Metal-organic frameworks (MOFs) have emerged as a unique class of solid-state materials, exemplifying the power of combining organic and inorganic chemistries to address the enduring challenge pertaining to designing solid state materials with desired attributes. Notably, a myriad of MOFs were constructed in the last two decades. In particular, the use of well-defined polyatomic clusters as molecular building blocks (MBBs) permitted access to the looked-for geometrical features, incorporated in preselected building units prior to the assembly process, guiding the assembly of a targeted network. Nevertheless, the diverse coordination modes and geometries of rareearth (RE) elements requires the introduction of a sophisticated controlled approach for their use as polynuclear cluster MBBs. Subsequently, our group has introduced the use of 2-fluorobenzoic acid (2-FBA) modulator that consistently allows the in situ control and formation of multi-nuclear RE MBBs. The presented work in this thesis demonstrates the use of elaborate RE MBBs and their successful deployment in reticular chemistry for the construction of particular MOF platforms expressing unique properties in term of gas separations. Accordingly, the RE hexanuclear clusters were used to construct fcu- and fluMOF platforms with controlled pore-aperture sizes. Markedly, the isolated RE-MOFs, REfum-fcu-MOF and RE-bqdc-flu-MOF, showed unprecedented paraffin/isoparaffin molecular sieving. Further tuning of the windows of RE-fcu-MOFs afforded the assembly of a MOF suitable for propylene/propane separation. The exceptional thermal and chemical stability and high adsorption selectivity of some of these MOFs prompted us to explore the fcu-MOF platform for selective removal of H2S/CO2 from CH4 and for sensing of toxic gases, namely H2S and NH3. Additionally, the research presented in this dissertation highlights the topological exploration for the formation of new MOFs: i) highly-connected polyatomic RE-MOFs in combination with tetrahedrally oriented tetracarboxylate ligands afforded the formation MOFs with new underlying topologies, namely kna-, kel- and kem-MOFs; ii) mixed-metal approach (RE plus other elements) was employed to fabricate MOFs containing in situ formed metalo-linker MBBs that are difficult to be pre-assembled by organic synthesis; iii) supermolecular building layer (SBL) approach was extended from the prevalent sql to the less explored double sql layer for the rational design of pillared MOFs.

Abstract: Metal-Organic Frameworks (MOFs) are a class of highly porous, hybrid, functional and crystalline extended coordination compounds. Their exceptional properties renders them ideal for a wide range of applications including gas storage and catalysis. Especially for catalysis, MOFs are receiving attention as well-defined supports for organometallic heterogeneous catalysis with noticeably the post-synthetic grafting of transition metal complexes on secondary building units (SBU) containing hydroxides moieties. The objective of this dissertation is to explore the synthesis, reactivity and functionalization of MOFs with SBU containing hydroxides units by transition metal catalyst using the Surface Organometallic Chemistry (SOMC) approach. Chapter 1, gives an introduction to the field of MOF and their applications to catalysis through the functionalization of hydroxide containing SBUs. This chapter introduces also the SOMC strategy with an overview of its catalytic application for olefin metathesis and CO2 conversion. Chapter 2 and 3 give a detailed application of SOMC to MOFs with the selective grafting of the W(≡CtBu)(CH2tBu)3 complex on the highly crystalline and mesoporous Zr-NU-1000 MOF. The obtained single site material, Zr-Nu-1000-W, is fully characterized using state of the art experimental methods and all the steps leading to the final grafted moieties were identified by DFT. Zr-NU-1000-W is active for olefin metathesis and is further fine-tuned by activation with EtAlCl2 giving a more selective and stable catalyst. Moreover, the nature of the grafted species could be modulated by pre-activation of the initial W(≡CtBu)(CH2tBu)3 complex with dmpe giving W(≡CtBu)(=CHtBu)(CH2tBu)(dmpe) also grafted on Zr-NU-1000. Chapter 4 and 5, describe the deliberate design and bulk synthesis of a new zirconium MOF, Zr-she-MOF-2, and highlight the discovery of a new highly connected MOF, RE-urx-MOF-1, based on a careful combination of rare earth (RE) metals with heterobifunctional triangular tetrazolate-based ligand. Additionally, the replacement of the tetrazolate functionality by carboxylate, leads to the formation of a different MOF structure RE-gea-MOF-4 having the gea topology with the presence of 18-connected nonanuclear RE cluster. Both Zr-she-MOF-2 and RE-gea-MOF-4 are active for the coupling of epoxides with CO2 to form cyclic carbonate in the presence of Bu4NBr. Finally, Chapter 6 will discuss the conclusions and perspectives of this dissertation.

The rational design and construction of Metal-Organic Frameworks (MOFs) with intricate structural complexity are of prime importance in reticular chemistry. However, the design of intricate structures that can practically be synthesized is very difficult, and the suitable targeted intricate nets are still unexplored. Evidently, it is of great value to build the fundamental theory for the design of intricate structures. This dissertation is focused on the exploration of cutting-edge design methodologies in reticular chemistry. This research shows the design and synthesis of several MOF platforms (hex, fcu, gea and the) based on rare earth polynuclear clusters. Furthermore, this research unveils the latest addition, named merged nets approach, to the design toolbox in reticular chemistry for the rational design and construction of intricate mixed-linker MOFs. In essence, a valuable net for design enclosing two edges is rationally generated by merging two edge-transitive nets, spn and hxg. The resultant merged net, named sph net, offers potential for the deliberate design and construction of highly symmetric isoreticular intricate mixed-linker MOFs, sph-MOF-1 to 4, which represent the first examples of MOFs where the underlying net is merged from two 3-periodic edge-transitive nets. Furthermore, the underlying principle of the merged net approach, the fundamental merged net equation, and two key parameters are disclosed. Also, we discovered three analysis methods to check and validate corresponding signature nets in an edge-transitive net. Based on these analysis methods, a signature map of all edge-transitive nets was established. This map showing the systematic relationship among edge-transitive nets will help the material chemist to comprehend more about the underlying nets in reticular chemistry. Based on the revealed map, we systematically described the nine types of merging combination and 140 merged nets based on two edge-transitive nets. Among these enumerated nets, only 18 of them was shown on the RCSR database before. These enumerated merged nets significantly increased the designable targets in reticular chemistry. Using an example of enumerated sub net, we show how this approach can be utilized to design and synthesis mixed-linker porous materials based on the intricate sub-MOF platform, which presents one of the most intricate MOF structures synthesized by design.