23] The single-crystal to single-crystal transformation described in this report is unusual since it differs from the systems mentioned above in two important aspects: that it consists of a reversibly orchestrated rearrangement of the atoms generated by the breaking/formation of coordination bonds, this case being one of the few in which the stoichiometry of the compound is preserved; and that the single-crystal to singlecrystal phase transition occurs when the crystal is heated at % 130 8C, whereas the only reversible process yet reported in MOFs takes place on cooling.…”

Crystal‐to‐Crystal Transformation of Magnets Based on Heptacyanomolybdate(III) Involving Dramatic Changes in Coordination Mode and Ordering Temperature

“…[1] It is challenging, however, to obtain high-quality crystals after solid-state transformations, especially those involving the breaking and formation of chemical bonds. [2][3][4][5] Some rare examples are single-crystal transformations of coordination polymers that change their dimensionality, such as 1D to 2D, 1D to 3D, and 2D to 3D. [3] as well as 0D compounds to 1D and 2D coordination polymers.…”

“…[2][3][4][5] Some rare examples are single-crystal transformations of coordination polymers that change their dimensionality, such as 1D to 2D, 1D to 3D, and 2D to 3D. [3] as well as 0D compounds to 1D and 2D coordination polymers. [4] Although various crystal-to-crystal transformations have been reported in recent years, very few examples involve drastic changes in the magnetic properties.…”

Guest‐Induced Instant and Reversible Crystal‐to‐Crystal Transformation of 1,4‐Bis(ferrocenylethynyl)anthraquinone

“…In view of the conformational change required, the fast transformation is particularly remarkable. [14] These features are derived from the flexibility of the crystal structure as a result of the D-A interaction, which is weaker than other chemical bonds, and from the higher stability of 1·THF compared with solvent-free 1 (DG = À32 kJ mol À1 [17] ). Diffuse reflectance UV/Vis spectra of 1·THF and solvent-free 1 indicated appearance of a CT band that is not present in the spectrum of 1 in solution and a red shift of the CT band for 1·THF (l max = 619 nm) from that of solvent-free 1 (l max = 601 nm; see the Supporting Information).…”