The electrical and mechanical properties of the Tetrakis[4-(carboxy methoxy)phenyl]-porphyrin (TCMOPP) and its derivatives

Porphyrins have been adopted as one of the most prevalent linkers for the Metal-Organic Frameworks (MOFs) due to their coordination capacity. However, most MOFs are prone to structural collapse, so the research on their mechanical properties has become a key demand. Considering the flexible linker, aryloxy is the key to the folding motion and the N, C, S substitutions may affect key mechanical parameters (hardness and stiffness). Take the Tetrakis[4-(carboxy methoxy)phenyl]-porphyrin (TCMOPP) as a typical example, the electrical and mechanical properties of the TCMOPP and derivatives (TCMOPP-N, TCMOPP-C and TCMOPP-S) have been investigated using density functional theory (DFT). The results reveal that the TCMOPP displays the most robust electrical conductivity. The synthesized MOFs were connected at the O2, O3, O5 and O6 sites are explained by electrostatic potential. The flexibility of the TCMOPP-C is relatively uniform, while the hardness maximum (4.68 GPa) of the TCMOPP-C is the smallest. Poisson’s ratio difference of the TCMOPP-N is as high as 70%. The maximum Young modulus of the TCMOPP-N is up to 3.22[Formula: see text]GPa. The maximum bulk modulus of the TCMOPP-N is 0.46[Formula: see text]GPa. The TCMOPP-N exhibits the most muscular stiffness, but the anisotropy of the internal structure is the most obvious.