A Porous Coordination Polymer Exhibiting Reversible Single-Crystal to Single-Crystal Substitution Reactions at Mn(II) Centers by Nitrile Guest Molecules

Abstract

The porous coordination polymer {[Mn(L)(H(2)O)](H(2)O)(1.5)(DMF)}(n) (1) containing a water molecule coordinated at the apical position of each distorted octahedral Mn(II) center has been synthesized using the solvothermal technique by reacting Mn(NO(3))(2) x 4 H(2)O with a new flexible ligand (LH(2)) having isophthalic fragment and pyridine donors at the two ends. The coordinated water molecule could be substituted by nitrile guest molecules such as acetonitrile, acrylonitrile, allylnitrile, and crotononitrile (affording compounds 2-5, respectively) without loss of crystallinity. Interestingly, compound 1 selectively captures cis-crotononitrile into its cavity from a mixture of cis and trans isomers. Hence, the cis isomer can be separated from the trans isomer. In each case, 1.5 lattice water molecules and a dimethylformamide (DMF) molecule are also simultaneously replaced by certain numbers of these guest molecules. When these first-generation compounds 2-5 are dipped in DMF at room temperature with the lid of the vial open to the atmosphere, the mother crystal 1 is regenerated in each case. Thus, all of these substitution reactions are completely reversible. Also, the first-generation compounds 2-5 can be interconverted among one another by dipping them in appropriate nitrile guests. All of these phenomena could be observed in single-crystal to single-crystal fashion.

Dynamic Calcium Metal–Organic Framework Acts as a Selective Organic Solvent Sponge

“…On the other hand, the original structure can often be restored by exposing the dry material to the guest again. These structural transformations can take place as 1) single-crystal to single-crystal transformations [14,15] or 2) crystal to crystal (CC) (losing the single crystal integrity) transformations. To appreciate the structural features of these guest-induced transformations, X-ray powder diffraction (XRPD) methods and computational methods need to be applied.…”

Crystal structure of 2-(1-oxoisoindolin-2-yl)acetic acid, C10H9NO3

“…Thetitle compound was synthesized according to the procedures previously described [1,2].Amixture of KOH (25 mmol, 1.39g) and glycine (25 mmol, 1.88g) in 20 mL CH 3 OH wasstirred for30 minutes at room temperature. Amixture of KOH (25 mmol, 1.40 g) and 2-carboxybenzaldehyde (25 mmol, 3.75 g) in 40 mL CH 3 OH was stirred for 30 minutes at room temperature, too.…”

catena-Poly[[diaquabis{μ2-3,5-bis[(pyridin-4-yl)methylamino]benzoato}nickel] monohydrate]

“…For background to metal-organic hybrid materials, see: Bradshaw et al (2005); Das & Bharadwaj (2009) ;Hua et al (2010). For the use of N-, or O-multidentate donor ligands as building blocks in the construction of infinite frameworks, see: Peng et al (2010).…”

“…During the past few decades, growing interests have been focused on the rapidly expanding field of crystal engineering of metal-organic frameworks (MOFs) due to their intriguing architectures as well as their tremendous potential applications in heterogeneous catalysis, ion-recognition, nonlinear optics and molecular adsorption (Bradshaw et al, 2005;Das & Bharadwaj, 2009;Hua et al, 2010). One of the effective strategies for construction of such polymers is to select suitable multidentate organic ligands as building blocks to link metal centers into infinite framework.…”