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Direct Crystallographic Observation of Catalytic Reactions inside the Pores of a Flexible Coordination Polymer
Author(s) -
Das Raj Kumar,
Aijaz Arshad,
Sharma Manish K.,
Lama Prem,
Bharadwaj Parimal K.
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201200046
Subject(s) - catalysis , polymer , coordination polymer , materials science , crystallography , chemistry , composite material , organic chemistry
A new flexible porous coordination polymer (PCP), {[Gd 2 (L) 3 (dmf) 4 ] ⋅ 4 DMF ⋅ 3 H 2 O} n ( 1 ), was synthesized under solvothermal condition by reacting [Gd(NO 3 ) 3 ] ⋅ 6 H 2 O with the ligand 2,6,2′,6′‐tetranitro‐biphenyl‐4,4′‐dicarboxylic acid (H 2 L). Compound 1 had a 3D coordination polymeric structure with two types of 1D channels (A and B) that were occupied by DMF and water molecules. When crystals of 1 were separately exposed to vapors of various aromatic aldehydes, either the lattice or both the lattice and metal‐bound solvent molecules were replaced by aldehyde molecules. The aldehyde molecules inside the pores spontaneously underwent cyanosilylation and Knoevenagel condensation reactions upon exposure to vapors of trimethylsilyl cyanide and malononitrile, respectively. These reactions took place at ambient temperature and pressure. Moreover, both the reactants and the products translocated from one cavity to another. The products that occupied the cavity were expunged upon exposure to the vapors of an aldehyde. Because crystallinity was maintained during these chemical transformations, direct crystallographic observation was possible. Herein, we showed that confinement of the reactants inside the void spaces of the PCP led to the products; we also assessed catalytic activities of this PCP in bulk quantities.