Materials used for innovative storage and separation technologies must exhibit long-term stability, possess specific targeting and/or recognition ability and not pose environmental hazards or health effects. From these points of view, metal-organic framework (MOF) materials can be considered as prospective functional adsorbents with regular nano-sized spaces and unique recognition ability [1,2]. The fist-principles calculations have become an indispensable research tool since the computing power has grown rapidly in the last decade and often experiments require theoretical interpretation. Due to the regularity of MOFs, in a computer simulation their structural models can easily be constructed that are very helpful to estimate their physical-chemical properties. Recently, a conceptual design for functional 3D porphyrin-based nanostructures have been presented. Three major motifs for functional nanostructures which vary by three- or four-fold topology, porosity, degree of conjugation, and electronic structures have been explored [3]. Here, the proposed building blocks were used to construct MOF structures. The electronic structure, thermodynamic stability and the possibility the encapsulation CdSe quantum dots (QDs) with 1.5 nm have been studied. The interpenetration effect on thermodynamic stability of MOF structures with high pore size has been also studied. The well-known binuclear carboxylate complexes having an octahedral geometry (Zn2(R)4L2) have been selected. The biphenyl connected to the Zn metals through pyridine molecules and terphenyldicarboxylate (TPDC) are selected as L and R ligands, respectively. The calculated interaction energies between two frameworks have shown that the interpenetrating structure is energetically more favorable due to attractive interaction between the MOF ligands. The close distances between TPDC of different frameworks can leads to interweaving between two frameworks. The substitution of biphenyl by porphyrin moieties can prevent such adhesion due to the increasing distance between TPDC and results in weaker interaction between two interpenetrating frameworks. It has been shown that introduction of porphyrin can improve the H2 and CH4 adsorption of interpenetrating structure.

Theoretical study of porphyrin-based MOF structure for storage, separation, and drug delivery applications

2019 Fall National Meeting

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