Dielectric Properties of Selected Metal–Organic Frameworks

The electronic structure of a class
of [Zn4O­(CO2)6] based metal–organic
frameworks (MOFs)
is theoretically analyzed by means of density functional perturbation
theory. The calculated static dielectric constants vary in a range
between 1.33 and 1.54, characterizing the structures as ultralow-k dielectric materials and confirming earlier estimates
qualitatively. We also present the results of first-principle calculations
of the real and imaginary parts of the dielectric function and give
the frequency-dependent dielectric constant up to the near-ultraviolet,
which is important for high frequency semiconductor and optical applications
of MOFs. The dielectric and electronic properties are governed by
the linker molecules, so that the band gap and the dielectric constant
can be engineered.