Cooperative Guest Inclusion by a Zeolite Analogue Coordination Polymer. Sorption Behavior with Gases and Amine and Group 1 Metal Salts

Abstract

Reaction of CuX 2 (X ) NO 3 , Cl, (SO 4 ) 1/2 ) salts and Hpymo‚HX (Hpymo ) 2-hydroxypyrimidine; X ) Cl, NO 3 ) in aqueous amine solutions (amine ) NH 3 , CH 3 NH 2 ) leads to formation of the poorly crystalline three-dimensional open-framework coordination polymer [Cu(pymo-N1,N3) 2 ] ∞ (1). Under the same reaction conditions, but in the presence of amine and group 1 metal salts of single charged voluminous anions, highly crystalline clathrates of the type) are obtained. The X-ray crystal structure of 1‚NH 4 ClO 4 reveals that the combination of square-planar Cu 2+ ion with 120°bond angles provided by Hpymo generates a three-dimensional porous [Cu-(pymo-N1,N3) 2 ] ∞ framework with ammonium and perchlorate ions and water molecules included in the pores. 1 possesses a rich host-guest chemistry. Indeed, N 2 sorption at 77 K by empty host 1 reveals its microporous nature with a BET surface area of ca. 200 m 2 g -1 . Hydrated 1 loses water upon heating and when exposed to moist air regenerates the original hydrated material. Likewise, 1‚NH 4 ClO 4 loses ammonia upon heating, giving the corresponding activated acidic material 1‚HClO 4 which upon exposure to gaseous ammonia regenerates 1‚NH 4 ClO 4 . In addition, 1 reversibly and selectively sorbs AClO 4 salts (A ) NH 4 , Li, Na, K, Rb) when exposed to AClO 4 aqueous solutions giving highly crystalline 1‚AClO 4 clathrates. Cl -, NO 3 -, SiF 6 2-, and SO 4 2salts are, however, not taken up. Salt sorption curves are of type V and possess hysteresis loops. This behavior agrees with the observed guest-induced structure phase change taking place in the 1 framework after guest inclusion.

Mixed‐Metal (Platinum, Palladium), Mixed‐Pyrimidine (Uracil, Cytosine) Self‐Assembling Metallacalix[n]arenes: Dynamic Combinatorial Chemistry with Nucleobases and Metal Species

“…[8] Also, three-dimensional polymeric materials displaying similar structural motifs, for example, rings with four or six metal ions, have been reported, which show interesting adsorption phenomena. [9] A remarkable feature of the discrete metallacalix [n]arenes derived from the pyrimidine nucleobases uracil or thymine is their propensity to add additional square-planar cis-Ma 2 II (M: Pt, Pd) or cis-octahedral metal entities (Ni II , Cu II ) to yield higher nuclearity species. Octanuclear compounds have been derived from Pt-calix [4]arenes [5a, 10] and pentanuclear species from either Pt-calix [4]arenes [4, 5c] or Pt-calix [3]arenes.…”

“…Similar self-pairing schemes have been observed in other metal complexes containing N1-bonded pyrimidine nucleobases. [22] The cytosine ligands of cation II of 1 a also form centrosymmetric pairs, through the N1 À H and O2 sites, with the hydrogen bonds being 2.813 (9) in length (see the Supporting Information). The water molecules and the anions are involved in numerous hydrogen-bonding interactions as well.…”

Selective aerobic oxidation of activated alkanes with MOFs and their use for epoxidation of olefins with oxygen in a tandem reaction

“…We have recently reported 9 that a copper-containing MOF, [Cu(2-pymo) 2 ] (2-pymo = 2-oxypyrimidinolate, 10 ) could be of interest as heterogeneous catalyst for the liquidphase oxidation of tetralin (T-H) using air as oxidant. Under the reactions conditions studied, a relatively high T-H conversion (ca.…”

Reversible Pore Size Control of Elastic Microporous Material by Mechanical Force

“…Some of MOFs that originally have narrow pores can be expanded by the inclusion of guest molecules. [21][22][23][24] Similar pore expansion can be seen in some nanoporous materials with soft frameworks, such as nanoporous polyA C H T U N G T R E N N U N G (imide), [25] and a specific templated carbon. [26] However, these methods cannot be used to control the size of "empty" nanopores.…”