Polymorph of Dibenzo‐24‐Crown‐8 and its Mercury Complex

Abstract

Abstract. Dibenzo-24-crown-8 is studied herein as a flexible ligand able to adopt different conformations, as well as for the complexation of mercury. The recrystallization of dibenzo-24-crown-8 (DB24C8) from dry THF gives a new polymorphic structure of this ligand. This

Dual-stimuli pseudorotaxane switches under kinetic control

“…29 This macrocycle and the commercially available and widely used dibenzo [24]crown-8 ether (DB24C8) have the same number of 24 atoms along their circumference. Nevertheless, the substitution of two catechol oxygen by sulfur atoms affects both the structure and the conformational properties of the ring, 31 as becomes clear, when comparing the new solid state structure of TTFC8 (Fig. 2, also see ESI section 8) with the known structure of DB24C8.…”

“…2, also see ESI section 8) with the known structure of DB24C8. 31 Figure 1 (a) Range of macrocycle exchange rates from a quickly reversible pseudorotaxanesformation (light blue, small 'speed bump') to a fully interlocked rotaxane (red stopper). (b) Stimuli-induced shuttling or unthreading and (c) the corresponding changes of the energy landscapes of a pseudorotaxane as well as (d,e) of a rotaxane (stoppers: green/red, steric 'speed bump' in the axle: blue, TTF oxidation states in yellow (reduced) / orange (oxidized to TTF 2+ ).…”

Mixed metal multinuclear Cr(III) cage compounds and coordination polymers based on unsubstituted phenolate: design, synthesis, mechanism, and properties

“…25 Our single crystal analysis at 150 K gives a = 12.410(2) Å, b = 12.994(2) Å, c = 15.053(2) Å, α = 98.43(1)°, β = 106.211(9)°, γ = 116.731(8)°, P1̅ . 26 [CrCl 2 (THF) 2 ] 1: CrCl 2 (0.10 g, 0.8 mmol) was dried for 1 h under a vacuum at 350°C and then dissolved in 30 mL of dried THF, heating to reflux under magnetic stirring during 1 h. Afterward the solution was filtered under argon, and the solution was concentrated and kept at room temperature. Green single crystals of 1 suitable for X-ray analysis grew in 2 weeks with a yield of 10%.…”

Crystallography for University Research: Some Basic Case Studies

“…[27] A recent example of polymorphism at the University of Fribourg is that of dibenzo-24-crown-8, for which two polymorphs have been crystallized. [28] They are Single Crystal Structure Resolution "The great advantage of X-ray analysis as a method of chemical structure analysis is its power to show totally unexpected and surprising structures with, at the same time, complete certainty. "…”