Industrial & Engineering Chemistry Research, Vol.56, No.11, 2917-2924, 2017
Synthesis, Structure, and Properties of New Mg(II)-Metal-Organic Framework and Its Prowess as Catalyst in the Production of 4H-Pyrans
A new alkaline metal-organic framework, [Mg-3(NDC)(3)(DMF)(4)]center dot H2O (1) is synthesized solvothermally by using 2,6-naphthalenedicarboxylic acid (NDC) as ligand and dimethylformamide (DMF) and water as mixed solvent. Single crystal X-ray studies show that 1 crystallizes in the space group C2/c with parameters a = 13.4191(2), b = 18.0669(2), c = 20.9746(3) angstrom, and ss = 99.66(0)degrees. The central metal atom Mg(II) adopts a six coordinated octahedral geometry with carboxylate oxygen atoms and DMF molecules. Due to the involvement of oxygen atoms in bridging and chelation binding, a trinuclear secondary building unit is built up, which further connects to other six NDC ligands and finally leading to a three-dimensional network. The thermal and luminescent analysis revealed that the compound is thermally stable with violet emission. The creation of coordinatively unsaturated Mg(11) centers, acting as Lewis-acidic sites upon activation, are explored to use 1 as heterogeneous catalyst in-value-added organic conversions. MOP showed a superb catalytic performance in the synthesis of eight 4H-pyran derivatives via one-pot three,component:reaction between aromatic aldehydes, malononitrile, and cyanoacetamide at tooth temperature. All the reactions worked exceptionally well with excellent yields (91-96%), in short reaction times (<40 min). Green solvent (ethanol) and easy separation, reusability and robust structure of catalyst are the attractions of the protocol and make [Mg-3(NDC)(3)(DMF)(4)]center dot H2O an ideal catalyst for wide-ranging organic transformations.