Abstract:
A bifunctional, microporous ZnII metal–organic
framework, [Zn2
(NH2BDC)2
(dpNDI)]n
(MOF1) (where,
NH2BDC=2-aminoterephthalic acid, dpNDI=N,N’-di(4-pyridyl)-1,4,5,8-naphthalenediimide) has been synthesized solvothermally. MOF1 shows an interesting two-fold interpenetrated, 3D pillar-layered framework structure composed of
two types of 1D channels with dimensions of approximately
2.99V3.58 a and 4.58V5.38 a decorated with pendent @NH2
groups. Owing to the presence of a basic functionalized
pore surface, MOF1 exhibits selective adsorption of CO2 with
high value of heat of adsorption (Qst=46.5 kJmol@1
) which is
further supported by theoretically calculated binding energy
of 48.4 kJmol@1
. Interestingly, the value of Qst observed for
MOF1 is about 10 kJmol@1 higher than that of analogues
MOF with the benzene-1,4-dicarboxylic acid (BDC) ligand,
which establishes the critical role of the @NH2 group for CO2
capture. Moreover, MOF1 exhibits highly selective and sensitive sensing of the nitroaromatic compound (NAC), 2,4,6-trinitrophenol (TNP) over other competing NACs through a luminescence quenching mechanism. The observed selectivity
for TNP over other nitrophenols has been correlated to
stronger hydrogen bonding interaction of TNP with the
basic @NH2 group of MOF1, which is revealed from DFT calculations. To the best of our knowledge, MOF1 is the first example of an interpenetrated ZnII-MOF exhibiting selective
adsorption of CO2 as well as efficient aqueous-phase sensing
of TNP; investigated through combined experimental and
theoretical studies.
